Merge pull request #1740 from rickard-green/rickard/signals/OTP-14589

Implementation of true asynchronous signaling between processes

48 files changed, 12795 insertions, 6703 deletions

diff --git a/erts/emulator/beam/atom.names b/erts/emulator/beam/atom.names
index 38b5f0c5e3..7963386e1d 100644
--- a/erts/emulator/beam/atom.names
+++ b/erts/emulator/beam/atom.names
@@ -1,7 +1,7 @@
 #
 # %CopyrightBegin%
 #
-# Copyright Ericsson AB 1996-2017. All Rights Reserved.
+# Copyright Ericsson AB 1996-2018. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -106,6 +106,7 @@ atom atom
 atom atom_used
 atom attributes
 atom auto_connect
+atom await_exit
 atom await_microstate_accounting_modifications
 atom await_port_send_result
 atom await_proc_exit
@@ -214,7 +215,6 @@ atom dist_data
 atom Div='/'
 atom div
 atom dmonitor_node
-atom dmonitor_p
 atom DollarDollar='$$'
 atom DollarUnderscore='$_'
 atom dollar_endonly
diff --git a/erts/emulator/beam/beam_bif_load.c b/erts/emulator/beam/beam_bif_load.c
index 87367b44ab..5c76aafae7 100644
--- a/erts/emulator/beam/beam_bif_load.c
+++ b/erts/emulator/beam/beam_bif_load.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1999-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1999-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -37,6 +37,7 @@
 #include "erl_bits.h"
 #include "erl_thr_progress.h"
 #include "erl_nfunc_sched.h"
+#include "erl_proc_sig_queue.h"
 #ifdef HIPE
 #  include "hipe_bif0.h"
 #  define IF_HIPE(X) (X)
@@ -65,7 +66,6 @@ static struct {
 
 Process *erts_code_purger = NULL;
 
-Process *erts_dirty_process_code_checker;
 erts_atomic_t erts_copy_literal_area__;
 #define ERTS_SET_COPY_LITERAL_AREA(LA)			\
     erts_atomic_set_nob(&erts_copy_literal_area__,	\
@@ -607,7 +607,9 @@ BIF_RETTYPE erts_internal_check_dirty_process_code_2(BIF_ALIST_2)
     int reds = 0;
     Eterm res;
 
-    if (BIF_P != erts_dirty_process_code_checker)
+    if (BIF_P != erts_dirty_process_signal_handler
+        && BIF_P != erts_dirty_process_signal_handler_high
+        && BIF_P != erts_dirty_process_signal_handler_max)
 	BIF_ERROR(BIF_P, EXC_NOTSUP);
 
     if (is_not_internal_pid(BIF_ARG_1))
@@ -901,15 +903,59 @@ static void hfrag_literal_copy(Eterm **hpp, ErlOffHeap *ohp,
                                Eterm *start, Eterm *end,
                                char *lit_start, Uint lit_size);
 
+static ERTS_INLINE void
+msg_copy_literal_area(ErtsMessage *msgp, int *redsp,
+                      char *literals, Uint lit_bsize)
+{
+    ErlHeapFragment *hfrag, *hf;
+    Uint lit_sz = 0;
+
+    *redsp += 1;
+
+    if (!ERTS_SIG_IS_INTERNAL_MSG(msgp) || !msgp->data.attached)
+        return;
+
+    if (msgp->data.attached == ERTS_MSG_COMBINED_HFRAG)
+        hfrag = &msgp->hfrag;
+    else
+        hfrag = msgp->data.heap_frag;
+
+    for (hf = hfrag; hf; hf = hf->next) {
+        lit_sz += hfrag_literal_size(&hf->mem[0],
+                                     &hf->mem[hf->used_size],
+                                     literals, lit_bsize);
+        *redsp += 1;
+    }
+
+    *redsp += lit_sz / 16; /* Better value needed... */
+    if (lit_sz > 0) {
+        ErlHeapFragment *bp = new_message_buffer(lit_sz);
+        Eterm *hp = bp->mem;
+
+        for (hf = hfrag; hf; hf = hf->next) {
+            hfrag_literal_copy(&hp, &bp->off_heap,
+                               &hf->mem[0],
+                               &hf->mem[hf->used_size],
+                               literals, lit_bsize);
+            hfrag = hf;
+        }
+
+        /* link new hfrag last */
+        ASSERT(hfrag->next == NULL);
+        hfrag->next = bp;
+        bp->next = NULL;
+    }
+}
+
 Eterm
 erts_proc_copy_literal_area(Process *c_p, int *redsp, int fcalls, int gc_allowed)
 {
     ErtsLiteralArea *la;
-    ErtsMessage *msgp;
     struct erl_off_heap_header* oh;
     char *literals;
     Uint lit_bsize;
     ErlHeapFragment *hfrag;
+    ErtsMessage *mfp;
 
     la = ERTS_COPY_LITERAL_AREA();
     if (!la)
@@ -927,46 +973,13 @@ erts_proc_copy_literal_area(Process *c_p, int *redsp, int fcalls, int gc_allowed
      */
 
     erts_proc_lock(c_p, ERTS_PROC_LOCK_MSGQ);
-    ERTS_MSGQ_MV_INQ2PRIVQ(c_p);
+    erts_proc_sig_fetch(c_p);
     erts_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ);
 
-    for (msgp = c_p->msg.first; msgp; msgp = msgp->next) {
-	ErlHeapFragment *hf;
-	Uint lit_sz = 0;
-
-	*redsp += 1;
-
-	if (msgp->data.attached == ERTS_MSG_COMBINED_HFRAG)
-	    hfrag = &msgp->hfrag;
-	else if (is_value(ERL_MESSAGE_TERM(msgp)) && msgp->data.heap_frag)
-	    hfrag = msgp->data.heap_frag;
-	else
-	    continue; /* Content on heap or in external term format... */
-
-	for (hf = hfrag; hf; hf = hf->next) {
-	    lit_sz += hfrag_literal_size(&hf->mem[0], &hf->mem[hf->used_size],
-					literals, lit_bsize);
-	    *redsp += 1;
-	}
-
-	*redsp += lit_sz / 16; /* Better value needed... */
-	if (lit_sz > 0) {
-	    ErlHeapFragment *bp = new_message_buffer(lit_sz);
-	    Eterm *hp = bp->mem;
-
-	    for (hf = hfrag; hf; hf = hf->next) {
-		hfrag_literal_copy(&hp, &bp->off_heap,
-				   &hf->mem[0], &hf->mem[hf->used_size],
-				   literals, lit_bsize);
-		hfrag = hf;
-	    }
-
-	    /* link new hfrag last */
-	    ASSERT(hfrag->next == NULL);
-	    hfrag->next = bp;
-	    bp->next = NULL;
-        }
-    }
+    ERTS_FOREACH_SIG_PRIVQS(c_p, msgp, msg_copy_literal_area(msgp,
+                                                             redsp,
+                                                             literals,
+                                                             lit_bsize));
 
     if (gc_allowed) {
 	/*
@@ -1041,8 +1054,8 @@ erts_proc_copy_literal_area(Process *c_p, int *redsp, int fcalls, int gc_allowed
      *    process off heap structure.
      *  - Check for literals
      */
-    for (msgp = c_p->msg_frag; msgp; msgp = msgp->next) {
-	hfrag = erts_message_to_heap_frag(msgp);
+    for (mfp = c_p->msg_frag; mfp; mfp = mfp->next) {
+	hfrag = erts_message_to_heap_frag(mfp);
 	for (; hfrag; hfrag = hfrag->next) {
 	    Eterm *hp, *hp_end;
 
diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index fbd0e38735..fb87be3f17 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1996-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1996-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -44,6 +44,7 @@
 #include "hipe_bif1.h"
 #endif
 #include "dtrace-wrapper.h"
+#include "erl_proc_sig_queue.h"
 
 /* #define HARDDEBUG 1 */
 
@@ -1454,7 +1455,7 @@ handle_error(Process* c_p, BeamInstr* pc, Eterm* reg, ErtsCodeMFA *bif_mfa)
 	reg[3] = c_p->ftrace;
         if ((new_pc = next_catch(c_p, reg))) {
 	    c_p->cp = 0;	/* To avoid keeping stale references. */
-            c_p->msg.saved_last = 0;  /* No longer safe to use this position */
+            ERTS_RECV_MARK_CLEAR(c_p); /* No longer safe to use this position */
 	    return new_pc;
 	}
 	if (c_p->catches > 0) erts_exit(ERTS_ERROR_EXIT, "Catch not found");
@@ -2419,8 +2420,8 @@ erts_hibernate(Process* c_p, Eterm* reg)
      * shrink the heap. 
      */
     erts_proc_lock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS);
-    ERTS_MSGQ_MV_INQ2PRIVQ(c_p);
-    if (!c_p->msg.len) {
+    erts_proc_sig_fetch(c_p);
+    if (!c_p->sig_qs.len) {
 	erts_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS);
 	c_p->fvalue = NIL;
 	PROCESS_MAIN_CHK_LOCKS(c_p);
@@ -2428,8 +2429,8 @@ erts_hibernate(Process* c_p, Eterm* reg)
 	ERTS_VERIFY_UNUSED_TEMP_ALLOC(c_p);
 	PROCESS_MAIN_CHK_LOCKS(c_p);
 	erts_proc_lock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS);
-        ERTS_MSGQ_MV_INQ2PRIVQ(c_p);
-	if (!c_p->msg.len)
+        erts_proc_sig_fetch(c_p);
+	if (!c_p->sig_qs.len)
 	    erts_atomic32_read_band_relb(&c_p->state, ~ERTS_PSFLG_ACTIVE);
 	ASSERT(!ERTS_PROC_IS_EXITING(c_p));
     }
diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index 652b95105f..adea7d007e 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1996-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1996-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -46,8 +46,10 @@
 #include "erl_bif_unique.h"
 #include "erl_map.h"
 #include "erl_msacc.h"
+#include "erl_proc_sig_queue.h"
 
 Export *erts_await_result;
+static Export await_exit_trap;
 static Export* flush_monitor_messages_trap = NULL;
 static Export* set_cpu_topology_trap = NULL;
 static Export* await_proc_exit_trap = NULL;
@@ -92,83 +94,51 @@ BIF_RETTYPE spawn_3(BIF_ALIST_3)
 /* Utility to add a new link between processes p and another internal
  * process (rpid). Process p must be the currently executing process.
  */
-static int insert_internal_link(Process* p, Eterm rpid)
-{
-    Process *rp;
-    ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK;
-
-    ASSERT(is_internal_pid(rpid));
-
-    if (IS_TRACED(p)
-	&& (ERTS_TRACE_FLAGS(p) & (F_TRACE_SOL|F_TRACE_SOL1))) {
-	rp_locks = ERTS_PROC_LOCKS_ALL;
-    }
-
-    erts_proc_lock(p, ERTS_PROC_LOCK_LINK);
-
-    /* get a pointer to the process struct of the linked process */
-    rp = erts_pid2proc_opt(p, ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_LINK,
-			   rpid, rp_locks,
-			   ERTS_P2P_FLG_ALLOW_OTHER_X);
-
-    if (!rp) {
-	erts_proc_unlock(p, ERTS_PROC_LOCK_LINK);
-	return 0;
-    }
-
-    if (p != rp) {
-	erts_add_link(&ERTS_P_LINKS(p), LINK_PID, rp->common.id);
-	erts_add_link(&ERTS_P_LINKS(rp), LINK_PID, p->common.id);
-
-	ASSERT(IS_TRACER_VALID(ERTS_TRACER(p)));
-
-	if (IS_TRACED(p)) {
-	    if (ERTS_TRACE_FLAGS(p) & (F_TRACE_SOL|F_TRACE_SOL1))  {
-		ERTS_TRACE_FLAGS(rp) |= (ERTS_TRACE_FLAGS(p) & TRACEE_FLAGS);
-                erts_tracer_replace(&rp->common, ERTS_TRACER(p));
-		if (ERTS_TRACE_FLAGS(p) & F_TRACE_SOL1) { /* maybe override */
-		    ERTS_TRACE_FLAGS(rp) &= ~(F_TRACE_SOL1 | F_TRACE_SOL);
-		    ERTS_TRACE_FLAGS(p) &= ~(F_TRACE_SOL1 | F_TRACE_SOL);
-		}
-	    }
-	}
-    }
-    if (IS_TRACED_FL(rp, F_TRACE_PROCS))
-	trace_proc(p, p == rp ? rp_locks : ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_LINK,
-                   rp, am_getting_linked, p->common.id);
-
-    if (p == rp)
-	erts_proc_unlock(p, rp_locks & ~ERTS_PROC_LOCK_MAIN);
-    else {
-	erts_proc_unlock(p, ERTS_PROC_LOCK_LINK);
-	erts_proc_unlock(rp, rp_locks);
-    }
-
-    return 1;
-}
-
 
 /* create a link to the process */
 BIF_RETTYPE link_1(BIF_ALIST_1)
 {
-    DistEntry *dep;
-
     if (IS_TRACED_FL(BIF_P, F_TRACE_PROCS)) {
 	trace_proc(BIF_P, ERTS_PROC_LOCK_MAIN, BIF_P, am_link, BIF_ARG_1);
     }
     /* check that the pid or port which is our argument is OK */
 
     if (is_internal_pid(BIF_ARG_1)) {
-	if (insert_internal_link(BIF_P, BIF_ARG_1)) {
-	    BIF_RET(am_true);
-	}
-	else {
-	    goto res_no_proc;
-	}
+        int created;
+        ErtsLinkData *ldp;
+        ErtsLink *lnk;
+
+        if (BIF_P->common.id == BIF_ARG_1)
+            BIF_RET(am_true);
+
+        if (!erts_proc_lookup(BIF_ARG_1))
+            goto res_no_proc;
+
+        lnk = erts_link_tree_lookup_create(&ERTS_P_LINKS(BIF_P),
+                                           &created,
+                                           ERTS_LNK_TYPE_PROC,
+                                           BIF_P->common.id,
+                                           BIF_ARG_1);
+        if (!created)
+            BIF_RET(am_true);
+
+        ldp = erts_link_to_data(lnk);
+        
+
+        if (erts_proc_sig_send_link(BIF_P, BIF_ARG_1, &ldp->b))
+            BIF_RET(am_true);
+
+        erts_link_tree_delete(&ERTS_P_LINKS(BIF_P), lnk);
+        erts_link_release_both(ldp);
+        goto res_no_proc;
     }
 
     if (is_internal_port(BIF_ARG_1)) {
-	int send_link_signal = 0;
+        int created;
+        ErtsLinkData *ldp;
+        ErtsLink *lnk;
+        Eterm ref;
+        Eterm *refp;
 	Port *prt = erts_port_lookup(BIF_ARG_1,
 				     (erts_port_synchronous_ops
 				      ? ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP
@@ -177,31 +147,31 @@ BIF_RETTYPE link_1(BIF_ALIST_1)
 	    goto res_no_proc;
 	}
 
-	erts_proc_lock(BIF_P, ERTS_PROC_LOCK_LINK);
-	
-	if (erts_add_link(&ERTS_P_LINKS(BIF_P), LINK_PID, BIF_ARG_1) >= 0)
-	    send_link_signal = 1;
-	/* else: already linked */
-
-	erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_LINK);
+        lnk = erts_link_tree_lookup_create(&ERTS_P_LINKS(BIF_P),
+                                           &created,
+                                           ERTS_LNK_TYPE_PORT,
+                                           BIF_P->common.id,
+                                           BIF_ARG_1);
+        if (!created)
+            BIF_RET(am_true);
 
-	if (send_link_signal) {
-	    Eterm ref;
-	    Eterm *refp = erts_port_synchronous_ops ? &ref : NULL;
+        ldp = erts_link_to_data(lnk);
+        refp = erts_port_synchronous_ops ? &ref : NULL;
 
-	    switch (erts_port_link(BIF_P, prt, BIF_P->common.id, refp)) {
-	    case ERTS_PORT_OP_DROPPED:
-	    case ERTS_PORT_OP_BADARG:
-		goto res_no_proc;
-	    case ERTS_PORT_OP_SCHEDULED:
-		if (refp) {
-		    ASSERT(is_internal_ordinary_ref(ref));
-		    BIF_TRAP3(await_port_send_result_trap, BIF_P, ref, am_true, am_true);
-		}
-	    default:
-		break;
-	    }
-	}
+        switch (erts_port_link(BIF_P, prt, &ldp->b, refp)) {
+        case ERTS_PORT_OP_DROPPED:
+        case ERTS_PORT_OP_BADARG:
+            erts_link_tree_delete(&ERTS_P_LINKS(BIF_P), lnk);
+            erts_link_release_both(ldp);
+            goto res_no_proc;
+        case ERTS_PORT_OP_SCHEDULED:
+            if (refp) {
+                ASSERT(is_internal_ordinary_ref(ref));
+                BIF_TRAP3(await_port_send_result_trap, BIF_P, ref, am_true, am_true);
+            }
+        default:
+            break;
+        }
 	BIF_RET(am_true);
     }
     else if (is_external_port(BIF_ARG_1)
@@ -210,317 +180,203 @@ BIF_RETTYPE link_1(BIF_ALIST_1)
     }
 
     if (is_external_pid(BIF_ARG_1)) {
+        ErtsLinkData *ldp;
+        int created;
+        DistEntry *dep;
+        ErtsLink *lnk;
+        int code;
+        ErtsDSigData dsd;
+
+        dep = external_pid_dist_entry(BIF_ARG_1);
+        if (dep == erts_this_dist_entry)
+            goto res_no_proc;
 
-	erts_proc_lock(BIF_P, ERTS_PROC_LOCK_LINK);
-
-	/* We may earn time by checking first that we're not linked already */
-	if (erts_lookup_link(ERTS_P_LINKS(BIF_P), BIF_ARG_1) != NULL) {
-	    erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_LINK);
-	    BIF_RET(am_true);
-	}
-	else {
-	    ErtsLink *lnk;
-	    int code;
-	    ErtsDSigData dsd;
-	    dep = external_pid_dist_entry(BIF_ARG_1);
-	    if (dep == erts_this_dist_entry) {
-		erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_LINK);
-		goto res_no_proc;
-	    }
-
-	    code = erts_dsig_prepare(&dsd, dep, BIF_P,
-				     (ERTS_PROC_LOCK_MAIN | ERTS_PROC_LOCK_LINK),
-				     ERTS_DSP_RLOCK, 0, 1);
-	    switch (code) {
-	    case ERTS_DSIG_PREP_NOT_ALIVE:
-	    case ERTS_DSIG_PREP_NOT_CONNECTED: {
-		ErtsProcLocks locks = ERTS_PROC_LOCK_MAIN | ERTS_PROC_LOCK_LINK;
-		erts_aint32_t state;
-		erts_proc_lock(BIF_P, (ERTS_PROC_LOCKS_ALL & ~locks));
-		locks = ERTS_PROC_LOCKS_ALL;
-		erts_send_exit_signal(BIF_P, BIF_ARG_1, BIF_P, &locks,
-				      am_noconnection, NIL, NULL, 0);
-		erts_proc_unlock(BIF_P, locks & ERTS_PROC_LOCKS_ALL_MINOR);
-
-		/*
-		 * Copy-paste from old dist_exit_3, not sure if we really
-		 * need erts_handle_pending_exit when exit_2 does not.
-		 */
-		state = erts_atomic32_read_acqb(&BIF_P->state);
-		if (state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_PENDING_EXIT)) {
-		    if (state & ERTS_PSFLG_PENDING_EXIT)
-			erts_handle_pending_exit(BIF_P, ERTS_PROC_LOCK_MAIN);
-		    ERTS_BIF_EXITED(BIF_P);
-		}
-		BIF_RET(am_true);
-	    }
-            case ERTS_DSIG_PREP_PENDING:
-	    case ERTS_DSIG_PREP_CONNECTED:
-                /*
-                 * We have (pending) connection.
-                 * Setup link and enqueue link signal.
-                 */
-		erts_de_links_lock(dep);
-
-		erts_add_link(&ERTS_P_LINKS(BIF_P), LINK_PID, BIF_ARG_1);
-		lnk = erts_add_or_lookup_link(&(dep->nlinks),
-					      LINK_PID,
-					      BIF_P->common.id);
-		ASSERT(lnk != NULL);
-		erts_add_link(&ERTS_LINK_ROOT(lnk), LINK_PID, BIF_ARG_1);
-
-		erts_de_links_unlock(dep);
-		erts_de_runlock(dep);
-		erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_LINK);
-
-		code = erts_dsig_send_link(&dsd, BIF_P->common.id, BIF_ARG_1);
-		if (code == ERTS_DSIG_SEND_YIELD)
-		    ERTS_BIF_YIELD_RETURN(BIF_P, am_true);
-		BIF_RET(am_true);
-	    default:
-		ERTS_ASSERT(! "Invalid dsig prepare result");
-	    }
-	}
+        lnk = erts_link_tree_lookup_create(&ERTS_P_LINKS(BIF_P),
+                                           &created,
+                                           ERTS_LNK_TYPE_DIST_PROC,
+                                           BIF_P->common.id,
+                                           BIF_ARG_1);
+
+        if (!created)
+            BIF_RET(am_true); /* Already present... */
+
+        ldp = erts_link_to_data(lnk);
+
+        code = erts_dsig_prepare(&dsd, dep, BIF_P,
+                                 ERTS_PROC_LOCK_MAIN,
+                                 ERTS_DSP_RLOCK, 0, 1);
+        switch (code) {
+        case ERTS_DSIG_PREP_NOT_ALIVE:
+        case ERTS_DSIG_PREP_NOT_CONNECTED:
+            erts_link_set_dead_dist(&ldp->b, dep->sysname);
+            erts_proc_sig_send_link_exit(NULL, BIF_ARG_1, &ldp->b,
+                                         am_noconnection, NIL);
+            BIF_RET(am_true);
+
+        case ERTS_DSIG_PREP_PENDING:
+        case ERTS_DSIG_PREP_CONNECTED: {
+            /*
+             * We have (pending) connection.
+             * Setup link and enqueue link signal.
+             */
+#ifdef DEBUG
+            int inserted =
+#endif
+                erts_link_dist_insert(&ldp->b, dep->mld);
+            ASSERT(inserted);
+            erts_de_runlock(dep);
+
+            code = erts_dsig_send_link(&dsd, BIF_P->common.id, BIF_ARG_1);
+            if (code == ERTS_DSIG_SEND_YIELD)
+                ERTS_BIF_YIELD_RETURN(BIF_P, am_true);
+            BIF_RET(am_true);
+            break;
+        }
+        default:
+            ERTS_ASSERT(! "Invalid dsig prepare result");
+        }
     }
 
     BIF_ERROR(BIF_P, BADARG);
 
-res_no_proc: {
-	erts_aint32_t state = erts_atomic32_read_nob(&BIF_P->state);
-	if (state & ERTS_PSFLG_TRAP_EXIT) {
-	    ErtsProcLocks locks = ERTS_PROC_LOCK_MAIN;
-	    erts_deliver_exit_message(BIF_ARG_1, BIF_P, &locks, am_noproc, NIL);
-	    erts_proc_unlock(BIF_P, ~ERTS_PROC_LOCK_MAIN & locks);
-	    BIF_RET(am_true);
-	}
-	else
-	    BIF_ERROR(BIF_P, EXC_NOPROC);
+res_no_proc:
+    if (BIF_P->flags & F_TRAP_EXIT) {
+        ErtsProcLocks locks = ERTS_PROC_LOCK_MAIN;
+        erts_deliver_exit_message(BIF_ARG_1, BIF_P, &locks, am_noproc, NIL);
+        erts_proc_unlock(BIF_P, ~ERTS_PROC_LOCK_MAIN & locks);
+        BIF_RET(am_true);
+    }
+    else {
+        /*
+         * This behaviour is *really* sad but link/1 has
+         * behaved like this for ages (and this behaviour is
+         * actually documented)... :'-(
+         *
+         * The proper behavior would have been to
+         * send calling process an exit signal..
+         */
+        BIF_ERROR(BIF_P, EXC_NOPROC);
     }
 }
 
-/* This function is allowed to return range of values handled by demonitor/1-2
- * Namely: atoms true, false, yield, internal_error, badarg or THE_NON_VALUE
- */
 static Eterm
-remote_demonitor(Process *c_p, DistEntry *dep, Eterm ref, Eterm to)
+demonitor(Process *c_p, Eterm ref, Eterm *multip)
 {
-    ErtsDSigData dsd;
-    ErtsMonitor *dmon;
-    ErtsMonitor *mon;
-    int code;
-    Eterm res = am_false;
-
-    ERTS_LC_ASSERT((ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_LINK)
-		       == erts_proc_lc_my_proc_locks(c_p));
+    ErtsMonitor  *mon;  /* The monitor entry to delete */
 
-    code = erts_dsig_prepare(&dsd, dep, c_p, ERTS_PROC_LOCK_MAIN,
-			     ERTS_DSP_RLOCK, 0, 0);
-    switch (code) {
-    case ERTS_DSIG_PREP_NOT_ALIVE:
-    case ERTS_DSIG_PREP_NOT_CONNECTED:
-	/*
-	 * In the smp case this is possible if the node goes
-	 * down just before the call to demonitor.
-	 */
-	if (dep) {
-	    erts_de_links_lock(dep);
-	    dmon = erts_remove_monitor(&dep->monitors, ref);
-	    erts_de_links_unlock(dep);
-	    if (dmon)
-		erts_destroy_monitor(dmon);
-	}
-	mon = erts_remove_monitor(&ERTS_P_MONITORS(c_p), ref);
-	erts_proc_unlock(c_p, ERTS_PROC_LOCK_LINK);
-
-        res = am_true;
-	break;
-
-    case ERTS_DSIG_PREP_PENDING:
-    case ERTS_DSIG_PREP_CONNECTED:
-
-	erts_de_links_lock(dep);
-	mon = erts_remove_monitor(&ERTS_P_MONITORS(c_p), ref);
-	dmon = erts_remove_monitor(&dep->monitors, ref);
-	erts_de_links_unlock(dep);
-	erts_de_runlock(dep);
-	erts_proc_unlock(c_p, ERTS_PROC_LOCK_LINK);
-
-	if (!dmon) {
-	    /*
-	     * This is possible when smp support is enabled.
-	     * 'DOWN' message just arrived.
-	     */
-            res = am_true;
-	}
-	else {
-	    /*
-	     * Soft (no force) send, use ->data in dist slot 
-	     * monitor list since in case of monitor name 
-	     * the atom is stored there. Yield if necessary.
-	     */
-	    code = erts_dsig_send_demonitor(&dsd,
-					    c_p->common.id, 
-					    (mon->name != NIL
-					     ? mon->name
-					     : mon->u.pid), 
-					    ref,
-					    0);
-            res = (code == ERTS_DSIG_SEND_YIELD ? am_yield : am_true);
-	    erts_destroy_monitor(dmon);
-	}
-	break;
-    default:
-	ERTS_ASSERT(! "Invalid dsig prepare result");
-    }
-
-
-    /*
-     * We aren't allowed to destroy 'mon' until now, since 'to'
-     * may refer into 'mon' (external pid).
-     */
-    ASSERT(mon); /* Since link lock wasn't released between
-		    lookup and remove */
-    erts_destroy_monitor(mon);
-
-    ERTS_LC_ASSERT(ERTS_PROC_LOCK_MAIN == erts_proc_lc_my_proc_locks(c_p));
-    return res;
-}
+   *multip = am_false;
 
-static ERTS_INLINE void
-demonitor_local_process(Process *c_p, Eterm ref, Eterm to, Eterm *res)
-{
-    Process *rp = erts_pid2proc_opt(c_p,
-                           ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_LINK,
-                           to,
-                           ERTS_PROC_LOCK_LINK,
-                           ERTS_P2P_FLG_ALLOW_OTHER_X);
-    ErtsMonitor *mon = erts_remove_monitor(&ERTS_P_MONITORS(c_p), ref);
+   if (is_not_internal_ref(ref)) {
+       if (is_external_ref(ref)
+           && (erts_this_dist_entry
+               == external_ref_dist_entry(ref))) {
+           return am_false;
+       }
+       return am_badarg; /* Not monitored by this monitor's ref */
+   }
 
-    if (!mon)
-        *res = am_false;
-    else
-    {
-        *res = am_true;
-        erts_destroy_monitor(mon);
-    }
-    if (rp) {
-        ErtsMonitor *rmon;
-        rmon = erts_remove_monitor(&ERTS_P_MONITORS(rp), ref);
-        if (rp != c_p)
-            erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-        if (rmon != NULL)
-            erts_destroy_monitor(rmon);
-    }
-    else {
-        ERTS_ASSERT_IS_NOT_EXITING(c_p);
-    }
-}
+   mon = erts_monitor_tree_lookup(ERTS_P_MONITORS(c_p), ref);
+   if (!mon)
+       return am_false;
 
-static ERTS_INLINE BIF_RETTYPE
-demonitor_local_port(Process *origin, Eterm ref, Eterm target)
-{
-    BIF_RETTYPE res = am_false;
-    Port        *port = erts_port_lookup_raw(target);
+   if (!erts_monitor_is_origin(mon))
+       return am_badarg;
 
-    if (!port) {
-        BIF_ERROR(origin, BADARG);
-    }
-    erts_proc_unlock(origin, ERTS_PROC_LOCK_LINK);
+   erts_monitor_tree_delete(&ERTS_P_MONITORS(c_p), mon);
 
-    if (port) {
-        Eterm trap_ref;
-        switch (erts_port_demonitor(origin, ERTS_PORT_DEMONITOR_NORMAL,
-                                    port, ref, &trap_ref)) {
-        case ERTS_PORT_OP_DROPPED:
-        case ERTS_PORT_OP_BADARG:
-            break;
-        case ERTS_PORT_OP_SCHEDULED:
-            BIF_TRAP3(await_port_send_result_trap, origin, trap_ref,
-                      am_busy_port, am_true);
-            /* the busy_port atom will never be returned, because it cannot be
-             * returned from erts_port_(de)monitor, but just in case if in future
-             * internal API changes - you may see this atom */
-        default:
-            break;
-        }
-    }
-    else {
-        ERTS_ASSERT_IS_NOT_EXITING(origin);
-    }
-    BIF_RET(res);
-}
+   switch (mon->type) {
 
-/* Can return atom true, false, yield, internal_error, badarg or
- * THE_NON_VALUE if error occurred or trap has been set up
- */
-static
-BIF_RETTYPE demonitor(Process *c_p, Eterm ref, Eterm *multip)
-{
-   ErtsMonitor  *mon = NULL;  /* The monitor entry to delete */
-   Eterm        to = NIL;     /* Monitor link traget */
-   DistEntry    *dep = NULL;  /* Target's distribution entry */
-   BIF_RETTYPE  res = am_false;
-   int          unlock_link = 1;
+   case ERTS_MON_TYPE_TIME_OFFSET:
+       *multip = am_true;
+       erts_demonitor_time_offset(mon);
+       return am_true;
+
+   case ERTS_MON_TYPE_PORT: {
+       Port *prt;
+       ASSERT(is_internal_port(mon->other.item));
+       prt = erts_port_lookup(mon->other.item, ERTS_PORT_SFLGS_DEAD);
+       if (!prt || erts_port_demonitor(c_p, prt, mon) == ERTS_PORT_OP_DROPPED)
+           erts_monitor_release(mon);
+       return am_true;
+   }
 
-   erts_proc_lock(c_p, ERTS_PROC_LOCK_LINK);
+   case ERTS_MON_TYPE_PROC:
+       erts_proc_sig_send_demonitor(mon);
+       return am_true;
 
-   if (is_not_internal_ref(ref)) {
-       res = am_badarg;
-       goto done; /* Cannot be this monitor's ref */
-   }
+   case ERTS_MON_TYPE_DIST_PROC: {
+       ErtsMonitorData *mdp = erts_monitor_to_data(mon);
+       Eterm to = mon->other.item;
+       DistEntry *dep;
+       int code = ERTS_DSIG_SEND_OK;
+       int deleted;
+       ErtsDSigData dsd;
 
-   mon = erts_lookup_monitor(ERTS_P_MONITORS(c_p), ref);
-   if (!mon) {
-       goto done;
-   }
+       ASSERT(is_external_pid(to) || is_node_name_atom(to));
 
-   switch (mon->type) {
-   case MON_TIME_OFFSET:
-       *multip = am_true;
-       erts_demonitor_time_offset(ref);
-       res = am_true;
-       break;
-   case MON_ORIGIN:
-       to = mon->u.pid;
-       *multip = am_false;
-       if (is_atom(to)) {
+       if (is_external_pid(to))
+           dep = external_pid_dist_entry(to);
+       else {
            /* Monitoring a name at node to */
-           ASSERT(is_node_name_atom(to));
            dep = erts_sysname_to_connected_dist_entry(to);
            ASSERT(dep != erts_this_dist_entry);
-       } else if (is_port(to)) {
-           if (port_dist_entry(to) != erts_this_dist_entry) {
-               goto badarg;
+           if (!dep) {
+               erts_monitor_release(mon);
+               return am_false;
            }
-           res = demonitor_local_port(c_p, ref, to);
-           unlock_link = 0;
-           goto done;
-       } else {
-           ASSERT(is_pid(to));
-           dep = pid_dist_entry(to);
        }
-       if (dep != erts_this_dist_entry) {
-           res = remote_demonitor(c_p, dep, ref, to);
-           /* remote_demonitor() unlocks link lock on c_p */
-           unlock_link = 0;
+
+       code = erts_dsig_prepare(&dsd, dep, c_p, ERTS_PROC_LOCK_MAIN,
+                                ERTS_DSP_RLOCK, 0, 0);
+
+       deleted = erts_monitor_dist_delete(&mdp->target);
+
+       switch (code) {
+       case ERTS_DSIG_PREP_NOT_ALIVE:
+       case ERTS_DSIG_PREP_NOT_CONNECTED:
+           /*
+            * In the smp case this is possible if the node goes
+            * down just before the call to demonitor.
+            */
+           break;
+
+       case ERTS_DSIG_PREP_PENDING:
+       case ERTS_DSIG_PREP_CONNECTED: {
+           Eterm watched;
+
+           erts_de_runlock(dep);
+
+           if (mon->flags & ERTS_ML_FLG_NAME)
+               watched = ((ErtsMonitorDataExtended *) mdp)->u.name;
+           else
+               watched = to;
+
+           /*
+            * Soft (no force) send, use ->data in dist slot 
+            * monitor list since in case of monitor name 
+            * the atom is stored there. Yield if necessary.
+            */
+           code = erts_dsig_send_demonitor(&dsd, c_p->common.id,
+                                           watched, mdp->ref, 0);
+           break;
        }
-       else { /* Local monitor */
-           demonitor_local_process(c_p, ref, to, &res);
+
+       default:
+           ERTS_INTERNAL_ERROR("invalid result from erts_dsig_prepare()");
+           break;
        }
-       break;
-    default /* case */ :
-badarg:
-       res = am_badarg; /* will be converted to error by caller */
-       *multip = am_false;
-       break;
-   }
-done:
 
-   if (unlock_link)
-       erts_proc_unlock(c_p, ERTS_PROC_LOCK_LINK);
+       if (deleted)
+           erts_monitor_release(&mdp->target);
 
-   ERTS_LC_ASSERT(ERTS_PROC_LOCK_MAIN == erts_proc_lc_my_proc_locks(c_p));
-   BIF_RET(res);
+       erts_monitor_release(mon);
+       return code == ERTS_DSIG_SEND_YIELD ? am_yield : am_true;
+   }
+
+   default:
+       ERTS_INTERNAL_ERROR("Unexpected monitor type");
+       return am_false;
+   }
 }
 
 BIF_RETTYPE demonitor_1(BIF_ALIST_1)
@@ -528,25 +384,23 @@ BIF_RETTYPE demonitor_1(BIF_ALIST_1)
     Eterm multi;
     switch (demonitor(BIF_P, BIF_ARG_1, &multi)) {
     case am_false:
-    case am_true:       BIF_RET(am_true);
-    case THE_NON_VALUE: BIF_RET(THE_NON_VALUE);
-    case am_yield:      ERTS_BIF_YIELD_RETURN(BIF_P, am_true);
-    case am_badarg:     BIF_ERROR(BIF_P, BADARG);
-
-    case am_internal_error:
+    case am_true:
+        BIF_RET(am_true);
+    case am_yield:
+        ERTS_BIF_YIELD_RETURN(BIF_P, am_true);
+    case am_badarg:
     default:
-	ASSERT(! "demonitor(): internal error");
-	BIF_ERROR(BIF_P, EXC_INTERNAL_ERROR);
+        BIF_ERROR(BIF_P, BADARG);
     }
 }
 
 BIF_RETTYPE demonitor_2(BIF_ALIST_2)
 {
-    BIF_RETTYPE res = am_true;
-    Eterm       multi = am_false;
-    int         info = 0;
-    int         flush = 0;
-    Eterm       list = BIF_ARG_2;
+    BIF_RETTYPE res;
+    Eterm multi = am_false;
+    int info = 0;
+    int flush = 0;
+    Eterm list = BIF_ARG_2;
 
     while (is_list(list)) {
 	Eterm* consp = list_val(list);
@@ -566,10 +420,9 @@ BIF_RETTYPE demonitor_2(BIF_ALIST_2)
     if (is_not_nil(list))
 	goto badarg;
 
+    res = am_true;
     switch (demonitor(BIF_P, BIF_ARG_1, &multi)) {
-    case THE_NON_VALUE:
-        /* If other error occurred or trap has been set up - pass through */
-        BIF_RET(THE_NON_VALUE);
+
     case am_false:
 	if (info)
 	    res = am_false;
@@ -578,20 +431,29 @@ flush_messages:
 	    BIF_TRAP3(flush_monitor_messages_trap, BIF_P,
 		      BIF_ARG_1, multi, res);
 	}
+        /* Fall through... */
+
     case am_true:
 	if (multi == am_true && flush)
 	    goto flush_messages;
 	BIF_RET(res);
+
     case am_yield:
-	ERTS_BIF_YIELD_RETURN(BIF_P, am_true);
+        /* return true after yield... */
+        if (flush) {
+            ERTS_VBUMP_ALL_REDS(BIF_P);
+            goto flush_messages;
+        }
+        ERTS_BIF_YIELD_RETURN(BIF_P, am_true);
+
     case am_badarg:
-badarg:
-	BIF_ERROR(BIF_P, BADARG);
-    case am_internal_error:
     default:
-	ASSERT(! "demonitor(): internal error");
-	BIF_ERROR(BIF_P, EXC_INTERNAL_ERROR);
+        break;
+
     }
+
+badarg:
+    BIF_ERROR(BIF_P, BADARG);
 }
 
 /* Type must be atomic object! */
@@ -631,292 +493,212 @@ erts_queue_monitor_message(Process *p,
     erts_queue_message(p, *p_locksp, msgp, tup, am_system);
 }
 
-static Eterm
-local_pid_monitor(Process *p, Eterm target, Eterm mon_ref, int boolean)
+BIF_RETTYPE monitor_2(BIF_ALIST_2)
 {
-    Eterm         ret = mon_ref;
-    Process      *rp;
-    ErtsProcLocks p_locks = ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_LINK;
-
-    if (target == p->common.id) {
-	return ret;
-    }
+    Eterm target = BIF_ARG_2;
+    Eterm tmp_heap[3];
+    Eterm ref, id, name;
+    ErtsMonitorData *mdp;
+
+    if (BIF_ARG_1 == am_process) {
+        DistEntry *dep;
+        int byname;
+
+        if (is_internal_pid(target)) {
+            name = NIL;
+            id = target;
+
+        local_process:
+
+            ref = erts_make_ref(BIF_P);
+            if (id != BIF_P->common.id) {
+                mdp = erts_monitor_create(ERTS_MON_TYPE_PROC,
+                                          ref, BIF_P->common.id,
+                                          id, name);
+                erts_monitor_tree_insert(&ERTS_P_MONITORS(BIF_P),
+                                         &mdp->origin);
+
+                if (!erts_proc_sig_send_monitor(&mdp->target, id))
+                    erts_proc_sig_send_monitor_down(&mdp->target,
+                                                    am_noproc);
+            }
+            BIF_RET(ref);
+        }
 
-    erts_proc_lock(p, ERTS_PROC_LOCK_LINK);
-    rp = erts_pid2proc_opt(p, p_locks,
-			   target, ERTS_PROC_LOCK_LINK,
-			   ERTS_P2P_FLG_ALLOW_OTHER_X);
-    if (!rp) {
-	erts_proc_unlock(p, ERTS_PROC_LOCK_LINK);
-	p_locks &= ~ERTS_PROC_LOCK_LINK;
-	if (boolean)
-	    ret = am_false;
-	else
-	    erts_queue_monitor_message(p, &p_locks,
-				       mon_ref, am_process, target, am_noproc);
-    }
-    else {
-	ASSERT(rp != p);
+        if (is_atom(target)) {
+        local_named_process:
+            name = target;
+            id = erts_whereis_name_to_id(BIF_P, target);
+            if (is_internal_pid(id))
+                goto local_process;
+            target = TUPLE2(&tmp_heap[0], name,
+                            erts_this_dist_entry->sysname);
+            goto noproc;
+        }
 
-	if (boolean)
-	    ret = am_true;
+        if (is_external_pid(target)) {
+            ErtsDSigData dsd;
+            int code;
+
+            dep = external_pid_dist_entry(target);
+            if (dep == erts_this_dist_entry)
+                goto noproc;
+
+            id = target;
+            name = NIL;
+            byname = 0;
+
+        remote_process:
+
+            ref = erts_make_ref(BIF_P);
+            mdp = erts_monitor_create(ERTS_MON_TYPE_DIST_PROC, ref,
+                                      BIF_P->common.id, id, name);
+            erts_monitor_tree_insert(&ERTS_P_MONITORS(BIF_P), &mdp->origin);
+
+            code = erts_dsig_prepare(&dsd, dep,
+                                     BIF_P, ERTS_PROC_LOCK_MAIN,
+                                     ERTS_DSP_RLOCK, 0, 1);
+            switch (code) {
+            case ERTS_DSIG_PREP_NOT_ALIVE:
+            case ERTS_DSIG_PREP_NOT_CONNECTED:
+                erts_monitor_set_dead_dist(&mdp->target, dep->sysname);
+                erts_proc_sig_send_monitor_down(&mdp->target, am_noconnection);
+                code = ERTS_DSIG_SEND_OK;
+                break;
 
-	erts_add_monitor(&ERTS_P_MONITORS(p), MON_ORIGIN, mon_ref, target, NIL);
-	erts_add_monitor(&ERTS_P_MONITORS(rp), MON_TARGET, mon_ref, p->common.id, NIL);
+            case ERTS_DSIG_PREP_PENDING:
+            case ERTS_DSIG_PREP_CONNECTED: {
+#ifdef DEBUG
+                int inserted =
+#endif
 
-	erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-    }
+                erts_monitor_dist_insert(&mdp->target, dep->mld);
+                ASSERT(inserted);
+                erts_de_runlock(dep);
 
-    erts_proc_unlock(p, p_locks & ~ERTS_PROC_LOCK_MAIN);
+                code = erts_dsig_send_monitor(&dsd, BIF_P->common.id, target, ref);
+                break;
+            }
 
-    return ret;
-}
+            default:
+                ERTS_ASSERT(! "Invalid dsig prepare result");
+                code = ERTS_DSIG_SEND_OK;
+                break;
+            }
 
-static BIF_RETTYPE
-local_port_monitor(Process *origin, Eterm target)
-{
-    BIF_RETTYPE ref = erts_make_ref(origin);
-    Port *port = erts_sig_lookup_port(origin, target);
-    ErtsProcLocks p_locks = ERTS_PROC_LOCK_MAIN;
+            if (byname)
+                erts_deref_dist_entry(dep);
 
-    if (!port) {
-res_no_proc:
-        /* Send the DOWN message immediately. Ref is made on the fly because
-         * caller has never seen it yet. */
-        erts_queue_monitor_message(origin, &p_locks, ref,
-                                   am_port, target, am_noproc);
-    }
-    else {
-        switch (erts_port_monitor(origin, port, target, &ref)) {
-        case ERTS_PORT_OP_DROPPED:
-        case ERTS_PORT_OP_BADARG:
-            goto res_no_proc;
-        case ERTS_PORT_OP_SCHEDULED:
-            BIF_TRAP3(await_port_send_result_trap, origin, ref,
-                      am_busy_port, ref);
-            /* the busy_port atom will never be returned, because it cannot be
-             * returned from erts_port_monitor, but just in case if in future
-             * internal API changes - you may see this atom */
-        default:
-            break;
+            if (code == ERTS_DSIG_SEND_YIELD)
+                ERTS_BIF_YIELD_RETURN(BIF_P, ref);
+            BIF_RET(ref);
         }
-    }
-    erts_proc_unlock(origin, p_locks & ~ERTS_PROC_LOCK_MAIN);
-    BIF_RET(ref);
-}
 
-/* Type = process | port :: atom(), 1st argument passed to erlang:monitor/2
- */
-static BIF_RETTYPE
-local_name_monitor(Process *self, Eterm type, Eterm target_name)
-{
-    BIF_RETTYPE ret = erts_make_ref(self);
+        if (is_tuple(target)) {
+            Eterm *tpl = tuple_val(target);
+            if (arityval(tpl[0]) != 2)
+                goto badarg;
+            if (is_not_atom(tpl[1]) || is_not_atom(tpl[2]))
+                goto badarg;
+            if (!erts_is_alive && tpl[2] != am_Noname)
+                goto badarg;
+            target = tpl[1];
+            dep = erts_find_or_insert_dist_entry(tpl[2]);
+            if (dep == erts_this_dist_entry) {
+                erts_deref_dist_entry(dep);
+                goto local_named_process;
+            }
 
-    ErtsProcLocks p_locks = ERTS_PROC_LOCK_MAIN | ERTS_PROC_LOCK_LINK;
-    Process     *proc = NULL;
-    Port        *port = NULL;
+            id = dep->sysname;
+            name = target;
+            byname = 1;
+            goto remote_process;
+        }
 
-    erts_proc_lock(self, ERTS_PROC_LOCK_LINK);
+        /* badarg... */
+    }
+    else if (BIF_ARG_1 == am_port) {
+
+        if (is_internal_port(target)) {
+            Port *prt;
+            name = NIL;
+            id = target;
+        local_port:
+            ref = erts_make_ref(BIF_P);
+            mdp = erts_monitor_create(ERTS_MON_TYPE_PORT, ref,
+                                      BIF_P->common.id, id, name);
+            erts_monitor_tree_insert(&ERTS_P_MONITORS(BIF_P), &mdp->origin);
+            prt = erts_port_lookup(id, ERTS_PORT_SFLGS_INVALID_LOOKUP);
+            if (!prt || erts_port_monitor(BIF_P, prt, &mdp->target) == ERTS_PORT_OP_DROPPED)
+                erts_proc_sig_send_monitor_down(&mdp->target, am_noproc);
+            BIF_RET(ref);
+        }
 
-    erts_whereis_name(self, p_locks, target_name,
-                      &proc, ERTS_PROC_LOCK_LINK,
-                      ERTS_P2P_FLG_ALLOW_OTHER_X,
-                      &port, 0);
+        if (is_atom(target)) {
+        local_named_port:
+            name = target;
+            id = erts_whereis_name_to_id(BIF_P, target);
+            if (is_internal_port(id))
+                goto local_port;
+            target = TUPLE2(&tmp_heap[0], name,
+                            erts_this_dist_entry->sysname);
+            goto noproc;
+        }
 
-    /* If the name is not registered,
-     * or if we asked for proc and got a port,
-     * or if we asked for port and got a proc,
-     * we just send the 'DOWN' message.
-     */
-    if ((!proc && !port) ||
-        (type == am_process && port) ||
-        (type == am_port && proc)) {
-        DeclareTmpHeap(lhp,3,self);
-	Eterm item;
-        UseTmpHeap(3,self);
-
-        erts_proc_unlock(self, ERTS_PROC_LOCK_LINK);
-	p_locks &= ~ERTS_PROC_LOCK_LINK;
-
-	item = TUPLE2(lhp, target_name, erts_this_dist_entry->sysname);
-        erts_queue_monitor_message(self, &p_locks,
-                                   ret,
-                                   type, /* = process|port :: atom() */
-                                   item, am_noproc);
-        UnUseTmpHeap(3,self);
-    }
-    else if (port) {
-        erts_proc_unlock(self, p_locks & ~ERTS_PROC_LOCK_MAIN);
-        p_locks &= ~ERTS_PROC_LOCK_MAIN;
-
-        switch (erts_port_monitor(self, port, target_name, &ret)) {
-        case ERTS_PORT_OP_DONE:
-            return ret;
-        case ERTS_PORT_OP_SCHEDULED: { /* Scheduled a signal */
-            ASSERT(is_internal_ordinary_ref(ret));
-            BIF_TRAP3(await_port_send_result_trap, self,
-                      ret, am_true, ret);
-            /* bif_trap returns */
-        } break;
-        default:
+        if (is_external_port(target)) {
+            if (erts_this_dist_entry == external_port_dist_entry(target))
+                goto noproc;
             goto badarg;
         }
-    }
-    else if (proc != self) {
-        erts_add_monitor(&ERTS_P_MONITORS(self), MON_ORIGIN, ret,
-                         proc->common.id, target_name);
-        erts_add_monitor(&ERTS_P_MONITORS(proc), MON_TARGET, ret,
-                         self->common.id, target_name);
-        erts_proc_unlock(proc, ERTS_PROC_LOCK_LINK);
-    }
-
-    if (p_locks) {
-        erts_proc_unlock(self, p_locks & ~ERTS_PROC_LOCK_MAIN);
-    }
-    BIF_RET(ret);
-badarg:
-    if (p_locks) {
-        erts_proc_unlock(self, p_locks & ~ERTS_PROC_LOCK_MAIN);
-    }
-    BIF_ERROR(self, BADARG);
-}
-
-static BIF_RETTYPE
-remote_monitor(Process *p, Eterm bifarg1, Eterm bifarg2,
-	       DistEntry *dep, Eterm target, int byname)
-{
-    ErtsDSigData dsd;
-    BIF_RETTYPE ret;
-    int code;
 
-    ASSERT(dep);
-    erts_proc_lock(p, ERTS_PROC_LOCK_LINK);
-    code = erts_dsig_prepare(&dsd, dep,
-			     p, (ERTS_PROC_LOCK_MAIN | ERTS_PROC_LOCK_LINK),
-			     ERTS_DSP_RLOCK, 0, 1);
-    switch (code) {
-    case ERTS_DSIG_PREP_NOT_ALIVE:
-    case ERTS_DSIG_PREP_NOT_CONNECTED:
-	erts_proc_unlock(p, ERTS_PROC_LOCK_LINK);
-	ERTS_BIF_PREP_TRAP2(ret, dmonitor_p_trap, p, bifarg1, bifarg2);
-	break;
-    case ERTS_DSIG_PREP_PENDING:
-    case ERTS_DSIG_PREP_CONNECTED:
-	{
-	    Eterm p_trgt, p_name, d_name, mon_ref;
+        if (is_tuple(target)) {
+            Eterm *tpl = tuple_val(target);
+            if (arityval(tpl[0]) != 2)
+                goto badarg;
+            if (is_not_atom(tpl[1]) || is_not_atom(tpl[2]))
+                goto badarg;
+            if (tpl[2] == erts_this_dist_entry->sysname) {
+                target = tpl[1];
+                goto local_named_port;
+            }
+        }
 
-	    mon_ref = erts_make_ref(p);
+        /* badarg... */
+    }
+    else if (BIF_ARG_1 == am_time_offset) {
 
-	    if (byname) {
-		p_trgt = dep->sysname;
-		p_name = target;
-		d_name = target;
-	    }
-	    else {
-		p_trgt = target;
-		p_name = NIL;
-		d_name = NIL;
-	    }
+        if (target != am_clock_service)
+            goto badarg;
+	ref = erts_make_ref(BIF_P);
+        mdp = erts_monitor_create(ERTS_MON_TYPE_TIME_OFFSET,
+                                  ref, BIF_P->common.id,
+                                  am_clock_service, NIL);
+        erts_monitor_tree_insert(&ERTS_P_MONITORS(BIF_P), &mdp->origin);
 
-	    erts_de_links_lock(dep);
+	erts_monitor_time_offset(&mdp->target);
 
-	    erts_add_monitor(&ERTS_P_MONITORS(p), MON_ORIGIN, mon_ref, p_trgt,
-			     p_name);
-	    erts_add_monitor(&(dep->monitors), MON_TARGET, mon_ref, p->common.id,
-			     d_name);
+        BIF_RET(ref);
+    }
 
-	    erts_de_links_unlock(dep);
-	    erts_de_runlock(dep);
-	    erts_proc_unlock(p, ERTS_PROC_LOCK_LINK);
+badarg:
 
-	    code = erts_dsig_send_monitor(&dsd, p->common.id, target, mon_ref);
-	    if (code == ERTS_DSIG_SEND_YIELD)
-		ERTS_BIF_PREP_YIELD_RETURN(ret, p, mon_ref);
-	    else
-		ERTS_BIF_PREP_RET(ret, mon_ref);
-	}
-	break;
-    default:
-	ERTS_ASSERT(! "Invalid dsig prepare result");
-    }
+    BIF_ERROR(BIF_P, BADARG);
 
-    BIF_RET(ret);
-}
-	
-BIF_RETTYPE monitor_2(BIF_ALIST_2)
-{
-    Eterm target = BIF_ARG_2;
-    BIF_RETTYPE ret;
-    DistEntry  *dep = NULL; 
+noproc: {
+        ErtsProcLocks locks = ERTS_PROC_LOCK_MAIN;
 
-    /* Only process monitors are implemented */
-    switch (BIF_ARG_1) {
-    case am_time_offset: {
-	Eterm ref;
-        if (BIF_ARG_2 != am_clock_service) {
-            goto badarg;
-        }
-	ref = erts_make_ref(BIF_P);
-	erts_proc_lock(BIF_P, ERTS_PROC_LOCK_LINK);
-	erts_add_monitor(&ERTS_P_MONITORS(BIF_P), MON_TIME_OFFSET,
-			 ref, am_clock_service, NIL);
-	erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_LINK);
-	erts_monitor_time_offset(BIF_P->common.id, ref);
-	BIF_RET(ref);
-    }
-    case am_process:
-    case am_port:
-	break;
-    default:
-        goto badarg;
-    }
+        ref = erts_make_ref(BIF_P);
+        erts_queue_monitor_message(BIF_P,
+                                   &locks,
+                                   ref,
+                                   BIF_ARG_1,
+                                   target,
+                                   am_noproc);
+        if (locks != ERTS_PROC_LOCK_MAIN)
+            erts_proc_unlock(BIF_P, locks & ~ERTS_PROC_LOCK_MAIN);
 
-    if (is_internal_pid(target) && BIF_ARG_1 == am_process) {
-local_pid:
-        ret = local_pid_monitor(BIF_P, target, erts_make_ref(BIF_P), 0);
-    } else if (is_external_pid(target) && BIF_ARG_1 == am_process) {
-	dep = external_pid_dist_entry(target);
-	if (dep == erts_this_dist_entry)
-	    goto local_pid;
-	ret = remote_monitor(BIF_P, BIF_ARG_1, BIF_ARG_2, dep, target, 0);
-    } else if (is_internal_port(target) && BIF_ARG_1 == am_port) {
-local_port:
-        ret = local_port_monitor(BIF_P, target);
-    } else if (is_external_port(target) && BIF_ARG_1 == am_port) {
-        dep = external_port_dist_entry(target);
-        if (dep == erts_this_dist_entry) {
-            goto local_port;
-        }
-        goto badarg; /* No want remote port */
-    } else if (is_atom(target)) {
-        ret = local_name_monitor(BIF_P, BIF_ARG_1, target);
-    } else if (is_tuple(target)) {
-	Eterm *tp = tuple_val(target);
-	Eterm remote_node;
-	Eterm name;
-        if (arityval(*tp) != 2) {
-            goto badarg;
-        }
-	remote_node = tp[2];
-	name = tp[1];
-	if (!is_atom(remote_node) || !is_atom(name)) {
-            goto badarg;
-	}
-	if (!erts_is_alive && remote_node != am_Noname) {
-            goto badarg; /* Remote monitor from (this) undistributed node */
-	}
-	dep = erts_find_or_insert_dist_entry(remote_node);
-	if (dep == erts_this_dist_entry) {
-            ret = local_name_monitor(BIF_P, BIF_ARG_1, name);
-	} else {
-	    ret = remote_monitor(BIF_P, BIF_ARG_1, BIF_ARG_2, dep, name, 1);
-	}
-	erts_deref_dist_entry(dep);
-    } else {
-badarg:
-	ERTS_BIF_PREP_ERROR(ret, BIF_P, BADARG);
+        BIF_RET(ref);
     }
-    return ret;
 }
 
 /**********************************************************************/
@@ -1089,91 +871,74 @@ BIF_RETTYPE spawn_opt_1(BIF_ALIST_1)
 /* remove a link from a process */
 BIF_RETTYPE unlink_1(BIF_ALIST_1)
 {
-    Process *rp;
-    DistEntry *dep;
-    ErtsLink *l = NULL, *rl = NULL;
-    ErtsProcLocks cp_locks = ERTS_PROC_LOCK_MAIN;
-
-    /*
-     * SMP specific note concerning incoming exit signals:
-     *   We have to have at least the status lock during removal of
-     *   the link half on current process, and check for and handle
-     *   a present pending exit while the status lock is held. This
-     *   in order to ensure that we wont be exited by a link after
-     *   it has been removed.
-     *
-     *   (We also have to have the link lock, of course, in order to
-     *    be allowed to remove the link...)
-     */
-
     if (IS_TRACED_FL(BIF_P, F_TRACE_PROCS)) {
-	trace_proc(BIF_P, cp_locks, BIF_P, am_unlink, BIF_ARG_1);
+        trace_proc(BIF_P, ERTS_PROC_LOCK_MAIN,
+                   BIF_P, am_unlink, BIF_ARG_1);
     }
 
-    if (is_internal_port(BIF_ARG_1)) {
-	erts_proc_lock(BIF_P, ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCK_STATUS);
-	if (ERTS_PROC_PENDING_EXIT(BIF_P))
-	    goto handle_pending_exit;
-
-	l = erts_remove_link(&ERTS_P_LINKS(BIF_P), BIF_ARG_1);
+    if (is_internal_pid(BIF_ARG_1)) {
+        ErtsLink *lnk = erts_link_tree_lookup(ERTS_P_LINKS(BIF_P), BIF_ARG_1);
+        if (lnk) {
+            erts_link_tree_delete(&ERTS_P_LINKS(BIF_P), lnk);
+            erts_proc_sig_send_unlink(BIF_P, lnk);
+        }
+        BIF_RET(am_true);
+    }
 
-	erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCK_STATUS);
+    if (is_internal_port(BIF_ARG_1)) {
+        ErtsLink *lnk = erts_link_tree_lookup(ERTS_P_LINKS(BIF_P), BIF_ARG_1);
 
-	if (l) {
+	if (lnk) {
+            Eterm ref;
+            Eterm *refp = erts_port_synchronous_ops ? &ref : NULL;
+            ErtsPortOpResult res = ERTS_PORT_OP_DROPPED;
 	    Port *prt;
 
-	    erts_destroy_link(l);
+            erts_link_tree_delete(&ERTS_P_LINKS(BIF_P), lnk);
 
 	    /* Send unlink signal */
 	    prt = erts_port_lookup(BIF_ARG_1, ERTS_PORT_SFLGS_DEAD);
 	    if (prt) {
-		ErtsPortOpResult res;
-		Eterm ref;
-		Eterm *refp = erts_port_synchronous_ops ? &ref : NULL;
 #ifdef DEBUG
 		ref = NIL;
 #endif
-		res = erts_port_unlink(BIF_P, prt, BIF_P->common.id, refp);
+		res = erts_port_unlink(BIF_P, prt, lnk, refp);
 
-		if (refp && res == ERTS_PORT_OP_SCHEDULED) {
-		    ASSERT(is_internal_ordinary_ref(ref));
-		    BIF_TRAP3(await_port_send_result_trap, BIF_P, ref, am_true, am_true);
-		}
 	    }
+
+            if (res == ERTS_PORT_OP_DROPPED)
+                erts_link_release(lnk);
+            else if (refp && res == ERTS_PORT_OP_SCHEDULED) {
+                ASSERT(is_internal_ordinary_ref(ref));
+                BIF_TRAP3(await_port_send_result_trap, BIF_P, ref, am_true, am_true);
+            }
 	}
 
 	BIF_RET(am_true);
     }
-    else if (is_external_port(BIF_ARG_1)
-	     && external_port_dist_entry(BIF_ARG_1) == erts_this_dist_entry) {
-	BIF_RET(am_true);
-    }
-
-    if (is_not_pid(BIF_ARG_1))
-	BIF_ERROR(BIF_P, BADARG);
 
     if (is_external_pid(BIF_ARG_1)) {
-	ErtsDistLinkData dld;
+        ErtsLink *lnk, *dlnk;
+        ErtsLinkData *ldp;
+        DistEntry *dep;
 	int code;
 	ErtsDSigData dsd;
-	/* Blind removal, we might have trapped or anything, this leaves
-	   us in a state where monitors might be inconsistent, but the dist
-	   code should take care of it. */
-	erts_proc_lock(BIF_P, ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCK_STATUS);
-	if (ERTS_PROC_PENDING_EXIT(BIF_P))
-	    goto handle_pending_exit;
-	l = erts_remove_link(&ERTS_P_LINKS(BIF_P), BIF_ARG_1);
-
-	erts_proc_unlock(BIF_P,
-			     ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCK_STATUS);
-
-	if (l)
-	    erts_destroy_link(l);
 
 	dep = external_pid_dist_entry(BIF_ARG_1);
-	if (dep == erts_this_dist_entry) {
+	if (dep == erts_this_dist_entry)
 	    BIF_RET(am_true);
-	}
+
+        lnk = erts_link_tree_lookup(ERTS_P_LINKS(BIF_P), BIF_ARG_1);
+        if (!lnk)
+            BIF_RET(am_true);
+
+        erts_link_tree_delete(&ERTS_P_LINKS(BIF_P), lnk);
+        dlnk = erts_link_to_other(lnk, &ldp);
+
+        if (erts_link_dist_delete(dlnk))
+            erts_link_release_both(ldp);
+        else
+            erts_link_release(lnk);
 
 	code = erts_dsig_prepare(&dsd, dep, BIF_P, ERTS_PROC_LOCK_MAIN,
 				 ERTS_DSP_NO_LOCK, 0, 0);
@@ -1181,74 +946,27 @@ BIF_RETTYPE unlink_1(BIF_ALIST_1)
 	case ERTS_DSIG_PREP_NOT_ALIVE:
 	case ERTS_DSIG_PREP_NOT_CONNECTED:
 	    BIF_RET(am_true);
-
 	case ERTS_DSIG_PREP_PENDING:
 	case ERTS_DSIG_PREP_CONNECTED:
-	    erts_remove_dist_link(&dld, BIF_P->common.id, BIF_ARG_1, dep);
 	    code = erts_dsig_send_unlink(&dsd, BIF_P->common.id, BIF_ARG_1);
-	    erts_destroy_dist_link(&dld);
 	    if (code == ERTS_DSIG_SEND_YIELD)
 		ERTS_BIF_YIELD_RETURN(BIF_P, am_true);
-	    BIF_RET(am_true);
-
+            break;
 	default:
 	    ASSERT(! "Invalid dsig prepare result");
 	    BIF_ERROR(BIF_P, EXC_INTERNAL_ERROR);
 	}
-    }
-
-    /* Internal pid... */
-
-    erts_proc_lock(BIF_P, ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCK_STATUS);
-
-    cp_locks |= ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCK_STATUS;
-
-    /* get process struct */
-    rp = erts_pid2proc_opt(BIF_P, cp_locks,
-			   BIF_ARG_1, ERTS_PROC_LOCK_LINK,
-			   ERTS_P2P_FLG_ALLOW_OTHER_X);
-
-    if (ERTS_PROC_PENDING_EXIT(BIF_P)) {
-	if (rp && rp != BIF_P)
-	    erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-	goto handle_pending_exit;
-    }
-
-    /* unlink and ignore errors */
-    l = erts_remove_link(&ERTS_P_LINKS(BIF_P), BIF_ARG_1);
-    if (l != NULL)
-	erts_destroy_link(l);
 
-    if (!rp) {
-	ERTS_ASSERT_IS_NOT_EXITING(BIF_P);
+        BIF_RET(am_true);
     }
-    else {
-	rl = erts_remove_link(&ERTS_P_LINKS(rp), BIF_P->common.id);
-	if (rl != NULL)
-	    erts_destroy_link(rl);
-
-	if (IS_TRACED_FL(rp, F_TRACE_PROCS) && rl != NULL) {
-            erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_STATUS);
-            cp_locks &= ~ERTS_PROC_LOCK_STATUS;
-	    trace_proc(BIF_P, (ERTS_PROC_LOCK_MAIN | ERTS_PROC_LOCK_LINK),
-                       rp, am_getting_unlinked, BIF_P->common.id);
-	}
 
-	if (rp != BIF_P)
-	    erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
+    if (is_external_port(BIF_ARG_1)) {
+        if (external_port_dist_entry(BIF_ARG_1) == erts_this_dist_entry)
+            BIF_RET(am_true);
+        /* Links to Remote ports not supported... */
     }
- 
-    erts_proc_unlock(BIF_P, cp_locks & ~ERTS_PROC_LOCK_MAIN);
 
-    BIF_RET(am_true);
-
- handle_pending_exit:
-    erts_handle_pending_exit(BIF_P, (ERTS_PROC_LOCK_MAIN
-				     | ERTS_PROC_LOCK_LINK
-				     | ERTS_PROC_LOCK_STATUS));
-    ASSERT(ERTS_PROC_IS_EXITING(BIF_P)); 
-    erts_proc_unlock(BIF_P,	ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCK_STATUS);
-    ERTS_BIF_EXITED(BIF_P);
+    BIF_ERROR(BIF_P, BADARG);
 }
 
 BIF_RETTYPE hibernate_3(BIF_ALIST_3)
@@ -1493,22 +1211,69 @@ BIF_RETTYPE raise_3(BIF_ALIST_3)
     return am_badarg;
 }
 
+static BIF_RETTYPE
+erts_internal_await_exit_trap(BIF_ALIST_0)
+{
+    /*
+     * We have sent ourselves an exit signal which will
+     * terminate ourselves. Handle all signals until
+     * terminated in order to ensure that signal order
+     * is preserved. Yield if necessary.
+     */
+    erts_aint32_t state;
+    int reds = ERTS_BIF_REDS_LEFT(BIF_P);
+    (void) erts_proc_sig_handle_incoming(BIF_P, &state, &reds,
+                                         reds, !0);
+    BUMP_REDS(BIF_P, reds);
+    if (state & ERTS_PSFLG_EXITING)
+        ERTS_BIF_EXITED(BIF_P);
+
+    ERTS_BIF_YIELD0(&await_exit_trap, BIF_P);
+}
+
 /**********************************************************************/
-/* send an exit message to another process (if trapping exits) or
-   exit the other process */
+/* send an exit signal to another process */
 
-BIF_RETTYPE exit_2(BIF_ALIST_2)
+static BIF_RETTYPE send_exit_signal_bif(Process *c_p, Eterm id, Eterm reason, int exit2)
 {
-     Process *rp;
+    BIF_RETTYPE ret_val;
 
-     /*
-      * If the first argument is not a pid, or a local port it is an error.
-      */
+    /*
+     * 'id' not a process id, nor a local port id is a 'badarg' error.
+     */
 
-     if (is_internal_port(BIF_ARG_1)) {
+     if (is_internal_pid(id)) {
+         /*
+          * Preserve the very old and *very strange* behaviour
+          * of erlang:exit/2...
+          *
+          * - terminate ourselves even though exit reason
+          *   is normal (unless we trap exit)
+          * - terminate ourselves before exit/2 return
+          */
+         int exit2_suicide = (exit2
+                              && c_p->common.id == id
+                              && (reason == am_kill
+                                  || !(c_p->flags & F_TRAP_EXIT)));
+         erts_proc_sig_send_exit(c_p, c_p->common.id, id,
+                                 reason, NIL, exit2_suicide);
+         if (!exit2_suicide)
+             ERTS_BIF_PREP_RET(ret_val, am_true);
+         else {
+             erts_proc_lock(c_p, ERTS_PROC_LOCK_MSGQ);
+             erts_proc_sig_fetch(c_p);
+             erts_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ);
+             ERTS_BIF_PREP_TRAP0(ret_val, &await_exit_trap, c_p);
+         }
+     }
+     else if (is_internal_port(id)) {
 	 Eterm ref, *refp;
 	 Uint32 invalid_flags;
 	 Port *prt;
+         ErtsPortOpResult res = ERTS_PORT_OP_DONE;
+#ifdef DEBUG
+         ref = NIL;
+#endif
 
 	 if (erts_port_synchronous_ops) {
 	     refp = &ref;
@@ -1519,108 +1284,75 @@ BIF_RETTYPE exit_2(BIF_ALIST_2)
 	     invalid_flags = ERTS_PORT_SFLGS_INVALID_LOOKUP;
 	 }
 
-	 prt = erts_port_lookup(BIF_ARG_1, invalid_flags);
-
-	 if (prt) {
-	     ErtsPortOpResult res;
-
-#ifdef DEBUG
-	     ref = NIL;
-#endif
-
-	     res = erts_port_exit(BIF_P, 0, prt, BIF_P->common.id, BIF_ARG_2, refp);
-
-	     ERTS_BIF_CHK_EXITED(BIF_P);
-
-	     if (refp && res == ERTS_PORT_OP_SCHEDULED) {
-		 ASSERT(is_internal_ordinary_ref(ref));
-		 BIF_TRAP3(await_port_send_result_trap, BIF_P, ref, am_true, am_true);
-	     }
-
-	 }
-
-	 BIF_RET(am_true);
+	 prt = erts_port_lookup(id, invalid_flags);
+	 if (prt)
+	     res = erts_port_exit(c_p, 0, prt, c_p->common.id, reason, refp);
+
+         if (!refp || res != ERTS_PORT_OP_SCHEDULED)
+             ERTS_BIF_PREP_RET(ret_val, am_true);
+         else {
+             ASSERT(is_internal_ordinary_ref(ref));
+             ERTS_BIF_PREP_TRAP3(ret_val, await_port_send_result_trap,
+                                 c_p, ref, am_true, am_true);
+         }
      }
-     else if(is_external_port(BIF_ARG_1)
-	     && external_port_dist_entry(BIF_ARG_1) == erts_this_dist_entry)
-	 BIF_RET(am_true);
-     
-     /*
-      * If it is a remote pid, send a signal to the remote node.
-      */
-
-     if (is_external_pid(BIF_ARG_1)) {
-	 int code;
-	 ErtsDSigData dsd;
-	 DistEntry *dep;
-
-	 dep = external_pid_dist_entry(BIF_ARG_1);
-	 ERTS_ASSERT(dep);
-	 if(dep == erts_this_dist_entry)
-	     BIF_RET(am_true);
-
-	 code = erts_dsig_prepare(&dsd, dep, BIF_P, ERTS_PROC_LOCK_MAIN,
-				  ERTS_DSP_NO_LOCK, 0, 1);
-	 switch (code) {
-	 case ERTS_DSIG_PREP_NOT_ALIVE:
-	 case ERTS_DSIG_PREP_NOT_CONNECTED:
-	     BIF_RET(am_true);
-	 case ERTS_DSIG_PREP_PENDING:
-	 case ERTS_DSIG_PREP_CONNECTED:
-	     code = erts_dsig_send_exit2(&dsd, BIF_P->common.id, BIF_ARG_1, BIF_ARG_2);
-	     if (code == ERTS_DSIG_SEND_YIELD)
-		 ERTS_BIF_YIELD_RETURN(BIF_P, am_true);
-	     BIF_RET(am_true);
-	 default:
-	     ERTS_ASSERT(! "Invalid dsig prepare result");
-	 }
+     else if (is_external_pid(id)) {
+	 DistEntry *dep = external_pid_dist_entry(id);
+	 if (dep == erts_this_dist_entry)
+             ERTS_BIF_PREP_RET(ret_val, am_true); /* Old incarnation of this node... */
+         else {
+             int code;
+             ErtsDSigData dsd;
+
+             code = erts_dsig_prepare(&dsd, dep, c_p, ERTS_PROC_LOCK_MAIN,
+                                      ERTS_DSP_NO_LOCK, 0, 1);
+             switch (code) {
+             case ERTS_DSIG_PREP_NOT_ALIVE:
+             case ERTS_DSIG_PREP_NOT_CONNECTED:
+                 ERTS_BIF_PREP_RET(ret_val, am_true);
+                 break;
+             case ERTS_DSIG_PREP_PENDING:
+             case ERTS_DSIG_PREP_CONNECTED:
+                 code = erts_dsig_send_exit2(&dsd, c_p->common.id, id, reason);
+                 if (code == ERTS_DSIG_SEND_YIELD)
+                     ERTS_BIF_PREP_YIELD_RETURN(ret_val, c_p, am_true);
+                 else
+                     ERTS_BIF_PREP_RET(ret_val, am_true);
+                 break;
+             default:
+                 ASSERT(! "Invalid dsig prepare result");
+                 ERTS_BIF_PREP_ERROR(ret_val, c_p, EXC_INTERNAL_ERROR);
+                 break;
+             }
+         }
      }
-     else if (is_not_internal_pid(BIF_ARG_1)) {
-       BIF_ERROR(BIF_P, BADARG);
+     else if (is_external_port(id)) {
+	 DistEntry *dep = external_port_dist_entry(id);
+	 if(dep == erts_this_dist_entry)
+             ERTS_BIF_PREP_RET(ret_val, am_true); /* Old incarnation of this node... */
+         else
+             ERTS_BIF_PREP_ERROR(ret_val, c_p, BADARG);
      }
      else {
-	 /*
-	  * The pid is internal.  Verify that it refers to an existing process.
-	  */
-	 ErtsProcLocks rp_locks;
-
-	 if (BIF_ARG_1 == BIF_P->common.id) {
-	     rp_locks = ERTS_PROC_LOCKS_ALL;
-	     rp = BIF_P;
-	     erts_proc_lock(rp, ERTS_PROC_LOCKS_ALL_MINOR);
-	 }
-	 else {
-	     rp_locks = ERTS_PROC_LOCKS_XSIG_SEND;
-	     rp = erts_pid2proc(BIF_P, ERTS_PROC_LOCK_MAIN,
-				BIF_ARG_1, rp_locks);
-	     if (!rp) {
-		 BIF_RET(am_true);
-	     }
-	 }
+         /* Not an id of a process or a port... */
 
-	 /*
-	  * Send an exit signal.
-	  */
-	 erts_send_exit_signal(BIF_P,
-			       BIF_P->common.id,
-			       rp,
-			       &rp_locks,
-			       BIF_ARG_2,
-			       NIL,
-			       NULL,
-			       BIF_P == rp ? ERTS_XSIG_FLG_NO_IGN_NORMAL : 0);
-	 if (rp == BIF_P)
-	     rp_locks &= ~ERTS_PROC_LOCK_MAIN;
-	 if (rp_locks)
-	     erts_proc_unlock(rp, rp_locks);
-	 /*
-	  * We may have exited ourselves and may have to take action.
-	  */
-	 ERTS_BIF_CHK_EXITED(BIF_P);
-	 BIF_RET(am_true);
+         ERTS_BIF_PREP_ERROR(ret_val, c_p, BADARG);
      }
+
+     return ret_val;
 }
 
+BIF_RETTYPE exit_2(BIF_ALIST_2)
+{
+    return send_exit_signal_bif(BIF_P, BIF_ARG_1, BIF_ARG_2, !0);
+}
+
+BIF_RETTYPE exit_signal_2(BIF_ALIST_2)
+{
+    return send_exit_signal_bif(BIF_P, BIF_ARG_1, BIF_ARG_2, 0);
+}
+
+
 /**********************************************************************/
 /* this sets some process info- trapping exits or the error handler */
 
@@ -1709,36 +1441,13 @@ BIF_RETTYPE process_flag_2(BIF_ALIST_2)
        BIF_RET(old_value);
    }
    else if (BIF_ARG_1 == am_trap_exit) {
-       erts_aint32_t state;
-       Uint trap_exit;
-       if (BIF_ARG_2 == am_true) {
-	   trap_exit = 1;
-       } else if (BIF_ARG_2 == am_false) {
-	   trap_exit = 0;
-       } else {
-	   goto error;
-       }
-       /*
-	* NOTE: It is important that we check for pending exit signals
-	*       and handle them before returning if trap_exit is set to
-	*       true. For more info, see implementation of
-	*       erts_send_exit_signal().
-	*/
-       erts_proc_lock(BIF_P, ERTS_PROC_LOCKS_XSIG_SEND);
-       if (trap_exit)
-	   state = erts_atomic32_read_bor_mb(&BIF_P->state,
-						 ERTS_PSFLG_TRAP_EXIT);
+       old_value = (BIF_P->flags & F_TRAP_EXIT) ? am_true : am_false;
+       if (BIF_ARG_2 == am_true)
+           BIF_P->flags |= F_TRAP_EXIT;
+       else if (BIF_ARG_2 == am_false)
+           BIF_P->flags &= ~F_TRAP_EXIT;
        else
-	   state = erts_atomic32_read_band_mb(&BIF_P->state,
-						  ~ERTS_PSFLG_TRAP_EXIT);
-       erts_proc_unlock(BIF_P, ERTS_PROC_LOCKS_XSIG_SEND);
-
-       if (state & ERTS_PSFLG_PENDING_EXIT) {
-	   erts_handle_pending_exit(BIF_P, ERTS_PROC_LOCK_MAIN);
-	   ERTS_BIF_EXITED(BIF_P);
-       }
-
-       old_value = (state & ERTS_PSFLG_TRAP_EXIT) ? am_true : am_false;
+	   goto error;
        BIF_RET(old_value);
    }
    else if (BIF_ARG_1 == am_scheduler) {
@@ -2142,9 +1851,6 @@ do_send(Process *p, Eterm to, Eterm msg, Eterm *refp, ErtsSendContext *ctx)
             }
 
 	    switch (erts_port_command(p, ps_flags, pt, msg, refp)) {
-	    case ERTS_PORT_OP_CALLER_EXIT:
-		/* We are exiting... */
-		return SEND_USER_ERROR;
 	    case ERTS_PORT_OP_BUSY:
 		/* Nothing has been sent */
 		if (ctx->suspend)
@@ -4373,14 +4079,88 @@ BIF_RETTYPE group_leader_0(BIF_ALIST_0)
 }
 
 /**********************************************************************/
-/* arg1 == leader, arg2 == new member */
+/* set group leader */
 
-BIF_RETTYPE group_leader_2(BIF_ALIST_2)
+int
+erts_set_group_leader(Process *proc, Eterm new_gl)
 {
-    Process* new_member;
+    
+    erts_aint32_t state;
 
-    if (is_not_pid(BIF_ARG_1)) {
-	BIF_ERROR(BIF_P, BADARG);
+    ASSERT(is_pid(new_gl));
+
+    state = erts_atomic32_read_nob(&proc->state);
+
+    if (state & ERTS_PSFLG_EXITING)
+        return 0;
+        
+    ERTS_LC_ASSERT(ERTS_PROC_LOCK_MAIN & erts_proc_lc_my_proc_locks(proc));
+
+    if (!(state & ERTS_PSFLG_DIRTY_RUNNING))
+        proc->group_leader = STORE_NC_IN_PROC(proc, new_gl);
+    else {
+        ErlHeapFragment *bp;
+        Eterm *hp;
+        /*
+         * Currently executing on a dirty scheduler,
+         * so we are not allowed to write to its heap.
+         * Store group leader pid in heap fragment.
+         */
+        bp = new_message_buffer(NC_HEAP_SIZE(new_gl));
+        hp = bp->mem;
+        proc->group_leader = STORE_NC(&hp,
+                                            &proc->off_heap,
+                                            new_gl);
+        bp->next = proc->mbuf;
+        proc->mbuf = bp;
+        proc->mbuf_sz += bp->used_size;
+    }
+
+    return !0;
+}
+
+BIF_RETTYPE erts_internal_group_leader_3(BIF_ALIST_3)
+{
+    if (is_not_pid(BIF_ARG_1))
+        BIF_ERROR(BIF_P, BADARG);
+    if (is_not_internal_pid(BIF_ARG_2))
+        BIF_ERROR(BIF_P, BADARG);
+    if (is_not_internal_ref(BIF_ARG_3))
+        BIF_ERROR(BIF_P, BADARG);
+
+    erts_proc_sig_send_group_leader(BIF_P,
+                                    BIF_ARG_2,
+                                    BIF_ARG_1,
+                                    BIF_ARG_3);
+    BIF_RET(am_ok);
+}
+
+BIF_RETTYPE erts_internal_group_leader_2(BIF_ALIST_2)
+{
+    if (is_not_pid(BIF_ARG_1))
+        BIF_RET(am_badarg);
+
+    if (is_internal_pid(BIF_ARG_2)) {
+        Process *rp;
+        int res;
+
+        if (BIF_ARG_2 == BIF_P->common.id)
+            rp = BIF_P;
+        else {
+            rp = erts_try_lock_sig_free_proc(BIF_ARG_2,
+                                             ERTS_PROC_LOCK_MAIN);
+            if (!rp)
+                BIF_RET(am_badarg);
+            if (rp == ERTS_PROC_LOCK_BUSY)
+                BIF_RET(am_false);
+        }
+
+        res = erts_set_group_leader(rp, BIF_ARG_1);
+
+        if (rp != BIF_P)
+            erts_proc_unlock(rp, ERTS_PROC_LOCK_MAIN);
+
+        BIF_RET(res ? am_true : am_badarg);
     }
 
     if (is_external_pid(BIF_ARG_2)) {
@@ -4408,74 +4188,8 @@ BIF_RETTYPE group_leader_2(BIF_ALIST_2)
 	    ERTS_ASSERT(! "Invalid dsig prepare result");
 	}
     }
-    else if (is_internal_pid(BIF_ARG_2)) {
-	int await_x;
-	ErtsProcLocks locks = ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_STATUS;
-	new_member = erts_pid2proc_nropt(BIF_P, ERTS_PROC_LOCK_MAIN,
-					 BIF_ARG_2, locks);
-	if (!new_member)
-	    BIF_ERROR(BIF_P, BADARG);
-
-	if (new_member == ERTS_PROC_LOCK_BUSY)
-	    ERTS_BIF_YIELD2(bif_export[BIF_group_leader_2], BIF_P,
-			    BIF_ARG_1, BIF_ARG_2);
-
-	await_x = (new_member != BIF_P
-		   && ERTS_PROC_PENDING_EXIT(new_member));
-	if (!await_x) {
-	    if (is_immed(BIF_ARG_1))
-		new_member->group_leader = BIF_ARG_1;
-	    else {
-		locks &= ~ERTS_PROC_LOCK_STATUS;
-		erts_proc_unlock(new_member, ERTS_PROC_LOCK_STATUS);
-		if (new_member == BIF_P
-		    || !(erts_atomic32_read_nob(&new_member->state)
-			 & ERTS_PSFLG_DIRTY_RUNNING)) {
-		    new_member->group_leader = STORE_NC_IN_PROC(new_member,
-								BIF_ARG_1);
-		}
-		else {
-		    ErlHeapFragment *bp;
-		    Eterm *hp;
-		    /*
-		     * Other process executing on a dirty scheduler,
-		     * so we are not allowed to write to its heap.
-		     * Store in heap fragment.
-		     */
-
-		    bp = new_message_buffer(NC_HEAP_SIZE(BIF_ARG_1));
-		    hp = bp->mem;
-		    new_member->group_leader = STORE_NC(&hp,
-							&new_member->off_heap,
-							BIF_ARG_1);
-		    bp->next = new_member->mbuf;
-		    new_member->mbuf = bp;
-		    new_member->mbuf_sz += bp->used_size;
-		}
-	    }
-	}
-
-	if (new_member == BIF_P)
-	    locks &= ~ERTS_PROC_LOCK_MAIN;
-	if (locks)
-	    erts_proc_unlock(new_member, locks);
-
-	if (await_x) {
-	    /* Wait for new_member to terminate; then badarg */
-	    Eterm args[2] = {BIF_ARG_1, BIF_ARG_2};
-	    ERTS_BIF_AWAIT_X_APPLY_TRAP(BIF_P,
-					BIF_ARG_2,
-					am_erlang,
-					am_group_leader,
-					args,
-					2);
-	}
 
-	BIF_RET(am_true);
-    }
-    else {
-	BIF_ERROR(BIF_P, BADARG);
-    }
+    BIF_RET(am_badarg);
 }
 
 BIF_RETTYPE system_flag_2(BIF_ALIST_2)    
@@ -4662,7 +4376,6 @@ BIF_RETTYPE system_flag_2(BIF_ALIST_2)
         BIF_RET(ret);
     } else if (BIF_ARG_1 == make_small(1)) {
 	int i, max;
-	ErtsMessage* mp;
 	erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_MAIN);
 	erts_thr_progress_block();
 
@@ -4677,16 +4390,8 @@ BIF_RETTYPE system_flag_2(BIF_ALIST_2)
 #endif
 		p->seq_trace_clock = 0;
 		p->seq_trace_lastcnt = 0;
-		ERTS_MSGQ_MV_INQ2PRIVQ(p);
-		mp = p->msg.first;
-		while(mp != NULL) {
-#ifdef USE_VM_PROBES
-		    ERL_MESSAGE_TOKEN(mp) = (ERL_MESSAGE_DT_UTAG(mp) != NIL) ? am_have_dt_utag : NIL;
-#else
-		    ERL_MESSAGE_TOKEN(mp) = NIL;
-#endif
-		    mp = mp->next;
-		}
+
+                erts_proc_sig_clear_seq_trace_tokens(p);
 	    }
 	}
 
@@ -4949,58 +4654,17 @@ static BIF_RETTYPE bif_return_trap(BIF_ALIST_2)
     BIF_RET(res);
 }
 
-/*
- * NOTE: The erts_bif_prep_await_proc_exit_*() functions are
- * tightly coupled with the implementation of erlang:await_proc_exit/3.
- * The erts_bif_prep_await_proc_exit_*() functions can safely call
- * skip_current_msgq() since they know that erlang:await_proc_exit/3
- * unconditionally will do a monitor and then unconditionally will
- * wait for the corresponding 'DOWN' message in a receive, and no other
- * receive is done before this receive. This optimization removes an
- * unnecessary scan of the currently existing message queue (which
- * can be large). If the erlang:await_proc_exit/3 implementation
- * is changed so that the above isn't true, nasty bugs in later
- * receives, etc, may appear.
- */
-
-static ERTS_INLINE int
-skip_current_msgq(Process *c_p)
-{
-    int res;
-#if defined(ERTS_ENABLE_LOCK_CHECK)
-    erts_proc_lc_chk_only_proc_main(c_p);
-#endif
-
-    erts_proc_lock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
-    if (ERTS_PROC_PENDING_EXIT(c_p)) {
-	KILL_CATCHES(c_p);
-	c_p->freason = EXC_EXIT;
-	res = 0;
-    }
-    else {
-        ERTS_MSGQ_MV_INQ2PRIVQ(c_p);
-	c_p->msg.save = c_p->msg.last;
-	res = 1;
-    }
-    erts_proc_unlock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
-    return res;
-}
-
 void
 erts_bif_prep_await_proc_exit_data_trap(Process *c_p, Eterm pid, Eterm ret)
 {
-    if (skip_current_msgq(c_p)) {
-	ERTS_BIF_PREP_TRAP3_NO_RET(await_proc_exit_trap, c_p, pid, am_data, ret);
-    }
+    ERTS_BIF_PREP_TRAP3_NO_RET(await_proc_exit_trap, c_p, pid, am_data, ret);
 }
 
 void
 erts_bif_prep_await_proc_exit_reason_trap(Process *c_p, Eterm pid)
 {
-    if (skip_current_msgq(c_p)) {
-	ERTS_BIF_PREP_TRAP3_NO_RET(await_proc_exit_trap, c_p,
-			    pid, am_reason, am_undefined);
-    }
+    ERTS_BIF_PREP_TRAP3_NO_RET(await_proc_exit_trap, c_p,
+                               pid, am_reason, am_undefined);
 }
 
 void
@@ -5011,21 +4675,19 @@ erts_bif_prep_await_proc_exit_apply_trap(Process *c_p,
 					 Eterm args[],
 					 int nargs)
 {
+    Eterm term;
+    Eterm *hp;
+    int i;
     ASSERT(is_atom(module) && is_atom(function));
-    if (skip_current_msgq(c_p)) {
-	Eterm term;
-	Eterm *hp;
-	int i;
 
-	hp = HAlloc(c_p, 4+2*nargs);
-	term = NIL;
-	for (i = nargs-1; i >= 0; i--) {
-	    term = CONS(hp, args[i], term);
-	    hp += 2;
-	}
-	term = TUPLE3(hp, module, function, term);
-	ERTS_BIF_PREP_TRAP3_NO_RET(await_proc_exit_trap, c_p, pid, am_apply, term);
+    hp = HAlloc(c_p, 4+2*nargs);
+    term = NIL;
+    for (i = nargs-1; i >= 0; i--) {
+        term = CONS(hp, args[i], term);
+        hp += 2;
     }
+    term = TUPLE3(hp, module, function, term);
+    ERTS_BIF_PREP_TRAP3_NO_RET(await_proc_exit_trap, c_p, pid, am_apply, term);
 }
 
 Export bif_return_trap_export;
@@ -5063,6 +4725,9 @@ void erts_init_bif(void)
 			  am_erts_internal, am_dsend_continue_trap, 1,
 			  dsend_continue_trap_1);
 
+    erts_init_trap_export(&await_exit_trap, am_erts_internal,
+                          am_await_exit, 0, erts_internal_await_exit_trap);
+
     flush_monitor_messages_trap = erts_export_put(am_erts_internal,
 						  am_flush_monitor_messages,
 						  3);
diff --git a/erts/emulator/beam/bif.h b/erts/emulator/beam/bif.h
index a2bc883dbe..dca53686f4 100644
--- a/erts/emulator/beam/bif.h
+++ b/erts/emulator/beam/bif.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1996-2016. All Rights Reserved.
+ * Copyright Ericsson AB 1996-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -306,7 +306,7 @@ do {							\
     (Proc)->freason = TRAP;				\
 } while (0)
 
-#define BIF_TRAP0(p, Trap_) do {		\
+#define BIF_TRAP0(Trap_, p) do {                  \
       (p)->arity = 0;				\
       (p)->i = (BeamInstr*) ((Trap_)->addressv[erts_active_code_ix()]);	\
       (p)->freason = TRAP;			\
@@ -404,7 +404,7 @@ do {									\
 #define ERTS_BIF_YIELD0(TRP, P)						\
 do {									\
     ERTS_VBUMP_ALL_REDS((P));						\
-    BIF_TRAP0((TRP), (P));						\
+    BIF_TRAP0((TRP), (P));                                              \
 } while (0)
 
 #define ERTS_BIF_YIELD1(TRP, P, A0)					\
@@ -428,7 +428,7 @@ do {									\
 #define ERTS_BIF_EXITED(PROC)		\
 do {					\
     KILL_CATCHES((PROC));		\
-    BIF_ERROR((PROC), EXC_EXIT);	\
+    BIF_ERROR((PROC), EXTAG_EXIT);	\
 } while (0)
 
 #define ERTS_BIF_CHK_EXITED(PROC)	\
diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab
index be653ee2a0..93613ac2eb 100644
--- a/erts/emulator/beam/bif.tab
+++ b/erts/emulator/beam/bif.tab
@@ -1,7 +1,7 @@
 #
 # %CopyrightBegin%
 #
-# Copyright Ericsson AB 1996-2017. All Rights Reserved.
+# Copyright Ericsson AB 1996-2018. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -62,6 +62,7 @@ bif erlang:erase/0
 bif erlang:erase/1
 bif erlang:exit/1
 bif erlang:exit/2
+bif erlang:exit_signal/2
 bif erlang:external_size/1
 bif erlang:external_size/2
 gcbif erlang:float/1
@@ -73,7 +74,8 @@ bif erlang:get/0
 bif erlang:get/1
 bif erlang:get_keys/1
 bif erlang:group_leader/0
-bif erlang:group_leader/2
+bif erts_internal:group_leader/2
+bif erts_internal:group_leader/3
 bif erlang:halt/2
 bif erlang:phash/2
 bif erlang:phash2/1
@@ -187,6 +189,8 @@ bif erts_internal:release_literal_area_switch/0
 
 bif erts_internal:scheduler_wall_time/1
 
+bif erts_internal:dirty_process_handle_signals/1
+
 # inet_db support
 bif erlang:port_set_data/2
 bif erlang:port_get_data/1
@@ -435,13 +439,6 @@ bif erts_debug:dirty_io/2
 bif erts_debug:dirty/3
 
 #
-# Monitor testing bif's...
-#
-bif erts_debug:dump_monitors/1
-bif erts_debug:dump_links/1
-
-
-#
 # Lock counter bif's
 #
 bif erts_debug:lcnt_control/2
diff --git a/erts/emulator/beam/break.c b/erts/emulator/beam/break.c
index 3967f7f7fc..4dabac3512 100644
--- a/erts/emulator/beam/break.c
+++ b/erts/emulator/beam/break.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1996-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1996-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -39,6 +39,7 @@
 #include "erl_instrument.h"
 #include "erl_hl_timer.h"
 #include "erl_thr_progress.h"
+#include "erl_proc_sig_queue.h"
 
 /* Forward declarations -- should really appear somewhere else */
 static void process_killer(void);
@@ -107,36 +108,11 @@ process_killer(void)
 		if ((j = sys_get_key(0)) <= 0)
 		    erts_exit(0, "");
 		switch(j) {
-		case 'k': {
-		    ErtsProcLocks rp_locks = ERTS_PROC_LOCKS_XSIG_SEND;
-		    erts_aint32_t state;
-		    erts_proc_inc_refc(rp);
-		    erts_proc_lock(rp, rp_locks);
-		    state = erts_atomic32_read_acqb(&rp->state);
-		    if (state & (ERTS_PSFLG_FREE
-				 | ERTS_PSFLG_EXITING
-				 | ERTS_PSFLG_ACTIVE
-				 | ERTS_PSFLG_ACTIVE_SYS
-				 | ERTS_PSFLG_IN_RUNQ
-				 | ERTS_PSFLG_RUNNING
-				 | ERTS_PSFLG_RUNNING_SYS
-				 | ERTS_PSFLG_DIRTY_RUNNING
-				 | ERTS_PSFLG_DIRTY_RUNNING_SYS)) {
-			erts_printf("Can only kill WAITING processes this way\n");
-		    }
-		    else {
-			(void) erts_send_exit_signal(NULL,
-						     NIL,
-						     rp,
-						     &rp_locks,
-						     am_kill,
-						     NIL,
-						     NULL,
-						     0);
-		    }
-		    erts_proc_unlock(rp, rp_locks);
-		    erts_proc_dec_refc(rp);
-		}
+		case 'k':
+                    /* Send a 'kill' exit signal from init process */
+                    erts_proc_sig_send_exit(NULL, erts_init_process_id,
+                                            rp->common.id, am_kill, NIL,
+                                            0);
 		case 'n': br = 1; break;
 		case 'r': return;
 		default: return;
@@ -161,47 +137,64 @@ static void doit_print_link(ErtsLink *lnk, void *vpcontext)
 
     if (pcontext->is_first) {
 	pcontext->is_first = 0;
-	erts_print(to, to_arg, "%T", lnk->pid);
+	erts_print(to, to_arg, "%T", lnk->other.item);
     } else {
-	erts_print(to, to_arg, ", %T", lnk->pid);
+	erts_print(to, to_arg, ", %T", lnk->other.item);
     }
 }
     
 
 static void doit_print_monitor(ErtsMonitor *mon, void *vpcontext)
 {
+    ErtsMonitorData *mdp;
     PrintMonitorContext *pcontext = vpcontext;
     fmtfn_t to = pcontext->to;
     void *to_arg = pcontext->to_arg;
     char *prefix = ", ";
  
-    if (pcontext->is_first) {
-	pcontext->is_first = 0;
-	prefix = "";
-    }
-
+    mdp = erts_monitor_to_data(mon);
     switch (mon->type) {
-    case MON_ORIGIN:
-	if (is_atom(mon->u.pid)) { /* dist by name */
-	    ASSERT(is_node_name_atom(mon->u.pid));
-	    erts_print(to, to_arg, "%s{to,{%T,%T},%T}", prefix, mon->name,
-		       mon->u.pid, mon->ref);
-	} else if (is_atom(mon->name)){ /* local by name */
-	    erts_print(to, to_arg, "%s{to,{%T,%T},%T}", prefix, mon->name,
-		       erts_this_dist_entry->sysname, mon->ref);
-	} else { /* local and distributed by pid */
-	    erts_print(to, to_arg, "%s{to,%T,%T}", prefix, mon->u.pid, mon->ref);
-	}
-	break;
-    case MON_TARGET:
-	erts_print(to, to_arg, "%s{from,%T,%T}", prefix, mon->u.pid, mon->ref);
-	break;
-    case MON_NIF_TARGET: {
-        ErtsResource* rsrc = mon->u.resource;
-        erts_print(to, to_arg, "%s{from,{%T,%T},%T}", prefix, rsrc->type->module,
-                   rsrc->type->name, mon->ref);
-	break;
-    }
+    case ERTS_MON_TYPE_PROC:
+    case ERTS_MON_TYPE_PORT:
+    case ERTS_MON_TYPE_TIME_OFFSET:
+    case ERTS_MON_TYPE_DIST_PROC:
+    case ERTS_MON_TYPE_RESOURCE:
+    case ERTS_MON_TYPE_NODE:
+
+        if (pcontext->is_first) {
+            pcontext->is_first = 0;
+            prefix = "";
+        }
+
+        if (erts_monitor_is_target(mon)) {
+            if (mon->type != ERTS_MON_TYPE_RESOURCE)
+                erts_print(to, to_arg, "%s{from,%T,%T}", prefix, mon->other.item, mdp->ref);
+            else {
+                ErtsResource* rsrc = mon->other.ptr;
+                erts_print(to, to_arg, "%s{from,{%T,%T},%T}", prefix, rsrc->type->module,
+                           rsrc->type->name, mdp->ref);
+            }
+        }
+        else {
+            if (!(mon->flags & ERTS_ML_FLG_NAME))
+                erts_print(to, to_arg, "%s{to,%T,%T}", prefix, mon->other.item, mdp->ref);
+            else {
+                ErtsMonitorDataExtended *mdep = (ErtsMonitorDataExtended *) mdp;
+                Eterm node;
+                if (mdep->dist)
+                    node = mdep->dist->nodename;
+                else
+                    node = erts_this_dist_entry->sysname;
+                erts_print(to, to_arg, "%s{to,{%T,%T},%T}", prefix, mdep->u.name,
+                           node, mdp->ref);
+            }
+        }
+
+        break;
+
+    default:
+        /* ignore other monitors... */
+        break;
     }
 }
 			       
@@ -257,15 +250,22 @@ print_process_info(fmtfn_t to, void *to_arg, Process *p)
     }
 
     erts_print(to, to_arg, "Spawned by: %T\n", p->parent);
-    ERTS_MSGQ_MV_INQ2PRIVQ(p);
-    erts_print(to, to_arg, "Message queue length: %d\n", p->msg.len);
+
+    erts_proc_lock(p, ERTS_PROC_LOCK_MSGQ);
+    erts_proc_sig_fetch(p);
+    erts_proc_unlock(p, ERTS_PROC_LOCK_MSGQ);
+    erts_print(to, to_arg, "Message queue length: %d\n", p->sig_qs.len);
 
     /* display the message queue only if there is anything in it */
-    if (!ERTS_IS_CRASH_DUMPING && p->msg.first != NULL && !garbing) {
-	ErtsMessage* mp;
+    if (!ERTS_IS_CRASH_DUMPING && p->sig_qs.first != NULL && !garbing) {
 	erts_print(to, to_arg, "Message queue: [");
-	for (mp = p->msg.first; mp; mp = mp->next)
-	    erts_print(to, to_arg, mp->next ? "%T," : "%T", ERL_MESSAGE_TERM(mp));
+        ERTS_FOREACH_SIG_PRIVQS(
+            p, mp,
+            {
+                if (ERTS_SIG_IS_NON_MSG((ErtsSignal *) mp))
+                    erts_print(to, to_arg, mp->next ? "%T," : "%T",
+                               ERL_MESSAGE_TERM(mp));
+            });
 	erts_print(to, to_arg, "]\n");
     }
 
@@ -306,11 +306,12 @@ print_process_info(fmtfn_t to, void *to_arg, Process *p)
     }
 
     /* display the links only if there are any*/
-    if (ERTS_P_LINKS(p) || ERTS_P_MONITORS(p)) {
+    if (ERTS_P_LINKS(p) || ERTS_P_MONITORS(p) || ERTS_P_LT_MONITORS(p)) {
 	PrintMonitorContext context = {1, to, to_arg};
 	erts_print(to, to_arg,"Link list: [");
-	erts_doforall_links(ERTS_P_LINKS(p), &doit_print_link, &context);	
-	erts_doforall_monitors(ERTS_P_MONITORS(p), &doit_print_monitor, &context);
+	erts_link_tree_foreach(ERTS_P_LINKS(p), doit_print_link, &context);	
+	erts_monitor_tree_foreach(ERTS_P_MONITORS(p), doit_print_monitor, &context);
+	erts_monitor_list_foreach(ERTS_P_LT_MONITORS(p), doit_print_monitor, &context);
 	erts_print(to, to_arg,"]\n");
     }
 
diff --git a/erts/emulator/beam/dist.c b/erts/emulator/beam/dist.c
index cd799e04b8..fdf307da1b 100644
--- a/erts/emulator/beam/dist.c
+++ b/erts/emulator/beam/dist.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1996-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1996-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -45,6 +45,7 @@
 #include "erl_binary.h"
 #include "erl_thr_progress.h"
 #include "dtrace-wrapper.h"
+#include "erl_proc_sig_queue.h"
 
 #define DIST_CTL_DEFAULT_SIZE 64
 
@@ -109,7 +110,6 @@ int erts_dist_buf_busy_limit;
 
 /* distribution trap functions */
 Export* dmonitor_node_trap = NULL;
-Export* dmonitor_p_trap = NULL;
 
 /* local variables */
 static Export *dist_ctrl_put_data_trap;
@@ -184,6 +184,161 @@ get_suspended_on_de(DistEntry *dep, erts_aint32_t unset_qflgs)
     }
 }
 
+#define ERTS_MON_LNK_FIRE_LIMIT 100
+
+static void monitor_connection_down(ErtsMonitor *mon, void *unused)
+{
+    if (erts_monitor_is_origin(mon))
+        erts_proc_sig_send_demonitor(mon);
+    else
+        erts_proc_sig_send_monitor_down(mon, am_noconnection);
+}
+
+static void link_connection_down(ErtsLink *lnk, void *vdist)
+{
+    erts_proc_sig_send_link_exit(NULL, THE_NON_VALUE, lnk,
+                                 am_noconnection, NIL);
+}
+
+typedef enum {
+    ERTS_CML_CLEANUP_STATE_LINKS,
+    ERTS_CML_CLEANUP_STATE_MONITORS,
+    ERTS_CML_CLEANUP_STATE_ONAME_MONITORS,
+    ERTS_CML_CLEANUP_STATE_NODE_MONITORS
+} ErtsConMonLnkCleaupState;
+
+typedef struct {
+    ErtsConMonLnkCleaupState state;
+    ErtsMonLnkDist *dist;
+    void *yield_state;
+    int trigger_node_monitors;
+    Eterm nodename;
+    Eterm visability;
+    Eterm reason;
+    ErlOffHeap oh;
+    Eterm heap[1];
+} ErtsConMonLnkCleanup;
+
+static void
+con_monitor_link_cleanup(void *vcmlcp)
+{
+    ErtsConMonLnkCleanup *cmlcp = vcmlcp;
+    ErtsMonLnkDist *dist = cmlcp->dist;
+    ErtsSchedulerData *esdp;
+    int yield;
+
+    switch (cmlcp->state) {
+    case ERTS_CML_CLEANUP_STATE_LINKS:
+        yield = erts_link_list_foreach_delete_yielding(&dist->links,
+                                                       link_connection_down,
+                                                       NULL, &cmlcp->yield_state,
+                                                       ERTS_MON_LNK_FIRE_LIMIT);
+        if (yield)
+            break;
+
+        ASSERT(!cmlcp->yield_state);
+        cmlcp->state = ERTS_CML_CLEANUP_STATE_MONITORS;
+    case ERTS_CML_CLEANUP_STATE_MONITORS:
+        yield = erts_monitor_list_foreach_delete_yielding(&dist->monitors,
+                                                          monitor_connection_down,
+                                                          NULL, &cmlcp->yield_state,
+                                                          ERTS_MON_LNK_FIRE_LIMIT);
+        if (yield)
+            break;
+
+        ASSERT(!cmlcp->yield_state);
+        cmlcp->state = ERTS_CML_CLEANUP_STATE_ONAME_MONITORS;
+    case ERTS_CML_CLEANUP_STATE_ONAME_MONITORS:
+        yield = erts_monitor_tree_foreach_delete_yielding(&dist->orig_name_monitors,
+                                                          monitor_connection_down,
+                                                          NULL, &cmlcp->yield_state,
+                                                          ERTS_MON_LNK_FIRE_LIMIT/2);
+        if (yield)
+            break;
+
+        cmlcp->dist = NULL;
+        erts_mon_link_dist_dec_refc(dist);
+
+        ASSERT(!cmlcp->yield_state);
+        cmlcp->state = ERTS_CML_CLEANUP_STATE_NODE_MONITORS;
+    case ERTS_CML_CLEANUP_STATE_NODE_MONITORS:
+        if (cmlcp->trigger_node_monitors) {
+            send_nodes_mon_msgs(NULL,
+                                am_nodedown,
+                                cmlcp->nodename,
+                                cmlcp->visability,
+                                cmlcp->reason);
+        }
+        erts_cleanup_offheap(&cmlcp->oh);
+        erts_free(ERTS_ALC_T_CML_CLEANUP, vcmlcp);
+        return; /* done */
+    }
+
+    /* yield... */
+
+    esdp = erts_get_scheduler_data();
+    ASSERT(esdp && esdp->type == ERTS_SCHED_NORMAL);
+    erts_schedule_misc_aux_work((int) esdp->no,
+                                con_monitor_link_cleanup,
+                                (void *) cmlcp);
+}
+
+static void
+schedule_con_monitor_link_cleanup(ErtsMonLnkDist *dist,
+                                  Eterm nodename,
+                                  Eterm visability,
+                                  Eterm reason)
+{
+    if (dist || is_value(nodename)) {
+        ErtsSchedulerData *esdp;
+        ErtsConMonLnkCleanup *cmlcp;
+        Uint rsz, size;
+
+        size = sizeof(ErtsConMonLnkCleanup);
+
+        if (is_non_value(reason) || is_immed(reason)) {
+            rsz = 0;
+            size -= sizeof(Eterm);
+        }
+        else {
+            rsz = size_object(reason);
+            size += sizeof(Eterm) * (rsz - 1);
+        }
+
+        cmlcp = erts_alloc(ERTS_ALC_T_CML_CLEANUP, size);
+
+        ERTS_INIT_OFF_HEAP(&cmlcp->oh);
+
+        cmlcp->yield_state = NULL;
+        cmlcp->dist = dist;
+        if (!dist)
+            cmlcp->state = ERTS_CML_CLEANUP_STATE_NODE_MONITORS;
+        else {
+            cmlcp->state = ERTS_CML_CLEANUP_STATE_LINKS;
+            erts_mtx_lock(&dist->mtx);
+            ASSERT(dist->alive);
+            dist->alive = 0;
+            erts_mtx_unlock(&dist->mtx);
+        }
+
+        cmlcp->trigger_node_monitors = is_value(nodename);
+        cmlcp->nodename = nodename;
+        cmlcp->visability = visability;
+        if (rsz == 0)
+            cmlcp->reason = reason;
+        else {
+            Eterm *hp = &cmlcp->heap[0];
+            cmlcp->reason = copy_struct(reason, rsz, &hp, &cmlcp->oh);
+        }
+
+        esdp = erts_get_scheduler_data();
+        ASSERT(esdp && esdp->type == ERTS_SCHED_NORMAL);
+        erts_schedule_misc_aux_work((int) esdp->no,
+                                    con_monitor_link_cleanup,
+                                    (void *) cmlcp);
+    }
+}
+
 /*
 ** A full node name constists of a "n@h"
 **
@@ -235,170 +390,6 @@ int is_node_name_atom(Eterm a)
     return is_node_name((char*)atom_tab(i)->name, atom_tab(i)->len);
 }
 
-typedef struct {
-    DistEntry *dep;
-    Eterm *lhp;
-} NetExitsContext;
-
-/* 
-** This function is called when a distribution 
-** port or process terminates
-*/
-static void doit_monitor_net_exits(ErtsMonitor *mon, void *vnecp)
-{
-    Process *rp;
-    ErtsMonitor *rmon;
-    DistEntry *dep = ((NetExitsContext *) vnecp)->dep;
-    ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK;
-
-    rp = erts_pid2proc(NULL, 0, mon->u.pid, rp_locks);
-    if (!rp)
-	goto done;
-
-    if (mon->type == MON_ORIGIN) {
-	/* local pid is being monitored */
-	rmon = erts_remove_monitor(&ERTS_P_MONITORS(rp), mon->ref);
-	/* ASSERT(rmon != NULL); nope, can happen during process exit */
-	if (rmon != NULL) {
-	    erts_destroy_monitor(rmon);
-	}
-    } else {
-	DeclareTmpHeapNoproc(lhp,3);
-	Eterm watched;
-	UseTmpHeapNoproc(3);
-	ASSERT(mon->type == MON_TARGET);
-	rmon = erts_remove_monitor(&ERTS_P_MONITORS(rp), mon->ref);
-	/* ASSERT(rmon != NULL); can happen during process exit */
-	if (rmon != NULL) {
-            ASSERT(rmon->type == MON_ORIGIN);
-	    ASSERT(is_atom(rmon->name) || is_nil(rmon->name));
-	    watched = (is_atom(rmon->name)
-		       ? TUPLE2(lhp, rmon->name, dep->sysname)
-		       : rmon->u.pid);
-	    rp_locks |= ERTS_PROC_LOCKS_MSG_SEND;
-	    erts_proc_lock(rp, ERTS_PROC_LOCKS_MSG_SEND);
-	    erts_queue_monitor_message(rp, &rp_locks, mon->ref, am_process, 
-				       watched, am_noconnection);
-	    erts_destroy_monitor(rmon);
-	}
-	UnUseTmpHeapNoproc(3);
-    }
-    erts_proc_unlock(rp, rp_locks);
- done:
-    erts_destroy_monitor(mon);
-}
-	
-typedef struct {
-    NetExitsContext *necp;
-    ErtsLink *lnk;
-} LinkNetExitsContext;
-
-/* 
-** This is the function actually doing the job of sending exit messages
-** for links in a dist entry upon net_exit (the node goes down), NB,
-** only process links, not node monitors are handled here, 
-** they reside in a separate tree....
-*/
-static void doit_link_net_exits_sub(ErtsLink *sublnk, void *vlnecp)
-{
-    ErtsLink *lnk = ((LinkNetExitsContext *) vlnecp)->lnk; /* the local pid */
-    ErtsLink *rlnk;
-    Process *rp;
-
-    ASSERT(lnk->type == LINK_PID);
-    if (is_internal_pid(lnk->pid)) {
-	int xres;
-	ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCKS_XSIG_SEND;
-
-	rp = erts_pid2proc(NULL, 0, lnk->pid, rp_locks);
-	if (!rp) {
-	    goto done;
-	}
-
-	rlnk = erts_remove_link(&ERTS_P_LINKS(rp), sublnk->pid);
-	xres = erts_send_exit_signal(NULL,
-				     sublnk->pid,
-				     rp,
-				     &rp_locks,
-				     am_noconnection,
-				     NIL,
-				     NULL,
-				     0);
-
-	if (rlnk) {
-	    erts_destroy_link(rlnk);
-	    if (xres >= 0 && IS_TRACED_FL(rp, F_TRACE_PROCS)) {
-		/* We didn't exit the process and it is traced */
-		trace_proc(NULL, 0, rp, am_getting_unlinked, sublnk->pid);
-	    }
-	}
-	erts_proc_unlock(rp, rp_locks);
-    }
- done:
-    erts_destroy_link(sublnk);
-
-}
-    
-
-
-
-
-/* 
-** This function is called when a distribution 
-** port or process terminates, once for each link on the high level, 
-** it in turn traverses the link subtree for the specific link node...
-*/
-static void doit_link_net_exits(ErtsLink *lnk, void *vnecp)
-{
-    LinkNetExitsContext lnec = {(NetExitsContext *) vnecp, lnk};
-    ASSERT(lnk->type == LINK_PID);
-    erts_sweep_links(ERTS_LINK_ROOT(lnk), &doit_link_net_exits_sub, (void *) &lnec);
-#ifdef DEBUG
-    ERTS_LINK_ROOT(lnk) = NULL;
-#endif
-    erts_destroy_link(lnk);
-}
-
-
-static void doit_node_link_net_exits(ErtsLink *lnk, void *vnecp)
-{
-    DistEntry *dep = ((NetExitsContext *) vnecp)->dep;
-    Eterm name = dep->sysname;
-    Process *rp;
-    ErtsLink *rlnk;
-    Uint i,n;
-    ASSERT(lnk->type == LINK_NODE);
-    if (is_internal_pid(lnk->pid)) {
-	ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK;
-	ErlOffHeap *ohp;
-	rp = erts_proc_lookup(lnk->pid);
-	if (!rp)
-	    goto done;
-	erts_proc_lock(rp, rp_locks);
-        if (!ERTS_PROC_IS_EXITING(rp)) {
-            rlnk = erts_remove_link(&ERTS_P_LINKS(rp), name);
-            if (rlnk != NULL) {
-                ASSERT(is_atom(rlnk->pid) && (rlnk->type == LINK_NODE));
-                erts_destroy_link(rlnk);
-            }
-            n = ERTS_LINK_REFC(lnk);
-            for (i = 0; i < n; ++i) {
-                Eterm tup;
-                Eterm *hp;
-                ErtsMessage *msgp;
-
-                msgp = erts_alloc_message_heap(rp, &rp_locks,
-                                               3, &hp, &ohp);
-                tup = TUPLE2(hp, am_nodedown, name);
-                erts_queue_message(rp, rp_locks, msgp, tup, am_system);
-            }
-        }
-	erts_proc_unlock(rp, rp_locks);
-    }
- done:
-    erts_destroy_link(lnk);
-}
-
 static void
 set_node_not_alive(void *unused)
 {
@@ -444,15 +435,8 @@ inc_no_nodes(void)
 static void
 kill_dist_ctrl_proc(void *vpid)
 {
-    Eterm pid = (Eterm) vpid;
-    ErtsProcLocks rp_locks = ERTS_PROC_LOCKS_XSIG_SEND;
-    Process *rp = erts_pid2proc(NULL, 0, pid, rp_locks);
-    if (rp) {
-        erts_send_exit_signal(NULL, rp->common.id, rp, &rp_locks,
-                              am_kill, NIL, NULL, 0);
-        if (rp_locks)
-            erts_proc_unlock(rp, rp_locks);
-    }
+    erts_proc_sig_send_exit(NULL, (Eterm) vpid, (Eterm) vpid,
+                            am_kill, NIL, 0);
 }
 
 static void
@@ -572,10 +556,7 @@ int erts_do_net_exits(DistEntry *dep, Eterm reason)
 	}
     }
     else { /* Call from distribution controller (port/process) */
-	NetExitsContext nec = {dep};
-	ErtsLink *nlinks;
-	ErtsLink *node_links;
-	ErtsMonitor *monitors;
+	ErtsMonLnkDist *mld;
 	Uint32 flags;
 
 	erts_atomic_set_mb(&dep->dist_cmd_scheduled, 1);
@@ -601,14 +582,8 @@ int erts_do_net_exits(DistEntry *dep, Eterm reason)
 	    erts_mtx_unlock(&dep->qlock);
 	}
 
-	erts_de_links_lock(dep);
-	monitors	= dep->monitors;
-        nlinks		= dep->nlinks;
-	node_links	= dep->node_links;
-	dep->monitors	= NULL;
-        dep->nlinks	= NULL;
-	dep->node_links	= NULL;
-	erts_de_links_unlock(dep);
+        mld = dep->mld;
+        dep->mld = NULL;
 
 	nodename = dep->sysname;
 	flags = dep->flags;
@@ -617,15 +592,14 @@ int erts_do_net_exits(DistEntry *dep, Eterm reason)
 
 	erts_de_rwunlock(dep);
 
-	erts_sweep_monitors(monitors, &doit_monitor_net_exits, (void *) &nec);
-	erts_sweep_links(nlinks, &doit_link_net_exits, (void *) &nec);
-	erts_sweep_links(node_links, &doit_node_link_net_exits, (void *) &nec);
-
-	send_nodes_mon_msgs(NULL,
-			    am_nodedown,
-			    nodename,
-			    flags & DFLAG_PUBLISHED ? am_visible : am_hidden,
-			    reason == am_normal ? am_connection_closed : reason);
+        schedule_con_monitor_link_cleanup(mld,
+                                          nodename,
+                                          (flags & DFLAG_PUBLISHED
+                                           ? am_visible
+                                           : am_hidden),
+                                          (reason == am_normal
+                                           ? am_connection_closed
+                                           : reason));
 
 	clear_dist_entry(dep);
     }
@@ -661,7 +635,6 @@ void init_dist(void)
 
     /* Lookup/Install all references to trap functions */
     dmonitor_node_trap = trap_function(am_dmonitor_node,3);
-    dmonitor_p_trap = trap_function(am_dmonitor_p, 2);
     dist_ctrl_put_data_trap = erts_export_put(am_erts_internal,
                                               am_dist_ctrl_put_data,
                                               2);
@@ -771,14 +744,6 @@ static void clear_dist_entry(DistEntry *dep)
     cache = dep->cache;
     dep->cache = NULL;
 
-#ifdef DEBUG
-    erts_de_links_lock(dep);
-    ASSERT(!dep->nlinks);
-    ASSERT(!dep->node_links);
-    ASSERT(!dep->monitors);
-    erts_de_links_unlock(dep);
-#endif
-
     erts_mtx_lock(&dep->qlock);
 
     erts_atomic64_set_nob(&dep->in, 0);
@@ -887,8 +852,7 @@ erts_dsig_send_unlink(ErtsDSigData *dsdp, Eterm local, Eterm remote)
 
 
 /* A local process that's being monitored by a remote one exits. We send:
-   {DOP_MONITOR_P_EXIT, Local pid or name, Remote pid, ref, reason},
-   which is rather sad as only the ref is needed, no pid's... */
+   {DOP_MONITOR_P_EXIT, Local pid or name, Remote pid, ref, reason} */
 int
 erts_dsig_send_m_exit(ErtsDSigData *dsdp, Eterm watcher, Eterm watched, 
 			  Eterm ref, Eterm reason)
@@ -909,12 +873,6 @@ erts_dsig_send_m_exit(ErtsDSigData *dsdp, Eterm watcher, Eterm watched,
     ctl = TUPLE5(&ctl_heap[0], make_small(DOP_MONITOR_P_EXIT),
 		 watched, watcher, ref, reason);
 
-#ifdef DEBUG
-    erts_de_links_lock(dsdp->dep);
-    ASSERT(!erts_lookup_monitor(dsdp->dep->monitors, ref));
-    erts_de_links_unlock(dsdp->dep);
-#endif
-
     res = dsig_send_ctl(dsdp, ctl, 1);
     UnUseTmpHeapNoproc(6);
     return res;
@@ -953,8 +911,7 @@ erts_dsig_send_monitor(ErtsDSigData *dsdp, Eterm watcher, Eterm watched,
 
 /* A local process monitoring a remote one wants to stop monitoring, either 
    because of a demonitor bif call or because the local process died. We send
-   {DOP_DEMONITOR_P, Local pid, Remote pid or name, ref}, which is once again
-   rather redundant as only the ref will be needed on the other side... */
+   {DOP_DEMONITOR_P, Local pid, Remote pid or name, ref} */
 int
 erts_dsig_send_demonitor(ErtsDSigData *dsdp, Eterm watcher,
 			 Eterm watched, Eterm ref, int force)
@@ -1276,8 +1233,6 @@ int erts_net_message(Port *prt,
     Sint type;
     Eterm token;
     Eterm token_size;
-    ErtsMonitor *mon;
-    ErtsLink *lnk;
     Uint tuple_arity;
     int res;
     Uint32 connection_id;
@@ -1375,88 +1330,89 @@ int erts_net_message(Port *prt,
     token = NIL;
 
     switch (type = unsigned_val(tuple[1])) {
-    case DOP_LINK:
+    case DOP_LINK: {
+        ErtsDSigData dsd;
+        int code;
+
 	if (tuple_arity != 3) {
 	    goto invalid_message;
 	}
 	from = tuple[2];
 	to   = tuple[3];  /* local proc to link to */
 
-	if (is_not_pid(from) || is_not_pid(to)) {
-	    goto invalid_message;
-	}
+	if (is_not_external_pid(from))
+            goto invalid_message;
 
-	rp = erts_pid2proc_opt(NULL, 0,
-			       to, ERTS_PROC_LOCK_LINK,
-			       ERTS_P2P_FLG_ALLOW_OTHER_X);
-	if (!rp) {
-	    /* This is tricky (we MUST force a distributed send) */
-	    ErtsDSigData dsd;
-	    int code;
-	    code = erts_dsig_prepare(&dsd, dep, NULL, 0, ERTS_DSP_NO_LOCK, 0, 0);
-	    if (code == ERTS_DSIG_PREP_CONNECTED) {
-		code = erts_dsig_send_exit(&dsd, to, from, am_noproc);
-		ASSERT(code == ERTS_DSIG_SEND_OK);
-	    }
-	    break;
-	}
+        if (dep != external_pid_dist_entry(from))
+            goto invalid_message;
 
-	erts_de_links_lock(dep);
-	res = erts_add_link(&ERTS_P_LINKS(rp), LINK_PID, from);
+        if (is_external_pid(to)) {
+            if (external_pid_dist_entry(to) != erts_this_dist_entry)
+                goto invalid_message;
+            /* old incarnation of node; reply noproc... */
+        }
+        else if (is_internal_pid(to)) {
+            ErtsLinkData *ldp = erts_link_create(ERTS_LNK_TYPE_DIST_PROC,
+                                                 from, to);
+            ASSERT(ldp->a.other.item == to);
+            ASSERT(eq(ldp->b.other.item, from));
+#ifdef DEBUG
+            code =
+#endif
+                erts_link_dist_insert(&ldp->a, dep->mld);
+            ASSERT(code);
 
-	if (res < 0) {
-	    /* It was already there! Lets skip the rest... */
-	    erts_de_links_unlock(dep);
-	    erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-	    break;
-	}
-	lnk = erts_add_or_lookup_link(&(dep->nlinks), LINK_PID, rp->common.id);
-	erts_add_link(&(ERTS_LINK_ROOT(lnk)), LINK_PID, from);
-	erts_de_links_unlock(dep);
+            if (erts_proc_sig_send_link(NULL, to, &ldp->b))
+                break; /* done */
 
-	if (IS_TRACED_FL(rp, F_TRACE_PROCS))
-	    trace_proc(NULL, 0, rp, am_getting_linked, from);
+            /* Failed to send signal; cleanup and reply noproc... */
+
+#ifdef DEBUG
+            code =
+#endif
+                erts_link_dist_delete(&ldp->a);
+            ASSERT(code);
+            erts_link_release_both(ldp);
+        }
+
+        code = erts_dsig_prepare(&dsd, dep, NULL, 0, ERTS_DSP_NO_LOCK, 0, 0);
+        if (code == ERTS_DSIG_PREP_CONNECTED) {
+            code = erts_dsig_send_exit(&dsd, to, from, am_noproc);
+            ASSERT(code == ERTS_DSIG_SEND_OK);
+        }
 
-	erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
 	break;
+    }
 
     case DOP_UNLINK: {
-	ErtsDistLinkData dld;
 	if (tuple_arity != 3) {
 	    goto invalid_message;
 	}
 	from = tuple[2];
 	to = tuple[3];
-	if (is_not_pid(from) || is_not_pid(to)) {
+	if (is_not_external_pid(from))
+	    goto invalid_message;
+        if (dep != external_pid_dist_entry(from))
 	    goto invalid_message;
-	}
-	
-	rp = erts_pid2proc_opt(NULL, 0,
-			       to, ERTS_PROC_LOCK_LINK,
-			       ERTS_P2P_FLG_ALLOW_OTHER_X);
-	if (!rp)
-	    break;
-
-	lnk = erts_remove_link(&ERTS_P_LINKS(rp), from);
 
-	if (IS_TRACED_FL(rp, F_TRACE_PROCS) && lnk != NULL) {
-	    trace_proc(NULL, 0, rp, am_getting_unlinked, from);
-	}
+        if (is_external_pid(to)
+            && erts_this_dist_entry == external_pid_dist_entry(from))
+            break;
 
-	erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
+        if (is_not_internal_pid(to))
+            goto invalid_message;
 
-	erts_remove_dist_link(&dld, to, from, dep);
-	erts_destroy_dist_link(&dld);
-	if (lnk)
-	    erts_destroy_link(lnk);
+        erts_proc_sig_send_dist_unlink(dep, from, to);
 	break;
     }
     
     case DOP_MONITOR_P: {
 	/* A remote process wants to monitor us, we get:
 	   {DOP_MONITOR_P, Remote pid, local pid or name, ref} */
-	Eterm name;
-	
+	Eterm pid, name;
+        ErtsDSigData dsd;
+        int code;
+
 	if (tuple_arity != 4) {
 	    goto invalid_message;
 	}
@@ -1465,44 +1421,64 @@ int erts_net_message(Port *prt,
 	watched = tuple[3];  /* local proc to monitor */
 	ref     = tuple[4];
 
-	if (is_not_ref(ref)) {
+        if (is_not_external_pid(watcher))
+            goto invalid_message;
+        else if (external_pid_dist_entry(watcher) != dep)
+            goto invalid_message;
+
+	if (is_not_ref(ref))
 	    goto invalid_message;
-	}
 
-	if (is_atom(watched)) {
-	    name = watched;
-	    rp = erts_whereis_process(NULL, 0,
-				      watched, ERTS_PROC_LOCK_LINK,
-				      ERTS_P2P_FLG_ALLOW_OTHER_X);
-	}
-	else {
-	    name = NIL;
-	    rp = erts_pid2proc_opt(NULL, 0,
-				   watched, ERTS_PROC_LOCK_LINK,
-				   ERTS_P2P_FLG_ALLOW_OTHER_X);
-	}
+        if (is_internal_pid(watched)) {
+            name = NIL;
+            pid = watched;
+        }
+        else if (is_atom(watched)) {
+            name = watched;
+            pid = erts_whereis_name_to_id(NULL, watched);
+            /* if port or undefined; reply noproc... */
+        }
+        else if (is_external_pid(watched)
+                 && external_pid_dist_entry(watched) == erts_this_dist_entry) {
+            name = NIL;
+            pid = am_undefined; /* old incarnation; reply noproc... */
+        }
+        else
+            goto invalid_message;
 
-	if (!rp) {
-	    ErtsDSigData dsd;
-	    int code;
-	    code = erts_dsig_prepare(&dsd, dep, NULL, 0, ERTS_DSP_NO_LOCK, 0, 0);
-	    if (code == ERTS_DSIG_PREP_CONNECTED) {
-		code = erts_dsig_send_m_exit(&dsd, watcher, watched, ref,
-					     am_noproc);
-		ASSERT(code == ERTS_DSIG_SEND_OK);
-	    }
-	}
-	else {
-	    if (is_atom(watched))
-		watched = rp->common.id;
-	    erts_de_links_lock(dep);
-	    erts_add_monitor(&(dep->monitors), MON_ORIGIN, ref, watched, name);
-	    erts_add_monitor(&ERTS_P_MONITORS(rp), MON_TARGET, ref, watcher, name);
-	    erts_de_links_unlock(dep);
-	    erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-	}
+        if (is_internal_pid(pid)) {
+            ErtsMonitorData *mdp;
+            mdp = erts_monitor_create(ERTS_MON_TYPE_DIST_PROC,
+                                      ref, watcher, pid, name);
 
-	break;
+#ifdef DEBUG
+            code =
+#endif
+                erts_monitor_dist_insert(&mdp->origin, dep->mld);
+            ASSERT(code);
+
+            if (erts_proc_sig_send_monitor(&mdp->target, pid))
+                break; /* done */
+
+            /* Failed to send to local proc; cleanup reply noproc... */
+
+#ifdef DEBUG
+            code =
+#endif
+                erts_monitor_dist_delete(&mdp->origin);
+            ASSERT(code);
+            erts_monitor_release_both(mdp);
+
+        }
+
+        code = erts_dsig_prepare(&dsd, dep, NULL, 0, ERTS_DSP_NO_LOCK, 0, 0);
+        if (code == ERTS_DSIG_PREP_CONNECTED) {
+            code = erts_dsig_send_m_exit(&dsd, watcher, watched, ref,
+                                         am_noproc);
+            ASSERT(code == ERTS_DSIG_SEND_OK);
+        }
+
+        break;
     }
 
     case DOP_DEMONITOR_P:
@@ -1513,36 +1489,43 @@ int erts_net_message(Port *prt,
 	if (tuple_arity != 4) {
 	    goto invalid_message;
 	}
-	/* watcher = tuple[2]; */
-	/* watched = tuple[3]; May be an atom in case of monitor name */
+
+	watcher = tuple[2];
+	watched = tuple[3];
 	ref = tuple[4];
 
-	if(is_not_ref(ref)) {
+	if (is_not_ref(ref)) {
 	    goto invalid_message;
 	}
 
-	erts_de_links_lock(dep);
-	mon = erts_remove_monitor(&(dep->monitors),ref);
-	erts_de_links_unlock(dep);
-	/* ASSERT(mon != NULL); can happen in case of broken dist message */
-	if (mon == NULL) {
-	    break;
-	}
-	watched = mon->u.pid;
-	erts_destroy_monitor(mon);
-	rp = erts_pid2proc_opt(NULL, 0,
-			       watched, ERTS_PROC_LOCK_LINK,
-			       ERTS_P2P_FLG_ALLOW_OTHER_X);
-	if (!rp) {
-	    break;
-	}
-	mon = erts_remove_monitor(&ERTS_P_MONITORS(rp), ref);
-	erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-	ASSERT(mon != NULL);
-	if (mon == NULL) {
-	    break;
-	}
-	erts_destroy_monitor(mon);
+        if (is_not_external_pid(watcher) || external_pid_dist_entry(watcher) != dep)
+            goto invalid_message;
+
+        if (is_internal_pid(watched))
+            erts_proc_sig_send_dist_demonitor(watched, ref);
+        else if (is_external_pid(watched)
+                 && external_pid_dist_entry(watched) == erts_this_dist_entry) {
+            /* old incarnation; ignore it */
+            ;
+        }
+        else if (is_atom(watched)) {
+            ErtsMonLnkDist *mld = dep->mld;
+            ErtsMonitor *mon;
+
+            erts_mtx_lock(&mld->mtx);
+
+            mon = erts_monitor_tree_lookup(mld->orig_name_monitors, ref);
+            if (mon)
+                erts_monitor_tree_delete(&mld->orig_name_monitors, mon);
+
+            erts_mtx_unlock(&mld->mtx);
+
+            if (mon)
+                erts_proc_sig_send_demonitor(mon);
+        }
+        else
+            goto invalid_message;
+
 	break;
 
     case DOP_REG_SEND_TT:
@@ -1669,68 +1652,36 @@ int erts_net_message(Port *prt,
 	/* We are monitoring a process on the remote node which dies, we get
 	   {DOP_MONITOR_P_EXIT, Remote pid or name, Local pid, ref, reason} */
 	   
-
-	DeclareTmpHeapNoproc(lhp,3);
-	Eterm sysname;
-	ErtsProcLocks rp_locks = ERTS_PROC_LOCKS_MSG_SEND|ERTS_PROC_LOCK_LINK;
-
 	if (tuple_arity != 5) {
 	    goto invalid_message;
 	}
 
-	/* watched = tuple[2]; */  /* remote proc which died */
-	/* watcher = tuple[3]; */
+	watched = tuple[2];  /* remote proc or name which died */
+	watcher = tuple[3];
 	ref     = tuple[4];
 	reason  = tuple[5];
 
-	if(is_not_ref(ref)) {
+	if (is_not_ref(ref))
 	    goto invalid_message;
-	}
-
-	erts_de_links_lock(dep);
-	sysname = dep->sysname;
-	mon = erts_remove_monitor(&(dep->monitors), ref);
-	/*
-	 * If demonitor was performed at the same time as the
-	 * monitored process exits, monitoring side will have
-	 * removed info about monitor. In this case, do nothing
-	 * and everything will be as it should.
-	 */
-	erts_de_links_unlock(dep);
-	if (mon == NULL) {
-	    break;
-	}
-	rp = erts_pid2proc(NULL, 0, mon->u.pid, rp_locks);
 
-	erts_destroy_monitor(mon);
-	if (rp == NULL) {
-	    break;
-	}
+        if (is_not_external_pid(watched) && is_not_atom(watched))
+            goto invalid_message;
 
-	mon = erts_remove_monitor(&ERTS_P_MONITORS(rp), ref);
+        if (is_not_internal_pid(watcher)) {
+            if (!is_external_pid(watcher))
+                goto invalid_message;
+            if (erts_this_dist_entry == external_pid_dist_entry(watcher))
+                break;
+            goto invalid_message;
+        }
 
-	if (mon == NULL) {
-	    erts_proc_unlock(rp, rp_locks);
-	    break;
-	}
-	UseTmpHeapNoproc(3);
-	
-	watched = (is_not_nil(mon->name)
-		   ? TUPLE2(&lhp[0], mon->name, sysname)
-		   : mon->u.pid);
-	
-	erts_queue_monitor_message(rp, &rp_locks,
-				   ref, am_process, watched, reason);
-	erts_proc_unlock(rp, rp_locks);
-	erts_destroy_monitor(mon);
-	UnUseTmpHeapNoproc(3);
+        erts_proc_sig_send_dist_monitor_down(dep, ref, watched,
+                                             watcher, reason);
 	break;
     }
 
     case DOP_EXIT_TT:
     case DOP_EXIT: {
-	ErtsDistLinkData dld;
-	ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCKS_XSIG_SEND;
 	/* 'from', which 'to' is linked to, died */
 	if (type == DOP_EXIT) {
 	    if (tuple_arity != 4) {
@@ -1750,56 +1701,19 @@ int erts_net_message(Port *prt,
 	    token = tuple[4];
 	    reason = tuple[5];
 	}
-	if (is_not_pid(from) || is_not_internal_pid(to)) {
+	if (is_not_external_pid(from)
+            || dep != external_pid_dist_entry(from)
+            || is_not_internal_pid(to)) {
 	    goto invalid_message;
 	}
 
-	rp = erts_pid2proc(NULL, 0, to, rp_locks);
-	if (!rp)
-	    lnk = NULL;
-	else {
-	    lnk = erts_remove_link(&ERTS_P_LINKS(rp), from);
-
-	    /* If lnk == NULL, we have unlinked on this side, i.e.
-	     * ignore exit.
-	     */
-	    if (lnk) {
-		int xres;
-#if 0
-		/* Arndt: Maybe it should never be 'kill', but it can be,
-		   namely when a linked process does exit(kill). Until we know
-		   whether that is incorrect and what should happen instead,
-		   we leave the assertion out. */
-		ASSERT(reason != am_kill); /* should never be kill (killed) */
-#endif
-		xres = erts_send_exit_signal(NULL,
-					     from,
-					     rp,
-					     &rp_locks, 
-					     reason,
-					     token,
-					     NULL,
-					     ERTS_XSIG_FLG_IGN_KILL);
-		if (xres >= 0 && IS_TRACED_FL(rp, F_TRACE_PROCS)) {
-		    /* We didn't exit the process and it is traced */
-                    if (rp_locks & ERTS_PROC_LOCKS_XSIG_SEND) {
-                        erts_proc_unlock(rp, ERTS_PROC_LOCKS_XSIG_SEND);
-                        rp_locks &= ~ERTS_PROC_LOCKS_XSIG_SEND;
-                    }
-		    trace_proc(NULL, 0, rp, am_getting_unlinked, from);
-		}
-	    }
-	    erts_proc_unlock(rp, rp_locks);
-	}
-	erts_remove_dist_link(&dld, to, from, dep);
-	if (lnk)
-	    erts_destroy_link(lnk);
-	erts_destroy_dist_link(&dld);
+        erts_proc_sig_send_dist_link_exit(dep,
+                                          from, to,
+                                          reason, token);
 	break;
     }
     case DOP_EXIT2_TT:
-    case DOP_EXIT2: {
-	ErtsProcLocks rp_locks = ERTS_PROC_LOCKS_XSIG_SEND;
+    case DOP_EXIT2:
 	/* 'from' is send an exit signal to 'to' */
 	if (type == DOP_EXIT2) {
 	    if (tuple_arity != 4) {
@@ -1821,20 +1735,10 @@ int erts_net_message(Port *prt,
 	if (is_not_pid(from) || is_not_internal_pid(to)) {
 	    goto invalid_message;
 	}
-	rp = erts_pid2proc(NULL, 0, to, rp_locks);
-	if (rp) {
-	    (void) erts_send_exit_signal(NULL,
-					 from,
-					 rp,
-					 &rp_locks,
-					 reason,
-					 token,
-					 NULL,
-					 0);
-	    erts_proc_unlock(rp, rp_locks);
-	}
+
+        erts_proc_sig_send_exit(NULL, from, to, reason, token, 0);
 	break;
-    }
+
     case DOP_GROUP_LEADER:
 	if (tuple_arity != 3) {
 	    goto invalid_message;
@@ -1845,11 +1749,7 @@ int erts_net_message(Port *prt,
 	    goto invalid_message;
 	}
 
-	rp = erts_pid2proc(NULL, 0, to, ERTS_PROC_LOCK_MAIN);
-	if (!rp)
-	    break;
-	rp->group_leader = STORE_NC_IN_PROC(rp, from);
-	erts_proc_unlock(rp, ERTS_PROC_LOCK_MAIN);
+        (void) erts_proc_sig_send_group_leader(NULL, to, from, NIL);
 	break;
 
     default: 
@@ -2989,57 +2889,55 @@ static void doit_print_monitor_info(ErtsMonitor *mon, void *vptdp)
 {
     fmtfn_t to = ((struct print_to_data *) vptdp)->to;
     void *arg = ((struct print_to_data *) vptdp)->arg;
-    Process *rp;
-    ErtsMonitor *rmon;
-    rp = erts_proc_lookup(mon->u.pid);
-    if (!rp || (rmon = erts_lookup_monitor(ERTS_P_MONITORS(rp), mon->ref)) == NULL) {
-	erts_print(to, arg, "Warning, stray monitor for: %T\n", mon->u.pid);
-    } else if (mon->type == MON_ORIGIN) {
-	/* Local pid is being monitored */
+    ErtsMonitorDataExtended *mdep;
+
+    ASSERT(mon->flags & ERTS_ML_FLG_EXTENDED);
+
+    mdep = (ErtsMonitorDataExtended *) erts_monitor_to_data(mon);
+
+    ASSERT(mdep->dist);
+
+    if (erts_monitor_is_origin(mon)) {
 	erts_print(to, arg, "Remotely monitored by: %T %T\n",
-		   mon->u.pid, rmon->u.pid);
-    } else {
-	erts_print(to, arg, "Remote monitoring: %T ", mon->u.pid);
-	if (is_not_atom(rmon->u.pid))
-	    erts_print(to, arg, "%T\n", rmon->u.pid);
-	else
-	    erts_print(to, arg, "{%T, %T}\n",
-		       rmon->name,
-		       rmon->u.pid); /* which in this case is the 
-				      remote system name... */
+		   mon->other.item, mdep->md.target.other.item);
+    }
+    else {
+	erts_print(to, arg, "Remote monitoring: %T ", mon->other.item);
+        if (mon->flags & ERTS_ML_FLG_NAME)
+	    erts_print(to, arg, "{%T, %T}\n", mdep->u.name, mdep->dist->nodename);
+        else
+	    erts_print(to, arg, "%T\n", mdep->md.origin.other.item);
     }
 }    
 
-static void print_monitor_info(fmtfn_t to, void *arg, ErtsMonitor *mon)
+static void print_monitor_info(fmtfn_t to, void *arg, DistEntry *dep)
 {
     struct print_to_data ptd = {to, arg};
-    erts_doforall_monitors(mon,&doit_print_monitor_info,&ptd);
-}
-
-typedef struct {
-    struct print_to_data *ptdp;
-    Eterm from;
-} PrintLinkContext;
-
-static void doit_print_link_info2(ErtsLink *lnk, void *vpplc)
-{
-    PrintLinkContext *pplc = (PrintLinkContext *) vpplc;
-    erts_print(pplc->ptdp->to, pplc->ptdp->arg, "Remote link: %T %T\n",
-	       pplc->from, lnk->pid);
+    if (dep->mld) {
+        erts_monitor_list_foreach(dep->mld->monitors,
+                                  doit_print_monitor_info,
+                                  (void *) &ptd);
+        erts_monitor_tree_foreach(dep->mld->orig_name_monitors,
+                                  doit_print_monitor_info,
+                                  (void *) &ptd);
+    }
 }
 
 static void doit_print_link_info(ErtsLink *lnk, void *vptdp)
 {
-    if (is_internal_pid(lnk->pid) && erts_proc_lookup(lnk->pid)) {
-	PrintLinkContext plc = {(struct print_to_data *) vptdp, lnk->pid};
-	erts_doforall_links(ERTS_LINK_ROOT(lnk), &doit_print_link_info2, &plc);
-    } 
+    struct print_to_data *ptdp = vptdp;
+    ErtsLink *lnk2 = erts_link_to_other(lnk, NULL);
+    erts_print(ptdp->to, ptdp->arg, "Remote link: %T %T\n",
+	       lnk2->other.item, lnk->other.item);
 }
 
-static void print_link_info(fmtfn_t to, void *arg, ErtsLink *lnk)
+static void print_link_info(fmtfn_t to, void *arg, DistEntry *dep)
 {
     struct print_to_data ptd = {to, arg};
-    erts_doforall_links(lnk, &doit_print_link_info, (void *) &ptd);
+    if (dep->mld)
+        erts_link_list_foreach(dep->mld->links,
+                               doit_print_link_info,
+                               (void *) &ptd);
 }
 
 typedef struct {
@@ -3047,23 +2945,6 @@ typedef struct {
     Eterm sysname;
 } PrintNodeLinkContext;
     
-
-static void doit_print_nodelink_info(ErtsLink *lnk, void *vpcontext)
-{
-    PrintNodeLinkContext *pcontext = vpcontext;
-
-    if (is_internal_pid(lnk->pid) && erts_proc_lookup(lnk->pid))
-	erts_print(pcontext->ptd.to, pcontext->ptd.arg,
-		   "Remote monitoring: %T %T\n", lnk->pid, pcontext->sysname);
-}
-
-static void print_nodelink_info(fmtfn_t to, void *arg, ErtsLink *lnk, Eterm sysname)
-{
-    PrintNodeLinkContext context = {{to, arg}, sysname};
-    erts_doforall_links(lnk, &doit_print_nodelink_info, &context);
-}
-
-
 static int
 info_dist_entry(fmtfn_t to, void *arg, DistEntry *dep, int visible, int connected)
 {
@@ -3094,8 +2975,8 @@ info_dist_entry(fmtfn_t to, void *arg, DistEntry *dep, int visible, int connecte
   erts_print(to, arg, "Name: %T", dep->sysname);
   erts_print(to, arg, "\n");
   if (!connected && is_nil(dep->cid)) {
-    if (dep->nlinks) {
-      erts_print(to, arg, "Error: Got links to not connected node:%T\n",
+    if (dep->mld) {
+      erts_print(to, arg, "Error: Got links/monitors to not connected node:%T\n",
 		 dep->sysname);
     }
     return 0;
@@ -3104,9 +2985,8 @@ info_dist_entry(fmtfn_t to, void *arg, DistEntry *dep, int visible, int connecte
   erts_print(to, arg, "Controller: %T\n", dep->cid, to);
 
   erts_print_node_info(to, arg, dep->sysname, NULL, NULL);
-  print_monitor_info(to, arg, dep->monitors);
-  print_link_info(to, arg, dep->nlinks);
-  print_nodelink_info(to, arg, dep->node_links, dep->sysname);
+  print_monitor_info(to, arg, dep);
+  print_link_info(to, arg, dep);
 
   return 0;
     
@@ -3193,8 +3073,7 @@ BIF_RETTYPE setnode_2(BIF_ALIST_2)
 	goto error;
 
     /* Check that all trap functions are defined !! */
-    if (dmonitor_node_trap->addressv[0] == NULL ||
-	dmonitor_p_trap->addressv[0] == NULL) {
+    if (dmonitor_node_trap->addressv[0] == NULL) {
 	goto error;
     }
 
@@ -3582,25 +3461,16 @@ static Sint abort_connection(DistEntry* dep, Uint32 conn_id)
         kill_connection(dep);
     }
     else if (dep->state == ERTS_DE_STATE_PENDING) {
-        NetExitsContext nec = {dep};
-        ErtsLink *nlinks;
-        ErtsLink *node_links;
-        ErtsMonitor *monitors;
         ErtsAtomCache *cache;
         ErtsDistOutputBuf *obuf;
         ErtsProcList *resume_procs;
         Sint reds = 0;
+        ErtsMonLnkDist *mld;
 
 	ASSERT(is_nil(dep->cid));
 
-	erts_de_links_lock(dep);
-	monitors	= dep->monitors;
-	nlinks		= dep->nlinks;
-	node_links	= dep->node_links;
-	dep->monitors	= NULL;
-	dep->nlinks	= NULL;
-	dep->node_links	= NULL;
-	erts_de_links_unlock(dep);
+        mld = dep->mld;
+        dep->mld = NULL;
 
 	cache = dep->cache;
 	dep->cache = NULL;
@@ -3619,9 +3489,8 @@ static Sint abort_connection(DistEntry* dep, Uint32 conn_id)
 
 	erts_de_rwunlock(dep);
 
-	erts_sweep_monitors(monitors, &doit_monitor_net_exits, &nec);
-	erts_sweep_links(nlinks, &doit_link_net_exits, &nec);
-	erts_sweep_links(node_links, &doit_node_link_net_exits, &nec);
+        schedule_con_monitor_link_cleanup(mld, THE_NON_VALUE,
+                                          THE_NON_VALUE, THE_NON_VALUE);
 
         if (resume_procs) {
             int resumed = erts_resume_processes(resume_procs);
@@ -3861,8 +3730,8 @@ BIF_RETTYPE is_alive_0(BIF_ALIST_0)
 static BIF_RETTYPE
 monitor_node(Process* p, Eterm Node, Eterm Bool, Eterm Options)
 {
-    DistEntry *dep;
-    ErtsLink *lnk;
+    BIF_RETTYPE ret;
+    DistEntry *dep = NULL;
     Eterm l;
     int async_connect = 1;
 
@@ -3881,33 +3750,71 @@ monitor_node(Process* p, Eterm Node, Eterm Bool, Eterm Options)
     if (l != NIL) {
 	BIF_ERROR(p, BADARG);
     }
+    if (l != NIL)
+        goto badarg;
 
-    if (is_not_atom(Node) ||
-	((Bool != am_true) && (Bool != am_false)) ||
-	((erts_this_node->sysname == am_Noname)
-	 && (Node != erts_this_node->sysname))) {
-	BIF_ERROR(p, BADARG);
+    if (is_not_atom(Node))
+        goto badarg;
+
+    if (erts_this_node->sysname == am_Noname && Node != am_Noname)
+	goto badarg;
+
+    switch (Bool) {
+
+    case am_false: {
+        ErtsMonitor *mon;
+        /*
+         * Before OTP-21, monitor_node(Node, false) triggered
+         * auto-connect and a 'nodedown' message if that failed.
+         * Now it's a simple no-op which feels more reasonable.
+         */
+        mon = erts_monitor_tree_lookup(ERTS_P_MONITORS(p), Node);
+        if (mon) {
+            ErtsMonitorDataExtended *mdep;
+            ASSERT(erts_monitor_is_origin(mon));
+
+            mdep = (ErtsMonitorDataExtended *) erts_monitor_to_data(mon);
+
+            ASSERT((mdep->u.refc > 0));
+            if (--mdep->u.refc == 0) {
+                if (!mdep->uptr.node_monitors)
+                    erts_monitor_tree_delete(&ERTS_P_MONITORS(p), mon);
+                else {
+                    ErtsMonitor *sub_mon;
+                    ErtsMonitorDataExtended *sub_mdep;
+                    sub_mon = erts_monitor_list_last(mdep->uptr.node_monitors);
+                    erts_monitor_list_delete(&mdep->uptr.node_monitors, sub_mon);
+                    sub_mon->flags &= ~ERTS_ML_FLG_IN_SUBTABLE;
+                    sub_mdep = ((ErtsMonitorDataExtended *)
+                                erts_monitor_to_data(sub_mon));
+                    sub_mdep->uptr.node_monitors = mdep->uptr.node_monitors;
+                    mdep->uptr.node_monitors = NULL;
+                    erts_monitor_tree_replace(&ERTS_P_MONITORS(p), mon, sub_mon);
+                }
+                if (erts_monitor_dist_delete(&mdep->md.target))
+                    erts_monitor_release_both((ErtsMonitorData *) mdep);
+                else
+                    erts_monitor_release(mon);
+            }
+        }
+        break;
     }
 
-    if (Bool == am_true) {
+    case am_true: {
         ErtsDSigData dsd;
         dsd.node = Node;
+
         dep = erts_find_or_insert_dist_entry(Node);
         if (dep == erts_this_dist_entry)
-            goto done;
-
-        erts_proc_lock(p, ERTS_PROC_LOCK_LINK);
+            break;
 
         switch (erts_dsig_prepare(&dsd, dep, p,
-                                  (ERTS_PROC_LOCK_MAIN | ERTS_PROC_LOCK_LINK),
+                                  ERTS_PROC_LOCK_MAIN,
                                   ERTS_DSP_RLOCK, 0, async_connect)) {
         case ERTS_DSIG_PREP_NOT_ALIVE:
 	case ERTS_DSIG_PREP_NOT_CONNECTED:
 	    /* Trap to either send 'nodedown' or do passive connection attempt */
-	trap:
-            erts_proc_unlock(p, ERTS_PROC_LOCK_LINK);
-	    erts_deref_dist_entry(dep);
-            BIF_TRAP3(dmonitor_node_trap, p, Node, Bool, Options);
+            goto do_trap;
 	case ERTS_DSIG_PREP_PENDING:
 	    if (!async_connect) {
 		/*
@@ -3915,68 +3822,87 @@ monitor_node(Process* p, Eterm Node, Eterm Bool, Eterm Options)
 		 * to ensure passive connection attempt
 		 */
 		erts_de_runlock(dep);
-		goto trap;
+		goto do_trap;
 	    }
 	    /*fall through*/
-        case ERTS_DSIG_PREP_CONNECTED:
-            erts_de_links_lock(dep);
-            erts_de_runlock(dep);
-            lnk = erts_add_or_lookup_link(&(dep->node_links), LINK_NODE,
-                                          p->common.id);
-            ++ERTS_LINK_REFC(lnk);
-            lnk = erts_add_or_lookup_link(&ERTS_P_LINKS(p), LINK_NODE, Node);
-            ++ERTS_LINK_REFC(lnk);
-            erts_de_links_unlock(dep);
+        case ERTS_DSIG_PREP_CONNECTED: {
+            ErtsMonitor *mon;
+            ErtsMonitorDataExtended *mdep;
+            int created;
+
+            mon = erts_monitor_tree_lookup_create(&ERTS_P_MONITORS(p),
+                                                  &created,
+                                                  ERTS_MON_TYPE_NODE,
+                                                  p->common.id,
+                                                  Node);
+            mdep = (ErtsMonitorDataExtended *) erts_monitor_to_data(mon);
+            if (created) {
+#ifdef DEBUG
+                int inserted =
+#endif
+                    erts_monitor_dist_insert(&mdep->md.target, dep->mld);
+                ASSERT(inserted);
+                ASSERT(mdep->dist->connection_id == dep->connection_id);
+            }
+            else if (mdep->dist->connection_id != dep->connection_id) {
+                ErtsMonitorDataExtended *mdep2;
+                ErtsMonitor *mon2;
+#ifdef DEBUG
+                int inserted;
+#endif
+                mdep2 = ((ErtsMonitorDataExtended *)
+                         erts_monitor_create(ERTS_MON_TYPE_NODE, NIL,
+                                             p->common.id, Node, NIL));
+                mon2 = &mdep2->md.origin;
+#ifdef DEBUG
+                inserted =
+#endif
+                    erts_monitor_dist_insert(&mdep->md.target, dep->mld);
+                ASSERT(inserted);
+                ASSERT(mdep2->dist->connection_id == dep->connection_id);
+
+                mdep2->uptr.node_monitors = mdep->uptr.node_monitors;
+                mdep->uptr.node_monitors = NULL;
+                erts_monitor_tree_replace(&ERTS_P_MONITORS(p), mon, mon2);
+                erts_monitor_list_insert(&mdep2->uptr.node_monitors, mon);
+                mon->flags |= ERTS_ML_FLG_IN_SUBTABLE;
+                mdep = mdep2;
+            }
+
+            mdep->u.refc++;
+
             break;
+        }
+
         default:
             ERTS_ASSERT(! "Invalid dsig prepare result");
         }
-        erts_deref_dist_entry(dep);
-    }
-    else { /* Bool == false */
-        dep = erts_sysname_to_connected_dist_entry(Node);
-        if (!dep) {
-	    /*
-	     * Before OTP-21 this case triggered auto-connect
-	     * and a 'nodedown' message if that failed.
-	     * Now it's a simple no-op which feels more reasonable.
-	     */
-            BIF_RET(am_true);
-        }
-        if (dep == erts_this_dist_entry)
-            goto done;
 
-        erts_proc_lock(p, ERTS_PROC_LOCK_LINK);
-        erts_de_rlock(dep);
-        if (dep->state == ERTS_DE_STATE_IDLE) {
-            ASSERT(!dep->node_links);
-            erts_proc_unlock(p, ERTS_PROC_LOCK_LINK);
-            erts_de_runlock(dep);
-            goto done;
-        }
-        erts_de_links_lock(dep);
         erts_de_runlock(dep);
-        lnk = erts_lookup_link(dep->node_links, p->common.id);
-        if (lnk != NULL) {
-            if ((--ERTS_LINK_REFC(lnk)) == 0) {
-                erts_destroy_link(erts_remove_link(&(dep->node_links),
-                                                   p->common.id));
-            }
-        }
-        lnk = erts_lookup_link(ERTS_P_LINKS(p), Node);
-        if (lnk != NULL) {
-            if ((--ERTS_LINK_REFC(lnk)) == 0) {
-                erts_destroy_link(erts_remove_link(&ERTS_P_LINKS(p),
-                                                   Node));
-            }
-        }
-        erts_de_links_unlock(dep);
+
+        break;
     }
 
-    erts_proc_unlock(p, ERTS_PROC_LOCK_LINK);
+    default:
+        goto badarg;
+    }
 
- done:
-    BIF_RET(am_true);
+    ERTS_BIF_PREP_RET(ret, am_true);
+
+do_return:
+
+    if (dep)
+        erts_deref_dist_entry(dep);
+
+    return ret;
+
+do_trap:
+    ERTS_BIF_PREP_TRAP3(ret, dmonitor_node_trap, p, Node, Bool, Options);
+    goto do_return;
+
+badarg:
+    ERTS_BIF_PREP_ERROR(ret, p, BADARG);
+    goto do_return;
 }
 
 BIF_RETTYPE monitor_node_3(BIF_ALIST_3)
@@ -4027,18 +3953,9 @@ BIF_RETTYPE net_kernel_dflag_unicode_io_1(BIF_ALIST_1)
 #define ERTS_NODES_MON_OPT_TYPES \
   (ERTS_NODES_MON_OPT_TYPE_VISIBLE|ERTS_NODES_MON_OPT_TYPE_HIDDEN)
 
-typedef struct ErtsNodesMonitor_ ErtsNodesMonitor;
-struct ErtsNodesMonitor_ {
-    ErtsNodesMonitor *prev;
-    ErtsNodesMonitor *next;
-    Process *proc;
-    Uint16 opts;
-    Uint16 no;
-};
-
 static erts_mtx_t nodes_monitors_mtx;
-static ErtsNodesMonitor *nodes_monitors;
-static ErtsNodesMonitor *nodes_monitors_end;
+static ErtsMonitor *nodes_monitors;
+static Uint no_nodes_monitors;
 
 /*
  * Nodes monitors are stored in a double linked list. 'nodes_monitors'
@@ -4057,109 +3974,169 @@ init_nodes_monitors(void)
     erts_mtx_init(&nodes_monitors_mtx, "nodes_monitors", NIL,
         ERTS_LOCK_FLAGS_PROPERTY_STATIC | ERTS_LOCK_FLAGS_CATEGORY_DISTRIBUTION);
     nodes_monitors = NULL;
-    nodes_monitors_end = NULL;
+    no_nodes_monitors = 0;
 }
 
-static ERTS_INLINE Uint
-nodes_mon_msg_sz(ErtsNodesMonitor *nmp, Eterm what, Eterm reason)
+Eterm
+erts_monitor_nodes(Process *c_p, Eterm on, Eterm olist)
 {
-    Uint sz;
-    if (!nmp->opts) {
-	sz = 3;
-    }
-    else {
-	sz = 0;
+    Eterm key, old_value, opts_list = olist;
+    Uint opts = (Uint) 0;
 
-	if (nmp->opts & ERTS_NODES_MON_OPT_TYPES)
-	    sz += 2 + 3;
+    ASSERT(c_p);
+    ERTS_LC_ASSERT(erts_proc_lc_my_proc_locks(c_p) == ERTS_PROC_LOCK_MAIN);
 
-	if (what == am_nodedown
-	    && (nmp->opts & ERTS_NODES_MON_OPT_DOWN_REASON)) {
-	    if (is_not_immed(reason))
-		sz += size_object(reason);
-	    sz += 2 + 3;
+    if (on != am_true && on != am_false)
+	return THE_NON_VALUE;
+
+    if (is_not_nil(opts_list)) {
+	int all = 0, visible = 0, hidden = 0;
+
+	while (is_list(opts_list)) {
+	    Eterm *cp = list_val(opts_list);
+	    Eterm opt = CAR(cp);
+	    opts_list = CDR(cp);
+	    if (opt == am_nodedown_reason)
+		opts |= ERTS_NODES_MON_OPT_DOWN_REASON;
+	    else if (is_tuple(opt)) {
+		Eterm* tp = tuple_val(opt);
+		if (arityval(tp[0]) != 2)
+		    return THE_NON_VALUE;
+		switch (tp[1]) {
+		case am_node_type:
+		    switch (tp[2]) {
+		    case am_visible:
+			if (hidden || all)
+			    return THE_NON_VALUE;
+			opts |= ERTS_NODES_MON_OPT_TYPE_VISIBLE;
+			visible = 1;
+			break;
+		    case am_hidden:
+			if (visible || all)
+			    return THE_NON_VALUE;
+			opts |= ERTS_NODES_MON_OPT_TYPE_HIDDEN;
+			hidden = 1;
+			break;
+		    case am_all:
+			if (visible || hidden)
+			    return THE_NON_VALUE;
+			opts |= ERTS_NODES_MON_OPT_TYPES;
+			all = 1;
+			break;
+		    default:
+			return THE_NON_VALUE;
+		    }
+		    break;
+		default:
+		    return THE_NON_VALUE;
+		}
+	    }
+	    else {
+		return THE_NON_VALUE;
+	    }
 	}
 
-	sz += 4;
+	if (is_not_nil(opts_list))
+	    return THE_NON_VALUE;
     }
-    return sz;
+
+    key = make_small(opts);
+
+    if (on == am_true) {
+        ErtsMonitorDataExtended *mdep;
+        ErtsMonitor *omon;
+        int created;
+        omon = erts_monitor_tree_lookup_create(&ERTS_P_MONITORS(c_p),
+                                               &created,
+                                               ERTS_MON_TYPE_NODES,
+                                               c_p->common.id,
+                                               key);
+        mdep = (ErtsMonitorDataExtended *) erts_monitor_to_data(omon);
+        if (created) {
+            erts_mtx_lock(&nodes_monitors_mtx);
+            no_nodes_monitors++;
+            erts_monitor_list_insert(&nodes_monitors, &mdep->md.target);
+            erts_mtx_unlock(&nodes_monitors_mtx);
+        }
+        old_value = mdep->u.refc;
+        mdep->u.refc++;
+    }
+    else {
+        ErtsMonitorDataExtended *mdep;
+        ErtsMonitor *omon;
+        omon = erts_monitor_tree_lookup(ERTS_P_MONITORS(c_p), key);
+        if (!omon)
+            old_value = 0;
+        else {
+            mdep = (ErtsMonitorDataExtended *) erts_monitor_to_data(omon);
+            old_value = mdep->u.refc;
+            ASSERT(mdep->u.refc > 0);
+            erts_mtx_lock(&nodes_monitors_mtx);
+            ASSERT(no_nodes_monitors > 0);
+            no_nodes_monitors--;
+            ASSERT(erts_monitor_is_in_table(&mdep->md.target));
+            erts_monitor_list_delete(&nodes_monitors, &mdep->md.target);
+            erts_mtx_unlock(&nodes_monitors_mtx);
+            erts_monitor_tree_delete(&ERTS_P_MONITORS(c_p), omon);
+            erts_monitor_release_both((ErtsMonitorData *) mdep);
+        }
+    }
+
+    return erts_make_integer(old_value, c_p);
 }
 
-static ERTS_INLINE void
-send_nodes_mon_msg(Process *rp,
-		   ErtsProcLocks *rp_locksp,
-		   ErtsNodesMonitor *nmp,
-		   Eterm node,
-		   Eterm what,
-		   Eterm type,
-		   Eterm reason,
-		   Uint sz)
+void
+erts_monitor_nodes_delete(ErtsMonitor *omon)
 {
-    Eterm msg;
-    Eterm *hp;
-    ErtsMessage *mp;
-    ErlOffHeap *ohp;
-#ifdef DEBUG
-    Eterm *hend;
-#endif
+    ErtsMonitorData *mdp;
 
-    mp = erts_alloc_message_heap(rp, rp_locksp, sz, &hp, &ohp);
-#ifdef DEBUG
-    hend = hp + sz;
-#endif
+    ASSERT(omon->type == ERTS_MON_TYPE_NODES);
+    ASSERT(erts_monitor_is_origin(omon));
 
-    if (!nmp->opts) {
-	msg = TUPLE2(hp, what, node);
-#ifdef DEBUG
-	hp += 3;
-#endif
-    }
-    else {
-	Eterm tup;
-	Eterm info = NIL;
+    mdp = erts_monitor_to_data(omon);
 
-	if (nmp->opts & (ERTS_NODES_MON_OPT_TYPE_VISIBLE
-			 | ERTS_NODES_MON_OPT_TYPE_HIDDEN)) {
+    erts_mtx_lock(&nodes_monitors_mtx);
+    ASSERT(erts_monitor_is_in_table(&mdp->target));
+    ASSERT(no_nodes_monitors > 0);
+    no_nodes_monitors--;
+    erts_monitor_list_delete(&nodes_monitors, &mdp->target);
+    erts_mtx_unlock(&nodes_monitors_mtx);
+    erts_monitor_release_both(mdp);
+}
 
-	    tup = TUPLE2(hp, am_node_type, type);
-	    hp += 3;
-	    info = CONS(hp, tup, info);
-	    hp += 2;
-	}
+typedef struct {
+    Eterm pid;
+    Eterm options;
+} ErtsNodesMonitorData;
 
-	if (what == am_nodedown
-	    && (nmp->opts & ERTS_NODES_MON_OPT_DOWN_REASON)) {
-	    Eterm rsn_cpy;
-	    
-	    if (is_immed(reason))
-		rsn_cpy = reason;
-	    else {
-		Eterm rsn_sz = size_object(reason);
-		rsn_cpy = copy_struct(reason, rsn_sz, &hp, ohp);
-	    }
+typedef struct {
+    ErtsNodesMonitorData *nmdp;
+    Uint i;
+} ErtsNodesMonitorContext;
 
-	    tup = TUPLE2(hp, am_nodedown_reason, rsn_cpy);
-	    hp += 3;
-	    info = CONS(hp, tup, info);
-	    hp += 2;
-	}
+static void
+save_nodes_monitor(ErtsMonitor *mon, void *vctxt)
+{
+    ErtsNodesMonitorContext *ctxt = vctxt;
+    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
 
-	msg = TUPLE3(hp, what, node, info);
-#ifdef DEBUG
-	hp += 4;
-#endif
-    }
+    ASSERT(erts_monitor_is_target(mon));
+    ASSERT(mon->type == ERTS_MON_TYPE_NODES);
+
+    ctxt->nmdp[ctxt->i].pid = mon->other.item;
+    ctxt->nmdp[ctxt->i].options = mdp->origin.other.item;
 
-    ASSERT(hend == hp);
-    erts_queue_message(rp, *rp_locksp, mp, msg, am_system);
+    ctxt->i++;
 }
 
 static void
 send_nodes_mon_msgs(Process *c_p, Eterm what, Eterm node, Eterm type, Eterm reason)
 {
-    ErtsNodesMonitor *nmp;
-    ErtsProcLocks rp_locks = 0; /* Init to shut up false warning */
-    Process *rp = NULL;
+    Uint opts;
+    Uint i, no, reason_size;
+    ErtsNodesMonitorData def_buf[100];
+    ErtsNodesMonitorData *nmdp = &def_buf[0];
+    ErtsNodesMonitorContext ctxt;
 
     ASSERT(is_immed(what));
     ASSERT(is_immed(node));
@@ -4180,31 +4157,44 @@ send_nodes_mon_msgs(Process *c_p, Eterm what, Eterm node, Eterm type, Eterm reas
     }
 #endif
 
-    ERTS_LC_ASSERT(!c_p
-		       || (erts_proc_lc_my_proc_locks(c_p)
-			   == ERTS_PROC_LOCK_MAIN));
+    ctxt.i = 0;
+
+    reason_size = is_immed(reason) ? 0 : size_object(reason);
+
     erts_mtx_lock(&nodes_monitors_mtx);
+    if (no_nodes_monitors > sizeof(def_buf)/sizeof(def_buf[0]))
+        nmdp = erts_alloc(ERTS_ALC_T_TMP,
+                          no_nodes_monitors*sizeof(ErtsNodesMonitorData));
+    ctxt.nmdp = nmdp;
+    erts_monitor_list_foreach(nodes_monitors,
+                              save_nodes_monitor,
+                              (void *) &ctxt);
+    
+    ASSERT(ctxt.i == no_nodes_monitors);
+    no = no_nodes_monitors;
 
-    for (nmp = nodes_monitors; nmp; nmp = nmp->next) {
-	int i;
-	Uint16 no;
-	Uint sz;
+    erts_mtx_unlock(&nodes_monitors_mtx);
 
-	ASSERT(nmp->proc != NULL);
+    for (i = 0; i < no; i++) {
+        Eterm tmp_heap[3+2+3+2+4 /* max need */];
+        Eterm *hp, msg;
+        Uint hsz;
 
-	if (!nmp->opts) {
+        ASSERT(is_small(nmdp[i].options));
+        opts = (Uint) signed_val(nmdp[i].options);
+	if (!opts) {
 	    if (type != am_visible)
 		continue;
 	}
 	else {
 	    switch (type) {
 	    case am_hidden:
-		if (!(nmp->opts & ERTS_NODES_MON_OPT_TYPE_HIDDEN))
+		if (!(opts & ERTS_NODES_MON_OPT_TYPE_HIDDEN))
 		    continue;
 		break;
 	    case am_visible:
-		if ((nmp->opts & ERTS_NODES_MON_OPT_TYPES)
-		    && !(nmp->opts & ERTS_NODES_MON_OPT_TYPE_VISIBLE))
+		if ((opts & ERTS_NODES_MON_OPT_TYPES)
+		    && !(opts & ERTS_NODES_MON_OPT_TYPE_VISIBLE))
 		    continue;
 		break;
 	    default:
@@ -4212,342 +4202,162 @@ send_nodes_mon_msgs(Process *c_p, Eterm what, Eterm node, Eterm type, Eterm reas
 	    }
 	}
 
-	if (rp != nmp->proc) {
-	    if (rp) {
-		if (rp == c_p)
-		    rp_locks &= ~ERTS_PROC_LOCK_MAIN;
-		erts_proc_unlock(rp, rp_locks);
-	    }
+        hsz = 0;
+        hp = &tmp_heap[0];
 
-	    rp = nmp->proc;
-	    rp_locks = 0;
-	    if (rp == c_p)
-		rp_locks |= ERTS_PROC_LOCK_MAIN;
-	}
-
-	ASSERT(rp);
-
-	sz = nodes_mon_msg_sz(nmp, what, reason);
+        if (!opts) {
+            msg = TUPLE2(hp, what, node);
+            hp += 3;
+        }
+        else {
+            Eterm tup;
+            Eterm info = NIL;
 
-	for (i = 0, no = nmp->no; i < no; i++)
-	    send_nodes_mon_msg(rp,
-			       &rp_locks,
-			       nmp,
-			       node,
-			       what,
-			       type,
-			       reason,
-			       sz);
-    }
+            if (opts & (ERTS_NODES_MON_OPT_TYPE_VISIBLE
+                        | ERTS_NODES_MON_OPT_TYPE_HIDDEN)) {
 
-    if (rp) {
-	if (rp == c_p)
-	    rp_locks &= ~ERTS_PROC_LOCK_MAIN;
-	erts_proc_unlock(rp, rp_locks);
-    }
+                tup = TUPLE2(hp, am_node_type, type);
+                hp += 3;
+                info = CONS(hp, tup, info);
+                hp += 2;
+            }
 
-    erts_mtx_unlock(&nodes_monitors_mtx);
-}
+            if (what == am_nodedown
+                && (opts & ERTS_NODES_MON_OPT_DOWN_REASON)) {
+                hsz += reason_size;
+                tup = TUPLE2(hp, am_nodedown_reason, reason);
+                hp += 3;
+                info = CONS(hp, tup, info);
+                hp += 2;
+            }
 
-static Eterm
-insert_nodes_monitor(Process *c_p, Uint32 opts)
-{
-    Uint16 no = 1;
-    Eterm res = am_false;
-    ErtsNodesMonitor *xnmp, *nmp;
+            msg = TUPLE3(hp, what, node, info);
+            hp += 4;
+        }
 
-    ERTS_LC_ASSERT(erts_lc_mtx_is_locked(&nodes_monitors_mtx));
-    ERTS_LC_ASSERT(erts_proc_lc_my_proc_locks(c_p) & ERTS_PROC_LOCK_MAIN);
+        ASSERT(hp - &tmp_heap[0] <= sizeof(tmp_heap)/sizeof(tmp_heap[0]));
 
-    xnmp = c_p->nodes_monitors;
-    if (xnmp) {
-	ASSERT(!xnmp->prev || xnmp->prev->proc != c_p);
+        hsz += hp - &tmp_heap[0];
 
-	while (1) {
-	    ASSERT(xnmp->proc == c_p);
-	    if (xnmp->opts == opts)
-		break;
-	    if (!xnmp->next || xnmp->next->proc != c_p)
-		break;
-	    xnmp = xnmp->next;
-	}
-	ASSERT(xnmp);
-	ASSERT(xnmp->proc == c_p);
-	ASSERT(xnmp->opts == opts
-	       || !xnmp->next
-	       || xnmp->next->proc != c_p);
-
-	if (xnmp->opts != opts)
-	    goto alloc_new;
-	else {
-	    res = am_true;
-	    no = xnmp->no++;
-	    if (!xnmp->no) {
-		/*
-		 * 'no' wrapped; transfer all prevous monitors to new
-		 * element (which will be the next element in the list)
-		 * and set this to one...
-		 */
-		xnmp->no = 1;
-		goto alloc_new;
-	    }
-	}
+        erts_proc_sig_send_persistent_monitor_msg(ERTS_MON_TYPE_NODES,
+                                                  nmdp[i].options,
+                                                  am_system,
+                                                  nmdp[i].pid,
+                                                  msg,
+                                                  hsz);
     }
-    else {
-    alloc_new:
-	nmp = erts_alloc(ERTS_ALC_T_NODES_MON, sizeof(ErtsNodesMonitor));
-	nmp->proc = c_p;
-	nmp->opts = opts;
-	nmp->no = no;
-
-	if (xnmp) {
-	    ASSERT(nodes_monitors);
-	    ASSERT(c_p->nodes_monitors);
-	    nmp->next = xnmp->next;
-	    nmp->prev = xnmp;
-	    xnmp->next = nmp;
-	    if (nmp->next) {
-		ASSERT(nodes_monitors_end != xnmp);
-		ASSERT(nmp->next->prev == xnmp);
-		nmp->next->prev = nmp;
-	    }
-	    else {
-		ASSERT(nodes_monitors_end == xnmp);
-		nodes_monitors_end = nmp;
-	    }
-	}
-	else {
-	    ASSERT(!c_p->nodes_monitors);
-	    c_p->nodes_monitors = nmp;
-	    nmp->next = NULL;
-	    nmp->prev = nodes_monitors_end;
-	    if (nodes_monitors_end) {
-		ASSERT(nodes_monitors);
-		nodes_monitors_end->next = nmp;
-	    }
-	    else {
-		ASSERT(!nodes_monitors);
-		nodes_monitors = nmp;
-	    }
-	    nodes_monitors_end = nmp;
-	}
-    }
-    return res;
-}
 
-static Eterm
-remove_nodes_monitors(Process *c_p, Uint32 opts, int all)
-{
-    Eterm res = am_false;
-    ErtsNodesMonitor *nmp;
-
-    ERTS_LC_ASSERT(erts_lc_mtx_is_locked(&nodes_monitors_mtx));
-    ERTS_LC_ASSERT(erts_proc_lc_my_proc_locks(c_p) & ERTS_PROC_LOCK_MAIN);
-
-    nmp = c_p->nodes_monitors;
-    ASSERT(!nmp || !nmp->prev || nmp->prev->proc != c_p);
-
-    while (nmp && nmp->proc == c_p) {
-	if (!all && nmp->opts != opts)
-	    nmp = nmp->next;
-	else { /* if (all || nmp->opts == opts) */
-	    ErtsNodesMonitor *free_nmp;
-	    res = am_true;
-	    if (nmp->prev) {
-		ASSERT(nodes_monitors != nmp);
-		nmp->prev->next = nmp->next;
-	    }
-	    else {
-		ASSERT(nodes_monitors == nmp);
-		nodes_monitors = nmp->next;
-	    }
-	    if (nmp->next) {
-		ASSERT(nodes_monitors_end != nmp);
-		nmp->next->prev = nmp->prev;
-	    }
-	    else {
-		ASSERT(nodes_monitors_end == nmp);
-		nodes_monitors_end = nmp->prev;
-	    }
-	    free_nmp = nmp;
-	    nmp = nmp->next;
-	    if (c_p->nodes_monitors == free_nmp)
-		c_p->nodes_monitors = nmp && nmp->proc == c_p ? nmp : NULL;
-	    erts_free(ERTS_ALC_T_NODES_MON, free_nmp);
-	}
-    }
-    
-    ASSERT(!all || !c_p->nodes_monitors);
-    return res;
+    if (nmdp != &def_buf[0])
+        erts_free(ERTS_ALC_T_TMP, nmdp);
 }
+                           
 
-void
-erts_delete_nodes_monitors(Process *c_p, ErtsProcLocks locks)
-{
-#if defined(ERTS_ENABLE_LOCK_CHECK)
-    if (c_p) {
-	ErtsProcLocks might_unlock = locks & ~ERTS_PROC_LOCK_MAIN;
-	if (might_unlock)
-	    erts_proc_lc_might_unlock(c_p, might_unlock);
-    }
-#endif
-    if (erts_mtx_trylock(&nodes_monitors_mtx) == EBUSY) {
-	ErtsProcLocks unlock_locks = locks & ~ERTS_PROC_LOCK_MAIN;
-	if (c_p && unlock_locks)
-	    erts_proc_unlock(c_p, unlock_locks);
-	erts_mtx_lock(&nodes_monitors_mtx);
-	if (c_p && unlock_locks)
-	    erts_proc_lock(c_p, unlock_locks);
-    }
-    remove_nodes_monitors(c_p, 0, 1);
-    erts_mtx_unlock(&nodes_monitors_mtx);
-}
-
-Eterm
-erts_monitor_nodes(Process *c_p, Eterm on, Eterm olist)
-{
+typedef struct {
+    Eterm **hpp;
+    Uint *szp;
     Eterm res;
-    Eterm opts_list = olist;
-    Uint16 opts = (Uint16) 0;
-
-    ASSERT(c_p);
-    ERTS_LC_ASSERT(erts_proc_lc_my_proc_locks(c_p) == ERTS_PROC_LOCK_MAIN);
-
-    if (on != am_true && on != am_false)
-	return THE_NON_VALUE;
-
-    if (is_not_nil(opts_list)) {
-	int all = 0, visible = 0, hidden = 0;
-
-	while (is_list(opts_list)) {
-	    Eterm *cp = list_val(opts_list);
-	    Eterm opt = CAR(cp);
-	    opts_list = CDR(cp);
-	    if (opt == am_nodedown_reason)
-		opts |= ERTS_NODES_MON_OPT_DOWN_REASON;
-	    else if (is_tuple(opt)) {
-		Eterm* tp = tuple_val(opt);
-		if (arityval(tp[0]) != 2)
-		    return THE_NON_VALUE;
-		switch (tp[1]) {
-		case am_node_type:
-		    switch (tp[2]) {
-		    case am_visible:
-			if (hidden || all)
-			    return THE_NON_VALUE;
-			opts |= ERTS_NODES_MON_OPT_TYPE_VISIBLE;
-			visible = 1;
-			break;
-		    case am_hidden:
-			if (visible || all)
-			    return THE_NON_VALUE;
-			opts |= ERTS_NODES_MON_OPT_TYPE_HIDDEN;
-			hidden = 1;
-			break;
-		    case am_all:
-			if (visible || hidden)
-			    return THE_NON_VALUE;
-			opts |= ERTS_NODES_MON_OPT_TYPES;
-			all = 1;
-			break;
-		    default:
-			return THE_NON_VALUE;
-		    }
-		    break;
-		default:
-		    return THE_NON_VALUE;
-		}
-	    }
-	    else {
-		return THE_NON_VALUE;
-	    }
-	}
-
-	if (is_not_nil(opts_list))
-	    return THE_NON_VALUE;
-    }
+} ErtsNodesMonitorInfoContext;
 
-    erts_mtx_lock(&nodes_monitors_mtx);
 
-    if (on == am_true)
-	res = insert_nodes_monitor(c_p, opts);
-    else
-	res = remove_nodes_monitors(c_p, opts, 0);
-
-    erts_mtx_unlock(&nodes_monitors_mtx);
-
-    return res;
+static void
+nodes_monitor_info(ErtsMonitor *mon, void *vctxt)
+{
+    ErtsMonitorDataExtended *mdep;
+    ErtsNodesMonitorInfoContext *ctxt = vctxt;
+    Uint no, i, opts, *szp;
+    Eterm **hpp, res;
+
+    hpp = ctxt->hpp;
+    szp = ctxt->szp;
+    res = ctxt->res;
+
+    ASSERT(erts_monitor_is_target(mon));
+    ASSERT(mon->type == ERTS_MON_TYPE_NODES);
+    mdep = (ErtsMonitorDataExtended *) erts_monitor_to_data(mon);
+    no = mdep->u.refc;
+
+    ASSERT(is_small(mdep->md.origin.other.item));
+    opts = (Uint) signed_val(mdep->md.origin.other.item);
+
+    for (i = 0; i < no; i++) {
+        Eterm olist = NIL;
+        if (opts & ERTS_NODES_MON_OPT_TYPES) {
+            Eterm type;
+            switch (opts & ERTS_NODES_MON_OPT_TYPES) {
+            case ERTS_NODES_MON_OPT_TYPES:        type = am_all;     break;
+            case ERTS_NODES_MON_OPT_TYPE_VISIBLE: type = am_visible; break;
+            case ERTS_NODES_MON_OPT_TYPE_HIDDEN:  type = am_hidden;  break;
+            default: erts_exit(ERTS_ABORT_EXIT, "Bad node type found\n");
+            }
+            olist = erts_bld_cons(hpp, szp, 
+                                  erts_bld_tuple(hpp, szp, 2,
+                                                 am_node_type,
+                                                 type),
+                                  olist);
+        }
+        if (opts & ERTS_NODES_MON_OPT_DOWN_REASON)
+            olist = erts_bld_cons(hpp, szp, am_nodedown_reason, olist);
+        res = erts_bld_cons(hpp, szp,
+                            erts_bld_tuple(hpp, szp, 2,
+                                           mon->other.item,
+                                           olist),
+                            res);
+    }
+
+    ctxt->hpp = hpp;
+    ctxt->szp = szp;
+    ctxt->res = res;
 }
 
-/*
- * Note, this function is only used for debuging.
- */
-
 Eterm
 erts_processes_monitoring_nodes(Process *c_p)
 {
-    ErtsNodesMonitor *nmp;
-    Eterm res;
+    /*
+     * Note, this function is only used for debugging.
+     */
+    ErtsNodesMonitorInfoContext ctxt;
     Eterm *hp;
-    Eterm **hpp;
     Uint sz;
-    Uint *szp;
 #ifdef DEBUG
     Eterm *hend;
 #endif
 
     ASSERT(c_p);
     ERTS_LC_ASSERT(erts_proc_lc_my_proc_locks(c_p) == ERTS_PROC_LOCK_MAIN);
+
+    erts_proc_unlock(c_p, ERTS_PROC_LOCK_MAIN);
+    erts_thr_progress_block();
+
     erts_mtx_lock(&nodes_monitors_mtx);
 
     sz = 0;
-    szp = &sz;
-    hpp = NULL;
+    ctxt.szp = &sz;
+    ctxt.hpp = NULL;
 
- bld_result:
-    res = NIL;
-
-    for (nmp = nodes_monitors_end; nmp; nmp = nmp->prev) {
-	Uint16 i;
-	for (i = 0; i < nmp->no; i++) {
-	    Eterm olist = NIL;
-	    if (nmp->opts & ERTS_NODES_MON_OPT_TYPES) {
-		Eterm type;
-		switch (nmp->opts & ERTS_NODES_MON_OPT_TYPES) {
-		case ERTS_NODES_MON_OPT_TYPES:        type = am_all;     break;
-		case ERTS_NODES_MON_OPT_TYPE_VISIBLE: type = am_visible; break;
-		case ERTS_NODES_MON_OPT_TYPE_HIDDEN:  type = am_hidden;  break;
-		default: erts_exit(ERTS_ABORT_EXIT, "Bad node type found\n");
-		}
-		olist = erts_bld_cons(hpp, szp, 
-				      erts_bld_tuple(hpp, szp, 2,
-						     am_node_type,
-						     type),
-				      olist);
-	    }
-	    if (nmp->opts & ERTS_NODES_MON_OPT_DOWN_REASON)
-		olist = erts_bld_cons(hpp, szp, am_nodedown_reason, olist);
-	    res = erts_bld_cons(hpp, szp,
-				erts_bld_tuple(hpp, szp, 2,
-					       nmp->proc->common.id,
-					       olist),
-				res);
-	}
-    }
+    while (1) {
+        ctxt.res = NIL;
+
+        erts_monitor_list_foreach(nodes_monitors,
+                                  nodes_monitor_info,
+                                  (void *) &ctxt);
+
+        if (ctxt.hpp)
+            break;
 
-    if (!hpp) {
 	hp = HAlloc(c_p, sz);
 #ifdef DEBUG
 	hend = hp + sz;
 #endif
-	hpp = &hp;
-	szp = NULL;
-	goto bld_result;
+	ctxt.hpp = &hp;
+	ctxt.szp = NULL;
     }
 
     ASSERT(hp == hend);
 
     erts_mtx_unlock(&nodes_monitors_mtx);
 
-    return res;
+    erts_thr_progress_unblock();
+    erts_proc_lock(c_p, ERTS_PROC_LOCK_MAIN);
+
+    return ctxt.res;
 }
diff --git a/erts/emulator/beam/dist.h b/erts/emulator/beam/dist.h
index b1b7ce9c78..c608fef816 100644
--- a/erts/emulator/beam/dist.h
+++ b/erts/emulator/beam/dist.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1996-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1996-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -120,7 +120,6 @@
 
 /* distribution trap functions */
 extern Export* dmonitor_node_trap;
-extern Export* dmonitor_p_trap;
 
 typedef enum {
     ERTS_DSP_NO_LOCK,
@@ -274,58 +273,13 @@ void erts_schedule_dist_command(Port *prt, DistEntry *dist_entry)
 
 #endif
 
-typedef struct {
-    ErtsLink *d_lnk;
-    ErtsLink *d_sub_lnk;
-} ErtsDistLinkData;
-
-ERTS_GLB_INLINE void erts_remove_dist_link(ErtsDistLinkData *,
-					   Eterm,
-					   Eterm,
-					   DistEntry *);
-ERTS_GLB_INLINE int erts_was_dist_link_removed(ErtsDistLinkData *);
-ERTS_GLB_INLINE void erts_destroy_dist_link(ErtsDistLinkData *);
-
-#if ERTS_GLB_INLINE_INCL_FUNC_DEF
-
-ERTS_GLB_INLINE void
-erts_remove_dist_link(ErtsDistLinkData *dldp,
-		      Eterm lid,
-		      Eterm rid,
-		      DistEntry *dep)
-{
-    erts_de_links_lock(dep);
-    dldp->d_lnk = erts_lookup_link(dep->nlinks, lid);
-    if (!dldp->d_lnk)
-	dldp->d_sub_lnk = NULL;
-    else {
-	dldp->d_sub_lnk = erts_remove_link(&ERTS_LINK_ROOT(dldp->d_lnk), rid);
-	dldp->d_lnk = (ERTS_LINK_ROOT(dldp->d_lnk)
-		       ? NULL
-		       : erts_remove_link(&dep->nlinks, lid));
-    }
-    erts_de_links_unlock(dep);
-}
-
-ERTS_GLB_INLINE int
-erts_was_dist_link_removed(ErtsDistLinkData *dldp)
-{
-    return dldp->d_sub_lnk != NULL;
-}
-
-ERTS_GLB_INLINE void
-erts_destroy_dist_link(ErtsDistLinkData *dldp)
-{
-    if (dldp->d_lnk)
-	erts_destroy_link(dldp->d_lnk);
-    if (dldp->d_sub_lnk)
-	erts_destroy_link(dldp->d_sub_lnk);	
-}
-
+#ifdef DEBUG
+#define ERTS_DBG_CHK_NO_DIST_LNK(D, R, L) \
+    erts_dbg_chk_no_dist_proc_link((D), (R), (L))
+#else
+#define ERTS_DBG_CHK_NO_DIST_LNK(D, R, L)
 #endif
 
-
-
 /* Define for testing */
 /* #define EXTREME_TTB_TRAPPING 1 */
 
diff --git a/erts/emulator/beam/erl_alloc.c b/erts/emulator/beam/erl_alloc.c
index f7f5506a72..061b9df627 100644
--- a/erts/emulator/beam/erl_alloc.c
+++ b/erts/emulator/beam/erl_alloc.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2002-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2002-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -40,7 +40,7 @@
 #include "erl_bits.h"
 #include "erl_instrument.h"
 #include "erl_mseg.h"
-#include "erl_monitors.h"
+#include "erl_monitor_link.h"
 #include "erl_hl_timer.h"
 #include "erl_cpu_topology.h"
 #include "erl_thr_queue.h"
@@ -636,10 +636,10 @@ erts_alloc_init(int *argc, char **argv, ErtsAllocInitOpts *eaiop)
 
     fix_type_sizes[ERTS_ALC_FIX_TYPE_IX(ERTS_ALC_T_PROC)]
 	= sizeof(Process);
-    fix_type_sizes[ERTS_ALC_FIX_TYPE_IX(ERTS_ALC_T_MONITOR_SH)]
-	= ERTS_MONITOR_SH_SIZE * sizeof(Uint);
-    fix_type_sizes[ERTS_ALC_FIX_TYPE_IX(ERTS_ALC_T_NLINK_SH)]
-	= ERTS_LINK_SH_SIZE * sizeof(Uint);
+    fix_type_sizes[ERTS_ALC_FIX_TYPE_IX(ERTS_ALC_T_MONITOR)]
+	= sizeof(ErtsMonitorDataHeap);
+    fix_type_sizes[ERTS_ALC_FIX_TYPE_IX(ERTS_ALC_T_LINK)]
+	= sizeof(ErtsLinkData);
     fix_type_sizes[ERTS_ALC_FIX_TYPE_IX(ERTS_ALC_T_DRV_SEL_D_STATE)]
 	= sizeof(ErtsDrvSelectDataState);
     fix_type_sizes[ERTS_ALC_FIX_TYPE_IX(ERTS_ALC_T_NIF_SEL_D_STATE)]
@@ -2370,7 +2370,6 @@ erts_memory(fmtfn_t *print_to_p, void *print_to_arg, void *proc, Eterm earg)
 	}
 	tmp += erts_ptab_mem_size(&erts_proc);
 	tmp += erts_bif_timer_memory_size();
-	tmp += erts_tot_link_lh_size();
 
 	size.processes = size.processes_used = tmp;
 
@@ -2381,12 +2380,11 @@ erts_memory(fmtfn_t *print_to_p, void *print_to_arg, void *proc, Eterm earg)
 	add_fix_values(&size.processes,
 		       &size.processes_used,
 		       fi,
-		       ERTS_ALC_T_MONITOR_SH);
-
+		       ERTS_ALC_T_MONITOR);
 	add_fix_values(&size.processes,
 		       &size.processes_used,
 		       fi,
-		       ERTS_ALC_T_NLINK_SH);
+		       ERTS_ALC_T_LINK);
 	add_fix_values(&size.processes,
 		       &size.processes_used,
 		       fi,
@@ -2617,11 +2615,6 @@ erts_allocated_areas(fmtfn_t *print_to_p, void *print_to_arg, void *proc)
     i++;
 
     values[i].arity = 2;
-    values[i].name = "link_lh";
-    values[i].ui[0] = erts_tot_link_lh_size();
-    i++;
-
-    values[i].arity = 2;
     values[i].name = "process_table";
     values[i].ui[0] = erts_ptab_mem_size(&erts_proc);
     i++;
diff --git a/erts/emulator/beam/erl_alloc.types b/erts/emulator/beam/erl_alloc.types
index 8107f133aa..4a6a19b210 100644
--- a/erts/emulator/beam/erl_alloc.types
+++ b/erts/emulator/beam/erl_alloc.types
@@ -1,7 +1,7 @@
 #
 # %CopyrightBegin%
 #
-# Copyright Ericsson AB 2003-2017. All Rights Reserved.
+# Copyright Ericsson AB 2003-2018. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -282,6 +282,11 @@ type	THR_PRGR_IDATA	LONG_LIVED	SYSTEM		thr_prgr_internal_data
 type	THR_PRGR_DATA	LONG_LIVED	SYSTEM		thr_prgr_data
 type	T_THR_PRGR_DATA	SHORT_LIVED	SYSTEM		temp_thr_prgr_data
 type	RELEASE_LAREA	SHORT_LIVED	SYSTEM		release_literal_area
+type	SIG_DATA	SHORT_LIVED	PROCESSES	signal_data
+type	DIST_DEMONITOR	SHORT_LIVED	PROCESSES	dist_demonitor
+type	CML_CLEANUP	SHORT_LIVED	SYSTEM		connection_ml_cleanup
+type	ML_YIELD_STATE	SHORT_LIVED	SYSTEM		monitor_link_yield_state
+type	ML_DIST		STANDARD	SYSTEM		monitor_link_dist
 
 type	ENVIRONMENT	SYSTEM		SYSTEM		environment
 
@@ -326,8 +331,8 @@ type    LCNT_VECTOR SHORT_LIVED SYSTEM lcnt_sample_vector
 type	DEBUG	        SHORT_LIVED	SYSTEM          debugging
 
 type	DDLL_PROCESS	STANDARD	SYSTEM		ddll_processes
-type	MONITOR_LH	STANDARD	PROCESSES	monitor_lh
-type	NLINK_LH	STANDARD	PROCESSES	nlink_lh
+type	MONITOR_EXT	STANDARD	PROCESSES	monitor_extended
+type	LINK_EXT	STANDARD	PROCESSES	link_extended
 type	CODE		LONG_LIVED	CODE		code
 type	LITERAL		LITERAL 	CODE		literal
 type	LITERAL_REF	SHORT_LIVED	CODE		literal_area_ref
@@ -340,8 +345,8 @@ type  	LL_TEMP_TERM 	LONG_LIVED	SYSTEM		ll_temp_term
 type	NIF_TRAP_EXPORT	STANDARD	PROCESSES	nif_trap_export_entry
 type	NIF_EXP_TRACE	FIXED_SIZE	PROCESSES	nif_export_trace
 type	EXPORT		LONG_LIVED	CODE		export_entry
-type	MONITOR_SH	FIXED_SIZE	PROCESSES	monitor_sh
-type	NLINK_SH	FIXED_SIZE	PROCESSES	nlink_sh
+type	MONITOR		FIXED_SIZE	PROCESSES	monitor
+type	LINK		FIXED_SIZE	PROCESSES	link
 type	AINFO_REQ	SHORT_LIVED	SYSTEM		alloc_info_request
 type	SCHED_WTIME_REQ	SHORT_LIVED	SYSTEM		sched_wall_time_request
 type	GC_INFO_REQ	SHORT_LIVED	SYSTEM		gc_info_request
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 3f9b584c2e..6106cfdcfd 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1999-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1999-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -50,6 +50,7 @@
 #define ERTS_PTAB_WANT_DEBUG_FUNCS__
 #include "erl_ptab.h"
 #include "erl_time.h"
+#include "erl_proc_sig_queue.h"
 #ifdef HIPE
 #include "hipe_arch.h"
 #endif
@@ -211,21 +212,27 @@ bld_magic_ref_bin_list(Uint **hpp, Uint *szp, ErlOffHeap* oh)
   make_monitor_list:
   returns a list of records..
   -record(erl_monitor, {
-            type, % MON_ORIGIN or MON_TARGET (1 or 3)
-	    ref,
+            type, % process | port | time_offset | dist_process | resource
+                  % | node | nodes | suspend
+            dir, % origin | target
+	    ref, % reference or []
 	    pid, % Process or nodename
-	    name % registered name or []
+	    extra % registered name, integer or []
           }).
 */
 
 static void do_calc_mon_size(ErtsMonitor *mon, void *vpsz)
 {
+    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
     Uint *psz = vpsz;
-    *psz += NC_HEAP_SIZE(mon->ref);
-    *psz += (mon->type == MON_NIF_TARGET ?
-	     erts_resource_ref_size(mon->u.resource) :
-	     (is_immed(mon->u.pid) ? 0 : NC_HEAP_SIZE(mon->u.pid)));
-    *psz += 8; /* CONS + 5-tuple */ 
+    *psz += is_immed(mdp->ref) ? 0 : NC_HEAP_SIZE(mdp->ref);
+
+    if (mon->type == ERTS_MON_TYPE_RESOURCE && erts_monitor_is_target(mon))
+        *psz += erts_resource_ref_size(mon->other.ptr);
+    else
+        *psz += is_immed(mon->other.item) ? 0 : NC_HEAP_SIZE(mon->other.item);
+
+    *psz += 9; /* CONS + 6-tuple */ 
 }
 
 typedef struct {
@@ -237,35 +244,97 @@ typedef struct {
 
 static void do_make_one_mon_element(ErtsMonitor *mon, void * vpmlc)
 {
+    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
     MonListContext *pmlc = vpmlc;
-    Eterm tup;
-    Eterm r = STORE_NC(&(pmlc->hp), &MSO(pmlc->p), mon->ref);
-    Eterm p = (mon->type == MON_NIF_TARGET ?
-	       erts_bld_resource_ref(&(pmlc->hp), &MSO(pmlc->p), mon->u.resource)
-	       : (is_immed(mon->u.pid) ? mon->u.pid
-		  : STORE_NC(&(pmlc->hp), &MSO(pmlc->p), mon->u.pid)));
-    tup = TUPLE5(pmlc->hp, pmlc->tag, make_small(mon->type), r, p, mon->name);
-    pmlc->hp += 6;
+    Eterm tup, t, d, r, p, x;
+
+    r = is_immed(mdp->ref) ? mdp->ref : STORE_NC(&(pmlc->hp), &MSO(pmlc->p), mdp->ref);
+    if (mon->type == ERTS_MON_TYPE_RESOURCE && erts_monitor_is_target(mon))
+        p = erts_bld_resource_ref(&(pmlc->hp), &MSO(pmlc->p), mon->other.ptr);
+    else
+        p = (is_immed(mon->other.item)
+             ? mon->other.item
+             : STORE_NC(&(pmlc->hp), &MSO(pmlc->p), mon->other.item));
+
+    if (mon->flags & ERTS_ML_FLG_NAME)
+        x = ((ErtsMonitorDataExtended *) mdp)->u.name;
+    else if (erts_monitor_is_target(mon))
+        x = NIL;
+    else if (mon->type == ERTS_MON_TYPE_NODE || mon->type == ERTS_MON_TYPE_NODES)
+        x = make_small(((ErtsMonitorDataExtended *) mdp)->u.refc);
+    else
+        x = NIL;
+
+    switch (mon->type) {
+    case ERTS_MON_TYPE_PROC:
+        t = am_process;
+        break;
+    case ERTS_MON_TYPE_PORT:
+        t = am_port;
+        break;
+    case ERTS_MON_TYPE_TIME_OFFSET:
+        t = am_time_offset;
+        break;
+    case ERTS_MON_TYPE_DIST_PROC: {
+        ERTS_DECL_AM(dist_process);
+        t = AM_dist_process;
+        break;
+    }
+    case ERTS_MON_TYPE_RESOURCE: {
+        ERTS_DECL_AM(resource);
+        t = AM_resource;
+        break;
+    }
+    case ERTS_MON_TYPE_NODE:
+        t = am_node;
+        break;
+    case ERTS_MON_TYPE_NODES: {
+        ERTS_DECL_AM(nodes);
+        t = AM_nodes;
+        break;
+    }
+    case ERTS_MON_TYPE_SUSPEND:
+        t = am_suspend;
+        break;
+    default:
+        ERTS_INTERNAL_ERROR("Unknown monitor type");
+        t = am_error;
+        break;
+    }
+    if (erts_monitor_is_target(mon)) {
+        ERTS_DECL_AM(target);
+        d = AM_target;
+    }
+    else {
+        ERTS_DECL_AM(origin);
+        d = AM_origin;
+    }
+    tup = TUPLE6(pmlc->hp, pmlc->tag, t, d, r, p, x);
+    pmlc->hp += 7;
     pmlc->res = CONS(pmlc->hp, tup, pmlc->res);
     pmlc->hp += 2;
 }
 
 static Eterm 
-make_monitor_list(Process *p, ErtsMonitor *root)
+make_monitor_list(Process *p, int tree, ErtsMonitor *root, Eterm tail)
 {
     DECL_AM(erl_monitor);
     Uint sz = 0;
     MonListContext mlc;
+    void (*foreach)(ErtsMonitor *,
+                    void (*)(ErtsMonitor *, void *),
+                    void *);
 
-    erts_doforall_monitors(root, &do_calc_mon_size, &sz);
-    if (sz == 0) {
-	return NIL;
-    }
+    foreach = tree ? erts_monitor_tree_foreach : erts_monitor_list_foreach;
+
+    (*foreach)(root, do_calc_mon_size, &sz);
+    if (sz == 0)
+	return tail;
     mlc.p = p;
     mlc.hp = HAlloc(p,sz);
-    mlc.res = NIL;
+    mlc.res = tail;
     mlc.tag = AM_erl_monitor;
-    erts_doforall_monitors(root, &do_make_one_mon_element, &mlc);
+    (*foreach)(root, do_make_one_mon_element, &mlc);
     return mlc.res;
 }
 
@@ -273,20 +342,22 @@ make_monitor_list(Process *p, ErtsMonitor *root)
   make_link_list:
   returns a list of records..
   -record(erl_link, {
-            type, % LINK_NODE or LINK_PID (1 or 3)
-	    pid, % Process or nodename
-	    targets % List of erl_link's or nil
+            type, % process | port | dist_process
+	    pid, % Process or port
+            id % (address)
           }).
 */
 
-static void do_calc_lnk_size(ErtsLink *lnk, void *vpsz)
+static void calc_lnk_size(ErtsLink *lnk, void *vpsz)
 {
     Uint *psz = vpsz;
-    *psz += is_immed(lnk->pid) ? 0 : NC_HEAP_SIZE(lnk->pid);
-    if (lnk->type != LINK_NODE && ERTS_LINK_ROOT(lnk) != NULL) { 
-	/* Node links use this pointer as ref counter... */
-	erts_doforall_links(ERTS_LINK_ROOT(lnk),&do_calc_lnk_size,vpsz);
-    }
+    Uint sz = 0;
+    ErtsLinkData *ldp = erts_link_to_data(lnk);
+
+    (void) erts_bld_uword(NULL, &sz, (UWord) ldp);
+
+    *psz += sz;
+    *psz += is_immed(lnk->other.item) ? 0 : size_object(lnk->other.item);
     *psz += 7; /* CONS + 4-tuple */ 
 }
 
@@ -297,37 +368,58 @@ typedef struct {
     Eterm tag;
 } LnkListContext;
 
-static void do_make_one_lnk_element(ErtsLink *lnk, void * vpllc)
+static void make_one_lnk_element(ErtsLink *lnk, void * vpllc)
 {
     LnkListContext *pllc = vpllc;
-    Eterm tup;
-    Eterm old_res, targets = NIL;
-    Eterm p = (is_immed(lnk->pid)
-	       ? lnk->pid
-	       : STORE_NC(&(pllc->hp), &MSO(pllc->p), lnk->pid));
-    if (lnk->type == LINK_NODE) {
-	targets = make_small(ERTS_LINK_REFC(lnk));
-    } else if (ERTS_LINK_ROOT(lnk) != NULL) {
-	old_res = pllc->res;
-	pllc->res = NIL;
-	erts_doforall_links(ERTS_LINK_ROOT(lnk),&do_make_one_lnk_element, vpllc);
-	targets = pllc->res;
-	pllc->res = old_res;
-    }
-    tup = TUPLE4(pllc->hp, pllc->tag, make_small(lnk->type), p, targets);
+    Eterm tup, t, pid, id;
+    ErtsLinkData *ldp = erts_link_to_data(lnk);
+
+    id = erts_bld_uword(&pllc->hp, NULL, (UWord) ldp);
+
+    if (is_immed(lnk->other.item))
+        pid = lnk->other.item;
+    else {
+        Uint sz = size_object(lnk->other.item);
+        pid = copy_struct(lnk->other.item, sz, &(pllc->hp), &MSO(pllc->p));
+    }
+
+    switch (lnk->type) {
+    case ERTS_LNK_TYPE_PROC:
+        t = am_process;
+        break;
+    case ERTS_LNK_TYPE_PORT:
+        t = am_port;
+        break;
+    case ERTS_LNK_TYPE_DIST_PROC: {
+        ERTS_DECL_AM(dist_process);
+        t = AM_dist_process;
+        break;
+    }
+    default:
+        ERTS_INTERNAL_ERROR("Unkown link type");
+        t = am_undefined;
+        break;
+    }
+
+    tup = TUPLE4(pllc->hp, pllc->tag, t, pid, id);
     pllc->hp += 5;
     pllc->res = CONS(pllc->hp, tup, pllc->res);
     pllc->hp += 2;
 }
 
 static Eterm 
-make_link_list(Process *p, ErtsLink *root, Eterm tail)
+make_link_list(Process *p, int tree, ErtsLink *root, Eterm tail)
 {
     DECL_AM(erl_link);
     Uint sz = 0;
     LnkListContext llc;
+    void (*foreach)(ErtsLink *,
+                    void (*)(ErtsLink *, void *),
+                    void *);
 
-    erts_doforall_links(root, &do_calc_lnk_size, &sz);
+    foreach = tree ? erts_link_tree_foreach : erts_link_list_foreach;
+
+    (*foreach)(root, calc_lnk_size, (void *) &sz);
     if (sz == 0) {
 	return tail;
     }
@@ -335,7 +427,7 @@ make_link_list(Process *p, ErtsLink *root, Eterm tail)
     llc.hp = HAlloc(p,sz);
     llc.res = tail;
     llc.tag = AM_erl_link;
-    erts_doforall_links(root, &do_make_one_lnk_element, &llc);
+    (*foreach)(root, make_one_lnk_element, (void *) &llc);
     return llc.res;
 }
 
@@ -381,6 +473,8 @@ typedef struct {
 	Eterm term;
 	ErtsResource* resource;
     }entity;
+    int named;
+    Uint16 type;
     Eterm node;
     /* pid is actual target being monitored, no matter pid/port or name */
     Eterm pid;
@@ -423,78 +517,103 @@ static void collect_one_link(ErtsLink *lnk, void *vmicp)
 {
     MonitorInfoCollection *micp = vmicp;
     EXTEND_MONITOR_INFOS(micp);
-    if (!(lnk->type == LINK_PID)) {
-	return;
-    }
-    micp->mi[micp->mi_i].entity.term = lnk->pid;
-    micp->sz += 2 + NC_HEAP_SIZE(lnk->pid);
+    micp->mi[micp->mi_i].entity.term = lnk->other.item;
+    micp->sz += 2 + NC_HEAP_SIZE(lnk->other.item);
     micp->mi_i++;
 } 
 
 static void collect_one_origin_monitor(ErtsMonitor *mon, void *vmicp)
 {
-    MonitorInfoCollection *micp = vmicp;
+    if (erts_monitor_is_origin(mon)) {
+        MonitorInfoCollection *micp = vmicp;
  
-    if (mon->type != MON_ORIGIN) {
-	return;
-    }
-    EXTEND_MONITOR_INFOS(micp);
-    if (is_atom(mon->u.pid)) { /* external by name */
-	micp->mi[micp->mi_i].entity.term = mon->name;
-        micp->mi[micp->mi_i].node = mon->u.pid;
-        micp->sz += 3; /* need one 2-tuple */
-    } else if (is_external_pid(mon->u.pid)) { /* external by pid */
-	micp->mi[micp->mi_i].entity.term = mon->u.pid;
-        micp->mi[micp->mi_i].node = NIL;
-        micp->sz += NC_HEAP_SIZE(mon->u.pid);
-    } else if (!is_nil(mon->name)) { /* internal by name */
-	micp->mi[micp->mi_i].entity.term = mon->name;
-        micp->mi[micp->mi_i].node = erts_this_dist_entry->sysname;
-        micp->sz += 3; /* need one 2-tuple */
-    } else { /* internal by pid */
-	micp->mi[micp->mi_i].entity.term = mon->u.pid;
-        micp->mi[micp->mi_i].node = NIL;
-	/* no additional heap space needed */
-    }
-
-    /* have always pid at hand, to assist with figuring out if its a port or
-     * a process, when we monitored by name and process_info is requested.
-     * See: erl_bif_info.c:process_info_aux section for am_monitors */
-    micp->mi[micp->mi_i].pid = mon->u.pid;
+        EXTEND_MONITOR_INFOS(micp);
+
+        micp->mi[micp->mi_i].type = mon->type;
+
+        switch (mon->type) {
+        case ERTS_MON_TYPE_PROC:
+        case ERTS_MON_TYPE_PORT:
+        case ERTS_MON_TYPE_DIST_PROC:
+        case ERTS_MON_TYPE_TIME_OFFSET:
+            if (!(mon->flags & ERTS_ML_FLG_NAME)) {
+                micp->mi[micp->mi_i].named = 0;
+                micp->mi[micp->mi_i].entity.term = mon->other.item;
+                micp->mi[micp->mi_i].node = NIL;
+                if (is_not_atom(mon->other.item))
+                    micp->sz += NC_HEAP_SIZE(mon->other.item);
+            }
+            else {
+                ErtsMonitorDataExtended *mdep;
+                micp->mi[micp->mi_i].named = !0;
+                mdep = (ErtsMonitorDataExtended *) erts_monitor_to_data(mon);
+                micp->mi[micp->mi_i].entity.term = mdep->u.name;
+                if (mdep->dist)
+                    micp->mi[micp->mi_i].node = mdep->dist->nodename;
+                else
+                    micp->mi[micp->mi_i].node = erts_this_dist_entry->sysname;
+                micp->sz += 3; /* need one 2-tuple */
+            }
 
-    micp->mi_i++;
-    micp->sz += 2 + 3; /* For a cons cell and a 2-tuple */
+            /* have always pid at hand, to assist with figuring out if its a port or
+             * a process, when we monitored by name and process_info is requested.
+             * See: erl_bif_info.c:process_info_aux section for am_monitors */
+            micp->mi[micp->mi_i].pid = mon->other.item;
+
+            micp->mi_i++;
+            micp->sz += 2 + 3; /* For a cons cell and a 2-tuple */
+            break;
+        default:
+            break;
+        }
+    }
 }
 
 static void collect_one_target_monitor(ErtsMonitor *mon, void *vmicp)
 {
     MonitorInfoCollection *micp = vmicp;
  
-    if (mon->type != MON_TARGET && mon->type != MON_NIF_TARGET) {
-        return;
-    }
+    if (erts_monitor_is_target(mon)) {
 
-    EXTEND_MONITOR_INFOS(micp);
+        EXTEND_MONITOR_INFOS(micp);
   
+        micp->mi[micp->mi_i].type = mon->type;
+        micp->mi[micp->mi_i].named = !!(mon->flags & ERTS_ML_FLG_NAME);
+        switch (mon->type) {
+
+        case ERTS_MON_TYPE_PROC:
+        case ERTS_MON_TYPE_PORT:
+        case ERTS_MON_TYPE_DIST_PROC:
+
+            micp->mi[micp->mi_i].entity.term = mon->other.item;
+            micp->mi[micp->mi_i].node = NIL;
+            micp->sz += NC_HEAP_SIZE(mon->other.item);
+
+            micp->sz += 2; /* cons */;
+            micp->mi_i++;
+            break;
+
+        case ERTS_MON_TYPE_RESOURCE:
+
+            micp->mi[micp->mi_i].entity.resource = mon->other.ptr;
+            micp->mi[micp->mi_i].node = NIL;
+            micp->sz += erts_resource_ref_size(mon->other.ptr);
+
+            micp->sz += 2; /* cons */;
+            micp->mi_i++;
+            break;
+
+        default:
+            break;
+        }
 
-    if (mon->type == MON_NIF_TARGET) {
-	micp->mi[micp->mi_i].entity.resource = mon->u.resource;
-        micp->mi[micp->mi_i].node = make_small(MON_NIF_TARGET);
-        micp->sz += erts_resource_ref_size(mon->u.resource);
-    }
-    else {
-	micp->mi[micp->mi_i].entity.term = mon->u.pid;
-        micp->mi[micp->mi_i].node = NIL;
-        micp->sz += NC_HEAP_SIZE(mon->u.pid);
     }
-    micp->sz += 2; /* cons */;
-    micp->mi_i++;
 }
 
 typedef struct {
     Process *c_p;
     ErtsProcLocks c_p_locks;
-    ErtsSuspendMonitor **smi;
+    ErtsMonitorSuspend **smi;
     Uint smi_i;
     Uint smi_max;
     int sz;
@@ -517,10 +636,10 @@ do {									\
 				       (SMICP)->smi,			\
 				       ((SMICP)->smi_max		\
 					+ ERTS_SMI_INC)			\
-				       * sizeof(ErtsSuspendMonitor *))	\
+				       * sizeof(ErtsMonitorSuspend *))	\
 			: erts_alloc(ERTS_ALC_T_TMP,			\
 				     ERTS_SMI_INC			\
-				     * sizeof(ErtsSuspendMonitor *)));	\
+				     * sizeof(ErtsMonitorSuspend *)));	\
 	(SMICP)->smi_max += ERTS_SMI_INC;				\
     }									\
  } while (0)
@@ -533,12 +652,13 @@ do {									\
  } while (0)
 
 static void
-collect_one_suspend_monitor(ErtsSuspendMonitor *smon, void *vsmicp)
+collect_one_suspend_monitor(ErtsMonitor *mon, void *vsmicp)
 {
+    ErtsMonitorSuspend *smon = erts_monitor_suspend(mon);
     ErtsSuspendMonitorInfoCollection *smicp = vsmicp;
     Process *suspendee = erts_pid2proc(smicp->c_p,
 				       smicp->c_p_locks,
-				       smon->pid,
+				       mon->other.item,
 				       0);
     if (suspendee) { /* suspendee is alive */
 	Sint a, p;
@@ -572,29 +692,23 @@ collect_one_suspend_monitor(ErtsSuspendMonitor *smon, void *vsmicp)
 
 #define ERTS_PI_FAIL_TYPE_BADARG		0
 #define ERTS_PI_FAIL_TYPE_YIELD			1
-#define ERTS_PI_FAIL_TYPE_AWAIT_EXIT		2
+#define ERTS_PI_FAIL_TYPE_EXITED                2
 
 static ERTS_INLINE ErtsProcLocks
 pi_locks(Eterm info)
 {
     switch (info) {
-    case am_status:
     case am_priority:
-    case am_trap_exit:
-	return ERTS_PROC_LOCK_STATUS;
-    case am_links:
-    case am_monitors:
-    case am_monitored_by:
-    case am_suspending:
-	return ERTS_PROC_LOCK_LINK;
+    case am_status:
+        return 0;
+    case am_suspended:
+        return ERTS_PROC_LOCK_STATUS;
     case am_messages:
     case am_message_queue_len:
     case am_total_heap_size:
-	return ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_MSGQ;
-    case am_memory:
-	return ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCK_MSGQ;
+        return ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_MSGQ;
     default:
-	return ERTS_PROC_LOCK_MAIN;
+        return ERTS_PROC_LOCK_MAIN;
     }
 }
 
@@ -742,7 +856,7 @@ process_info_init(void)
 }
 
 static ERTS_INLINE Process *
-pi_pid2proc(Process *c_p, Eterm pid, ErtsProcLocks info_locks)
+pi_lookup_proc(Process *c_p, Eterm pid, ErtsProcLocks *locks)
 {
     /*
      * If the main lock is needed, we use erts_pid2proc_not_running()
@@ -757,23 +871,79 @@ pi_pid2proc(Process *c_p, Eterm pid, ErtsProcLocks info_locks)
      * is currently running.
      */
 
-    if (info_locks & ERTS_PROC_LOCK_MAIN)
-	return erts_pid2proc_not_running(c_p, ERTS_PROC_LOCK_MAIN,
-					 pid, info_locks);
-    else
-	return erts_pid2proc(c_p, ERTS_PROC_LOCK_MAIN,
-			     pid, info_locks);
+    if ((*locks) & ERTS_PROC_LOCK_MAIN) {
+        erts_aint32_t state;
+        int local_only, done;
+        Process *rp;
+        ErtsProcLocks more_locks;
+
+        rp = erts_pid2proc_not_running(c_p, ERTS_PROC_LOCK_MAIN,
+                                       pid, ERTS_PROC_LOCK_MAIN);
+
+        if (!rp || rp == ERTS_PROC_LOCK_BUSY)
+            return rp;
+
+        if ((*locks) & ERTS_PROC_LOCK_MSGQ) {
+            /*
+             * Move in queue into private queue and
+             * release msgq lock, enabling others to
+             * send messages to the process while it
+             * is being inspected...
+             */
+            erts_proc_lock(rp, ERTS_PROC_LOCK_MSGQ);
+            erts_proc_sig_fetch(rp);
+            erts_proc_unlock(rp, ERTS_PROC_LOCK_MSGQ);
+            (*locks) &= ~ERTS_PROC_LOCK_MSGQ;
+	}
+
+        /*
+         * Handle all signals received up to this point
+         * in order to preserve signal order.
+         * 
+         * FIX ME: Should be done yielding...
+         */
+        local_only = 0;
+        do {
+            int r = CONTEXT_REDS;
+            done = erts_proc_sig_handle_incoming(rp, &state, &r,
+                                                 CONTEXT_REDS,
+                                                 local_only);
+            local_only = !0;
+            BUMP_REDS(c_p, r);
+        } while (!done && !(state & ERTS_PSFLG_EXITING));
+
+        if (state & ERTS_PSFLG_EXITING) {
+            if (rp != c_p)
+                erts_proc_unlock(rp, ERTS_PROC_LOCK_MAIN);
+            return NULL;
+        }
+        more_locks = (*locks) & ~ERTS_PROC_LOCK_MAIN;
+        if (more_locks)
+            erts_proc_lock(rp, more_locks);
+        return rp;
+    }
+
+    ASSERT(!((*locks) & ERTS_PROC_LOCK_MSGQ));
+
+    if (*locks)
+        return erts_pid2proc(c_p, ERTS_PROC_LOCK_MAIN,
+			     pid, *locks);
+
+    return erts_proc_lookup(pid);
 }
 
 
 
+
+
 static BIF_RETTYPE
 process_info_aux(Process *BIF_P,
 		 Process *rp,
 		 ErtsProcLocks rp_locks,
 		 Eterm rpid,
 		 Eterm item,
-		 int always_wrap);
+		 int always_wrap,
+                 int *reds);
 
 #define ERTS_PI_RES_ELEM_IX_BUF_INC 1024
 #define ERTS_PI_DEF_RES_ELEM_IX_BUF_SZ ERTS_PI_ARGS
@@ -793,6 +963,7 @@ process_info_list(Process *c_p, Eterm pid, Eterm list, int always_wrap,
     ErtsProcLocks locks = (ErtsProcLocks) 0;
     int res_len, ix;
     Process *rp = NULL;
+    int reds = 0;
 
     *fail_type = ERTS_PI_FAIL_TYPE_BADARG;
 
@@ -844,9 +1015,14 @@ process_info_list(Process *c_p, Eterm pid, Eterm list, int always_wrap,
 
     ASSERT(res_len > 0);
 
-    rp = pi_pid2proc(c_p, pid, locks|ERTS_PROC_LOCK_STATUS);
+    rp = pi_lookup_proc(c_p, pid, &locks);
     if (!rp) {
-	res = am_undefined;
+        if (c_p->common.id != pid)
+            res = am_undefined;
+        else {
+            *fail_type = ERTS_PI_FAIL_TYPE_EXITED;
+            res = THE_NON_VALUE;
+        }
 	goto done;
     }
     else if (rp == ERTS_PROC_LOCK_BUSY) {
@@ -855,38 +1031,9 @@ process_info_list(Process *c_p, Eterm pid, Eterm list, int always_wrap,
 	*fail_type = ERTS_PI_FAIL_TYPE_YIELD;
 	goto done;
     }
-    else if (c_p != rp && ERTS_PROC_PENDING_EXIT(rp)) {
-	locks |= ERTS_PROC_LOCK_STATUS;
-	res = THE_NON_VALUE;
-	*fail_type = ERTS_PI_FAIL_TYPE_AWAIT_EXIT;
-	goto done;
-    }
-    else {
-	ErtsProcLocks unlock_locks = 0;
-
-	if (c_p == rp)
-	    locks |= ERTS_PROC_LOCK_MAIN;
 
-	if (!(locks & ERTS_PROC_LOCK_STATUS))
-	    unlock_locks |= ERTS_PROC_LOCK_STATUS;
-
-	if (locks & ERTS_PROC_LOCK_MSGQ) {
-	    /*
-	     * Move in queue into private queue and
-	     * release msgq lock, enabling others to
-	     * send messages to the process while it
-	     * is being inspected...
-	     */
-	    ASSERT(locks & ERTS_PROC_LOCK_MAIN);
-	    ERTS_MSGQ_MV_INQ2PRIVQ(rp);
-	    locks &= ~ERTS_PROC_LOCK_MSGQ;
-	    unlock_locks |= ERTS_PROC_LOCK_MSGQ;
-	}
-
-	if (unlock_locks)
-	    erts_proc_unlock(rp, unlock_locks);
-
-    }
+    if (c_p == rp)
+        locks |= ERTS_PROC_LOCK_MAIN;
 
     /*
      * We always handle 'messages' first if it should be part
@@ -898,16 +1045,23 @@ process_info_list(Process *c_p, Eterm pid, Eterm list, int always_wrap,
     if (want_messages) {
 	ix = pi_arg2ix(am_messages);
 	ASSERT(part_res[ix] == THE_NON_VALUE);
-	part_res[ix] = process_info_aux(c_p, rp, locks, pid, am_messages, always_wrap);
-	ASSERT(part_res[ix] != THE_NON_VALUE);
+	res = process_info_aux(c_p, rp, locks, pid, am_messages,
+                               always_wrap, &reds);
+	ASSERT(res != am_undefined);
+	ASSERT(res != THE_NON_VALUE);
+        part_res[ix] = res;
     }
 
     for (; res_elem_ix_ix >= 0; res_elem_ix_ix--) {
 	ix = res_elem_ix[res_elem_ix_ix];
 	if (part_res[ix] == THE_NON_VALUE) {
 	    arg = pi_ix2arg(ix);
-	    part_res[ix] = process_info_aux(c_p, rp, locks, pid, arg, always_wrap);
-	    ASSERT(part_res[ix] != THE_NON_VALUE);
+	    res = process_info_aux(c_p, rp, locks, pid, arg,
+                                   always_wrap, &reds);
+            if (res == am_undefined)
+                goto done;
+	    ASSERT(res != THE_NON_VALUE);
+            part_res[ix] = res;
 	}
     }
 
@@ -947,6 +1101,8 @@ process_info_list(Process *c_p, Eterm pid, Eterm list, int always_wrap,
     if (res_elem_ix != &def_res_elem_ix_buf[0])
 	erts_free(ERTS_ALC_T_TMP, res_elem_ix);
 
+    BUMP_REDS(c_p, reds);
+
     return res;
 }
 
@@ -970,8 +1126,8 @@ BIF_RETTYPE process_info_1(BIF_ALIST_1)
 	    BIF_ERROR(BIF_P, BADARG);
 	case ERTS_PI_FAIL_TYPE_YIELD:
 	    ERTS_BIF_YIELD1(bif_export[BIF_process_info_1], BIF_P, BIF_ARG_1);
-	case ERTS_PI_FAIL_TYPE_AWAIT_EXIT:
-	    ERTS_BIF_AWAIT_X_DATA_TRAP(BIF_P, BIF_ARG_1, am_undefined);
+        case ERTS_PI_FAIL_TYPE_EXITED:
+            ERTS_BIF_EXITED(BIF_P);
 	default:
 	    erts_exit(ERTS_ABORT_EXIT, "%s:%d: Internal error", __FILE__, __LINE__);
 	}
@@ -988,7 +1144,7 @@ BIF_RETTYPE process_info_2(BIF_ALIST_2)
     Process *rp;
     Eterm pid = BIF_ARG_1;
     ErtsProcLocks info_locks;
-    int fail_type;
+    int fail_type, reds = 0;
 
     if (is_external_pid(pid)
 	&& external_pid_dist_entry(pid) == erts_this_dist_entry)
@@ -1010,8 +1166,8 @@ BIF_RETTYPE process_info_2(BIF_ALIST_2)
 	    case ERTS_PI_FAIL_TYPE_YIELD:
 		ERTS_BIF_YIELD2(bif_export[BIF_process_info_2], BIF_P,
 				BIF_ARG_1, BIF_ARG_2);
-	    case ERTS_PI_FAIL_TYPE_AWAIT_EXIT:
-		ERTS_BIF_AWAIT_X_DATA_TRAP(BIF_P, BIF_ARG_1, am_undefined);
+            case ERTS_PI_FAIL_TYPE_EXITED:
+                ERTS_BIF_EXITED(BIF_P);
 	    default:
 		erts_exit(ERTS_ABORT_EXIT, "%s:%d: Internal error",
 			 __FILE__, __LINE__);
@@ -1026,44 +1182,23 @@ BIF_RETTYPE process_info_2(BIF_ALIST_2)
 
     info_locks = pi_locks(BIF_ARG_2); 
 
-    rp = pi_pid2proc(BIF_P, pid, info_locks|ERTS_PROC_LOCK_STATUS);
-    if (!rp)
-	res = am_undefined;
+    rp = pi_lookup_proc(BIF_P, pid, &info_locks);
+    if (!rp) {
+        if (BIF_P->common.id == pid)
+            ERTS_BIF_EXITED(BIF_P);
+	BIF_RET(am_undefined);
+    }
     else if (rp == ERTS_PROC_LOCK_BUSY)
 	ERTS_BIF_YIELD2(bif_export[BIF_process_info_2], BIF_P,
 			BIF_ARG_1, BIF_ARG_2);
-    else if (rp != BIF_P && ERTS_PROC_PENDING_EXIT(rp)) {
-	erts_proc_unlock(rp, info_locks|ERTS_PROC_LOCK_STATUS);
-	ERTS_BIF_AWAIT_X_DATA_TRAP(BIF_P, BIF_ARG_1, am_undefined);
-    }
-    else {
-	ErtsProcLocks unlock_locks = 0;
-
-	if (BIF_P == rp)
-	    info_locks |= ERTS_PROC_LOCK_MAIN;
 
-	if (!(info_locks & ERTS_PROC_LOCK_STATUS))
-	    unlock_locks |= ERTS_PROC_LOCK_STATUS;
-
-	if (info_locks & ERTS_PROC_LOCK_MSGQ) {
-	    /*
-	     * Move in queue into private queue and
-	     * release msgq lock, enabling others to
-	     * send messages to the process while it
-	     * is being inspected...
-	     */
-	    ASSERT(info_locks & ERTS_PROC_LOCK_MAIN);
-	    ERTS_MSGQ_MV_INQ2PRIVQ(rp);
-	    info_locks &= ~ERTS_PROC_LOCK_MSGQ;
-	    unlock_locks |= ERTS_PROC_LOCK_MSGQ;
-	}
+    if (BIF_P == rp)
+        info_locks |= ERTS_PROC_LOCK_MAIN;
 
-	if (unlock_locks)
-	    erts_proc_unlock(rp, unlock_locks);
+    res = process_info_aux(BIF_P, rp, info_locks, pid, BIF_ARG_2,
+                           0, &reds);
 
-	res = process_info_aux(BIF_P, rp, info_locks, pid, BIF_ARG_2, 0);
-    }
-    ASSERT(is_value(res));
+    BUMP_REDS(BIF_P, reds);
 
     if (BIF_P == rp)
 	info_locks &= ~ERTS_PROC_LOCK_MAIN;
@@ -1080,11 +1215,14 @@ process_info_aux(Process *BIF_P,
 		 ErtsProcLocks rp_locks,
 		 Eterm rpid,
 		 Eterm item,
-		 int always_wrap)
+		 int always_wrap,
+                 int *reds)
 {
     Eterm *hp;
     Eterm res = NIL;
 
+    (*reds)++;
+
     ASSERT(rp);
 
     /*
@@ -1143,14 +1281,15 @@ process_info_aux(Process *BIF_P,
 	break;
 
     case am_status:
-	res = erts_process_status(rp, rpid);
-	ASSERT(res != am_undefined);
+        res = erts_process_state2status(erts_atomic32_read_nob(&rp->state));
+        if (res == am_exiting || res == am_free)
+            return am_undefined;
 	hp = HAlloc(BIF_P, 3);
 	break;
 
     case am_messages: {
 
-	if (rp->msg.len == 0 || ERTS_TRACE_FLAGS(rp) & F_SENSITIVE) {
+	if (rp->sig_qs.len == 0 || ERTS_TRACE_FLAGS(rp) & F_SENSITIVE) {
 	    hp = HAlloc(BIF_P, 3);
 	} else {
 	    ErtsMessageInfo *mip;
@@ -1161,16 +1300,17 @@ process_info_aux(Process *BIF_P,
 #endif
 
 	    mip = erts_alloc(ERTS_ALC_T_TMP,
-			     rp->msg.len*sizeof(ErtsMessageInfo));
+			     rp->sig_qs.len*sizeof(ErtsMessageInfo));
 
 	    /*
 	     * Note that message queue may shrink when calling
-	     * erts_prep_msgq_for_inspection() since it removes
+	     * erts_proc_sig_prep_msgq_for_inspection() since it removes
 	     * corrupt distribution messages.
 	     */
-	    heap_need = erts_prep_msgq_for_inspection(BIF_P, rp, rp_locks, mip);
+	    heap_need = erts_proc_sig_prep_msgq_for_inspection(BIF_P, rp,
+                                                               rp_locks, mip);
 	    heap_need += 3; /* top 2-tuple */
-	    heap_need += rp->msg.len*2; /* Cons cells */
+	    heap_need += rp->sig_qs.len*2; /* Cons cells */
 
 	    hp = HAlloc(BIF_P, heap_need); /* heap_need is exact */
 #ifdef DEBUG
@@ -1178,7 +1318,7 @@ process_info_aux(Process *BIF_P,
 #endif
 
 	    /* Build list of messages... */
-	    for (i = rp->msg.len - 1, res = NIL; i >= 0; i--) {
+	    for (i = rp->sig_qs.len - 1, res = NIL; i >= 0; i--) {
 		Eterm msg = ERL_MESSAGE_TERM(mip[i].msgp);
 		Uint sz = mip[i].size;
 
@@ -1191,6 +1331,11 @@ process_info_aux(Process *BIF_P,
 
 	    ASSERT(hp_end == hp + 3);
 
+            if (rp->sig_qs.len > CONTEXT_REDS*4)
+                *reds += CONTEXT_REDS*4;
+            else
+                *reds += rp->sig_qs.len / 4;
+
 	    erts_free(ERTS_ALC_T_TMP, mip);
 	}
 	break;
@@ -1198,7 +1343,7 @@ process_info_aux(Process *BIF_P,
 
     case am_message_queue_len:
 	hp = HAlloc(BIF_P, 3);
-	res = make_small(rp->msg.len);
+	res = make_small(rp->sig_qs.len);
 	break;
 
     case am_links: {
@@ -1208,7 +1353,7 @@ process_info_aux(Process *BIF_P,
 
 	INIT_MONITOR_INFOS(mic);
 
-	erts_doforall_links(ERTS_P_LINKS(rp),&collect_one_link,&mic);
+	erts_link_tree_foreach(ERTS_P_LINKS(rp), collect_one_link, (void *) &mic);
 
 	hp = HAlloc(BIF_P, 3 + mic.sz);
 	res = NIL;
@@ -1217,6 +1362,12 @@ process_info_aux(Process *BIF_P,
 	    res = CONS(hp, item, res);
 	    hp += 2;
 	}
+
+        if (mic.mi_i > CONTEXT_REDS*4)
+            *reds += CONTEXT_REDS*4;
+        else
+            *reds += mic.mi_i / 4;
+
 	DESTROY_MONITOR_INFOS(mic);
 	break;
     }
@@ -1226,12 +1377,14 @@ process_info_aux(Process *BIF_P,
         int i;
 
 	INIT_MONITOR_INFOS(mic);
-        erts_doforall_monitors(ERTS_P_MONITORS(rp),
-                               &collect_one_origin_monitor, &mic);
+        erts_monitor_tree_foreach(ERTS_P_MONITORS(rp),
+                                  collect_one_origin_monitor,
+                                  (void *) &mic);
+
         hp = HAlloc(BIF_P, 3 + mic.sz);
 	res = NIL;
 	for (i = 0; i < mic.mi_i; i++) {
-	    if (is_atom(mic.mi[i].entity.term)) {
+	    if (mic.mi[i].named) {
 		/* Monitor by name. 
                  * Build {process|port, {Name, Node}} and cons it.
 		 */
@@ -1251,11 +1404,28 @@ process_info_aux(Process *BIF_P,
                 hp += 2;
 	    }
 	    else {
-                /* Monitor by pid. Build {process|port, Pid} and cons it. */
+                /* Build {process|port|time_offset, Pid|clock_service} and cons it. */
 		Eterm t;
-		Eterm pid = STORE_NC(&hp, &MSO(BIF_P), mic.mi[i].entity.term);
+		Eterm pid;
+                Eterm m_type;
+
+                if (is_atom(mic.mi[i].entity.term))
+                    pid = mic.mi[i].entity.term;
+                else
+                    pid = STORE_NC(&hp, &MSO(BIF_P), mic.mi[i].entity.term);
+
+                switch (mic.mi[i].type) {
+                case ERTS_MON_TYPE_PORT:
+                    m_type = am_port;
+                    break;
+                case ERTS_MON_TYPE_TIME_OFFSET:
+                    m_type = am_time_offset;
+                    break;
+                default:
+                    m_type = am_process;
+                    break;
+                }
 
-                Eterm m_type = is_port(mic.mi[i].pid) ? am_port : am_process;
                 ASSERT(is_pid(mic.mi[i].pid)
                     || is_port(mic.mi[i].pid));
 
@@ -1265,6 +1435,12 @@ process_info_aux(Process *BIF_P,
                 hp += 2;
 	    }
 	}
+
+        if (mic.mi_i > CONTEXT_REDS*4)
+            *reds += CONTEXT_REDS*4;
+        else
+            *reds += mic.mi_i / 4;
+
         DESTROY_MONITOR_INFOS(mic);
 	break;
     }
@@ -1275,20 +1451,34 @@ process_info_aux(Process *BIF_P,
 	Eterm item;
 
 	INIT_MONITOR_INFOS(mic);
-	erts_doforall_monitors(ERTS_P_MONITORS(rp),&collect_one_target_monitor,&mic);
+        erts_monitor_list_foreach(ERTS_P_LT_MONITORS(rp),
+                                  collect_one_target_monitor,
+                                  (void *) &mic);
+        erts_monitor_tree_foreach(ERTS_P_MONITORS(rp),
+                                  collect_one_target_monitor,
+                                  (void *) &mic);
+
 	hp = HAlloc(BIF_P, 3 + mic.sz);
 
 	res = NIL;
 	for (i = 0; i < mic.mi_i; ++i) {
-            if (mic.mi[i].node == make_small(MON_NIF_TARGET)) {
-                item = erts_bld_resource_ref(&hp, &MSO(BIF_P), mic.mi[i].entity.resource);
-            }
-            else {
-                item = STORE_NC(&hp, &MSO(BIF_P), mic.mi[i].entity.term);
-            }
+            if (mic.mi[i].type == ERTS_MON_TYPE_RESOURCE)
+                item = erts_bld_resource_ref(&hp,
+                                             &MSO(BIF_P),
+                                             mic.mi[i].entity.resource);
+            else
+                item = STORE_NC(&hp,
+                                &MSO(BIF_P),
+                                mic.mi[i].entity.term);
 	    res = CONS(hp, item, res);
 	    hp += 2;
 	}
+
+        if (mic.mi_i > CONTEXT_REDS*4)
+            *reds += CONTEXT_REDS*4;
+        else
+            *reds += mic.mi_i / 4;
+
 	DESTROY_MONITOR_INFOS(mic);
 	break;
     }
@@ -1305,11 +1495,11 @@ process_info_aux(Process *BIF_P,
 					BIF_P,
 					(BIF_P == rp
 					 ? ERTS_PROC_LOCK_MAIN
-					 : 0) | ERTS_PROC_LOCK_LINK);
+					 : 0) | ERTS_PROC_LOCK_STATUS);
 
-	erts_doforall_suspend_monitors(rp->suspend_monitors,
-				       &collect_one_suspend_monitor,
-				       &smic);
+	erts_monitor_tree_foreach(rp->suspend_monitors,
+                                  &collect_one_suspend_monitor,
+                                  &smic);
 	hp = HAlloc(BIF_P, 3 + smic.sz);
 #ifdef DEBUG
 	hp_end = hp + smic.sz;
@@ -1333,12 +1523,17 @@ process_info_aux(Process *BIF_P,
 		pending = small_to_big(p, hp);
 		hp += BIG_UINT_HEAP_SIZE;
 	    }
-	    item = TUPLE3(hp, smic.smi[i]->pid, active, pending);
+	    item = TUPLE3(hp, smic.smi[i]->mon.other.item, active, pending);
 	    hp += 4;
 	    res = CONS(hp, item, res);
 	    hp += 2;
 	}
 
+        if (smic.smi_i > CONTEXT_REDS*4)
+            *reds += CONTEXT_REDS*4;
+        else
+            *reds += smic.smi_i / 4;
+
 	ERTS_DESTROY_SUSPEND_MONITOR_INFOS(smic);
 	ASSERT(hp == hp_end);
 
@@ -1346,18 +1541,22 @@ process_info_aux(Process *BIF_P,
     }
 
     case am_dictionary:
-	if (ERTS_TRACE_FLAGS(rp) & F_SENSITIVE) {
+	if (!rp->dictionary || (ERTS_TRACE_FLAGS(rp) & F_SENSITIVE)) {
 	    res = NIL;
 	} else {
+            Uint num = rp->dictionary->numElements;
 	    res = erts_dictionary_copy(BIF_P, rp->dictionary);
+            if (num > CONTEXT_REDS*4)
+                *reds += CONTEXT_REDS*4;
+            else
+                *reds += (int) num / 4;
 	}
 	hp = HAlloc(BIF_P, 3);
 	break;
 
     case am_trap_exit: {
-	erts_aint32_t state = erts_atomic32_read_nob(&rp->state);
 	hp = HAlloc(BIF_P, 3);
-	if (state & ERTS_PSFLG_TRAP_EXIT)
+        if (rp->flags & F_TRAP_EXIT)
 	    res = am_true;
 	else
 	    res = am_false;
@@ -1414,7 +1613,6 @@ process_info_aux(Process *BIF_P,
     }
 
     case am_total_heap_size: {
-	ErtsMessage *mp;
 	Uint total_heap_size;
 	Uint hsz = 3;
 
@@ -1424,10 +1622,19 @@ process_info_aux(Process *BIF_P,
 
 	total_heap_size += rp->mbuf_sz;
 
-        if (rp->flags & F_ON_HEAP_MSGQ)
-            for (mp = rp->msg.first; mp; mp = mp->next)
-                if (mp->data.attached)
-                    total_heap_size += erts_msg_attached_data_size(mp);
+        if (rp->flags & F_ON_HEAP_MSGQ) {
+            ERTS_FOREACH_SIG_PRIVQS(
+                rp, mp,
+                {
+                    if (ERTS_SIG_IS_MSG(mp) && mp->data.attached)
+                        total_heap_size += erts_msg_attached_data_size(mp);
+                });
+
+            if (rp->sig_qs.len > CONTEXT_REDS*4)
+                *reds += CONTEXT_REDS*4;
+            else
+                *reds += rp->sig_qs.len / 4;
+        }
 
 	(void) erts_bld_uint(NULL, &hsz, total_heap_size);
 	hp = HAlloc(BIF_P, hsz);
@@ -1450,6 +1657,12 @@ process_info_aux(Process *BIF_P,
 	(void) erts_bld_uint(NULL, &hsz, size);
 	hp = HAlloc(BIF_P, hsz);
 	res = erts_bld_uint(&hp, NULL, size);
+
+        if (rp->sig_qs.len > CONTEXT_REDS*4)
+            *reds += CONTEXT_REDS*4;
+        else
+            *reds += rp->sig_qs.len / 4;
+
 	break;
     }
 
@@ -1522,10 +1735,14 @@ process_info_aux(Process *BIF_P,
 	break;
     }
 
-    case am_priority:
+    case am_priority: {
+        erts_aint32_t state = erts_atomic32_read_nob(&rp->state);
+        if (ERTS_PSFLG_EXITING & state)
+            return am_undefined;
 	hp = HAlloc(BIF_P, 3);
-	res = erts_get_process_priority(rp);
+	res = erts_get_process_priority(state);
 	break;
+    }
 
     case am_trace:
 	hp = HAlloc(BIF_P, 3);
@@ -1628,6 +1845,8 @@ process_info_aux(Process *BIF_P,
 	(void) bld_magic_ref_bin_list(NULL, &sz, &MSO(rp));
 	hp = HAlloc(BIF_P, sz);
 	res = bld_magic_ref_bin_list(&hp, NULL, &MSO(rp));
+
+        *reds += 10;
 	break;
     }
 
@@ -2862,6 +3081,16 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
     BIF_ERROR(BIF_P, BADARG);
 }
 
+static void monitor_size(ErtsMonitor *mon, void *vsz)
+{
+    *((Uint *) vsz) = erts_monitor_size(mon);
+}
+
+static void link_size(ErtsMonitor *lnk, void *vsz)
+{
+    *((Uint *) vsz) = erts_link_size(lnk);
+}
+
 /**********************************************************************/ 
 /* Return information on ports */
 /* Info:
@@ -2897,7 +3126,7 @@ erts_bld_port_info(Eterm **hpp, ErlOffHeap *ohp, Uint *szp, Port *prt,
 
 	INIT_MONITOR_INFOS(mic);
 
-	erts_doforall_links(ERTS_P_LINKS(prt), &collect_one_link, &mic);
+	erts_link_tree_foreach(ERTS_P_LINKS(prt), collect_one_link, (void *) &mic);
 
 	if (szp)
 	    *szp += mic.sz;
@@ -2921,11 +3150,11 @@ erts_bld_port_info(Eterm **hpp, ErlOffHeap *ohp, Uint *szp, Port *prt,
     else if (item == am_monitors) {
 	MonitorInfoCollection mic;
 	int i;
-	Eterm item;
 
 	INIT_MONITOR_INFOS(mic);
-        erts_doforall_monitors(ERTS_P_MONITORS(prt),
-                               &collect_one_origin_monitor, &mic);
+        erts_monitor_tree_foreach(ERTS_P_MONITORS(prt),
+                                  collect_one_origin_monitor,
+                                  (void *) &mic);
 
 	if (szp)
 	    *szp += mic.sz;
@@ -2934,11 +3163,10 @@ erts_bld_port_info(Eterm **hpp, ErlOffHeap *ohp, Uint *szp, Port *prt,
 	    res = NIL;
 	    for (i = 0; i < mic.mi_i; i++) {
 		Eterm t;
-                Eterm m_type;
 
-                item = STORE_NC(hpp, ohp, mic.mi[i].entity.term);
-                m_type = is_port(item) ? am_port : am_process;
-                t = TUPLE2(*hpp, m_type, item);
+                ASSERT(mic.mi[i].type == ERTS_MON_TYPE_PORT);
+                ASSERT(is_internal_pid(mic.mi[i].entity.term));
+                t = TUPLE2(*hpp, am_process, mic.mi[i].entity.term);
 		*hpp += 3;
 		res = CONS(*hpp, t, res);
 		*hpp += 2;
@@ -2957,15 +3185,19 @@ erts_bld_port_info(Eterm **hpp, ErlOffHeap *ohp, Uint *szp, Port *prt,
         Eterm item;
 
         INIT_MONITOR_INFOS(mic);
-        erts_doforall_monitors(ERTS_P_MONITORS(prt),
-                               &collect_one_target_monitor, &mic);
+        erts_monitor_list_foreach(ERTS_P_LT_MONITORS(prt),
+                                  collect_one_target_monitor,
+                                  (void *) &mic);
+        erts_monitor_tree_foreach(ERTS_P_MONITORS(prt),
+                                  collect_one_target_monitor,
+                                  (void *) &mic);
         if (szp)
             *szp += mic.sz;
 
         if (hpp) {
             res = NIL;
             for (i = 0; i < mic.mi_i; ++i) {
-                ASSERT(mic.mi[i].node == NIL);
+                ASSERT(mic.mi[i].type != ERTS_MON_TYPE_RESOURCE);
                 item = STORE_NC(hpp, ohp, mic.mi[i].entity.term);
                 res = CONS(*hpp, item, res);
                 *hpp += 2;
@@ -3042,7 +3274,12 @@ erts_bld_port_info(Eterm **hpp, ErlOffHeap *ohp, Uint *szp, Port *prt,
 	 */
 	Uint size = 0;
 
-	erts_doforall_links(ERTS_P_LINKS(prt), &erts_one_link_size, &size);
+        erts_link_tree_foreach(ERTS_P_LINKS(prt),
+                               link_size, (void *) &size);
+        erts_monitor_tree_foreach(ERTS_P_MONITORS(prt),
+                                  monitor_size, (void *) &size);
+        erts_monitor_list_foreach(ERTS_P_LT_MONITORS(prt),
+                                  monitor_size, (void *) &size);
 
 	size += erts_port_data_size(prt);
 
@@ -3277,8 +3514,7 @@ BIF_RETTYPE is_process_alive_1(BIF_ALIST_1)
 	   BIF_RET(am_false);
        }
        else {
-	   if (erts_atomic32_read_acqb(&rp->state)
-		 & (ERTS_PSFLG_PENDING_EXIT|ERTS_PSFLG_EXITING))
+	   if (erts_atomic32_read_acqb(&rp->state) & ERTS_PSFLG_EXITING)
 	       ERTS_BIF_AWAIT_X_DATA_TRAP(BIF_P, BIF_ARG_1, am_false);
 	   else
 	       BIF_RET(am_true);
@@ -3310,16 +3546,6 @@ BIF_RETTYPE process_display_2(BIF_ALIST_2)
    if (rp == ERTS_PROC_LOCK_BUSY)
        ERTS_BIF_YIELD2(bif_export[BIF_process_display_2], BIF_P,
 		       BIF_ARG_1, BIF_ARG_2);
-   if (rp != BIF_P && ERTS_PROC_PENDING_EXIT(rp)) {
-       Eterm args[2] = {BIF_ARG_1, BIF_ARG_2};
-       erts_proc_unlock(rp, ERTS_PROC_LOCKS_ALL);
-       ERTS_BIF_AWAIT_X_APPLY_TRAP(BIF_P,
-				   BIF_ARG_1,
-				   am_erlang,
-				   am_process_display,
-				   args,
-				   2);
-   }
    erts_stack_dump(ERTS_PRINT_STDERR, NULL, rp);
    erts_proc_unlock(rp, (BIF_P == rp
 			     ? ERTS_PROC_LOCKS_ALL_MINOR
@@ -3692,22 +3918,59 @@ BIF_RETTYPE erts_debug_get_internal_state_1(BIF_ALIST_1)
 		    BIF_RET(erts_process_status(NULL, tp[2]));
 		}
 	    }
+            else if (ERTS_IS_ATOM_STR("connection_id", tp[1])) {
+                DistEntry *dep;
+                Eterm *hp, res;
+                Uint con_id, hsz = 0;
+                if (!is_atom(tp[2]))
+                    BIF_ERROR(BIF_P, BADARG);
+                dep = erts_sysname_to_connected_dist_entry(tp[2]);
+                if (!dep)
+                    BIF_ERROR(BIF_P, BADARG);
+                erts_de_rlock(dep);
+                con_id = (Uint) dep->connection_id;
+                erts_de_runlock(dep);
+                (void) erts_bld_uint(NULL, &hsz, con_id);
+                hp = hsz ? HAlloc(BIF_P, hsz) : NULL;
+                res = erts_bld_uint(&hp, NULL, con_id);
+                BIF_RET(res);
+            }
 	    else if (ERTS_IS_ATOM_STR("link_list", tp[1])) {
 		/* Used by erl_link_SUITE (emulator) */
 		if(is_internal_pid(tp[2])) {
+                    erts_aint32_t state;
 		    Eterm res;
 		    Process *p;
+                    int sigs_done, local_only;
 
 		    p = erts_pid2proc(BIF_P,
 				      ERTS_PROC_LOCK_MAIN,
 				      tp[2],
-				      ERTS_PROC_LOCK_LINK);
+				      ERTS_PROC_LOCK_MAIN);
 		    if (!p) {
 			ERTS_ASSERT_IS_NOT_EXITING(BIF_P);
 			BIF_RET(am_undefined);
 		    }
-		    res = make_link_list(BIF_P, ERTS_P_LINKS(p), NIL);
-		    erts_proc_unlock(p, ERTS_PROC_LOCK_LINK);
+                    
+                    local_only = 0;
+                    do {
+                        int reds = CONTEXT_REDS;
+                        sigs_done = erts_proc_sig_handle_incoming(p,
+                                                                  &state,
+                                                                  &reds,
+                                                                  CONTEXT_REDS,
+                                                                  local_only);
+                        local_only = !0;
+                    } while (!sigs_done && !(state & ERTS_PSFLG_EXITING));
+
+                    if (!(state & ERTS_PSFLG_EXITING))
+                        res = make_link_list(BIF_P, 1, ERTS_P_LINKS(p), NIL);
+                    else if (BIF_P == p)
+                        ERTS_BIF_EXITED(BIF_P);
+                    else
+                        res = am_undefined;
+                    if (BIF_P != p)
+                        erts_proc_unlock(p, ERTS_PROC_LOCK_MAIN);
 		    BIF_RET(res);
 		}
 		else if(is_internal_port(tp[2])) {
@@ -3718,19 +3981,20 @@ BIF_RETTYPE erts_debug_get_internal_state_1(BIF_ALIST_1)
 						 ERTS_PORT_SFLGS_INVALID_LOOKUP);
 		    if(!p)
 			BIF_RET(am_undefined);
-		    res = make_link_list(BIF_P, ERTS_P_LINKS(p), NIL);
+		    res = make_link_list(BIF_P, 1, ERTS_P_LINKS(p), NIL);
 		    erts_port_release(p);
 		    BIF_RET(res);
 		}
 		else if(is_node_name_atom(tp[2])) {
 		    DistEntry *dep = erts_find_dist_entry(tp[2]);
 		    if(dep) {
-			Eterm subres;
-			erts_de_links_lock(dep);
-			subres = make_link_list(BIF_P, dep->nlinks, NIL);
-			subres = make_link_list(BIF_P, dep->node_links, subres);
-			erts_de_links_unlock(dep);
-			BIF_RET(subres);
+			Eterm res = NIL;
+                        if (dep->mld) {
+                            erts_mtx_lock(&dep->mld->mtx);
+                            res = make_link_list(BIF_P, 0, dep->mld->links, NIL);
+                            erts_mtx_unlock(&dep->mld->mtx);
+                        }
+			BIF_RET(res);
 		    } else {
 			BIF_RET(am_undefined);
 		    }
@@ -3739,27 +4003,54 @@ BIF_RETTYPE erts_debug_get_internal_state_1(BIF_ALIST_1)
 	    else if (ERTS_IS_ATOM_STR("monitor_list", tp[1])) {
 		/* Used by erl_link_SUITE (emulator) */
 		if(is_internal_pid(tp[2])) {
+                    erts_aint32_t state;
 		    Process *p;
 		    Eterm res;
+                    int sigs_done, local_only;
 
 		    p = erts_pid2proc(BIF_P,
 				      ERTS_PROC_LOCK_MAIN,
 				      tp[2],
-				      ERTS_PROC_LOCK_LINK);
+				      ERTS_PROC_LOCK_MAIN);
 		    if (!p) {
 			ERTS_ASSERT_IS_NOT_EXITING(BIF_P);
 			BIF_RET(am_undefined);
 		    }
-		    res = make_monitor_list(BIF_P, ERTS_P_MONITORS(p));
-		    erts_proc_unlock(p, ERTS_PROC_LOCK_LINK);
+                    
+                    local_only = 0;
+                    do {
+                        int reds = CONTEXT_REDS;
+                        sigs_done = erts_proc_sig_handle_incoming(p,
+                                                                  &state,
+                                                                  &reds,
+                                                                  CONTEXT_REDS,
+                                                                  local_only);
+                        local_only = !0;
+                    } while (!sigs_done && !(state & ERTS_PSFLG_EXITING));
+
+                    if (!(state & ERTS_PSFLG_EXITING)) {
+                        res = make_monitor_list(BIF_P, 1, ERTS_P_MONITORS(p), NIL);
+                        res = make_monitor_list(BIF_P, 0, ERTS_P_LT_MONITORS(p), res);
+                    }
+                    else {
+                        if (BIF_P == p)
+                            ERTS_BIF_EXITED(BIF_P);
+                        else
+                            res = am_undefined;
+                    }
+                    if (BIF_P != p)
+                        erts_proc_unlock(p, ERTS_PROC_LOCK_MAIN);
 		    BIF_RET(res);
 		} else if(is_node_name_atom(tp[2])) {
 		    DistEntry *dep = erts_find_dist_entry(tp[2]);
 		    if(dep) {
-			Eterm ml;
-			erts_de_links_lock(dep);
-			ml = make_monitor_list(BIF_P, dep->monitors);
-			erts_de_links_unlock(dep);
+			Eterm ml = NIL;
+                        if (dep->mld) {
+                            erts_mtx_lock(&dep->mld->mtx);
+                            ml = make_monitor_list(BIF_P, 1, dep->mld->orig_name_monitors, NIL);
+                            ml = make_monitor_list(BIF_P, 0, dep->mld->monitors, ml);
+                            erts_mtx_unlock(&dep->mld->mtx);
+                        }
 			BIF_RET(ml);
 		    } else {
 			BIF_RET(am_undefined);
@@ -3777,18 +4068,6 @@ BIF_RETTYPE erts_debug_get_internal_state_1(BIF_ALIST_1)
 		}
 		BIF_RET(res);
 	    }
-	    else if (ERTS_IS_ATOM_STR("have_pending_exit", tp[1])) {
-		Process *rp = erts_pid2proc(BIF_P, ERTS_PROC_LOCK_MAIN,
-					    tp[2], ERTS_PROC_LOCK_STATUS);
-		if (!rp) {
-		    BIF_RET(am_undefined);
-		}
-		else {
-		    Eterm res = ERTS_PROC_PENDING_EXIT(rp) ? am_true : am_false;
-		    erts_proc_unlock(rp, ERTS_PROC_LOCK_STATUS);
-		    BIF_RET(res);
-		}
-	    }
 	    else if (ERTS_IS_ATOM_STR("binary_info", tp[1])) {
 		Eterm bin = tp[2];
 		if (is_binary(bin)) {
@@ -4115,57 +4394,6 @@ BIF_RETTYPE erts_debug_set_internal_state_2(BIF_ALIST_2)
 	    erts_set_gc_state(BIF_P, enable);
 	    BIF_RET(res);
 	}
-	else if (ERTS_IS_ATOM_STR("send_fake_exit_signal", BIF_ARG_1)) {
-	    /* Used by signal_SUITE (emulator) */
-
-	    /* Testcases depend on the exit being received via
-	       a pending exit when the receiver is the same as
-	       the caller.  */
-	    if (is_tuple(BIF_ARG_2)) {
-		Eterm* tp = tuple_val(BIF_ARG_2);
-		if (arityval(tp[0]) == 3
-		    && (is_pid(tp[1]) || is_port(tp[1]))
-		    && is_internal_pid(tp[2])) {
-		    int xres;
-		    ErtsProcLocks rp_locks = ERTS_PROC_LOCKS_XSIG_SEND;
-		    Process *rp = erts_pid2proc(BIF_P, ERTS_PROC_LOCK_MAIN,
-						tp[2], rp_locks);
-		    if (!rp) {
-			DECL_AM(dead);
-			BIF_RET(AM_dead);
-		    }
-
-		    if (BIF_P == rp)
-			rp_locks |= ERTS_PROC_LOCK_MAIN;
-		    xres = erts_send_exit_signal(NULL, /* NULL in order to
-							  force a pending exit
-							  when we send to our
-							  selves. */
-						 tp[1],
-						 rp,
-						 &rp_locks,
-						 tp[3],
-						 NIL,
-						 NULL,
-						 0);
-		    if (BIF_P == rp)
-			rp_locks &= ~ERTS_PROC_LOCK_MAIN;
-		    erts_proc_unlock(rp, rp_locks);
-		    if (xres > 1) {
-			DECL_AM(message);
-			BIF_RET(AM_message);
-		    }
-		    else if (xres == 0) {
-			DECL_AM(unaffected);
-			BIF_RET(AM_unaffected);
-		    }
-		    else {
-			DECL_AM(exit);
-			BIF_RET(AM_exit);
-		    }
-		}
-	    }
-	}
         else if (ERTS_IS_ATOM_STR("colliding_names", BIF_ARG_1)) {
 	    /* Used by ets_SUITE (stdlib) */
 	    if (is_tuple(BIF_ARG_2)) {
diff --git a/erts/emulator/beam/erl_bif_port.c b/erts/emulator/beam/erl_bif_port.c
index 1feb892b93..7fe4e02782 100644
--- a/erts/emulator/beam/erl_bif_port.c
+++ b/erts/emulator/beam/erl_bif_port.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2001-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2001-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -43,6 +43,7 @@
 #include "erl_bits.h"
 #include "erl_bif_unique.h"
 #include "dtrace-wrapper.h"
+#include "erl_proc_sig_queue.h"
 
 static Port *open_port(Process* p, Eterm name, Eterm settings, int *err_typep, int *err_nump);
 static int merge_global_environment(erts_osenv_t *env, Eterm key_value_pairs);
@@ -53,10 +54,13 @@ char *erts_default_arg0 = "default";
 
 BIF_RETTYPE erts_internal_open_port_2(BIF_ALIST_2)
 {
+    BIF_RETTYPE ret;
     Port *port;
     Eterm res;
     char *str;
     int err_type, err_num;
+    ErtsLinkData *ldp;
+    ErtsLink *lnk;
 
     port = open_port(BIF_P, BIF_ARG_1, BIF_ARG_2, &err_type, &err_num);
     if (!port) {
@@ -78,6 +82,16 @@ BIF_RETTYPE erts_internal_open_port_2(BIF_ALIST_2)
         BIF_RET(res);
     }
 
+    ldp = erts_link_create(ERTS_LNK_TYPE_PORT, BIF_P->common.id, port->common.id);
+    ASSERT(ldp->a.other.item == port->common.id);
+    ASSERT(ldp->b.other.item == BIF_P->common.id);
+    /*
+     * This link should not already be present, but can potentially
+     * due to id wrapping...
+     */
+    lnk = erts_link_tree_lookup_insert(&ERTS_P_LINKS(BIF_P), &ldp->a);
+    erts_link_tree_insert(&ERTS_P_LINKS(port), &ldp->b);
+
     if (port->drv_ptr->flags & ERL_DRV_FLAG_USE_INIT_ACK) {
 
         /* Copied from erl_port_task.c */
@@ -86,39 +100,30 @@ BIF_RETTYPE erts_internal_open_port_2(BIF_ALIST_2)
         erts_make_ref_in_array(port->async_open_port->ref);
         port->async_open_port->to = BIF_P->common.id;
 
-        erts_proc_lock(BIF_P, ERTS_PROC_LOCKS_MSG_RECEIVE | ERTS_PROC_LOCK_LINK);
-        if (ERTS_PROC_PENDING_EXIT(BIF_P)) {
-	    /* need to exit caller instead */
-	    erts_proc_unlock(BIF_P, ERTS_PROC_LOCKS_MSG_RECEIVE | ERTS_PROC_LOCK_LINK);
-	    KILL_CATCHES(BIF_P);
-	    BIF_P->freason = EXC_EXIT;
-            erts_port_release(port);
-            BIF_RET(am_badarg);
-	}
-
-	ERTS_MSGQ_MV_INQ2PRIVQ(BIF_P);
-	BIF_P->msg.save = BIF_P->msg.last;
-
-	erts_proc_unlock(BIF_P, ERTS_PROC_LOCKS_MSG_RECEIVE);
+        /*
+         * We unconditionaly *must* do a receive on a message
+         * containing the reference after this...
+         */
+        ERTS_RECV_MARK_SAVE(BIF_P);
+        ERTS_RECV_MARK_SET(BIF_P);
 
         res = erts_proc_store_ref(BIF_P, port->async_open_port->ref);
     } else {
         res = port->common.id;
-        erts_proc_lock(BIF_P, ERTS_PROC_LOCK_LINK);
     }
 
-    erts_add_link(&ERTS_P_LINKS(port), LINK_PID, BIF_P->common.id);
-    erts_add_link(&ERTS_P_LINKS(BIF_P), LINK_PID, port->common.id);
-
     if (IS_TRACED_FL(BIF_P, F_TRACE_PROCS))
-        trace_proc(BIF_P, ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_LINK, BIF_P,
+        trace_proc(BIF_P, ERTS_PROC_LOCK_MAIN, BIF_P,
                    am_link, port->common.id);
 
-    erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_LINK);
+    ERTS_BIF_PREP_RET(ret, res);
 
     erts_port_release(port);
 
-    BIF_RET(res);
+    if (lnk)
+        erts_link_release(lnk);
+
+    return ret;
 }
 
 static ERTS_INLINE Port *
@@ -195,7 +200,6 @@ BIF_RETTYPE erts_internal_port_command_3(BIF_ALIST_3)
 #endif
 
     switch (erts_port_output(BIF_P, flags, prt, prt->common.id, BIF_ARG_2, &ref)) {
-    case ERTS_PORT_OP_CALLER_EXIT:
     case ERTS_PORT_OP_BADARG:
     case ERTS_PORT_OP_DROPPED:
  	ERTS_BIF_PREP_RET(res, am_badarg);
@@ -254,7 +258,6 @@ BIF_RETTYPE erts_internal_port_call_3(BIF_ALIST_3)
     op = (unsigned int) uint_op;
 
     switch (erts_port_call(BIF_P, prt, op, BIF_ARG_3, &retval)) {
-    case ERTS_PORT_OP_CALLER_EXIT:
     case ERTS_PORT_OP_DROPPED:
     case ERTS_PORT_OP_BADARG:
 	retval = am_badarg;
@@ -272,11 +275,8 @@ BIF_RETTYPE erts_internal_port_call_3(BIF_ALIST_3)
     }
 
     state = erts_atomic32_read_acqb(&BIF_P->state);
-    if (state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_PENDING_EXIT)) {
-	if (state & ERTS_PSFLG_PENDING_EXIT)
-	    erts_handle_pending_exit(BIF_P, ERTS_PROC_LOCK_MAIN);
+    if (state & ERTS_PSFLG_EXITING)
 	ERTS_BIF_EXITED(BIF_P);
-    }
 
     BIF_RET(retval);
 }
@@ -302,7 +302,6 @@ BIF_RETTYPE erts_internal_port_control_3(BIF_ALIST_3)
     op = (unsigned int) uint_op;
 
     switch (erts_port_control(BIF_P, prt, op, BIF_ARG_3, &retval)) {
-    case ERTS_PORT_OP_CALLER_EXIT:
     case ERTS_PORT_OP_BADARG:
     case ERTS_PORT_OP_DROPPED:
 	retval = am_badarg;
@@ -320,11 +319,8 @@ BIF_RETTYPE erts_internal_port_control_3(BIF_ALIST_3)
     }
 
     state = erts_atomic32_read_acqb(&BIF_P->state);
-    if (state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_PENDING_EXIT)) {
-	if (state & ERTS_PSFLG_PENDING_EXIT)
-	    erts_handle_pending_exit(BIF_P, ERTS_PROC_LOCK_MAIN);
+    if (state & ERTS_PSFLG_EXITING)
 	ERTS_BIF_EXITED(BIF_P);
-    }
 
     BIF_RET(retval);
 }
@@ -347,7 +343,6 @@ BIF_RETTYPE erts_internal_port_close_1(BIF_ALIST_1)
 	BIF_RET(am_badarg);
 
     switch (erts_port_exit(BIF_P, 0, prt, BIF_P->common.id, am_normal, &ref)) {
-    case ERTS_PORT_OP_CALLER_EXIT:
     case ERTS_PORT_OP_BADARG:
     case ERTS_PORT_OP_DROPPED:
 	BIF_RET(am_badarg);
@@ -380,7 +375,6 @@ BIF_RETTYPE erts_internal_port_connect_2(BIF_ALIST_2)
 #endif
 
     switch (erts_port_connect(BIF_P, 0, prt, BIF_P->common.id, BIF_ARG_2, &ref)) {
-    case ERTS_PORT_OP_CALLER_EXIT:
     case ERTS_PORT_OP_BADARG:
     case ERTS_PORT_OP_DROPPED:
 	BIF_RET(am_badarg);
@@ -418,7 +412,6 @@ BIF_RETTYPE erts_internal_port_info_1(BIF_ALIST_1)
     }
 
     switch (erts_port_info(BIF_P, prt, THE_NON_VALUE, &retval)) {
-    case ERTS_PORT_OP_CALLER_EXIT:
     case ERTS_PORT_OP_BADARG:
 	BIF_RET(am_badarg);
     case ERTS_PORT_OP_DROPPED:
@@ -457,7 +450,6 @@ BIF_RETTYPE erts_internal_port_info_2(BIF_ALIST_2)
     }
 
     switch (erts_port_info(BIF_P, prt, BIF_ARG_2, &retval)) {
-    case ERTS_PORT_OP_CALLER_EXIT:
     case ERTS_PORT_OP_BADARG:
 	BIF_RET(am_badarg);
     case ERTS_PORT_OP_DROPPED:
diff --git a/erts/emulator/beam/erl_bif_trace.c b/erts/emulator/beam/erl_bif_trace.c
index 22942b40c4..a076f0bf54 100644
--- a/erts/emulator/beam/erl_bif_trace.c
+++ b/erts/emulator/beam/erl_bif_trace.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1999-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1999-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -40,6 +40,7 @@
 #include "erl_binary.h"
 #include "erl_thr_progress.h"
 #include "erl_bif_unique.h"
+#include "erl_proc_sig_queue.h"
 
 #define DECL_AM(S) Eterm AM_ ## S = am_atom_put(#S, sizeof(#S) - 1)
 
diff --git a/erts/emulator/beam/erl_db_util.c b/erts/emulator/beam/erl_db_util.c
index f21db4b65b..1e8e9e5e94 100644
--- a/erts/emulator/beam/erl_db_util.c
+++ b/erts/emulator/beam/erl_db_util.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1998-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1998-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -38,6 +38,7 @@
 #include "erl_binary.h"
 #include "erl_map.h"
 #include "erl_thr_progress.h"
+#include "erl_proc_sig_queue.h"
 
 #include "erl_db_util.h"
 
@@ -176,6 +177,7 @@ set_tracee_flags(Process *tracee_p, ErtsTracer tracer,
 	   : am_false);
     erts_tracer_replace(&tracee_p->common, tracer);
     ERTS_TRACE_FLAGS(tracee_p) = flags;
+
     return ret;
 }
 /*
diff --git a/erts/emulator/beam/erl_debug.c b/erts/emulator/beam/erl_debug.c
index bf8244564a..db78378257 100644
--- a/erts/emulator/beam/erl_debug.c
+++ b/erts/emulator/beam/erl_debug.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1998-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1998-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -404,15 +404,16 @@ void verify_process(Process *p)
         erts_exit(ERTS_ERROR_EXIT,"Wild pointer found in " name " of %T!\n",p->common.id); }
 
 
-    ErtsMessage* mp = p->msg.first;
-
     VERBOSE(DEBUG_MEMORY,("Verify process: %T...\n",p->common.id));
 
-    while (mp != NULL) {
-        VERIFY_ETERM("message term",ERL_MESSAGE_TERM(mp));
-        VERIFY_ETERM("message token",ERL_MESSAGE_TOKEN(mp));
-        mp = mp->next;
-    }
+    ERTS_FOREACH_SIG_PRIVQS(
+        p, mp,
+        {
+            if (ERTS_SIG_IS_MSG(mp)) {
+                VERIFY_ETERM("message term",ERL_MESSAGE_TERM(mp));
+                VERIFY_ETERM("message token",ERL_MESSAGE_TOKEN(mp));
+            }
+        });
 
     erts_check_stack(p);
     erts_check_heap(p);
@@ -532,16 +533,15 @@ static void print_process_memory(Process *p)
     erts_printf("-- %-*s ---%s-%s-%s-%s--\n",
                 PTR_SIZE, "PCB", dashes, dashes, dashes, dashes);
 
-    if (p->msg.first != NULL) {
-        ErtsMessage* mp;
-        erts_printf("  Message Queue:\n");
-        mp = p->msg.first;
-        while (mp != NULL) {
-            erts_printf("| 0x%0*lx | 0x%0*lx |\n",PTR_SIZE,
-                        ERL_MESSAGE_TERM(mp),PTR_SIZE,ERL_MESSAGE_TOKEN(mp));
-            mp = mp->next;
-        }
-    }
+
+    erts_printf("  Message Queue:\n");
+    ERTS_FOREACH_SIG_PRIVQS(
+        p, mp,
+        {
+            if (ERTS_SIG_IS_MSG(mp))
+                erts_printf("| 0x%0*lx | 0x%0*lx |\n",PTR_SIZE,
+                            ERL_MESSAGE_TERM(mp),PTR_SIZE,ERL_MESSAGE_TOKEN(mp));
+        });
 
     if (p->dictionary != NULL) {
         int n = ERTS_PD_SIZE(p->dictionary);
diff --git a/erts/emulator/beam/erl_gc.c b/erts/emulator/beam/erl_gc.c
index 1c64644efc..5da8e3eda5 100644
--- a/erts/emulator/beam/erl_gc.c
+++ b/erts/emulator/beam/erl_gc.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2002-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2002-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -43,6 +43,7 @@
 #include "erl_bif_unique.h"
 #include "dist.h"
 #include "erl_nfunc_sched.h"
+#include "erl_proc_sig_queue.h"
 
 #define ERTS_INACT_WR_PB_LEAVE_MUCH_LIMIT 1
 #define ERTS_INACT_WR_PB_LEAVE_MUCH_PERCENTAGE 20
@@ -154,7 +155,6 @@ static void offset_rootset(Process *p, Sint offs, char* area, Uint area_size,
 			   Eterm* objv, int nobj);
 static void offset_off_heap(Process* p, Sint offs, char* area, Uint area_size);
 static void offset_mqueue(Process *p, Sint offs, char* area, Uint area_size);
-static void move_msgq_to_heap(Process *p);
 static int reached_max_heap_size(Process *p, Uint total_heap_size,
                                  Uint extra_heap_size, Uint extra_old_heap_size);
 static void init_gc_info(ErtsGCInfo *gcip);
@@ -189,6 +189,21 @@ static struct {
     ErtsGCInfo info;
 } dirty_gc;
 
+static void move_msgs_to_heap(Process *c_p)
+{
+    Uint64 pre_oh, post_oh;
+
+    pre_oh = c_p->off_heap.overhead;
+    erts_proc_sig_move_msgs_to_heap(c_p);
+    post_oh = c_p->off_heap.overhead;
+
+    if (pre_oh != post_oh) {
+	/* Got new binaries; update bin vheap size... */
+        c_p->bin_vheap_sz = next_vheap_size(c_p, post_oh,
+                                            c_p->bin_vheap_sz);
+    }
+}
+
 static ERTS_INLINE int
 gc_cost(Uint gc_moved_live_words, Uint resize_moved_words)
 {
@@ -565,20 +580,26 @@ young_gen_usage(Process *p)
     hsz = p->mbuf_sz;
 
     if (p->flags & F_ON_HEAP_MSGQ) {
-	ErtsMessage *mp;
-	for (mp = p->msg.first; mp; mp = mp->next) {
-	    /*
-	     * We leave not yet decoded distribution messages
-	     * as they are in the queue since it is not
-	     * possible to determine a maximum size until
-	     * actual decoding. However, we use their estimated
-	     * size when calculating need, and by this making
-	     * it more likely that they will fit on the heap
-	     * when actually decoded.
-	     */
-	    if (mp->data.attached)
-		hsz += erts_msg_attached_data_size(mp);
-	}
+        ERTS_FOREACH_SIG_PRIVQS(
+            p, mp,
+            {
+                /*
+                 * We leave not yet decoded distribution messages
+                 * as they are in the queue since it is not
+                 * possible to determine a maximum size until
+                 * actual decoding. However, we use their estimated
+                 * size when calculating need, and by this making
+                 * it more likely that they will fit on the heap
+                 * when actually decoded.
+                 *
+                 * We however ignore off heap messages...
+                 */
+                if (ERTS_SIG_IS_MSG(mp)
+                    && mp->data.attached
+                    && mp->data.attached != ERTS_MSG_COMBINED_HFRAG) {
+                    hsz += erts_msg_attached_data_size(mp);
+                }
+            });
     }
 
     hsz += p->htop - p->heap;
@@ -621,7 +642,7 @@ check_for_possibly_long_gc(Process *p, Uint ygen_usage)
     sz = ygen_usage;
     sz += p->hend - p->stop;
     if (p->flags & F_ON_HEAP_MSGQ)
-        sz += p->msg.len;
+        sz += p->sig_qs.len;
     if (major)
 	sz += p->old_htop - p->old_heap;
 
@@ -761,13 +782,9 @@ do_major_collection:
        long_gc/large_gc triggers when this happens as process was
        killed before a GC could be done. */
     if (reds == -2) {
-        ErtsProcLocks locks = ERTS_PROC_LOCKS_ALL;
         int res;
 
-        erts_proc_lock(p, ERTS_PROC_LOCKS_ALL_MINOR);
-        erts_send_exit_signal(p, p->common.id, p, &locks,
-                              am_kill, NIL, NULL, 0);
-        erts_proc_unlock(p, locks & ERTS_PROC_LOCKS_ALL_MINOR);
+        erts_set_self_exiting(p, am_killed);
 
     delay_gc_after_start:
         /* erts_send_exit_signal looks for ERTS_PSFLG_GC, so
@@ -1375,7 +1392,7 @@ minor_collection(Process* p, ErlHeapFragment *live_hf_end,
 		 new_sz, objv, nobj);
 
 	if (p->flags & F_ON_HEAP_MSGQ)
-	    move_msgq_to_heap(p);
+	    move_msgs_to_heap(p);
 
 	new_mature = p->old_htop - prev_old_htop;
 
@@ -1760,7 +1777,7 @@ major_collection(Process* p, ErlHeapFragment *live_hf_end,
     HIGH_WATER(p) = HEAP_TOP(p);
 
     if (p->flags & F_ON_HEAP_MSGQ)
-	move_msgq_to_heap(p);
+	move_msgs_to_heap(p);
 
     ErtsGcQuickSanityCheck(p);
 
@@ -2332,9 +2349,9 @@ collect_live_heap_frags(Process* p, ErlHeapFragment *live_hf_end, Eterm* n_htop)
     return n_htop;
 }
 
-static ERTS_INLINE void
-copy_one_frag(Eterm** hpp, ErlOffHeap* off_heap,
-	      ErlHeapFragment *bp, Eterm *refs, int nrefs)
+void
+erts_copy_one_frag(Eterm** hpp, ErlOffHeap* off_heap,
+                   ErlHeapFragment *bp, Eterm *refs, int nrefs)
 {
     Uint sz;
     int i;
@@ -2440,61 +2457,6 @@ copy_one_frag(Eterm** hpp, ErlOffHeap* off_heap,
     bp->off_heap.first = NULL;
 }
 
-static void
-move_msgq_to_heap(Process *p)
-{
-    
-    ErtsMessage **mpp = &p->msg.first;
-    Uint64 pre_oh = MSO(p).overhead;
-
-    while (*mpp) {
-	ErtsMessage *mp = *mpp;
-
-	if (mp->data.attached) {
-	    ErlHeapFragment *bp;
-
-	    /*
-	     * We leave not yet decoded distribution messages
-	     * as they are in the queue since it is not
-	     * possible to determine a maximum size until
-	     * actual decoding...
-	     */
-	    if (is_value(ERL_MESSAGE_TERM(mp))) {
-
-                bp = erts_message_to_heap_frag(mp);
-
-		if (bp->next)
-		    erts_move_multi_frags(&p->htop, &p->off_heap, bp,
-					  mp->m, ERL_MESSAGE_REF_ARRAY_SZ, 0);
-		else
-		    copy_one_frag(&p->htop, &p->off_heap, bp,
-				  mp->m, ERL_MESSAGE_REF_ARRAY_SZ);
-
-		if (mp->data.attached != ERTS_MSG_COMBINED_HFRAG) {
-		    mp->data.heap_frag = NULL;
-		    free_message_buffer(bp);
-		}
-		else {
-		    ErtsMessage *new_mp = erts_alloc_message(0, NULL);
-		    sys_memcpy((void *) new_mp->m, (void *) mp->m,
-			       sizeof(Eterm)*ERL_MESSAGE_REF_ARRAY_SZ);
-		    erts_msgq_replace_msg_ref(&p->msg, new_mp, mpp);
-		    mp->next = NULL;
-		    erts_cleanup_messages(mp);
-		    mp = new_mp;
-		}
-	    }
-	}
-
-	mpp = &(*mpp)->next;
-    }
-
-    if (pre_oh != MSO(p).overhead) {
-	/* Got new binaries; update vheap size... */
-	BIN_VHEAP_SZ(p) = next_vheap_size(p, MSO(p).overhead, BIN_VHEAP_SZ(p));
-    }
-}
-
 static Uint
 setup_rootset(Process *p, Eterm *objv, int nobj, Rootset *rootset)
 {
@@ -2583,11 +2545,10 @@ setup_rootset(Process *p, Eterm *objv, int nobj, Rootset *rootset)
 	 * We do not have off heap message queue enabled, i.e. we
 	 * need to add message queue to rootset...
 	 */
-	ErtsMessage *mp;
 
 	/* Ensure large enough rootset... */
-	if (n + p->msg.len > rootset->size) {
-	    Uint new_size = n + p->msg.len;
+	if (n + p->sig_qs.len > rootset->size) {
+	    Uint new_size = n + p->sig_qs.len;
 	    ERTS_GC_ASSERT(roots == rootset->def);
 	    roots = erts_alloc(ERTS_ALC_T_ROOTSET,
 			       new_size*sizeof(Roots));
@@ -2595,18 +2556,19 @@ setup_rootset(Process *p, Eterm *objv, int nobj, Rootset *rootset)
 	    rootset->size = new_size;
 	}
 
-	for (mp = p->msg.first; mp; mp = mp->next) {
-
-	    if (!mp->data.attached) {
-		/*
-		 * Message may refer data on heap;
-		 * add it to rootset...
-		 */
-		roots[n].v = mp->m;
-		roots[n].sz = ERL_MESSAGE_REF_ARRAY_SZ;
-		n++;
-	    }
-	}
+        ERTS_FOREACH_SIG_PRIVQS(
+            p, mp,
+            {
+                if (ERTS_SIG_IS_INTERNAL_MSG(mp) && !mp->data.attached) {
+                    /*
+                     * Message may refer data on heap;
+                     * add it to rootset...
+                     */
+                    roots[n].v = mp->m;
+                    roots[n].sz = ERL_MESSAGE_REF_ARRAY_SZ;
+                    n++;
+                }
+            });
 	break;
     }
     }
@@ -3117,51 +3079,59 @@ offset_off_heap(Process* p, Sint offs, char* area, Uint area_size)
     }
 }
 
+#ifndef USE_VM_PROBES
+#define ERTS_OFFSET_DT_UTAG(MP, A, ASZ, O)
+#else
+#define ERTS_OFFSET_DT_UTAG(MP, A, ASZ, O)                                      \
+    do {                                                                        \
+        Eterm utag__ = ERL_MESSAGE_DT_UTAG((MP));                               \
+        if (is_boxed(utag__) && ErtsInArea(ptr_val(utag__), (A), (ASZ))) {      \
+            ERL_MESSAGE_DT_UTAG((MP)) = offset_ptr(utag__, (O));                \
+        }                                                                       \
+    } while (0)
+#endif
+
+static ERTS_INLINE void
+offset_message(ErtsMessage *mp, Sint offs, char* area, Uint area_size)
+{
+    Eterm mesg = ERL_MESSAGE_TERM(mp);
+    if (ERTS_SIG_IS_MSG_TAG(mesg)) {
+        if (ERTS_SIG_IS_INTERNAL_MSG_TAG(mesg)) {
+            switch (primary_tag(mesg)) {
+            case TAG_PRIMARY_LIST:
+            case TAG_PRIMARY_BOXED:
+                if (ErtsInArea(ptr_val(mesg), area, area_size)) {
+                    ERL_MESSAGE_TERM(mp) = offset_ptr(mesg, offs);
+                }
+                break;
+            }
+        }
+        mesg = ERL_MESSAGE_TOKEN(mp);
+        if (is_boxed(mesg) && ErtsInArea(ptr_val(mesg), area, area_size)) {
+            ERL_MESSAGE_TOKEN(mp) = offset_ptr(mesg, offs);
+        }
+
+        ERTS_OFFSET_DT_UTAG(mp, area, area_size, offs);
+	
+        ASSERT((is_nil(ERL_MESSAGE_TOKEN(mp)) ||
+                is_tuple(ERL_MESSAGE_TOKEN(mp)) ||
+                is_atom(ERL_MESSAGE_TOKEN(mp))));
+    }
+}
+
 /*
  * Offset pointers in message queue.
  */
 static void
 offset_mqueue(Process *p, Sint offs, char* area, Uint area_size)
 {
-    ErtsMessage* mp = p->msg.first;
-
-    if ((p->flags & (F_OFF_HEAP_MSGQ|F_OFF_HEAP_MSGQ_CHNG)) != F_OFF_HEAP_MSGQ) {
-
-	while (mp != NULL) {
-	    Eterm mesg = ERL_MESSAGE_TERM(mp);
-	    if (is_value(mesg)) {
-		switch (primary_tag(mesg)) {
-		case TAG_PRIMARY_LIST:
-		case TAG_PRIMARY_BOXED:
-		    if (ErtsInArea(ptr_val(mesg), area, area_size)) {
-			ERL_MESSAGE_TERM(mp) = offset_ptr(mesg, offs);
-		    }
-		    break;
-		}
-	    }
-	    mesg = ERL_MESSAGE_TOKEN(mp);
-	    if (is_boxed(mesg) && ErtsInArea(ptr_val(mesg), area, area_size)) {
-		ERL_MESSAGE_TOKEN(mp) = offset_ptr(mesg, offs);
-	    }
-#ifdef USE_VM_PROBES
-	    mesg = ERL_MESSAGE_DT_UTAG(mp);
-	    if (is_boxed(mesg) && ErtsInArea(ptr_val(mesg), area, area_size)) {
-		ERL_MESSAGE_DT_UTAG(mp) = offset_ptr(mesg, offs);
-	    }
-#endif	
-	
-	    ASSERT((is_nil(ERL_MESSAGE_TOKEN(mp)) ||
-		    is_tuple(ERL_MESSAGE_TOKEN(mp)) ||
-		    is_atom(ERL_MESSAGE_TOKEN(mp))));
-	    mp = mp->next;
-	}
-
-    }
+    if ((p->flags & (F_OFF_HEAP_MSGQ|F_OFF_HEAP_MSGQ_CHNG)) != F_OFF_HEAP_MSGQ)
+        ERTS_FOREACH_SIG_PRIVQS(p, mp, offset_message(mp, offs, area, area_size));
 }
 
 static void ERTS_INLINE
 offset_one_rootset(Process *p, Sint offs, char* area, Uint area_size,
-	       Eterm* objv, int nobj)
+                   Eterm* objv, int nobj)
 {
     Eterm *v;
     Uint sz;
@@ -3378,7 +3348,6 @@ erts_process_gc_info(Process *p, Uint *sizep, Eterm **hpp,
     };
 
     Eterm res = THE_NON_VALUE;
-    ErtsMessage *mp;
 
     ERTS_CT_ASSERT(sizeof(values)/sizeof(*values) == sizeof(tags)/sizeof(*tags));
     ERTS_CT_ASSERT(sizeof(values)/sizeof(*values) == ERTS_PROCESS_GC_INFO_MAX_TERMS);
@@ -3397,9 +3366,15 @@ erts_process_gc_info(Process *p, Uint *sizep, Eterm **hpp,
            be the same as adding old_heap_block_size + heap_block_size
            + mbuf_size.
         */
-        for (mp = p->msg.first; mp; mp = mp->next)
-            if (mp->data.attached)
-                values[2] += erts_msg_attached_data_size(mp);
+        ERTS_FOREACH_SIG_PRIVQS(
+            p, mp,
+            {
+                if (ERTS_SIG_IS_MSG(mp)
+                    && mp->data.attached
+                    && mp->data.attached != ERTS_MSG_COMBINED_HFRAG) {
+                    values[2] += erts_msg_attached_data_size(mp);
+                }
+            });
     }
 
     res = erts_bld_atom_uword_2tup_list(hpp,
diff --git a/erts/emulator/beam/erl_gc.h b/erts/emulator/beam/erl_gc.h
index dec0ab1143..63d03cdf8b 100644
--- a/erts/emulator/beam/erl_gc.h
+++ b/erts/emulator/beam/erl_gc.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2007-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2007-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -181,6 +181,8 @@ void erts_free_heap_frags(struct process* p);
 Eterm erts_max_heap_size_map(Sint, Uint, Eterm **, Uint *);
 int erts_max_heap_size(Eterm, Uint *, Uint *);
 void erts_deallocate_young_generation(Process *c_p);
+void erts_copy_one_frag(Eterm** hpp, ErlOffHeap* off_heap,
+                        ErlHeapFragment *bp, Eterm *refs, int nrefs);
 #if defined(DEBUG) || defined(ERTS_OFFHEAP_DEBUG)
 int erts_dbg_within_proc(Eterm *ptr, Process *p, Eterm* real_htop);
 #endif
diff --git a/erts/emulator/beam/erl_hl_timer.c b/erts/emulator/beam/erl_hl_timer.c
index bda2c9b94d..6ec6f8065e 100644
--- a/erts/emulator/beam/erl_hl_timer.c
+++ b/erts/emulator/beam/erl_hl_timer.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  * 
- * Copyright Ericsson AB 2015-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2015-2018. All Rights Reserved.
  * 
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -38,6 +38,7 @@
 #define ERTS_WANT_TIMER_WHEEL_API
 #include "erl_time.h"
 #include "erl_hl_timer.h"
+#include "erl_proc_sig_queue.h"
 #ifdef ERTS_MAGIC_REF_BIF_TIMERS
 #include "erl_binary.h"
 #endif
@@ -2470,28 +2471,21 @@ access_bif_timer(Process *c_p, Eterm tref, int cancel, int async, int info)
 	    req->rrefn[1] = rrefn[1];
 	    req->rrefn[2] = rrefn[2];
 
-	    erts_proc_lock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
-
-	    if (ERTS_PROC_PENDING_EXIT(c_p))
-		ERTS_VBUMP_ALL_REDS(c_p);
-	    else {
-		/*
-		 * Caller needs to wait for a message containing
-		 * the ref that we just created. No such message
-		 * can exist in callers message queue at this time.
-		 * We therefore move the save pointer of the
-		 * callers message queue to the end of the queue.
-		 *
-		 * NOTE: It is of vital importance that the caller
-		 *       immediately do a receive unconditionaly
-		 *       waiting for the message with the reference;
-		 *       otherwise, next receive will *not* work
-		 *       as expected!
-		 */
-		ERTS_MSGQ_MV_INQ2PRIVQ(c_p);
-		c_p->msg.save = c_p->msg.last;
-	    }
-	    erts_proc_unlock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
+            /*
+             * Caller needs to wait for a message containing
+             * the ref that we just created. No such message
+             * can exist in callers message queue at this time.
+             * We therefore move the save pointer of the
+             * callers message queue to the end of the queue.
+             *
+             * NOTE: It is of vital importance that the caller
+             *       immediately do a receive unconditionaly
+             *       waiting for the message with the reference;
+             *       otherwise, next receive will *not* work
+             *       as expected!
+             */
+            ERTS_RECV_MARK_SAVE(c_p);
+            ERTS_RECV_MARK_SET(c_p);
 
 	    ERTS_BIF_PREP_TRAP1(ret, erts_await_result, c_p, rref);
 	}
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 8430a5559b..83ed2e4cd6 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1997-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1997-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -51,6 +51,8 @@
 #include "erl_time.h"
 #include "erl_check_io.h"
 #include "erl_osenv.h"
+#include "erl_proc_sig_queue.h"
+
 #ifdef HIPE
 #include "hipe_mode_switch.h"	/* for hipe_mode_switch_init() */
 #include "hipe_signal.h"	/* for hipe_signal_init() */
@@ -126,6 +128,8 @@ const Eterm etp_hole_marker = 0;
 
 static int modified_sched_thread_suggested_stack_size = 0;
 
+Eterm erts_init_process_id;
+
 /*
  * Note about VxWorks: All variables must be initialized by executable code,
  * not by an initializer. Otherwise a new instance of the emulator will
@@ -304,8 +308,9 @@ erl_init(int ncpu,
 	 int node_tab_delete_delay,
 	 ErtsDbSpinCount db_spin_count)
 {
+    erts_monitor_link_init();
+    erts_proc_sig_queue_init();
     erts_bif_unique_init();
-    erts_init_monitors();
     erts_init_time(time_correction, time_warp_mode);
     erts_init_sys_common_misc();
     erts_init_process(ncpu, proc_tab_sz, legacy_proc_tab);
@@ -413,7 +418,7 @@ erl_first_process_otp(char* modname, void* code, unsigned size, int argc, char**
 }
 
 static Eterm
-erl_system_process_otp(Eterm parent_pid, char* modname, int off_heap_msgq)
+erl_system_process_otp(Eterm parent_pid, char* modname, int off_heap_msgq, int prio)
 {
     Eterm start_mod;
     Process* parent;
@@ -428,9 +433,16 @@ erl_system_process_otp(Eterm parent_pid, char* modname, int off_heap_msgq)
 
     parent = erts_pid2proc(NULL, 0, parent_pid, ERTS_PROC_LOCK_MAIN);
 
-    so.flags = erts_default_spo_flags|SPO_SYSTEM_PROC;
+    so.flags = erts_default_spo_flags|SPO_SYSTEM_PROC|SPO_USE_ARGS;
     if (off_heap_msgq)
         so.flags |= SPO_OFF_HEAP_MSGQ;
+    so.min_heap_size    = H_MIN_SIZE;
+    so.min_vheap_size   = BIN_VH_MIN_SIZE;
+    so.max_heap_size    = H_MAX_SIZE;
+    so.max_heap_flags   = H_MAX_FLAGS;
+    so.priority         = prio;
+    so.max_gen_gcs      = (Uint16) erts_atomic32_read_nob(&erts_max_gen_gcs);
+    so.scheduler        = 0;
     res = erl_create_process(parent, start_mod, am_start, NIL, &so);
     erts_proc_unlock(parent, ERTS_PROC_LOCK_MAIN);
     return res;
@@ -1200,7 +1212,6 @@ erl_start(int argc, char **argv)
     ErtsTimeWarpMode time_warp_mode;
     int node_tab_delete_delay = ERTS_NODE_TAB_DELAY_GC_DEFAULT;
     ErtsDbSpinCount db_spin_count = ERTS_DB_SPNCNT_NORMAL;
-    Eterm otp_ring0_pid;
 
     set_default_time_adj(&time_correction,
 			 &time_warp_mode);
@@ -2191,8 +2202,8 @@ erl_start(int argc, char **argv)
 
     erts_initialized = 1;
 
-    otp_ring0_pid = erl_first_process_otp("otp_ring0", NULL, 0,
-					  boot_argc, boot_argv);
+    erts_init_process_id = erl_first_process_otp("otp_ring0", NULL, 0,
+                                                 boot_argc, boot_argv);
 
     {
 	/*
@@ -2202,14 +2213,18 @@ erl_start(int argc, char **argv)
 	 */
 	Eterm pid;
 
-	pid = erl_system_process_otp(otp_ring0_pid, "erts_code_purger", !0);
+	pid = erl_system_process_otp(erts_init_process_id,
+                                     "erts_code_purger", !0,
+                                     PRIORITY_NORMAL);
 	erts_code_purger
 	    = (Process *) erts_ptab_pix2intptr_ddrb(&erts_proc,
 						    internal_pid_index(pid));
 	ASSERT(erts_code_purger && erts_code_purger->common.id == pid);
 	erts_proc_inc_refc(erts_code_purger); 
 
-	pid = erl_system_process_otp(otp_ring0_pid, "erts_literal_area_collector", !0);
+	pid = erl_system_process_otp(erts_init_process_id,
+                                     "erts_literal_area_collector",
+                                     !0, PRIORITY_NORMAL);
 	erts_literal_area_collector
 	    = (Process *) erts_ptab_pix2intptr_ddrb(&erts_proc,
 						    internal_pid_index(pid));
@@ -2217,14 +2232,35 @@ erl_start(int argc, char **argv)
 	       && erts_literal_area_collector->common.id == pid);
 	erts_proc_inc_refc(erts_literal_area_collector);
 
-	pid = erl_system_process_otp(otp_ring0_pid, "erts_dirty_process_code_checker", !0);
-	erts_dirty_process_code_checker
+	pid = erl_system_process_otp(erts_init_process_id,
+                                     "erts_dirty_process_signal_handler",
+                                     !0, PRIORITY_NORMAL);
+        erts_dirty_process_signal_handler
 	    = (Process *) erts_ptab_pix2intptr_ddrb(&erts_proc,
 						    internal_pid_index(pid));
-	ASSERT(erts_dirty_process_code_checker
-	       && erts_dirty_process_code_checker->common.id == pid);
-	erts_proc_inc_refc(erts_dirty_process_code_checker);
-
+	ASSERT(erts_dirty_process_signal_handler
+	       && erts_dirty_process_signal_handler->common.id == pid);
+	erts_proc_inc_refc(erts_dirty_process_signal_handler);
+
+	pid = erl_system_process_otp(erts_init_process_id,
+                                     "erts_dirty_process_signal_handler",
+                                     !0, PRIORITY_HIGH);
+        erts_dirty_process_signal_handler_high
+	    = (Process *) erts_ptab_pix2intptr_ddrb(&erts_proc,
+						    internal_pid_index(pid));
+	ASSERT(erts_dirty_process_signal_handler_high
+	       && erts_dirty_process_signal_handler_high->common.id == pid);
+	erts_proc_inc_refc(erts_dirty_process_signal_handler_high);
+
+	pid = erl_system_process_otp(erts_init_process_id,
+                                     "erts_dirty_process_signal_handler",
+                                     !0, PRIORITY_MAX);
+        erts_dirty_process_signal_handler_max
+	    = (Process *) erts_ptab_pix2intptr_ddrb(&erts_proc,
+						    internal_pid_index(pid));
+	ASSERT(erts_dirty_process_signal_handler_max
+	       && erts_dirty_process_signal_handler_max->common.id == pid);
+	erts_proc_inc_refc(erts_dirty_process_signal_handler_max);
     }
 
     erts_start_schedulers();
diff --git a/erts/emulator/beam/erl_lock_check.c b/erts/emulator/beam/erl_lock_check.c
index 773b138d92..0ced5ec310 100644
--- a/erts/emulator/beam/erl_lock_check.c
+++ b/erts/emulator/beam/erl_lock_check.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2005-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2005-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -92,7 +92,6 @@ static erts_lc_lock_order_t erts_lock_order[] = {
     {	"db_hash_slot",				"address"		},
     {	"resource_monitors",			"address"	        },
     {   "driver_list",                          NULL                    },
-    {	"proc_link",				"pid"			},
     {	"proc_msgq",				"pid"			},
     {	"proc_btm",				"pid"			},
     {	"dist_entry",				"address"		},
diff --git a/erts/emulator/beam/erl_message.c b/erts/emulator/beam/erl_message.c
index 6f7c71ef98..ed7a9d37c2 100644
--- a/erts/emulator/beam/erl_message.c
+++ b/erts/emulator/beam/erl_message.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1997-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1997-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,6 +33,7 @@
 #include "erl_binary.h"
 #include "dtrace-wrapper.h"
 #include "beam_bp.h"
+#include "erl_proc_sig_queue.h"
 
 ERTS_SCHED_PREF_QUICK_ALLOC_IMPL(message_ref,
 				 ErtsMessageRef,
@@ -207,7 +208,7 @@ erts_cleanup_messages(ErtsMessage *msgp)
     while (mp) {
 	ErtsMessage *fmp;
 	ErlHeapFragment *bp;
-	if (is_non_value(ERL_MESSAGE_TERM(mp))) {
+	if (ERTS_SIG_IS_EXTERNAL_MSG(mp)) {
 	    if (is_not_immed(ERL_MESSAGE_TOKEN(mp))) {
 		bp = (ErlHeapFragment *) mp->data.dist_ext->ext_endp;
 		erts_cleanup_offheap(&bp->off_heap);
@@ -215,10 +216,13 @@ erts_cleanup_messages(ErtsMessage *msgp)
 	    if (mp->data.dist_ext)
 		erts_free_dist_ext_copy(mp->data.dist_ext);
 	}
-	else {
-	    if (mp->data.attached != ERTS_MSG_COMBINED_HFRAG)
+        else {
+	    if (ERTS_SIG_IS_INTERNAL_MSG(mp)
+                && mp->data.attached != ERTS_MSG_COMBINED_HFRAG) {
 		bp = mp->data.heap_frag;
+            }
 	    else {
+                mp->data.attached = ERTS_MSG_COMBINED_HFRAG;
 		bp = mp->hfrag.next;
 		erts_cleanup_offheap(&mp->hfrag.off_heap);
 	    }
@@ -272,6 +276,7 @@ erts_queue_dist_message(Process *rcvr,
     mp = erts_alloc_message(0, NULL);
     mp->data.dist_ext = dist_ext;
 
+    ERL_MESSAGE_FROM(mp) = dist_ext->dep->sysname;
     ERL_MESSAGE_TERM(mp) = THE_NON_VALUE;
 #ifdef USE_VM_PROBES
     ERL_MESSAGE_DT_UTAG(mp) = NIL;
@@ -294,46 +299,15 @@ erts_queue_dist_message(Process *rcvr,
 	}
     }
 
+
     state = erts_atomic32_read_acqb(&rcvr->state);
-    if (state & (ERTS_PSFLG_PENDING_EXIT|ERTS_PSFLG_EXITING)) {
+    if (state & ERTS_PSFLG_EXITING) {
 	if (!(rcvr_locks & ERTS_PROC_LOCK_MSGQ))
 	    erts_proc_unlock(rcvr, ERTS_PROC_LOCK_MSGQ);
 	/* Drop message if receiver is exiting or has a pending exit ... */
 	erts_cleanup_messages(mp);
     }
-    else
-    if (IS_TRACED_FL(rcvr, F_TRACE_RECEIVE)) {
-        if (from == am_Empty)
-            from = dist_ext->dep->sysname;
-
-	/* Ahh... need to decode it in order to trace it... */
-	if (!(rcvr_locks & ERTS_PROC_LOCK_MSGQ))
-	    erts_proc_unlock(rcvr, ERTS_PROC_LOCK_MSGQ);
-	if (!erts_decode_dist_message(rcvr, rcvr_locks, mp, 0))
-	    erts_free_message(mp);
-	else {
-	    Eterm msg = ERL_MESSAGE_TERM(mp);
-	    token = ERL_MESSAGE_TOKEN(mp);
-#ifdef USE_VM_PROBES
-	    if (DTRACE_ENABLED(message_queued)) {
-		DTRACE_CHARBUF(receiver_name, DTRACE_TERM_BUF_SIZE);
-
-		dtrace_proc_str(rcvr, receiver_name);
-                if (have_seqtrace(token)) {
-		    tok_label = signed_val(SEQ_TRACE_T_LABEL(token));
-		    tok_lastcnt = signed_val(SEQ_TRACE_T_LASTCNT(token));
-		    tok_serial = signed_val(SEQ_TRACE_T_SERIAL(token));
-		}
-		DTRACE6(message_queued,
-			receiver_name, size_object(msg), rcvr->msg.len,
-			tok_label, tok_lastcnt, tok_serial);
-	    }
-#endif
-	    erts_queue_message(rcvr, rcvr_locks, mp, msg, from);
-	}
-    }
     else {
-	/* Enqueue message on external format */
 
 #ifdef USE_VM_PROBES
         if (DTRACE_ENABLED(message_queued)) {
@@ -359,9 +333,7 @@ erts_queue_dist_message(Process *rcvr,
 	if (!(rcvr_locks & ERTS_PROC_LOCK_MSGQ))
 	    erts_proc_unlock(rcvr, ERTS_PROC_LOCK_MSGQ);
 
-	erts_proc_notify_new_message(rcvr,
-				     rcvr_locks
-	    );
+	erts_proc_notify_new_message(rcvr, rcvr_locks);
     }
 }
 
@@ -372,15 +344,14 @@ queue_messages(Process* receiver,
                ErtsProcLocks receiver_locks,
                ErtsMessage* first,
                ErtsMessage** last,
-               Uint len,
-               Eterm from)
+               Uint len)
 {
-    ErtsTracingEvent* te;
     Sint res;
     int locked_msgq = 0;
     erts_aint32_t state;
 
     ASSERT(is_value(ERL_MESSAGE_TERM(first)));
+    ASSERT(is_value(ERL_MESSAGE_FROM(first)));
     ASSERT(ERL_MESSAGE_TOKEN(first) == am_undefined ||
            ERL_MESSAGE_TOKEN(first) == NIL ||
            is_tuple(ERL_MESSAGE_TOKEN(first)));
@@ -398,7 +369,7 @@ queue_messages(Process* receiver,
 		state = *receiver_state;
 	    else
 		state = erts_atomic32_read_nob(&receiver->state);
-	    if (state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_PENDING_EXIT))
+	    if (state & ERTS_PSFLG_EXITING)
 		goto exiting;
 
             need_locks = receiver_locks & ERTS_PROC_LOCKS_HIGHER_THAN(ERTS_PROC_LOCK_MSGQ);
@@ -414,7 +385,7 @@ queue_messages(Process* receiver,
 
     state = erts_atomic32_read_nob(&receiver->state);
 
-    if (state & (ERTS_PSFLG_PENDING_EXIT|ERTS_PSFLG_EXITING)) {
+    if (state & ERTS_PSFLG_EXITING) {
     exiting:
 	/* Drop message if receiver is exiting or has a pending exit... */
 	if (locked_msgq)
@@ -423,7 +394,7 @@ queue_messages(Process* receiver,
 	return 0;
     }
 
-    res = receiver->msg.len;
+    res = receiver->sig_qs.len;
     if (receiver_locks & ERTS_PROC_LOCK_MAIN) {
 	/*
 	 * We move 'in queue' to 'private queue' and place
@@ -433,8 +404,8 @@ queue_messages(Process* receiver,
 	 * we don't need to include the 'in queue' in
 	 * the root set when garbage collecting.
 	 */
-	res += receiver->msg_inq.len;
-	ERTS_MSGQ_MV_INQ2PRIVQ(receiver);
+	res += receiver->sig_inq.len;
+        erts_proc_sig_fetch(receiver);
         LINK_MESSAGE_PRIVQ(receiver, first, last, len);
     }
     else
@@ -442,38 +413,6 @@ queue_messages(Process* receiver,
 	LINK_MESSAGE(receiver, first, last, len);
     }
 
-    if (IS_TRACED_FL(receiver, F_TRACE_RECEIVE)
-        && (te = &erts_receive_tracing[erts_active_bp_ix()],
-            te->on)) {
-
-        ErtsMessage *msg = first;
-
-#ifdef USE_VM_PROBES
-        if (DTRACE_ENABLED(message_queued)) {
-            DTRACE_CHARBUF(receiver_name, DTRACE_TERM_BUF_SIZE);
-            Sint tok_label = 0;
-            Sint tok_lastcnt = 0;
-            Sint tok_serial = 0;
-            Eterm seq_trace_token = ERL_MESSAGE_TOKEN(msg);
-
-            dtrace_proc_str(receiver, receiver_name);
-            if (seq_trace_token != NIL && is_tuple(seq_trace_token)) {
-                tok_label = signed_val(SEQ_TRACE_T_LABEL(seq_trace_token));
-                tok_lastcnt = signed_val(SEQ_TRACE_T_LASTCNT(seq_trace_token));
-                tok_serial = signed_val(SEQ_TRACE_T_SERIAL(seq_trace_token));
-            }
-            DTRACE6(message_queued,
-                    receiver_name, size_object(ERL_MESSAGE_TERM(msg)),
-                    receiver->msg.len,
-                    tok_label, tok_lastcnt, tok_serial);
-        }
-#endif
-        while (msg) {
-            trace_receive(receiver, from, ERL_MESSAGE_TERM(msg), te);
-            msg = msg->next;
-        }
-
-    }
     if (locked_msgq) {
 	erts_proc_unlock(receiver, ERTS_PROC_LOCK_MSGQ);
     }
@@ -489,8 +428,9 @@ queue_message(Process* receiver,
               ErtsMessage* mp, Eterm msg, Eterm from)
 {
     ERL_MESSAGE_TERM(mp) = msg;
+    ERL_MESSAGE_FROM(mp) = from;
     return queue_messages(receiver, receiver_state, receiver_locks,
-                          mp, &mp->next, 1, from);
+                          mp, &mp->next, 1);
 }
 
 Sint
@@ -503,11 +443,10 @@ erts_queue_message(Process* receiver, ErtsProcLocks receiver_locks,
 
 Sint
 erts_queue_messages(Process* receiver, ErtsProcLocks receiver_locks,
-                    ErtsMessage* first, ErtsMessage** last, Uint len,
-                    Eterm from)
+                    ErtsMessage* first, ErtsMessage** last, Uint len)
 {
     return queue_messages(receiver, NULL, receiver_locks,
-                          first, last, len, from);
+                          first, last, len);
 }
 
 void
@@ -922,70 +861,77 @@ Sint
 erts_move_messages_off_heap(Process *c_p)
 {
     int reds = 1;
+    int i;
+    ErtsMessage *msgq[] = {c_p->sig_qs.first, c_p->sig_qs.cont};
     /*
      * Move all messages off heap. This *only* occurs when the
      * process had off heap message disabled and just enabled
      * it...
      */
-    ErtsMessage *mp;
 
-    reds += c_p->msg.len / 10;
+    reds += c_p->sig_qs.len / 10;
 
     ASSERT(erts_atomic32_read_nob(&c_p->state)
 	   & ERTS_PSFLG_OFF_HEAP_MSGQ);
     ASSERT(c_p->flags & F_OFF_HEAP_MSGQ_CHNG);
 
-    for (mp = c_p->msg.first; mp; mp = mp->next) {
-	Uint msg_sz, token_sz;
+    for (i = 0; i < sizeof(msgq)/sizeof(msgq[0]); i++) {
+        ErtsMessage *mp;
+        for (mp = msgq[i]; mp; mp = mp->next) {
+            Uint msg_sz, token_sz;
 #ifdef USE_VM_PROBES
-	Uint utag_sz;
+            Uint utag_sz;
 #endif
-	Eterm *hp;
-	ErlHeapFragment *hfrag;
+            Eterm *hp;
+            ErlHeapFragment *hfrag;
+
+            if (!ERTS_SIG_IS_INTERNAL_MSG(mp))
+                continue;
 
-	if (mp->data.attached)
-	    continue;
+            if (mp->data.attached)
+                continue;
 
-	if (is_immed(ERL_MESSAGE_TERM(mp))
+            if (is_immed(ERL_MESSAGE_TERM(mp))
 #ifdef USE_VM_PROBES
-	    && is_immed(ERL_MESSAGE_DT_UTAG(mp))
+                && is_immed(ERL_MESSAGE_DT_UTAG(mp))
 #endif
-	    && is_not_immed(ERL_MESSAGE_TOKEN(mp)))
-	    continue;
+                && is_not_immed(ERL_MESSAGE_TOKEN(mp)))
+                continue;
 
-	/*
-	 * The message refers into the heap. Copy the message
-	 * from the heap into a heap fragment and attach
-	 * it to the message...
-	 */
-	msg_sz = size_object(ERL_MESSAGE_TERM(mp));
+            /*
+             * The message refers into the heap. Copy the message
+             * from the heap into a heap fragment and attach
+             * it to the message...
+             */
+            msg_sz = size_object(ERL_MESSAGE_TERM(mp));
 #ifdef USE_VM_PROBES
-	utag_sz = size_object(ERL_MESSAGE_DT_UTAG(mp));
+            utag_sz = size_object(ERL_MESSAGE_DT_UTAG(mp));
 #endif
-	token_sz = size_object(ERL_MESSAGE_TOKEN(mp));
+            token_sz = size_object(ERL_MESSAGE_TOKEN(mp));
 
-	hfrag = new_message_buffer(msg_sz
+            hfrag = new_message_buffer(msg_sz
 #ifdef USE_VM_PROBES
-				   + utag_sz
+                                       + utag_sz
 #endif
-				   + token_sz);
-	hp = hfrag->mem;
-	if (is_not_immed(ERL_MESSAGE_TERM(mp)))
-	    ERL_MESSAGE_TERM(mp) = copy_struct(ERL_MESSAGE_TERM(mp),
-                                               msg_sz, &hp,
-                                               &hfrag->off_heap);
-	if (is_not_immed(ERL_MESSAGE_TOKEN(mp)))
-	    ERL_MESSAGE_TOKEN(mp) = copy_struct(ERL_MESSAGE_TOKEN(mp),
-						token_sz, &hp,
-						&hfrag->off_heap);
+                                       + token_sz);
+            hp = hfrag->mem;
+            if (is_not_immed(ERL_MESSAGE_TERM(mp)))
+                ERL_MESSAGE_TERM(mp) = copy_struct(ERL_MESSAGE_TERM(mp),
+                                                   msg_sz, &hp,
+                                                   &hfrag->off_heap);
+            if (is_not_immed(ERL_MESSAGE_TOKEN(mp)))
+                ERL_MESSAGE_TOKEN(mp) = copy_struct(ERL_MESSAGE_TOKEN(mp),
+                                                    token_sz, &hp,
+                                                    &hfrag->off_heap);
 #ifdef USE_VM_PROBES
-	if (is_not_immed(ERL_MESSAGE_DT_UTAG(mp)))
-	    ERL_MESSAGE_DT_UTAG(mp) = copy_struct(ERL_MESSAGE_DT_UTAG(mp),
-						  utag_sz, &hp,
-						  &hfrag->off_heap);
+            if (is_not_immed(ERL_MESSAGE_DT_UTAG(mp)))
+                ERL_MESSAGE_DT_UTAG(mp) = copy_struct(ERL_MESSAGE_DT_UTAG(mp),
+                                                      utag_sz, &hp,
+                                                      &hfrag->off_heap);
 #endif
-	mp->data.heap_frag = hfrag;
-	reds += 1;
+            mp->data.heap_frag = hfrag;
+            reds += 1;
+        }
     }
 
     return reds;
@@ -1015,7 +961,7 @@ erts_complete_off_heap_message_queue_change(Process *c_p)
     else {
 	reds += 2;
 	erts_proc_lock(c_p, ERTS_PROC_LOCK_MSGQ);
-	ERTS_MSGQ_MV_INQ2PRIVQ(c_p);
+        erts_proc_sig_fetch(c_p);
 	erts_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ);
 	reds += erts_move_messages_off_heap(c_p);
     }
@@ -1225,139 +1171,6 @@ erts_decode_dist_message(Process *proc, ErtsProcLocks proc_locks,
     return 1;
 }
 
-/*
- * ERTS_INSPECT_MSGQ_KEEP_OH_MSGS == 0 will move off heap messages
- * into the heap of the inspected process if off_heap_message_queue
- * is false when process_info(_, messages) is called. That is, the
- * following GC will have more data in the rootset compared to the
- * scenario when process_info(_, messages) had not been called.
- *
- * ERTS_INSPECT_MSGQ_KEEP_OH_MSGS != 0 will keep off heap messages
- * off heap when process_info(_, messages) is called regardless of
- * the off_heap_message_queue setting of the process. That is, it
- * will change the following execution of the process as little as
- * possible.
- */
-#define ERTS_INSPECT_MSGQ_KEEP_OH_MSGS 1
-
-Uint
-erts_prep_msgq_for_inspection(Process *c_p, Process *rp,
-			      ErtsProcLocks rp_locks, ErtsMessageInfo *mip)
-{
-    Uint tot_heap_size;
-    ErtsMessage* mp;
-    Sint i;
-    int self_on_heap;
-    
-    /*
-     * Prepare the message queue for inspection
-     * by process_info().
-     *
-     *
-     * - Decode all messages on external format
-     * - Remove all corrupt dist messages from queue
-     * - Save pointer to, and heap size need of each
-     *   message in the mip array.
-     * - Return total heap size need for all messages
-     *   that needs to be copied.
-     *
-     * If ERTS_INSPECT_MSGQ_KEEP_OH_MSGS == 0:
-     * - In case off heap messages is disabled and
-     *   we are inspecting our own queue, move all
-     *   off heap data into the heap.
-     */
-
-    self_on_heap = c_p == rp && !(c_p->flags & F_OFF_HEAP_MSGQ);
-
-    tot_heap_size = 0;
-    i = 0;
-    mp = rp->msg.first;
-    while (mp) {
-	Eterm msg = ERL_MESSAGE_TERM(mp);
-
-	mip[i].size = 0;
-
-	if (is_non_value(msg)) {
-	    /* Dist message on external format; decode it... */
-	    if (mp->data.attached)
-		erts_decode_dist_message(rp, rp_locks, mp,
-					 ERTS_INSPECT_MSGQ_KEEP_OH_MSGS);
-
-	    msg = ERL_MESSAGE_TERM(mp);
-
-	    if (is_non_value(msg)) {
-		ErtsMessage **mpp;
-		ErtsMessage *bad_mp = mp;
-		/*
-		 * Bad distribution message; remove
-		 * it from the queue...
-		 */
-		ASSERT(!mp->data.attached);
-
-		mpp = i == 0 ? &rp->msg.first : &mip[i-1].msgp->next;
-
-		ASSERT(*mpp == bad_mp);
-
-		erts_msgq_update_internal_pointers(&rp->msg, mpp, &bad_mp->next);
-
-		mp = mp->next;
-		*mpp = mp;
-		rp->msg.len--;
-		bad_mp->next = NULL;
-		erts_cleanup_messages(bad_mp);
-		continue;
-	    }
-	}
-
-	ASSERT(is_value(msg));
-
-#if ERTS_INSPECT_MSGQ_KEEP_OH_MSGS
-	if (is_not_immed(msg) && (!self_on_heap || mp->data.attached)) {
-	    Uint sz = size_object(msg);
-	    mip[i].size = sz;
-	    tot_heap_size += sz;
-	}
-#else
-	if (self_on_heap) {
-	    if (mp->data.attached) {
-		ErtsMessage *tmp = NULL;
-		if (mp->data.attached != ERTS_MSG_COMBINED_HFRAG) {
-		    erts_link_mbuf_to_proc(rp, mp->data.heap_frag);
-		    mp->data.attached = NULL;
-		}
-		else {
-		    /*
-		     * Need to replace the message reference since
-		     * we will get references to the message data
-		     * from the heap...
-		     */
-		    ErtsMessage **mpp;
-		    tmp = erts_alloc_message(0, NULL);
-		    sys_memcpy((void *) tmp->m, (void *) mp->m,
-			       sizeof(Eterm)*ERL_MESSAGE_REF_ARRAY_SZ); 
-		    mpp = i == 0 ? &rp->msg.first : &mip[i-1].msgp->next;
-		    erts_msgq_replace_msg_ref(&rp->msg, tmp, mpp);
-		    erts_save_message_in_proc(rp, mp);
-		    mp = tmp;
-		}
-	    }
-	}
-	else if (is_not_immed(msg)) {
-	    Uint sz = size_object(msg);
-	    mip[i].size = sz;
-	    tot_heap_size += sz;
-	}
-
-#endif
-
-	mip[i].msgp = mp;
-	i++;
-	mp = mp->next;
-    }
-
-    return tot_heap_size;
-}
-
 void erts_factory_proc_init(ErtsHeapFactory* factory,
 			    Process* p)
 {
diff --git a/erts/emulator/beam/erl_message.h b/erts/emulator/beam/erl_message.h
index a14f4f51d8..f56a252aef 100644
--- a/erts/emulator/beam/erl_message.h
+++ b/erts/emulator/beam/erl_message.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1997-2016. All Rights Reserved.
+ * Copyright Ericsson AB 1997-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,6 +21,11 @@
 #ifndef __ERL_MESSAGE_H__
 #define __ERL_MESSAGE_H__
 
+#include "sys.h"
+#define ERTS_PROC_SIG_QUEUE_TYPE_ONLY
+#include "erl_proc_sig_queue.h"
+#undef ERTS_PROC_SIG_QUEUE_TYPE_ONLY
+
 struct proc_bin;
 struct external_thing_;
 
@@ -118,15 +123,16 @@ struct erl_heap_fragment {
 };
 
 /* m[0] = message, m[1] = seq trace token */
-#define ERL_MESSAGE_REF_ARRAY_SZ 2
+#define ERL_MESSAGE_REF_ARRAY_SZ 3
 #define ERL_MESSAGE_TERM(mp) ((mp)->m[0])
 #define ERL_MESSAGE_TOKEN(mp) ((mp)->m[1])
+#define ERL_MESSAGE_FROM(mp) ((mp)->m[2])
 
 #ifdef USE_VM_PROBES
 /* m[2] = dynamic trace user tag */
 #undef ERL_MESSAGE_REF_ARRAY_SZ
-#define ERL_MESSAGE_REF_ARRAY_SZ 3
-#define ERL_MESSAGE_DT_UTAG(mp) ((mp)->m[2])
+#define ERL_MESSAGE_REF_ARRAY_SZ 4
+#define ERL_MESSAGE_DT_UTAG(mp) ((mp)->m[3])
 #else
 #endif
 
@@ -157,28 +163,79 @@ struct erl_mesg {
     ErlHeapFragment hfrag;
 };
 
+/*
+ * The ErtsMessage struct is only one special type
+ * of signal. All signal structs have a common
+ * begining and can be differentiated by looking
+ * at the ErtsSignal 'common.tag' field.
+ *
+ * - An ordinary message will have a value
+ * - A distribution message that has not been
+ *   decoded yet will have the non-value.
+ * - Other signals will have an external pid
+ *   header tag. In order to differentiate
+ *   between those signals one needs to look
+ *   at the arity part of the header (see
+ *   erts_proc_sig_queue.h).
+ */
+
+#define ERTS_SIG_IS_NON_MSG_TAG(Tag) \
+    (is_external_pid_header((Tag)))
+
+#define ERTS_SIG_IS_NON_MSG(Sig) \
+    ERTS_SIG_IS_NON_MSG_TAG(((ErtsSignal *) (Sig))->common.tag)
+
+#define ERTS_SIG_IS_INTERNAL_MSG_TAG(Tag) \
+    (!is_header((Tag)))
+#define ERTS_SIG_IS_INTERNAL_MSG(Sig) \
+    ERTS_SIG_IS_INTERNAL_MSG_TAG(((ErtsSignal *) (Sig))->common.tag)
+
+#define ERTS_SIG_IS_EXTERNAL_MSG_TAG(Tag) \
+    ((Tag) == THE_NON_VALUE)
+#define ERTS_SIG_IS_EXTERNAL_MSG(Sig) \
+    ERTS_SIG_IS_EXTERNAL_MSG_TAG(((ErtsSignal *) (Sig))->common.tag)
+
+#define ERTS_SIG_IS_MSG_TAG(Tag) \
+    (!ERTS_SIG_IS_NON_MSG_TAG(Tag))
+#define ERTS_SIG_IS_MSG(Sig) \
+    ERTS_SIG_IS_MSG_TAG(((ErtsSignal *) (Sig))->common.tag)
+
+typedef union {
+    ErtsSignalCommon common;
+    ErtsMessageRef msg;
+} ErtsSignal;
+
+typedef struct {
+    /* pointers to next pointers pointing to... */
+    ErtsMessage **next; /* ... next (non-message) signal */
+    ErtsMessage **last; /* ... next (non-message) signal */
+} ErtsMsgQNMSigs;
+
 /* Size of default message buffer (erl_message.c) */
 #define ERL_MESSAGE_BUF_SZ 500
 
 typedef struct {
-    ErtsMessage* first;
-    ErtsMessage** last;  /* point to the last next pointer */
-    ErtsMessage** save;
-    Sint len;            /* queue length */
+    /* inner queue */
+    ErtsMessage *first;
+    ErtsMessage **last;  /* point to the last next pointer */
+    ErtsMessage **save;
 
-    /*
-     * The following field is used by the recv_mark/1 and
-     * recv_set/1 instructions.
-     */
-    ErtsMessage** saved_last;	/* saved last pointer */
-} ErlMessageQueue;
+    /* middle queue */
+    ErtsMessage *cont;
+    ErtsMessage **cont_last;
+    ErtsMsgQNMSigs nmsigs;
 
+    /* Common for inner and middle queue */
+    ErtsMessage **saved_last;	/* saved last pointer */
+    Sint len; /* message queue length (inner+middle) */
+} ErtsSignalPrivQueues;
 
 typedef struct {
     ErtsMessage* first;
     ErtsMessage** last;  /* point to the last next pointer */
     Sint len;            /* queue length */
-} ErlMessageInQueue;
+    ErtsMsgQNMSigs nmsigs;
+} ErtsSignalInQueue;
 
 typedef struct erl_trace_message_queue__ {
     struct erl_trace_message_queue__ *next; /* point to the next receiver */
@@ -188,9 +245,46 @@ typedef struct erl_trace_message_queue__ {
     Sint len;            /* queue length */
 } ErlTraceMessageQueue;
 
+#define ERTS_RECV_MARK_SAVE(P)                                          \
+    do {                                                                \
+        erts_proc_lock((P), ERTS_PROC_LOCK_MSGQ);                       \
+        if ((P)->sig_inq.first)                                         \
+            erts_proc_sig_fetch((P));                                   \
+        erts_proc_unlock((P), ERTS_PROC_LOCK_MSGQ);                     \
+        if ((P)->sig_qs.cont) {                                         \
+            (P)->sig_qs.saved_last = (P)->sig_qs.cont_last;             \
+            (P)->flags |= F_DEFERRED_SAVED_LAST;                        \
+        }                                                               \
+        else {                                                          \
+            (P)->sig_qs.saved_last = (P)->sig_qs.last;                  \
+            (P)->flags &= ~F_DEFERRED_SAVED_LAST;                       \
+        }                                                               \
+    } while (0)
+
+#define ERTS_RECV_MARK_SET(P)                                           \
+    do {                                                                \
+        if ((P)->sig_qs.saved_last) {                                   \
+            if ((P)->flags & F_DEFERRED_SAVED_LAST) {                   \
+                /* Points to middle queue; use end of inner */          \
+                (P)->sig_qs.save = (P)->sig_qs.last;                    \
+                ASSERT(!PEEK_MESSAGE((P)));                             \
+            }                                                           \
+            else {                                                      \
+                /* Points to inner queue; safe to use */                \
+                (P)->sig_qs.save = (P)->sig_qs.saved_last;              \
+            }                                                           \
+        }                                                               \
+    } while (0)
+
+#define ERTS_RECV_MARK_CLEAR(P)                                         \
+    do {                                                                \
+        (P)->sig_qs.saved_last = NULL;                                  \
+        (P)->flags &= ~F_DEFERRED_SAVED_LAST;                           \
+    } while (0)
+
 
 /* Get "current" message */
-#define PEEK_MESSAGE(p)  (*(p)->msg.save)
+#define PEEK_MESSAGE(p)  (*(p)->sig_qs.save)
 
 #ifdef USE_VM_PROBES
 #define LINK_MESSAGE_DTAG(mp, dt) ERL_MESSAGE_DT_UTAG(mp) = dt
@@ -198,58 +292,69 @@ typedef struct erl_trace_message_queue__ {
 #define LINK_MESSAGE_DTAG(mp, dt)
 #endif
 
-#define LINK_MESSAGE_IMPL(p, first_msg, last_msg, num_msgs, where) do { \
-        *(p)->where.last = (first_msg);                                 \
-        (p)->where.last = (last_msg);                                   \
-        (p)->where.len += (num_msgs);                                   \
-    } while(0)
+#ifdef USE_VM_PROBES
+#  define ERTS_MSG_RECV_TRACED(P)                                       \
+    ((ERTS_TRACE_FLAGS((P)) & F_TRACE_RECEIVE)                          \
+     || DTRACE_ENABLED(message_queued))
+#else
+#  define ERTS_MSG_RECV_TRACED(P)                                       \
+    (ERTS_TRACE_FLAGS((P)) & F_TRACE_RECEIVE)
+
+#endif
 
 
 /* Add message last in private message queue */
-#define LINK_MESSAGE_PRIVQ(p, first_msg, last_msg, len)                 \
+#define LINK_MESSAGE_PRIVQ(p, first_msg, last_msg, num_msgs)            \
     do {                                                                \
-        LINK_MESSAGE_IMPL(p, first_msg, last_msg, len, msg);            \
+        ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE__((p), "before");             \
+        if ((p)->sig_qs.cont || ERTS_MSG_RECV_TRACED((p))) {            \
+            *(p)->sig_qs.cont_last = (first_msg);                       \
+            (p)->sig_qs.cont_last = (last_msg);                         \
+        }                                                               \
+        else {                                                          \
+            *(p)->sig_qs.last = (first_msg);                            \
+            (p)->sig_qs.last = (last_msg);                              \
+        }                                                               \
+        (p)->sig_qs.len += (num_msgs);                                  \
+        ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE__((p), "after");              \
     } while (0)
 
 /* Add message last_msg in message queue */
-#define LINK_MESSAGE(p, first_msg, last_msg, len)       \
-    LINK_MESSAGE_IMPL(p, first_msg, last_msg, len, msg_inq)
-
-#define ERTS_MSGQ_MV_INQ2PRIVQ(p)                   \
-    do {                                                \
-        if (p->msg_inq.first) {                         \
-            *p->msg.last = p->msg_inq.first;            \
-            p->msg.last = p->msg_inq.last;              \
-            p->msg.len += p->msg_inq.len;               \
-            p->msg_inq.first = NULL;                    \
-            p->msg_inq.last = &p->msg_inq.first;        \
-            p->msg_inq.len = 0;                         \
-        }                                               \
-    } while (0)
-
+#define LINK_MESSAGE(p, first_msg, last_msg, num_msgs) \
+    do {                                                                \
+        ERTS_HDBG_CHECK_SIGNAL_IN_QUEUE__((p), "before");               \
+        *(p)->sig_inq.last = (first_msg);                               \
+        (p)->sig_inq.last = (last_msg);                                 \
+        (p)->sig_inq.len += (num_msgs);                                 \
+        ERTS_HDBG_CHECK_SIGNAL_IN_QUEUE__((p), "before");               \
+    } while(0)
 
 /* Unlink current message */
-#define UNLINK_MESSAGE(p,msgp) do { \
-     ErtsMessage* __mp = (msgp)->next; \
-     *(p)->msg.save = __mp; \
-     (p)->msg.len--; \
-     if (__mp == NULL) \
-         (p)->msg.last = (p)->msg.save; \
-} while(0)
+#define UNLINK_MESSAGE(p,msgp)                                          \
+    do {                                                                \
+        ErtsMessage *mp__ = (msgp)->next;                               \
+        ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE__((p), "before");             \
+        *(p)->sig_qs.save = mp__;                                       \
+        (p)->sig_qs.len--;                                              \
+        if (mp__ == NULL)                                               \
+            (p)->sig_qs.last = (p)->sig_qs.save;                        \
+        ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE__((p), "after");              \
+    } while(0)
 
 /*
  * Reset message save point (after receive match).
  * Also invalidate the saved position since it may no
  * longer be safe to use.
  */
-#define JOIN_MESSAGE(p) do {                    \
-    (p)->msg.save = &(p)->msg.first;            \
-    (p)->msg.saved_last = 0;                    \
-} while(0)
+#define JOIN_MESSAGE(p)                                                 \
+   do {                                                                 \
+       (p)->sig_qs.save = &(p)->sig_qs.first;                           \
+       ERTS_RECV_MARK_CLEAR((p));                                       \
+   } while(0)
 
 /* Save current message */
 #define SAVE_MESSAGE(p) \
-     (p)->msg.save = &(*(p)->msg.save)->next
+     (p)->sig_qs.save = &(*(p)->sig_qs.save)->next
 
 #define ERTS_SND_FLG_NO_SEQ_TRACE		(((unsigned) 1) << 0)
 
@@ -276,6 +381,7 @@ typedef struct erl_trace_message_queue__ {
         (MP)->next = NULL;                              \
         ERL_MESSAGE_TERM(MP) = THE_NON_VALUE;           \
         ERL_MESSAGE_TOKEN(MP) = NIL;                    \
+        ERL_MESSAGE_FROM(MP) = NIL;                     \
         ERL_MESSAGE_DT_UTAG_INIT(MP);                   \
         MP->data.attached = NULL;                       \
     } while (0)
@@ -288,7 +394,7 @@ void free_message_buffer(ErlHeapFragment *);
 void erts_queue_dist_message(Process*, ErtsProcLocks, ErtsDistExternal *, Eterm, Eterm);
 Sint erts_queue_message(Process*, ErtsProcLocks,ErtsMessage*, Eterm, Eterm);
 Sint erts_queue_messages(Process*, ErtsProcLocks,
-                         ErtsMessage*, ErtsMessage**, Uint, Eterm);
+                         ErtsMessage*, ErtsMessage**, Uint);
 void erts_deliver_exit_message(Eterm, Process*, ErtsProcLocks *, Eterm, Eterm);
 Sint erts_send_message(Process*, Process*, ErtsProcLocks*, Eterm, unsigned);
 void erts_link_mbuf_to_proc(Process *proc, ErlHeapFragment *bp);
@@ -305,16 +411,6 @@ int erts_decode_dist_message(Process *, ErtsProcLocks, ErtsMessage *, int);
 
 void erts_cleanup_messages(ErtsMessage *mp);
 
-typedef struct {
-    Uint size;
-    ErtsMessage *msgp;
-} ErtsMessageInfo;
-
-Uint erts_prep_msgq_for_inspection(Process *c_p,
-				   Process *rp,
-				   ErtsProcLocks rp_locks,
-				   ErtsMessageInfo *mip);
-
 void *erts_alloc_message_ref(void);
 void erts_free_message_ref(void *);
 
@@ -356,12 +452,6 @@ ERTS_GLB_FORCE_INLINE ErtsMessage *erts_shrink_message(ErtsMessage *mp, Uint sz,
 ERTS_GLB_FORCE_INLINE void erts_free_message(ErtsMessage *mp);
 ERTS_GLB_INLINE Uint erts_used_frag_sz(const ErlHeapFragment*);
 ERTS_GLB_INLINE Uint erts_msg_attached_data_size(ErtsMessage *msg);
-ERTS_GLB_INLINE void erts_msgq_update_internal_pointers(ErlMessageQueue *msgq,
-							ErtsMessage **newpp,
-							ErtsMessage **oldpp);
-ERTS_GLB_INLINE void erts_msgq_replace_msg_ref(ErlMessageQueue *msgq,
-					       ErtsMessage *newp,
-					       ErtsMessage **oldpp);
 
 #define ERTS_MSG_COMBINED_HFRAG ((void *) 0x1)
 
@@ -465,28 +555,6 @@ ERTS_GLB_INLINE Uint erts_msg_attached_data_size(ErtsMessage *msg)
     }
 }
 
-ERTS_GLB_INLINE void
-erts_msgq_update_internal_pointers(ErlMessageQueue *msgq,
-				   ErtsMessage **newpp,
-				   ErtsMessage **oldpp)
-{
-    if (msgq->save == oldpp)
-	msgq->save = newpp;
-    if (msgq->last == oldpp)
-	msgq->last = newpp;
-    if (msgq->saved_last == oldpp)
-	msgq->saved_last = newpp;
-}
-
-ERTS_GLB_INLINE void
-erts_msgq_replace_msg_ref(ErlMessageQueue *msgq, ErtsMessage *newp, ErtsMessage **oldpp)
-{
-    ErtsMessage *oldp = *oldpp;
-    newp->next = oldp->next;
-    erts_msgq_update_internal_pointers(msgq, &newp->next, &oldp->next);
-    *oldpp = newp;
-}
-
 #endif
 
 Uint erts_mbuf_size(Process *p);
@@ -500,4 +568,17 @@ Uint erts_mbuf_size(Process *p);
 #  define ERTS_CHK_MBUF_SZ(P) ((void) 1)
 #endif
 
+#define ERTS_FOREACH_SIG_PRIVQS(PROC, MVAR, CODE)                       \
+    do {                                                                \
+        int i__;                                                        \
+        ErtsMessage *msgs__[] = {(PROC)->sig_qs.first,                  \
+                                 (PROC)->sig_qs.cont};                  \
+        for (i__ = 0; i__ < sizeof(msgs__)/sizeof(msgs__[0]); i__++) {  \
+            ErtsMessage *MVAR;                                          \
+            for (MVAR = msgs__[i__]; MVAR; MVAR = MVAR->next) {         \
+                CODE;                                                   \
+            }                                                           \
+        }                                                               \
+    } while (0)
+
 #endif
diff --git a/erts/emulator/beam/erl_monitor_link.c b/erts/emulator/beam/erl_monitor_link.c
new file mode 100644
index 0000000000..70f36fb6b7
--- /dev/null
+++ b/erts/emulator/beam/erl_monitor_link.c
@@ -0,0 +1,1341 @@
+/*
+ * %CopyrightBegin%
+ * 
+ * Copyright Ericsson AB 2018. All Rights Reserved.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * 
+ * %CopyrightEnd%
+ */
+
+/*
+ * Description:	Monitor and link implementation.
+ *
+ * Author: 	Rickard Green
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include "sys.h"
+#include <stddef.h>
+#include "global.h"
+#include "erl_node_tables.h"
+#include "erl_monitor_link.h"
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
+ * Red-black tree implementation used for monitors and links.                *
+\*                                                                           */
+
+static ERTS_INLINE Eterm
+ml_get_key(ErtsMonLnkNode *mln)
+{
+    char *ptr = (char *) mln;
+    ptr += mln->key_offset;
+
+#ifdef ERTS_ML_DEBUG
+    switch (mln->type) {
+    case ERTS_MON_TYPE_PROC:
+    case ERTS_MON_TYPE_PORT:
+    case ERTS_MON_TYPE_DIST_PROC:
+    case ERTS_MON_TYPE_TIME_OFFSET:
+    case ERTS_MON_TYPE_RESOURCE: {
+        ErtsMonitorData *mdp = erts_monitor_to_data(mln);
+        ERTS_ML_ASSERT(&mdp->ref == (Eterm *) ptr);
+        break;
+    }
+    case ERTS_LNK_TYPE_PROC:
+    case ERTS_LNK_TYPE_DIST_PROC:
+    case ERTS_LNK_TYPE_PORT:
+    case ERTS_MON_TYPE_NODE:
+    case ERTS_MON_TYPE_NODES:
+    case ERTS_MON_TYPE_SUSPEND:
+        ERTS_ML_ASSERT(&mln->other.item == (Eterm *) ptr);
+        break;
+    default:
+        ERTS_INTERNAL_ERROR("Invalid type");
+        break;
+    }
+#endif
+
+    return *((Eterm *) ptr);
+}
+
+/*
+ * Comparison functions for valid *and only valid* keys. That
+ * is, if the set of valid keys is changed, this function needs
+ * to be updated...
+ *
+ * Note that this function does *not* order terms according to
+ * term order, and that the order may vary between emulator
+ * restarts...
+ */
+static int
+ml_cmp_keys(Eterm key1, Eterm key2)
+{
+    /*
+     * A monitor key is either an internal pid, a (nodename) atom,
+     * a small (monitor nodes bitmask), an ordinary internal ref,
+     * or an external ref.
+     *
+     * Order between monitors with keys of different types:
+     *  internal pid < atom < small < internal ref < external ref
+     *
+     * A link key is either a pid, an internal port
+     *
+     * Order between links with keys of different types:
+     *  internal pid < internal port < external pid
+     *
+     */
+    ERTS_ML_ASSERT(is_internal_pid(key1)
+                   || is_internal_port(key1)
+                   || is_atom(key1)
+                   || is_small(key1)
+                   || is_external_pid(key1)
+                   || is_internal_ordinary_ref(key1)
+                   || is_external_ref(key1));
+
+    ERTS_ML_ASSERT(is_internal_pid(key2)
+                   || is_internal_port(key2)
+                   || is_atom(key2)
+                   || is_small(key2)
+                   || is_external_pid(key2)
+                   || is_internal_ordinary_ref(key2)
+                   || is_external_ref(key2));
+
+    if (is_immed(key1)) {
+        int key1_tag, key2_tag;
+
+        ERTS_ML_ASSERT(is_internal_pid(key1)
+                       || is_internal_port(key1)
+                       || is_atom(key1)
+                       || is_small(key1));
+
+        if (key1 == key2)
+            return 0;
+
+        if (is_boxed(key2))
+            return -1;
+
+        ERTS_ML_ASSERT(is_internal_pid(key2)
+                       || is_internal_port(key2)
+                       || is_atom(key2)
+                       || is_small(key2));
+
+        key1_tag = (int) (key1 & _TAG_IMMED1_MASK);
+        key2_tag = (int) (key2 & _TAG_IMMED1_MASK);
+
+        if (key1_tag != key2_tag)
+            return key1_tag - key2_tag;
+
+        ASSERT((is_atom(key1) && is_atom(key2))
+               || (is_small(key1) && is_small(key2))
+               || (is_internal_pid(key1) && is_internal_pid(key2))
+               || (is_internal_port(key1) && is_internal_port(key2)));
+
+        return key1 < key2 ? -1 : 1;
+    }
+    else {
+        Eterm *w1, hdr1;
+
+        ERTS_ML_ASSERT(is_boxed(key1));
+
+        w1 = boxed_val(key1);
+        hdr1 = *w1;
+
+        if ((hdr1 & _TAG_HEADER_MASK) == _TAG_HEADER_REF) {
+            Eterm *w2;
+
+            if (!is_internal_ref(key2))
+                return is_immed(key2) ? 1 : -1;
+
+            w2 = internal_ref_val(key2);
+
+            ERTS_ML_ASSERT(w1[0] == ERTS_REF_THING_HEADER);
+            ERTS_ML_ASSERT(w2[0] == ERTS_REF_THING_HEADER);
+
+            return sys_memcmp((void *) &w1[1], (void *) &w2[1],
+                              (ERTS_REF_THING_SIZE - 1)*sizeof(Eterm));
+        }
+
+        ERTS_ML_ASSERT(is_external(key1));
+
+        if (is_not_external(key2))
+            return 1;
+        else {
+            Uint ndw1, ndw2;
+            ExternalThing *et1, *et2;
+            ErlNode *n1, *n2;
+
+            ERTS_ML_ASSERT((is_external_ref(key1) && is_external_ref(key2))
+                           || (is_external_pid(key1) && is_external_pid(key2)));
+
+            et1 = (ExternalThing *) w1;
+            et2 = (ExternalThing *) external_val(key2);
+
+            n1 = et1->node;
+            n2 = et2->node;
+
+            if (n1 != n2) {
+                if (n1->sysname != n2->sysname)
+                    return n1->sysname < n2->sysname ? -1 : 1;
+                ASSERT(n1->creation != n2->creation);
+                return n1->creation < n2->creation ? -1 : 1;
+            }
+
+            ndw1 = external_thing_data_words(et1);
+            ndw2 = external_thing_data_words(et1);
+            if (ndw1 != ndw2)
+                return ndw1 < ndw2 ? -1 : 1;
+
+            return sys_memcmp((void *) &et1->data.ui[0],
+                              (void *) &et2->data.ui[0],
+                              ndw1*sizeof(Eterm));
+        }
+    }
+}
+
+#define ERTS_ML_TPFLG_RED               (((UWord) 1) << 0)
+
+#define ERTS_ML_TPFLGS_MASK             (ERTS_ML_TPFLG_RED)
+
+#define ERTS_RBT_PREFIX mon_lnk
+#define ERTS_RBT_T ErtsMonLnkNode
+#define ERTS_RBT_KEY_T Eterm
+#define ERTS_RBT_FLAGS_T UWord
+#define ERTS_RBT_INIT_EMPTY_TNODE(T)					\
+    do {								\
+	(T)->node.tree.parent = (UWord) NULL;                           \
+	(T)->node.tree.right = NULL;                                    \
+	(T)->node.tree.left = NULL;                                     \
+    } while (0)
+#define ERTS_RBT_IS_RED(T)						\
+    (!!((T)->node.tree.parent & ERTS_ML_TPFLG_RED))
+#define ERTS_RBT_SET_RED(T)						\
+    ((T)->node.tree.parent |= ERTS_ML_TPFLG_RED)
+#define ERTS_RBT_IS_BLACK(T)						\
+    (!ERTS_RBT_IS_RED((T)))
+#define ERTS_RBT_SET_BLACK(T)						\
+    ((T)->node.tree.parent &= ~ERTS_ML_TPFLG_RED)
+#define ERTS_RBT_GET_FLAGS(T)						\
+    ((T)->node.tree.parent & ERTS_ML_TPFLGS_MASK)
+#define ERTS_RBT_SET_FLAGS(T, F)					\
+    do {								\
+	ERTS_ML_ASSERT((((UWord) (F)) & ~ERTS_ML_TPFLGS_MASK) == 0);	\
+	(T)->node.tree.parent &= ~ERTS_ML_TPFLGS_MASK;                 \
+	(T)->node.tree.parent |= (F);                                   \
+    } while (0)
+#define ERTS_RBT_GET_PARENT(T)						\
+    ((ERTS_RBT_T *) ((T)->node.tree.parent & ~ERTS_ML_TPFLGS_MASK))
+#define ERTS_RBT_SET_PARENT(T, P)					\
+    do {								\
+	ERTS_ML_ASSERT((((UWord) (P)) & ERTS_ML_TPFLGS_MASK) == 0);	\
+	(T)->node.tree.parent &= ERTS_ML_TPFLGS_MASK;                  \
+	(T)->node.tree.parent |= (UWord) (P);                           \
+    } while (0)
+#define ERTS_RBT_GET_RIGHT(T) ((T)->node.tree.right)
+#define ERTS_RBT_SET_RIGHT(T, R) ((T)->node.tree.right = (R))
+#define ERTS_RBT_GET_LEFT(T) ((T)->node.tree.left)
+#define ERTS_RBT_SET_LEFT(T, L) ((T)->node.tree.left = (L))
+#define ERTS_RBT_GET_KEY(T) (ml_get_key((T)))
+#define ERTS_RBT_CMP_KEYS(KX, KY) (ml_cmp_keys((KX), (KY)))
+#define ERTS_RBT_WANT_DELETE
+#define ERTS_RBT_WANT_LOOKUP
+#define ERTS_RBT_WANT_LOOKUP_INSERT
+#define ERTS_RBT_WANT_LOOKUP_CREATE
+#define ERTS_RBT_WANT_INSERT
+#define ERTS_RBT_WANT_REPLACE
+#define ERTS_RBT_WANT_FOREACH
+#define ERTS_RBT_WANT_FOREACH_YIELDING
+#define ERTS_RBT_WANT_FOREACH_DESTROY
+#define ERTS_RBT_WANT_FOREACH_DESTROY_YIELDING
+#define ERTS_RBT_UNDEF
+
+#include "erl_rbtree.h"
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
+ * Tree Operations                                                           *
+\*                                                                           */
+
+static ErtsMonLnkNode *
+ml_rbt_lookup(ErtsMonLnkNode *root, Eterm ref)
+{
+    ErtsMonLnkNode *ml = mon_lnk_rbt_lookup(root, ref);
+    ASSERT(!ml || (ml->flags & ERTS_ML_FLG_IN_TABLE));
+    return ml;
+}
+
+static ErtsMonLnkNode *
+ml_rbt_lookup_insert(ErtsMonLnkNode **root, ErtsMonLnkNode *ml)
+{
+    ErtsMonLnkNode *res;
+    ERTS_ML_ASSERT(!(ml->flags & ERTS_ML_FLG_IN_TABLE));
+    res = mon_lnk_rbt_lookup_insert(root, ml);
+    if (!res)
+        ml->flags |= ERTS_ML_FLG_IN_TABLE;
+    return res;
+}
+
+static ErtsMonLnkNode *
+ml_rbt_lookup_create(ErtsMonLnkNode ** root, Eterm key,
+                     ErtsMonLnkNode *(*create)(Eterm, void *),
+                     void *carg, int *created)
+{
+    ErtsMonLnkNode *ml;
+    ml = mon_lnk_rbt_lookup_create(root, key, create, carg, created);
+    if (*created)
+        ml->flags |= ERTS_ML_FLG_IN_TABLE;
+    return ml;
+}
+
+static void
+ml_rbt_insert(ErtsMonLnkNode **root, ErtsMonLnkNode *ml)
+{
+#ifdef ERTS_ML_DEBUG
+    ErtsMonLnkNode *res;
+    ERTS_ML_ASSERT(!(ml->flags & ERTS_ML_FLG_IN_TABLE));
+    res = ml_rbt_lookup(*root, ml_get_key(ml));
+    ERTS_ML_ASSERT(res == NULL);
+#endif
+
+    mon_lnk_rbt_insert(root, ml);
+    ml->flags |= ERTS_ML_FLG_IN_TABLE;
+}
+
+static void
+ml_rbt_replace(ErtsMonLnkNode **root, ErtsMonLnkNode *old, ErtsMonLnkNode *new)
+{
+    ERTS_ML_ASSERT(old->flags & ERTS_ML_FLG_IN_TABLE);
+    ERTS_ML_ASSERT(!(new->flags & ERTS_ML_FLG_IN_TABLE));
+
+    mon_lnk_rbt_replace(root, old, new);
+    old->flags &= ~ERTS_ML_FLG_IN_TABLE;
+    new->flags |= ERTS_ML_FLG_IN_TABLE;
+}
+
+static void
+ml_rbt_delete(ErtsMonLnkNode **root, ErtsMonLnkNode *ml)
+{
+    ERTS_ML_ASSERT(ml->flags & ERTS_ML_FLG_IN_TABLE);
+    mon_lnk_rbt_delete(root, ml);
+    ml->flags &= ~ERTS_ML_FLG_IN_TABLE;
+}
+
+
+static void
+ml_rbt_foreach(ErtsMonLnkNode *root,
+               void (*func)(ErtsMonLnkNode *, void *),
+               void *arg)
+{
+    mon_lnk_rbt_foreach(root, func, arg);
+}
+
+typedef struct {
+    ErtsMonLnkNode *root;
+    mon_lnk_rbt_yield_state_t rbt_ystate;
+} ErtsMonLnkYieldState;
+
+static int
+ml_rbt_foreach_yielding(ErtsMonLnkNode *root,
+                        void (*func)(ErtsMonLnkNode *, void *),
+                        void *arg,
+                        void **vyspp,
+                        Sint limit)
+{
+    int res;
+    ErtsMonLnkYieldState ys = {root, ERTS_RBT_YIELD_STAT_INITER};
+    ErtsMonLnkYieldState *ysp;
+
+    ysp = (ErtsMonLnkYieldState *) *vyspp;
+    if (!ysp)
+	ysp = &ys;
+    res = mon_lnk_rbt_foreach_yielding(ysp->root, func, arg,
+                                       &ysp->rbt_ystate, limit);
+    if (res == 0) {
+	if (ysp != &ys)
+	    erts_free(ERTS_ALC_T_ML_YIELD_STATE, ysp);
+	*vyspp = NULL;
+    }
+    else {
+
+	if (ysp == &ys) {
+	    ysp = erts_alloc(ERTS_ALC_T_ML_YIELD_STATE,
+			     sizeof(ErtsMonLnkYieldState));
+	    sys_memcpy((void *) ysp, (void *) &ys,
+		       sizeof(ErtsMonLnkYieldState));
+	}
+
+	*vyspp = (void *) ysp;
+    }
+
+    return res;
+}
+
+typedef struct {
+    void (*func)(ErtsMonLnkNode *, void *);
+    void *arg;
+} ErtsMonLnkForeachDeleteContext;
+
+static void
+rbt_wrap_foreach_delete(ErtsMonLnkNode *ml, void *vctxt)
+{
+    ErtsMonLnkForeachDeleteContext *ctxt = vctxt;
+    ERTS_ML_ASSERT(ml->flags & ERTS_ML_FLG_IN_TABLE);
+    ml->flags &= ~ERTS_ML_FLG_IN_TABLE;
+    ctxt->func(ml, ctxt->arg);
+}
+
+static void
+ml_rbt_foreach_delete(ErtsMonLnkNode **root,
+                      void (*func)(ErtsMonLnkNode *, void *),
+                      void *arg)
+{
+    ErtsMonLnkForeachDeleteContext ctxt;
+    ctxt.func = func;
+    ctxt.arg = arg;
+    mon_lnk_rbt_foreach_destroy(root,
+                                rbt_wrap_foreach_delete,
+                                (void *) &ctxt);
+}
+
+static int
+ml_rbt_foreach_delete_yielding(ErtsMonLnkNode **root,
+                               void (*func)(ErtsMonLnkNode *, void *),
+                               void *arg,
+                               void **vyspp,
+                               Sint limit)
+{
+    int res;
+    ErtsMonLnkYieldState ys = {*root, ERTS_RBT_YIELD_STAT_INITER};
+    ErtsMonLnkYieldState *ysp;
+    ErtsMonLnkForeachDeleteContext ctxt;
+    ctxt.func = func;
+    ctxt.arg = arg;
+
+    ysp = (ErtsMonLnkYieldState *) *vyspp;
+    if (!ysp) {
+        *root = NULL;
+	ysp = &ys;
+    }
+    res = mon_lnk_rbt_foreach_destroy_yielding(&ysp->root,
+                                               rbt_wrap_foreach_delete,
+                                               (void *) &ctxt,
+                                               &ysp->rbt_ystate,
+                                               limit);
+    if (res == 0) {
+	if (ysp != &ys)
+	    erts_free(ERTS_ALC_T_ML_YIELD_STATE, ysp);
+	*vyspp = NULL;
+    }
+    else {
+
+	if (ysp == &ys) {
+	    ysp = erts_alloc(ERTS_ALC_T_ML_YIELD_STATE,
+			     sizeof(ErtsMonLnkYieldState));
+	    sys_memcpy((void *) ysp, (void *) &ys,
+		       sizeof(ErtsMonLnkYieldState));
+	}
+
+	*vyspp = (void *) ysp;
+    }
+
+    return res;
+}
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
+ * List Operations                                                           *
+\*                                                                           */
+
+static int
+ml_dl_list_foreach_yielding(ErtsMonLnkNode *list,
+                            void (*func)(ErtsMonLnkNode *, void *),
+                            void *arg,
+                            void **vyspp,
+                            Sint limit)
+{
+    Sint cnt = 0;
+    ErtsMonLnkNode *ml = (ErtsMonLnkNode *) *vyspp;
+
+    ERTS_ML_ASSERT(!ml || list);
+
+    if (!ml)
+        ml = list;
+
+    if (ml) {
+        do {
+            ERTS_ML_ASSERT(ml->flags & ERTS_ML_FLG_IN_TABLE);
+            func(ml, arg);
+            ml = ml->node.list.next;
+            cnt++;
+        } while (ml != list && cnt < limit);
+        if (ml != list) {
+            *vyspp = (void *) ml;
+            return 1; /* yield */
+        }
+    }
+
+    *vyspp = NULL;
+    return 0; /* done */
+}
+
+static int
+ml_dl_list_foreach_delete_yielding(ErtsMonLnkNode **list,
+                                   void (*func)(ErtsMonLnkNode *, void *),
+                                   void *arg,
+                                   void **vyspp,
+                                   Sint limit)
+{
+    Sint cnt = 0;
+    ErtsMonLnkNode *first = *list;
+    ErtsMonLnkNode *ml = (ErtsMonLnkNode *) *vyspp;
+
+    ERTS_ML_ASSERT(!ml || first);
+
+    if (!ml)
+        ml = first;
+
+    if (ml) {
+        do {
+            ErtsMonLnkNode *next = ml->node.list.next;
+            ERTS_ML_ASSERT(ml->flags & ERTS_ML_FLG_IN_TABLE);
+            ml->flags &= ~ERTS_ML_FLG_IN_TABLE;
+            func(ml, arg);
+            ml = next;
+            cnt++;
+        } while (ml != first && cnt < limit);
+        if (ml != first) {
+            *vyspp = (void *) ml;
+            return 1; /* yield */
+        }
+    }
+
+    *vyspp = NULL;
+    *list = NULL;
+    return 0; /* done */
+}
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
+ * Misc                                                                      *
+\*                                                                           */
+
+ErtsMonLnkDist *
+erts_mon_link_dist_create(Eterm nodename)
+{
+    ErtsMonLnkDist *mld = erts_alloc(ERTS_ALC_T_ML_DIST,
+                                     sizeof(ErtsMonLnkDist));
+    mld->nodename = nodename;
+    mld->connection_id = ~((Uint32) 0);
+    erts_atomic_init_nob(&mld->refc, 1);
+    erts_mtx_init(&mld->mtx, "dist_entry_links", nodename,
+                  ERTS_LOCK_FLAGS_CATEGORY_DISTRIBUTION);
+    mld->alive = !0;
+    mld->links = NULL;
+    mld->monitors = NULL;
+    mld->orig_name_monitors = NULL;
+    return mld;
+}
+
+void
+erts_mon_link_dist_destroy__(ErtsMonLnkDist *mld)
+{
+    ERTS_ML_ASSERT(erts_atomic_read_nob(&mld->refc) == 0);
+    ERTS_ML_ASSERT(!mld->alive);
+    ERTS_ML_ASSERT(!mld->links);
+    ERTS_ML_ASSERT(!mld->monitors);
+    ERTS_ML_ASSERT(!mld->orig_name_monitors);
+
+    erts_mtx_destroy(&mld->mtx);
+    erts_free(ERTS_ALC_T_ML_DIST, mld);
+}
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
+ * Monitor Operations                                                        *
+\*                                                                           */
+
+#ifdef ERTS_ML_DEBUG
+size_t erts_monitor_origin_offset;
+size_t erts_monitor_origin_key_offset;
+size_t erts_monitor_target_offset;
+size_t erts_monitor_target_key_offset;
+size_t erts_monitor_node_key_offset;
+#endif
+
+static ERTS_INLINE void
+monitor_init(void)
+{
+#ifdef ERTS_ML_DEBUG
+    erts_monitor_origin_offset = offsetof(ErtsMonitorData, origin);
+    erts_monitor_origin_key_offset = offsetof(ErtsMonitorData, ref);
+    ASSERT(erts_monitor_origin_key_offset >= erts_monitor_origin_offset);
+    erts_monitor_origin_key_offset -= erts_monitor_origin_offset;
+    erts_monitor_target_offset = offsetof(ErtsMonitorData, target);
+    erts_monitor_target_key_offset = offsetof(ErtsMonitorData, ref);
+    ASSERT(erts_monitor_target_key_offset >= erts_monitor_target_offset);
+    erts_monitor_target_key_offset -= erts_monitor_target_offset;
+    erts_monitor_node_key_offset = offsetof(ErtsMonitor, other.item);
+#endif
+}
+
+ErtsMonitor *
+erts_monitor_tree_lookup(ErtsMonitor *root, Eterm key)
+{
+    ERTS_ML_ASSERT(is_internal_ordinary_ref(key)
+                   || is_external_ref(key)
+                   || is_atom(key)
+                   || is_small(key)
+                   || is_internal_pid(key));
+    return (ErtsMonitor *) ml_rbt_lookup((ErtsMonLnkNode *) root, key);
+}
+
+ErtsMonitor *
+erts_monotor_tree_lookup_insert(ErtsMonitor **root, ErtsMonitor *mon)
+{
+    return (ErtsMonitor *) ml_rbt_lookup_insert((ErtsMonLnkNode **) root,
+                                                (ErtsMonLnkNode *) mon);
+}
+
+typedef struct {
+    Uint16 type;
+    Eterm origin;
+} ErtsMonitorCreateCtxt;
+
+static ErtsMonLnkNode *
+create_monitor(Eterm target, void *vcctxt)
+{
+    ErtsMonitorCreateCtxt *cctxt = vcctxt;
+    ErtsMonitorData *mdp = erts_monitor_create(cctxt->type,
+                                               NIL,
+                                               cctxt->origin,
+                                               target,
+                                               NIL);
+    ERTS_ML_ASSERT(ml_cmp_keys(ml_get_key(&mdp->origin), target) == 0);
+    return (ErtsMonLnkNode *) &mdp->origin;
+}
+
+ErtsMonitor *
+erts_monitor_tree_lookup_create(ErtsMonitor **root, int *created, Uint16 type,
+                                Eterm origin, Eterm target)
+{
+    ErtsMonitor *res;
+    ErtsMonitorCreateCtxt cctxt = {type, origin};
+
+    ERTS_ML_ASSERT(type == ERTS_MON_TYPE_NODE || type == ERTS_MON_TYPE_NODES);
+
+    res = (ErtsMonitor *) ml_rbt_lookup_create((ErtsMonLnkNode **) root,
+                                               target, create_monitor,
+                                               (void *) &cctxt,
+                                               created);
+
+    ERTS_ML_ASSERT(res && erts_monitor_is_origin(res));
+
+    return res;
+}
+
+void
+erts_monitor_tree_insert(ErtsMonitor **root, ErtsMonitor *mon)
+{
+    ml_rbt_insert((ErtsMonLnkNode **) root, (ErtsMonLnkNode *) mon);
+}
+
+void
+erts_monitor_tree_replace(ErtsMonitor **root, ErtsMonitor *old, ErtsMonitor *new)
+{
+    ml_rbt_replace((ErtsMonLnkNode **) root,
+                   (ErtsMonLnkNode *) old,
+                   (ErtsMonLnkNode *) new);
+}
+
+void
+erts_monitor_tree_delete(ErtsMonitor **root, ErtsMonitor *mon)
+{
+    ml_rbt_delete((ErtsMonLnkNode **) root, (ErtsMonLnkNode *) mon);
+}
+
+void
+erts_monitor_tree_foreach(ErtsMonitor *root,
+                          void (*func)(ErtsMonitor *, void *),
+                          void *arg)
+{
+    ml_rbt_foreach((ErtsMonLnkNode *) root,
+                   (void (*)(ErtsMonLnkNode*, void*)) func,
+                   arg);
+}
+
+int
+erts_monitor_tree_foreach_yielding(ErtsMonitor *root,
+                                   void (*func)(ErtsMonitor *, void *),
+                                   void *arg,
+                                   void **vyspp,
+                                   Sint limit)
+{
+    return ml_rbt_foreach_yielding((ErtsMonLnkNode *) root,
+                                   (void (*)(ErtsMonLnkNode*, void*)) func,
+                                   arg, vyspp, limit);
+}
+
+void
+erts_monitor_tree_foreach_delete(ErtsMonitor **root,
+                                 void (*func)(ErtsMonitor *, void *),
+                                 void *arg)
+{
+    ml_rbt_foreach_delete((ErtsMonLnkNode **) root,
+                          (void (*)(ErtsMonLnkNode*, void*)) func,
+                          arg);
+}
+
+int
+erts_monitor_tree_foreach_delete_yielding(ErtsMonitor **root,
+                                          void (*func)(ErtsMonitor *, void *),
+                                          void *arg,
+                                          void **vyspp,
+                                          Sint limit)
+{
+    return ml_rbt_foreach_delete_yielding((ErtsMonLnkNode **) root,
+                                          (void (*)(ErtsMonLnkNode*, void*)) func,
+                                          arg, vyspp, limit);
+}
+
+void
+erts_monitor_list_foreach(ErtsMonitor *list,
+                          void (*func)(ErtsMonitor *, void *),
+                          void *arg)
+{
+    void *ystate = NULL;
+    while (ml_dl_list_foreach_yielding((ErtsMonLnkNode *) list,
+                                       (void (*)(ErtsMonLnkNode *, void *)) func,
+                                       arg, &ystate, (Sint) INT_MAX));
+}
+
+int
+erts_monitor_list_foreach_yielding(ErtsMonitor *list,
+                                   void (*func)(ErtsMonitor *, void *),
+                                   void *arg,
+                                   void **vyspp,
+                                   Sint limit)
+{
+    return ml_dl_list_foreach_yielding((ErtsMonLnkNode *) list,
+                                       (void (*)(ErtsMonLnkNode *, void *)) func,
+                                       arg, vyspp, limit);
+}
+
+void
+erts_monitor_list_foreach_delete(ErtsMonitor **list,
+                                 void (*func)(ErtsMonitor *, void *),
+                                 void *arg)
+{
+    void *ystate = NULL;
+    while (ml_dl_list_foreach_delete_yielding((ErtsMonLnkNode **) list,
+                                              (void (*)(ErtsMonLnkNode*, void*)) func,
+                                              arg, &ystate, (Sint) INT_MAX));
+}
+
+int
+erts_monitor_list_foreach_delete_yielding(ErtsMonitor **list,
+                                          void (*func)(ErtsMonitor *, void *),
+                                          void *arg,
+                                          void **vyspp,
+                                          Sint limit)
+{
+    return ml_dl_list_foreach_delete_yielding((ErtsMonLnkNode **) list,
+                                              (void (*)(ErtsMonLnkNode*, void*)) func,
+                                              arg, vyspp, limit);
+}
+
+ErtsMonitorData *
+erts_monitor_create(Uint16 type, Eterm ref, Eterm orgn, Eterm trgt, Eterm name)
+{
+    ErtsMonitorData *mdp;
+
+    switch (type) {
+    case ERTS_MON_TYPE_PROC:
+    case ERTS_MON_TYPE_PORT:
+    case ERTS_MON_TYPE_TIME_OFFSET:
+        if (is_nil(name)) {
+            ErtsMonitorDataHeap *mdhp;
+            ErtsORefThing *ortp;
+
+            ERTS_ML_ASSERT(is_immed(orgn) && is_immed(trgt));
+            ERTS_ML_ASSERT(is_internal_ordinary_ref(ref));
+        
+            mdhp = erts_alloc(ERTS_ALC_T_MONITOR, sizeof(ErtsMonitorDataHeap));
+            mdp = &mdhp->md;
+            ERTS_ML_ASSERT(((void *) mdp) == ((void *) mdhp));
+
+            ortp = (ErtsORefThing *) (char *) internal_ref_val(ref);
+            mdhp->oref_thing = *ortp;
+            mdp->ref = make_internal_ref(&mdhp->oref_thing.header);
+
+            mdp->origin.other.item = trgt;
+            mdp->origin.offset = (Uint16) offsetof(ErtsMonitorData, origin);
+            mdp->origin.key_offset = (Uint16) offsetof(ErtsMonitorData, ref);
+            ERTS_ML_ASSERT(mdp->origin.key_offset >= mdp->origin.offset);
+            mdp->origin.key_offset -= mdp->origin.offset;
+            mdp->origin.flags = (Uint16) 0;
+            mdp->origin.type = type;
+
+            mdp->target.other.item = orgn;
+            mdp->target.offset = (Uint16) offsetof(ErtsMonitorData, target);
+            mdp->target.key_offset = (Uint16) offsetof(ErtsMonitorData, ref);
+            ERTS_ML_ASSERT(mdp->target.key_offset >= mdp->target.offset);
+            mdp->target.key_offset -= mdp->target.offset;
+            mdp->target.flags = ERTS_ML_FLG_TARGET;
+            mdp->target.type = type;
+            break;
+        }
+    case ERTS_MON_TYPE_DIST_PROC:
+    case ERTS_MON_TYPE_RESOURCE:
+    case ERTS_MON_TYPE_NODE:
+    case ERTS_MON_TYPE_NODES: {
+        ErtsMonitorDataExtended *mdep;
+        Uint size = sizeof(ErtsMonitorDataExtended) - sizeof(Eterm);
+        Uint rsz, osz, tsz;
+        Eterm *hp;
+        ErlOffHeap oh;
+        Uint16 name_flag = is_nil(name) ? ((Uint16) 0) : ERTS_ML_FLG_NAME;
+
+        rsz = is_immed(ref) ? 0 : size_object(ref);
+        tsz = is_immed(trgt) ? 0 : size_object(trgt);
+        if (type == ERTS_MON_TYPE_RESOURCE)
+            osz = 0;
+        else
+            osz = is_immed(orgn) ? 0 : size_object(orgn);
+
+        size += (rsz + osz + tsz) * sizeof(Eterm);
+
+        mdep = erts_alloc(ERTS_ALC_T_MONITOR_EXT, size);
+
+        ERTS_INIT_OFF_HEAP(&oh);
+
+        hp = &mdep->heap[0];
+
+        mdp = &mdep->md;
+        ERTS_ML_ASSERT(((void *) mdp) == ((void *) mdep));
+
+        mdp->ref = rsz ? copy_struct(ref, rsz, &hp, &oh) : ref;
+
+        mdp->origin.other.item = tsz ? copy_struct(trgt, tsz, &hp, &oh) : trgt;
+        mdp->origin.offset = (Uint16) offsetof(ErtsMonitorData, origin);
+        mdp->origin.flags = ERTS_ML_FLG_EXTENDED|name_flag;
+        mdp->origin.type = type;
+
+        if (type == ERTS_MON_TYPE_RESOURCE)
+            mdp->target.other.ptr = (void *) orgn;
+        else
+            mdp->target.other.item = osz ? copy_struct(orgn, osz, &hp, &oh) : orgn;
+        mdp->target.offset = (Uint16) offsetof(ErtsMonitorData, target);
+        mdp->target.flags = ERTS_ML_FLG_TARGET|ERTS_ML_FLG_EXTENDED|name_flag;
+        mdp->target.type = type;
+
+        if (type == ERTS_MON_TYPE_NODE || type == ERTS_MON_TYPE_NODES) {
+            mdep->u.refc = 0;
+            mdp->origin.key_offset = (Uint16) offsetof(ErtsMonitor, other.item);
+            mdp->target.key_offset = (Uint16) offsetof(ErtsMonitor, other.item);
+            ERTS_ML_ASSERT(!oh.first);
+            mdep->uptr.node_monitors = NULL;
+        }
+        else {
+            mdep->u.name = name;
+
+            mdp->origin.key_offset = (Uint16) offsetof(ErtsMonitorData, ref);
+            ERTS_ML_ASSERT(mdp->origin.key_offset >= mdp->origin.offset);
+            mdp->origin.key_offset -= mdp->origin.offset;
+
+            mdp->target.key_offset = (Uint16) offsetof(ErtsMonitorData, ref);
+            ERTS_ML_ASSERT(mdp->target.key_offset >= mdp->target.offset);
+            mdp->target.key_offset -= mdp->target.offset;
+
+            mdep->uptr.ohhp = oh.first;
+        }
+        mdep->dist = NULL;
+        break;
+    }
+    case ERTS_MON_TYPE_SUSPEND:
+        ERTS_INTERNAL_ERROR("Use erts_monitor_suspend_create() instead...");
+        mdp = NULL;
+        break;
+    default:
+        ERTS_INTERNAL_ERROR("Invalid monitor type");
+        mdp = NULL;
+        break;
+    }
+
+    erts_atomic32_init_nob(&mdp->refc, 2);
+
+    return mdp;
+}
+
+/*
+ * erts_monitor_destroy__() should only be called from
+ * erts_monitor_release() or erts_monitor_release_both().
+ */
+void
+erts_monitor_destroy__(ErtsMonitorData *mdp)
+{
+    ERTS_ML_ASSERT(erts_atomic32_read_nob(&mdp->refc) == 0);
+    ERTS_ML_ASSERT(!(mdp->origin.flags & ERTS_ML_FLG_IN_TABLE));
+    ERTS_ML_ASSERT(!(mdp->target.flags & ERTS_ML_FLG_IN_TABLE));
+    ERTS_ML_ASSERT((mdp->origin.flags & ERTS_ML_FLGS_SAME)
+                   == (mdp->target.flags & ERTS_ML_FLGS_SAME));
+    ERTS_ML_ASSERT(mdp->origin.type != ERTS_MON_TYPE_SUSPEND);
+
+    if (!(mdp->origin.flags & ERTS_ML_FLG_EXTENDED))
+        erts_free(ERTS_ALC_T_MONITOR, mdp);
+    else {
+        ErtsMonitorDataExtended *mdep = (ErtsMonitorDataExtended *) mdp;
+        ErlOffHeap oh;
+        if (mdp->origin.type == ERTS_MON_TYPE_NODE)
+            ERTS_ML_ASSERT(!mdep->uptr.node_monitors);
+        else if (mdep->uptr.ohhp) {
+            ERTS_INIT_OFF_HEAP(&oh);
+            oh.first = mdep->uptr.ohhp;
+            erts_cleanup_offheap(&oh);
+        }
+        if (mdep->dist)
+            erts_mon_link_dist_dec_refc(mdep->dist);
+        erts_free(ERTS_ALC_T_MONITOR_EXT, mdp);
+    }
+}
+
+void
+erts_monitor_set_dead_dist(ErtsMonitor *mon, Eterm nodename)
+{
+    ErtsMonitorDataExtended *mdep;
+    mdep = (ErtsMonitorDataExtended *) erts_monitor_to_data(mon);
+
+    ERTS_ML_ASSERT(mon->flags & ERTS_ML_FLG_EXTENDED);
+    ERTS_ML_ASSERT(mon->type == ERTS_MON_TYPE_DIST_PROC);
+    ERTS_ML_ASSERT(!mdep->dist);
+
+    mdep->dist = erts_mon_link_dist_create(nodename);
+    mdep->dist->alive = 0;
+}
+
+Uint
+erts_monitor_size(ErtsMonitor *mon)
+{
+    Uint size, refc;
+    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
+
+    ERTS_ML_ASSERT(mon->type != ERTS_MON_TYPE_SUSPEND);
+
+    if (!(mon->flags & ERTS_ML_FLG_EXTENDED))
+        size = sizeof(ErtsMonitorDataHeap);
+    else {
+        ErtsMonitorDataExtended *mdep;
+        Uint hsz = 0;
+
+        mdep = (ErtsMonitorDataExtended *) mdp;
+
+        if (mon->type != ERTS_MON_TYPE_NODE
+            && mon->type != ERTS_MON_TYPE_NODES) {
+            if (!is_immed(mdep->md.ref))
+                hsz += NC_HEAP_SIZE(mdep->md.ref);
+            if (mon->type == ERTS_MON_TYPE_DIST_PROC) {
+                if (!is_immed(mdep->md.origin.other.item))
+                    hsz += NC_HEAP_SIZE(mdep->md.origin.other.item);
+                if (!is_immed(mdep->md.target.other.item))
+                    hsz += NC_HEAP_SIZE(mdep->md.target.other.item);
+            }
+        }
+        size = sizeof(ErtsMonitorDataExtended) + (hsz - 1)*sizeof(Eterm);
+    }
+    
+    refc = (Uint) erts_atomic32_read_nob(&mdp->refc);
+    ASSERT(refc > 0);
+
+    return size / refc;
+}
+
+
+/* suspend monitors... */
+
+ErtsMonitorSuspend *
+erts_monitor_suspend_create(Eterm pid)
+{
+    ErtsMonitorSuspend *msp;
+
+    ERTS_ML_ASSERT(is_internal_pid(pid));
+
+    msp = erts_alloc(ERTS_ALC_T_SUSPEND_MON,
+                     sizeof(ErtsMonitorSuspend));
+    msp->mon.offset = (Uint16) offsetof(ErtsMonitorSuspend, mon);
+    msp->mon.key_offset = (Uint16) offsetof(ErtsMonitor, other.item);
+    msp->mon.other.item = pid;
+    msp->mon.flags = 0;
+    msp->mon.type = ERTS_MON_TYPE_SUSPEND;
+    msp->pending = 0;
+    msp->active = 0;
+    return msp;
+}
+
+static ErtsMonLnkNode *
+create_monitor_suspend(Eterm pid, void *unused)
+{
+    ErtsMonitorSuspend *msp = erts_monitor_suspend_create(pid);
+    return (ErtsMonLnkNode *) &msp->mon;
+}
+
+ErtsMonitorSuspend *
+erts_monitor_suspend_tree_lookup_create(ErtsMonitor **root, int *created,
+                                        Eterm pid)
+{
+    ErtsMonitor *mon;
+    mon = (ErtsMonitor *) ml_rbt_lookup_create((ErtsMonLnkNode **) root,
+                                               pid, create_monitor_suspend,
+                                               NULL,
+                                               created);
+    return erts_monitor_suspend(mon);
+}
+
+void
+erts_monitor_suspend_destroy(ErtsMonitorSuspend *msp)
+{
+    ERTS_ML_ASSERT(!(msp->mon.flags & ERTS_ML_FLG_IN_TABLE));
+    erts_free(ERTS_ALC_T_SUSPEND_MON, msp);
+}
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
+ * Link Operations                                                           *
+ *                                                                           *
+\*                                                                           */
+
+#ifdef ERTS_ML_DEBUG
+size_t erts_link_a_offset;
+size_t erts_link_b_offset;
+size_t erts_link_key_offset;
+#endif
+
+static ERTS_INLINE void
+link_init(void)
+{
+#ifdef ERTS_ML_DEBUG
+    erts_link_a_offset = offsetof(ErtsLinkData, a);
+    erts_link_b_offset = offsetof(ErtsLinkData, b);
+    erts_link_key_offset = offsetof(ErtsLink, other.item);
+#endif
+}
+
+ErtsLink *
+erts_link_tree_lookup(ErtsLink *root, Eterm key)
+{
+    ASSERT(is_pid(key) || is_internal_port(key));
+    return (ErtsLink *) ml_rbt_lookup((ErtsMonLnkNode *) root, key);
+}
+
+ErtsLink *
+erts_link_tree_lookup_insert(ErtsLink **root, ErtsLink *lnk)
+{
+    return (ErtsLink *) ml_rbt_lookup_insert((ErtsMonLnkNode **) root,
+                                             (ErtsMonLnkNode *) lnk);
+}
+
+typedef struct {
+    Uint16 type;
+    Eterm a;
+} ErtsLinkCreateCtxt;
+
+static ErtsMonLnkNode *
+create_link(Eterm b, void *vcctxt)
+{
+    ErtsLinkCreateCtxt *cctxt = vcctxt;
+    ErtsLinkData *ldp = erts_link_create(cctxt->type, cctxt->a, b);
+    ERTS_ML_ASSERT(ml_cmp_keys(ldp->a.other.item, b) == 0);
+    return (ErtsMonLnkNode *) &ldp->a;
+}
+
+ErtsLink *erts_link_tree_lookup_create(ErtsLink **root, int *created,
+                                       Uint16 type, Eterm this,
+                                       Eterm other)
+{
+    ErtsLinkCreateCtxt cctxt;
+    cctxt.type = type;
+    cctxt.a = this;
+    return (ErtsLink *) ml_rbt_lookup_create((ErtsMonLnkNode **) root,
+                                             other, create_link,
+                                             (void *) &cctxt,
+                                             created);
+}
+
+void
+erts_link_tree_insert(ErtsLink **root, ErtsLink *lnk)
+{
+    ml_rbt_insert((ErtsMonLnkNode **) root, (ErtsMonLnkNode *) lnk);
+}
+
+void
+erts_link_tree_replace(ErtsLink **root, ErtsLink *old, ErtsLink *new)
+{
+    ml_rbt_replace((ErtsMonLnkNode **) root,
+                   (ErtsMonLnkNode *) old,
+                   (ErtsMonLnkNode *) new);
+}
+
+void
+erts_link_tree_delete(ErtsLink **root, ErtsLink *lnk)
+{
+    ml_rbt_delete((ErtsMonLnkNode **) root, (ErtsMonLnkNode *) lnk);
+}
+
+void
+erts_link_tree_foreach(ErtsLink *root,
+                       void (*func)(ErtsLink *, void *),
+                       void *arg)
+{
+    ml_rbt_foreach((ErtsMonLnkNode *) root,
+                   (void (*)(ErtsMonLnkNode*, void*)) func,
+                   arg);
+
+}
+
+int
+erts_link_tree_foreach_yielding(ErtsLink *root,
+                                void (*func)(ErtsLink *, void *),
+                                void *arg,
+                                void **vyspp,
+                                Sint limit)
+{
+    return ml_rbt_foreach_yielding((ErtsMonLnkNode *) root,
+                                   (void (*)(ErtsMonLnkNode*, void*)) func,
+                                   arg, vyspp, limit);
+}
+
+void
+erts_link_tree_foreach_delete(ErtsLink **root,
+                              void (*func)(ErtsLink *, void *),
+                              void *arg)
+{
+    ml_rbt_foreach_delete((ErtsMonLnkNode **) root,
+                          (void (*)(ErtsMonLnkNode*, void*)) func,
+                          arg);
+}
+
+int
+erts_link_tree_foreach_delete_yielding(ErtsLink **root,
+                                       void (*func)(ErtsLink *, void *),
+                                       void *arg,
+                                       void **vyspp,
+                                       Sint limit)
+{
+    return ml_rbt_foreach_delete_yielding((ErtsMonLnkNode **) root,
+                                          (void (*)(ErtsMonLnkNode*, void*)) func,
+                                          arg, vyspp, limit);
+}
+
+void
+erts_link_list_foreach(ErtsLink *list,
+                       void (*func)(ErtsLink *, void *),
+                       void *arg)
+{
+    void *ystate = NULL;
+    while (ml_dl_list_foreach_yielding((ErtsMonLnkNode *) list,
+                                       (void (*)(ErtsMonLnkNode *, void *)) func,
+                                       arg, &ystate, (Sint) INT_MAX));
+}
+
+int
+erts_link_list_foreach_yielding(ErtsLink *list,
+                                void (*func)(ErtsLink *, void *),
+                                void *arg,
+                                void **vyspp,
+                                Sint limit)
+{
+    return ml_dl_list_foreach_yielding((ErtsMonLnkNode *) list,
+                                       (void (*)(ErtsMonLnkNode *, void *)) func,
+                                       arg, vyspp, limit);
+}
+
+void
+erts_link_list_foreach_delete(ErtsLink **list,
+                               void (*func)(ErtsLink *, void *),
+                               void *arg)
+{
+    void *ystate = NULL;
+    while (ml_dl_list_foreach_delete_yielding((ErtsMonLnkNode **) list,
+                                              (void (*)(ErtsMonLnkNode*, void*)) func,
+                                              arg, &ystate, (Sint) INT_MAX));
+}
+
+int
+erts_link_list_foreach_delete_yielding(ErtsLink **list,
+                                       void (*func)(ErtsLink *, void *),
+                                       void *arg,
+                                       void **vyspp,
+                                       Sint limit)
+{
+    return ml_dl_list_foreach_delete_yielding((ErtsMonLnkNode **) list,
+                                              (void (*)(ErtsMonLnkNode*, void*)) func,
+                                              arg, vyspp, limit);
+}
+
+ErtsLinkData *
+erts_link_create(Uint16 type, Eterm a, Eterm b)
+{
+    ErtsLinkData *ldp;
+
+#ifdef ERTS_ML_DEBUG
+    switch (type) {
+    case ERTS_LNK_TYPE_PROC:
+        ERTS_ML_ASSERT(is_internal_pid(a) && is_internal_pid(a));
+        break;
+    case ERTS_LNK_TYPE_PORT:
+        ERTS_ML_ASSERT(is_internal_pid(a) || is_internal_pid(b));
+        ERTS_ML_ASSERT(is_internal_port(a) || is_internal_port(b));
+        break;
+    case ERTS_LNK_TYPE_DIST_PROC:
+        ERTS_ML_ASSERT(is_internal_pid(a) || is_internal_pid(b));
+        ERTS_ML_ASSERT(is_external_pid(a) || is_external_pid(b));
+        break;
+    default:
+        ERTS_INTERNAL_ERROR("Invalid link type");
+        break;
+    }
+#endif
+
+    if (type != ERTS_LNK_TYPE_DIST_PROC) {
+        ldp = erts_alloc(ERTS_ALC_T_LINK, sizeof(ErtsLinkData));
+
+        ldp->a.other.item = b;
+        ldp->a.flags = (Uint16) 0;
+
+        ldp->b.other.item = a;
+        ldp->b.flags = (Uint16) 0;
+    }
+    else {
+        ErtsLinkDataExtended *ldep;
+        Uint size, hsz;
+        Eterm *hp;
+        ErlOffHeap oh;
+
+        if (is_internal_pid(a))
+            hsz = NC_HEAP_SIZE(b);
+        else 
+            hsz = NC_HEAP_SIZE(a);
+        ERTS_ML_ASSERT(hsz > 0);
+
+        size = sizeof(ErtsLinkDataExtended) - sizeof(Eterm);
+        size += hsz*sizeof(Eterm);
+
+        ldp = erts_alloc(ERTS_ALC_T_LINK_EXT, size);
+
+        ldp->a.flags = ERTS_ML_FLG_EXTENDED;
+        ldp->b.flags = ERTS_ML_FLG_EXTENDED;
+
+        ldep = (ErtsLinkDataExtended *) ldp;
+        hp = &ldep->heap[0];
+
+        ERTS_INIT_OFF_HEAP(&oh);
+
+        if (is_internal_pid(a)) {
+            ldp->a.other.item = STORE_NC(&hp, &oh, b);
+            ldp->b.other.item = a;
+        }
+        else {
+            ldp->a.other.item = b;
+            ldp->b.other.item = STORE_NC(&hp, &oh, a);
+        }
+
+        ldep->ohhp = oh.first;
+        ldep->dist = NULL;
+    }
+
+    erts_atomic32_init_nob(&ldp->refc, 2);
+
+    ldp->a.key_offset = (Uint16) offsetof(ErtsLink, other.item);
+    ldp->a.offset = (Uint16) offsetof(ErtsLinkData, a);
+    ldp->a.type = type;
+
+    ldp->b.key_offset = (Uint16) offsetof(ErtsLink, other.item);
+    ldp->b.offset = (Uint16) offsetof(ErtsLinkData, b);
+    ldp->b.type = type;
+
+    return ldp;
+}
+
+/*
+ * erts_link_destroy__() should only be called from
+ * erts_link_release() or erts_link_release_both().
+ */
+void
+erts_link_destroy__(ErtsLinkData *ldp)
+{
+    ERTS_ML_ASSERT(erts_atomic32_read_nob(&ldp->refc) == 0);
+    ERTS_ML_ASSERT(!(ldp->a.flags & ERTS_ML_FLG_IN_TABLE));
+    ERTS_ML_ASSERT(!(ldp->b.flags & ERTS_ML_FLG_IN_TABLE));
+    ERTS_ML_ASSERT((ldp->a.flags & ERTS_ML_FLGS_SAME)
+                   == (ldp->b.flags & ERTS_ML_FLGS_SAME));
+
+    if (!(ldp->a.flags & ERTS_ML_FLG_EXTENDED))
+        erts_free(ERTS_ALC_T_LINK, ldp);
+    else {
+        ErtsLinkDataExtended *ldep = (ErtsLinkDataExtended *) ldp;
+        ErlOffHeap oh;
+        if (ldep->ohhp) {
+            ERTS_INIT_OFF_HEAP(&oh);
+            oh.first = ldep->ohhp;
+            erts_cleanup_offheap(&oh);
+        }
+        if (ldep->dist)
+            erts_mon_link_dist_dec_refc(ldep->dist);
+        erts_free(ERTS_ALC_T_LINK_EXT, ldep);
+    }
+}
+
+void
+erts_link_set_dead_dist(ErtsLink *lnk, Eterm nodename)
+{
+    ErtsLinkDataExtended *ldep;
+    ldep = (ErtsLinkDataExtended *) erts_link_to_data(lnk);
+
+    ERTS_ML_ASSERT(lnk->flags & ERTS_ML_FLG_EXTENDED);
+    ERTS_ML_ASSERT(lnk->type == ERTS_LNK_TYPE_DIST_PROC);
+    ERTS_ML_ASSERT(!ldep->dist);
+
+    ldep->dist = erts_mon_link_dist_create(nodename);
+    ldep->dist->alive = 0;
+}
+
+Uint
+erts_link_size(ErtsLink *lnk)
+{
+    Uint size, refc;
+    ErtsLinkData *ldp = erts_link_to_data(lnk);
+
+    if (!(lnk->flags & ERTS_ML_FLG_EXTENDED))
+        size = sizeof(ErtsLinkData);
+    else {
+        ErtsLinkDataExtended *ldep = (ErtsLinkDataExtended *) ldp;
+
+        ASSERT(lnk->type == ERTS_LNK_TYPE_DIST_PROC);
+        ASSERT(is_external_pid_header(ldep->heap[0]));
+
+        size = sizeof(ErtsLinkDataExtended);
+        size += thing_arityval(ldep->heap[0])*sizeof(Eterm);
+    }
+    
+    refc = (Uint) erts_atomic32_read_nob(&ldp->refc);
+    ASSERT(refc > 0);
+
+    return size / refc;
+}
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
+ * Misc                                                                      *
+\*                                                                           */
+
+void
+erts_monitor_link_init(void)
+{
+    monitor_init();
+    link_init();
+}
diff --git a/erts/emulator/beam/erl_monitor_link.h b/erts/emulator/beam/erl_monitor_link.h
new file mode 100644
index 0000000000..603aead8cc
--- /dev/null
+++ b/erts/emulator/beam/erl_monitor_link.h
@@ -0,0 +1,2326 @@
+/*
+ * %CopyrightBegin%
+ * 
+ * Copyright Ericsson AB 2018. All Rights Reserved.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * 
+ * %CopyrightEnd%
+ */
+
+/*
+ * Description:	Monitor and link implementation.
+ *
+ *              === Monitors ==================================================
+ *
+ *              The monitor data structure contains:
+ *              - an 'origin' part that should be inserted in a data structure
+ *                of the origin entity, i.e., the entity monitoring another
+ *                entity
+ *              - a 'target' part that should be inserted in a data structure
+ *                of the target entity, i.e., the entity being monitored by
+ *                another entity
+ *              - a shared part that contains information shared between both
+ *                origin and target entities
+ *
+ *              That is, the two halves of the monitor as well as shared data
+ *              are allocated in one single continuous memory block. The
+ *              origin and target parts can separately each be inserted in
+ *              either a (red-black) tree, a (circular double linked) list, or
+ *              in a process signal queue.
+ *
+ *              Each process and port contains:
+ *              - a monitor list for local target monitors that is accessed
+ *                via the ERTS_P_LT_MONITORS() macro, and
+ *              - a monitor tree for other monitors that is accessed via the
+ *                ERTS_P_MONITORS() macro
+ *
+ *              These fields of processes/ports are protected by the main lock
+ *              of the process/port. These are only intended to be accessed by
+ *              the process/port itself. When setting up or tearing down a
+ *              monitor one should *only* operate on the monitor tree/list of
+ *              the currently executing process/port and send signals to the
+ *              other involved process/port so it can modify its own monitor
+ *              tree/list by itself (see erl_proc_sig_queue.h). One should
+ *              absolutely *not* acquire the lock of the other involved
+ *              process/port and operate on its monitor tree/list directly.
+ *
+ *              Each dist entry contains a monitor/link dist structure that
+ *              contains:
+ *              - a monitor tree for origin named monitors that is accessed via
+ *                the field 'orig_name_monitors', and
+ *              - a monitor list for other monitors that is accessed via the
+ *                'monitors' field.
+ *              Monitors in these fields contain information about all monitors
+ *              over this specific connection.
+ *
+ *              The fields of the dist structure are protected by a mutex in
+ *              the same dist structure. Operations on these fields are
+ *              normally performed by the locally involved process only,
+ *              except when a connection is taken down. However in the case
+ *              of distributed named monitors that originates from another
+ *              node this is not possible. That is this operation is also
+ *              performed from another context that the locally involved
+ *              process.
+ *
+ *              Access to monitor trees are performed using the
+ *              erts_monitor_tree_* functions below. Access to monitor lists
+ *              are performed using the erts_monitor_list_* functions below.
+ *
+ *
+ *              The different monitor types:
+ *
+ *              --- ERTS_MON_TYPE_PROC ----------------------------------------
+ *
+ *              A local process (origin) monitors another local process
+ *              (target).
+ *
+ *              Origin:
+ *                      Other Item:     Target process identifier
+ *              Target:
+ *                      Other Item:     Origin process identifier
+ *              Shared:
+ *                      Key:            Reference
+ *                      Name:           Name (atom) if by name
+ *
+ *              Valid keys are only ordinary internal references.
+ *
+ *              Origin part of the monitor is stored in the monitor tree of
+ *              origin process and target part of the monitor is stored in
+ *              monitor list for local targets on the target process.
+ *
+ *              --- ERTS_MON_TYPE_PORT ----------------------------------------
+ *
+ *              A local process (origin) monitors a local port (target), or a
+ *              local port (origin) monitors a local process (target).
+ *
+ *              Origin:
+ *                      Other Item:     Target process/port identifier
+ *              Target:
+ *                      Other Item:     Origin process/port identifier
+ *              Shared:
+ *                      Key:            Reference
+ *                      Name:           Name (atom) if by name
+ *
+ *              Valid keys are only ordinary internal references.
+ *
+ *              Origin part of the monitor is stored in the monitor tree of
+ *              origin process/port and target part of the monitor is stored
+ *              in monitor list for local targets on the target process/port.
+ *
+ *
+ *              --- ERTS_MON_TYPE_TIME_OFFSET ---------------------------------
+ *
+ *              A local process (origin) monitors time offset (target)
+ *
+ *              Origin:
+ *                      Other Item:     clock_service
+ *              Target:
+ *                      Other Item:     Origin process identifier
+ *              Shared:
+ *                      Key:            Reference
+ *
+ *              Valid keys are only ordinary internal references.
+ *
+ *              Origin part of the monitor is stored in the monitor tree of
+ *              origin process and target part of the monitor is stored in
+ *              monitor list referred by the variable 'time_offset_monitors'
+ *              (see erl_time_sup.c).
+ *
+ *
+ *              --- ERTS_MON_TYPE_DIST_PROC -----------------------------------
+ *
+ *              A local process (origin) monitors a remote process (target).
+ *              Origin node on local process and target node on dist entry.
+ *
+ *              Origin:
+ *                      Other Item:     Remote process identifier/Node name
+ *                                      if by name
+ *              Target:
+ *                      Other Item:     Local process identifier
+ *              Shared:
+ *                      Key:            Reference
+ *                      Name:           Name (atom) if by name
+ *                      Dist:           Pointer to dist structure
+ *
+ *              Valid keys are only ordinary internal references.
+ *
+ *              Origin part of the monitor is stored in the monitor tree of
+ *              origin process and target part of the monitor is stored in
+ *              monitor list referred by 'monitors' field of the dist
+ *              structure.
+ *
+ *
+ *              A remote process (origin) monitors a local process (target).
+ *              Origin node on dist entry and target node on local process.
+ *
+ *              Origin:
+ *                      Other Item:     Local process identifier
+ *              Target:
+ *                      Other Item:     Remote process identifier
+ *              Shared:
+ *                      Key:            Reference
+ *                      Name:           Name (atom) if by name
+ *
+ *              Valid keys are only external references.
+ *
+ *              If monitor by name, the origin part of the monitor is stored
+ *              in the monitor tree referred by 'orig_name_monitors' field in
+ *              dist structure; otherwise in the monitor list referred by
+ *              'monitors' field in dist structure. The target part of the
+ *              monitor is stored in the monitor tree of the local target
+ *              process.
+ *
+ *
+ *              --- ERTS_MON_TYPE_RESOURCE ------------------------------------
+ *
+ *              A NIF resource (origin) monitors a process (target).
+ *
+ *              Origin:
+ *                      Other Item:     Target process identifier
+ *              Target:
+ *                      Other Ptr:      Pointer to resource
+ *              Shared:
+ *                      Key:            Reference
+ *
+ *              Valid keys are only ordinary internal references.
+ *
+ *              Origin part of the monitor is stored in the monitor tree of
+ *              origin resource (see erl_nif.c) and target part of the
+ *              monitor is stored in monitor list for local targets on the
+ *              target process.
+ *
+ *              --- ERTS_MON_TYPE_NODE ----------------------------------------
+ *
+ *              A local process (origin) monitors a distribution connection
+ *              (target) via erlang:monitor_node().
+ *
+ *              Origin:
+ *                      Other Item:     Node name (atom)
+ *                      Key:            Node name
+ *              Target:
+ *                      Other Item:     Origin process identifier
+ *                      Key:            Origin process identifier
+ *              Shared:
+ *                      Refc:           Number of invocations
+ *
+ *              Valid keys are only node-name atoms and internal process
+ *              identifiers.
+ *
+ *              Origin part of the monitor is stored in the monitor tree of
+ *              origin process and target part of the monitor is stored in
+ *              monitor list referred by 'monitors' field of the dist
+ *              structure.
+ *
+ *              --- ERTS_MON_TYPE_NODES ---------------------------------------
+ *
+ *              A local process (origin) monitors all connections (target),
+ *              via net_kernel:monitor_nodes().
+ *
+ *              Origin:
+ *                      Other Item:     Bit mask (small)
+ *                      Key:            Bit mask
+ *              Target:
+ *                      Other Item:     Origin process identifier
+ *                      Key:            Origin process identifier
+ *              Shared:
+ *                      Refc:           Number of invocations
+ *
+ *              Valid keys are only small integers and internal process
+ *              identifiers.
+ *
+ *              Origin part of the monitor is stored in the monitor tree of
+ *              origin process and target part of the monitor is stored in
+ *              monitor list referred by the variable 'nodes_monitors' (see
+ *              dist.c).
+ *
+ *              --- ERTS_MON_TYPE_SUSPEND -------------------------------------
+ *
+ *              Suspend monitor.
+ *
+ *              Other Item:         Suspendee process identifier
+ *              Key:                Suspendee process identifier
+ *
+ *              Valid keys are only ordinary internal references.
+ *
+ *              This type of monitor is a bit strange and the whole process
+ *              suspend functionality should be improved...
+ *
+ *
+ *
+ *              === Links =====================================================
+ *
+ *              The link data structure contains:
+ *              - an 'a' part that should be inserted in a data structure of
+ *                one entity and contains the identifier of the other involved
+ *                entity (b)
+ *              - a 'b' part that should be inserted in a data structure of
+ *                the other involved entity and contains the identifier of the
+ *                other involved entity (a)
+ *              - shared part that contains information shared between both
+ *                involved entities
+ *
+ *              That is, the two halves of the link as well as shared data
+ *              are allocated in one single continuous memory block. The 'a'
+ *              and the 'b' parts can separately each be inserted in either
+ *              a (red-black) tree, a (circular double linked) list, or in a
+ *              process signal queue.
+ *
+ *              Each process and port contains:
+ *              - a link tree for links that is accessed via the
+ *                ERTS_P_LINKS() macro
+ *
+ *              This field of processes/ports is protected by the main lock of
+ *              the process/port. It is only intended to be accessed by the
+ *              process/port itself. When setting up or tearing down a link
+ *              one should *only* operate on the link tree of the currently
+ *              executing process/port and send signals to the other involved
+ *              process/port so it can modify its own monitor tree by itself
+ *              (see erl_proc_sig_queue.h). One should absolutely *not*
+ *              acquire the lock of the other involved process/port and
+ *              operate on its link tree directly.
+ *
+ *              Each dist entry contains a monitor/link dist structure that
+ *              contains:
+ *              - a link list for links via the 'links' field.
+ *              Links in this field contain information about all links over
+ *              this specific connection.
+ *
+ *              The fields of the dist structure are protected by a mutex in
+ *              the same dist structure. Operation on the 'links' fields are
+ *              normally performed by the locally involved process only,
+ *              except when a connection is taken down.
+ *
+ *              Access to link trees are performed using the erts_link_tree_*
+ *              functions below. Access to link lists are performed using the
+ *              erts_link_list_* functions below.
+ *
+ *              There can only be one link between the same pair of
+ *              processes/ports. Since a link can be simultaneously initiated
+ *              from both ends we always save the link data structure with the
+ *              lowest address if multiple links should appear between the
+ *              same pair of processes/ports.
+ *
+ *
+ *              The different link types:
+ *
+ *              --- ERTS_LNK_TYPE_PROC -----------------------------------------
+ *
+ *              A link between a local process A and a local process B.
+ *
+ *              A:
+ *                      Other Item:     B process identifier
+ *                      Key:            B process identifier
+ *              B:
+ *                      Other Item:     A process identifier
+ *                      Key:            A process identifier
+ *
+ *              Valid keys are only internal process identifiers.
+ *
+ *              'A' part of the link stored in the link tree of process A and
+ *              'B' part of the link is stored in link tree of process B.
+ *
+ *              --- ERTS_LNK_TYPE_PORT -----------------------------------------
+ *
+ *              A link between a local process/port A and a local process/port
+ *              B.
+ *
+ *              A:
+ *                      Other Item:     B process/port identifier
+ *                      Key:            B process/port identifier
+ *              B:
+ *                      Other Item:     A process/port identifier
+ *                      Key:            A process/port identifier
+ *
+ *              Valid keys are internal process identifiers and internal port
+ *              identifiers.
+ *
+ *              'A' part of the link stored in the link tree of process/port
+ *              A and 'B' part of the link is stored in link tree of
+ *              process/port B.
+ *
+ *              --- ERTS_LNK_TYPE_DIST_PROC ------------------------------------
+ *
+ *              A link between a local process and a remote process. Either of
+ *              the processes can be used as A or B.
+ *
+ *              A:
+ *                      Other Item:     B process identifier
+ *                      Key:            B process identifier
+ *              B:
+ *                      Other Item:     A process identifier
+ *                      Key:            A process identifier
+ *              Shared:
+ *                      Dist:           Pointer to dist structure
+ *
+ *              Valid keys are internal and external process identifiers.
+ *
+ *              The part of the link with a remote pid as "other item" is
+ *              stored in the link tree of the local process. The part of
+ *              the link with a local pid as "other item" is stored in the
+ *              links list of the dist structure.
+ *
+ *              ===============================================================
+ *
+ * Author: 	Rickard Green
+ *
+ */
+
+#ifndef ERL_MONITOR_LINK_H__
+#define ERL_MONITOR_LINK_H__
+
+#define ERTS_PROC_SIG_QUEUE_TYPE_ONLY
+#include "erl_proc_sig_queue.h"
+#undef ERTS_PROC_SIG_QUEUE_TYPE_ONLY
+
+#if defined(DEBUG) || 0
+#  define ERTS_ML_DEBUG
+#else
+#  undef ERTS_ML_DEBUG
+#endif
+
+#ifdef ERTS_ML_DEBUG
+#  define ERTS_ML_ASSERT ERTS_ASSERT
+#else
+#  define ERTS_ML_ASSERT(E) ((void) 1)
+#endif
+
+#define ERTS_MON_TYPE_MAX               ((Uint16) 7)
+
+#define ERTS_MON_TYPE_PROC              ((Uint16) 0)
+#define ERTS_MON_TYPE_PORT              ((Uint16) 1)
+#define ERTS_MON_TYPE_TIME_OFFSET       ((Uint16) 2)
+#define ERTS_MON_TYPE_DIST_PROC         ((Uint16) 3)
+#define ERTS_MON_TYPE_RESOURCE          ((Uint16) 4)
+#define ERTS_MON_TYPE_NODE              ((Uint16) 5)
+#define ERTS_MON_TYPE_NODES             ((Uint16) 6)
+#define ERTS_MON_TYPE_SUSPEND           ERTS_MON_TYPE_MAX
+
+#define ERTS_MON_LNK_TYPE_MAX           (ERTS_MON_TYPE_MAX + ((Uint16) 3))
+#define ERTS_LNK_TYPE_MAX               ERTS_MON_LNK_TYPE_MAX
+
+#define ERTS_LNK_TYPE_PROC              (ERTS_MON_TYPE_MAX + ((Uint16) 1))
+#define ERTS_LNK_TYPE_PORT              (ERTS_MON_TYPE_MAX + ((Uint16) 2))
+#define ERTS_LNK_TYPE_DIST_PROC         ERTS_LNK_TYPE_MAX
+
+#define ERTS_ML_FLG_TARGET              (((Uint16) 1) << 0)
+#define ERTS_ML_FLG_IN_TABLE            (((Uint16) 1) << 1)
+#define ERTS_ML_FLG_IN_SUBTABLE         (((Uint16) 1) << 2)
+#define ERTS_ML_FLG_NAME                (((Uint16) 1) << 3)
+#define ERTS_ML_FLG_EXTENDED            (((Uint16) 1) << 4)
+
+#define ERTS_ML_FLG_DBG_VISITED         (((Uint16) 1) << 15)
+
+/* Flags that should be the same on both monitor/link halves */
+#define ERTS_ML_FLGS_SAME \
+    (ERTS_ML_FLG_EXTENDED|ERTS_ML_FLG_NAME)
+
+typedef struct ErtsMonLnkNode__ ErtsMonLnkNode;
+
+typedef struct {
+    UWord parent; /* Parent ptr and flags... */
+    ErtsMonLnkNode *right;
+    ErtsMonLnkNode *left;
+} ErtsMonLnkTreeNode;
+
+typedef struct {
+    ErtsMonLnkNode *next;
+    ErtsMonLnkNode *prev;
+} ErtsMonLnkListNode;
+
+struct ErtsMonLnkNode__ {
+    union {
+        ErtsSignalCommon signal;
+        ErtsMonLnkTreeNode tree;
+        ErtsMonLnkListNode list;
+    } node;
+    union {
+        Eterm item;
+        void *ptr;
+    } other;
+    Uint16 offset; /* offset from monitor/link data to this structure (node) */
+    Uint16 key_offset; /* offset from this structure (node) to key */
+    Uint16 flags;
+    Uint16 type;
+};
+
+typedef struct {
+    Eterm nodename;
+    Uint32 connection_id;
+    erts_atomic_t refc;
+    erts_mtx_t mtx;
+    int alive;
+    ErtsMonLnkNode *links; /* Link double linked circular list */
+    ErtsMonLnkNode *monitors; /* Monitor double linked circular list */
+    ErtsMonLnkNode *orig_name_monitors; /* Origin named monitors
+                                           read-black tree */
+} ErtsMonLnkDist;
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
+ * Misc                                                                      *
+\*                                                                           */
+
+/**
+ *
+ * @brief Initialize monitor/link implementation
+ *
+ */
+void erts_monitor_link_init(void);
+
+/**
+ *
+ * @brief Create monitor/link dist structure to attach to dist entry
+ *
+ * Create dist structure containing monitor and link containers. This
+ * structure is to be attached to a connected dist entry.
+ *
+ * @param[in]     nodename      Node name as an atom
+ *
+ * @returns                     Pointer to dist structure
+ *
+ */
+ErtsMonLnkDist *erts_mon_link_dist_create(Eterm nodename);
+
+/**
+ *
+ * @brief Increase reference count of monitor/link dist structure
+ *
+ * @param[in]     mld           Pointer to dist structure
+ *
+ */
+ERTS_GLB_INLINE void erts_mon_link_dist_inc_refc(ErtsMonLnkDist *mld);
+
+/**
+ *
+ * @brief Decrease reference count of monitor/link dist structure
+ *
+ * @param[in]     mld           Pointer to dist structure
+ *
+ */
+ERTS_GLB_INLINE void erts_mon_link_dist_dec_refc(ErtsMonLnkDist *mld);
+
+/* internal functions... */
+ERTS_GLB_INLINE void erts_ml_dl_list_insert__(ErtsMonLnkNode **list,
+                                              ErtsMonLnkNode *ml);
+ERTS_GLB_INLINE void erts_ml_dl_list_delete__(ErtsMonLnkNode **list,
+                                              ErtsMonLnkNode *ml);
+ERTS_GLB_INLINE ErtsMonLnkNode *erts_ml_dl_list_first__(ErtsMonLnkNode *list);
+ERTS_GLB_INLINE ErtsMonLnkNode *erts_ml_dl_list_last__(ErtsMonLnkNode *list);
+void erts_mon_link_dist_destroy__(ErtsMonLnkDist *mld);
+ERTS_GLB_INLINE void *erts_ml_node_to_main_struct__(ErtsMonLnkNode *mln);
+
+/* implementations for globally inlined misc functions... */
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+
+ERTS_GLB_INLINE void
+erts_mon_link_dist_inc_refc(ErtsMonLnkDist *mld)
+{
+    ERTS_ML_ASSERT(erts_atomic_read_nob(&mld->refc) > 0);
+    erts_atomic_inc_nob(&mld->refc);
+}
+
+ERTS_GLB_INLINE void
+erts_mon_link_dist_dec_refc(ErtsMonLnkDist *mld)
+{
+    ERTS_ML_ASSERT(erts_atomic_read_nob(&mld->refc) > 0);
+    if (erts_atomic_dec_read_nob(&mld->refc) == 0)
+        erts_mon_link_dist_destroy__(mld);
+}
+
+ERTS_GLB_INLINE void *
+erts_ml_node_to_main_struct__(ErtsMonLnkNode *mln)
+{
+    return (void *) (((char *) mln) - ((size_t) mln->offset));
+}
+
+ERTS_GLB_INLINE void
+erts_ml_dl_list_insert__(ErtsMonLnkNode **list, ErtsMonLnkNode *ml)
+{
+    ErtsMonLnkNode *first = *list;
+    ERTS_ML_ASSERT(!(ml->flags & ERTS_ML_FLG_IN_TABLE));
+    if (!first) {
+        ml->node.list.next = ml->node.list.prev = ml;
+        *list = ml;
+    }
+    else {
+        ERTS_ML_ASSERT(first->node.list.prev->node.list.next == first);
+        ERTS_ML_ASSERT(first->node.list.next->node.list.prev == first);
+        ml->node.list.next = first;
+        ml->node.list.prev = first->node.list.prev;
+        first->node.list.prev = ml;
+        ml->node.list.prev->node.list.next = ml;
+    }
+    ml->flags |= ERTS_ML_FLG_IN_TABLE;
+}
+
+ERTS_GLB_INLINE void
+erts_ml_dl_list_delete__(ErtsMonLnkNode **list, ErtsMonLnkNode *ml)
+{
+    ERTS_ML_ASSERT(ml->flags & ERTS_ML_FLG_IN_TABLE);
+    if (ml->node.list.next == ml) {
+        ERTS_ML_ASSERT(ml->node.list.prev == ml);
+        ERTS_ML_ASSERT(*list == ml);
+
+        *list = NULL;
+    }
+    else {
+        ERTS_ML_ASSERT(ml->node.list.prev->node.list.next == ml);
+        ERTS_ML_ASSERT(ml->node.list.prev != ml);
+        ERTS_ML_ASSERT(ml->node.list.next->node.list.prev == ml);
+        ERTS_ML_ASSERT(ml->node.list.next != ml);
+
+        if (*list == ml)
+            *list = ml->node.list.next;
+        ml->node.list.prev->node.list.next = ml->node.list.next;
+        ml->node.list.next->node.list.prev = ml->node.list.prev;
+    }
+    ml->flags &= ~ERTS_ML_FLG_IN_TABLE;
+}
+
+ERTS_GLB_INLINE ErtsMonLnkNode *
+erts_ml_dl_list_first__(ErtsMonLnkNode *list)
+{
+    return list;
+}
+
+ERTS_GLB_INLINE ErtsMonLnkNode *
+erts_ml_dl_list_last__(ErtsMonLnkNode *list)
+{
+    if (!list)
+        return NULL;
+    return list->node.list.prev;
+}
+
+#endif /* ERTS_GLB_INLINE_INCL_FUNC_DEF */
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
+ * Monitor Operations                                                        *
+\*                                                                           */
+
+
+typedef struct ErtsMonLnkNode__ ErtsMonitor;
+
+typedef struct {
+    ErtsMonitor origin;
+    ErtsMonitor target;
+    Eterm ref;
+    erts_atomic32_t refc;
+} ErtsMonitorData;
+
+typedef struct {
+    ErtsMonitorData md;
+    ErtsORefThing oref_thing;
+} ErtsMonitorDataHeap;
+
+typedef struct ErtsMonitorDataExtended__ ErtsMonitorDataExtended;
+
+struct ErtsMonitorDataExtended__ {
+    ErtsMonitorData md;
+    union {
+        Eterm name;
+        Uint refc;
+    } u;
+    union {
+        struct erl_off_heap_header *ohhp;
+        ErtsMonitor *node_monitors;
+    } uptr;
+    ErtsMonLnkDist *dist;
+    Eterm heap[1]; /* heap start... */
+};
+
+typedef struct {
+    ErtsMonitor mon;
+    int pending;
+    int active;
+} ErtsMonitorSuspend;
+
+/* 
+ * --- Monitor tree operations ---
+ */
+
+/**
+ *
+ * @brief Lookup a monitor in a monitor tree
+ *
+ *
+ * @param[in]     root          Pointer to root of monitor tree
+ *
+ * @param[in]     key           Key of monitor to lookup
+ *
+ * @returns                     Pointer to a monitor with the
+ *                              key 'key', or NULL if no such
+ *                              monitor was found
+ *
+ */
+ErtsMonitor *erts_monitor_tree_lookup(ErtsMonitor *root, Eterm key);
+
+/**
+ *
+ * @brief Lookup or insert a monitor in a monitor tree
+ *
+ * When the funcion is called it is assumed that:
+ * - 'mon' monitor is not part of any tree or list
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in,out] root          Pointer to pointer to root of monitor tree
+ *
+ * @param[in]     mon           Monitor to insert if no monitor
+ *                              with the same key already exists
+ *
+ * @returns                     Pointer to a monitor with the
+ *                              key 'key'. If no monitor with the key
+ *                              'key' was found and 'mon' was inserted
+ *                              'mon' is returned.
+ *
+ */
+ErtsMonitor *erts_monotor_tree_lookup_insert(ErtsMonitor **root,
+                                             ErtsMonitor *mon);
+
+/**
+ *
+ * @brief Lookup or create a node or a nodes monitor in a monitor tree.
+ *
+ * Looks up an origin monitor with the key 'target' in the monitor tree.
+ * If it is not found, creates a monitor and returns a pointer to the
+ * origin monitor.
+ *
+ * When the funcion is called it is assumed that:
+ * - no target monitors with the key 'target' exists in the tree.
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in,out] root          Pointer to pointer to root of monitor tree
+ *
+ * @param[out]    created       Pointer to integer. The integer is set to
+ *                              a non-zero value if no monitor with key
+ *                              'target' was found, and a new monitor
+ *                              was created. If a monitor was found, it
+ *                              is set to zero.
+ *
+ * @param[in]     type          ERTS_MON_TYPE_NODE | ERTS_MON_TYPE_NODES
+ *
+ * @param[in]     origin        The key of the origin
+ *
+ * @param[in]     target        The key of the target
+ *
+ */
+ErtsMonitor *erts_monitor_tree_lookup_create(ErtsMonitor **root, int *created,
+                                             Uint16 type, Eterm origin,
+                                             Eterm target);
+
+/**
+ *
+ * @brief Insert a monitor in a monitor tree
+ *
+ * When the funcion is called it is assumed that:
+ * - no monitors with the same key that 'mon' exist in the tree
+ * - 'mon' is not part of any list of tree
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in,out] root          Pointer to pointer to root of monitor tree
+ *
+ * @param[in]     mon           Monitor to insert.
+ *
+ */
+void erts_monitor_tree_insert(ErtsMonitor **root, ErtsMonitor *mon);
+
+/**
+ *
+ * @brief Replace a monitor in a monitor tree
+ *
+ * When the funcion is called it is assumed that:
+ * - 'old' monitor and 'new' monitor have exactly the same key
+ * - 'old' monitor is part of the tree
+ * - 'new' monitor is not part of any tree or list
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in,out] root          Pointer to pointer to root of monitor tree
+ *
+ * @param[in]     old           Monitor to remove from the tree
+ *
+ * @param[in]     new           Monitor to insert into the tree
+ *
+ */
+void erts_monitor_tree_replace(ErtsMonitor **root, ErtsMonitor *old,
+                               ErtsMonitor *new);
+
+/**
+ *
+ * @brief Delete a monitor from a monitor tree
+ *
+ * When the funcion is called it is assumed that:
+ * - 'mon' monitor is part of the tree
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in,out] root          Pointer to pointer to root of monitor tree
+ *
+ * @param[in]     mon           Monitor to remove from the tree
+ *
+ */
+void erts_monitor_tree_delete(ErtsMonitor **root, ErtsMonitor *mon);
+
+/**
+ *
+ * @brief Call a function for each monitor in a monitor tree
+ *
+ * The funcion 'func' will be called with a pointer to a monitor
+ * as first argument and 'arg' as second argument for each monitor
+ * in the tree referred to by 'root'.
+ *
+ * @param[in]     root          Pointer to root of monitor tree
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ */
+void erts_monitor_tree_foreach(ErtsMonitor *root,
+                               void (*func)(ErtsMonitor *, void *),
+                               void *arg);
+
+/**
+ *
+ * @brief Call a function for each monitor in a monitor tree. Yield
+ *        if lots of monitors exist.
+ *
+ * The funcion 'func' will be called with a pointer to a monitor
+ * as first argument and 'arg' as second argument for each monitor
+ * in the tree referred to by 'root'.
+ *
+ * It is assumed that:
+ * - *yspp equals NULL on first call
+ * - this function is repetedly called with *yspp set
+ *   as set when previous call returned until a non-zero
+ *   value is returned.
+ * - no modifications are made on the tree between first call
+ *   and the call that returns a non-zero value
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in]     root          Pointer to root of monitor tree
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ * @param[in,out] vyspp         Pointer to a pointer to an internal state
+ *                              used by this function. At initial call
+ *                              *yspp should be NULL. When done *yspp
+ *                              will be NULL.
+ *
+ * @param[in]     limit         Maximum amount of monitors to process
+ *                              before yielding.
+ *
+ * @returns                     A non-zero value when all monitors has been
+ *                              processed, and zero when more work is needed.
+ *
+ */
+int erts_monitor_tree_foreach_yielding(ErtsMonitor *root,
+                                       void (*func)(ErtsMonitor *, void *),
+                                       void *arg,
+                                       void **vyspp,
+                                       Sint limit);
+
+/**
+ *
+ * @brief Delete all monitors from a monitor tree and call a function for
+ *        each monitor
+ *
+ * The funcion 'func' will be called with a pointer to a monitor
+ * as first argument and 'arg' as second argument for each monitor
+ * in the tree referred to by 'root'.
+ *
+ * @param[in,out] root          Pointer to pointer to root of monitor tree
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ */
+void erts_monitor_tree_foreach_delete(ErtsMonitor **root,
+                                      void (*func)(ErtsMonitor *, void *),
+                                      void *arg);
+
+/**
+ *
+ * @brief Delete all monitors from a monitor tree and call a function for
+ *        each monitor
+ *
+ * The funcion 'func' will be called with a pointer to a monitor
+ * as first argument and 'arg' as second argument for each monitor
+ * in the tree referred to by 'root'.
+ *
+ * It is assumed that:
+ * - *yspp equals NULL on first call
+ * - this function is repetededly called with *yspp set
+ *   as set when previous call returned until a non-zero
+ *   value is returned.
+ * - no modifications are made on the tree between first call
+ *   and the call that returns a non-zero value
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in,out] root          Pointer to pointer to root of monitor tree
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ * @param[in,out] vyspp         Pointer to a pointer to an internal state
+ *                              used by this function. At initial call
+ *                              *yspp should be NULL. When done *yspp
+ *                              will be NULL.
+ *
+ * @param[in]     limit         Maximum amount of monitors to process
+ *                              before yielding.
+ *
+ * @returns                     A non-zero value when all monitors has been
+ *                              processed, and zero when more work is needed.
+ *
+ */
+int erts_monitor_tree_foreach_delete_yielding(ErtsMonitor **root,
+                                              void (*func)(ErtsMonitor *, void *),
+                                              void *arg,
+                                              void **vyspp,
+                                              Sint limit);
+
+/*
+ * --- Monitor list operations --
+ */
+
+/**
+ *
+ * @brief Insert a monitor in a monitor list
+ *
+ * When the funcion is called it is assumed that:
+ * - 'mon' monitor is not part of any list or tree
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in,out] list          Pointer to pointer to monitor list
+ *
+ * @param[in]     mon           Monitor to insert
+ *
+ */
+ERTS_GLB_INLINE void erts_monitor_list_insert(ErtsMonitor **list, ErtsMonitor *mon);
+
+/**
+ *
+ * @brief Delete a monitor from a monitor list
+ *
+ * When the funcion is called it is assumed that:
+ * - 'mon' monitor is part of the list
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in,out] list          Pointer to pointer to monitor list
+ *
+ * @param[in]     mon           Monitor to remove from the list
+ *
+ */
+ERTS_GLB_INLINE void erts_monitor_list_delete(ErtsMonitor **list, ErtsMonitor *mon);
+
+/**
+ *
+ * @brief Get a pointer to first monitor in a monitor list
+ *
+ * The monitor will still remain in the list after the return
+ *
+ * @param[in] list              Pointer to monitor list
+ *
+ * @returns                     Pointer to first monitor in list if
+ *                              list is not empty. If list is empty
+ *                              NULL is returned.
+ *
+ */
+ERTS_GLB_INLINE ErtsMonitor *erts_monitor_list_first(ErtsMonitor *list);
+
+/**
+ *
+ * @brief Get a pointer to last monitor in a monitor list
+ *
+ * The monitor will still remain in the list after the return
+ *
+ * @param[in] list              Pointer to monitor list
+ *
+ * @returns                     Pointer to last monitor in list if
+ *                              list is not empty. If list is empty
+ *                              NULL is returned.
+ *
+ */
+ERTS_GLB_INLINE ErtsMonitor *erts_monitor_list_last(ErtsMonitor *list);
+
+/**
+ *
+ * @brief Call a function for each monitor in a monitor list
+ *
+ * The funcion 'func' will be called with a pointer to a monitor
+ * as first argument and 'arg' as second argument for each monitor
+ * in the tree referred to by 'list'.
+ *
+ * @param[in]     list          Pointer to root of monitor list
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ */
+void erts_monitor_list_foreach(ErtsMonitor *list,
+                               void (*func)(ErtsMonitor *, void *),
+                               void *arg);
+
+/**
+ *
+ * @brief Call a function for each monitor in a monitor list. Yield
+ *        if lots of monitors exist.
+ *
+ * The funcion 'func' will be called with a pointer to a monitor
+ * as first argument and 'arg' as second argument for each monitor
+ * in the tree referred to by 'root'.
+ *
+ * It is assumed that:
+ * - *yspp equals NULL on first call
+ * - this function is repetedly called with *yspp set
+ *   as set when previous call returned until a non-zero
+ *   value is returned.
+ * - no modifications are made on the tree between first call
+ *   and the call that returns a non-zero value
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in]     list          Pointer to monitor list
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ * @param[in,out] vyspp         Pointer to a pointer to an internal state
+ *                              used by this function. At initial call
+ *                              *yspp should be NULL. When done *yspp
+ *                              will be NULL.
+ *
+ * @param[in]     limit         Maximum amount of monitors to process
+ *                              before yielding.
+ *
+ * @returns                     A non-zero value when all monitors has been
+ *                              processed, and zero when more work is needed.
+ *
+ */
+int erts_monitor_list_foreach_yielding(ErtsMonitor *list,
+                                       void (*func)(ErtsMonitor *, void *),
+                                       void *arg,
+                                       void **vyspp,
+                                       Sint limit);
+
+/**
+ *
+ * @brief Delete all monitors from a monitor list and call a function for
+ *        each monitor
+ *
+ * The funcion 'func' will be called with a pointer to a monitor
+ * as first argument and 'arg' as second argument for each monitor
+ * in the tree referred to by 'root'.
+ *
+ * @param[in,out] list          Pointer to pointer to monitor list
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ */
+void erts_monitor_list_foreach_delete(ErtsMonitor **list,
+                                      void (*func)(ErtsMonitor *, void *),
+                                      void *arg);
+
+/**
+ *
+ * @brief Delete all monitors from a monitor list and call a function for
+ *        each monitor
+ *
+ * The funcion 'func' will be called with a pointer to a monitor
+ * as first argument and 'arg' as second argument for each monitor
+ * in the tree referred to by 'root'.
+ *
+ * It is assumed that:
+ * - *yspp equals NULL on first call
+ * - this function is repetededly called with *yspp set
+ *   as set when previous call returned until a non-zero
+ *   value is returned.
+ * - no modifications are made on the tree between first
+ *   and the call that returns a non-zero value
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in,out] list          Pointer to pointer to monitor list
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ * @param[in,out] vyspp         Pointer to a pointer to an internal state
+ *                              used by this function. At initial call
+ *                              *yspp should be NULL. When done *yspp
+ *                              will be NULL.
+ *
+ * @param[in]     limit         Maximum amount of monitors to process
+ *                              before yielding.
+ *
+ * @returns                     A non-zero value when all monitors has been
+ *                              processed, and zero when more work is needed.
+ *
+ */
+int erts_monitor_list_foreach_delete_yielding(ErtsMonitor **list,
+                                              void (*func)(ErtsMonitor *, void *),
+                                              void *arg,
+                                              void **vyspp,
+                                              Sint limit);
+
+/*
+ * --- Misc monitor operations ---
+ */
+
+/**
+ *
+ * @brief Create a monitor
+ *
+ * Can create all types of monitors exept for suspend monitors
+ *
+ * When the funcion is called it is assumed that:
+ * - 'ref' is an internal ordinary reference if type is ERTS_MON_TYPE_PROC,
+ *   ERTS_MON_TYPE_PORT, ERTS_MON_TYPE_TIME_OFFSET, or ERTS_MON_TYPE_RESOURCE
+ * - 'ref' is NIL if type is ERTS_MON_TYPE_NODE or ERTS_MON_TYPE_NODES
+ * - 'ref' is and ordinary internal reference or an external reference if
+ *   type is ERTS_MON_TYPE_DIST_PROC
+ * - 'name' is an atom or NIL if type is ERTS_MON_TYPE_PROC,
+ *   ERTS_MON_TYPE_PORT, or ERTS_MON_TYPE_DIST_PROC
+ * - 'name is NIL if type is ERTS_MON_TYPE_TIME_OFFSET, ERTS_MON_TYPE_RESOURCE,
+ *   ERTS_MON_TYPE_NODE, or ERTS_MON_TYPE_NODES
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in]     type          ERTS_MON_TYPE_PROC, ERTS_MON_TYPE_PORT,
+ *                              ERTS_MON_TYPE_TIME_OFFSET, ERTS_MON_TYPE_DIST_PROC,
+ *                              ERTS_MON_TYPE_RESOURCE, ERTS_MON_TYPE_NODE,
+ *                              or ERTS_MON_TYPE_NODES
+ *
+ * @param[in]     ref           A reference or NIL depending on type
+ *
+ * @param[in]     origin        The key of the origin
+ *
+ * @param[in]     target        The key of the target
+ *
+ */
+ErtsMonitorData *erts_monitor_create(Uint16 type, Eterm ref, Eterm origin,
+                                     Eterm target, Eterm name);
+
+/**
+ *
+ * @brief Get pointer to monitor data structure
+ *
+ * @param[in]    mon            Pointer to monitor
+ *
+ * @returns                     Pointer to monitor data structure
+ *
+ */
+ERTS_GLB_INLINE ErtsMonitorData *erts_monitor_to_data(ErtsMonitor *mon);
+
+/**
+ *
+ * @brief Check if monitor is a target monitor
+ *
+ * @param[in]    mon            Pointer to monitor to check
+ *
+ * @returns                     A non-zero value if target monitor;
+ *                              otherwise zero
+ *
+ */
+ERTS_GLB_INLINE int erts_monitor_is_target(ErtsMonitor *mon);
+
+/**
+ *
+ * @brief Check if monitor is an origin monitor
+ *
+ * @param[in]    mon            Pointer to monitor to check
+ *
+ * @returns                     A non-zero value if origin monitor;
+ *                              otherwise zero
+ *
+ */
+ERTS_GLB_INLINE int erts_monitor_is_origin(ErtsMonitor *mon);
+
+/**
+ *
+ * @brief Check if monitor is in tree or list
+ *
+ * @param[in]    mon            Pointer to monitor to check
+ *
+ * @returns                     A non-zero value if in tree or list;
+ *                              otherwise zero
+ *
+ */
+ERTS_GLB_INLINE int erts_monitor_is_in_table(ErtsMonitor *mon);
+
+/**
+ *
+ * @brief Release monitor
+ *
+ * When both the origin and the target part of the monitor have
+ * been released the monitor structure will be deallocated.
+ *
+ * When the funcion is called it is assumed that:
+ * - 'mon' monitor is not part of any list or tree
+ * - 'mon' is not referred to by any other structures
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in]    mon            Pointer to monitor
+ *
+ */
+ERTS_GLB_INLINE void erts_monitor_release(ErtsMonitor *mon);
+
+/**
+ *
+ * @brief Release both target and origin monitor structures simultaneously
+ *
+ * Release both the origin and target parts of the monitor
+ * simultaneously and deallocate the structure.
+ *
+ * When the funcion is called it is assumed that:
+ * - Neither the origin part nor the target part of the monitor
+ *   are not part of any list or tree
+ * - Neither the origin part nor the target part of the monitor
+ *   are referred to by any other structures
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in]    mdp            Pointer to monitor data structure
+ *
+ */
+ERTS_GLB_INLINE void erts_monitor_release_both(ErtsMonitorData *mdp);
+
+/**
+ *
+ * @brief Insert monitor in dist monitor tree or list
+ *
+ * When the funcion is called it is assumed that:
+ * - 'mon' monitor is not part of any list or tree
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in]    mon            Pointer to monitor
+ *
+ * @param[in]    dist           Pointer to dist structure
+ *
+ * @returns                     A non-zero value if inserted;
+ *                              otherwise, zero. The monitor
+ *                              is not inserted if the dist
+ *                              structure has been set in a
+ *                              dead state.
+ *
+ */
+ERTS_GLB_INLINE int erts_monitor_dist_insert(ErtsMonitor *mon, ErtsMonLnkDist *dist);
+
+/**
+ *
+ * @brief Delete monitor from dist monitor tree or list
+ *
+ * When the funcion is called it is assumed that:
+ * - 'mon' monitor earler has been inserted into 'dist'
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in]    mon            Pointer to monitor
+ *
+ * @param[in]    dist           Pointer to dist structure
+ *
+ * @returns                     A non-zero value if deleted;
+ *                              otherwise, zero. The monitor
+ *                              is not deleted if the dist
+ *                              structure has been set in a
+ *                              dead state or if it has already
+ *                              been deleted.
+ *
+ */
+ERTS_GLB_INLINE int erts_monitor_dist_delete(ErtsMonitor *mon);
+
+/**
+ *
+ * @brief Set dead dist structure on monitor
+ *
+ * @param[in]    mon            Pointer to monitor
+ *
+ * @param[in]    nodename       Name of remote node
+ *
+ */
+void
+erts_monitor_set_dead_dist(ErtsMonitor *mon, Eterm nodename);
+
+/**
+ *
+ * @brief Get charged size of monitor
+ *
+ * If the other side of the monitor has been released, the
+ * whole size of the monitor data structure is returned; otherwise,
+ * half of the size is returned.
+ *
+ * When the funcion is called it is assumed that:
+ * - 'mon' has not been released
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in]    mon            Pointer to monitor
+ *
+ * @returns                     Charged size in bytes
+ *
+ */
+Uint erts_monitor_size(ErtsMonitor *mon);
+
+
+/* internal function... */
+void erts_monitor_destroy__(ErtsMonitorData *mdp);
+
+/* implementations for globally inlined monitor functions... */
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+
+ERTS_GLB_INLINE int
+erts_monitor_is_target(ErtsMonitor *mon)
+{
+    return !!(mon->flags & ERTS_ML_FLG_TARGET);
+}
+
+ERTS_GLB_INLINE int
+erts_monitor_is_origin(ErtsMonitor *mon)
+{
+    return !(mon->flags & ERTS_ML_FLG_TARGET);
+}
+
+ERTS_GLB_INLINE int
+erts_monitor_is_in_table(ErtsMonitor *mon)
+{
+    return !!(mon->flags & ERTS_ML_FLG_IN_TABLE);
+}
+
+ERTS_GLB_INLINE void
+erts_monitor_list_insert(ErtsMonitor **list, ErtsMonitor *mon)
+{
+    erts_ml_dl_list_insert__((ErtsMonLnkNode **) list, (ErtsMonLnkNode *) mon);
+}
+
+ERTS_GLB_INLINE void
+erts_monitor_list_delete(ErtsMonitor **list, ErtsMonitor *mon)
+{
+    erts_ml_dl_list_delete__((ErtsMonLnkNode **) list, (ErtsMonLnkNode *) mon);
+}
+
+ERTS_GLB_INLINE ErtsMonitor *
+erts_monitor_list_first(ErtsMonitor *list)
+{
+    return (ErtsMonitor *) erts_ml_dl_list_first__((ErtsMonLnkNode *) list);
+}
+
+ERTS_GLB_INLINE ErtsMonitor *
+erts_monitor_list_last(ErtsMonitor *list)
+{
+    return (ErtsMonitor *) erts_ml_dl_list_last__((ErtsMonLnkNode *) list);
+}
+
+#ifdef ERTS_ML_DEBUG
+extern size_t erts_monitor_origin_offset;
+extern size_t erts_monitor_origin_key_offset;
+extern size_t erts_monitor_target_offset;
+extern size_t erts_monitor_target_key_offset;
+extern size_t erts_monitor_node_key_offset;
+#endif
+
+ERTS_GLB_INLINE ErtsMonitorData *
+erts_monitor_to_data(ErtsMonitor *mon)
+{
+    ErtsMonitorData *mdp = erts_ml_node_to_main_struct__((ErtsMonLnkNode *) mon);
+
+#ifdef ERTS_ML_DEBUG
+    ERTS_ML_ASSERT(!(mdp->origin.flags & ERTS_ML_FLG_TARGET));
+    ERTS_ML_ASSERT(erts_monitor_origin_offset == (size_t) mdp->origin.offset);
+    ERTS_ML_ASSERT(!!(mdp->target.flags & ERTS_ML_FLG_TARGET));
+    ERTS_ML_ASSERT(erts_monitor_target_offset == (size_t) mdp->target.offset);
+    if (mon->type == ERTS_MON_TYPE_NODE || mon->type == ERTS_MON_TYPE_NODES) {
+        ERTS_ML_ASSERT(erts_monitor_node_key_offset == (size_t) mdp->origin.key_offset);
+        ERTS_ML_ASSERT(erts_monitor_node_key_offset == (size_t) mdp->target.key_offset);
+    }
+    else {
+        ERTS_ML_ASSERT(erts_monitor_origin_key_offset == (size_t) mdp->origin.key_offset);
+        ERTS_ML_ASSERT(erts_monitor_target_key_offset == (size_t) mdp->target.key_offset);
+    }
+#endif
+
+    return mdp;
+}
+
+ERTS_GLB_INLINE void
+erts_monitor_release(ErtsMonitor *mon)
+{
+    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
+    ERTS_ML_ASSERT(!(mon->flags & ERTS_ML_FLG_IN_TABLE));
+    ERTS_ML_ASSERT(erts_atomic32_read_nob(&mdp->refc) > 0);
+
+    if (erts_atomic32_dec_read_nob(&mdp->refc) == 0)
+        erts_monitor_destroy__(mdp);
+}
+
+ERTS_GLB_INLINE void
+erts_monitor_release_both(ErtsMonitorData *mdp)
+{
+    ERTS_ML_ASSERT((mdp->origin.flags & ERTS_ML_FLGS_SAME)
+                   == (mdp->target.flags & ERTS_ML_FLGS_SAME));
+    ERTS_ML_ASSERT(!(mdp->origin.flags & ERTS_ML_FLG_IN_TABLE));
+    ERTS_ML_ASSERT(!(mdp->target.flags & ERTS_ML_FLG_IN_TABLE));
+    ERTS_ML_ASSERT(erts_atomic32_read_nob(&mdp->refc) >= 2);
+
+    if (erts_atomic32_add_read_nob(&mdp->refc, (erts_aint32_t) -2) == 0)
+        erts_monitor_destroy__(mdp);
+}
+
+ERTS_GLB_INLINE int
+erts_monitor_dist_insert(ErtsMonitor *mon, ErtsMonLnkDist *dist)
+{
+    ErtsMonitorDataExtended *mdep;
+    int insert;
+
+    ERTS_ML_ASSERT(mon->flags & ERTS_ML_FLG_EXTENDED);
+    ERTS_ML_ASSERT(mon->type == ERTS_MON_TYPE_DIST_PROC
+                   || mon->type == ERTS_MON_TYPE_NODE);
+
+    mdep = (ErtsMonitorDataExtended *) erts_monitor_to_data(mon);
+
+    ERTS_ML_ASSERT(!mdep->dist);
+    ERTS_ML_ASSERT(dist);
+    mdep->dist = dist;
+
+    erts_mon_link_dist_inc_refc(dist);
+
+    erts_mtx_lock(&dist->mtx);
+
+    insert = dist->alive;
+    if (insert) {
+        if ((mon->flags & (ERTS_ML_FLG_NAME
+                           | ERTS_ML_FLG_TARGET)) == ERTS_ML_FLG_NAME)
+            erts_monitor_tree_insert(&dist->orig_name_monitors, mon);
+        else
+            erts_monitor_list_insert(&dist->monitors, mon);
+    }
+
+    erts_mtx_unlock(&dist->mtx);
+
+    return insert;
+}
+
+ERTS_GLB_INLINE int
+erts_monitor_dist_delete(ErtsMonitor *mon)
+{
+    ErtsMonitorDataExtended *mdep;
+    ErtsMonLnkDist *dist;
+    Uint16 flags;
+    int delete;
+
+    ERTS_ML_ASSERT(mon->flags & ERTS_ML_FLG_EXTENDED);
+    ERTS_ML_ASSERT(mon->type == ERTS_MON_TYPE_DIST_PROC
+                   || mon->type == ERTS_MON_TYPE_NODE);
+
+    mdep = (ErtsMonitorDataExtended *) erts_monitor_to_data(mon);
+    dist = mdep->dist;
+    ERTS_ML_ASSERT(dist);
+
+    erts_mtx_lock(&dist->mtx);
+
+    flags = mon->flags;
+    delete = !!dist->alive & !!(flags & ERTS_ML_FLG_IN_TABLE);
+    if (delete) {
+        if ((flags & (ERTS_ML_FLG_NAME
+                      | ERTS_ML_FLG_TARGET)) == ERTS_ML_FLG_NAME)
+            erts_monitor_tree_delete(&dist->orig_name_monitors, mon);
+        else
+            erts_monitor_list_delete(&dist->monitors, mon);
+    }
+
+    erts_mtx_unlock(&dist->mtx);
+
+    return delete;
+}
+
+
+#endif /* ERTS_GLB_INLINE_INCL_FUNC_DEF */
+
+/* suspend monitors... */
+ErtsMonitorSuspend *erts_monitor_suspend_create(Eterm pid);
+ErtsMonitorSuspend *erts_monitor_suspend_tree_lookup_create(ErtsMonitor **root,
+                                                            int *created,
+                                                            Eterm pid);
+void erts_monitor_suspend_destroy(ErtsMonitorSuspend *msp);
+
+ERTS_GLB_INLINE ErtsMonitorSuspend *erts_monitor_suspend(ErtsMonitor *mon);
+
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+
+ERTS_GLB_INLINE ErtsMonitorSuspend *erts_monitor_suspend(ErtsMonitor *mon)
+{
+    ERTS_ML_ASSERT(!mon || mon->type == ERTS_MON_TYPE_SUSPEND);
+    return (ErtsMonitorSuspend *) mon;
+}
+
+#endif
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
+ * Link Operations                                                           *
+\*                                                                           */
+
+typedef struct ErtsMonLnkNode__ ErtsLink;
+
+typedef struct {
+    ErtsLink a;
+    ErtsLink b;
+    erts_atomic32_t refc;
+} ErtsLinkData;
+
+typedef struct {
+    ErtsLinkData ld;
+    struct erl_off_heap_header *ohhp;
+    ErtsMonLnkDist *dist;
+    Eterm heap[1]; /* heap start... */
+} ErtsLinkDataExtended;
+
+/*
+ * --- Link tree operations ---
+ */
+
+/**
+ *
+ * @brief Lookup a link in a link tree
+ *
+ *
+ * @param[in]     root          Pointer to root of link tree
+ *
+ * @param[in]     key           Key of link to lookup
+ *
+ * @returns                     Pointer to a link with the
+ *                              key 'key', or NULL if no such
+ *                              link was found
+ *
+ */
+ErtsLink *erts_link_tree_lookup(ErtsLink *root, Eterm item);
+
+/**
+ *
+ * @brief Lookup or insert a link in a link tree
+ *
+ * When the funcion is called it is assumed that:
+ * - 'lnk' link is not part of any tree or list
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in,out] root          Pointer to pointer to root of link tree
+ *
+ * @param[in]     lnk           Link to insert if no link
+ *                              with the same key already exists
+ *
+ * @returns                     Pointer to a link with the
+ *                              key 'key'. If no link with the key
+ *                              'key' was found and 'lnk' was inserted
+ *                              'lnk' is returned.
+ *
+ */
+ErtsLink *erts_link_tree_lookup_insert(ErtsLink **root, ErtsLink *lnk);
+
+/**
+ *
+ * @brief Lookup or create a link in a link tree.
+ *
+ * Looks up a link with the key 'other' in the link tree. If it is not
+ * found, creates and insert a link with the key 'other'.
+ *
+ * @param[in,out] root          Pointer to pointer to root of link tree
+ *
+ * @param[out]    created       Pointer to integer. The integer is set to
+ *                              a non-zero value if no link with key
+ *                              'other' was found, and a new link
+ *                              was created. If a link was found, it
+ *                              is set to zero.
+ *
+ * @param[in]     type          Type of link
+ *
+ * @param[in]     this          Id of this entity
+ *
+ * @param[in]     other         Id of other entity
+ *
+ */
+ErtsLink *erts_link_tree_lookup_create(ErtsLink **root, int *created,
+                                       Uint16 type, Eterm this, Eterm other);
+
+/**
+ *
+ * @brief Insert a link in a link tree
+ *
+ * When the funcion is called it is assumed that:
+ * - no links with the same key that 'lnk' exist in the tree
+ * - 'lnk' is not part of any list of tree
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in,out] root          Pointer to pointer to root of link tree
+ *
+ * @param[in]     lnk           Link to insert.
+ *
+ */
+void erts_link_tree_insert(ErtsLink **root, ErtsLink *lnk);
+
+/**
+ *
+ * @brief Replace a link in a link tree
+ *
+ * When the funcion is called it is assumed that:
+ * - 'old' link and 'new' link have exactly the same key
+ * - 'old' link is part of the tree
+ * - 'new' link is not part of any tree or list
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in,out] root          Pointer to pointer to root of link tree
+ *
+ * @param[in]     old           Link to remove from the tree
+ *
+ * @param[in]     new           Link to insert into the tree
+ *
+ */
+void erts_link_tree_replace(ErtsLink **root, ErtsLink *old, ErtsLink *new);
+
+/**
+ *
+ * @brief Replace a link in a link tree if key already exist based on adress
+ *
+ * Inserts the link 'lnk' in the tree if no link with the same key
+ * already exists in tree. If a link with the same key exists in
+ * the tree and 'lnk' has a lower address than the link in the
+ * tree, the existing link in the tree is replaced by 'lnk'.
+ *
+ * When the funcion is called it is assumed that:
+ * - 'lnk' link is not part of any tree or list
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in,out] root          Pointer to pointer to root of link tree
+ *
+ * @param[in]     lnk           Link to insert into the tree
+ *
+ * @returns                     A pointer to the link that is not part
+ *                              of the tree after this operation.
+ *
+ */
+ERTS_GLB_INLINE ErtsLink *erts_link_tree_insert_addr_replace(ErtsLink **root,
+                                                             ErtsLink *lnk);
+
+/**
+ *
+ * @brief Delete a link from a link tree
+ *
+ * When the funcion is called it is assumed that:
+ * - 'lnk' link is part of the tree
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in,out] root          Pointer to pointer to root of link tree
+ *
+ * @param[in]     lnk           Link to remove from the tree
+ *
+ */
+void erts_link_tree_delete(ErtsLink **root, ErtsLink *lnk);
+
+/**
+ *
+ * @brief Delete a link from a link tree based on key
+ *
+ * If link 'lnk' is in the tree, 'lnk' is deleted from the tree.
+ * If link 'lnk' is not in the tree, another link with the same
+ * key as 'lnk' is deleted from the tree if such a link exist.
+ *
+ * When the funcion is called it is assumed that:
+ * - if 'lnk' link is part of a tree or list, it is part of this tree
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in,out] root          Pointer to pointer to root of link tree
+ *
+ * @param[in]     lnk           Link to remove from the tree
+ *
+ * @returns                     A pointer to the link that was deleted
+ *                              from the tree, or NULL in case no link
+ *                              was deleted from the tree
+ *
+ */
+ERTS_GLB_INLINE ErtsLink *erts_link_tree_key_delete(ErtsLink **root, ErtsLink *lnk);
+
+/**
+ *
+ * @brief Call a function for each link in a link tree
+ *
+ * The funcion 'func' will be called with a pointer to a link
+ * as first argument and 'arg' as second argument for each link
+ * in the tree referred to by 'root'.
+ *
+ * @param[in]     root          Pointer to root of link tree
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ */
+void erts_link_tree_foreach(ErtsLink *root,
+                            void (*func)(ErtsLink *, void *),
+                            void *arg);
+
+/**
+ *
+ * @brief Call a function for each link in a link tree. Yield if lots
+ *        of links exist.
+ *
+ * The funcion 'func' will be called with a pointer to a link
+ * as first argument and 'arg' as second argument for each link
+ * in the tree referred to by 'root'.
+ *
+ * It is assumed that:
+ * - *yspp equals NULL on first call
+ * - this function is repetedly called with *yspp set
+ *   as set when previous call returned until a non-zero
+ *   value is returned.
+ * - no modifications are made on the tree between first call
+ *   and the call that returns a non-zero value
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in]     root          Pointer to root of link tree
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ * @param[in,out] vyspp         Pointer to a pointer to an internal state
+ *                              used by this function. At initial call
+ *                              *yspp should be NULL. When done *yspp
+ *                              will be NULL.
+ *
+ * @param[in]     limit         Maximum amount of links to process
+ *                              before yielding.
+ *
+ * @returns                     A non-zero value when all links has been
+ *                              processed, and zero when more work is needed.
+ *
+ */
+int erts_link_tree_foreach_yielding(ErtsLink *root,
+                                    void (*func)(ErtsLink *, void *),
+                                    void *arg,
+                                    void **vyspp,
+                                    Sint limit);
+
+/**
+ *
+ * @brief Delete all links from a link tree and call a function for
+ *        each link
+ *
+ * The funcion 'func' will be called with a pointer to a link
+ * as first argument and 'arg' as second argument for each link
+ * in the tree referred to by 'root'.
+ *
+ * @param[in,out] root          Pointer to pointer to root of link tree
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ */
+void erts_link_tree_foreach_delete(ErtsLink **root,
+                                   void (*func)(ErtsLink *, void *),
+                                   void *arg);
+
+/**
+ *
+ * @brief Delete all links from a link tree and call a function for
+ *        each link
+ *
+ * The funcion 'func' will be called with a pointer to a link
+ * as first argument and 'arg' as second argument for each link
+ * in the tree referred to by 'root'.
+ *
+ * It is assumed that:
+ * - *yspp equals NULL on first call
+ * - this function is repetededly called with *yspp set
+ *   as set when previous call returned until a non-zero
+ *   value is returned.
+ * - no modifications are made on the tree between first call
+ *   and the call that returns a non-zero value
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in,out] root          Pointer to pointer to root of link tree
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ * @param[in,out] vyspp         Pointer to a pointer to an internal state
+ *                              used by this function. At initial call
+ *                              *yspp should be NULL. When done *yspp
+ *                              will be NULL.
+ *
+ * @param[in]     limit         Maximum amount of links to process
+ *                              before yielding.
+ *
+ * @returns                     A non-zero value when all links has been
+ *                              processed, and zero when more work is needed.
+ *
+ */
+int erts_link_tree_foreach_delete_yielding(ErtsLink **root,
+                                           void (*func)(ErtsLink *, void *),
+                                           void *arg,
+                                           void **vyspp,
+                                           Sint limit);
+
+/* 
+ * --- Link list operations ---
+ */
+
+/**
+ *
+ * @brief Insert a link in a link list
+ *
+ * When the funcion is called it is assumed that:
+ * - 'lnk' link is not part of any list or tree
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in,out] list          Pointer to pointer to link list
+ *
+ * @param[in]     lnk           Link to insert
+ *
+ */
+ERTS_GLB_INLINE void erts_link_list_insert(ErtsLink **list, ErtsLink *lnk);
+
+/**
+ *
+ * @brief Delete a link from a link list
+ *
+ * When the funcion is called it is assumed that:
+ * - 'lnk' link is part of the list
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in,out] list          Pointer to pointer to link list
+ *
+ * @param[in]     lnk           Link to remove from the list
+ *
+ */
+ERTS_GLB_INLINE void erts_link_list_delete(ErtsLink **list, ErtsLink *lnk);
+
+/**
+ *
+ * @brief Get a pointer to first link in a link list
+ *
+ * The link will still remain in the list after the return
+ *
+ * @param[in] list              Pointer to link list
+ *
+ * @returns                     Pointer to first link in list if
+ *                              list is not empty. If list is empty
+ *                              NULL is returned.
+ *
+ */
+ERTS_GLB_INLINE ErtsLink *erts_link_list_first(ErtsLink *list);
+
+/**
+ *
+ * @brief Get a pointer to last link in a link list
+ *
+ * The link will still remain in the list after the return
+ *
+ * @param[in] list              Pointer to link list
+ *
+ * @returns                     Pointer to last link in list if
+ *                              list is not empty. If list is empty
+ *                              NULL is returned.
+ *
+ */
+ERTS_GLB_INLINE ErtsLink *erts_link_list_last(ErtsLink *list);
+
+/**
+ *
+ * @brief Call a function for each link in a link list
+ *
+ * The funcion 'func' will be called with a pointer to a link
+ * as first argument and 'arg' as second argument for each link
+ * in the tree referred to by 'list'.
+ *
+ * @param[in]     list          Pointer to root of link list
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ */
+void erts_link_list_foreach(ErtsLink *list,
+                            void (*func)(ErtsLink *, void *),
+                            void *arg);
+
+/**
+ *
+ * @brief Call a function for each link in a link list. Yield
+ *        if lots of links exist.
+ *
+ * The funcion 'func' will be called with a pointer to a link
+ * as first argument and 'arg' as second argument for each link
+ * in the tree referred to by 'root'.
+ *
+ * It is assumed that:
+ * - *yspp equals NULL on first call
+ * - this function is repetedly called with *yspp set
+ *   as set when previous call returned until a non-zero
+ *   value is returned.
+ * - no modifications are made on the tree between first call
+ *   and the call that returns a non-zero value
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in]     list          Pointer to link list
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ * @param[in,out] vyspp         Pointer to a pointer to an internal state
+ *                              used by this function. At initial call
+ *                              *yspp should be NULL. When done *yspp
+ *                              will be NULL.
+ *
+ * @param[in]     limit         Maximum amount of links to process
+ *                              before yielding.
+ *
+ * @returns                     A non-zero value when all links has been
+ *                              processed, and zero when more work is needed.
+ *
+ */
+int erts_link_list_foreach_yielding(ErtsLink *list,
+                                    void (*func)(ErtsLink *, void *),
+                                    void *arg,
+                                    void **vyspp,
+                                    Sint limit);
+
+/**
+ *
+ * @brief Delete all links from a link list and call a function for
+ *        each link
+ *
+ * The funcion 'func' will be called with a pointer to a link
+ * as first argument and 'arg' as second argument for each link
+ * in the tree referred to by 'root'.
+ *
+ * @param[in,out] list          Pointer to pointer to link list
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ */
+void erts_link_list_foreach_delete(ErtsLink **list,
+                                   void (*func)(ErtsLink *, void *),
+                                   void *arg);
+
+/**
+ *
+ * @brief Delete all links from a link list and call a function for
+ *        each link
+ *
+ * The funcion 'func' will be called with a pointer to a link
+ * as first argument and 'arg' as second argument for each link
+ * in the tree referred to by 'root'.
+ *
+ * It is assumed that:
+ * - *yspp equals NULL on first call
+ * - this function is repetededly called with *yspp set
+ *   as set when previous call returned until a non-zero
+ *   value is returned.
+ * - no modifications are made on the tree between first
+ *   and the call that returns a non-zero value
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in,out] list          Pointer to pointer to link list
+ *
+ * @param[in]     func          Pointer to function to call
+ *
+ * @param[in]     arg           Argument to pass as second argument in
+ *                              calls to 'func'
+ *
+ * @param[in,out] vyspp         Pointer to a pointer to an internal state
+ *                              used by this function. At initial call
+ *                              *yspp should be NULL. When done *yspp
+ *                              will be NULL.
+ *
+ * @param[in]     limit         Maximum amount of links to process
+ *                              before yielding.
+ *
+ * @returns                     A non-zero value when all links has been
+ *                              processed, and zero when more work is needed.
+ *
+ */
+int erts_link_list_foreach_delete_yielding(ErtsLink **list,
+                                           void (*func)(ErtsLink *, void *),
+                                           void *arg,
+                                           void **vyspp,
+                                           Sint limit);
+
+/*
+ * --- Misc link operations ---
+ */
+
+/**
+ *
+ * @brief Create a link
+ *
+ * Can create all types of links
+ *
+ * When the funcion is called it is assumed that:
+ * - 'ref' is an internal ordinary reference if type is ERTS_MON_TYPE_PROC,
+ *   ERTS_MON_TYPE_PORT, ERTS_MON_TYPE_TIME_OFFSET, or ERTS_MON_TYPE_RESOURCE
+ * - 'ref' is NIL if type is ERTS_MON_TYPE_NODE or ERTS_MON_TYPE_NODES
+ * - 'ref' is and ordinary internal reference or an external reference if
+ *   type is ERTS_MON_TYPE_DIST_PROC
+ * - 'name' is an atom or NIL if type is ERTS_MON_TYPE_PROC,
+ *   ERTS_MON_TYPE_PORT, or ERTS_MON_TYPE_DIST_PROC
+ * - 'name is NIL if type is ERTS_MON_TYPE_TIME_OFFSET, ERTS_MON_TYPE_RESOURCE,
+ *   ERTS_MON_TYPE_NODE, or ERTS_MON_TYPE_NODES
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in]     type          ERTS_MON_TYPE_PROC, ERTS_MON_TYPE_PORT,
+ *                              ERTS_MON_TYPE_TIME_OFFSET, ERTS_MON_TYPE_DIST_PROC,
+ *                              ERTS_MON_TYPE_RESOURCE, ERTS_MON_TYPE_NODE,
+ *                              or ERTS_MON_TYPE_NODES
+ *
+ * @param[in]     a             The key of entity a. Link structure a will
+ *                              have field other.item set to 'b'.
+ *
+ * @param[in]     b             The key of entity b. Link structure b will
+ *                              have field other.item set to 'a'.
+ *
+ */
+ErtsLinkData *erts_link_create(Uint16 type, Eterm a, Eterm b);
+
+/**
+ *
+ * @brief Get pointer to link data structure
+ *
+ * @param[in]    lnk            Pointer to link
+ *
+ * @returns                     Pointer to link data structure
+ *
+ */
+ERTS_GLB_INLINE ErtsLinkData *erts_link_to_data(ErtsLink *lnk);
+
+/**
+ *
+ * @brief Get pointer to the other link structure part of the link
+ *
+ * @param[in]    lnk            Pointer to link
+ *
+ * @param[out]   ldpp           Pointer to pointer to link data structure,
+ *                              if a non-NULL value is passed in the call
+ *
+ * @returns                     Pointer to other link
+ *
+ */
+ERTS_GLB_INLINE ErtsLink *erts_link_to_other(ErtsLink *lnk, ErtsLinkData **ldpp);
+
+/**
+ *
+ * @brief Check if link is in tree or list
+ *
+ * @param[in]    lnk            Pointer to lnk to check
+ *
+ * @returns                     A non-zero value if in tree or list;
+ *                              otherwise zero
+ *
+ */
+ERTS_GLB_INLINE int erts_link_is_in_table(ErtsLink *lnk);
+
+/**
+ *
+ * @brief Release link
+ *
+ * When both link halves part of the link have been released the link
+ * structure will be deallocated.
+ *
+ * When the funcion is called it is assumed that:
+ * - 'lnk' link is not part of any list or tree
+ * - 'lnk' is not referred to by any other structures
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in]    lnk            Pointer to link
+ *
+ */
+ERTS_GLB_INLINE void erts_link_release(ErtsLink *lnk);
+
+/**
+ *
+ * @brief Release both link halves of a link simultaneously
+ *
+ * Release both halves of a link simultaneously and deallocate
+ * the structure.
+ *
+ * When the funcion is called it is assumed that:
+ * - Neither of the parts of the link are part of any list or tree
+ * - Neither of the parts of the link or the link data structure
+ *   are referred to by any other structures
+ * If the above are not true, bad things will happen.
+ *
+ * @param[in]    mdp            Pointer to link data structure
+ *
+ */
+ERTS_GLB_INLINE void erts_link_release_both(ErtsLinkData *ldp);
+
+/**
+ *
+ * @brief Insert link in dist link list
+ *
+ * When the funcion is called it is assumed that:
+ * - 'lnk' link is not part of any list or tree
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in]    lnk            Pointer to link
+ *
+ * @param[in]    dist           Pointer to dist structure
+ *
+ * @returns                     A non-zero value if inserted;
+ *                              otherwise, zero. The link
+ *                              is not inserted if the dist
+ *                              structure has been set in a
+ *                              dead state.
+ *
+ */
+ERTS_GLB_INLINE int erts_link_dist_insert(ErtsLink *lnk, ErtsMonLnkDist *dist);
+
+/**
+ *
+ * @brief Delete link from dist link list
+ *
+ * When the funcion is called it is assumed that:
+ * - 'lnk' link earler has been inserted into 'dist'
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in]    lnk            Pointer to link
+ *
+ * @param[in]    dist           Pointer to dist structure
+ *
+ * @returns                     A non-zero value if deleted;
+ *                              otherwise, zero. The link
+ *                              is not deleted if the dist
+ *                              structure has been set in a
+ *                              dead state or if it has already
+ *                              been deleted.
+ *
+ */
+ERTS_GLB_INLINE int erts_link_dist_delete(ErtsLink *lnk);
+
+/**
+ *
+ * @brief Set dead dist structure on link
+ *
+ * @param[in]    lnk            Pointer to link
+ *
+ * @param[in]    nodename       Name of remote node
+ *
+ */
+void
+erts_link_set_dead_dist(ErtsLink *lnk, Eterm nodename);
+
+/**
+ *
+ * @brief Get charged size of link
+ *
+ * If the other side of the link has been released, the
+ * whole size of the link data structure is returned; otherwise,
+ * half of the size is returned.
+ *
+ * When the funcion is called it is assumed that:
+ * - 'lnk' has not been released
+ * If the above is not true, bad things will happen.
+ *
+ * @param[in]    lnk            Pointer to link
+ *
+ * @returns                     Charged size in bytes
+ *
+ */
+Uint erts_link_size(ErtsLink *lnk);
+
+/* internal function... */
+void erts_link_destroy__(ErtsLinkData *ldp);
+
+/* implementations for globally inlined link functions... */
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+
+#ifdef ERTS_ML_DEBUG
+extern size_t erts_link_a_offset;
+extern size_t erts_link_b_offset;
+extern size_t erts_link_key_offset;
+#endif
+
+ERTS_GLB_INLINE ErtsLinkData *
+erts_link_to_data(ErtsLink *lnk)
+{
+    ErtsLinkData *ldp = erts_ml_node_to_main_struct__((ErtsMonLnkNode *) lnk);
+
+#ifdef ERTS_ML_DEBUG
+    ERTS_ML_ASSERT(erts_link_a_offset == (size_t) ldp->a.offset);
+    ERTS_ML_ASSERT(erts_link_key_offset == (size_t) ldp->a.key_offset);
+    ERTS_ML_ASSERT(erts_link_b_offset == (size_t) ldp->b.offset);
+    ERTS_ML_ASSERT(erts_link_key_offset == (size_t) ldp->b.key_offset);
+#endif
+
+    return ldp;
+}
+
+ERTS_GLB_INLINE ErtsLink *
+erts_link_to_other(ErtsLink *lnk, ErtsLinkData **ldpp)
+{
+    ErtsLinkData *ldp = erts_link_to_data(lnk);
+    if (ldpp)
+        *ldpp = ldp;
+    return lnk == &ldp->a ? &ldp->b : &ldp->a;
+}
+
+ERTS_GLB_INLINE int
+erts_link_is_in_table(ErtsLink *lnk)
+{
+    return !!(lnk->flags & ERTS_ML_FLG_IN_TABLE);
+}
+
+ERTS_GLB_INLINE void
+erts_link_list_insert(ErtsLink **list, ErtsLink *lnk)
+{
+    erts_ml_dl_list_insert__((ErtsMonLnkNode **) list, (ErtsMonLnkNode *) lnk);
+}
+
+ERTS_GLB_INLINE void
+erts_link_list_delete(ErtsLink **list, ErtsLink *lnk)
+{
+    erts_ml_dl_list_delete__((ErtsMonLnkNode **) list, (ErtsMonLnkNode *) lnk);
+}
+
+ERTS_GLB_INLINE ErtsLink *
+erts_link_list_first(ErtsLink *list)
+{
+    return (ErtsLink *) erts_ml_dl_list_first__((ErtsMonLnkNode *) list);
+}
+
+ERTS_GLB_INLINE ErtsLink *
+erts_link_list_last(ErtsLink *list)
+{
+    return (ErtsLink *) erts_ml_dl_list_last__((ErtsMonLnkNode *) list);
+}
+
+ERTS_GLB_INLINE void
+erts_link_release(ErtsLink *lnk)
+{
+    ErtsLinkData *ldp = erts_link_to_data(lnk);
+    ERTS_ML_ASSERT(!(lnk->flags & ERTS_ML_FLG_IN_TABLE));
+    ERTS_ML_ASSERT(erts_atomic32_read_nob(&ldp->refc) > 0);
+    if (erts_atomic32_dec_read_nob(&ldp->refc) == 0)
+        erts_link_destroy__(ldp);
+}
+
+ERTS_GLB_INLINE void
+erts_link_release_both(ErtsLinkData *ldp)
+{
+    ERTS_ML_ASSERT(!(ldp->a.flags & ERTS_ML_FLG_IN_TABLE));
+    ERTS_ML_ASSERT(!(ldp->b.flags & ERTS_ML_FLG_IN_TABLE));
+    ERTS_ML_ASSERT(erts_atomic32_read_nob(&ldp->refc) >= 2);
+    if (erts_atomic32_add_read_nob(&ldp->refc, (erts_aint32_t) -2) == 0)
+        erts_link_destroy__(ldp);
+}
+
+ERTS_GLB_INLINE ErtsLink *
+erts_link_tree_insert_addr_replace(ErtsLink **root, ErtsLink *lnk)
+{
+    ErtsLink *lnk2 = erts_link_tree_lookup_insert(root, lnk);
+    if (!lnk2)
+        return NULL;
+    if (lnk2 < lnk)
+        return lnk;
+    erts_link_tree_replace(root, lnk2, lnk);
+    return lnk2;
+}
+
+ERTS_GLB_INLINE ErtsLink *
+erts_link_tree_key_delete(ErtsLink **root, ErtsLink *lnk)
+{
+    ErtsLink *dlnk;
+    if (erts_link_is_in_table(lnk))
+        dlnk = lnk;
+    else
+        dlnk = erts_link_tree_lookup(*root, lnk->other.item);
+    if (dlnk)
+        erts_link_tree_delete(root, dlnk);
+    return dlnk;
+}
+
+ERTS_GLB_INLINE int
+erts_link_dist_insert(ErtsLink *lnk, ErtsMonLnkDist *dist)
+{
+    ErtsLinkDataExtended *ldep;
+    int insert;
+
+    ERTS_ML_ASSERT(lnk->flags & ERTS_ML_FLG_EXTENDED);
+    ERTS_ML_ASSERT(lnk->type == ERTS_LNK_TYPE_DIST_PROC);
+
+    ldep = (ErtsLinkDataExtended *) erts_link_to_data(lnk);
+
+    ERTS_ML_ASSERT(!ldep->dist);
+    ERTS_ML_ASSERT(dist);
+    ldep->dist = dist;
+
+    erts_mon_link_dist_inc_refc(dist);
+
+    erts_mtx_lock(&dist->mtx);
+
+    insert = dist->alive;
+    if (insert)
+        erts_link_list_insert(&dist->links, lnk);
+
+    erts_mtx_unlock(&dist->mtx);
+
+    return insert;
+}
+
+ERTS_GLB_INLINE int
+erts_link_dist_delete(ErtsLink *lnk)
+{
+    ErtsLinkDataExtended *ldep;
+    ErtsMonLnkDist *dist;
+    int delete;
+
+    ERTS_ML_ASSERT(lnk->flags & ERTS_ML_FLG_EXTENDED);
+    ERTS_ML_ASSERT(lnk->type == ERTS_LNK_TYPE_DIST_PROC);
+
+    ldep = (ErtsLinkDataExtended *) erts_link_to_data(lnk);
+    dist = ldep->dist;
+    if (!dist)
+        return -1;
+
+    erts_mtx_lock(&dist->mtx);
+
+    delete = !!dist->alive & !!(lnk->flags & ERTS_ML_FLG_IN_TABLE);
+    if (delete)
+        erts_link_list_delete(&dist->links, lnk);
+
+    erts_mtx_unlock(&dist->mtx);
+
+    return delete;
+}
+
+
+#endif /* ERTS_GLB_INLINE_INCL_FUNC_DEF */
+
+#endif /* ERL_MONITOR_LINK_H__ */
diff --git a/erts/emulator/beam/erl_monitors.c b/erts/emulator/beam/erl_monitors.c
deleted file mode 100644
index 1c840d89f6..0000000000
--- a/erts/emulator/beam/erl_monitors.c
+++ /dev/null
@@ -1,1073 +0,0 @@
-/*
- * %CopyrightBegin%
- * 
- * Copyright Ericsson AB 2004-2017. All Rights Reserved.
- * 
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * 
- * %CopyrightEnd%
- */
-
-/**************************************************************************
- * Monitors and links data structure manipulation.
- * Monitors and links are organized as AVL trees with the reference as 
- * key in the monitor case and the pid of the linked process as key in the 
- * link case. Lookups the order of the references is somewhat special. Local 
- * references are strictly smaller than remote references and are sorted 
- * by inlined comparison functionality. Remote references are handled by the
- * usual cmp function.
- * Each Monitor is tagged with different tags depending on which end of the 
- * monitor it is.
- * A monitor is removed either explicitly by reference or all monitors are 
- * removed when the process exits. No need to access the monitor by pid.
- **************************************************************************/ 
-
-#ifdef HAVE_CONFIG_H
-#  include "config.h"
-#endif
-
-#include "sys.h"
-#include "erl_vm.h"
-#include "global.h"
-#include "erl_process.h"
-#include "error.h"
-#include "erl_db.h"
-#include "bif.h"
-#include "big.h"
-#include "erl_monitors.h"
-#include "erl_bif_unique.h"
-
-#define STACK_NEED 50
-#define MAX_MONITORS 0xFFFFFFFFUL
-
-#define DIR_LEFT 0
-#define DIR_RIGHT 1
-#define DIR_END 2 
-
-static erts_atomic_t tot_link_lh_size;
-
-/* Implements the sort order in monitor trees, which is different from 
-   the ordinary term order.
-   No short local ref's should ever exist (the ref is created by the bif's 
-   in runtime), therefore:
-   All local ref's are less than external ref's
-   Local ref's are inline-compared,
-   External ref's are compared by cmp */
-
-#if 0   
-#define CMP_MON_REF(Ref1,Ref2) \
-cmp((Ref1),(Ref2)) /* XXX, the inline comparision yet to be done */
-#else
-#define CMP_MON_REF(Ref1,Ref2) cmp_mon_ref((Ref1),(Ref2))
-#endif
-
-static ERTS_INLINE int cmp_mon_ref(Eterm ref1, Eterm ref2) 
-{
-    Eterm *b1, *b2;
-
-
-    b1 = boxed_val(ref1);
-    b2 = boxed_val(ref2);
-    if (is_ref_thing_header(*b1)) {
-	if (is_ref_thing_header(*b2)) {
-	    Uint32 *num1, *num2;
-	    if (is_ordinary_ref_thing(b1)) {
-		ErtsORefThing *rtp = (ErtsORefThing *) b1;
-		num1 = rtp->num;
-	    }
-	    else {
-		ErtsMRefThing *mrtp = (ErtsMRefThing *) b1;
-		num1 = mrtp->mb->refn;
-	    }
-	    if (is_ordinary_ref_thing(b2)) {
-		ErtsORefThing *rtp = (ErtsORefThing *) b2;
-		num2 = rtp->num;
-	    }
-	    else {
-		ErtsMRefThing *mrtp = (ErtsMRefThing *) b2;
-		num2 = mrtp->mb->refn;
-	    }
-	    return erts_internal_ref_number_cmp(num1, num2);
-	}
-	return -1;
-    }
-    if (is_ref_thing_header(*b2)) {
-	return 1;
-    }
-    return CMP(ref1,ref2);
-}
-	    
-#define CP_LINK_VAL(To, Hp, From)				\
-do {								\
-    if (is_immed(From))						\
-	(To) = (From);						\
-    else {							\
-	Uint i__;						\
-	Uint len__;						\
-	ASSERT((Hp));						\
-	ASSERT(is_internal_ordinary_ref((From))                 \
-               || is_external((From)));                         \
-	(To) = make_boxed((Hp));				\
-	len__ = thing_arityval(*boxed_val((From))) + 1;		\
-	for(i__ = 0; i__ < len__; i__++)			\
-	    (*((Hp)++)) = boxed_val((From))[i__];		\
-	if (is_external((To))) {				\
-	    external_thing_ptr((To))->next = NULL;		\
-	    erts_refc_inc(&(external_thing_ptr((To))->node->refc), 2);\
-	}							\
-    }								\
-} while (0)
-
-static ErtsMonitor *create_monitor(Uint type, Eterm ref, UWord entity, Eterm name)
-{
-     Uint mon_size = ERTS_MONITOR_SIZE;
-     ErtsMonitor *n;
-     Eterm *hp;
-
-     mon_size += NC_HEAP_SIZE(ref);
-     if (type != MON_NIF_TARGET && is_not_immed(entity)) {
-	 mon_size += NC_HEAP_SIZE(entity);
-     }
-
-     if (mon_size <= ERTS_MONITOR_SH_SIZE) {
-	 n = (ErtsMonitor *) erts_alloc(ERTS_ALC_T_MONITOR_SH,
-					mon_size*sizeof(Uint));
-     } else {
-	 n = (ErtsMonitor *) erts_alloc(ERTS_ALC_T_MONITOR_LH,
-					mon_size*sizeof(Uint));
-	 erts_atomic_add_nob(&tot_link_lh_size, mon_size*sizeof(Uint));
-     } 
-     hp = n->heap;
-
-
-     n->left = n->right = NULL; /* Always the same initial value*/
-     n->type = (Uint16) type;
-     n->balance = 0;            /* Always the same initial value */
-     n->name = name; /* atom() or [] */
-     CP_LINK_VAL(n->ref, hp, ref); /*XXX Unnecessary check, never immediate*/
-     if (type == MON_NIF_TARGET)
-         n->u.resource = (ErtsResource*)entity;
-     else
-         CP_LINK_VAL(n->u.pid, hp, (Eterm)entity);
-
-     return n;
-}
-
-static ErtsLink *create_link(Uint type, Eterm pid)
-{
-     Uint lnk_size = ERTS_LINK_SIZE;
-     ErtsLink *n;
-     Eterm *hp;
-
-     if (is_not_immed(pid)) {
-	 lnk_size += NC_HEAP_SIZE(pid);
-     }
-
-     if (lnk_size <= ERTS_LINK_SH_SIZE) {
-	 n = (ErtsLink *) erts_alloc(ERTS_ALC_T_NLINK_SH,
-				     lnk_size*sizeof(Uint));
-     } else {
-	 n = (ErtsLink *) erts_alloc(ERTS_ALC_T_NLINK_LH,
-				     lnk_size*sizeof(Uint));
-	 erts_atomic_add_nob(&tot_link_lh_size, lnk_size*sizeof(Uint));
-     } 
-     hp = n->heap;
-
-
-     n->left = n->right = NULL; /* Always the same initial value*/
-     n->type = (Uint16) type;
-     n->balance = 0;            /* Always the same initial value */
-     if (n->type == LINK_NODE) {
-	 ERTS_LINK_REFC(n) = 0;
-     } else {
-	 ERTS_LINK_ROOT(n) = NULL; 
-     }
-     CP_LINK_VAL(n->pid, hp, pid);
-
-     return n;
-}
-
-#undef CP_LINK_VAL
-
-static ErtsSuspendMonitor *create_suspend_monitor(Eterm pid)
-{
-    ErtsSuspendMonitor *smon = erts_alloc(ERTS_ALC_T_SUSPEND_MON,
-					  sizeof(ErtsSuspendMonitor));
-    smon->left = smon->right = NULL; /* Always the same initial value */
-    smon->balance = 0;               /* Always the same initial value */
-    smon->pending = 0;
-    smon->active = 0;
-    smon->pid = pid;
-    return smon;
-}
-
-void
-erts_init_monitors(void)
-{
-    erts_atomic_init_nob(&tot_link_lh_size, 0);
-}
-
-Uint
-erts_tot_link_lh_size(void)
-{
-    return (Uint) erts_atomic_read_nob(&tot_link_lh_size);
-}
-
-void erts_destroy_monitor(ErtsMonitor *mon)
-{
-    Uint mon_size = ERTS_MONITOR_SIZE;
-    ErlNode *node;
-
-    ASSERT(is_not_immed(mon->ref));
-    mon_size +=  NC_HEAP_SIZE(mon->ref);
-    if (is_external(mon->ref)) {
-	node = external_thing_ptr(mon->ref)->node;
-	erts_deref_node_entry(node);
-    }
-    if (mon->type != MON_NIF_TARGET && is_not_immed(mon->u.pid)) {
-	mon_size += NC_HEAP_SIZE(mon->u.pid);
-	if (is_external(mon->u.pid)) {
-	    node = external_thing_ptr(mon->u.pid)->node;
-	    erts_deref_node_entry(node);
-	}
-    }
-    if (mon_size <= ERTS_MONITOR_SH_SIZE) {
-	erts_free(ERTS_ALC_T_MONITOR_SH, (void *) mon);
-    } else {
-	erts_free(ERTS_ALC_T_MONITOR_LH, (void *) mon);
-	erts_atomic_add_nob(&tot_link_lh_size, -1*mon_size*sizeof(Uint));
-    }
-}
-    
-void erts_destroy_link(ErtsLink *lnk)
-{
-    Uint lnk_size = ERTS_LINK_SIZE;
-    ErlNode *node;
-
-    ASSERT(lnk->type == LINK_NODE || ERTS_LINK_ROOT(lnk) == NULL);
-
-    if (is_not_immed(lnk->pid)) {
-	lnk_size += NC_HEAP_SIZE(lnk->pid);
-	if (is_external(lnk->pid)) {
-	    node = external_thing_ptr(lnk->pid)->node;
-	    erts_deref_node_entry(node);
-	}
-    }
-    if (lnk_size <= ERTS_LINK_SH_SIZE) {
-	erts_free(ERTS_ALC_T_NLINK_SH, (void *) lnk);
-    } else {
-	erts_free(ERTS_ALC_T_NLINK_LH, (void *) lnk);
-	erts_atomic_add_nob(&tot_link_lh_size, -1*lnk_size*sizeof(Uint));
-    }
-}
-
-void erts_destroy_suspend_monitor(ErtsSuspendMonitor *smon)
-{
-    erts_free(ERTS_ALC_T_SUSPEND_MON, smon);
-}
-     
-static void insertion_rotation(int dstack[], int dpos, 
-			       void *tstack[], int tpos, 
-			       int state) {
-    
-    ErtsMonitorOrLink **this;
-    ErtsMonitorOrLink *p1, *p2, *p;
-    int dir;
-
-    while (state && ( dir = dstack[--dpos] ) != DIR_END) {
-	this = tstack[--tpos];
-	p = *this;
-	if (dir == DIR_LEFT) {
-	    switch (p->balance) {
-	    case 1:
-		p->balance = 0;
-		state = 0;
-		break;
-	    case 0:
-		p->balance = -1;
-		break;
-	    case -1: /* The icky case */
-		p1 = p->left;
-		if (p1->balance == -1) { /* Single LL rotation */
-		    p->left = p1->right;
-		    p1->right = p;
-		    p->balance = 0;
-		    (*this) = p1;
-		} else { /* Double RR rotation */
-		    p2 = p1->right;
-		    p1->right = p2->left;
-		    p2->left = p1;
-		    p->left = p2->right;
-		    p2->right = p;
-		    p->balance = (p2->balance == -1) ? +1 : 0;
-		    p1->balance = (p2->balance == 1) ? -1 : 0;
-		    (*this) = p2;
-		}
-		(*this)->balance = 0;
-		state = 0;
-		break;
-	    }
-	} else { /* dir == DIR_RIGHT */
-	    switch (p->balance) {
-	    case -1:
-		p->balance = 0;
-		state = 0;
-		break;
-	    case 0:
-		p->balance = 1;
-		break;
-	    case 1:
-		p1 = p->right;
-		if (p1->balance == 1) { /* Single RR rotation */
-		    p->right = p1->left;
-		    p1->left = p;
-		    p->balance = 0;
-		    (*this) = p1;
-		} else { /* Double RL rotation */
-		    p2 = p1->left;
-		    p1->left = p2->right;
-		    p2->right = p1;
-		    p->right = p2->left;
-		    p2->left = p;
-		    p->balance = (p2->balance == 1) ? -1 : 0;
-		    p1->balance = (p2->balance == -1) ? 1 : 0;
-		    (*this) = p2;
-		}
-		(*this)->balance = 0; 
-		state = 0;
-		break;
-	    }
-	}
-    }
-}
-
-void erts_add_monitor(ErtsMonitor **root, Uint type, Eterm ref, UWord entity, 
-		      Eterm name)
-{
-    void *tstack[STACK_NEED];
-    int tpos = 0;
-    int dstack[STACK_NEED+1];
-    int dpos = 1;
-    int state = 0;
-    ErtsMonitor **this = root;
-    Sint c;
-
-    ASSERT(is_internal_ordinary_ref(ref) || is_external_ref(ref));
-  
-    dstack[0] = DIR_END;
-    for (;;) {
-	if (!*this) { /* Found our place */
-	    state = 1;
-	    *this = create_monitor(type,ref,entity,name);
-	    break;
-	} else if ((c = CMP_MON_REF(ref,(*this)->ref)) < 0) { 
-	    /* go left */
-	    dstack[dpos++] = DIR_LEFT;
-	    tstack[tpos++] = this;
-	    this = &((*this)->left);
-	} else if (c > 0) { /* go right */
-	    dstack[dpos++] = DIR_RIGHT;
-	    tstack[tpos++] = this;
-	    this = &((*this)->right);
-	} else { /* Equal key is an error for monitors */
-	    erts_exit(ERTS_ERROR_EXIT,"Insertion of already present monitor!");
-	    break;
-	}
-    }
-    insertion_rotation(dstack, dpos, tstack, tpos, state);
-}
-
-
-/* Returns 0 if OK, < 0 if already present */
-int erts_add_link(ErtsLink **root, Uint type, Eterm pid)
-{
-    void *tstack[STACK_NEED];
-    int tpos = 0;
-    int dstack[STACK_NEED+1];
-    int dpos = 1;
-    int state = 0;
-    ErtsLink **this = root;
-    Sint c;
-  
-    dstack[0] = DIR_END;
-    for (;;) {
-	if (!*this) { /* Found our place */
-	    state = 1;
-	    *this = create_link(type,pid);
-	    break;
-	} else if ((c = CMP(pid,(*this)->pid)) < 0) {
-	    /* go left */
-	    dstack[dpos++] = DIR_LEFT;
-	    tstack[tpos++] = this;
-	    this = &((*this)->left);
-	} else if (c > 0) { /* go right */
-	    dstack[dpos++] = DIR_RIGHT;
-	    tstack[tpos++] = this;
-	    this = &((*this)->right);
-	} else { /* Equal key is an error for monitors */
-	    return -1;
-	}
-    }
-    insertion_rotation(dstack, dpos, tstack, tpos, state);
-    return 0;
-}
-
-ErtsSuspendMonitor *
-erts_add_or_lookup_suspend_monitor(ErtsSuspendMonitor **root, Eterm pid)
-{
-    void *tstack[STACK_NEED];
-    int tpos = 0;
-    int dstack[STACK_NEED+1];
-    int dpos = 1;
-    int state = 0;
-    ErtsSuspendMonitor **this = root;
-    ErtsSuspendMonitor *res;
-    Sint c;
-  
-    dstack[0] = DIR_END;
-    for (;;) {
-	if (!*this) { /* Found our place */
-	    state = 1;
-	    res = *this = create_suspend_monitor(pid);
-	    break;
-	} else if ((c = CMP(pid,(*this)->pid)) < 0) {
-	    /* go left */
-	    dstack[dpos++] = DIR_LEFT;
-	    tstack[tpos++] = this;
-	    this = &((*this)->left);
-	} else if (c > 0) { /* go right */
-	    dstack[dpos++] = DIR_RIGHT;
-	    tstack[tpos++] = this;
-	    this = &((*this)->right);
-	} else { /* Already here... */
-	    ASSERT((*this)->pid == pid);
-	    return *this;
-	}
-    }
-    insertion_rotation(dstack, dpos, tstack, tpos, state);
-    return res;
-}
-
-
-/* Returns the new or old link structure */
-ErtsLink *erts_add_or_lookup_link(ErtsLink **root, Uint type, Eterm pid)
-{
-    void *tstack[STACK_NEED];
-    int tpos = 0;
-    int dstack[STACK_NEED+1];
-    int dpos = 1;
-    int state = 0;
-    ErtsLink **this = root;
-    Sint c;
-    ErtsLink *ret = NULL;
-
-    dstack[0] = DIR_END;
-    for (;;) {
-	if (!*this) { /* Found our place */
-	    state = 1;
-	    *this = create_link(type,pid);
-	    ret = *this;
-	    break;
-	} else if ((c = CMP(pid,(*this)->pid)) < 0) {
-	    /* go left */
-	    dstack[dpos++] = DIR_LEFT;
-	    tstack[tpos++] = this;
-	    this = &((*this)->left);
-	} else if (c > 0) { /* go right */
-	    dstack[dpos++] = DIR_RIGHT;
-	    tstack[tpos++] = this;
-	    this = &((*this)->right);
-	} else { /* Equal key is an error for monitors */
-	    return *this;
-	}
-    }
-    insertion_rotation(dstack, dpos, tstack, tpos, state);
-    return ret;
-}
-
-
-/*
- * Deletion helpers
- */
-static int balance_left(ErtsMonitorOrLink **this) 
-{
-    ErtsMonitorOrLink *p, *p1, *p2;
-    int b1, b2, h = 1;
-    
-    p = *this;
-    switch (p->balance) {
-    case -1:
-	p->balance = 0;
-	break;
-    case 0:
-	p->balance = 1;
-	h = 0;
-	break;
-    case 1:
-	p1 = p->right;
-	b1 = p1->balance;
-	if (b1 >= 0) { /* Single RR rotation */
-	    p->right = p1->left;
-	    p1->left = p;
-	    if (b1 == 0) {
-		p->balance = 1;
-		p1->balance = -1;
-		h = 0;
-	    } else {
-		p->balance = p1->balance = 0;
-	    }
-	    (*this) = p1;
-	} else { /* Double RL rotation */
-	    p2 = p1->left;
-	    b2 = p2->balance;
-	    p1->left = p2->right;
-	    p2->right = p1;
-	    p->right = p2->left;
-	    p2->left = p;
-	    p->balance = (b2 == 1) ? -1 : 0;
-	    p1->balance = (b2 == -1) ? 1 : 0;
-	    p2->balance = 0;
-	    (*this) = p2;
-	}
-	break;
-    }
-    return h;
-}
-
-static int balance_right(ErtsMonitorOrLink **this) 
-{
-    ErtsMonitorOrLink *p, *p1, *p2;
-    int b1, b2, h = 1;
-    
-    p = *this;
-    switch (p->balance) {
-    case 1:
-	p->balance = 0;
-	break;
-    case 0:
-	p->balance = -1;
-	h = 0;
-	break;
-    case -1:
-	p1 = p->left;
-	b1 = p1->balance;
-	if (b1 <= 0) { /* Single LL rotation */
-	    p->left = p1->right;
-	    p1->right = p;
-	    if (b1 == 0) {
-		p->balance = -1;
-		p1->balance = 1;
-		h = 0;
-	    } else {
-		p->balance = p1->balance = 0;
-	    }
-	    (*this) = p1;
-	} else { /* Double LR rotation */
-	    p2 = p1->right;
-	    b2 = p2->balance;
-	    p1->right = p2->left;
-	    p2->left = p1;
-	    p->left = p2->right;
-	    p2->right = p;
-	    p->balance = (b2 == -1) ? 1 : 0;
-	    p1->balance = (b2 == 1) ? -1 : 0;
-	    p2->balance = 0;
-	    (*this) = p2;
-	}
-    }
-    return h;
-}
-
-static int delsub(ErtsMonitorOrLink **this) 
-{
-    ErtsMonitorOrLink **tstack[STACK_NEED];
-    int tpos = 0;
-    ErtsMonitorOrLink *q = (*this);
-    ErtsMonitorOrLink **r = &(q->left);
-    int h;
-
-    /*
-     * Walk down the tree to the right and search 
-     * for a void right child, pick that child out
-     * and return it to be put in the deleted 
-     * object's place.
-     */
-    
-    while ((*r)->right != NULL) {
-	tstack[tpos++] = r;
-	r = &((*r)->right);
-    }
-    *this = *r;
-    *r = (*r)->left;
-    (*this)->left = q->left;
-    (*this)->right = q->right;
-    (*this)->balance = q->balance;
-    tstack[0] = &((*this)->left);
-    h = 1;
-    while (tpos && h) {
-	r = tstack[--tpos];
-	h = balance_right(r);
-    }
-    return h;
-}
-
-ErtsMonitor *erts_remove_monitor(ErtsMonitor **root, Eterm ref) 
-{
-    ErtsMonitor **tstack[STACK_NEED];
-    int tpos = 0;
-    int dstack[STACK_NEED+1];
-    int dpos = 1;
-    int state = 0;
-    ErtsMonitor **this = root;
-    Sint c;
-    int dir;
-    ErtsMonitor *q = NULL;
-
-    dstack[0] = DIR_END;
-    for (;;) {
-	if (!*this) { /* Failure */
-	    return NULL;
-	} else if ((c = CMP_MON_REF(ref,(*this)->ref)) < 0) { 
-	    dstack[dpos++] = DIR_LEFT;
-	    tstack[tpos++] = this;
-	    this = &((*this)->left);
-	} else if (c > 0) { /* go right */
-	    dstack[dpos++] = DIR_RIGHT;
-	    tstack[tpos++] = this;
-	    this = &((*this)->right);
-	} else { /* Equal key, found the one to delete */
-	    q = (*this);
-	    if (q->right == NULL) {
-		(*this) = q->left;
-		state = 1;
-	    } else if (q->left == NULL) {
-		(*this) = q->right;
-		state = 1;
-	    } else {
-		dstack[dpos++] = DIR_LEFT;
-		tstack[tpos++] = this;
-		state = delsub((ErtsMonitorOrLink **) this);
-	    }
-	    break;
-	}
-    }
-    while (state && ( dir = dstack[--dpos] ) != DIR_END) {
-	this = tstack[--tpos];
-	if (dir == DIR_LEFT) {
-	    state = balance_left((ErtsMonitorOrLink **) this);
-	} else {
-	    state = balance_right((ErtsMonitorOrLink **) this);
-	}
-    }
-    return q;
-}
-
-ErtsLink *erts_remove_link(ErtsLink **root, Eterm pid) 
-{
-    ErtsLink **tstack[STACK_NEED];
-    int tpos = 0;
-    int dstack[STACK_NEED+1];
-    int dpos = 1;
-    int state = 0;
-    ErtsLink **this = root;
-    Sint c;
-    int dir;
-    ErtsLink *q = NULL;
-
-    dstack[0] = DIR_END;
-    for (;;) {
-	if (!*this) { /* Failure */
-	    return NULL;
-	} else if ((c = CMP(pid,(*this)->pid)) < 0) {
-	    dstack[dpos++] = DIR_LEFT;
-	    tstack[tpos++] = this;
-	    this = &((*this)->left);
-	} else if (c > 0) { /* go right */
-	    dstack[dpos++] = DIR_RIGHT;
-	    tstack[tpos++] = this;
-	    this = &((*this)->right);
-	} else { /* Equal key, found the one to delete */
-	    q = (*this);
-	    if (q->right == NULL) {
-		(*this) = q->left;
-		state = 1;
-	    } else if (q->left == NULL) {
-		(*this) = q->right;
-		state = 1;
-	    } else {
-		dstack[dpos++] = DIR_LEFT;
-		tstack[tpos++] = this;
-		state = delsub((ErtsMonitorOrLink **) this);
-	    }
-	    break;
-	}
-    }
-    while (state && ( dir = dstack[--dpos] ) != DIR_END) {
-	this = tstack[--tpos];
-	if (dir == DIR_LEFT) {
-	    state = balance_left((ErtsMonitorOrLink **) this);
-	} else {
-	    state = balance_right((ErtsMonitorOrLink **) this);
-	}
-    }
-    return q;
-}
-
-void
-erts_delete_suspend_monitor(ErtsSuspendMonitor **root, Eterm pid)
-{
-    ErtsSuspendMonitor **tstack[STACK_NEED];
-    int tpos = 0;
-    int dstack[STACK_NEED+1];
-    int dpos = 1;
-    int state = 0;
-    ErtsSuspendMonitor **this = root;
-    Sint c;
-    int dir;
-    ErtsSuspendMonitor *q = NULL;
-
-    dstack[0] = DIR_END;
-    for (;;) {
-	if (!*this) { /* Nothing found */
-	    return;
-	} else if ((c = CMP(pid,(*this)->pid)) < 0) {
-	    dstack[dpos++] = DIR_LEFT;
-	    tstack[tpos++] = this;
-	    this = &((*this)->left);
-	} else if (c > 0) { /* go right */
-	    dstack[dpos++] = DIR_RIGHT;
-	    tstack[tpos++] = this;
-	    this = &((*this)->right);
-	} else { /* Equal key, found the one to delete */
-	    q = (*this);
-	    ASSERT(q->pid == pid);
-	    if (q->right == NULL) {
-		(*this) = q->left;
-		state = 1;
-	    } else if (q->left == NULL) {
-		(*this) = q->right;
-		state = 1;
-	    } else {
-		dstack[dpos++] = DIR_LEFT;
-		tstack[tpos++] = this;
-		state = delsub((ErtsMonitorOrLink **) this);
-	    }
-	    erts_destroy_suspend_monitor(q);
-	    break;
-	}
-    }
-    while (state && ( dir = dstack[--dpos] ) != DIR_END) {
-	this = tstack[--tpos];
-	if (dir == DIR_LEFT) {
-	    state = balance_left((ErtsMonitorOrLink **) this);
-	} else {
-	    state = balance_right((ErtsMonitorOrLink **) this);
-	}
-    }
-}
-
-ErtsMonitor *erts_lookup_monitor(ErtsMonitor *root, Eterm ref) 
-{
-    Sint c;
-
-    for (;;) {
-	if (root == NULL || (c = CMP_MON_REF(ref,root->ref)) == 0) {
-	    return root;
-	} else if (c < 0) { 
-	    root = root->left;
-	} else { /* c > 0 */ 
-	    root = root->right;
-	} 
-    }
-}
-
-ErtsLink *erts_lookup_link(ErtsLink *root, Eterm pid) 
-{
-    Sint c;
-
-    for (;;) {
-	if (root == NULL || (c = CMP(pid,root->pid)) == 0) {
-	    return root;
-	} else if (c < 0) { 
-	    root = root->left;
-	} else { /* c > 0 */ 
-	    root = root->right;
-	} 
-    }
-}
-
-ErtsSuspendMonitor *
-erts_lookup_suspend_monitor(ErtsSuspendMonitor *root, Eterm pid) 
-{
-    Sint c;
-
-    for (;;) {
-	if (root == NULL || (c = CMP(pid,root->pid)) == 0) {
-	    return root;
-	} else if (c < 0) { 
-	    root = root->left;
-	} else { /* c > 0 */ 
-	    root = root->right;
-	} 
-    }
-}
-
-void erts_sweep_monitors(ErtsMonitor *root, 
-			 void (*doit)(ErtsMonitor *, void *),
-			 void *context) 
-{
-    ErtsMonitor *tstack[STACK_NEED];
-    int tpos = 0;
-    int dstack[STACK_NEED+1];
-    int dpos = 1;
-    int dir;
-    
-    dstack[0] = DIR_END;
-
-    for (;;) {
-	if (root == NULL) {
-	    if ((dir = dstack[dpos-1]) == DIR_END) {
-		return;
-	    }
-	    if (dir == DIR_LEFT) {
-		/* Still has DIR_RIGHT to do */
-		dstack[dpos-1] = DIR_RIGHT;
-		root = (tstack[tpos-1])->right;
-	    } else {
-		/* stacktop is an object to be deleted */
-		(*doit)(tstack[--tpos],context); /* expeted to do the 
-						    deletion */
-		--dpos;
-		root = NULL;
-	    }
-	} else {
-	    dstack[dpos++] = DIR_LEFT;
-	    tstack[tpos++] = root;
-	    root = root->left;
-	}
-    }
-}
-
-void erts_sweep_links(ErtsLink *root, 
-		      void (*doit)(ErtsLink *, void *),
-		      void *context) 
-{
-    ErtsLink *tstack[STACK_NEED];
-    int tpos = 0;
-    int dstack[STACK_NEED+1];
-    int dpos = 1;
-    int dir;
-    
-    dstack[0] = DIR_END;
-
-    for (;;) {
-	if (root == NULL) {
-	    if ((dir = dstack[dpos-1]) == DIR_END) {
-		return;
-	    }
-	    if (dir == DIR_LEFT) {
-		/* Still has DIR_RIGHT to do */
-		dstack[dpos-1] = DIR_RIGHT;
-		root = (tstack[tpos-1])->right;
-	    } else {
-		/* stacktop is an object to be deleted */
-		(*doit)(tstack[--tpos],context); /* expeted to do the 
-						    deletion */
-		--dpos;
-		root = NULL;
-	    }
-	} else {
-	    dstack[dpos++] = DIR_LEFT;
-	    tstack[tpos++] = root;
-	    root = root->left;
-	}
-    }
-}
-
-void erts_sweep_suspend_monitors(ErtsSuspendMonitor *root,
-				 void (*doit)(ErtsSuspendMonitor *, void *),
-				 void *context)
-{
-    ErtsSuspendMonitor *tstack[STACK_NEED];
-    int tpos = 0;
-    int dstack[STACK_NEED+1];
-    int dpos = 1;
-    int dir;
-    
-    dstack[0] = DIR_END;
-
-    for (;;) {
-	if (root == NULL) {
-	    if ((dir = dstack[dpos-1]) == DIR_END) {
-		return;
-	    }
-	    if (dir == DIR_LEFT) {
-		/* Still has DIR_RIGHT to do */
-		dstack[dpos-1] = DIR_RIGHT;
-		root = (tstack[tpos-1])->right;
-	    } else {
-		/* stacktop is an object to be deleted */
-		(*doit)(tstack[--tpos],context); /* expeted to do the 
-						    deletion */
-		--dpos;
-		root = NULL;
-	    }
-	} else {
-	    dstack[dpos++] = DIR_LEFT;
-	    tstack[tpos++] = root;
-	    root = root->left;
-	}
-    }
-}
-				
-
-/* Debug BIF, always present, but undocumented... */
-	    
-static void erts_dump_monitors(ErtsMonitor *root, int indent)
-{
-    if (root == NULL)
-	return;
-    erts_dump_monitors(root->right,indent+2);
-    erts_printf("%*s[%b16d:%b16u:%T:%T", indent, "", root->balance,
-		root->type, root->ref, root->name);
-    if (root->type == MON_NIF_TARGET)
-	erts_printf(":%p]\n", root->u.resource);
-    else
-	erts_printf(":%T]\n", root->u.pid);
-    erts_dump_monitors(root->left,indent+2);
-}
-
-static void erts_dump_links_aux(ErtsLink *root, int indent,
-				erts_dsprintf_buf_t *dsbufp)
-{
-    if (root == NULL)
-	return;
-    erts_dump_links_aux(root->right, indent+2, dsbufp);
-    dsbufp->str_len = 0;
-    erts_dsprintf(dsbufp, "%*s[%b16d:%b16u:%T:%p]", indent, "",
-		  root->balance, root->type, root->pid, ERTS_LINK_ROOT(root));
-    if (ERTS_LINK_ROOT(root) != NULL) {
-	ErtsLink *sub = ERTS_LINK_ROOT(root);
-	int len = dsbufp->str_len;
-	erts_dump_links_aux(sub->right, indent+len+5, dsbufp);
-	erts_dsprintf(dsbufp, "-> %*s[%b16d:%b16u:%T:%p]", indent, "",
-		      sub->balance, sub->type, sub->pid, ERTS_LINK_ROOT(sub));
-	erts_printf("%s\n", dsbufp->str);
-	erts_dump_links_aux(sub->left, indent+len+5, dsbufp);
-    } else {
-	erts_printf("%s\n", dsbufp->str);
-    }
-    erts_dump_links_aux(root->left, indent+2, dsbufp);
-}
-
-static void erts_dump_links(ErtsLink *root, int indent)
-{
-    erts_dsprintf_buf_t *dsbufp = erts_create_tmp_dsbuf(0);
-    erts_dump_links_aux(root, indent, dsbufp);
-    erts_destroy_tmp_dsbuf(dsbufp);
-}
-
-Eterm erts_debug_dump_monitors_1(BIF_ALIST_1)
-{
-    Process *p = BIF_P;
-    Eterm pid = BIF_ARG_1;
-    Process *rp;
-    DistEntry *dep;
-    rp = erts_pid2proc(p, ERTS_PROC_LOCK_MAIN, pid, ERTS_PROC_LOCK_LINK);
-    if (!rp) {
-	ERTS_ASSERT_IS_NOT_EXITING(p);
-	if (is_atom(pid) && is_node_name_atom(pid) &&
-	    (dep = erts_find_dist_entry(pid)) != NULL) {
-	    erts_printf("Dumping dist monitors-------------------\n");
-	    erts_de_links_lock(dep);
-	    erts_dump_monitors(dep->monitors,0);
-	    erts_de_links_unlock(dep);
-	    erts_printf("Monitors dumped-------------------------\n");
-	    BIF_RET(am_true);
-	} else {
-	    BIF_ERROR(p,BADARG);
-	}
-    } else {
-	erts_printf("Dumping pid monitors--------------------\n");
-	erts_dump_monitors(ERTS_P_MONITORS(rp),0);
-	erts_printf("Monitors dumped-------------------------\n");
-	erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-	BIF_RET(am_true);
-    }
-}
-
-Eterm erts_debug_dump_links_1(BIF_ALIST_1)
-{
-    Process *p = BIF_P;
-    Eterm pid = BIF_ARG_1;
-    Process *rp;
-    DistEntry *dep;
-    if (is_internal_port(pid)) {
-	Port *rport = erts_id2port_sflgs(pid,
-					 p,
-					 ERTS_PROC_LOCK_MAIN,
-					 ERTS_PORT_SFLGS_INVALID_LOOKUP);
-	if (rport) {
-	    erts_printf("Dumping port links----------------------\n");
-	    erts_dump_links(ERTS_P_LINKS(rport), 0);
-	    erts_printf("Links dumped----------------------------\n");
-	    erts_port_release(rport);
-	    BIF_RET(am_true);
-	} else {
-	    BIF_ERROR(p,BADARG);
-	}
-    } else {
-	rp = erts_pid2proc(p, ERTS_PROC_LOCK_MAIN, pid, ERTS_PROC_LOCK_LINK);
-	if (!rp) {
-	    ERTS_ASSERT_IS_NOT_EXITING(p);
-	    if (is_atom(pid) && is_node_name_atom(pid) &&
-		(dep = erts_find_dist_entry(pid)) != NULL) {
-		erts_printf("Dumping dist links----------------------\n");
-		erts_de_links_lock(dep);
-		erts_dump_links(dep->nlinks,0);
-		erts_de_links_unlock(dep);
-		erts_printf("Links dumped----------------------------\n");
-		BIF_RET(am_true);
-	    } else {
-		BIF_ERROR(p,BADARG);
-	    }
-
-	} else {
-	    erts_printf("Dumping pid links-----------------------\n");
-	    erts_dump_links(ERTS_P_LINKS(rp), 0);
-	    erts_printf("Links dumped----------------------------\n");
-	    erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-	    BIF_RET(am_true);
-	}
-    }
-}
-
-void erts_one_link_size(ErtsLink *lnk, void *vpu)
-{
-    Uint *pu = vpu;
-    *pu += ERTS_LINK_SIZE*sizeof(Uint);
-    if(is_not_immed(lnk->pid))
-	*pu += NC_HEAP_SIZE(lnk->pid)*sizeof(Uint);
-    if (lnk->type != LINK_NODE && ERTS_LINK_ROOT(lnk) != NULL) {
-	erts_doforall_links(ERTS_LINK_ROOT(lnk),&erts_one_link_size,vpu);
-    }
-}
-void erts_one_mon_size(ErtsMonitor *mon, void *vpu)
-{
-    Uint *pu = vpu;
-    *pu += ERTS_MONITOR_SIZE*sizeof(Uint);
-    if(mon->type != MON_NIF_TARGET && is_not_immed(mon->u.pid))
-	*pu += NC_HEAP_SIZE(mon->u.pid)*sizeof(Uint);
-    if(is_not_immed(mon->ref))
-	*pu += NC_HEAP_SIZE(mon->ref)*sizeof(Uint);
-}
diff --git a/erts/emulator/beam/erl_monitors.h b/erts/emulator/beam/erl_monitors.h
deleted file mode 100644
index 1cacecd7e9..0000000000
--- a/erts/emulator/beam/erl_monitors.h
+++ /dev/null
@@ -1,187 +0,0 @@
-/*
- * %CopyrightBegin%
- * 
- * Copyright Ericsson AB 2004-2017. All Rights Reserved.
- * 
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * 
- * %CopyrightEnd%
- */
-
-/**********************************************************************
- * Header for monitors and links data structures.
- * Monitors are kept in an AVL tree and the data structures for
- * the four different types of monitors are like this:
- **********************************************************************
- * Local monitor by pid/port: 
- * (Ref is always same in all involved data structures)
- **********************************************************************
- *        Process/Port X     Process Y
- *       +-------------+    +-------------+
- * Type: | MON_ORIGIN  |    | MON_TARGET  |
- *       +-------------+    +-------------+
- * Pid:  | Pid(Y)      |    | Pid/Port(X) |
- *       +-------------+    +-------------+
- * Name: | []          |    | []          |
- *       +-------------+    +-------------+
- **********************************************************************
- * Local monitor by name: (Ref is always same in all involved data structures)
- **********************************************************************
- *        Process X          Process Y (name foo)
- *       +-------------+    +-------------+
- * Type: | MON_ORIGIN  |    | MON_TARGET  |
- *       +-------------+    +-------------+
- * Pid:  | Pid(Y)      |    | Pid(X)      |
- *       +-------------+    +-------------+
- * Name: | Atom(foo)   |    | Atom(foo)   |
- *       +-------------+    +-------------+
- **********************************************************************
- * Remote monitor by pid: (Ref is always same in all involved data structures)
- **********************************************************************
- *                    Node A              |           Node B
- *       ---------------------------------+----------------------------------
- *        Process X (@A)   Distentry @A       Distentry @B     Process Y (@B)
- *                         for node B         for node A 
- *       +-------------+  +-------------+    +-------------+  +-------------+
- * Type: | MON_ORIGIN  |  | MON_TARGET  |    | MON_ORIGIN  |  | MON_TARGET  |
- *       +-------------+  +-------------+    +-------------+  +-------------+
- * Pid:  | Pid(Y)      |  | Pid(X)      |    | Pid(Y)      |  | Pid(X)      |
- *       +-------------+  +-------------+    +-------------+  +-------------+
- * Name: | []          |  | []          |    | []          |  | []          |
- *       +-------------+  +-------------+    +-------------+  +-------------+
- **********************************************************************
- * Remote monitor by name: (Ref is always same in all involved data structures)
- **********************************************************************
- *                    Node A              |           Node B
- *       ---------------------------------+----------------------------------
- *        Process X (@A)   Distentry @A       Distentry @B     Process Y (@B)
- *                         for node B         for node A       (name foo)
- *       +-------------+  +-------------+    +-------------+  +-------------+
- * Type: | MON_ORIGIN  |  | MON_TARGET  |    | MON_ORIGIN  |  | MON_TARGET  |
- *       +-------------+  +-------------+    +-------------+  +-------------+
- * Pid:  | Atom(node B)|  | Pid(X)      |    | Pid(Y)      |  | Pid(X)      |
- *       +-------------+  +-------------+    +-------------+  +-------------+
- * Name: | Atom(foo)   |  | Atom(foo)   |    | Atom(foo)   |  | Atom(foo)   |
- *       +-------------+  +-------------+    +-------------+  +-------------+
- * The reason for the node atom in X->pid is that we don't know the actual
- * pid of the monitored process on the other node when setting the monitor
- * (which is done asyncronously).
- **********************************************************************/
-#ifndef _ERL_MONITORS_H
-#define _ERL_MONITORS_H
-
-/* Type tags for monitors */
-#define MON_ORIGIN 1
-#define MON_TARGET 2
-#define MON_NIF_TARGET 3
-#define MON_TIME_OFFSET 4
-
-/* Type tags for links */
-#define LINK_PID 1   /* ...Or port */
-#define LINK_NODE 3  /* "Node monitor" */  
-
-/* Size of a monitor without heap, in words (fixalloc) */
-#define ERTS_MONITOR_SIZE ((sizeof(ErtsMonitor) - sizeof(Uint))/sizeof(Uint))
-#define ERTS_MONITOR_SH_SIZE (ERTS_MONITOR_SIZE + ERTS_REF_THING_SIZE)
-#define ERTS_LINK_SIZE ((sizeof(ErtsLink) - sizeof(Uint))/sizeof(Uint))
-#define ERTS_LINK_SH_SIZE ERTS_LINK_SIZE /* Size of fix-alloced links */
-
-/* ErtsMonitor and ErtsLink *need* to begin in a similar way as 
-   ErtsMonitorOrLink */
-typedef struct erts_monitor_or_link {
-    struct erts_monitor_or_link *left, *right;
-    Sint16 balance;    
-} ErtsMonitorOrLink;
-
-typedef struct erts_monitor {
-    struct erts_monitor *left, *right; 
-    Sint16 balance;
-    Uint16 type;  /* MON_ORIGIN | MON_TARGET | MON_NIF_TARGET | MON_TIME_OFFSET */
-    Eterm ref;
-    union {
-        Eterm pid;  /* In case of distributed named monitor, this is the
-		     * nodename atom in MON_ORIGIN process, otherwise a pid or,
-		     * in case of a MON_TARGET, a port
-                     */
-        struct ErtsResource_* resource; /* MON_NIF_TARGET */
-    }u;
-    Eterm name;   /* When monitoring a named process: atom() else [] */
-    Uint heap[1]; /* Larger in reality */
-} ErtsMonitor;
-
-typedef struct erts_link {
-    struct erts_link *left, *right;
-    Sint16 balance;
-    Uint16 type;             /* LINK_PID | LINK_NODE */
-    Eterm pid;               /* When node monitor, 
-				the node atom is here instead */
-    union {
-	struct erts_link *root;  /* Used only in dist entries */
-	Uint refc;
-    } shared;
-    Uint heap[1];            /* Larger in reality */
-} ErtsLink;   
-
-typedef struct erts_suspend_monitor {
-    struct erts_suspend_monitor *left, *right;
-    Sint16 balance;
-
-    int pending;
-    int active;
-    Eterm pid;
-} ErtsSuspendMonitor;
-
-#define ERTS_LINK_ROOT(Linkp) ((Linkp)->shared.root)
-#define ERTS_LINK_REFC(Linkp) ((Linkp)->shared.refc) 
-
-Uint erts_tot_link_lh_size(void);
-
-
-/* Prototypes */
-void erts_destroy_monitor(ErtsMonitor *mon);
-void erts_add_monitor(ErtsMonitor **root, Uint type, Eterm ref, UWord entity,
-		      Eterm name);
-ErtsMonitor *erts_remove_monitor(ErtsMonitor **root, Eterm ref);
-ErtsMonitor *erts_lookup_monitor(ErtsMonitor *root, Eterm ref);
-void erts_sweep_monitors(ErtsMonitor *root, 
-			 void (*doit)(ErtsMonitor *, void *),
-			 void *context);
-
-void erts_destroy_link(ErtsLink *lnk);
-/* Returns 0 if OK, < 0 if already present */
-int erts_add_link(ErtsLink **root, Uint type, Eterm pid);
-ErtsLink *erts_add_or_lookup_link(ErtsLink **root, Uint type, Eterm pid);
-ErtsLink *erts_remove_link(ErtsLink **root, Eterm pid);
-ErtsLink *erts_lookup_link(ErtsLink *root, Eterm pid);
-void erts_sweep_links(ErtsLink *root, 
-		      void (*doit)(ErtsLink *, void *),
-		      void *context);
-
-void erts_destroy_suspend_monitor(ErtsSuspendMonitor *sproc);
-void erts_sweep_suspend_monitors(ErtsSuspendMonitor *root,
-				 void (*doit)(ErtsSuspendMonitor *, void *),
-				 void *context);
-ErtsSuspendMonitor *erts_add_or_lookup_suspend_monitor(ErtsSuspendMonitor **root,
-						       Eterm pid);
-ErtsSuspendMonitor *erts_lookup_suspend_monitor(ErtsSuspendMonitor *root,
-						Eterm pid);
-void erts_delete_suspend_monitor(ErtsSuspendMonitor **root, Eterm pid);
-void erts_init_monitors(void);
-void erts_one_link_size(ErtsLink *lnk, void *vpu);
-void erts_one_mon_size(ErtsMonitor *mon, void *vpu);
-
-#define erts_doforall_monitors erts_sweep_monitors
-#define erts_doforall_links erts_sweep_links
-#define erts_doforall_suspend_monitors erts_sweep_suspend_monitors
-
-#endif /* _ERL_MONITORS_H */
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index c60cc7fecf..cd4fd7b635 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2009-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2009-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -57,6 +57,7 @@
 #include "erl_bif_unique.h"
 #include "erl_utils.h"
 #include "erl_io_queue.h"
+#include "erl_proc_sig_queue.h"
 #undef ERTS_WANT_NFUNC_SCHED_INTERNALS__
 #define ERTS_WANT_NFUNC_SCHED_INTERNALS__
 #include "erl_nfunc_sched.h"
@@ -658,7 +659,7 @@ int erts_flush_trace_messages(Process *c_p, ErtsProcLocks c_p_locks)
             rp_locks = 0;
             if (rp->common.id == c_p->common.id)
                 rp_locks = c_p_locks;
-            erts_queue_messages(rp, rp_locks, first, last, len, c_p->common.id);
+            erts_queue_messages(rp, rp_locks, first, last, len);
             if (rp->common.id == c_p->common.id)
                 rp_locks &= ~c_p_locks;
             if (rp_locks)
@@ -700,6 +701,7 @@ int enif_send(ErlNifEnv* env, const ErlNifPid* to_pid,
     Process* rp;
     Process* c_p;
     ErtsMessage *mp;
+    Eterm from;
     Eterm receiver = to_pid->pid;
     int scheduler;
 
@@ -778,7 +780,7 @@ int enif_send(ErlNifEnv* env, const ErlNifPid* to_pid,
         msg = copy_struct_litopt(msg, sz, &hp, ohp, &litarea);
     }
 
-    ERL_MESSAGE_TERM(mp) = msg;
+    from = c_p ? c_p->common.id : am_undefined;
 
     if (!env || !env->tracee) {
 
@@ -797,7 +799,6 @@ int enif_send(ErlNifEnv* env, const ErlNifPid* to_pid,
         ErlTraceMessageQueue *msgq;
         Process *t_p = env->tracee;
 
-
         erts_proc_lock(t_p, ERTS_PROC_LOCK_TRACE);
 
         msgq = t_p->trace_msg_q;
@@ -817,6 +818,9 @@ int enif_send(ErlNifEnv* env, const ErlNifPid* to_pid,
             rp_locks & ERTS_PROC_LOCK_MSGQ ||
             erts_proc_trylock(rp, ERTS_PROC_LOCK_MSGQ) == EBUSY) {
 
+            ERL_MESSAGE_TERM(mp) = msg;
+            ERL_MESSAGE_FROM(mp) = from;
+
             if (!msgq) {
                 msgq = erts_alloc(ERTS_ALC_T_TRACE_MSG_QUEUE,
                                   sizeof(ErlTraceMessageQueue));
@@ -846,8 +850,7 @@ int enif_send(ErlNifEnv* env, const ErlNifPid* to_pid,
         }
     }
 
-    erts_queue_message(rp, rp_locks, mp, msg,
-                       c_p ? c_p->common.id : am_undefined);
+    erts_queue_message(rp, rp_locks, mp, msg, from);
 
 done:
     if (c_p == rp)
@@ -2206,71 +2209,61 @@ static void rollback_opened_resource_types(void)
     }
 }
 
-struct destroy_monitor_ctx
-{
-    ErtsResource* resource;
-    int exiting_procs;
-    int scheduler;
-};
+#ifdef ARCH_64
+#  define ERTS_RESOURCE_DYING_FLAG (((Uint) 1) << 63)
+#else
+#  define ERTS_RESOURCE_DYING_FLAG (((Uint) 1) << 31)
+#endif
+#define ERTS_RESOURCE_REFC_MASK (~ERTS_RESOURCE_DYING_FLAG)
 
-static void destroy_one_monitor(ErtsMonitor* mon, void* context)
+static ERTS_INLINE void
+rmon_set_dying(ErtsResourceMonitors *rms)
 {
-    struct destroy_monitor_ctx* ctx = (struct destroy_monitor_ctx*) context;
-    Process* rp;
-    ErtsMonitor *rmon = NULL;
-    int is_exiting;
+    rms->refc |= ERTS_RESOURCE_DYING_FLAG;
+}
 
-    ASSERT(mon->type == MON_ORIGIN);
-    ASSERT(is_internal_pid(mon->u.pid));
-    ASSERT(is_internal_ref(mon->ref));
+static ERTS_INLINE int
+rmon_is_dying(ErtsResourceMonitors *rms)
+{
+    return !!(rms->refc & ERTS_RESOURCE_DYING_FLAG);
+}
 
-    if (ctx->scheduler > 0) { /* Normal scheduler */
-        rp = erts_proc_lookup(mon->u.pid);
-    }
-    else {
-        rp = erts_proc_lookup_inc_refc(mon->u.pid);
-    }
+static ERTS_INLINE void
+rmon_refc_inc(ErtsResourceMonitors *rms)
+{
+    rms->refc++;
+}
 
-    if (!rp) {
-        is_exiting = 1;
-    }
-    if (rp) {
-        erts_proc_lock(rp, ERTS_PROC_LOCK_LINK);
-        if (ERTS_PROC_IS_EXITING(rp)) {
-            is_exiting = 1;
-        } else {
-            rmon = erts_remove_monitor(&ERTS_P_MONITORS(rp), mon->ref);
-            ASSERT(rmon);
-            is_exiting = 0;
-        }
-        erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-        if (ctx->scheduler <= 0)
-            erts_proc_dec_refc(rp);
-    }
-    if (is_exiting) {
-        ctx->resource->monitors->pending_failed_fire++;
-    }
+static ERTS_INLINE Uint
+rmon_refc_dec_read(ErtsResourceMonitors *rms)
+{
+    Uint res;
+    ASSERT((rms->refc & ERTS_RESOURCE_REFC_MASK) != 0);
+    res = --rms->refc;
+    return res & ERTS_RESOURCE_REFC_MASK;
+}
 
-    /* ToDo: Delay destruction after monitor_locks */
-    if (rmon) {
-        ASSERT(rmon->type == MON_NIF_TARGET);
-        ASSERT(rmon->u.resource == ctx->resource);
-        erts_destroy_monitor(rmon);
-    }
-    erts_destroy_monitor(mon);
+static ERTS_INLINE void
+rmon_refc_dec(ErtsResourceMonitors *rms)
+{
+    ASSERT((rms->refc & ERTS_RESOURCE_REFC_MASK) != 0);
+    --rms->refc;
 }
 
-static void destroy_all_monitors(ErtsMonitor* monitors, ErtsResource* resource)
+static ERTS_INLINE Uint
+rmon_refc_read(ErtsResourceMonitors *rms)
 {
-    struct destroy_monitor_ctx ctx;
+    return rms->refc & ERTS_RESOURCE_REFC_MASK;
+}
 
-    execution_state(NULL, NULL, &ctx.scheduler);
+static void dtor_demonitor(ErtsMonitor* mon, void* context)
+{
+    ASSERT(erts_monitor_is_origin(mon));
+    ASSERT(is_internal_pid(mon->other.item));
 
-    ctx.resource = resource;
-    erts_sweep_monitors(monitors, &destroy_one_monitor, &ctx);
+    erts_proc_sig_send_demonitor(mon);
 }
 
-
 #  define NIF_RESOURCE_DTOR &nif_resource_dtor
 
 static int nif_resource_dtor(Binary* bin)
@@ -2281,34 +2274,36 @@ static int nif_resource_dtor(Binary* bin)
 
     if (resource->monitors) {
         ErtsResourceMonitors* rm = resource->monitors;
+        int kill;
+        ErtsMonitor *root;
+        Uint refc;
 
         ASSERT(type->down);
         erts_mtx_lock(&rm->lock);
         ASSERT(erts_refc_read(&bin->intern.refc, 0) == 0);
-        if (rm->root) {
-            ASSERT(!rm->is_dying);
-            destroy_all_monitors(rm->root, resource);
+        kill = !rmon_is_dying(rm);
+        if (kill) {
+            rmon_set_dying(rm);
+            root = rm->root;
             rm->root = NULL;
         }
-        if (rm->pending_failed_fire) {
-            /*
-             * Resource death struggle prolonged to serve exiting process(es).
-             * Destructor will be called again when last exiting process
-             * tries to fire its MON_NIF_TARGET monitor (and fails).
-             *
-             * This resource is doomed. It has no "real" references and
-             * should get not get called upon to do anything except the
-             * final destructor call.
-             *
-             * We keep refc at 0 and use a separate counter for exiting
-             * processes to avoid resource getting revived by "dec_term".
-             */
-            ASSERT(!rm->is_dying);
-            rm->is_dying = 1;
-            erts_mtx_unlock(&rm->lock);
-            return 0;
-        }
+        refc = rmon_refc_read(rm);
         erts_mtx_unlock(&rm->lock);
+
+        if (kill)
+            erts_monitor_tree_foreach_delete(&root,
+                                             dtor_demonitor,
+                                             NULL);
+
+        /*
+         * If resource->monitors->refc != 0 there are
+         * outstanding references to the resource from
+         * monitors that has not been removed yet.
+         * nif_resource_dtor() will be called again this
+         * reference count reach zero.
+         */
+        if (refc != 0)
+            return 0; /* we'll be back... */
         erts_mtx_destroy(&rm->lock);
     }
 
@@ -2338,54 +2333,82 @@ void erts_resource_stop(ErtsResource* resource, ErlNifEvent e,
     post_nif_noproc(&msg_env);
 }
 
-void erts_fire_nif_monitor(ErtsResource* resource, Eterm pid, Eterm ref)
+void erts_nif_demonitored(ErtsResource* resource)
 {
-    ErtsMonitor* rmon;
+    ErtsResourceMonitors* rmp = resource->monitors;
     ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource);
+    int free_me;
+
+    ASSERT(rmp);
+    ASSERT(resource->type->down);
+
+    erts_mtx_lock(&rmp->lock);
+    free_me = ((rmon_refc_dec_read(rmp) == 0) & !!rmon_is_dying(rmp));
+    erts_mtx_unlock(&rmp->lock);
+
+    if (free_me)
+        erts_bin_free(&bin->binary);
+}
+
+void erts_fire_nif_monitor(ErtsMonitor *tmon)
+{
+    ErtsResource* resource;
+    ErtsMonitorData *mdp;
+    ErtsMonitor *omon;
+    ErtsBinary* bin;
     struct enif_msg_environment_t msg_env;
     ErlNifPid nif_pid;
     ErlNifMonitor nif_monitor;
-    ErtsResourceMonitors* rmp = resource->monitors;
+    ErtsResourceMonitors* rmp;
+    Uint mrefc, brefc;
+    int active, is_dying;
+
+    ASSERT(tmon->type == ERTS_MON_TYPE_RESOURCE);
+    ASSERT(erts_monitor_is_target(tmon));
+
+    resource = tmon->other.ptr;
+    bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource);
+    rmp = resource->monitors;
+
+    mdp = erts_monitor_to_data(tmon);
+    omon = &mdp->origin;
 
     ASSERT(rmp);
     ASSERT(resource->type->down);
 
     erts_mtx_lock(&rmp->lock);
-    rmon = erts_remove_monitor(&rmp->root, ref);
-    if (!rmon) {
-        int free_me = (--rmp->pending_failed_fire == 0) && rmp->is_dying;
-        ASSERT(rmp->pending_failed_fire >= 0);
-        erts_mtx_unlock(&rmp->lock);
-
-        if (free_me) {
-            ASSERT(erts_refc_read(&bin->binary.intern.refc, 0) == 0);
-            erts_bin_free(&bin->binary);
-        }
-        return;
+
+    mrefc = rmon_refc_dec_read(rmp);
+    is_dying = rmon_is_dying(rmp);
+    active = !is_dying && erts_monitor_is_in_table(omon);
+
+    if (active) {
+        erts_monitor_tree_delete(&rmp->root, omon);
+        brefc = (Uint) erts_refc_inc_unless(&bin->binary.intern.refc, 0, 0);
     }
-    ASSERT(!rmp->is_dying);
-    if (erts_refc_inc_unless(&bin->binary.intern.refc, 0, 0) == 0) {
-        /*
-         * Racing resource destruction. 
-         * To avoid a more complex refc-dance with destructing thread
-         * we avoid calling 'down' and just silently remove the monitor.
-         * This can happen even for non smp as destructor calls may be scheduled.
-         */
-        erts_mtx_unlock(&rmp->lock);
+
+    erts_mtx_unlock(&rmp->lock);
+
+    if (!active) {
+        ASSERT(!is_dying || erts_refc_read(&bin->binary.intern.refc, 0) == 0);
+        if (is_dying && mrefc == 0)
+            erts_bin_free(&bin->binary);
+        erts_monitor_release(tmon);
     }
     else {
-        erts_mtx_unlock(&rmp->lock);
-
-        ASSERT(rmon->u.pid == pid);
-        erts_ref_to_driver_monitor(ref, &nif_monitor);
-        nif_pid.pid = pid;
-        pre_nif_noproc(&msg_env, resource->type->owner, NULL);
-        resource->type->down(&msg_env.env, resource->data, &nif_pid, &nif_monitor);
-        post_nif_noproc(&msg_env);
+        if (brefc > 0) {
+            ASSERT(is_internal_pid(omon->other.item));
+            erts_ref_to_driver_monitor(mdp->ref, &nif_monitor);
+            nif_pid.pid = omon->other.item;
+            pre_nif_noproc(&msg_env, resource->type->owner, NULL);
+            resource->type->down(&msg_env.env, resource->data, &nif_pid, &nif_monitor);
+            post_nif_noproc(&msg_env);
+
+            erts_bin_release(&bin->binary);
+        }
 
-        erts_bin_release(&bin->binary);
+        erts_monitor_release_both(mdp);
     }
-    erts_destroy_monitor(rmon);
 }
 
 void* enif_alloc_resource(ErlNifResourceType* type, size_t data_sz)
@@ -2422,8 +2445,7 @@ void* enif_alloc_resource(ErlNifResourceType* type, size_t data_sz)
         erts_mtx_init(&resource->monitors->lock, "resource_monitors", NIL,
             ERTS_LOCK_FLAGS_CATEGORY_GENERIC);
         resource->monitors->root = NULL;
-        resource->monitors->pending_failed_fire = 0;
-        resource->monitors->is_dying = 0;
+        resource->monitors->refc = 0;
         resource->monitors->user_data_sz = data_sz;
     }
     else {
@@ -2438,7 +2460,7 @@ void enif_release_resource(void* obj)
     ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource);
 
     ASSERT(ERTS_MAGIC_BIN_DESTRUCTOR(bin) == NIF_RESOURCE_DTOR);
-    ASSERT(!(resource->monitors && resource->monitors->is_dying));
+    ASSERT(erts_refc_read(&bin->binary.intern.refc, 0) != 0);
 #ifdef DEBUG
     erts_refc_dec(&resource->nif_refc, 0);
 #endif
@@ -2451,7 +2473,7 @@ void enif_keep_resource(void* obj)
     ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource);
 
     ASSERT(ERTS_MAGIC_BIN_DESTRUCTOR(bin) == NIF_RESOURCE_DTOR);
-    ASSERT(!(resource->monitors && resource->monitors->is_dying));
+    ASSERT(erts_refc_read(&bin->binary.intern.refc, 0) != 0);
 #ifdef DEBUG
     erts_refc_inc(&resource->nif_refc, 1);
 #endif
@@ -2461,7 +2483,7 @@ void enif_keep_resource(void* obj)
 Eterm erts_bld_resource_ref(Eterm** hpp, ErlOffHeap* oh, ErtsResource* resource)
 {
     ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource);
-    ASSERT(!(resource->monitors && resource->monitors->is_dying));
+    ASSERT(erts_refc_read(&bin->binary.intern.refc, 0) != 0);
     return erts_mk_magic_ref(hpp, oh, &bin->binary);
 }
 
@@ -2470,7 +2492,7 @@ ERL_NIF_TERM enif_make_resource(ErlNifEnv* env, void* obj)
     ErtsResource* resource = DATA_TO_RESOURCE(obj);
     ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource);
     Eterm* hp = alloc_heap(env, ERTS_MAGIC_REF_THING_SIZE);
-    ASSERT(!(resource->monitors && resource->monitors->is_dying));
+    ASSERT(erts_refc_read(&bin->binary.intern.refc, 0) != 0);
     return erts_mk_magic_ref(&hp, &MSO(env->proc), &bin->binary);
 }
 
@@ -3150,123 +3172,88 @@ int enif_map_iterator_get_pair(ErlNifEnv *env,
 int enif_monitor_process(ErlNifEnv* env, void* obj, const ErlNifPid* target_pid,
                          ErlNifMonitor* monitor)
 {
-    int scheduler;
     ErtsResource* rsrc = DATA_TO_RESOURCE(obj);
-    Process *rp;
     Eterm tmp[ERTS_REF_THING_SIZE];
     Eterm ref;
-    int retval;
+    ErtsResourceMonitors *rm;
+    ErtsMonitorData *mdp;
 
     ASSERT(ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(rsrc)->magic_binary.destructor
            == NIF_RESOURCE_DTOR);
-    ASSERT(!(rsrc->monitors && rsrc->monitors->is_dying));
+    ASSERT(erts_refc_read(&ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(rsrc)->binary.intern.refc, 0) != 0);
     ASSERT(!rsrc->monitors == !rsrc->type->down);
 
-
-    if (!rsrc->monitors) {
+    rm = rsrc->monitors;
+    if (!rm) {
         ASSERT(!rsrc->type->down);
         return -1;
     }
     ASSERT(rsrc->type->down);
 
-    execution_state(env, NULL, &scheduler);
+    ref = erts_make_ref_in_buffer(tmp);
 
-    if (scheduler > 0) /* Normal scheduler */
-        rp = erts_proc_lookup_raw(target_pid->pid);
-    else
-        rp = erts_proc_lookup_raw_inc_refc(target_pid->pid);
+    mdp = erts_monitor_create(ERTS_MON_TYPE_RESOURCE, ref,
+                              (Eterm) rsrc, target_pid->pid, NIL);
+    erts_mtx_lock(&rm->lock);
+    ASSERT(!rmon_is_dying(rm));
+    erts_monitor_tree_insert(&rm->root, &mdp->origin);
+    rmon_refc_inc(rm);
+    erts_mtx_unlock(&rm->lock);
 
-    if (!rp)
-        return 1;
+    if (!erts_proc_sig_send_monitor(&mdp->target, target_pid->pid)) {
+        /* Failed to send monitor signal; cleanup... */
+#ifdef DEBUG
+        ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(rsrc);
+#endif
 
-    ref = erts_make_ref_in_buffer(tmp);
+        erts_mtx_lock(&rm->lock);
+        ASSERT(!rmon_is_dying(rm));
+        erts_monitor_tree_delete(&rm->root, &mdp->origin);
+        rmon_refc_dec(rm);
+        ASSERT(erts_refc_read(&bin->binary.intern.refc, 1) != 0);
+        erts_mtx_unlock(&rm->lock);
+        erts_monitor_release_both(mdp);
 
-    erts_mtx_lock(&rsrc->monitors->lock);
-    erts_proc_lock(rp, ERTS_PROC_LOCK_LINK);
-    if (ERTS_PSFLG_FREE & erts_atomic32_read_nob(&rp->state)) {
-        retval = 1;
-    }
-    else {
-        erts_add_monitor(&rsrc->monitors->root, MON_ORIGIN, ref, rp->common.id, NIL);
-        erts_add_monitor(&ERTS_P_MONITORS(rp), MON_NIF_TARGET, ref, (UWord)rsrc, NIL);
-        retval = 0;
+        return 1;
     }
-    erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-    erts_mtx_unlock(&rsrc->monitors->lock);
 
-    if (scheduler <= 0)
-        erts_proc_dec_refc(rp);
     if (monitor)
         erts_ref_to_driver_monitor(ref,monitor);
 
-    return retval;
+    return 0;
 }
 
 int enif_demonitor_process(ErlNifEnv* env, void* obj, const ErlNifMonitor* monitor)
 {
-    int scheduler;
     ErtsResource* rsrc = DATA_TO_RESOURCE(obj);
 #ifdef DEBUG
     ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(rsrc);
 #endif
-    Process *rp;
+    ErtsResourceMonitors *rm;
     ErtsMonitor *mon;
-    ErtsMonitor *rmon = NULL;
     Eterm ref_heap[ERTS_REF_THING_SIZE];
     Eterm ref;
-    int is_exiting;
 
     ASSERT(bin->magic_binary.destructor == NIF_RESOURCE_DTOR);
-    ASSERT(!(rsrc->monitors && rsrc->monitors->is_dying));
-
-    execution_state(env, NULL, &scheduler);
+    ASSERT(erts_refc_read(&bin->binary.intern.refc, 0) != 0);
 
     ref = erts_driver_monitor_to_ref(ref_heap, monitor);
 
-    erts_mtx_lock(&rsrc->monitors->lock);
-    mon = erts_remove_monitor(&rsrc->monitors->root, ref);
+    rm = rsrc->monitors;
+    erts_mtx_lock(&rm->lock);
+    ASSERT(!rmon_is_dying(rm));
+    mon = erts_monitor_tree_lookup(rm->root, ref);
+    if (mon)
+        erts_monitor_tree_delete(&rm->root, mon);
+    erts_mtx_unlock(&rm->lock);
 
-    if (mon == NULL) {
-        erts_mtx_unlock(&rsrc->monitors->lock);
+    if (!mon)
         return 1;
-    }
-
-    ASSERT(mon->type == MON_ORIGIN);
-    ASSERT(is_internal_pid(mon->u.pid));
-
-    if (scheduler > 0) /* Normal scheduler */
-        rp = erts_proc_lookup(mon->u.pid);
-    else
-        rp = erts_proc_lookup_inc_refc(mon->u.pid);
-
-    if (!rp) {
-        is_exiting = 1;
-    }
-    else {
-        erts_proc_lock(rp, ERTS_PROC_LOCK_LINK);
-        if (ERTS_PROC_IS_EXITING(rp)) {
-            is_exiting = 1;
-        } else {
-            rmon = erts_remove_monitor(&ERTS_P_MONITORS(rp), ref);
-            ASSERT(rmon);
-            is_exiting = 0;
-        }
-        erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
 
-        if (scheduler <= 0)
-            erts_proc_dec_refc(rp);
-    }
-    if (is_exiting) {
-        rsrc->monitors->pending_failed_fire++;
-    }
-    erts_mtx_unlock(&rsrc->monitors->lock);
+    ASSERT(erts_monitor_is_origin(mon));
+    ASSERT(is_internal_pid(mon->other.item));
 
-    if (rmon) {
-        ASSERT(rmon->type == MON_NIF_TARGET);
-        ASSERT(rmon->u.resource == rsrc);
-        erts_destroy_monitor(rmon);
-    }
-    erts_destroy_monitor(mon);
+    erts_proc_sig_send_demonitor(mon);
 
     return 0;
 }
diff --git a/erts/emulator/beam/erl_node_container_utils.h b/erts/emulator/beam/erl_node_container_utils.h
index 6ec428e282..99e938266b 100644
--- a/erts/emulator/beam/erl_node_container_utils.h
+++ b/erts/emulator/beam/erl_node_container_utils.h
@@ -318,5 +318,3 @@ extern ErtsPTab erts_port;
 #define is_not_ref(x)			(!is_ref(x))
 
 #endif
-
-
diff --git a/erts/emulator/beam/erl_node_tables.c b/erts/emulator/beam/erl_node_tables.c
index e8901a652f..ca83e70046 100644
--- a/erts/emulator/beam/erl_node_tables.c
+++ b/erts/emulator/beam/erl_node_tables.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2001-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2001-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -31,6 +31,7 @@
 #include "dtrace-wrapper.h"
 #include "erl_binary.h"
 #include "erl_bif_unique.h"
+#include "erl_proc_sig_queue.h"
 
 Hash erts_dist_table;
 Hash erts_node_table;
@@ -174,11 +175,7 @@ dist_table_alloc(void *dep_tmpl)
     dep->flags				= 0;
     dep->version			= 0;
 
-    erts_mtx_init(&dep->lnk_mtx, "dist_entry_links", sysname,
-        ERTS_LOCK_FLAGS_CATEGORY_DISTRIBUTION);
-    dep->node_links			= NULL;
-    dep->nlinks				= NULL;
-    dep->monitors			= NULL;
+    dep->mld                            = NULL;
 
     erts_mtx_init(&dep->qlock, "dist_entry_out_queue", sysname,
         ERTS_LOCK_FLAGS_CATEGORY_DISTRIBUTION);
@@ -225,9 +222,7 @@ dist_table_free(void *vdep)
     ASSERT(de_refc_read(dep, -1) == -1);
     ASSERT(dep->state == ERTS_DE_STATE_IDLE);
     ASSERT(is_nil(dep->cid));
-    ASSERT(dep->nlinks == NULL);
-    ASSERT(dep->node_links == NULL);
-    ASSERT(dep->monitors == NULL);
+    ASSERT(dep->mld == NULL);
 
     /* Link out */
 
@@ -250,7 +245,6 @@ dist_table_free(void *vdep)
 
     ASSERT(!dep->cache);
     erts_rwmtx_destroy(&dep->rwmtx);
-    erts_mtx_destroy(&dep->lnk_mtx);
     erts_mtx_destroy(&dep->qlock);
 
 #ifdef DEBUG
@@ -606,7 +600,9 @@ erts_set_dist_entry_not_connected(DistEntry *dep)
 void
 erts_set_dist_entry_pending(DistEntry *dep)
 {
+    ErtsMonLnkDist *mld = erts_mon_link_dist_create(dep->sysname);
     ERTS_LC_ASSERT(erts_lc_is_de_rwlocked(dep));
+    
     erts_rwmtx_rwlock(&erts_dist_table_rwmtx);
 
     ASSERT(dep != erts_this_dist_entry);
@@ -631,6 +627,10 @@ erts_set_dist_entry_pending(DistEntry *dep)
     dep->flags = (DFLAG_DIST_MANDATORY | DFLAG_DIST_HOPEFULLY | DFLAG_NO_MAGIC);
     dep->connection_id = (dep->connection_id + 1) & ERTS_DIST_CON_ID_MASK;
 
+    ASSERT(!dep->mld);
+    mld->connection_id = dep->connection_id;
+    dep->mld = mld;
+
     dep->prev = NULL;
     dep->next = erts_pending_dist_entries;
     if(erts_pending_dist_entries) {
@@ -647,6 +647,8 @@ erts_set_dist_entry_connected(DistEntry *dep, Eterm cid, Uint flags)
 {
     erts_aint32_t set_qflgs;
 
+    ASSERT(dep->mld);
+
     ERTS_LC_ASSERT(erts_lc_is_de_rwlocked(dep));
     erts_rwmtx_rwlock(&erts_dist_table_rwmtx);
 
@@ -1099,6 +1101,7 @@ static Eterm AM_system;
 static Eterm AM_timer;
 static Eterm AM_delayed_delete_timer;
 static Eterm AM_thread_progress_delete_timer;
+static Eterm AM_signal;
 
 static void setup_reference_table(void);
 static Eterm reference_table_term(Uint **hpp, ErlOffHeap *ohp, Uint *szp);
@@ -1120,6 +1123,7 @@ typedef struct node_referrer_ {
     int bin_ref;
     int timer_ref;
     int system_ref;
+    int signal_ref;
     Eterm id;
     Uint id_heap[ID_HEAP_SIZE];
     ErlOffHeap off_heap;
@@ -1137,6 +1141,7 @@ typedef struct dist_referrer_ {
     int node_ref;
     int ctrl_ref;
     int system_ref;
+    int signal_ref;
     Eterm id;
     Uint creation;
     Uint id_heap[ID_HEAP_SIZE];
@@ -1190,6 +1195,7 @@ erts_get_node_and_dist_references(struct process *proc)
 	INIT_AM(system);
 	INIT_AM(delayed_delete_timer);
         INIT_AM(thread_progress_delete_timer);
+	INIT_AM(signal);
 	references_atoms_need_init = 0;
     }
 
@@ -1226,6 +1232,7 @@ erts_get_node_and_dist_references(struct process *proc)
 #define MONITOR_REF 7
 #define TIMER_REF 8
 #define SYSTEM_REF 9
+#define SIGNAL_REF 10
 
 #define INC_TAB_SZ 10
 
@@ -1260,6 +1267,7 @@ insert_dist_referrer(ReferredDist *referred_dist,
 	drp->node_ref = 0;
 	drp->ctrl_ref = 0;
 	drp->system_ref = 0;
+        drp->signal_ref = 0;
     }
 
     switch (type) {
@@ -1268,6 +1276,7 @@ insert_dist_referrer(ReferredDist *referred_dist,
     case HEAP_REF:	drp->heap_ref++;	break;
     case ETS_REF:	drp->ets_ref++;	        break;
     case SYSTEM_REF:	drp->system_ref++;	break;
+    case SIGNAL_REF:	drp->signal_ref++;	break;
     default:		ASSERT(0);
     }
 }
@@ -1321,6 +1330,7 @@ insert_node_referrer(ReferredNode *referred_node, int type, Eterm id)
 	nrp->bin_ref = 0;
 	nrp->timer_ref = 0;
 	nrp->system_ref = 0;
+	nrp->signal_ref = 0;
     }
 
     switch (type) {
@@ -1331,6 +1341,7 @@ insert_node_referrer(ReferredNode *referred_node, int type, Eterm id)
     case MONITOR_REF:   nrp->monitor_ref++;     break;
     case TIMER_REF:	nrp->timer_ref++;	break;
     case SYSTEM_REF:	nrp->system_ref++;	break;
+    case SIGNAL_REF:	nrp->signal_ref++;	break;
     default:		ASSERT(0);
     }
 }
@@ -1438,49 +1449,145 @@ insert_offheap(ErlOffHeap *oh, int type, Eterm id)
     }
 }
 
-static void doit_insert_monitor(ErtsMonitor *monitor, void *p)
+static void insert_monitor_data(ErtsMonitor *mon, int type, Eterm id)
+{
+    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
+    if ((mdp->origin.flags & (ERTS_ML_FLG_DBG_VISITED
+                              | ERTS_ML_FLG_EXTENDED)) == ERTS_ML_FLG_EXTENDED) {
+        if (mon->type != ERTS_MON_TYPE_NODE) {
+            ErtsMonitorDataExtended *mdep = (ErtsMonitorDataExtended *) mdp;
+            ASSERT(mon->flags & ERTS_ML_FLG_EXTENDED);
+            if (mdep->uptr.ohhp) {
+                ErlOffHeap oh;
+                ERTS_INIT_OFF_HEAP(&oh);
+                oh.first = mdep->uptr.ohhp;
+                insert_offheap(&oh, type, id);
+            }
+        }
+    }
+    mdp->origin.flags |= ERTS_ML_FLG_DBG_VISITED;
+}
+
+static void insert_monitor(ErtsMonitor *mon, void *idp)
+{
+    Eterm id = *((Eterm *) idp);
+    insert_monitor_data(mon, MONITOR_REF, id);
+}
+
+static void clear_visited_monitor(ErtsMonitor *mon, void *p)
+{
+    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
+    mdp->origin.flags &= ~ERTS_ML_FLG_DBG_VISITED;
+}
+
+static void
+insert_p_monitors(ErtsPTabElementCommon *p)
+{
+    Eterm id = p->id;
+    erts_monitor_tree_foreach(p->u.alive.monitors,
+                              insert_monitor,
+                              (void *) &id);
+    erts_monitor_list_foreach(p->u.alive.lt_monitors,
+                              insert_monitor,
+                              (void *) &id);
+}
+
+static void
+insert_dist_monitors(DistEntry *dep)
+{
+    if (dep->mld) {
+        erts_monitor_list_foreach(dep->mld->monitors,
+                                  insert_monitor,
+                                  (void *) &dep->sysname);
+        erts_monitor_tree_foreach(dep->mld->orig_name_monitors,
+                                  insert_monitor,
+                                  (void *) &dep->sysname);
+    }
+}
+
+static void
+clear_visited_p_monitors(ErtsPTabElementCommon *p)
+{
+    erts_monitor_tree_foreach(p->u.alive.monitors,
+                              clear_visited_monitor,
+                              NULL);
+    erts_monitor_list_foreach(p->u.alive.lt_monitors,
+                              clear_visited_monitor,
+                              NULL);
+}
+
+static void
+clear_visited_dist_monitors(DistEntry *dep)
+{
+    if (dep->mld) {
+        erts_monitor_list_foreach(dep->mld->monitors,
+                                  clear_visited_monitor,
+                                  NULL);
+        erts_monitor_tree_foreach(dep->mld->orig_name_monitors,
+                                  clear_visited_monitor,
+                                  NULL);
+    }
+}
+
+static void insert_link_data(ErtsLink *lnk, int type, Eterm id)
 {
-    Eterm *idp = p;
-    if(monitor->type != MON_NIF_TARGET && is_external(monitor->u.pid))
-	insert_node(external_thing_ptr(monitor->u.pid)->node, MONITOR_REF, *idp);
-    if(is_external(monitor->ref))
-	insert_node(external_thing_ptr(monitor->ref)->node, MONITOR_REF, *idp);
+    ErtsLinkData *ldp = erts_link_to_data(lnk);
+    if ((ldp->a.flags & (ERTS_ML_FLG_DBG_VISITED
+                         | ERTS_ML_FLG_EXTENDED)) == ERTS_ML_FLG_EXTENDED) {
+        ErtsLinkDataExtended *ldep = (ErtsLinkDataExtended *) ldp;
+        if (ldep->ohhp) {
+            ErlOffHeap oh;
+            ERTS_INIT_OFF_HEAP(&oh);
+            oh.first = ldep->ohhp;
+            insert_offheap(&oh, type, id);
+        }
+    }
+    ldp->a.flags |= ERTS_ML_FLG_DBG_VISITED;
 }
 
-static void doit_insert_link(ErtsLink *lnk, void *p)
+static void insert_link(ErtsLink *lnk, void *idp)
 {
-    Eterm *idp = p;
-    if(is_external(lnk->pid))
-	insert_node(external_thing_ptr(lnk->pid)->node, LINK_REF, 
-		    *idp);
+    Eterm id = *((Eterm *) idp);
+    insert_link_data(lnk, LINK_REF, id);
 }
 
+static void clear_visited_link(ErtsLink *lnk, void *p)
+{
+    ErtsLinkData *ldp = erts_link_to_data(lnk);
+    ldp->a.flags &= ~ERTS_ML_FLG_DBG_VISITED;
+}
 
 static void
-insert_monitors(ErtsMonitor *monitors, Eterm id)
+insert_p_links(ErtsPTabElementCommon *p)
 {
-    erts_doforall_monitors(monitors,&doit_insert_monitor,&id);
+    Eterm id = p->id;
+    erts_link_tree_foreach(p->u.alive.links, insert_link, (void *) &id);
 }
 
 static void
-insert_links(ErtsLink *lnk, Eterm id)
+insert_dist_links(DistEntry *dep)
 {
-    erts_doforall_links(lnk,&doit_insert_link,&id);
+    if (dep->mld)
+        erts_link_list_foreach(dep->mld->links,
+                               insert_link,
+                               (void *) &dep->sysname);
 }
 
-static void doit_insert_link2(ErtsLink *lnk, void *p)
+static void
+clear_visited_p_links(ErtsPTabElementCommon *p)
 {
-    Eterm *idp = p;
-    if(is_external(lnk->pid))
-	insert_node(external_thing_ptr(lnk->pid)->node, LINK_REF, 
-		    *idp);
-    insert_links(ERTS_LINK_ROOT(lnk), *idp);
+    erts_link_tree_foreach(p->u.alive.links,
+                           clear_visited_link,
+                           NULL);
 }
 
 static void
-insert_links2(ErtsLink *lnk, Eterm id)
+clear_visited_dist_links(DistEntry *dep)
 {
-    erts_doforall_links(lnk,&doit_insert_link2,&id);
+    if (dep->mld)
+        erts_link_list_foreach(dep->mld->links,
+                               clear_visited_link,
+                               NULL);
 }
 
 static void
@@ -1576,6 +1683,60 @@ insert_delayed_delete_dist_entry(void *state,
 }
 
 static void
+insert_message(ErtsMessage *msg, int type, Process *proc)
+{
+    ErlHeapFragment *heap_frag = NULL;
+
+    ASSERT(ERTS_SIG_IS_MSG(msg));
+    if (msg->data.attached) {
+        if (msg->data.attached == ERTS_MSG_COMBINED_HFRAG)
+            heap_frag = &msg->hfrag;
+        else if (ERTS_SIG_IS_INTERNAL_MSG(msg))
+            heap_frag = msg->data.heap_frag;
+        else {
+            if (msg->data.dist_ext->dep)
+                insert_dist_entry(msg->data.dist_ext->dep,
+                                  type, proc->common.id, 0);
+            if (is_not_nil(ERL_MESSAGE_TOKEN(msg)))
+                heap_frag = erts_dist_ext_trailer(msg->data.dist_ext);
+        }
+    }
+    while (heap_frag) {
+        insert_offheap(&(heap_frag->off_heap),
+                       type,
+                       proc->common.id);
+        heap_frag = heap_frag->next;
+    }
+}
+
+static void
+insert_sig_msg(ErtsMessage *msg, void *arg)
+{
+    insert_message(msg, SIGNAL_REF, (Process *) arg);
+}
+
+static void
+insert_sig_offheap(ErlOffHeap *ohp, void *arg)
+{
+    Process *proc = arg;
+    insert_offheap(ohp, SIGNAL_REF, proc->common.id);
+}
+
+static void
+insert_sig_monitor(ErtsMonitor *mon, void *arg)
+{
+    Process *proc = arg;
+    insert_monitor_data(mon, SIGNAL_REF, proc->common.id);
+}
+
+static void
+insert_sig_link(ErtsLink *lnk, void *arg)
+{
+    Process *proc = arg;
+    insert_link_data(lnk, SIGNAL_REF, proc->common.id);
+}
+
+static void
 setup_reference_table(void)
 {
     ErlHeapFragment *hfp;
@@ -1630,10 +1791,7 @@ setup_reference_table(void)
 	Process *proc = erts_pix2proc(i);
 	if (proc) {
 	    int mli;
-	    ErtsMessage *msg_list[] = {
-		proc->msg.first,
-		proc->msg_inq.first,
-		proc->msg_frag};
+	    ErtsMessage *msg_list[] = {proc->msg_frag};
 
 	    /* Insert Heap */
 	    insert_offheap(&(proc->off_heap),
@@ -1648,34 +1806,24 @@ setup_reference_table(void)
 	    /* Insert msg buffers */
 	    for (mli = 0; mli < sizeof(msg_list)/sizeof(msg_list[0]); mli++) {
 		ErtsMessage *msg;
-		for (msg = msg_list[mli]; msg; msg = msg->next) {
-		    ErlHeapFragment *heap_frag = NULL;
-		    if (msg->data.attached) {
-			if (msg->data.attached == ERTS_MSG_COMBINED_HFRAG)
-			    heap_frag = &msg->hfrag;
-			else if (is_value(ERL_MESSAGE_TERM(msg)))
-			    heap_frag = msg->data.heap_frag;
-			else {
-			    if (msg->data.dist_ext->dep)
-				insert_dist_entry(msg->data.dist_ext->dep,
-						  HEAP_REF, proc->common.id, 0);
-			    if (is_not_nil(ERL_MESSAGE_TOKEN(msg)))
-				heap_frag = erts_dist_ext_trailer(msg->data.dist_ext);
-			}
-		    }
-		    while (heap_frag) {
-			insert_offheap(&(heap_frag->off_heap),
-				       HEAP_REF,
-				       proc->common.id);
-			heap_frag = heap_frag->next;
-		    }
-		}
+		for (msg = msg_list[mli]; msg; msg = msg->next)
+                    insert_message(msg, HEAP_REF, proc);
 	    }
+
+            /* Insert signal queue */
+            erts_proc_sig_debug_foreach_sig(proc,
+                                            insert_sig_msg,
+                                            insert_sig_offheap,
+                                            insert_sig_monitor,
+                                            insert_sig_link,
+                                            (void *) proc);
+
 	    /* Insert links */
-	    if (ERTS_P_LINKS(proc))
-		insert_links(ERTS_P_LINKS(proc), proc->common.id);
-	    if (ERTS_P_MONITORS(proc))
-		insert_monitors(ERTS_P_MONITORS(proc), proc->common.id);
+            insert_p_links(&proc->common);
+
+            /* Insert monitors */
+            insert_p_monitors(&proc->common);
+
             {
                 DistEntry *dep = ERTS_PROC_GET_DIST_ENTRY(proc);
                 if (dep)
@@ -1705,11 +1853,9 @@ setup_reference_table(void)
 	    continue;
 
 	/* Insert links */
-	if (ERTS_P_LINKS(prt))
-	    insert_links(ERTS_P_LINKS(prt), prt->common.id);
+        insert_p_links(&prt->common);
 	/* Insert monitors */
-	if (ERTS_P_MONITORS(prt))
-	    insert_monitors(ERTS_P_MONITORS(prt), prt->common.id);
+        insert_p_monitors(&prt->common);
 	/* Insert port data */
 	ohp = erts_port_data_offheap(prt);
 	if (ohp)
@@ -1758,41 +1904,25 @@ setup_reference_table(void)
     /* Insert all dist links */
 
     for(dep = erts_visible_dist_entries; dep; dep = dep->next) {
-	if(dep->nlinks)
-	    insert_links2(dep->nlinks, dep->sysname);
-	if(dep->node_links)
-	    insert_links(dep->node_links, dep->sysname);
-	if(dep->monitors)
-	    insert_monitors(dep->monitors, dep->sysname);
+        insert_dist_links(dep);
+        insert_dist_monitors(dep);
     }
 
     for(dep = erts_hidden_dist_entries; dep; dep = dep->next) {
-	if(dep->nlinks)
-	    insert_links2(dep->nlinks, dep->sysname);
-	if(dep->node_links)
-	    insert_links(dep->node_links, dep->sysname);
-	if(dep->monitors)
-	    insert_monitors(dep->monitors, dep->sysname);
+        insert_dist_links(dep);
+        insert_dist_monitors(dep);
     }
 
     for(dep = erts_pending_dist_entries; dep; dep = dep->next) {
-        if(dep->nlinks)
-            insert_links2(dep->nlinks, dep->sysname);
-        if(dep->node_links)
-            insert_links(dep->node_links, dep->sysname);
-        if(dep->monitors)
-            insert_monitors(dep->monitors, dep->sysname);
+        insert_dist_links(dep);
+        insert_dist_monitors(dep);
     }
 
     /* Not connected dist entries should not have any links,
        but inspect them anyway */
     for(dep = erts_not_connected_dist_entries; dep; dep = dep->next) {
-	if(dep->nlinks)
-	    insert_links2(dep->nlinks, dep->sysname);
-	if(dep->node_links)
-	    insert_links(dep->node_links, dep->sysname);
-	if(dep->monitors)
-	    insert_monitors(dep->monitors, dep->sysname);
+        insert_dist_links(dep);
+        insert_dist_monitors(dep);
     }
 
     /* Insert all ets tables */
@@ -1877,6 +2007,10 @@ reference_table_term(Uint **hpp, ErlOffHeap *ohp, Uint *szp)
 		tup = MK_2TUP(AM_system, MK_UINT(nrp->system_ref));
 		nrl = MK_CONS(tup, nrl);
 	    }
+	    if(nrp->signal_ref) {
+		tup = MK_2TUP(AM_signal, MK_UINT(nrp->signal_ref));
+		nrl = MK_CONS(tup, nrl);
+	    }
 
 	    nrid = nrp->id;
 	    if (!IS_CONST(nrp->id)) {
@@ -1900,24 +2034,25 @@ reference_table_term(Uint **hpp, ErlOffHeap *ohp, Uint *szp)
 	    }
 	    else if(is_internal_port(nrid)) {
 		ASSERT(!nrp->heap_ref && !nrp->ets_ref && !nrp->bin_ref
-		       && !nrp->timer_ref && !nrp->system_ref);
+		       && !nrp->timer_ref && !nrp->system_ref && !nrp->signal_ref);
 		tup = MK_2TUP(AM_port, nrid);
 	    }
 	    else if(nrp->ets_ref) {
 		ASSERT(!nrp->heap_ref && !nrp->link_ref && 
 		       !nrp->monitor_ref && !nrp->bin_ref
-		       && !nrp->timer_ref && !nrp->system_ref);
+		       && !nrp->timer_ref && !nrp->system_ref && !nrp->signal_ref);
 		tup = MK_2TUP(AM_ets, nrid);
 	    }
 	    else if(nrp->bin_ref) {
 		ASSERT(is_small(nrid) || is_big(nrid));
 		ASSERT(!nrp->heap_ref && !nrp->ets_ref && !nrp->link_ref && 
 		       !nrp->monitor_ref && !nrp->timer_ref
-		       && !nrp->system_ref);
+		       && !nrp->system_ref && !nrp->signal_ref);
 		tup = MK_2TUP(AM_match_spec, nrid);
 	    }
 	    else  {
-		ASSERT(!nrp->heap_ref && !nrp->ets_ref && !nrp->bin_ref);
+		ASSERT(!nrp->heap_ref && !nrp->ets_ref && !nrp->bin_ref
+                       && !nrp->signal_ref);
 		ASSERT(is_atom(nrid));
 		tup = MK_2TUP(AM_dist, nrid);
 	    }
@@ -1961,30 +2096,36 @@ reference_table_term(Uint **hpp, ErlOffHeap *ohp, Uint *szp)
 		tup = MK_2TUP(AM_system, MK_UINT(drp->system_ref));
 		drl = MK_CONS(tup, drl);
 	    }
+	    if(drp->signal_ref) {
+		tup = MK_2TUP(AM_signal, MK_UINT(drp->signal_ref));
+		drl = MK_CONS(tup, drl);
+	    }
 
 	    if (is_internal_pid(drp->id)) {
 		ASSERT(!drp->node_ref);
 		tup = MK_2TUP(AM_process, drp->id);
 	    }
 	    else if(is_internal_port(drp->id)) {
-		ASSERT(drp->ctrl_ref && !drp->node_ref);
+		ASSERT(drp->ctrl_ref && !drp->node_ref && !drp->signal_ref);
 		tup = MK_2TUP(AM_port, drp->id);
 	    }
 	    else if (is_tuple(drp->id)) {
 		Eterm *t;
 		ASSERT(drp->system_ref && !drp->node_ref
-		       && !drp->ctrl_ref && !drp->heap_ref && !drp->ets_ref);
+		       && !drp->ctrl_ref && !drp->heap_ref && !drp->ets_ref
+                       && !drp->signal_ref);
 		t = tuple_val(drp->id);
 		ASSERT(2 == arityval(t[0]));
 		tup = MK_2TUP(t[1], t[2]);
 	    }
 	    else if (drp->ets_ref) {
                 ASSERT(!drp->heap_ref && !drp->node_ref &&
-                       !drp->ctrl_ref && !drp->system_ref);
+                       !drp->ctrl_ref && !drp->system_ref
+                       && !drp->signal_ref);
                 tup = MK_2TUP(AM_ets, drp->id);
             }
-            else {
-		ASSERT(!drp->ctrl_ref && drp->node_ref);
+	    else {
+		ASSERT(!drp->ctrl_ref && drp->node_ref && !drp->signal_ref);
 		ASSERT(is_atom(drp->id));
 		tup = MK_2TUP(drp->id, MK_UINT(drp->creation));
 		tup = MK_2TUP(AM_node, tup);
@@ -2019,10 +2160,21 @@ reference_table_term(Uint **hpp, ErlOffHeap *ohp, Uint *szp)
 
 }
 
+static void noop_sig_msg(ErtsMessage *msg, void *arg)
+{
+
+}
+
+static void noop_sig_offheap(ErlOffHeap *oh, void *arg)
+{
+
+}
+
 static void
 delete_reference_table(void)
 {
-    Uint i;
+    DistEntry *dep;
+    int i, max;
     for(i = 0; i < no_referred_nodes; i++) {
 	NodeReferrer *nrp;
 	NodeReferrer *tnrp;
@@ -2054,6 +2206,60 @@ delete_reference_table(void)
 	inserted_bins = inserted_bins->next;
 	erts_free(ERTS_ALC_T_NC_TMP, (void *)ib);
     }
+
+    /* Cleanup... */
+
+    max = erts_ptab_max(&erts_proc);
+    for (i = 0; i < max; i++) {
+	Process *proc = erts_pix2proc(i);
+	if (proc) {
+            clear_visited_p_links(&proc->common);
+            clear_visited_p_monitors(&proc->common);
+            erts_proc_sig_debug_foreach_sig(proc,
+                                            noop_sig_msg,
+                                            noop_sig_offheap,
+                                            clear_visited_monitor,
+                                            clear_visited_link,
+                                            (void *) proc);
+        }
+    }
+
+    max = erts_ptab_max(&erts_port);
+    for (i = 0; i < max; i++) {
+	erts_aint32_t state;
+	Port *prt;
+
+	prt = erts_pix2port(i);
+	if (!prt)
+	    continue;
+
+	state = erts_atomic32_read_nob(&prt->state);
+	if (state & ERTS_PORT_SFLGS_DEAD)
+	    continue;
+
+        clear_visited_p_links(&prt->common);
+        clear_visited_p_monitors(&prt->common);
+    }
+
+    for(dep = erts_visible_dist_entries; dep; dep = dep->next) {
+        clear_visited_dist_links(dep);
+        clear_visited_dist_monitors(dep);
+    }
+
+    for(dep = erts_hidden_dist_entries; dep; dep = dep->next) {
+        clear_visited_dist_links(dep);
+        clear_visited_dist_monitors(dep);
+    }
+
+    for(dep = erts_pending_dist_entries; dep; dep = dep->next) {
+        clear_visited_dist_links(dep);
+        clear_visited_dist_monitors(dep);
+    }
+
+    for(dep = erts_not_connected_dist_entries; dep; dep = dep->next) {
+        clear_visited_dist_links(dep);
+        clear_visited_dist_monitors(dep);
+    }
 }
 
 void
diff --git a/erts/emulator/beam/erl_node_tables.h b/erts/emulator/beam/erl_node_tables.h
index 58279017c8..9a792b10b1 100644
--- a/erts/emulator/beam/erl_node_tables.h
+++ b/erts/emulator/beam/erl_node_tables.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2001-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2001-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,7 +18,17 @@
  * %CopyrightEnd%
  */
 
-#ifndef ERL_NODE_TABLES_H__
+#ifndef ERL_NODE_TABLES_BASIC__
+#define ERL_NODE_TABLES_BASIC__
+
+typedef struct dist_entry_ DistEntry;
+typedef struct ErtsDistOutputBuf_ ErtsDistOutputBuf;
+void erts_ref_dist_entry(DistEntry *dep);
+void erts_deref_dist_entry(DistEntry *dep);
+
+#endif
+
+#if !defined(ERL_NODE_TABLES_BASIC_ONLY) && !defined(ERL_NODE_TABLES_H__)
 #define ERL_NODE_TABLES_H__
 
 /*
@@ -42,14 +52,14 @@
 #include "sys.h"
 #include "hash.h"
 #include "erl_alloc.h"
-#include "erl_process.h"
-#include "erl_monitors.h"
 #define ERTS_PORT_TASK_ONLY_BASIC_TYPES__
 #include "erl_port_task.h"
 #undef ERTS_PORT_TASK_ONLY_BASIC_TYPES__
+#include "erl_process.h"
 #define ERTS_BINARY_TYPES_ONLY__
 #include "erl_binary.h"
 #undef ERTS_BINARY_TYPES_ONLY__
+#include "erl_monitor_link.h"
 
 #define ERTS_NODE_TAB_DELAY_GC_DEFAULT (60)
 #define ERTS_NODE_TAB_DELAY_GC_MAX (100*1000*1000)
@@ -82,7 +92,6 @@ enum dist_entry_state {
 #define ERTS_DIST_OUTPUT_BUF_DBG_PATTERN ((Uint) 0xf713f713)
 #endif
 
-typedef struct ErtsDistOutputBuf_ ErtsDistOutputBuf;
 struct ErtsDistOutputBuf_ {
 #ifdef DEBUG
     Uint dbg_pattern;
@@ -113,7 +122,7 @@ struct ErtsProcList_;
  *   unlock mutexes with higher numbers before mutexes with higher numbers.
  */
 
-typedef struct dist_entry_ {
+struct dist_entry_ {
     HashBucket hash_bucket;     /* Hash bucket */
     struct dist_entry_ *next;	/* Next entry in dist_table (not sorted) */
     struct dist_entry_ *prev;	/* Previous entry in dist_table (not sorted) */
@@ -130,18 +139,7 @@ typedef struct dist_entry_ {
 				   atom cache etc. */
     unsigned long version;	/* Protocol version */
 
-
-    erts_mtx_t lnk_mtx;         /* Protects node_links, nlinks, and
-				   monitors. */
-    ErtsLink *node_links;       /* In a dist entry, node links are kept 
-				   in a separate tree, while they are 
-				   colocted with the ordinary link tree
-				   for processes. It's not due to confusion,
-				   it's because the link tree for the dist 
-				   entry is in two levels, see erl_monitors.h 
-				*/
-    ErtsLink *nlinks;           /* Link tree with subtrees */
-    ErtsMonitor *monitors;      /* Monitor tree */
+    ErtsMonLnkDist *mld;        /* Monitors and links */
 
     erts_mtx_t qlock;           /* Protects qflgs and out_queue */
     erts_atomic32_t qflgs;
@@ -163,7 +161,7 @@ typedef struct dist_entry_ {
     ErtsThrPrgrLaterOp later_op;
 
     struct transcode_context* transcode_ctx;
-} DistEntry;
+};
 
 typedef struct erl_node_ {
   HashBucket hash_bucket;	/* Hash bucket */
@@ -219,16 +217,12 @@ int erts_dist_entry_destructor(Binary *bin);
 DistEntry *erts_dhandle_to_dist_entry(Eterm dhandle);
 Eterm erts_build_dhandle(Eterm **hpp, ErlOffHeap*, DistEntry*);
 Eterm erts_make_dhandle(Process *c_p, DistEntry *dep);
-void erts_ref_dist_entry(DistEntry *dep);
-void erts_deref_dist_entry(DistEntry *dep);
 
 ERTS_GLB_INLINE void erts_deref_node_entry(ErlNode *np);
 ERTS_GLB_INLINE void erts_de_rlock(DistEntry *dep);
 ERTS_GLB_INLINE void erts_de_runlock(DistEntry *dep);
 ERTS_GLB_INLINE void erts_de_rwlock(DistEntry *dep);
 ERTS_GLB_INLINE void erts_de_rwunlock(DistEntry *dep);
-ERTS_GLB_INLINE void erts_de_links_lock(DistEntry *dep);
-ERTS_GLB_INLINE void erts_de_links_unlock(DistEntry *dep);
 
 #if ERTS_GLB_INLINE_INCL_FUNC_DEF
 
@@ -264,18 +258,6 @@ erts_de_rwunlock(DistEntry *dep)
     erts_rwmtx_rwunlock(&dep->rwmtx);
 }
 
-ERTS_GLB_INLINE void
-erts_de_links_lock(DistEntry *dep)
-{
-    erts_mtx_lock(&dep->lnk_mtx);
-}
-
-ERTS_GLB_INLINE void
-erts_de_links_unlock(DistEntry *dep)
-{
-    erts_mtx_unlock(&dep->lnk_mtx);
-}
-
 #endif /* #if ERTS_GLB_INLINE_INCL_FUNC_DEF */
 
 void erts_debug_test_node_tab_delayed_delete(Sint64 millisecs);
diff --git a/erts/emulator/beam/erl_port.h b/erts/emulator/beam/erl_port.h
index 0d148ee048..2a98a6f00b 100644
--- a/erts/emulator/beam/erl_port.h
+++ b/erts/emulator/beam/erl_port.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2012-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2012-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -373,7 +373,7 @@ Eterm erts_request_io_bytes(Process *c_p);
 
 void print_port_info(Port *, fmtfn_t, void *);
 void erts_port_free(Port *);
-void erts_fire_port_monitor(Port *prt, Eterm ref);
+void erts_fire_port_monitor(Port *prt, ErtsMonitor *tmon);
 int erts_port_handle_xports(Port *);
 
 #if defined(ERTS_ENABLE_LOCK_CHECK)
@@ -887,20 +887,20 @@ struct ErtsProc2PortSigData_ {
 	    Eterm item;
 	} info;
 	struct {
-	    Eterm port;
-	    Eterm to;
+            Eterm port_id;
+	    ErtsLink *lnk;
 	} link;
 	struct {
-	    Eterm from;
+            Eterm port_id;
+	    ErtsLink *lnk;
 	} unlink;
         struct {
-            Eterm origin;   /* who receives monitor event, pid */
-            Eterm name;     /* either name for named monitor, or port id */
+            Eterm port_id;
+            ErtsMonitor *mon;
         } monitor;
         struct {
-            Eterm origin;   /* who is at the other end of the monitor, pid */
-            Eterm name;     /* port id */
-            Uint32 ref[ERTS_MAX_REF_NUMBERS]; /* box contents of a ref */
+            Eterm port_id;
+            ErtsMonitor *mon;
         } demonitor;
     } u;
 } ;
@@ -946,7 +946,6 @@ typedef int (*ErtsProc2PortSigCallback)(Port *,
 
 typedef enum {
     ERTS_PORT_OP_BADARG,
-    ERTS_PORT_OP_CALLER_EXIT,
     ERTS_PORT_OP_BUSY,
     ERTS_PORT_OP_BUSY_SCHEDULED,
     ERTS_PORT_OP_SCHEDULED,
@@ -982,32 +981,13 @@ ErtsPortOpResult erts_port_command(Process *, int, Port *, Eterm, Eterm *);
 ErtsPortOpResult erts_port_output(Process *, int, Port *, Eterm, Eterm, Eterm *);
 ErtsPortOpResult erts_port_exit(Process *, int, Port *, Eterm, Eterm, Eterm *);
 ErtsPortOpResult erts_port_connect(Process *, int, Port *, Eterm, Eterm, Eterm *);
-ErtsPortOpResult erts_port_link(Process *, Port *, Eterm, Eterm *);
-ErtsPortOpResult erts_port_unlink(Process *, Port *, Eterm, Eterm *);
+ErtsPortOpResult erts_port_link(Process *, Port *, ErtsLink *, Eterm *);
+ErtsPortOpResult erts_port_unlink(Process *, Port *, ErtsLink *, Eterm *);
 ErtsPortOpResult erts_port_control(Process *, Port *, unsigned int, Eterm, Eterm *);
 ErtsPortOpResult erts_port_call(Process *, Port *, unsigned int, Eterm, Eterm *);
 ErtsPortOpResult erts_port_info(Process *, Port *, Eterm, Eterm *);
-
-/* Creates monitor between Origin and Target. Ref must be initialized to
- * a reference (ref may be rewritten to be used to serve additionally as a
- * signal id). Name is atom if user monitors port by name or NIL */
-ErtsPortOpResult erts_port_monitor(Process *origin, Port *target, Eterm name,
-                                   Eterm *ref);
-
-typedef enum {
-    /* Normal demonitor rules apply with locking and reductions bump */
-    ERTS_PORT_DEMONITOR_NORMAL = 1,
-    /* Relaxed demonitor rules when process is about to die, which means that
-     * pid lookup won't work, locks won't work, no reductions bump. */
-    ERTS_PORT_DEMONITOR_ORIGIN_ON_DEATHBED = 2,
-} ErtsDemonitorMode;
-
-/* Removes monitor between origin and target, identified by ref.
- * origin_is_dying can be 0 (false, normal locking rules and reductions bump
- * apply) or 1 (true, in case when we avoid origin locking) */
-ErtsPortOpResult erts_port_demonitor(Process *origin, ErtsDemonitorMode mode,
-                                    Port *target, Eterm ref,
-                                    Eterm *trap_ref);
+ErtsPortOpResult erts_port_monitor(Process *, Port *, ErtsMonitor *);
+ErtsPortOpResult erts_port_demonitor(Process *, Port *, ErtsMonitor *);
 /* defined in erl_bif_port.c */
 Port *erts_sig_lookup_port(Process *c_p, Eterm id_or_name);
 
diff --git a/erts/emulator/beam/erl_proc_sig_queue.c b/erts/emulator/beam/erl_proc_sig_queue.c
new file mode 100644
index 0000000000..1b5cbb1919
--- /dev/null
+++ b/erts/emulator/beam/erl_proc_sig_queue.c
@@ -0,0 +1,3772 @@
+/*
+ * %CopyrightBegin%
+ * 
+ * Copyright Ericsson AB 2018. All Rights Reserved.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * 
+ * %CopyrightEnd%
+ */
+
+/*
+ * Description:	Process signal queue implementation.
+ *
+ * Author: 	Rickard Green
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include "sys.h"
+#include "global.h"
+#include "dist.h"
+#include "erl_process.h"
+#include "erl_port_task.h"
+#include "erl_trace.h"
+#include "beam_bp.h"
+#include "big.h"
+#include "erl_gc.h"
+#include "bif.h"
+#include "erl_proc_sig_queue.h"
+
+#define ERTS_SIG_REDS_CNT_FACTOR 4
+#define ERTS_PROC_SIG_TRACE_COUNT_LIMIT 200
+
+/*
+ * Note that not all signal are handled using this functionality!
+ */
+
+#define ERTS_SIG_Q_OP_MAX 9
+
+#define ERTS_SIG_Q_OP_EXIT                      0
+#define ERTS_SIG_Q_OP_EXIT_LINKED               1
+#define ERTS_SIG_Q_OP_MONITOR_DOWN              2
+#define ERTS_SIG_Q_OP_MONITOR                   3
+#define ERTS_SIG_Q_OP_DEMONITOR                 4
+#define ERTS_SIG_Q_OP_LINK                      5
+#define ERTS_SIG_Q_OP_UNLINK                    6
+#define ERTS_SIG_Q_OP_GROUP_LEADER              7
+#define ERTS_SIG_Q_OP_TRACE_CHANGE_STATE        8
+#define ERTS_SIG_Q_OP_PERSISTENT_MON_MSG        ERTS_SIG_Q_OP_MAX
+
+#define ERTS_SIG_Q_TYPE_MAX (ERTS_MON_LNK_TYPE_MAX + 5)
+
+#define ERTS_SIG_Q_TYPE_UNDEFINED \
+    (ERTS_MON_LNK_TYPE_MAX + 1)
+#define ERTS_SIG_Q_TYPE_DIST_LINK \
+    (ERTS_MON_LNK_TYPE_MAX + 2)
+#define ERTS_SIG_Q_TYPE_GEN_EXIT \
+    (ERTS_MON_LNK_TYPE_MAX + 3)
+#define ERTS_SIG_Q_TYPE_DIST_PROC_DEMONITOR \
+    (ERTS_MON_LNK_TYPE_MAX + 4)
+#define ERTS_SIG_Q_TYPE_ADJUST_TRACE_INFO \
+    ERTS_SIG_Q_TYPE_MAX
+
+
+#define ERTS_SIG_Q_OP_BITS      8                      
+#define ERTS_SIG_Q_OP_SHIFT     0
+#define ERTS_SIG_Q_OP_MASK      ((1 << ERTS_SIG_Q_OP_BITS) - 1)
+
+#define ERTS_SIG_Q_TYPE_BITS    8
+#define ERTS_SIG_Q_TYPE_SHIFT   ERTS_SIG_Q_OP_BITS
+#define ERTS_SIG_Q_TYPE_MASK    ((1 << ERTS_SIG_Q_TYPE_BITS) - 1)
+
+#define ERTS_SIG_Q_NON_X_BITS__ (_HEADER_ARITY_OFFS \
+                                 + ERTS_SIG_Q_OP_BITS \
+                                 + ERTS_SIG_Q_TYPE_BITS)
+
+#define ERTS_SIG_Q_XTRA_BITS    (32 - ERTS_SIG_Q_NON_X_BITS__)
+#define ERTS_SIG_Q_XTRA_SHIFT   (ERTS_SIG_Q_OP_BITS \
+                                 + ERTS_SIG_Q_TYPE_BITS)
+#define ERTS_SIG_Q_XTRA_MASK    ((1 << ERTS_SIG_Q_XTRA_BITS) - 1)
+
+#define ERTS_PROC_SIG_OP(Tag) \
+    ((int) (_unchecked_thing_arityval((Tag)) \
+            >> ERTS_SIG_Q_OP_SHIFT) & ERTS_SIG_Q_OP_MASK)
+
+#define ERTS_PROC_SIG_TYPE(Tag) \
+    ((Uint16) (_unchecked_thing_arityval((Tag)) \
+               >> ERTS_SIG_Q_TYPE_SHIFT) & ERTS_SIG_Q_TYPE_MASK)
+
+#define ERTS_PROC_SIG_XTRA(Tag) \
+    ((Uint32) (_unchecked_thing_arityval((Tag)) \
+               >> ERTS_SIG_Q_XTRA_SHIFT) & ERTS_SIG_Q_XTRA_MASK)
+
+#define ERTS_PROC_SIG_MAKE_TAG(Op, Type, Xtra)                  \
+    (ASSERT(0 <= (Xtra) && (Xtra) <= ERTS_SIG_Q_XTRA_MASK),     \
+     _make_header((((Type) & ERTS_SIG_Q_TYPE_MASK)              \
+                   << ERTS_SIG_Q_TYPE_SHIFT)                    \
+                  | (((Op) & ERTS_SIG_Q_OP_MASK)                \
+                     << ERTS_SIG_Q_OP_SHIFT)                    \
+                  | (((Xtra) & ERTS_SIG_Q_XTRA_MASK)            \
+                     << ERTS_SIG_Q_XTRA_SHIFT),                 \
+                  _TAG_HEADER_EXTERNAL_PID))
+
+Process *ERTS_WRITE_UNLIKELY(erts_dirty_process_signal_handler);
+Process *ERTS_WRITE_UNLIKELY(erts_dirty_process_signal_handler_high);
+Process *ERTS_WRITE_UNLIKELY(erts_dirty_process_signal_handler_max);
+
+void
+erts_proc_sig_queue_init(void)
+{
+    ERTS_CT_ASSERT(ERTS_SIG_Q_OP_MASK >= ERTS_SIG_Q_OP_MAX);
+    ERTS_CT_ASSERT(ERTS_SIG_Q_TYPE_MASK >= ERTS_SIG_Q_TYPE_MAX);
+}
+
+typedef struct {
+    int active;
+    int procs;
+    struct {
+        int active;
+#if defined(USE_VM_PROBES)
+        int vm_probes;
+        char receiver_name[DTRACE_TERM_BUF_SIZE];
+#endif
+        int receive_trace;
+        int bp_ix;
+        ErtsMessage **next;
+        ErtsTracingEvent *event;
+    } messages;
+} ErtsSigRecvTracing;
+
+typedef struct {
+    Eterm message;
+    Eterm from;
+    Eterm reason;
+    union {
+        Eterm ref;
+        int normal_kills;
+    } u;
+} ErtsExitSignalData;
+
+typedef struct {
+    Eterm message;
+    Eterm key;
+} ErtsPersistMonMsg;
+
+typedef struct {
+    ErtsSignalCommon common;
+    Eterm local; /* internal pid (immediate) */
+    Eterm remote; /* external pid (heap for it follow) */
+    Eterm heap[EXTERNAL_THING_HEAD_SIZE + 1];
+} ErtsSigDistLinkOp;
+
+typedef struct {
+    ErtsSignalCommon common;
+    Uint flags_on;
+    Uint flags_off;
+    Eterm tracer;
+} ErtsSigTraceInfo;
+
+#define ERTS_SIG_GL_FLG_ACTIVE          (((erts_aint_t) 1) << 0)
+#define ERTS_SIG_GL_FLG_RECEIVER        (((erts_aint_t) 1) << 1)
+#define ERTS_SIG_GL_FLG_SENDER          (((erts_aint_t) 1) << 2)
+
+typedef struct {
+    ErtsSignalCommon common;
+    erts_atomic_t flags;
+    Eterm group_leader;
+    Eterm reply_to;
+    Eterm ref;
+    ErlOffHeap oh;
+    Eterm heap[1];
+} ErtsSigGroupLeader;
+
+static int handle_msg_tracing(Process *c_p,
+                              ErtsSigRecvTracing *tracing,
+                              ErtsMessage ***next_nm_sig);
+static int handle_trace_change_state(Process *c_p,
+                                     ErtsSigRecvTracing *tracing,
+                                     Uint16 type,
+                                     ErtsMessage *sig,
+                                     ErtsMessage ***next_nm_sig);
+static void getting_unlinked(Process *c_p, Eterm unlinker);
+static void getting_linked(Process *c_p, Eterm linker);
+static void group_leader_reply(Process *c_p, Eterm to,
+                               Eterm ref, int success);
+static int stretch_limit(Process *c_p, ErtsSigRecvTracing *tp,
+                         int abs_lim, int *limp);
+
+#ifdef ERTS_PROC_SIG_HARD_DEBUG
+#define ERTS_PROC_SIG_HDBG_PRIV_CHKQ(P, T, NMN)                 \
+    do {                                                        \
+        ErtsMessage **nm_next__ = *(NMN);                       \
+        ErtsMessage **nm_last__ = (P)->sig_qs.nmsigs.last;      \
+        if (!nm_next__ || !*nm_next__) {                        \
+            nm_next__ = NULL;                                   \
+            nm_last__ = NULL;                                   \
+        }                                                       \
+        proc_sig_hdbg_check_queue((P),                          \
+                                  1,                            \
+                                  &(P)->sig_qs.cont,            \
+                                  (P)->sig_qs.cont_last,        \
+                                  nm_next__,                    \
+                                  nm_last__,                    \
+                                  (T),                          \
+                                  NULL,                         \
+                                  ERTS_PSFLG_FREE);             \
+    } while (0);
+static Sint
+proc_sig_hdbg_check_queue(Process *c_p,
+                          int privq,
+                          ErtsMessage **sig_next,
+                          ErtsMessage **sig_last,
+                          ErtsMessage **sig_nm_next,
+                          ErtsMessage **sig_nm_last,
+                          ErtsSigRecvTracing *tracing,
+                          int *found_saved_last_p,
+                          erts_aint32_t sig_psflg);
+#else
+#define ERTS_PROC_SIG_HDBG_PRIV_CHKQ(P, T, NMN)
+#endif
+
+typedef struct {
+    ErtsSignalCommon common;
+    Eterm ref;
+    Eterm heap[1];
+} ErtsSigDistProcDemonitor;
+
+static void
+destroy_dist_proc_demonitor(ErtsSigDistProcDemonitor *dmon)
+{
+    Eterm ref = dmon->ref;
+    if (is_external(ref)) {
+        ExternalThing *etp = external_thing_ptr(ref);
+        erts_deref_node_entry(etp->node);
+    }
+    erts_free(ERTS_ALC_T_DIST_DEMONITOR, dmon);
+}
+
+static ERTS_INLINE ErtsSigDistLinkOp *
+make_sig_dist_link_op(int op, Eterm local, Eterm remote)
+{
+    Eterm *hp;
+    ErlOffHeap oh = {0};
+    ErtsSigDistLinkOp *sdlnk = erts_alloc(ERTS_ALC_T_SIG_DATA,
+                                          sizeof(ErtsSigDistLinkOp));
+    ASSERT(is_internal_pid(local));
+    ASSERT(is_external_pid(remote));
+
+    hp = &sdlnk->heap[0];
+
+    sdlnk->common.tag = ERTS_PROC_SIG_MAKE_TAG(op,
+                                               ERTS_SIG_Q_TYPE_DIST_LINK,
+                                               0);
+    sdlnk->local = local;
+    sdlnk->remote = STORE_NC(&hp, &oh, remote);
+
+    ASSERT(&sdlnk->heap[0] < hp);
+    ASSERT(hp <= &sdlnk->heap[0] + sizeof(sdlnk->heap)/sizeof(sdlnk->heap[0]));
+    ASSERT(boxed_val(sdlnk->remote) == &sdlnk->heap[0]);
+
+    return sdlnk;
+}
+
+static ERTS_INLINE void
+destroy_sig_dist_link_op(ErtsSigDistLinkOp *sdlnk)
+{
+    ASSERT(is_external_pid(sdlnk->remote));
+    ASSERT(boxed_val(sdlnk->remote) == &sdlnk->heap[0]);
+    erts_deref_node_entry(((ExternalThing *) &sdlnk->heap[0])->node);
+    erts_free(ERTS_ALC_T_SIG_DATA, sdlnk);
+}
+
+static ERTS_INLINE ErtsExitSignalData *
+get_exit_signal_data(ErtsMessage *xsig)
+{
+    ASSERT(ERTS_SIG_IS_NON_MSG(xsig));
+    ASSERT((ERTS_PROC_SIG_OP(((ErtsSignal *) xsig)->common.tag)
+            == ERTS_SIG_Q_OP_EXIT)
+           || (ERTS_PROC_SIG_OP(((ErtsSignal *) xsig)->common.tag)
+                == ERTS_SIG_Q_OP_EXIT_LINKED)
+           || (ERTS_PROC_SIG_OP(((ErtsSignal *) xsig)->common.tag)
+               == ERTS_SIG_Q_OP_MONITOR_DOWN));
+    ASSERT(xsig->hfrag.alloc_size > xsig->hfrag.used_size);
+    ASSERT((xsig->hfrag.alloc_size - xsig->hfrag.used_size)*sizeof(UWord)
+           >= sizeof(ErtsExitSignalData));
+    return (ErtsExitSignalData *) (char *) (&xsig->hfrag.mem[0]
+                                            + xsig->hfrag.used_size);
+}
+
+static ERTS_INLINE void
+destroy_trace_info(ErtsSigTraceInfo *ti)
+{
+    if (is_value(ti->tracer))
+        erts_tracer_update(&ti->tracer, NIL);
+    erts_free(ERTS_ALC_T_SIG_DATA, ti);
+}
+
+static void
+destroy_sig_group_leader(ErtsSigGroupLeader *sgl)
+{
+    erts_cleanup_offheap(&sgl->oh);
+    erts_free(ERTS_ALC_T_SIG_DATA, sgl);
+}
+
+static ERTS_INLINE void
+sig_enqueue_trace(Process *c_p, ErtsMessage *sig, int op,
+                  Process *rp, ErtsMessage **first,
+                  ErtsMessage **last, ErtsMessage ***last_next)
+{
+    switch (op) {
+    case ERTS_SIG_Q_OP_LINK:
+        if (c_p
+            && ((!!IS_TRACED(c_p))
+                & (ERTS_TRACE_FLAGS(c_p) & (F_TRACE_SOL
+                                            | F_TRACE_SOL1)))) {
+            ErtsSigTraceInfo *ti;
+            Eterm tag;
+            /*
+             * Set on link enabled.
+             *
+             * Prepend a trace-change-state signal before the
+             * link signal...
+             */
+
+            tag = ERTS_PROC_SIG_MAKE_TAG(ERTS_SIG_Q_OP_TRACE_CHANGE_STATE,
+                                         ERTS_SIG_Q_TYPE_ADJUST_TRACE_INFO,
+                                         0);
+            ti = erts_alloc(ERTS_ALC_T_SIG_DATA, sizeof(ErtsSigTraceInfo));
+            ti->common.next = *last;
+            ti->common.specific.next = &ti->common.next;
+            ti->common.tag = tag;
+            ti->flags_on = ERTS_TRACE_FLAGS(c_p) & TRACEE_FLAGS;
+            if (!(ti->flags_on & F_TRACE_SOL1))
+                ti->flags_off = 0;
+            else {
+                ti->flags_off = F_TRACE_SOL1|F_TRACE_SOL;
+                erts_proc_lock(c_p, ERTS_PROC_LOCKS_ALL_MINOR);
+                ERTS_TRACE_FLAGS(c_p) &= ~(F_TRACE_SOL1|F_TRACE_SOL);
+                erts_proc_unlock(c_p, ERTS_PROC_LOCKS_ALL_MINOR);
+            }
+            erts_tracer_update(&ti->tracer, ERTS_TRACER(c_p));
+            *first = (ErtsMessage *) ti;
+            *last_next = &ti->common.next;
+        }
+        break;
+
+#ifdef USE_VM_PROBES
+    case ERTS_SIG_Q_OP_EXIT:
+    case ERTS_SIG_Q_OP_EXIT_LINKED: {
+        ErtsExitSignalData *xsigd = get_exit_signal_data(sig);
+        if(DTRACE_ENABLED(process_exit_signal) && is_pid(xsigd->from)) {
+            DTRACE_CHARBUF(sender_str, DTRACE_TERM_BUF_SIZE);
+            DTRACE_CHARBUF(receiver_str, DTRACE_TERM_BUF_SIZE);
+            DTRACE_CHARBUF(reason_buf, DTRACE_TERM_BUF_SIZE);
+
+            dtrace_pid_str(from, sender_str);
+            dtrace_proc_str(rp, receiver_str);
+            erts_snprintf(reason_buf, sizeof(DTRACE_CHARBUF_NAME(reason_buf)) - 1, "%T", reason);
+            DTRACE3(process_exit_signal, sender_str, receiver_str, reason_buf);
+        }
+        break;
+    }
+#endif
+
+    default:
+        break;
+    }
+}
+
+static void
+sig_enqueue_trace_cleanup(ErtsMessage *first, ErtsSignal *sig, ErtsMessage *last)
+{
+    ErtsMessage *tmp;
+
+    /* The usual case; no tracing signals... */
+    if (sig == (ErtsSignal *) first && sig == (ErtsSignal *) last) {
+        sig->common.next = NULL;
+        return;
+    }
+
+    /* Got trace signals to clean up... */
+
+    tmp = first;
+
+    while (tmp) {
+        ErtsMessage *tmp_free = tmp;
+        tmp = tmp->next;
+        if (sig != (ErtsSignal *) tmp_free) {
+            switch (ERTS_PROC_SIG_OP(((ErtsSignal *) tmp_free)->common.tag)) {
+            case ERTS_SIG_Q_OP_TRACE_CHANGE_STATE:
+                destroy_trace_info((ErtsSigTraceInfo *) tmp_free);
+                break;
+            default:
+                ERTS_INTERNAL_ERROR("Unexpected signal op");
+                break;
+            }
+        }
+    }
+}
+
+static ERTS_INLINE erts_aint32_t
+enqueue_signals(Process *rp, ErtsMessage *first,
+                ErtsMessage *last, ErtsMessage **last_next,
+                erts_aint32_t in_state)
+{
+    erts_aint32_t state = in_state;
+    ErtsMessage **this = rp->sig_inq.last;
+
+    ERTS_HDBG_CHECK_SIGNAL_IN_QUEUE(rp);
+
+    ASSERT(!*this);
+    *this = first;
+    rp->sig_inq.last = &last->next;
+
+    if (!rp->sig_inq.nmsigs.next) {
+        ASSERT(!rp->sig_inq.nmsigs.last);
+        rp->sig_inq.nmsigs.next = this;
+        state = erts_atomic32_read_bor_nob(&rp->state,
+                                           ERTS_PSFLG_SIG_IN_Q);
+        ASSERT(!(state & ERTS_PSFLG_SIG_IN_Q));
+    }
+    else {
+        ErtsSignal *sig;
+        ASSERT(rp->sig_inq.nmsigs.last);
+
+        sig = (ErtsSignal *) *rp->sig_inq.nmsigs.last;
+
+        ASSERT(sig && !sig->common.specific.next);
+        ASSERT(state & ERTS_PSFLG_SIG_IN_Q);
+        sig->common.specific.next = this;
+    }
+
+    if (last_next) {
+        ASSERT(first != last);
+        rp->sig_inq.nmsigs.last = last_next;
+    }
+    else {
+        ASSERT(first == last);
+        rp->sig_inq.nmsigs.last = this;
+    }
+
+    ERTS_HDBG_CHECK_SIGNAL_IN_QUEUE(rp);
+
+    return state;
+}
+
+static ERTS_INLINE void
+ensure_dirty_proc_handled(Eterm pid,
+                          erts_aint32_t state,
+                          erts_aint32_t prio)
+{
+    if (state & (ERTS_PSFLG_DIRTY_RUNNING
+                 | ERTS_PSFLG_DIRTY_RUNNING_SYS)) {
+        Eterm *hp;
+        ErtsMessage *mp;
+        Process *sig_handler;
+
+        if (prio < 0)
+            prio = (int) ERTS_PSFLGS_GET_USR_PRIO(state);
+
+        switch (prio) {
+        case PRIORITY_MAX:
+            sig_handler = erts_dirty_process_signal_handler_max;
+            break;
+        case PRIORITY_HIGH:
+            sig_handler = erts_dirty_process_signal_handler_high;
+            break;
+        default:
+            sig_handler = erts_dirty_process_signal_handler;
+            break;
+        }
+
+        /* Make sure signals are handled... */
+        mp = erts_alloc_message(0, &hp);
+        erts_queue_message(sig_handler, 0, mp, pid, am_system);
+    }
+}
+
+static int
+proc_queue_signal(Process *c_p, Eterm pid, ErtsSignal *sig, int op)
+{
+    int res;
+    Process *rp;
+    ErtsMessage *first, *last, **last_next;
+    ErtsSchedulerData *esdp = erts_get_scheduler_data();
+    int is_normal_sched = !!esdp && esdp->type == ERTS_SCHED_NORMAL;
+    erts_aint32_t state;
+
+    if (is_normal_sched)
+        rp = erts_proc_lookup_raw(pid);
+    else
+        rp = erts_proc_lookup_raw_inc_refc(pid);
+
+    if (!rp)
+        return 0;
+
+    sig->common.specific.next = NULL;
+    first = last = (ErtsMessage *) sig;
+    last_next = NULL;
+
+    /* may add signals before and/or after sig */
+    sig_enqueue_trace(c_p, first, op, rp,
+                      &first, &last, &last_next);
+
+    last->next = NULL;
+
+    erts_proc_lock(rp, ERTS_PROC_LOCK_MSGQ);
+
+    state = erts_atomic32_read_nob(&rp->state);
+
+    if (ERTS_PSFLG_FREE & state)
+        res = 0;
+    else {
+        state = enqueue_signals(rp, first, last, last_next, state);
+        res = !0;
+    }
+
+    erts_proc_unlock(rp, ERTS_PROC_LOCK_MSGQ);
+
+    if (res == 0)
+        sig_enqueue_trace_cleanup(first, sig, last);
+
+    if (!(state & (ERTS_PSFLG_EXITING
+                   | ERTS_PSFLG_ACTIVE_SYS
+                   | ERTS_PSFLG_SIG_IN_Q))) {
+        /* Schedule process... */
+        state = erts_proc_sys_schedule(rp, state, 0);
+    }
+
+    ensure_dirty_proc_handled(rp->common.id, state, -1);
+
+    if (!is_normal_sched)
+        erts_proc_dec_refc(rp);
+
+    return res;
+}
+
+void
+erts_proc_sig_fetch(Process *proc)
+{
+#ifdef ERTS_PROC_SIG_HARD_DEBUG
+    ErtsSignalPrivQueues sig_qs = proc->sig_qs;
+    ErtsSignalInQueue sig_inq = proc->sig_inq;
+#endif
+
+    ERTS_LC_ASSERT(erts_thr_progress_is_blocking()
+                   || ERTS_PROC_IS_EXITING(proc)
+                   || ((erts_proc_lc_my_proc_locks(proc)
+                        & (ERTS_PROC_LOCK_MAIN
+                           | ERTS_PROC_LOCK_MSGQ))
+                       == (ERTS_PROC_LOCK_MAIN
+                           | ERTS_PROC_LOCK_MSGQ)));
+
+    if (!proc->sig_inq.first) {
+        ASSERT(proc->sig_inq.last == &proc->sig_inq.first);
+        ASSERT(proc->sig_inq.len == 0);
+        ASSERT(!proc->sig_inq.nmsigs.next);
+        ASSERT(!proc->sig_inq.nmsigs.last);
+        return;
+    }
+
+    ERTS_HDBG_CHECK_SIGNAL_IN_QUEUE(proc);
+    ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE(proc);
+
+    if (!proc->sig_inq.nmsigs.next) {
+        ASSERT(!(ERTS_PSFLG_SIG_IN_Q
+                 & erts_atomic32_read_nob(&proc->state)));
+        ASSERT(!proc->sig_inq.nmsigs.last);
+
+        if (proc->sig_qs.cont || ERTS_MSG_RECV_TRACED(proc)) {
+            *proc->sig_qs.cont_last = proc->sig_inq.first;
+            proc->sig_qs.cont_last = proc->sig_inq.last;
+        }
+        else {
+            *proc->sig_qs.last = proc->sig_inq.first;
+            proc->sig_qs.last = proc->sig_inq.last;
+        }
+    }
+    else {
+#ifdef DEBUG
+        erts_aint32_t s;
+#endif
+        ASSERT(proc->sig_inq.nmsigs.last);
+         if (!proc->sig_qs.nmsigs.last) {
+            ASSERT(!proc->sig_qs.nmsigs.next);
+            if (proc->sig_inq.nmsigs.next == &proc->sig_inq.first)
+                proc->sig_qs.nmsigs.next = proc->sig_qs.cont_last;
+            else
+                proc->sig_qs.nmsigs.next = proc->sig_inq.nmsigs.next;
+
+#ifdef DEBUG
+            s =
+#endif
+                erts_atomic32_read_bset_nob(&proc->state,
+                                            (ERTS_PSFLG_SIG_Q
+                                             | ERTS_PSFLG_SIG_IN_Q),
+                                            ERTS_PSFLG_SIG_Q);
+
+            ASSERT((s & (ERTS_PSFLG_SIG_Q|ERTS_PSFLG_SIG_IN_Q))
+                   == ERTS_PSFLG_SIG_IN_Q);
+        }
+        else {
+            ErtsSignal *sig;
+            ASSERT(proc->sig_qs.nmsigs.next);
+            sig = ((ErtsSignal *) *proc->sig_qs.nmsigs.last);
+            ASSERT(ERTS_SIG_IS_NON_MSG(sig));
+            ASSERT(!sig->common.specific.next);
+            if (proc->sig_inq.nmsigs.next == &proc->sig_inq.first)
+                sig->common.specific.next = proc->sig_qs.cont_last;
+            else
+                sig->common.specific.next = proc->sig_inq.nmsigs.next;
+
+#ifdef DEBUG
+            s =
+#endif
+                erts_atomic32_read_band_nob(&proc->state,
+                                            ~ERTS_PSFLG_SIG_IN_Q);
+
+            ASSERT((s & (ERTS_PSFLG_SIG_Q|ERTS_PSFLG_SIG_IN_Q))
+                   == (ERTS_PSFLG_SIG_Q|ERTS_PSFLG_SIG_IN_Q));
+        }
+        if (proc->sig_inq.nmsigs.last == &proc->sig_inq.first)
+            proc->sig_qs.nmsigs.last = proc->sig_qs.cont_last;
+        else
+            proc->sig_qs.nmsigs.last = proc->sig_inq.nmsigs.last;
+        proc->sig_inq.nmsigs.next = NULL;
+        proc->sig_inq.nmsigs.last = NULL;
+
+        *proc->sig_qs.cont_last = proc->sig_inq.first;
+        proc->sig_qs.cont_last = proc->sig_inq.last;
+    }
+
+    proc->sig_qs.len += proc->sig_inq.len;
+
+    proc->sig_inq.first = NULL;
+    proc->sig_inq.last = &proc->sig_inq.first;
+    proc->sig_inq.len = 0;
+
+    ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE(proc);
+}
+
+void do_seq_trace_output(Eterm to, Eterm token, Eterm msg);
+
+static void
+send_gen_exit_signal(Process *c_p, Eterm from_tag,
+                     Eterm from, Eterm to,
+                     Sint16 op, Eterm reason, Eterm ref,
+                     Eterm token, int normal_kills)
+{
+    ErtsExitSignalData *xsigd;
+    Eterm *hp, *start_hp, s_reason, s_ref, s_message, s_token, s_from;
+    ErtsMessage *mp;
+    ErlHeapFragment *hfrag;
+    ErlOffHeap *ohp;
+    Uint hsz, from_sz, reason_sz, ref_sz, token_sz;
+    int seq_trace;
+#ifdef USE_VM_PROBES
+    Eterm s_utag, utag;
+    Uint utag_sz;
+#endif
+
+    ASSERT(is_immed(from_tag));
+
+    hsz = sizeof(ErtsExitSignalData)/sizeof(Uint);
+
+    seq_trace = c_p && have_seqtrace(token);
+    if (seq_trace)
+        seq_trace_update_send(c_p);
+
+#ifdef USE_VM_PROBES
+    if (c_p && token != NIL && (DT_UTAG_FLAGS(c_p) & DT_UTAG_SPREADING)) {
+        utag_sz = size_object(DT_UTAG(c_p));
+        utag = DT_UTAG(c_p);
+    }
+    else if (token == am_have_dt_utag) {
+        utag_sz = 0;
+        utag = token = NIL;
+    }
+    hsz += utag_sz;
+#endif
+
+    token_sz = is_immed(token) ? 0 : size_object(token);
+    hsz += token_sz;
+
+    from_sz = is_immed(from) ? 0 : size_object(from);
+    hsz += from_sz;
+
+    reason_sz = is_immed(reason) ? 0 : size_object(reason);
+    hsz += reason_sz;
+
+    switch (op) {
+    case ERTS_SIG_Q_OP_EXIT:
+    case ERTS_SIG_Q_OP_EXIT_LINKED: {
+        /* {'EXIT', From, Reason} */
+        hsz += 4; /* 3-tuple */
+        ref_sz = 0;
+        break;
+    }
+    case ERTS_SIG_Q_OP_MONITOR_DOWN: {
+        /* {'DOWN', Ref, process, From, Reason} */
+        hsz += 6; /* 5-tuple */
+        ref_sz = NC_HEAP_SIZE(ref);
+        hsz += ref_sz;
+        break;
+    }
+    default:
+        ERTS_INTERNAL_ERROR("Invalid exit signal op");
+        break;
+    }
+
+    /*
+     * Allocate message combined with heap fragment...
+     */
+    mp = erts_alloc_message(hsz, &hp);
+    hfrag = &mp->hfrag;
+    mp->next = NULL;
+    ohp = &hfrag->off_heap;
+    start_hp = hp;
+
+    s_token = (is_immed(token)
+                ? token
+                : copy_struct(token, token_sz, &hp, ohp));
+
+    s_reason = (is_immed(reason)
+                ? reason
+                : copy_struct(reason, reason_sz, &hp, ohp));
+
+    s_from = (is_immed(from)
+              ? from
+              : copy_struct(from, from_sz, &hp, ohp));
+
+    if (!ref_sz)
+        s_ref = NIL;
+    else
+        s_ref = STORE_NC(&hp, ohp, ref);
+
+    switch (op) {
+    case ERTS_SIG_Q_OP_EXIT:
+    case ERTS_SIG_Q_OP_EXIT_LINKED:
+        /* {'EXIT', From, Reason} */
+        s_message = TUPLE3(hp, am_EXIT, s_from, s_reason);
+        hp += 4;
+        break;
+    case ERTS_SIG_Q_OP_MONITOR_DOWN:
+        /* {'DOWN', Ref, process, From, Reason} */
+        s_message = TUPLE5(hp, am_DOWN, s_ref, am_process, s_from, s_reason);
+        hp += 6;
+        break;
+    }
+
+#ifdef USE_VM_PROBES
+    s_utag = (is_immed(utag)
+              ? utag
+              : copy_struct(utag, utag_sz, &hp, ohp));
+    ERL_MESSAGE_DT_UTAG(mp) = utag;
+#endif
+
+    ERL_MESSAGE_TERM(mp) = ERTS_PROC_SIG_MAKE_TAG(op,
+                                                  ERTS_SIG_Q_TYPE_GEN_EXIT,
+                                                  0);
+    ERL_MESSAGE_TOKEN(mp) = s_token;
+    ERL_MESSAGE_FROM(mp) = from_tag; /* immediate... */
+
+    hfrag->used_size = hp - start_hp;
+
+    xsigd = (ErtsExitSignalData *) (char *) hp;
+
+    xsigd->message = s_message;
+    xsigd->from = s_from;
+    xsigd->reason = s_reason;
+    if (is_nil(s_ref))
+        xsigd->u.normal_kills = normal_kills;
+    else {
+        ASSERT(is_ref(s_ref));
+        xsigd->u.ref = s_ref;
+    }
+
+    if (seq_trace)
+        do_seq_trace_output(to, s_token, s_message);
+
+    if (!proc_queue_signal(c_p, to, (ErtsSignal *) mp, op)) {
+        mp->next = NULL;
+        erts_cleanup_messages(mp);
+    }
+}
+
+void
+do_seq_trace_output(Eterm to, Eterm token, Eterm msg)
+{
+    /*
+     * We could do this when enqueuing the signal and avoid some
+     * locking. However, the enqueuing code would then always
+     * have the penalty of this seq-tracing code which we do not
+     * want...
+     */
+    ErtsSchedulerData *esdp = erts_get_scheduler_data();
+    int is_normal_sched = !!esdp && esdp->type == ERTS_SCHED_NORMAL;
+    Process *rp;
+
+    if (is_normal_sched)
+        rp = erts_proc_lookup_raw(to);
+    else
+        rp = erts_proc_lookup_raw_inc_refc(to);
+
+    erts_proc_lock(rp, ERTS_PROC_LOCK_MSGQ);
+
+    if (!ERTS_PROC_IS_EXITING(rp))
+        seq_trace_output(token, msg, SEQ_TRACE_SEND, to, rp);
+
+    erts_proc_unlock(rp, ERTS_PROC_LOCK_MSGQ);
+
+    if (!is_normal_sched)
+        erts_proc_dec_refc(rp);
+}
+
+void
+erts_proc_sig_send_persistent_monitor_msg(Uint16 type, Eterm key,
+                                          Eterm from, Eterm to,
+                                          Eterm msg, Uint msg_sz)
+{
+    ErtsPersistMonMsg *prst_mon;
+    ErtsMessage *mp;
+    ErlHeapFragment *hfrag;
+    Eterm *hp, *start_hp, message;
+    ErlOffHeap *ohp;
+    Uint hsz = sizeof(ErtsPersistMonMsg) + msg_sz;
+
+    /*
+     * Allocate message combined with heap fragment...
+     */
+    mp = erts_alloc_message(hsz, &hp);
+    hfrag = &mp->hfrag;
+    mp->next = NULL;
+    ohp = &hfrag->off_heap;
+    start_hp = hp;
+
+    ASSERT(msg_sz == size_object(msg));
+    message = copy_struct(msg, msg_sz, &hp, ohp);
+    hfrag->used_size = hp - start_hp;
+
+    prst_mon = (ErtsPersistMonMsg *) (char *) hp;
+    prst_mon->message = message;
+
+    switch (type) {
+    case ERTS_MON_TYPE_NODES:
+        ASSERT(is_small(key));
+        prst_mon->key = key;
+        break;
+
+    case ERTS_MON_TYPE_TIME_OFFSET:
+        ASSERT(is_internal_ref(key));
+        ASSERT(is_tuple_arity(message, 5));
+
+        prst_mon->key = tuple_val(message)[2];
+
+        ASSERT(eq(prst_mon->key, key));
+        break;
+
+    default:
+        ERTS_INTERNAL_ERROR("Invalid persistent monitor type");
+        prst_mon->key = key;
+        break;
+    }
+
+    ASSERT(is_immed(from));
+
+    ERL_MESSAGE_TERM(mp) = ERTS_PROC_SIG_MAKE_TAG(ERTS_SIG_Q_OP_PERSISTENT_MON_MSG,
+                                                  type, 0);
+    ERL_MESSAGE_FROM(mp) = from;
+    ERL_MESSAGE_TOKEN(mp) = NIL;
+#ifdef USE_VM_PROBES
+    ERL_MESSAGE_DT_UTAG(mp) = NIL;
+#endif
+
+    if (!proc_queue_signal(NULL, to, (ErtsSignal *) mp,
+                           ERTS_SIG_Q_OP_PERSISTENT_MON_MSG)) {
+        mp->next = NULL;
+        erts_cleanup_messages(mp);
+    }
+}
+
+static ERTS_INLINE Eterm
+get_persist_mon_msg(ErtsMessage *sig, Eterm *msg)
+{
+    ErtsPersistMonMsg *prst_mon;
+    prst_mon = ((ErtsPersistMonMsg *)
+                (char *) (&sig->hfrag.mem[0]
+                          + sig->hfrag.used_size));
+    *msg = prst_mon->message;
+    return prst_mon->key;
+}
+
+void
+erts_proc_sig_send_exit(Process *c_p, Eterm from, Eterm to,
+                        Eterm reason, Eterm token,
+                        int normal_kills)
+{
+    Eterm from_tag;
+    ASSERT(!c_p || c_p->common.id == from);
+    if (is_immed(from)) {
+        ASSERT(is_internal_pid(from) || is_internal_port(from));
+        from_tag = from;
+    }
+    else {
+        DistEntry *dep;
+        ASSERT(is_external_pid(from));
+        dep = external_pid_dist_entry(from);
+        from_tag = dep->sysname;
+    }
+    send_gen_exit_signal(c_p, from_tag, from, to, ERTS_SIG_Q_OP_EXIT,
+                         reason, NIL, token, normal_kills);
+}
+
+void
+erts_proc_sig_send_link_exit(Process *c_p, Eterm from, ErtsLink *lnk,
+                             Eterm reason, Eterm token)
+{
+    Eterm to;
+    ASSERT(!c_p || c_p->common.id == from);
+    ASSERT(lnk);
+    to = lnk->other.item;
+    if (is_not_immed(reason) || is_not_nil(token)) {
+        ASSERT(is_internal_pid(from) || is_internal_port(from));
+        send_gen_exit_signal(c_p, from, from, to, ERTS_SIG_Q_OP_EXIT_LINKED,
+                             reason, NIL, token, 0);
+    }
+    else {
+        /* Pass signal using old link structure... */
+        ErtsSignal *sig = (ErtsSignal *) lnk;
+        lnk->other.item = reason; /* pass reason via this other.item */
+        sig->common.tag = ERTS_PROC_SIG_MAKE_TAG(ERTS_SIG_Q_OP_EXIT_LINKED,
+                                                 lnk->type, 0);
+        if (proc_queue_signal(c_p, to, sig, ERTS_SIG_Q_OP_EXIT_LINKED))
+            return; /* receiver will destroy lnk structure */
+    }
+    if (lnk)
+        erts_link_release(lnk);
+}
+
+int
+erts_proc_sig_send_link(Process *c_p, Eterm to, ErtsLink *lnk)
+{
+    ErtsSignal *sig;
+    Uint16 type = lnk->type;
+
+    ASSERT(!c_p || c_p->common.id == lnk->other.item);
+    ASSERT(lnk);
+    ASSERT(is_internal_pid(to));
+
+    sig = (ErtsSignal *) lnk;
+    sig->common.tag = ERTS_PROC_SIG_MAKE_TAG(ERTS_SIG_Q_OP_LINK,
+                                             type, 0);
+
+    return proc_queue_signal(c_p, to, sig, ERTS_SIG_Q_OP_LINK);
+}
+
+void
+erts_proc_sig_send_unlink(Process *c_p, ErtsLink *lnk)
+{
+    ErtsSignal *sig;
+    Eterm to;
+
+    ASSERT(lnk);
+
+    sig = (ErtsSignal *) lnk;
+    to = lnk->other.item;
+
+    ASSERT(is_internal_pid(to));
+
+    sig->common.tag = ERTS_PROC_SIG_MAKE_TAG(ERTS_SIG_Q_OP_UNLINK,
+                                             lnk->type, 0);
+
+    if (!proc_queue_signal(c_p, to, sig, ERTS_SIG_Q_OP_UNLINK))
+        erts_link_release(lnk);
+}
+
+void
+erts_proc_sig_send_dist_link_exit(DistEntry *dep,
+                                  Eterm from, Eterm to,
+                                  Eterm reason, Eterm token)
+{
+    send_gen_exit_signal(NULL, dep->sysname, from, to, ERTS_SIG_Q_OP_EXIT_LINKED,
+                         reason, NIL, token, 0);
+}
+
+void
+erts_proc_sig_send_dist_unlink(DistEntry *dep, Eterm from, Eterm to)
+{
+    ErtsSignal *sig;
+
+    ASSERT(is_internal_pid(to));
+    ASSERT(is_external_pid(from));
+    ASSERT(dep == external_pid_dist_entry(from));
+
+    sig = (ErtsSignal *) make_sig_dist_link_op(ERTS_SIG_Q_OP_UNLINK,
+                                               to, from);
+
+    if (!proc_queue_signal(NULL, to, sig, ERTS_SIG_Q_OP_UNLINK))
+        destroy_sig_dist_link_op((ErtsSigDistLinkOp *) sig);
+}
+
+void
+erts_proc_sig_send_dist_monitor_down(DistEntry *dep, Eterm ref,
+                                     Eterm from, Eterm to,
+                                     Eterm reason)
+{
+    Eterm monitored, heap[3];
+    if (is_atom(from)) 
+        monitored = TUPLE2(&heap[0], from, dep->sysname);
+    else
+        monitored = from;
+    send_gen_exit_signal(NULL, dep->sysname, monitored,
+                         to, ERTS_SIG_Q_OP_MONITOR_DOWN,
+                         reason, ref, NIL, 0);    
+}
+
+void
+erts_proc_sig_send_monitor_down(ErtsMonitor *mon, Eterm reason)
+{
+    Eterm to;
+
+    ASSERT(erts_monitor_is_target(mon));
+    ASSERT(!erts_monitor_is_in_table(mon));
+
+    to = mon->other.item;
+    ASSERT(is_internal_pid(to));
+
+    if (is_immed(reason)) {
+        /* Pass signal using old monitor structure... */
+        ErtsSignal *sig;
+
+        mon->other.item = reason; /* Pass immed reason via other.item... */
+        sig = (ErtsSignal *) mon;
+        sig->common.tag = ERTS_PROC_SIG_MAKE_TAG(ERTS_SIG_Q_OP_MONITOR_DOWN,
+                                                 mon->type, 0);
+        if (proc_queue_signal(NULL, to, sig, ERTS_SIG_Q_OP_MONITOR_DOWN))
+            return; /* receiver will destroy mon structure */
+    }
+    else {
+        ErtsMonitorData *mdp = erts_monitor_to_data(mon);
+        Eterm from_tag, monitored, heap[3];
+
+        if (!(mon->flags & ERTS_ML_FLG_NAME)) {
+            from_tag = monitored = mdp->origin.other.item;
+            if (is_external_pid(from_tag)) {
+                DistEntry *dep = external_pid_dist_entry(from_tag);
+                from_tag = dep->sysname;
+            }
+        }
+        else {
+            ErtsMonitorDataExtended *mdep;
+            Eterm name, node;
+            mdep = (ErtsMonitorDataExtended *) mdp;
+            name = mdep->u.name;
+            ASSERT(is_atom(name));
+            if (mdep->dist) {
+                node = mdep->dist->nodename;
+                from_tag = node;
+            }
+            else {
+                node = erts_this_dist_entry->sysname;
+                from_tag = mdp->origin.other.item;
+            }
+            ASSERT(is_internal_port(from_tag)
+                   || is_internal_pid(from_tag)
+                   || is_atom(from_tag));
+            monitored = TUPLE2(&heap[0], name, node);
+        }    
+        send_gen_exit_signal(NULL, from_tag, monitored,
+                             to, ERTS_SIG_Q_OP_MONITOR_DOWN,
+                             reason, mdp->ref, NIL, 0);
+    }
+    erts_monitor_release(mon);
+}
+
+void
+erts_proc_sig_send_dist_demonitor(Eterm to, Eterm ref)
+{
+    ErtsSigDistProcDemonitor *dmon;
+    ErtsSignal *sig;
+    Eterm *hp;
+    ErlOffHeap oh;
+    size_t size;
+
+    ERTS_INIT_OFF_HEAP(&oh);
+
+    ASSERT(is_internal_pid(to));
+
+    size = sizeof(ErtsSigDistProcDemonitor) - sizeof(Eterm);
+    ASSERT(is_ref(ref));
+    size += NC_HEAP_SIZE(ref)*sizeof(Eterm);
+
+    dmon = erts_alloc(ERTS_ALC_T_DIST_DEMONITOR, size);
+
+    hp = &dmon->heap[0];
+    dmon->ref = STORE_NC(&hp, &oh, ref);
+    sig = (ErtsSignal *) dmon;
+
+    sig->common.tag = ERTS_PROC_SIG_MAKE_TAG(ERTS_SIG_Q_OP_DEMONITOR,
+                                             ERTS_SIG_Q_TYPE_DIST_PROC_DEMONITOR,
+                                             0);
+
+    if (!proc_queue_signal(NULL, to, sig, ERTS_SIG_Q_OP_DEMONITOR))
+        destroy_dist_proc_demonitor(dmon);
+}
+
+void
+erts_proc_sig_send_demonitor(ErtsMonitor *mon)
+{
+    ErtsSignal *sig = (ErtsSignal *) mon;
+    Uint16 type = mon->type;
+    Eterm to = mon->other.item;
+
+    ASSERT(is_internal_pid(to));
+    ASSERT(erts_monitor_is_origin(mon));
+    ASSERT(!erts_monitor_is_in_table(mon));
+
+    sig->common.tag = ERTS_PROC_SIG_MAKE_TAG(ERTS_SIG_Q_OP_DEMONITOR,
+                                             type, 0);
+    
+    if (!proc_queue_signal(NULL, to, sig, ERTS_SIG_Q_OP_DEMONITOR))
+        erts_monitor_release(mon);
+}
+
+int
+erts_proc_sig_send_monitor(ErtsMonitor *mon, Eterm to)
+{
+    ErtsSignal *sig = (ErtsSignal *) mon;
+    Uint16 type = mon->type;
+
+    ASSERT(is_internal_pid(to) || to == am_undefined);
+    ASSERT(erts_monitor_is_target(mon));
+
+    sig->common.tag = ERTS_PROC_SIG_MAKE_TAG(ERTS_SIG_Q_OP_MONITOR,
+                                             type, 0);
+    
+    return proc_queue_signal(NULL, to, sig, ERTS_SIG_Q_OP_MONITOR);
+}
+
+void
+erts_proc_sig_send_trace_change(Eterm to, Uint on, Uint off, Eterm tracer)
+{
+    ErtsSigTraceInfo *ti;
+    Eterm tag;
+
+    ti = erts_alloc(ERTS_ALC_T_SIG_DATA, sizeof(ErtsSigTraceInfo));
+    tag = ERTS_PROC_SIG_MAKE_TAG(ERTS_SIG_Q_OP_TRACE_CHANGE_STATE,
+                                 ERTS_SIG_Q_TYPE_ADJUST_TRACE_INFO,
+                                 0);
+
+    ti->common.tag = tag;
+    ti->flags_off = off;
+    ti->flags_on = on;
+    ti->tracer = NIL;
+    if (is_not_nil(tracer))
+        erts_tracer_update(&ti->tracer, tracer);
+
+    if (!proc_queue_signal(NULL, to, (ErtsSignal *) ti,
+                           ERTS_SIG_Q_OP_TRACE_CHANGE_STATE))
+        destroy_trace_info(ti);
+}
+
+void
+erts_proc_sig_send_group_leader(Process *c_p, Eterm to, Eterm gl, Eterm ref)
+{
+    int res;
+    ErtsSigGroupLeader *sgl;
+    Eterm *hp;
+    Uint gl_sz, ref_sz, size;
+    erts_aint_t init_flags = ERTS_SIG_GL_FLG_ACTIVE|ERTS_SIG_GL_FLG_RECEIVER;
+    if (c_p)
+        init_flags |= ERTS_SIG_GL_FLG_SENDER;
+
+    ASSERT(c_p ? is_internal_ref(ref) : ref == NIL);
+
+    gl_sz = is_immed(gl) ? 0 : size_object(gl);
+    ref_sz = is_immed(ref) ? 0 : size_object(ref);
+    
+    size = sizeof(ErtsSigGroupLeader);
+
+    size += (gl_sz + ref_sz - 1) * sizeof(Eterm);
+
+    sgl = erts_alloc(ERTS_ALC_T_SIG_DATA, size);
+
+    erts_atomic_init_nob(&sgl->flags, init_flags);
+
+    ERTS_INIT_OFF_HEAP(&sgl->oh);
+
+    hp = &sgl->heap[0];
+
+    sgl->group_leader = is_immed(gl) ? gl : copy_struct(gl, gl_sz, &hp, &sgl->oh);
+    sgl->reply_to = c_p ? c_p->common.id : NIL;
+    sgl->ref = is_immed(ref) ? ref : copy_struct(ref, ref_sz, &hp, &sgl->oh);
+
+    sgl->common.tag = ERTS_PROC_SIG_MAKE_TAG(ERTS_SIG_Q_OP_GROUP_LEADER,
+                                             ERTS_SIG_Q_TYPE_UNDEFINED,
+                                             0);
+
+    res = proc_queue_signal(c_p, to, (ErtsSignal *) sgl,
+                            ERTS_SIG_Q_OP_GROUP_LEADER);
+
+    if (!res)
+        destroy_sig_group_leader(sgl);
+    else if (c_p) {
+        int prio_res = !0;
+        erts_aint_t flags, rm_flags = ERTS_SIG_GL_FLG_SENDER;
+        Process *rp;
+        erts_aint32_t state, my_prio, other_prio;
+
+        state = erts_atomic32_read_nob(&c_p->state);
+        my_prio = ERTS_PSFLGS_GET_USR_PRIO(state);
+
+        rp = erts_proc_lookup_raw(to);
+        if (!rp)
+            prio_res = 0;
+        else {
+            state = erts_atomic32_read_nob(&rp->state);
+            other_prio = ERTS_PSFLGS_GET_USR_PRIO(state);
+
+            if (other_prio > my_prio) {
+                /* Others prio is lower than mine; elevate it... */
+                prio_res = erts_sig_prio(to, my_prio);
+                if (prio_res) {
+                    state = erts_atomic32_read_nob(&rp->state);
+                    ensure_dirty_proc_handled(to, state, my_prio);
+                }
+            }
+        }
+        if (!prio_res)
+            rm_flags |= ERTS_SIG_GL_FLG_ACTIVE;
+
+        flags = erts_atomic_read_band_nob(&sgl->flags, ~rm_flags);
+        if (!prio_res && (flags & ERTS_SIG_GL_FLG_ACTIVE))
+            res = 0; /* We deactivated signal... */
+        if ((flags & ~rm_flags) == 0)
+            destroy_sig_group_leader(sgl);
+    }
+
+    if (!res && c_p)
+        group_leader_reply(c_p, c_p->common.id, ref, 0);
+}
+
+static ERTS_INLINE void
+adjust_tracing_state(Process *c_p, ErtsSigRecvTracing *tracing, int setup)
+{
+    if (!IS_TRACED(c_p) || (ERTS_TRACE_FLAGS(c_p) & F_SENSITIVE)) {
+        tracing->messages.active = 0;
+        tracing->messages.receive_trace = 0;
+        tracing->messages.event = NULL;
+        tracing->messages.next = NULL;
+        tracing->procs = 0;
+        tracing->active = 0;
+    }
+    else {
+        Uint flgs = ERTS_TRACE_FLAGS(c_p);
+        int procs_trace = !!(flgs & F_TRACE_PROCS);
+        int recv_trace = !!(flgs & F_TRACE_RECEIVE);
+        /* procs tracing enabled? */
+
+        tracing->procs = procs_trace;
+
+        /* message receive tracing enabled? */
+        tracing->messages.receive_trace = recv_trace;
+        if (!recv_trace)
+            tracing->messages.event = NULL;
+        else {
+            if (tracing->messages.bp_ix < 0)
+                tracing->messages.bp_ix = erts_active_bp_ix();
+            tracing->messages.event = &erts_receive_tracing[tracing->messages.bp_ix];
+        }
+        if (setup) {
+            if (recv_trace)
+                tracing->messages.next = &c_p->sig_qs.cont;
+            else
+                tracing->messages.next = NULL;
+        }
+        tracing->messages.active = recv_trace;
+        tracing->active = recv_trace | procs_trace;
+    }
+
+#if defined(USE_VM_PROBES)
+    /* vm probe message_queued enabled? */
+
+    tracing->messages.vm_probes = DTRACE_ENABLED(message_queued);
+    if (tracing->messages.vm_probes) {
+        dtrace_proc_str(c_p, tracing->messages.receiver_name);
+        tracing->messages.active = !0;
+        tracing->active = !0;
+        if (setup && !tracing->messages.next)
+            tracing->messages.next = &c_p->sig_qs.cont;
+    }
+
+#endif
+}
+
+static ERTS_INLINE void
+setup_tracing_state(Process *c_p, ErtsSigRecvTracing *tracing)
+{
+    tracing->messages.bp_ix = -1;
+    adjust_tracing_state(c_p, tracing, !0);
+}
+
+static ERTS_INLINE void
+remove_iq_sig(Process *c_p, ErtsMessage *sig, ErtsMessage **next_sig)
+{
+    /*
+     * Remove signal from inner queue.
+     */
+    ASSERT(c_p->sig_qs.cont_last != &sig->next);
+    ASSERT(c_p->sig_qs.nmsigs.next != &sig->next);
+    ASSERT(c_p->sig_qs.nmsigs.last != &sig->next);
+
+    if (c_p->sig_qs.save == &sig->next)
+        c_p->sig_qs.save = next_sig;
+    if (c_p->sig_qs.last == &sig->next)
+        c_p->sig_qs.last = next_sig;
+    if (c_p->sig_qs.saved_last == &sig->next)
+        c_p->sig_qs.saved_last = next_sig;
+
+    *next_sig = sig->next;
+}
+
+static ERTS_INLINE void
+remove_mq_sig(Process *c_p, ErtsMessage *sig,
+           ErtsMessage **next_sig, ErtsMessage ***next_nm_sig)
+{
+    /*
+     * Remove signal from middle queue.
+     */
+    ASSERT(c_p->sig_qs.save != &sig->next);
+    ASSERT(c_p->sig_qs.last != &sig->next);
+
+    if (c_p->sig_qs.cont_last == &sig->next)
+	c_p->sig_qs.cont_last = next_sig;
+    if (c_p->sig_qs.saved_last == &sig->next)
+        c_p->sig_qs.saved_last = next_sig;
+    if (*next_nm_sig == &sig->next)
+        *next_nm_sig = next_sig;
+    if (c_p->sig_qs.nmsigs.last == &sig->next)
+        c_p->sig_qs.nmsigs.last = next_sig;
+
+    *next_sig = sig->next;
+}
+
+static ERTS_INLINE void
+remove_nm_sig(Process *c_p, ErtsMessage *sig, ErtsMessage ***next_nm_sig)
+{
+    ErtsMessage **next_sig = *next_nm_sig;
+    ASSERT(ERTS_SIG_IS_NON_MSG(sig));
+    ASSERT(*next_sig == sig);
+    *next_nm_sig = ((ErtsSignal *) sig)->common.specific.next;
+    remove_mq_sig(c_p, sig, next_sig, next_nm_sig);
+}
+
+static ERTS_INLINE void
+convert_to_msg(Process *c_p, ErtsMessage *sig, ErtsMessage *msg,
+               ErtsMessage ***next_nm_sig)
+{
+    ErtsMessage **next_sig = *next_nm_sig;
+    ASSERT(ERTS_SIG_IS_NON_MSG(sig));
+    *next_nm_sig = ((ErtsSignal *) sig)->common.specific.next;
+    c_p->sig_qs.len++;
+    *next_sig = msg;
+    remove_mq_sig(c_p, sig, &msg->next, next_nm_sig);
+}
+
+static ERTS_INLINE void
+convert_to_msgs(Process *c_p, ErtsMessage *sig, Uint no_msgs,
+                ErtsMessage *first_msg, ErtsMessage *last_msg,
+                ErtsMessage ***next_nm_sig)
+{
+    ErtsMessage **next_sig = *next_nm_sig;
+    ASSERT(ERTS_SIG_IS_NON_MSG(sig));
+    *next_nm_sig = ((ErtsSignal *) sig)->common.specific.next;
+    c_p->sig_qs.len += no_msgs;
+    *next_sig = first_msg;
+    remove_mq_sig(c_p, sig, &last_msg->next, next_nm_sig);
+}
+
+static ERTS_INLINE void
+insert_messages(Process *c_p, ErtsMessage **next, ErtsMessage *first,
+                ErtsMessage *last, Uint no_msgs, ErtsMessage ***next_nm_sig)
+{
+    last->next = *next;
+    if (c_p->sig_qs.cont_last == next)
+	c_p->sig_qs.cont_last = &last->next;
+    if (*next_nm_sig == next)
+        *next_nm_sig = &last->next;
+    if (c_p->sig_qs.nmsigs.last == next)
+        c_p->sig_qs.nmsigs.last = &last->next;
+    c_p->sig_qs.len += no_msgs;
+    *next = first;
+}
+
+static ERTS_INLINE void
+remove_mq_m_sig(Process *c_p, ErtsMessage *sig, ErtsMessage **next_sig, ErtsMessage ***next_nm_sig)
+{
+    /* Removing message... */
+    ASSERT(!ERTS_SIG_IS_NON_MSG(sig));
+    ASSERT(c_p->sig_qs.len > 0);
+    c_p->sig_qs.len--;
+    remove_mq_sig(c_p, sig, next_sig, next_nm_sig);
+}
+
+static ERTS_INLINE void
+remove_iq_m_sig(Process *c_p, ErtsMessage *sig, ErtsMessage **next_sig)
+{
+    /* Removing message... */
+    ASSERT(!ERTS_SIG_IS_NON_MSG(sig));
+    ASSERT(c_p->sig_qs.len > 0);
+    c_p->sig_qs.len--;
+    remove_iq_sig(c_p, sig, next_sig);
+}
+
+static ERTS_INLINE void
+convert_prepared_sig_to_msg(Process *c_p, ErtsMessage *sig, Eterm msg,
+                            ErtsMessage ***next_nm_sig)
+{
+    /*
+     * Everything is already there except for the reference to
+     * the message and the combined hfrag marker that needs to be
+     * restored...
+     */
+    *next_nm_sig = ((ErtsSignal *) sig)->common.specific.next;
+    sig->data.attached = ERTS_MSG_COMBINED_HFRAG;
+    ERL_MESSAGE_TERM(sig) = msg;
+    c_p->sig_qs.len++;
+}
+
+static ERTS_INLINE int
+handle_exit_signal(Process *c_p, ErtsSigRecvTracing *tracing,
+                   ErtsMessage *sig, ErtsMessage ***next_nm_sig,
+                   int *exited)
+{
+    ErtsMessage *conv_msg = NULL;
+    ErtsExitSignalData *xsigd = NULL;
+    ErtsLinkData *ldp;
+    ErtsLink *dlnk;
+    Eterm tag = ((ErtsSignal *) sig)->common.tag;
+    Uint16 type = ERTS_PROC_SIG_TYPE(tag);
+    int op = ERTS_PROC_SIG_OP(tag);
+    int destroy = 0;
+    int ignore = 0;
+    int save = 0;
+    int exit = 0;
+    int cnt = 1;
+    Eterm reason;
+    Eterm from;
+
+    if (type == ERTS_SIG_Q_TYPE_GEN_EXIT) {
+        xsigd = get_exit_signal_data(sig);
+        from = xsigd->from;
+        reason = xsigd->reason;
+        if (op != ERTS_SIG_Q_OP_EXIT_LINKED)
+            ignore = 0;
+        else {
+            ErtsLink *llnk = erts_link_tree_lookup(ERTS_P_LINKS(c_p), from);
+            if (!llnk) {
+                /* Link no longer active; ignore... */
+                ignore = !0;
+                destroy = !0;
+                ldp = NULL; /* Avoid erroneous warning... */
+                dlnk = NULL; /* Avoid erroneous warning... */
+            }
+            else {
+                ignore = 0;
+                erts_link_tree_delete(&ERTS_P_LINKS(c_p), llnk);
+                if (llnk->type != ERTS_LNK_TYPE_DIST_PROC)
+                    erts_link_release(llnk);
+                else {
+                    dlnk = erts_link_to_other(llnk, &ldp);
+                    if (erts_link_dist_delete(dlnk))
+                        erts_link_release_both(ldp);
+                    else
+                        erts_link_release(llnk);
+                }
+            }
+        }
+
+        if (!ignore) {
+
+            if ((op != ERTS_SIG_Q_OP_EXIT || reason != am_kill)
+                && (c_p->flags & F_TRAP_EXIT)) {
+                convert_prepared_sig_to_msg(c_p, sig,
+                                            xsigd->message, next_nm_sig);
+                conv_msg = sig;
+            }
+            else if (reason == am_normal && !xsigd->u.normal_kills) {
+                /* Ignore it... */
+                destroy = !0;
+                ignore = !0;
+            }
+            else {
+                /* Terminate... */
+                save = !0;
+                exit = !0;
+                if (op == ERTS_SIG_Q_OP_EXIT && reason == am_kill)
+                    reason = am_killed;
+            }
+        }
+    }
+    else { /* Link exit */
+        ErtsLink *slnk = (ErtsLink *) sig;
+        ErtsLink *llnk = erts_link_to_other(slnk, &ldp);
+
+        ASSERT(type == ERTS_LNK_TYPE_PROC
+               || type == ERTS_LNK_TYPE_PORT
+               || type == ERTS_LNK_TYPE_DIST_PROC);
+
+        from = llnk->other.item;
+        reason = slnk->other.item; /* reason in other.item ... */
+        ASSERT(is_pid(from) || is_internal_port(from));
+        ASSERT(is_immed(reason));
+        ASSERT(op == ERTS_SIG_Q_OP_EXIT_LINKED);
+        dlnk = erts_link_tree_key_delete(&ERTS_P_LINKS(c_p), llnk);
+        if (!dlnk) {
+            ignore = !0; /* Link no longer active; ignore... */
+            ldp = NULL;
+        }
+        else {
+            Eterm pid;
+            ErtsMessage *mp;
+            ErtsProcLocks locks;
+            Uint hsz;
+            Eterm *hp;
+            ErlOffHeap *ohp;
+            ignore = 0;
+            if (dlnk == llnk)
+                dlnk = NULL;
+            else
+                ldp = NULL;
+
+            ASSERT(is_immed(reason));
+
+            if (!(c_p->flags & F_TRAP_EXIT)) {
+                if (reason == am_normal)
+                    ignore = !0; /* Ignore it... */
+                else
+                    exit = !0; /* Terminate... */
+            }
+            else {
+
+                /*
+                 * Create and EXIT message and replace
+                 * the original signal with the message...
+                 */
+
+                locks = ERTS_PROC_LOCK_MAIN;
+
+                hsz = 4 + NC_HEAP_SIZE(from);
+
+                mp = erts_alloc_message_heap(c_p, &locks, hsz, &hp, &ohp);
+
+                if (locks != ERTS_PROC_LOCK_MAIN)
+                    erts_proc_unlock(c_p, locks & ~ERTS_PROC_LOCK_MAIN);
+
+                pid = STORE_NC(&hp, ohp, from);
+
+                ERL_MESSAGE_TERM(mp) = TUPLE3(hp, am_EXIT, pid, reason);
+                ERL_MESSAGE_TOKEN(mp) = NIL;
+#ifdef USE_VM_PROBES
+                ERL_MESSAGE_DT_UTAG(mp) = NIL;
+#endif
+                if (is_immed(pid))
+                    ERL_MESSAGE_FROM(mp) = pid;
+                else {
+                    DistEntry *dep;
+                    ASSERT(is_external_pid(pid));
+                    dep = external_pid_dist_entry(pid);
+                    ERL_MESSAGE_FROM(mp) = dep->sysname;
+                }
+
+                /* Replace original signal with the exit message... */
+                convert_to_msg(c_p, sig, mp, next_nm_sig);
+
+                cnt += 4;
+
+                conv_msg = mp;
+            }
+        }
+        destroy = !0;
+    }
+
+    if (ignore|exit) {
+        remove_nm_sig(c_p, sig, next_nm_sig);
+        if (exit) {
+            if (save) {
+                sig->data.attached = ERTS_MSG_COMBINED_HFRAG;
+                ERL_MESSAGE_TERM(sig) = xsigd->message;
+                erts_save_message_in_proc(c_p, sig);
+            }
+            /* Exit process... */
+            erts_set_self_exiting(c_p, reason);
+
+            cnt++;
+        }
+    }
+
+    if (!exit) {
+        if (conv_msg)
+            erts_proc_notify_new_message(c_p, ERTS_PROC_LOCK_MAIN);
+        if (op == ERTS_SIG_Q_OP_EXIT_LINKED && tracing->procs)
+            getting_unlinked(c_p, from);
+    }
+
+    if (destroy) {
+        cnt++;
+        if (type == ERTS_SIG_Q_TYPE_GEN_EXIT) {
+            sig->next = NULL;
+            erts_cleanup_messages(sig);
+        }
+        else {
+            if (ldp)
+                erts_link_release_both(ldp);
+            else {
+                if (dlnk)
+                    erts_link_release(dlnk);
+                erts_link_release((ErtsLink *) sig);
+            }
+        }
+    }
+
+    *exited = exit;
+
+    return cnt;
+}
+
+static ERTS_INLINE int
+convert_prepared_down_message(Process *c_p, ErtsMessage *sig,
+                              Eterm msg, ErtsMessage ***next_nm_sig)
+{
+    convert_prepared_sig_to_msg(c_p, sig, msg, next_nm_sig);
+    erts_proc_notify_new_message(c_p, ERTS_PROC_LOCK_MAIN);
+    return 1;
+}
+
+static int
+convert_to_down_message(Process *c_p,
+                        ErtsMessage *sig,
+                        ErtsMonitorData *mdp,
+                        Uint16 mon_type,
+                        ErtsMessage ***next_nm_sig)
+{
+    /*
+     * Create a 'DOWN' message and replace the signal
+     * with it...
+     */
+    int cnt = 0;
+    Eterm node = am_undefined;
+    ErtsMessage *mp;
+    ErtsProcLocks locks;
+    Uint hsz;
+    Eterm *hp, ref, from, type, reason;
+    ErlOffHeap *ohp;
+
+    ASSERT(mdp);
+    ASSERT((mdp->origin.flags & ERTS_ML_FLGS_SAME)
+           == (mdp->target.flags & ERTS_ML_FLGS_SAME));
+
+    hsz = 6; /* 5-tuple */
+
+    if (mdp->origin.flags & ERTS_ML_FLG_NAME)
+        hsz += 3;  /* reg name 2-tuple */
+    else {
+        ASSERT(is_pid(mdp->origin.other.item)
+               || is_internal_port(mdp->origin.other.item));
+        hsz += NC_HEAP_SIZE(mdp->origin.other.item);
+    }
+
+    ASSERT(is_ref(mdp->ref));
+    hsz += NC_HEAP_SIZE(mdp->ref);
+
+    locks = ERTS_PROC_LOCK_MAIN;
+
+    /* reason is mdp->target.other.item */
+    reason = mdp->target.other.item;
+    ASSERT(is_immed(reason));
+
+    mp = erts_alloc_message_heap(c_p, &locks, hsz, &hp, &ohp);
+
+    if (locks != ERTS_PROC_LOCK_MAIN)
+        erts_proc_unlock(c_p, locks & ~ERTS_PROC_LOCK_MAIN);
+
+    cnt += 4;
+
+    ref = STORE_NC(&hp, ohp, mdp->ref);
+
+    if (!(mdp->origin.flags & ERTS_ML_FLG_NAME)) {
+        from = STORE_NC(&hp, ohp, mdp->origin.other.item);
+    }
+    else {
+        ErtsMonitorDataExtended *mdep;
+        ASSERT(mdp->origin.flags & ERTS_ML_FLG_EXTENDED);
+        mdep = (ErtsMonitorDataExtended *) mdp;
+        ASSERT(is_atom(mdep->u.name));
+        if (mdep->dist)
+            node = mdep->dist->nodename;
+        else
+            node = erts_this_dist_entry->sysname;
+        from = TUPLE2(hp, mdep->u.name, node);
+        hp += 3;
+    }
+
+    ASSERT(mdp->origin.type == mon_type);
+    switch (mon_type) {
+    case ERTS_MON_TYPE_PORT:
+        type = am_port;
+        if (mdp->origin.other.item == am_undefined) {
+            /* failed by name... */
+            ERL_MESSAGE_FROM(mp) = am_system;
+        }
+        else {
+            ASSERT(is_internal_port(mdp->origin.other.item));
+            ERL_MESSAGE_FROM(mp) = mdp->origin.other.item;
+        }
+        break;
+    case ERTS_MON_TYPE_PROC:
+        type = am_process;
+        if (mdp->origin.other.item == am_undefined) {
+            /* failed by name... */
+            ERL_MESSAGE_FROM(mp) = am_system;
+        }
+        else {
+            ASSERT(is_internal_pid(mdp->origin.other.item));
+            ERL_MESSAGE_FROM(mp) = mdp->origin.other.item;
+        }
+        break;
+    case ERTS_MON_TYPE_DIST_PROC:
+        type = am_process;
+        if (node == am_undefined) {
+            ErtsMonitorDataExtended *mdep;
+            ASSERT(mdp->origin.flags & ERTS_ML_FLG_EXTENDED);
+            mdep = (ErtsMonitorDataExtended *) mdp;
+            ASSERT(mdep->dist);
+            node = mdep->dist->nodename;
+        }
+        ASSERT(is_atom(node) && node != am_undefined);
+        ERL_MESSAGE_FROM(mp) = node;
+        break;
+    default:
+        ERTS_INTERNAL_ERROR("Unexpected monitor type");
+        type = am_undefined;
+        ERL_MESSAGE_FROM(mp) = am_undefined;
+        break;
+    }
+
+    ERL_MESSAGE_TERM(mp) = TUPLE5(hp, am_DOWN, ref,
+                                  type, from, reason);
+    hp += 6;
+
+    ERL_MESSAGE_TOKEN(mp) = NIL;
+#ifdef USE_VM_PROBES
+    ERL_MESSAGE_DT_UTAG(mp) = NIL;
+#endif
+    /* Replace original signal with the exit message... */
+    convert_to_msg(c_p, sig, mp, next_nm_sig);
+
+    cnt += 4;
+
+    erts_proc_notify_new_message(c_p, ERTS_PROC_LOCK_MAIN);
+
+    return cnt;
+}
+
+static ERTS_INLINE int
+convert_to_nodedown_messages(Process *c_p,
+                             ErtsMessage *sig,
+                             ErtsMonitorData *mdp,
+                             ErtsMessage ***next_nm_sig)
+{
+    int cnt = 1;
+    Uint n;
+    ErtsMonitorDataExtended *mdep = (ErtsMonitorDataExtended *) mdp;
+
+    ASSERT((mdp->origin.flags & ERTS_ML_FLGS_SAME)
+           == (mdp->target.flags & ERTS_ML_FLGS_SAME));
+    ASSERT(mdp->origin.flags & ERTS_ML_FLG_EXTENDED);
+
+    n = mdep->u.refc;
+
+    if (n == 0)
+        remove_nm_sig(c_p, sig, next_nm_sig);
+    else {
+        Uint i;
+        ErtsMessage *nd_first = NULL;
+        ErtsMessage *nd_last = NULL;
+        ErtsProcLocks locks = ERTS_PROC_LOCK_MAIN;
+        Eterm node = mdep->dist->nodename;
+
+        ASSERT(is_atom(node));
+        ASSERT(n > 0);
+
+        for (i = 0; i < n; i++) {
+            ErtsMessage *mp;
+            ErlOffHeap *ohp;
+            Eterm *hp;
+
+            mp = erts_alloc_message_heap(c_p, &locks, 3, &hp, &ohp);
+
+            ERL_MESSAGE_TERM(mp) = TUPLE2(hp, am_nodedown, node);
+            ERL_MESSAGE_FROM(mp) = am_system;
+            ERL_MESSAGE_TOKEN(mp) = NIL;
+#ifdef USE_VM_PROBES
+            ERL_MESSAGE_DT_UTAG(mp) = NIL;
+#endif
+            mp->next = nd_first;
+            nd_first = mp;
+            if (!nd_last)
+                nd_last = mp;
+            cnt++;
+        }
+
+        if (locks != ERTS_PROC_LOCK_MAIN)
+            erts_proc_unlock(c_p, locks & ~ERTS_PROC_LOCK_MAIN);
+
+        /* Replace signal with 'nodedown' messages */
+        convert_to_msgs(c_p, sig, n, nd_first, nd_last, next_nm_sig);
+
+        erts_proc_notify_new_message(c_p, ERTS_PROC_LOCK_MAIN);
+    }
+    return cnt;
+}
+
+static int 
+handle_nodedown(Process *c_p,
+                ErtsMessage *sig,
+                ErtsMonitorData *mdp,
+                ErtsMessage ***next_nm_sig)
+{
+    ErtsMonitorDataExtended *mdep = (ErtsMonitorDataExtended *) mdp;
+    ErtsMonitor *omon = &mdp->origin;
+    int not_in_subtab = !(omon->flags & ERTS_ML_FLG_IN_SUBTABLE);
+    int cnt = 1;
+
+    ASSERT(erts_monitor_is_in_table(omon));
+
+    if (not_in_subtab & !mdep->uptr.node_monitors)
+        erts_monitor_tree_delete(&ERTS_P_MONITORS(c_p), omon);
+    else if (not_in_subtab) {
+        ErtsMonitor *sub_mon;
+        ErtsMonitorDataExtended *sub_mdep;
+        sub_mon = erts_monitor_list_last(mdep->uptr.node_monitors);
+        ASSERT(sub_mon);
+        erts_monitor_list_delete(&mdep->uptr.node_monitors, sub_mon);
+        sub_mon->flags &= ~ERTS_ML_FLG_IN_SUBTABLE;
+        sub_mdep = (ErtsMonitorDataExtended *) erts_monitor_to_data(sub_mon);
+        ASSERT(!sub_mdep->uptr.node_monitors);
+        sub_mdep->uptr.node_monitors = mdep->uptr.node_monitors;
+        mdep->uptr.node_monitors = NULL;
+        erts_monitor_tree_replace(&ERTS_P_MONITORS(c_p), omon, sub_mon);
+        cnt += 2;
+    }
+    else {
+        ErtsMonitorDataExtended *top_mdep;
+        ErtsMonitor *top_mon;
+        ASSERT(is_atom(omon->other.item));
+        ASSERT(!mdep->uptr.node_monitors);
+        top_mon = erts_monitor_tree_lookup(ERTS_P_MONITORS(c_p),
+                                           omon->other.item);
+        ASSERT(top_mon);
+        top_mdep = (ErtsMonitorDataExtended *) erts_monitor_to_data(top_mon);
+        ASSERT(top_mdep->uptr.node_monitors);
+        erts_monitor_list_delete(&top_mdep->uptr.node_monitors, omon);
+        omon->flags &= ~ERTS_ML_FLG_IN_SUBTABLE;
+        cnt += 3;
+    }
+
+    return cnt + convert_to_nodedown_messages(c_p, sig, mdp, next_nm_sig);
+}
+
+static void
+handle_persistent_mon_msg(Process *c_p, Uint16 type,
+                          ErtsMonitor *mon, ErtsMessage *sig,
+                          Eterm msg, ErtsMessage ***next_nm_sig)
+{
+    convert_prepared_sig_to_msg(c_p, sig, msg, next_nm_sig);
+
+    switch (type) {
+
+    case ERTS_MON_TYPE_TIME_OFFSET:
+        ASSERT(mon->type == ERTS_MON_TYPE_TIME_OFFSET);
+        break;
+
+    case ERTS_MON_TYPE_NODES: {
+        ErtsMonitorDataExtended *mdep;
+        Uint n;
+        ASSERT(mon->type == ERTS_MON_TYPE_NODES);
+        mdep = (ErtsMonitorDataExtended *) erts_monitor_to_data(mon);
+        ERTS_ML_ASSERT(mdep->u.refc > 0);
+        n = mdep->u.refc;
+        n--;
+        if (n > 0) {
+            ErtsProcLocks locks = ERTS_PROC_LOCK_MAIN;
+            ErtsMessage *first = NULL, *prev, *last;
+            Uint hsz = size_object(msg);
+            Uint i;
+
+            for (i = 0; i < n; i++) {
+                Eterm *hp;
+                ErlOffHeap *ohp;
+
+                last = erts_alloc_message_heap(c_p, &locks, hsz, &hp, &ohp);
+
+                if (!first)
+                    first = last;
+                else
+                    prev->next = last;
+                prev = last;
+
+                ERL_MESSAGE_TERM(last) = copy_struct(msg, hsz, &hp, ohp);
+
+#ifdef USE_VM_PROBES
+                ASSERT(is_immed(ERL_MESSAGE_DT_UTAG(sig)));
+                ERL_MESSAGE_DT_UTAG(last) = ERL_MESSAGE_DT_UTAG(sig);
+#endif
+                ASSERT(is_immed(ERL_MESSAGE_TOKEN(sig)));
+                ERL_MESSAGE_TOKEN(last) = ERL_MESSAGE_TOKEN(sig);
+                ASSERT(is_immed(ERL_MESSAGE_FROM(sig)));
+                ERL_MESSAGE_FROM(last) = ERL_MESSAGE_FROM(sig);
+
+            }
+            if (locks != ERTS_PROC_LOCK_MAIN)
+                erts_proc_unlock(c_p, locks & ~ERTS_PROC_LOCK_MAIN);
+            insert_messages(c_p, &sig->next, first, last, n, next_nm_sig);
+        }
+        break;
+    }
+
+    default:
+        ERTS_INTERNAL_ERROR("Invalid type");
+        break;
+    }
+
+    erts_proc_notify_new_message(c_p, ERTS_PROC_LOCK_MAIN);
+}
+
+static void
+group_leader_reply(Process *c_p, Eterm to, Eterm ref, int success)
+{
+    Process *rp = erts_proc_lookup(to);
+
+    if (rp) {
+        ErtsProcLocks locks;
+        Uint sz;
+        Eterm *hp, msg, ref_cpy, result;
+        ErlOffHeap *ohp;
+        ErtsMessage *mp;
+
+        ASSERT(is_internal_ref(ref));
+
+        locks = c_p == rp ? ERTS_PROC_LOCK_MAIN : 0;
+        sz = size_object(ref);
+
+        mp = erts_alloc_message_heap(rp, &locks, sz+3,
+                                     &hp, &ohp);
+
+        ref_cpy = copy_struct(ref, sz, &hp, ohp);
+        result = success ? am_true : am_badarg;
+        msg = TUPLE2(hp, ref_cpy, result);
+
+        erts_queue_message(rp, locks, mp, msg, am_system);
+
+        if (c_p == rp)
+            locks &= ~ERTS_PROC_LOCK_MAIN;
+
+        if (locks)
+            erts_proc_unlock(rp, locks);
+    }
+}
+
+static void
+handle_group_leader(Process *c_p, ErtsSigGroupLeader *sgl)
+{
+    erts_aint_t flags;
+
+    flags = erts_atomic_read_band_nob(&sgl->flags, ~ERTS_SIG_GL_FLG_ACTIVE);
+    if (flags & ERTS_SIG_GL_FLG_ACTIVE) {
+        int res = erts_set_group_leader(c_p, sgl->group_leader);
+        if (is_internal_pid(sgl->reply_to))
+            group_leader_reply(c_p, sgl->reply_to, sgl->ref, res);
+    }
+
+    flags = erts_atomic_read_band_nob(&sgl->flags, ~ERTS_SIG_GL_FLG_RECEIVER);
+    if ((flags & ~ERTS_SIG_GL_FLG_RECEIVER) == 0)
+        destroy_sig_group_leader(sgl);
+}
+
+
+/*
+ * Called in order to handle incoming signals.
+ */
+
+int
+erts_proc_sig_handle_incoming(Process *c_p, erts_aint32_t *statep,
+                              int *redsp, int max_reds, int local_only)
+{
+    Eterm tag;
+    erts_aint32_t state;
+    int cnt, limit, abs_lim, msg_tracing;
+    ErtsMessage *sig, ***next_nm_sig;
+    ErtsSigRecvTracing tracing;
+
+    ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE(c_p);
+    ERTS_LC_ASSERT(ERTS_PROC_LOCK_MAIN == erts_proc_lc_my_proc_locks(c_p));
+
+    if (local_only)
+        state = -1; /* can never be a valid state... */
+    else {
+        state = erts_atomic32_read_nob(&c_p->state);
+        if (ERTS_PSFLG_SIG_IN_Q & state) {
+            erts_proc_lock(c_p, ERTS_PROC_LOCK_MSGQ);
+            erts_proc_sig_fetch(c_p);
+            erts_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ);
+        }
+    }
+
+    limit = *redsp;
+    *redsp = 0;
+
+    if (!c_p->sig_qs.cont) {
+        if (state == -1)
+            *statep = erts_atomic32_read_nob(&c_p->state);
+        else
+            *statep = state;
+        return !0;
+    }
+
+    next_nm_sig = &c_p->sig_qs.nmsigs.next;
+
+    setup_tracing_state(c_p, &tracing);
+    msg_tracing = tracing.messages.active;
+
+    limit *= ERTS_SIG_REDS_CNT_FACTOR;
+    abs_lim = ERTS_SIG_REDS_CNT_FACTOR*max_reds;
+    if (limit > abs_lim)
+        limit = abs_lim;
+
+    cnt = 0;
+
+    do {
+
+        if (msg_tracing) {
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+            if (handle_msg_tracing(c_p, &tracing, next_nm_sig) != 0) {
+                ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+                break; /* tracing limit or end... */
+            }
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+        }
+
+        if (!*next_nm_sig)
+            break;
+
+        sig = **next_nm_sig;
+
+        ASSERT(sig);
+        ASSERT(ERTS_SIG_IS_NON_MSG(sig));
+
+        tag = ((ErtsSignal *) sig)->common.tag;
+ 
+        switch (ERTS_PROC_SIG_OP(tag)) {
+
+        case ERTS_SIG_Q_OP_EXIT:
+        case ERTS_SIG_Q_OP_EXIT_LINKED: {
+            int exited;
+
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+
+            cnt += handle_exit_signal(c_p, &tracing, sig,
+                                      next_nm_sig, &exited);
+
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+
+            if (exited)
+                goto stop; /* terminated by signal */
+            /* ignored or converted to exit message... */
+            break;
+        }
+
+        case ERTS_SIG_Q_OP_MONITOR_DOWN: {
+            Uint16 type = ERTS_PROC_SIG_TYPE(tag);
+            ErtsExitSignalData *xsigd = NULL;
+            ErtsMonitorData *mdp = NULL;
+            ErtsMonitor *omon = NULL, *tmon = NULL;
+
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+
+            switch (type) {
+            case ERTS_MON_TYPE_DIST_PROC:
+            case ERTS_MON_TYPE_PROC:
+            case ERTS_MON_TYPE_PORT:
+                tmon = (ErtsMonitor *) sig;
+                ASSERT(erts_monitor_is_target(tmon));
+                ASSERT(!erts_monitor_is_in_table(tmon));
+                mdp = erts_monitor_to_data(tmon);
+                if (erts_monitor_is_in_table(&mdp->origin)) {
+                    omon = &mdp->origin;
+                    erts_monitor_tree_delete(&ERTS_P_MONITORS(c_p),
+                                             omon);
+                    cnt += convert_to_down_message(c_p, sig, mdp,
+                                                   type, next_nm_sig);
+                }
+                break;
+            case ERTS_SIG_Q_TYPE_GEN_EXIT:
+                xsigd = get_exit_signal_data(sig);
+                omon = erts_monitor_tree_lookup(ERTS_P_MONITORS(c_p),
+                                                xsigd->u.ref);
+                if (omon) {
+                    ASSERT(erts_monitor_is_origin(omon));
+                    if (omon->type == ERTS_MON_TYPE_DIST_PROC) {
+                        mdp = erts_monitor_to_data(omon);
+                        if (erts_monitor_dist_delete(&mdp->target))
+                            tmon = &mdp->target;
+                    }
+                    erts_monitor_tree_delete(&ERTS_P_MONITORS(c_p),
+                                             omon);
+                    cnt += convert_prepared_down_message(c_p, sig,
+                                                         xsigd->message,
+                                                         next_nm_sig);
+                }
+                break;
+            case ERTS_MON_TYPE_NODE:
+                tmon = (ErtsMonitor *) sig;
+                ASSERT(erts_monitor_is_target(tmon));
+                ASSERT(!erts_monitor_is_in_table(tmon));
+                mdp = erts_monitor_to_data(tmon);
+                if (erts_monitor_is_in_table(&mdp->origin)) {
+                    omon = &mdp->origin;
+                    cnt += handle_nodedown(c_p, sig, mdp, next_nm_sig);
+                }
+                break;
+            default:
+                ERTS_INTERNAL_ERROR("invalid monitor type");
+                break;
+            }
+
+            if (omon) {
+                if (tmon)
+                    erts_monitor_release_both(mdp);
+                else
+                    erts_monitor_release(omon);
+            }
+            else {
+                remove_nm_sig(c_p, sig, next_nm_sig);
+                if (xsigd) {
+                    sig->next = NULL;
+                    erts_cleanup_messages(sig);
+                }
+                if (tmon)
+                    erts_monitor_release(tmon);
+            }
+
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+            break;
+        }
+
+        case ERTS_SIG_Q_OP_PERSISTENT_MON_MSG: {
+            Uint16 type = ERTS_PROC_SIG_TYPE(tag);
+            ErtsMonitor *mon;
+            Eterm msg;
+            Eterm key;
+
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+
+            key = get_persist_mon_msg(sig, &msg);
+
+            cnt++;
+            mon = erts_monitor_tree_lookup(ERTS_P_MONITORS(c_p), key);
+            if (mon) {
+                ASSERT(erts_monitor_is_origin(mon));
+                handle_persistent_mon_msg(c_p, type, mon, sig,
+                                          msg, next_nm_sig);
+            }
+            else {
+                cnt++;
+                remove_nm_sig(c_p, sig, next_nm_sig);
+                sig->next = NULL;
+                erts_cleanup_messages(sig);
+            }
+
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+            break;
+        }
+
+        case ERTS_SIG_Q_OP_MONITOR: {
+            ErtsMonitor *mon = (ErtsMonitor *) sig;
+
+            ASSERT(erts_monitor_is_target(mon));
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+
+            remove_nm_sig(c_p, sig, next_nm_sig);
+
+            if (mon->type == ERTS_MON_TYPE_DIST_PROC)
+                erts_monitor_tree_insert(&ERTS_P_MONITORS(c_p), mon);
+            else
+                erts_monitor_list_insert(&ERTS_P_LT_MONITORS(c_p), mon);
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+            break;
+        }
+
+        case ERTS_SIG_Q_OP_DEMONITOR: {
+            Uint16 type = ERTS_PROC_SIG_TYPE(tag);
+
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+
+            remove_nm_sig(c_p, sig, next_nm_sig);
+
+            if (type == ERTS_SIG_Q_TYPE_DIST_PROC_DEMONITOR) {
+                ErtsMonitor *tmon;
+                ErtsSigDistProcDemonitor *dmon;
+                dmon = (ErtsSigDistProcDemonitor *) sig;
+                tmon = erts_monitor_tree_lookup(ERTS_P_MONITORS(c_p), dmon->ref);
+                destroy_dist_proc_demonitor(dmon);
+                cnt++;
+                if (tmon) {
+                    ErtsMonitorData *mdp = erts_monitor_to_data(tmon);
+                    ASSERT(erts_monitor_is_target(tmon));
+                    erts_monitor_tree_delete(&ERTS_P_MONITORS(c_p), tmon);
+                    if (!erts_monitor_dist_delete(&mdp->origin))
+                        erts_monitor_release(tmon);
+                    else
+                        erts_monitor_release_both(mdp);
+                    cnt += 2;
+                }
+            }
+            else {
+                ErtsMonitor *omon = (ErtsMonitor *) sig;
+                ErtsMonitorData *mdp = erts_monitor_to_data(omon);
+                ASSERT(omon->type == type);
+                ASSERT(erts_monitor_is_origin(omon));
+                ASSERT(!erts_monitor_is_in_table(omon));
+                if (!erts_monitor_is_in_table(&mdp->target))
+                    erts_monitor_release(omon);
+                else {
+                    ErtsMonitor *tmon = &mdp->target;
+                    ASSERT(tmon->type == type);
+                    if (type == ERTS_MON_TYPE_DIST_PROC)
+                        erts_monitor_tree_delete(&ERTS_P_MONITORS(c_p), tmon);
+                    else {
+                        erts_monitor_list_delete(&ERTS_P_LT_MONITORS(c_p), tmon);
+                        if (type == ERTS_MON_TYPE_RESOURCE) {
+                            erts_nif_demonitored((ErtsResource *) tmon->other.ptr);
+                            cnt++;
+                        }
+                    }
+                    erts_monitor_release_both(mdp);
+                    cnt++;
+                }
+                cnt++;
+            }
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+            break;
+        }
+
+        case ERTS_SIG_Q_OP_LINK: {
+            ErtsLink *rlnk, *lnk = (ErtsLink *) sig;
+
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+
+            remove_nm_sig(c_p, sig, next_nm_sig);
+            rlnk = erts_link_tree_insert_addr_replace(&ERTS_P_LINKS(c_p),
+                                                      lnk);
+            if (!rlnk) {
+                if (tracing.procs)
+                    getting_linked(c_p, lnk->other.item);
+            }
+            else {
+                if (rlnk->type != ERTS_LNK_TYPE_DIST_PROC)
+                    erts_link_release(rlnk);
+                else {
+                    ErtsLinkData *ldp;
+                    ErtsLink *dlnk = erts_link_to_other(rlnk, &ldp);
+                    if (erts_link_dist_delete(dlnk))
+                        erts_link_release_both(ldp);
+                    else
+                        erts_link_release(rlnk);
+                }
+            }
+
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+            break;
+        }
+
+        case ERTS_SIG_Q_OP_UNLINK: {
+            Uint16 type = ERTS_PROC_SIG_TYPE(tag);
+            ErtsLinkData *ldp;
+            ErtsLink *llnk;
+
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+
+            remove_nm_sig(c_p, sig, next_nm_sig);
+            if (type == ERTS_SIG_Q_TYPE_DIST_LINK) {
+                ErtsSigDistLinkOp *sdlnk = (ErtsSigDistLinkOp *) sig;
+                ASSERT(type == ERTS_SIG_Q_TYPE_DIST_LINK);
+                ASSERT(is_external_pid(sdlnk->remote));
+                llnk = erts_link_tree_lookup(ERTS_P_LINKS(c_p), sdlnk->remote);
+                if (llnk) {
+                    ErtsLink *dlnk = erts_link_to_other(llnk, &ldp);
+                    erts_link_tree_delete(&ERTS_P_LINKS(c_p), llnk);
+                    if (erts_link_dist_delete(dlnk))
+                        erts_link_release_both(ldp);
+                    else
+                        erts_link_release(llnk);
+                    cnt += 8;
+                    if (tracing.procs)
+                        getting_unlinked(c_p, sdlnk->remote);
+                }
+                destroy_sig_dist_link_op(sdlnk);
+                cnt++;
+            }
+            else {
+                ErtsLinkData *ldp;
+                ErtsLink *dlnk, *slnk;
+                slnk = (ErtsLink *) sig;
+                llnk = erts_link_to_other(slnk, &ldp);
+                dlnk = erts_link_tree_key_delete(&ERTS_P_LINKS(c_p), llnk);
+                if (!dlnk)
+                    erts_link_release(slnk);
+                else {
+                    if (tracing.procs)
+                        getting_unlinked(c_p, llnk->other.item);
+                    if (dlnk == llnk)
+                        erts_link_release_both(ldp);
+                    else {
+                        erts_link_release(slnk);
+                        erts_link_release(dlnk);
+                    }
+                }
+                cnt += 2;
+            }
+
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+            break;
+        }
+
+        case ERTS_SIG_Q_OP_GROUP_LEADER: {
+            ErtsSigGroupLeader *sgl = (ErtsSigGroupLeader *) sig;
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+            remove_nm_sig(c_p, sig, next_nm_sig);
+            handle_group_leader(c_p, sgl);
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+            break;
+        }
+
+        case ERTS_SIG_Q_OP_TRACE_CHANGE_STATE: {
+            Uint16 type = ERTS_PROC_SIG_TYPE(tag);
+
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+            msg_tracing = handle_trace_change_state(c_p, &tracing,
+                                                    type, sig,
+                                                    next_nm_sig);
+            ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, &tracing, next_nm_sig);
+            
+            break;
+        }
+
+        default:
+            ERTS_INTERNAL_ERROR("Unknown signal");
+            break;
+        }
+
+        cnt++;
+
+    } while (cnt <= limit || stretch_limit(c_p, &tracing, abs_lim, &limit));
+
+stop: {
+        int deferred_save, deferred_saved_last, res;
+
+        deferred_saved_last = !!(c_p->flags & F_DEFERRED_SAVED_LAST);
+        deferred_save = 0;
+
+        if (!deferred_saved_last)
+            deferred_save = 0;
+        else {
+            if (c_p->sig_qs.saved_last == &c_p->sig_qs.cont) {
+                c_p->sig_qs.saved_last = c_p->sig_qs.last;
+                c_p->flags &= ~F_DEFERRED_SAVED_LAST;
+                deferred_saved_last = deferred_save = 0;
+            }
+            else {
+                if (c_p->sig_qs.save == c_p->sig_qs.last)
+                    deferred_save = !0;
+                else
+                    deferred_save = 0;
+            }
+        }
+
+        ASSERT(c_p->sig_qs.saved_last != &c_p->sig_qs.cont);
+
+        if (ERTS_UNLIKELY(msg_tracing != 0)) {
+            /*
+             * All messages that has been traced should
+             * be moved to inner queue. Next signal in
+             * middle queue should either be next message
+             * to trace or next non-message signal.
+             */
+            ASSERT(tracing.messages.next);
+            if (*next_nm_sig) {
+                if (*next_nm_sig == tracing.messages.next)
+                    *next_nm_sig = &c_p->sig_qs.cont;
+                if (c_p->sig_qs.nmsigs.last == tracing.messages.next)
+                    c_p->sig_qs.nmsigs.last = &c_p->sig_qs.cont;
+                *statep = erts_atomic32_read_nob(&c_p->state);
+            }
+            else {
+                ASSERT(!c_p->sig_qs.nmsigs.next);
+                c_p->sig_qs.nmsigs.last = NULL;
+                state = erts_atomic32_read_band_nob(&c_p->state,
+                                                    ~ERTS_PSFLG_SIG_Q);
+                state &= ~ERTS_PSFLG_SIG_Q;
+                *statep = state;
+            }
+
+            if (tracing.messages.next != &c_p->sig_qs.cont) {
+                *c_p->sig_qs.last = c_p->sig_qs.cont;
+                c_p->sig_qs.last = tracing.messages.next;
+
+                c_p->sig_qs.cont = *tracing.messages.next;
+                if (!c_p->sig_qs.cont)
+                    c_p->sig_qs.cont_last = &c_p->sig_qs.cont;
+                *c_p->sig_qs.last = NULL;
+            }
+
+            res = !c_p->sig_qs.cont;
+        }
+        else if (*next_nm_sig) {
+            /*
+             * All messages prior to next non-message
+             * signal should be moved to inner queue.
+             * Next non-message signal to handle should
+             * be first in middle queue.
+             */
+            ASSERT(**next_nm_sig);
+            if (*next_nm_sig != &c_p->sig_qs.cont) {
+                *c_p->sig_qs.last = c_p->sig_qs.cont;
+                c_p->sig_qs.last = *next_nm_sig;
+
+                c_p->sig_qs.cont = **next_nm_sig;
+                if (c_p->sig_qs.nmsigs.last == *next_nm_sig)
+                    c_p->sig_qs.nmsigs.last = &c_p->sig_qs.cont;
+                *next_nm_sig = &c_p->sig_qs.cont;
+                *c_p->sig_qs.last = NULL;
+            }
+
+            ASSERT(c_p->sig_qs.cont);
+
+            *statep = erts_atomic32_read_nob(&c_p->state);
+
+            res = 0;
+        }
+        else {
+            /*
+             * All non-message signals handled. All
+             * messages should be moved to inner queue.
+             * Middle queue should be empty.
+             */
+            ASSERT(!c_p->sig_qs.nmsigs.next);
+            c_p->sig_qs.nmsigs.last = NULL;
+
+            if (c_p->sig_qs.cont_last != &c_p->sig_qs.cont) {
+                ASSERT(!*c_p->sig_qs.last);
+                *c_p->sig_qs.last = c_p->sig_qs.cont;
+                c_p->sig_qs.last = c_p->sig_qs.cont_last;
+                ASSERT(!*c_p->sig_qs.last);
+
+                c_p->sig_qs.cont_last = &c_p->sig_qs.cont;
+                c_p->sig_qs.cont = NULL;
+            }
+
+            ASSERT(!c_p->sig_qs.cont);
+
+            state = erts_atomic32_read_band_nob(&c_p->state,
+                                                ~ERTS_PSFLG_SIG_Q);
+            state &= ~ERTS_PSFLG_SIG_Q;
+            *statep = state;
+            res = !0;
+        }
+
+        if (deferred_saved_last
+            && (c_p->sig_qs.saved_last == &c_p->sig_qs.cont)) {
+            c_p->sig_qs.saved_last = c_p->sig_qs.last;
+            c_p->flags &= ~F_DEFERRED_SAVED_LAST;
+            if (deferred_save)
+                c_p->sig_qs.save = c_p->sig_qs.saved_last;
+        }
+        else if (!res) {
+            if (deferred_save) {
+                c_p->sig_qs.save = c_p->sig_qs.last;
+                ASSERT(!PEEK_MESSAGE(c_p));
+            }
+        }
+        else {
+            c_p->flags &= ~F_DEFERRED_SAVED_LAST;
+            if (deferred_save)
+                c_p->sig_qs.save = c_p->sig_qs.saved_last;
+        }
+
+        ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE(c_p);
+
+        *redsp = cnt/4 + 1;
+
+        return res;
+    }
+}
+
+static int
+stretch_limit(Process *c_p, ErtsSigRecvTracing *tp,
+              int abs_lim, int *limp)
+{
+    int lim;
+    /*
+     * Stretch limit up to a maximum of 'abs_lim' if
+     * there currently are no messages available to
+     * inspect by 'receive' and it might be possible
+     * to get messages available by processing
+     * signals (or trace messages).
+     */
+
+    lim = *limp;
+    ASSERT(abs_lim >= lim);
+    if (abs_lim == lim)
+        return 0;
+
+    if (!(c_p->flags & F_DEFERRED_SAVED_LAST)) {
+        ErtsSignal *sig;
+
+        if (PEEK_MESSAGE(c_p))
+            return 0;
+        sig = (ErtsSignal *) c_p->sig_qs.cont;
+        if (!sig)
+            return 0; /* No signals to process available... */
+        if (ERTS_SIG_IS_MSG(sig) && tp->messages.next != &c_p->sig_qs.cont)
+            return 0;
+    }
+
+    lim += ERTS_SIG_REDS_CNT_FACTOR*100;
+    if (lim > abs_lim)
+        lim = abs_lim;
+    *limp = lim;
+    return !0;
+}
+
+
+int
+erts_proc_sig_handle_exit(Process *c_p, int *redsp)
+{
+    int cnt, limit;
+    ErtsMessage *sig, ***next_nm_sig;
+
+    ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE(c_p);
+    ERTS_LC_ASSERT(!erts_proc_lc_my_proc_locks(c_p));
+
+    ASSERT(!(ERTS_PSFLG_SIG_IN_Q & erts_atomic32_read_nob(&c_p->state)));
+
+    limit = *redsp;
+    limit *= ERTS_SIG_REDS_CNT_FACTOR;
+
+    *redsp = 1;
+
+    next_nm_sig = &c_p->sig_qs.nmsigs.next;
+
+    if (!*next_nm_sig) {
+        ASSERT(!c_p->sig_qs.nmsigs.last);
+        return !0; /* done... */
+    }
+
+    cnt = 0;
+
+    ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, NULL, next_nm_sig);
+
+    do {
+        Eterm tag;
+        Uint16 type;
+        int op;
+
+        sig = **next_nm_sig;
+
+        ASSERT(sig);
+        ASSERT(ERTS_SIG_IS_NON_MSG(sig));
+
+        tag = ((ErtsSignal *) sig)->common.tag;
+        type = ERTS_PROC_SIG_TYPE(tag);
+        op = ERTS_PROC_SIG_OP(tag);
+
+        remove_nm_sig(c_p, sig, next_nm_sig);
+ 
+        ERTS_PROC_SIG_HDBG_PRIV_CHKQ(c_p, NULL, next_nm_sig);
+
+        cnt++;
+
+        switch (op) {
+
+        case ERTS_SIG_Q_OP_EXIT:
+        case ERTS_SIG_Q_OP_EXIT_LINKED:
+        case ERTS_SIG_Q_OP_MONITOR_DOWN:
+            switch (type) {
+            case ERTS_SIG_Q_TYPE_GEN_EXIT:
+                sig->next = NULL;
+                erts_cleanup_messages(sig);
+                break;
+            case ERTS_LNK_TYPE_PORT:
+            case ERTS_LNK_TYPE_PROC:
+            case ERTS_LNK_TYPE_DIST_PROC:
+                erts_link_release((ErtsLink *) sig);
+                break;
+            case ERTS_MON_TYPE_PORT:
+            case ERTS_MON_TYPE_PROC:
+            case ERTS_MON_TYPE_DIST_PROC:
+            case ERTS_MON_TYPE_NODE:
+                erts_monitor_release((ErtsMonitor *) sig);
+                break;
+            default:
+                ERTS_INTERNAL_ERROR("Unexpected sig type");
+                break;
+            }
+            break;
+
+        case ERTS_SIG_Q_OP_PERSISTENT_MON_MSG:
+            sig->next = NULL;
+            erts_cleanup_messages(sig);
+            break;
+
+        case ERTS_SIG_Q_OP_MONITOR: {
+            ErtsProcExitContext pectxt = {c_p, am_noproc};
+            erts_proc_exit_handle_monitor((ErtsMonitor *) sig,
+                                          (void *) &pectxt);
+            cnt += 4;
+            break;
+        }
+
+        case ERTS_SIG_Q_OP_DEMONITOR:
+            if (type == ERTS_SIG_Q_TYPE_DIST_PROC_DEMONITOR)
+                destroy_dist_proc_demonitor((ErtsSigDistProcDemonitor *) sig);
+            else
+                erts_monitor_release((ErtsMonitor *) sig);
+            break;
+
+        case ERTS_SIG_Q_OP_LINK: {
+            ErtsProcExitContext pectxt = {c_p, am_noproc};
+            erts_proc_exit_handle_link((ErtsLink *) sig, (void *) &pectxt);
+            break;
+        }
+
+        case ERTS_SIG_Q_OP_UNLINK:
+            if (type == ERTS_SIG_Q_TYPE_DIST_LINK)
+                destroy_sig_dist_link_op((ErtsSigDistLinkOp *) sig);
+            else
+                erts_link_release((ErtsLink *) sig);
+            break;
+
+        case ERTS_SIG_Q_OP_GROUP_LEADER: {
+            ErtsSigGroupLeader *sgl = (ErtsSigGroupLeader *) sig;
+            handle_group_leader(c_p, sgl);
+            break;
+        }
+
+        case ERTS_SIG_Q_OP_TRACE_CHANGE_STATE:
+            destroy_trace_info((ErtsSigTraceInfo *) sig);
+            break;
+
+        default:
+            ERTS_INTERNAL_ERROR("Unknown signal");
+            break;
+        }
+
+    } while (cnt >= limit && *next_nm_sig);
+
+    *redsp += cnt / ERTS_SIG_REDS_CNT_FACTOR;
+
+    if (*next_nm_sig)
+        return 0;
+
+    ASSERT(!c_p->sig_qs.nmsigs.next);
+    c_p->sig_qs.nmsigs.last = NULL;
+    (void) erts_atomic32_read_band_nob(&c_p->state,
+                                       ~ERTS_PSFLG_SIG_Q);
+    return !0;
+}
+
+#ifdef USE_VM_PROBES
+#  define ERTS_CLEAR_SEQ_TOKEN(MP)                                      \
+    ERL_MESSAGE_TOKEN((MP)) = ((ERL_MESSAGE_DT_UTAG((MP)) != NIL)       \
+                               ? am_have_dt_utag : NIL)
+#else
+#  define ERTS_CLEAR_SEQ_TOKEN(MP)                                      \
+    ERL_MESSAGE_TOKEN((MP)) = NIL
+#endif
+
+static ERTS_INLINE void
+clear_seq_trace_token(ErtsMessage *sig)
+{
+    if (ERTS_SIG_IS_MSG((ErtsSignal *) sig))
+        ERTS_CLEAR_SEQ_TOKEN(sig);
+    else {
+        Uint tag;
+        Uint16 op, type;
+
+        tag = ((ErtsSignal *) sig)->common.tag;
+        type = ERTS_PROC_SIG_TYPE(tag);
+        op = ERTS_PROC_SIG_OP(tag);
+
+        switch (op) {
+
+        case ERTS_SIG_Q_OP_EXIT:
+        case ERTS_SIG_Q_OP_EXIT_LINKED:
+        case ERTS_SIG_Q_OP_MONITOR_DOWN:
+            switch (type) {
+            case ERTS_SIG_Q_TYPE_GEN_EXIT:
+                ERTS_CLEAR_SEQ_TOKEN(sig);
+                break;
+            case ERTS_LNK_TYPE_PORT:
+            case ERTS_LNK_TYPE_PROC:
+            case ERTS_LNK_TYPE_DIST_PROC:
+            case ERTS_MON_TYPE_PORT:
+            case ERTS_MON_TYPE_PROC:
+            case ERTS_MON_TYPE_DIST_PROC:
+            case ERTS_MON_TYPE_NODE:
+                break;
+            default:
+                ERTS_INTERNAL_ERROR("Unexpected sig type");
+                break;
+            }
+            break;
+
+        case ERTS_SIG_Q_OP_PERSISTENT_MON_MSG:
+            ERTS_CLEAR_SEQ_TOKEN(sig);
+            break;
+
+        case ERTS_SIG_Q_OP_MONITOR:
+        case ERTS_SIG_Q_OP_DEMONITOR:
+        case ERTS_SIG_Q_OP_LINK:
+        case ERTS_SIG_Q_OP_UNLINK:
+        case ERTS_SIG_Q_OP_TRACE_CHANGE_STATE:
+            break;
+
+        default:
+            ERTS_INTERNAL_ERROR("Unknown signal");
+            break;
+        }
+    }
+}
+
+void
+erts_proc_sig_clear_seq_trace_tokens(Process *c_p)
+{
+    ASSERT(erts_thr_progress_is_blocking());
+    erts_proc_sig_fetch(c_p);
+    ERTS_FOREACH_SIG_PRIVQS(c_p, sig, clear_seq_trace_token(sig));
+}
+
+Uint
+erts_proc_sig_signal_size(ErtsSignal *sig)
+{
+    Eterm tag;
+    Uint16 type;
+    int op;
+    Uint size = 0;
+
+    ASSERT(sig);
+    ASSERT(ERTS_SIG_IS_NON_MSG(sig));
+
+    tag = sig->common.tag;
+    type = ERTS_PROC_SIG_TYPE(tag);
+    op = ERTS_PROC_SIG_OP(tag);
+
+    switch (op) {
+    case ERTS_SIG_Q_OP_EXIT:
+    case ERTS_SIG_Q_OP_EXIT_LINKED:
+    case ERTS_SIG_Q_OP_MONITOR_DOWN:
+        switch (type) {
+        case ERTS_SIG_Q_TYPE_GEN_EXIT:
+            size = ((ErtsMessage *) sig)->hfrag.alloc_size;
+            size *= sizeof(Eterm);
+            size += sizeof(ErtsMessage) - sizeof(Eterm);
+            break;
+        case ERTS_LNK_TYPE_PORT:
+        case ERTS_LNK_TYPE_PROC:
+        case ERTS_LNK_TYPE_DIST_PROC:
+            size = erts_link_size((ErtsLink *) sig);
+            break;
+        case ERTS_MON_TYPE_PORT:
+        case ERTS_MON_TYPE_PROC:
+        case ERTS_MON_TYPE_DIST_PROC:
+        case ERTS_MON_TYPE_NODE:
+            size = erts_monitor_size((ErtsMonitor *) sig);
+        default:
+            ERTS_INTERNAL_ERROR("Unexpected sig type");
+            break;
+        }
+        break;
+
+    case ERTS_SIG_Q_OP_PERSISTENT_MON_MSG:
+        size = ((ErtsMessage *) sig)->hfrag.alloc_size;
+        size *= sizeof(Eterm);
+        size += sizeof(ErtsMessage) - sizeof(Eterm);
+        break;
+
+    case ERTS_SIG_Q_OP_DEMONITOR:
+        if (type == ERTS_SIG_Q_TYPE_DIST_PROC_DEMONITOR) {
+            size = NC_HEAP_SIZE(((ErtsSigDistProcDemonitor *) sig)->ref);
+            size--;
+            size *= sizeof(Eterm);
+            size += sizeof(ErtsSigDistProcDemonitor);
+            break;
+        }
+        /* Fall through... */
+
+    case ERTS_SIG_Q_OP_MONITOR:
+        size = erts_monitor_size((ErtsMonitor *) sig);
+        break;
+
+    case ERTS_SIG_Q_OP_UNLINK:
+        if (type == ERTS_SIG_Q_TYPE_DIST_LINK) {
+            size = NC_HEAP_SIZE(((ErtsSigDistLinkOp *) sig)->remote);
+            size--;
+            size *= sizeof(Eterm);
+            size += sizeof(ErtsSigDistLinkOp);
+            break;
+        }
+        /* Fall through... */
+
+    case ERTS_SIG_Q_OP_LINK:
+        size = erts_link_size((ErtsLink *) sig);
+        break;
+
+    case ERTS_SIG_Q_OP_GROUP_LEADER: {
+        ErtsSigGroupLeader *sgl = (ErtsSigGroupLeader *) sig;
+        size = size_object(sgl->group_leader);
+        size += size_object(sgl->ref);
+        size *= sizeof(Eterm);
+        size += sizeof(ErtsSigGroupLeader) - sizeof(Eterm);
+        break;
+    }
+
+    case ERTS_SIG_Q_OP_TRACE_CHANGE_STATE:
+        size = sizeof(ErtsSigTraceInfo);
+        break;
+
+    default:
+        ERTS_INTERNAL_ERROR("Unknown signal");
+        break;
+    }
+
+    return size;
+}
+
+int
+erts_proc_sig_receive_helper(Process *c_p,
+                             int fcalls,
+                             int neg_o_reds,
+                             ErtsMessage **msgpp,
+                             int *get_outp)
+{
+    ErtsMessage *msgp;
+    int reds, consumed_reds, left_reds, max_reds;
+
+    /*
+     * Called from the loop-rec instruction when receive
+     * has reached end of inner (private) queue. This function
+     * tries to move more messages into the inner queue
+     * for the receive to handle. This by, processing the
+     * middle (private) queue and/or moving signals from
+     * the outer (public) queue into the middle queue.
+     *
+     * If this function succeeds in making more messages
+     * available in the inner queue, *msgpp points to next
+     * message. If *msgpp is set to NULL when:
+     * -- process became exiting. *get_outp is set to a
+     *    value greater than zero.
+     * -- process needs to yield. *get_outp is set to a
+     *    value less than zero.
+     * -- no more messages exist in any of the queues.
+     *    *get_outp is set to zero and the message queue
+     *    lock remains locked. This so the process can
+     *    make its way to the appropriate wait instruction
+     *    without racing with new incoming messages.
+     */
+
+    ASSERT(erts_proc_lc_my_proc_locks(c_p) == ERTS_PROC_LOCK_MAIN);
+    ASSERT(!ERTS_PROC_IS_EXITING(c_p));
+    ASSERT(!*msgpp);
+
+    left_reds = fcalls - neg_o_reds;
+    consumed_reds = 0;
+
+    while (!0) {
+        erts_aint32_t state;
+
+        if (!c_p->sig_qs.cont) {
+
+            consumed_reds += 4;
+            left_reds -= 4;
+            erts_proc_lock(c_p, ERTS_PROC_LOCK_MSGQ);
+            if (c_p->sig_inq.first)
+                erts_proc_sig_fetch(c_p);
+            /*
+             * Messages may have been moved directly to
+             * inner queue...
+             */
+            msgp = PEEK_MESSAGE(c_p);
+            if (msgp) {
+                erts_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ);
+                *get_outp = 0;
+                *msgpp = msgp;
+                return consumed_reds;
+            }
+
+            if (!c_p->sig_qs.cont) {
+                /*
+                 * No messages! Return with message queue
+                 * locked and let the process continue
+                 * to wait instruction...
+                 */
+                *get_outp = 0;
+                *msgpp = NULL;
+                return consumed_reds;
+            }
+            erts_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ);
+
+            if (left_reds <= 0) {
+                *get_outp = -1; /* yield */
+                *msgpp = NULL;
+
+                ASSERT(consumed_reds >= (fcalls - neg_o_reds));
+                return consumed_reds;
+            }
+
+            /* handle newly arrived signals... */
+        }
+
+        reds = ERTS_SIG_HANDLE_REDS_MAX_PREFERED;
+#ifdef DEBUG
+        /* test that it works also with very few reds */
+        max_reds = left_reds;
+        if (reds > left_reds)
+            reds = left_reds;
+#else
+        /* At least work preferred amount of reds... */
+        max_reds = left_reds;
+        if (max_reds < reds)
+            max_reds = reds;
+#endif
+        (void) erts_proc_sig_handle_incoming(c_p, &state, &reds,
+                                             max_reds, !0);
+        consumed_reds += reds;
+        left_reds -= reds;
+        /* we may have exited by an incoming signal... */
+        if (state & ERTS_PSFLG_EXITING) {
+            /*
+             * Process need to schedule out in order
+             * to terminate. Prepare this a bit...
+             */
+            ASSERT(c_p->flags & F_DELAY_GC);
+
+            c_p->flags &= ~F_DELAY_GC;
+            c_p->arity = 0;
+            c_p->current = NULL;
+            *get_outp = 1;
+            *msgpp = NULL;
+            return consumed_reds;
+        }
+
+        msgp = PEEK_MESSAGE(c_p);
+        if (msgp) {
+            *get_outp = 0;
+            *msgpp = msgp;
+            return consumed_reds;
+        }
+
+        if (left_reds <= 0) {
+            *get_outp = -1; /* yield */
+            *msgpp = NULL;
+
+            ASSERT(consumed_reds >= (fcalls - neg_o_reds));
+            return consumed_reds;
+        }
+
+        ASSERT(!c_p->sig_qs.cont);
+        /* Go fetch again... */
+    }
+}
+
+static int
+handle_trace_change_state(Process *c_p,
+                          ErtsSigRecvTracing *tracing,
+                          Uint16 type,
+                          ErtsMessage *sig,
+                          ErtsMessage ***next_nm_sig)
+{
+    ErtsSigTraceInfo *trace_info = (ErtsSigTraceInfo *) sig;
+    ErtsMessage **next = *next_nm_sig;
+    int msgs_active, old_msgs_active = !!tracing->messages.active;
+
+    ASSERT(sig == *next);
+
+    erts_proc_lock(c_p, ERTS_PROC_LOCKS_ALL_MINOR);
+
+    ERTS_TRACE_FLAGS(c_p) |= trace_info->flags_on;
+    ERTS_TRACE_FLAGS(c_p) &= ~trace_info->flags_off;
+    if (is_value(trace_info->tracer))
+        erts_tracer_replace(&c_p->common, trace_info->tracer);
+
+    erts_proc_unlock(c_p, ERTS_PROC_LOCKS_ALL_MINOR);
+
+    remove_nm_sig(c_p, sig, next_nm_sig);
+    destroy_trace_info(trace_info);
+    /*
+     * Adjust tracing state according to modifications made by
+     * the trace info signal...
+     */
+    adjust_tracing_state(c_p, tracing, 0);
+    msgs_active = !!tracing->messages.active;
+
+    if (old_msgs_active ^ msgs_active) {
+        if (msgs_active) {
+            ASSERT(!tracing->messages.next);
+            tracing->messages.next = next;
+        }
+        else {
+            ASSERT(tracing->messages.next);
+            tracing->messages.next = NULL;
+        }
+    }
+
+    ASSERT(!msgs_active || tracing->messages.next);
+
+    return msgs_active;
+}
+
+static void
+getting_unlinked(Process *c_p, Eterm unlinker)
+{
+    trace_proc(c_p, ERTS_PROC_LOCK_MAIN, c_p,
+               am_getting_unlinked, unlinker);
+}
+
+static void
+getting_linked(Process *c_p, Eterm linker)
+{
+    trace_proc(c_p, ERTS_PROC_LOCK_MAIN, c_p,
+               am_getting_linked, linker);
+}
+
+static ERTS_INLINE void
+handle_message_enqueued_tracing(Process *c_p,
+                                ErtsSigRecvTracing *tracing,
+                                ErtsMessage *msg)
+{
+    ASSERT(ERTS_SIG_IS_INTERNAL_MSG(msg));
+
+#if defined(USE_VM_PROBES)
+    if (tracing->messages.vm_probes && DTRACE_ENABLED(message_queued)) {
+        Sint tok_label = 0;
+        Sint tok_lastcnt = 0;
+        Sint tok_serial = 0;
+        Eterm seq_trace_token = ERL_MESSAGE_TOKEN(msg);
+
+        if (seq_trace_token != NIL && is_tuple(seq_trace_token)) {
+            tok_label = signed_val(SEQ_TRACE_T_LABEL(seq_trace_token));
+            tok_lastcnt = signed_val(SEQ_TRACE_T_LASTCNT(seq_trace_token));
+            tok_serial = signed_val(SEQ_TRACE_T_SERIAL(seq_trace_token));
+        }
+        /* Message intentionally not passed... */
+        DTRACE6(message_queued,
+                tracing->messages.receiver_name,
+                size_object(ERL_MESSAGE_TERM(msg)),
+                c_p->sig_qs.len,
+                tok_label, tok_lastcnt, tok_serial);
+    }
+#endif
+
+    if (tracing->messages.receive_trace && tracing->messages.event->on) {
+        ASSERT(IS_TRACED(c_p));
+        trace_receive(c_p,
+                      ERL_MESSAGE_FROM(msg),
+                      ERL_MESSAGE_TERM(msg),
+                      tracing->messages.event);
+    }
+}
+
+static int
+handle_msg_tracing(Process *c_p, ErtsSigRecvTracing *tracing,
+                   ErtsMessage ***next_nm_sig)
+{
+    ErtsMessage **next_sig, *sig;
+    int cnt = 0, limit = ERTS_PROC_SIG_TRACE_COUNT_LIMIT;
+
+    ASSERT(tracing->messages.next);
+    next_sig = tracing->messages.next;
+    sig = *next_sig;
+
+    /*
+     * Receive tracing active. Handle all messages
+     * until next non-message signal...
+     */
+
+    while (sig && ERTS_SIG_IS_MSG(sig)) {
+        if (cnt > limit) {
+            tracing->messages.next = next_sig;
+            return -1; /* Yield... */
+        }
+        if (ERTS_SIG_IS_EXTERNAL_MSG(sig)) {
+            cnt++;
+            if (!erts_decode_dist_message(c_p, ERTS_PROC_LOCK_MAIN,
+                                          sig, 0)) {
+                /* Bad dist message; remove it... */
+                remove_mq_m_sig(c_p, sig, next_sig, next_nm_sig);
+                sig = *next_sig;
+                continue;
+            }
+        }
+        handle_message_enqueued_tracing(c_p, tracing, sig);
+        cnt++;
+
+        next_sig = &(*next_sig)->next;
+        sig = *next_sig;
+    }
+
+    tracing->messages.next = next_sig;
+
+    if (!sig) {
+        ASSERT(!*next_nm_sig);
+        return 1; /* end... */
+    }
+
+    ASSERT(*next_nm_sig);
+    ASSERT(**next_nm_sig == sig);
+
+    /* Next signal a non-message signal... */
+    ASSERT(ERTS_SIG_IS_NON_MSG(sig));
+
+    /*
+     * Return and handle the non-message signal...
+     */
+
+    return 0;
+}
+
+/*
+ * ERTS_INSPECT_MSGQ_KEEP_OH_MSGS == 0 will move off heap messages
+ * into the heap of the inspected process if off_heap_message_queue
+ * is false when process_info(_, messages) is called. That is, the
+ * following GC will have more data in the rootset compared to the
+ * scenario when process_info(_, messages) had not been called.
+ *
+ * ERTS_INSPECT_MSGQ_KEEP_OH_MSGS != 0 will keep off heap messages
+ * off heap when process_info(_, messages) is called regardless of
+ * the off_heap_message_queue setting of the process. That is, it
+ * will change the following execution of the process as little as
+ * possible.
+ */
+#define ERTS_INSPECT_MSGQ_KEEP_OH_MSGS 1
+
+Uint
+erts_proc_sig_prep_msgq_for_inspection(Process *c_p, Process *rp,
+                                       ErtsProcLocks rp_locks,
+                                       ErtsMessageInfo *mip)
+{
+    Uint tot_heap_size;
+    ErtsMessage *mp, **mpp;
+    Sint i;
+    int self_on_heap;
+
+    /*
+     * Prepare the message queue for inspection
+     * by process_info().
+     *
+     *
+     * - Decode all messages on external format
+     * - Remove all corrupt dist messages from queue
+     * - Save pointer to, and heap size need of each
+     *   message in the mip array.
+     * - Return total heap size need for all messages
+     *   that needs to be copied.
+     *
+     * If ERTS_INSPECT_MSGQ_KEEP_OH_MSGS == 0:
+     * - In case off heap messages is disabled and
+     *   we are inspecting our own queue, move all
+     *   off heap data into the heap.
+     */
+
+    /*
+     * All non-message signals *need* to have been
+     * handled before calling this functions...
+     */
+    ASSERT(!rp->sig_qs.cont);
+    ASSERT(!rp->sig_qs.nmsigs.next && !rp->sig_qs.nmsigs.last);
+
+    self_on_heap = c_p == rp && !(c_p->flags & F_OFF_HEAP_MSGQ);
+
+    tot_heap_size = 0;
+    i = 0;
+    mpp = &rp->sig_qs.first;
+    mp = rp->sig_qs.first;
+    while (mp) {
+	Eterm msg = ERL_MESSAGE_TERM(mp);
+
+	mip[i].size = 0;
+
+	if (ERTS_SIG_IS_EXTERNAL_MSG(mp)) {
+	    /* decode it... */
+	    if (mp->data.attached)
+		erts_decode_dist_message(rp, rp_locks, mp,
+					 ERTS_INSPECT_MSGQ_KEEP_OH_MSGS);
+
+	    msg = ERL_MESSAGE_TERM(mp);
+
+	    if (is_non_value(msg)) {
+		ErtsMessage *bad_mp = mp;
+		/*
+		 * Bad distribution message; remove
+		 * it from the queue...
+		 */
+		ASSERT(!mp->data.attached);
+
+		ASSERT(*mpp == bad_mp);
+
+                remove_iq_m_sig(rp, mp, mpp);
+
+                mp = *mpp;
+
+		bad_mp->next = NULL;
+		erts_cleanup_messages(bad_mp);
+		continue;
+	    }
+	}
+
+	ASSERT(is_value(msg));
+
+#if ERTS_INSPECT_MSGQ_KEEP_OH_MSGS
+	if (is_not_immed(msg) && (!self_on_heap || mp->data.attached)) {
+	    Uint sz = size_object(msg);
+	    mip[i].size = sz;
+	    tot_heap_size += sz;
+	}
+#else
+	if (self_on_heap) {
+	    if (mp->data.attached) {
+		ErtsMessage *tmp = NULL;
+		if (mp->data.attached != ERTS_MSG_COMBINED_HFRAG) {
+		    erts_link_mbuf_to_proc(rp, mp->data.heap_frag);
+		    mp->data.attached = NULL;
+		}
+		else {
+		    /*
+		     * Need to replace the message reference since
+		     * we will get references to the message data
+		     * from the heap...
+		     */
+		    ErtsMessage **mpp;
+		    tmp = erts_alloc_message(0, NULL);
+		    sys_memcpy((void *) tmp->m, (void *) mp->m,
+			       sizeof(Eterm)*ERL_MESSAGE_REF_ARRAY_SZ); 
+		    mpp = i == 0 ? &rp->sig_qs.first : &mip[i-1].msgp->next;
+		    erts_msgq_replace_msg_ref(&rp->msg, tmp, mpp);
+		    erts_save_message_in_proc(rp, mp);
+		    mp = tmp;
+		}
+	    }
+	}
+	else if (is_not_immed(msg)) {
+	    Uint sz = size_object(msg);
+	    mip[i].size = sz;
+	    tot_heap_size += sz;
+	}
+
+#endif
+
+	mip[i].msgp = mp;
+	i++;
+        mpp = &mp->next;
+	mp = mp->next;
+    }
+
+    return tot_heap_size;
+}
+
+static ERTS_INLINE void
+move_msg_to_heap(Process *c_p, ErtsMessage *mp)
+{
+    /*
+     * We leave not yet decoded distribution messages
+     * as they are in the queue since it is not
+     * possible to determine a maximum size until
+     * actual decoding...
+     *
+     * We also leave combined messages as they are...
+     */
+    if (ERTS_SIG_IS_INTERNAL_MSG(mp)
+        && mp->data.attached
+        && mp->data.attached != ERTS_MSG_COMBINED_HFRAG) {
+        ErlHeapFragment *bp;
+
+        bp = erts_message_to_heap_frag(mp);
+
+        if (bp->next)
+            erts_move_multi_frags(&c_p->htop, &c_p->off_heap, bp,
+                                  mp->m, ERL_MESSAGE_REF_ARRAY_SZ, 0);
+        else
+            erts_copy_one_frag(&c_p->htop, &c_p->off_heap, bp,
+                               mp->m, ERL_MESSAGE_REF_ARRAY_SZ);
+
+        mp->data.heap_frag = NULL;
+        free_message_buffer(bp);
+    }
+}
+
+void
+erts_proc_sig_move_msgs_to_heap(Process *c_p)
+{
+    ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE(c_p);
+
+    ERTS_FOREACH_SIG_PRIVQS(c_p, sig, move_msg_to_heap(c_p, sig));
+
+    ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE(c_p);
+}
+
+
+BIF_RETTYPE
+erts_internal_dirty_process_handle_signals_1(BIF_ALIST_1)
+{
+    erts_aint32_t state, dirty, noproc;
+    int busy;
+    Process *rp;
+
+    if (BIF_P != erts_dirty_process_signal_handler
+        && BIF_P != erts_dirty_process_signal_handler_high
+        && BIF_P != erts_dirty_process_signal_handler_max)
+        BIF_ERROR(BIF_P, EXC_NOTSUP);
+
+    if (is_not_internal_pid(BIF_ARG_1))
+        BIF_RET(am_false);
+
+    rp = erts_proc_lookup_raw(BIF_ARG_1);
+    if (!rp)
+        BIF_RET(am_noproc);
+
+    state = erts_atomic32_read_nob(&rp->state);
+    dirty = (state & (ERTS_PSFLG_DIRTY_RUNNING
+                      | ERTS_PSFLG_DIRTY_RUNNING_SYS));
+    if (!dirty)
+        BIF_RET(am_normal);
+
+    busy = erts_proc_trylock(rp, ERTS_PROC_LOCK_MAIN) == EBUSY;
+
+    state = erts_atomic32_read_mb(&rp->state);
+    noproc = (state & ERTS_PSFLG_FREE);
+    dirty = (state & (ERTS_PSFLG_DIRTY_RUNNING
+                      | ERTS_PSFLG_DIRTY_RUNNING_SYS));
+
+    if (busy) {
+        if (noproc)
+            BIF_RET(am_noproc);
+        if (dirty)
+            BIF_RET(am_more); /* try again... */
+        BIF_RET(am_normal); /* will handle signals itself... */
+    }
+    else {
+        erts_aint32_t state;
+        int done;
+        Eterm res = am_false;
+        int reds = 0;
+
+        if (noproc)
+            res = am_noproc;
+        else if (!dirty)
+            res = am_normal; /* will handle signals itself... */
+        else {
+            reds = ERTS_BIF_REDS_LEFT(BIF_P);
+            done = erts_proc_sig_handle_incoming(rp, &state, &reds,
+                                                 reds, 0);
+            if (done || (state & ERTS_PSFLG_EXITING))
+                res = am_ok;
+            else
+                res = am_more;
+        }
+
+        erts_proc_unlock(rp, ERTS_PROC_LOCK_MAIN);
+
+        if (reds)
+            BUMP_REDS(BIF_P, reds);
+
+        BIF_RET(res);
+    }
+}
+
+static void
+debug_foreach_sig_heap_frags(ErlHeapFragment *hfrag,
+                             void (*oh_func)(ErlOffHeap *, void *),
+                             void *arg)
+{
+    ErlHeapFragment *hf = hfrag;
+    while (hf) {
+        oh_func(&(hf->off_heap), arg);
+        hf = hf->next;
+    }
+}
+
+static void
+debug_foreach_sig_fake_oh(Eterm term,
+                          void (*oh_func)(ErlOffHeap *, void *),
+                          void *arg)
+{
+    if (is_external(term)) {
+        ErlOffHeap oh;
+        oh.overhead = 0;
+        oh.first = ((struct erl_off_heap_header *)
+                    (char *) external_thing_ptr(term));
+        ASSERT(!oh.first->next);
+        oh_func(&oh, arg);
+    }
+
+}
+
+void
+erts_proc_sig_debug_foreach_sig(Process *c_p,
+                                void (*msg_func)(ErtsMessage *, void *),
+                                void (*oh_func)(ErlOffHeap *, void *),
+                                void (*mon_func)(ErtsMonitor *, void *),
+                                void (*lnk_func)(ErtsLink *, void *),
+                                void *arg)
+{
+    ErtsMessage *queue[] = {c_p->sig_qs.first, c_p->sig_qs.cont, c_p->sig_inq.first};
+    int qix;
+
+    for (qix = 0; qix < sizeof(queue)/sizeof(queue[0]); qix++) {
+        ErtsMessage *sig;
+        for (sig = queue[qix]; sig; sig = sig->next) {
+            
+            if (ERTS_SIG_IS_MSG(sig))
+                msg_func(sig, arg);
+            else {
+                Eterm tag;
+                Uint16 type;
+                int op;
+
+                ASSERT(sig);
+                ASSERT(ERTS_SIG_IS_NON_MSG(sig));
+
+                tag = ((ErtsSignal *) sig)->common.tag;
+                type = ERTS_PROC_SIG_TYPE(tag);
+                op = ERTS_PROC_SIG_OP(tag);
+
+                switch (op) {
+
+                case ERTS_SIG_Q_OP_EXIT:
+                case ERTS_SIG_Q_OP_EXIT_LINKED:
+                case ERTS_SIG_Q_OP_MONITOR_DOWN:
+                    switch (type) {
+                    case ERTS_SIG_Q_TYPE_GEN_EXIT:
+                        debug_foreach_sig_heap_frags(&sig->hfrag, oh_func, arg);
+                        break;
+                    case ERTS_LNK_TYPE_PORT:
+                    case ERTS_LNK_TYPE_PROC:
+                    case ERTS_LNK_TYPE_DIST_PROC:
+                        lnk_func((ErtsLink *) sig, arg);
+                        break;
+                    case ERTS_MON_TYPE_PORT:
+                    case ERTS_MON_TYPE_PROC:
+                    case ERTS_MON_TYPE_DIST_PROC:
+                    case ERTS_MON_TYPE_NODE:
+                        mon_func((ErtsMonitor *) sig, arg);
+                        break;
+                    default:
+                        ERTS_INTERNAL_ERROR("Unexpected sig type");
+                        break;
+                    }
+                    break;
+
+                case ERTS_SIG_Q_OP_PERSISTENT_MON_MSG:
+                    debug_foreach_sig_heap_frags(&sig->hfrag, oh_func, arg);
+                    break;
+
+                case ERTS_SIG_Q_OP_DEMONITOR:
+                    if (type == ERTS_SIG_Q_TYPE_DIST_PROC_DEMONITOR) {
+                        debug_foreach_sig_fake_oh(((ErtsSigDistProcDemonitor *) sig)->ref,
+                                                  oh_func, arg);
+                        break;
+                    }
+                    /* Fall through... */
+
+                case ERTS_SIG_Q_OP_MONITOR:
+                    mon_func((ErtsMonitor *) sig, arg);
+                    break;
+
+                case ERTS_SIG_Q_OP_UNLINK:
+                    if (type == ERTS_SIG_Q_TYPE_DIST_LINK) {
+                        debug_foreach_sig_fake_oh(((ErtsSigDistLinkOp *) sig)->remote,
+                                                  oh_func, arg);
+                        break;
+                    }
+                    /* Fall through... */
+
+                case ERTS_SIG_Q_OP_LINK:
+                    lnk_func((ErtsLink *) sig, arg);
+                    break;
+
+                case ERTS_SIG_Q_OP_GROUP_LEADER: {
+                    ErtsSigGroupLeader *sgl = (ErtsSigGroupLeader *) sig;
+                    oh_func(&sgl->oh, arg);
+                    break;
+                }
+
+                case ERTS_SIG_Q_OP_TRACE_CHANGE_STATE:
+                    break;
+
+                default:
+                    ERTS_INTERNAL_ERROR("Unknown signal");
+                    break;
+                }
+
+            }
+        }
+    }
+}
+
+#ifdef ERTS_PROC_SIG_HARD_DEBUG
+
+static void
+chk_eterm(Process *c_p, int privq, ErtsMessage *mp, Eterm term)
+{
+    ErlHeapFragment *bp;
+    Eterm *ptr = NULL;
+
+    switch (primary_tag(term)) {
+    case TAG_PRIMARY_IMMED1:
+        return;
+    case TAG_PRIMARY_LIST:
+        ptr = list_val(term);
+        ERTS_ASSERT(!is_header(CAR(ptr)));
+        ERTS_ASSERT(!is_header(CDR(ptr)));
+        break;
+    case TAG_PRIMARY_BOXED:
+        ptr = boxed_val(term);
+        ERTS_ASSERT(is_header(*ptr));
+        break;
+    case TAG_PRIMARY_HEADER:
+    default:
+        ERTS_INTERNAL_ERROR("Not valid term");
+        break;
+    }
+
+    if (erts_is_literal(term, ptr))
+        return;
+
+    for (bp = erts_message_to_heap_frag(mp); bp; bp = bp->next) {
+        if (bp->mem <= ptr && ptr < bp->mem + bp->used_size)
+            return;
+        bp = bp->next;
+    }
+
+    ERTS_ASSERT(privq);
+    ASSERT(erts_dbg_within_proc(ptr, c_p, NULL));
+}
+
+static Sint
+proc_sig_hdbg_check_queue(Process *proc,
+                          int privq,
+                          ErtsMessage **sig_next,
+                          ErtsMessage **sig_last,
+                          ErtsMessage **sig_nm_next,
+                          ErtsMessage **sig_nm_last,
+                          ErtsSigRecvTracing *tracing,
+                          int *found_saved_last_p,
+                          erts_aint32_t sig_psflg)
+{
+    ErtsMessage **next, *sig, **nm_next, **nm_last;
+    int last_nm_sig_found, nm_sigs = 0, found_next_trace = 0,
+        found_save = 0, last_sig_found = 0, found_saved_last = 0;
+    Sint msg_len = 0;
+    ErtsMessage **next_trace = tracing ? tracing->messages.next : NULL;
+    ErtsMessage **save = proc->sig_qs.save;
+    ErtsMessage **saved_last = proc->sig_qs.saved_last;
+
+
+    nm_next = sig_nm_next;
+    nm_last = sig_nm_last;
+    next = sig_next;
+    sig = *sig_next;
+
+    last_nm_sig_found = !nm_last;
+    if (last_nm_sig_found)
+        ERTS_ASSERT(!nm_next);
+    else
+        ERTS_ASSERT(nm_next);
+
+    while (1) {
+        ErtsSignal *nm_sig;
+
+        if (next == sig_last) {
+            ASSERT(!*next);
+            last_sig_found = 1;
+        }
+
+        if (next == save)
+            found_save = 1;
+
+        if (next == saved_last)
+            found_saved_last = 1;
+
+        if (next == next_trace) {
+            found_next_trace = 1;
+            ERTS_ASSERT(nm_sigs == 0);
+        }
+
+        while (sig && ERTS_SIG_IS_MSG(sig)) {
+            int i;
+            if (ERTS_SIG_IS_EXTERNAL_MSG(sig))
+                i = 1;
+            else
+                i = 0;
+            for (; i < ERL_MESSAGE_REF_ARRAY_SZ; i++)
+                chk_eterm(proc, privq, sig, sig->m[i]);
+
+            msg_len++;
+            next = &sig->next;
+            sig = sig->next;
+
+            if (next == sig_last) {
+                ASSERT(!*next);
+                last_sig_found = 1;
+            }
+
+            if (next == save)
+                found_save = 1;
+
+            if (next == saved_last)
+                found_saved_last = 1;
+
+            if (next == next_trace) {
+                found_next_trace = 1;
+                ERTS_ASSERT(nm_sigs == 0);
+            }
+        }
+
+        if (!sig)
+            break;
+
+        nm_sigs++;
+
+        ERTS_ASSERT(!last_nm_sig_found);
+        ERTS_ASSERT(ERTS_SIG_IS_NON_MSG(sig));
+
+        nm_sig = (ErtsSignal *) sig;
+
+        ERTS_ASSERT(nm_next == next);
+
+        if (nm_last == next) {
+            ASSERT(!nm_sig->common.specific.next);
+            last_nm_sig_found = 1;
+        }
+
+        nm_next = nm_sig->common.specific.next;
+        next = &nm_sig->common.next;
+        sig = nm_sig->common.next;
+
+    }
+
+    if (!privq) {
+        /* outer queue */
+        ERTS_ASSERT(!found_save);
+        ERTS_ASSERT(!found_saved_last);
+    }
+    else if (privq > 0) {
+        /* middle queue */
+        ERTS_ASSERT(!next_trace || found_next_trace);
+        ERTS_ASSERT(!found_save);
+        if (!found_saved_last_p) {
+            ERTS_ASSERT(!found_saved_last
+                        || (proc->flags & F_DEFERRED_SAVED_LAST));
+        }
+        else {
+            if (*found_saved_last_p) {
+                ERTS_ASSERT(!found_saved_last);
+                ERTS_ASSERT(!(proc->flags & F_DEFERRED_SAVED_LAST));
+            }
+            else if (saved_last) {
+                ERTS_ASSERT(found_saved_last);
+                ERTS_ASSERT(proc->flags & F_DEFERRED_SAVED_LAST);
+            }
+            *found_saved_last_p |= found_saved_last;
+        }
+    }
+    else {
+        /* inner queue */
+        ERTS_ASSERT(!found_next_trace);
+        ERTS_ASSERT(nm_sigs == 0);
+        ERTS_ASSERT(found_save);
+        ERTS_ASSERT(!saved_last
+                    || (found_saved_last
+                        || (proc->flags & F_DEFERRED_SAVED_LAST)));
+        if (found_saved_last_p)
+            *found_saved_last_p |= found_saved_last;
+    }
+
+    ERTS_ASSERT(last_nm_sig_found);
+    ERTS_ASSERT(last_sig_found);
+
+    if (sig_psflg != ERTS_PSFLG_FREE) {
+        erts_aint32_t state = erts_atomic32_read_nob(&proc->state);
+        ERTS_ASSERT(nm_sigs ? !!(state & sig_psflg) : !(state & sig_psflg));
+    }
+
+    return msg_len;
+}
+
+void
+erts_proc_sig_hdbg_check_priv_queue(Process *p, char *what, char *file, int line)
+{
+    int found_saved_last = 0;
+    Sint len1, len2;
+    ERTS_LC_ASSERT(erts_thr_progress_is_blocking()
+                   || ERTS_PROC_IS_EXITING(p)
+                   || (ERTS_PROC_LOCK_MAIN
+                       & erts_proc_lc_my_proc_locks(p)));
+    len1 = proc_sig_hdbg_check_queue(p,
+                                     -1,
+                                     &p->sig_qs.first,
+                                     p->sig_qs.last,
+                                     NULL,
+                                     NULL,
+                                     NULL,
+                                     &found_saved_last,
+                                     ERTS_PSFLG_FREE);
+    len2 = proc_sig_hdbg_check_queue(p,
+                                     1,
+                                     &p->sig_qs.cont,
+                                     p->sig_qs.cont_last,
+                                     p->sig_qs.nmsigs.next,
+                                     p->sig_qs.nmsigs.last,
+                                     NULL,
+                                     &found_saved_last,
+                                     ERTS_PSFLG_SIG_Q);
+    if (p->sig_qs.saved_last)
+        ERTS_ASSERT(found_saved_last);
+    ERTS_ASSERT(p->sig_qs.len == len1 + len2);
+}
+
+void
+erts_proc_sig_hdbg_check_in_queue(Process *p, char *what, char *file, int line)
+{
+    Sint len;
+    ERTS_LC_ASSERT(erts_thr_progress_is_blocking()
+                   || ERTS_PROC_IS_EXITING(p)
+                   || (ERTS_PROC_LOCK_MSGQ
+                       & erts_proc_lc_my_proc_locks(p)));
+    len = proc_sig_hdbg_check_queue(p,
+                                    0,
+                                    &p->sig_inq.first,
+                                    p->sig_inq.last,
+                                    p->sig_inq.nmsigs.next,
+                                    p->sig_inq.nmsigs.last,
+                                    NULL,
+                                    NULL,
+                                    ERTS_PSFLG_SIG_IN_Q);
+    ASSERT(p->sig_inq.len == len);
+}
+
+#endif
diff --git a/erts/emulator/beam/erl_proc_sig_queue.h b/erts/emulator/beam/erl_proc_sig_queue.h
new file mode 100644
index 0000000000..433e30ce4a
--- /dev/null
+++ b/erts/emulator/beam/erl_proc_sig_queue.h
@@ -0,0 +1,665 @@
+/*
+ * %CopyrightBegin%
+ * 
+ * Copyright Ericsson AB 2018. All Rights Reserved.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * 
+ * %CopyrightEnd%
+ */
+
+/*
+ * Description:	Process signal queue implementation.
+ *
+ *              Currently the following signals are handled:
+ *              - Messages
+ *              - Exit
+ *              - Monitor
+ *              - Demonitor
+ *              - Monitor down
+ *              - Persistent monitor message
+ *              - Link
+ *              - Unlink
+ *              - Group leader
+ *              - Trace change
+ *
+ *              The signal queue consists of three parts:
+ *              - Outer queue (sig_inq field in process struct)
+ *              - Middle queue (sig_qs field in process struct)
+ *              - Inner queue (sig_qs field in process struct)
+ *
+ *              Incoming signals are placed in the outer queue
+ *              by other processes, ports, or by the runtime system
+ *              itself. This queue is protected by the msgq process
+ *              lock and may be accessed by any other entity. While
+ *              a signal is located in the outer queue, it is still
+ *              in transit between sender and receiver.
+ *
+ *              The middle and the inner queues are private to the
+ *              receiving process and can only be accessed while
+ *              holding the main process lock. The signal changes
+ *              from being in transit to being received while in
+ *              the middle queue. Non-message signals are handled
+ *              immediately upon reception while message signals
+ *              are moved into the inner queue.
+ *
+ *              In the outer and middle queues both message signals
+ *              and non-message signals are mixed. Signals in these
+ *              queues are referenced using two single linked lists.
+ *              One single linked list that go through all signals
+ *              in the queue and another single linked list that
+ *              goes through only non-message signals. The list
+ *              through the non-message signals is used for fast
+ *              access to these signals in the middle queue, since
+ *              these should be handled immediately upon reception.
+ *
+ *              The inner queue consists only of one single linked
+ *              list through the message signals. A receive
+ *              expression can only operate on messages once they
+ *              have entered the inner queue.
+ *
+ * Author: 	Rickard Green
+ */
+
+#ifndef ERTS_PROC_SIG_QUEUE_H_TYPE__
+#define ERTS_PROC_SIG_QUEUE_H_TYPE__
+
+#if 0
+#  define ERTS_PROC_SIG_HARD_DEBUG
+#endif
+
+struct erl_mesg;
+
+typedef struct {
+    struct erl_mesg *next;
+    union {
+        struct erl_mesg **next;
+        void *attachment;
+    } specific;
+    Eterm tag;
+} ErtsSignalCommon;
+
+#define ERTS_SIG_HANDLE_REDS_MAX_PREFERED (CONTEXT_REDS/40)
+
+#ifdef ERTS_PROC_SIG_HARD_DEBUG
+#  define ERTS_HDBG_CHECK_SIGNAL_IN_QUEUE(P)       \
+    ERTS_HDBG_CHECK_SIGNAL_IN_QUEUE__((P), "")
+#  define ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE(P) \
+    ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE__((P), "")
+#  define ERTS_HDBG_CHECK_SIGNAL_IN_QUEUE__(P, What)   \
+    erts_proc_sig_hdbg_check_in_queue((P), (What), __FILE__, __LINE__)
+#  define ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE__(P, What)   \
+    erts_proc_sig_hdbg_check_priv_queue((P), (What), __FILE__, __LINE__)
+struct process;
+void erts_proc_sig_hdbg_check_priv_queue(struct process *c_p, char *what,
+                                         char *file, int line);
+void erts_proc_sig_hdbg_check_in_queue(struct process *c_p, char *what,
+                                       char *file, int line);
+#else
+#  define ERTS_HDBG_CHECK_SIGNAL_IN_QUEUE(P)
+#  define ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE(P)
+#  define ERTS_HDBG_CHECK_SIGNAL_IN_QUEUE__(P, What)
+#define ERTS_HDBG_CHECK_SIGNAL_PRIV_QUEUE__(P, What)
+#endif
+
+#endif
+
+#if !defined(ERTS_PROC_SIG_QUEUE_H__) && !defined(ERTS_PROC_SIG_QUEUE_TYPE_ONLY)
+#define ERTS_PROC_SIG_QUEUE_H__
+
+struct dist_entry_;
+
+/*
+ * Send operations of currently supported process signals follow...
+ */
+
+/**
+ *
+ * @brief Send an exit signal to a process.
+ *
+ *
+ * @param[in]     c_p           Pointer to process struct of
+ *                              currently executing process.
+ *
+ * @param[in]     from          Identifier of sender.
+ *
+ * @param[in]     to            Identifier of local process
+ *                              to send signal to.
+ *
+ * @param[in]     reason        Exit reason.
+ *
+ * @param[in]     token         Seq trace token.
+ *
+ * @param[in]     normal_kills  If non-zero, also normal exit
+ *                              reason will kill the receiver
+ *                              if it is not trapping exit.
+ *
+ */
+void
+erts_proc_sig_send_exit(Process *c_p, Eterm from, Eterm to,
+                        Eterm reason, Eterm token, int normal_kills);
+
+/**
+ *
+ * @brief Send an exit signal due to broken link to a process.
+ *
+ *
+ * @param[in]     c_p           Pointer to process struct of
+ *                              currently executing process.
+ *
+ * @param[in]     from          Identifier of sender.
+ *
+ * @param[in]     lnk           Pointer to link structure
+ *                              from the sending side. It
+ *                              should contain information
+ *                              about receiver.
+ *
+ * @param[in]     reason        Exit reason.
+ *
+ * @param[in]     token         Seq trace token.
+ *
+ */
+void
+erts_proc_sig_send_link_exit(Process *c_p, Eterm from, ErtsLink *lnk,
+                             Eterm reason, Eterm token);
+
+/**
+ *
+ * @brief Send an link signal to a process.
+ *
+ *
+ * @param[in]     c_p           Pointer to process struct of
+ *                              currently executing process.
+ *
+ * @param[in]     to            Identifier of receiver.
+ *
+ * @param[in]     lnk           Pointer to link structure to
+ *                              insert on receiver side.
+ *
+ * @return                      A non-zero value if
+ *                              signal was successfully
+ *                              sent. If a zero, value
+ *                              the signal was not sent
+ *                              due to the receiver not
+ *                              existing. The sender
+ *                              needs to deallocate the
+ *                              link structure.
+ *
+ */
+int
+erts_proc_sig_send_link(Process *c_p, Eterm to, ErtsLink *lnk);
+
+/**
+ *
+ * @brief Send an unlink signal to a process.
+ *
+ *
+ * @param[in]     c_p           Pointer to process struct of
+ *                              currently executing process.
+ *
+ * @param[in]     lnk           Pointer to link structure from
+ *                              the sending side. It should
+ *                              contain information about
+ *                              receiver.
+ */
+void
+erts_proc_sig_send_unlink(Process *c_p, ErtsLink *lnk);
+
+/**
+ *
+ * @brief Send an exit signal due to broken link to a process.
+ *
+ * This function is used instead of erts_proc_sig_send_link_exit()
+ * when the signal arrives via the distribution and
+ * no link structure is available.
+ *
+ * @param[in]     dep           Distribution entry of channel
+ *                              that the signal arrived on.
+ *
+ * @param[in]     from          Identifier of sender.
+ *
+ * @param[in]     to            Identifier of receiver.
+ *
+ * @param[in]     reason        Exit reason.
+ *
+ * @param[in]     token         Seq trace token.
+ *
+ */
+void
+erts_proc_sig_send_dist_link_exit(struct dist_entry_ *dep,
+                                  Eterm from, Eterm to,
+                                  Eterm reason, Eterm token);
+
+/**
+ *
+ * @brief Send an unlink signal to a process.
+ *
+ * This function is used instead of erts_proc_sig_send_unlink()
+ * when the signal arrives via the distribution and
+ * no link structure is available.
+ *
+ * @param[in]     dep           Distribution entry of channel
+ *                              that the signal arrived on.
+ *
+ * @param[in]     from          Identifier of sender.
+ *
+ * @param[in]     to            Identifier of receiver.
+ *
+ */
+void
+erts_proc_sig_send_dist_unlink(struct dist_entry_ *dep,
+                               Eterm from, Eterm to);
+
+/**
+ *
+ * @brief Send a monitor down signal to a process.
+ *
+ * @param[in]     mon           Pointer to target monitor
+ *                              structure from the sending
+ *                              side. It should contain
+ *                              information about receiver.
+ *
+ * @param[in]     reason        Exit reason.
+ *
+ */
+void
+erts_proc_sig_send_monitor_down(ErtsMonitor *mon, Eterm reason);
+
+/**
+ *
+ * @brief Send a demonitor signal to a process.
+ *
+ * @param[in]     mon           Pointer to origin monitor
+ *                              structure from the sending
+ *                              side. It should contain
+ *                              information about receiver.
+ *
+ * @param[in]     reason        Exit reason.
+ *
+ */
+void
+erts_proc_sig_send_demonitor(ErtsMonitor *mon);
+
+/**
+ *
+ * @brief Send a monitor signal to a process.
+ *
+ * @param[in]     mon           Pointer to target monitor
+ *                              structure to insert on
+ *                              receiver side.
+ *
+ * @param[in]     to            Identifier of receiver.
+ *
+ * @return                      A non-zero value if
+ *                              signal was successfully
+ *                              sent. If a zero, value
+ *                              the signal was not sent
+ *                              due to the receiver not
+ *                              existing. The sender
+ *                              needs to deallocate the
+ *                              monitor structure.
+ *
+ */
+int
+erts_proc_sig_send_monitor(ErtsMonitor *mon, Eterm to);
+
+/**
+ *
+ * @brief Send a monitor down signal to a process.
+ *
+ * This function is used instead of erts_proc_sig_send_monitor_down()
+ * when the signal arrives via the distribution and
+ * no link structure is available.
+ *
+ * @param[in]     dep           Pointer to distribution entry
+ *                              of channel that the signal
+ *                              arrived on.
+ *
+ * @param[in]     ref           Reference identifying the monitor.
+ *
+ * @param[in]     from          Identifier of sender.
+ *
+ * @param[in]     to            Identifier of receiver.
+ *
+ * @param[in]     reason        Exit reason.
+ *
+ */
+void
+erts_proc_sig_send_dist_monitor_down(DistEntry *dep, Eterm ref,
+                                     Eterm from, Eterm to,
+                                     Eterm reason);
+
+/**
+ *
+ * @brief Send a demonitor signal to a process.
+ *
+ * This function is used instead of erts_proc_sig_send_demonitor()
+ * when the signal arrives via the distribution and
+ * no monitor structure is available.
+ *
+ * @param[in]     to            Identifier of receiver.
+ *
+ * @param[in]     ref           Reference identifying the monitor.
+ *
+ */
+void
+erts_proc_sig_send_dist_demonitor(Eterm to, Eterm ref);
+
+/**
+ *
+ * @brief Send a persistent monitor triggered signal to a process.
+ *
+ * Used by monitors that are not auto disabled such as for
+ * example 'time_offset' monitors.
+ *
+ * @param[in]     type          Monitor type.
+ *
+ * @param[in]     key           Monitor key.
+ *
+ * @param[in]     from          Identifier of sender.
+ *
+ * @param[in]     to            Identifier of receiver.
+ *
+ * @param[in]     msg           Message template.
+ *
+ * @param[in]     msg_sz        Heap size of message template.
+ *
+ */
+void
+erts_proc_sig_send_persistent_monitor_msg(Uint16 type, Eterm key,
+                                          Eterm from, Eterm to,
+                                          Eterm msg, Uint msg_sz);
+
+/**
+ *
+ * @brief Send a trace change signal to a process.
+ *
+ * @param[in]     to            Identifier of receiver.
+ *
+ * @param[in]     on            Trace flags to enable.
+ *
+ * @param[in]     off           Trace flags to disable.
+ *
+ * @param[in]     tracer        Tracer to set. If the non-value,
+ *                              tracer will not be changed.
+ *
+ */
+void
+erts_proc_sig_send_trace_change(Eterm to, Uint on, Uint off,
+                                Eterm tracer);
+
+/**
+ *
+ * @brief Send a group leader signal to a process.
+ *
+ * Set group-leader of receiving process. If sent locally,
+ * a response message '{Ref, Result}' is sent to the original
+ * sender when performed where Ref is the reference passed
+ * as 'ref' argument, and Result is either 'true' or 'badarg'.
+ *
+ * @param[in]     c_p           Pointer to process struct of
+ *                              currently executing process.
+ *                              NULL if signal arrived via
+ *                              distribution.
+ *
+ * @param[in]     to            Identifier of receiver.
+ *
+ * @param[in]     gl            Identifier of new group leader.
+ *
+ * @param[in]     ref           Reference to use in response
+ *                              message to locally sending
+ *                              process (i.e., c_p when c_p
+ *                              is non-null).
+ *
+ */
+void
+erts_proc_sig_send_group_leader(Process *c_p, Eterm to, Eterm gl,
+                                Eterm ref);
+
+/*
+ * End of send operations of currently supported process signals.
+ */
+
+
+/**
+ *
+ * @brief Handle incoming signals.
+ *
+ * Called by an ordinary scheduler in order to handle incoming
+ * signals for a process. The work is done on the middle part
+ * of the signal queue. The maximum amount of signals handled
+ * is limited by the amount of reductions given when calling.
+ * Note that a reduction does not necessarily map to a signal.
+ *
+ * @param[in]     c_p           Pointer to process struct of
+ *                              currently executing process.
+ *
+ * @param[out]    statep        Pointer to process state after
+ *                              signal handling. May not be NULL.
+ *
+ * @param[in,out] redsp         Pointer to an integer containing
+ *                              reductions. On input, the amount
+ *                              of preferred reductions to be
+ *                              used by the call. On output, the
+ *                              amount of reductions consumed.
+ *
+ * @param[in]     max_reds      Absolute maximum of reductions
+ *                              to use. If the process cannot
+ *                              make progress after the preferred
+ *                              amount of reductions has been
+ *                              consumed, signal handling may
+ *                              proceed up to a maximum of
+ *                              'max_reds' in order to make
+ *                              the process able to proceed
+ *                              with other tasks after handling
+ *                              has finished.
+ *
+ * @param[in]     local_only    If is zero, new signals may be
+ *                              fetched from the outer queue and
+ *                              put in the middle queue before
+ *                              signal handling is performed. If
+ *                              non-zero, no new signals will be
+ *                              fetched before handling begins.
+ *
+ * @return                      Returns a non-zero value, when
+ *                              no more signals to handle in the
+ *                              middle queue remain. A zero
+ *                              return value means that there
+ *                              remains signals in the middle
+ *                              queue.
+ */
+int
+erts_proc_sig_handle_incoming(Process *c_p, erts_aint32_t *statep,
+                              int *redsp, int max_reds,
+                              int local_only);
+
+/**
+ *
+ * @brief Handle remaining signals for an exiting process
+ *
+ * Called as part of termination of a process. It will handle
+ * remaining signals.
+ *
+ * @param[in]     c_p           Pointer to process struct of
+ *                              currently executing process.
+ *
+ * @param[in,out] redsp         Pointer to an integer containing
+ *                              reductions. On input, the amount
+ *                              of maximum reductions to be
+ *                              used by the call. On output, the
+ *                              amount of reductions consumed.
+ *
+ * @return                      Returns a non-zero value, when
+ *                              no more signals to handle in the
+ *                              middle queue remain. A zero
+ *                              return value means that there
+ *                              remains signals in the middle
+ *                              queue.
+ */
+int
+erts_proc_sig_handle_exit(Process *c_p, int *redsp);
+
+/**
+ *
+ * @brief Helper for loop_rec instruction.
+ *
+ * This function should only be called from the loop_rec
+ * instruction (or equivalents). It is called when loop_rec
+ * reach the end of the inner queue (which is the only
+ * part of the signal queue that receive is allowed to
+ * operate on). When called, this function tries to make
+ * more messages available in the inner queue. This by
+ * fetching signals from the outer queue to the middle
+ * queue and/or processing signals in the middle queue.
+ *
+ * @param[in]   c_p             Pointer to process struct of
+ *                              currently executing process.
+ *
+ * @param[in]   fcalls          Content of FCALLS in
+ *                              process_main()
+ *
+ * @param[in]   neg_o_reds      Content of neg_o_reds in
+ *                              process_main()
+ *
+ * @param[out]  msgpp           Pointer to pointer to next
+ *                              available message to process.
+ *                              If *msgpp == NULL, no more
+ *                              messages are available.
+ *
+ * @param[out]  get_outp        Pointer to an integer
+ *                              indicating how to respond
+ *                              if no more messages are
+ *                              available (msgpp). If integer
+ *                              is set to zero, loop_rec
+ *                              should jump to an appropriate
+ *                              wait instruction. If zero,
+ *                              the message queue lock remain
+ *                              locked since the test for
+ *                              more messages was done.
+ *                              If the integer is set to a
+ *                              value larger that zero, the
+ *                              process exited. If the integer
+ *                              is set to a value less than
+ *                              zero, the process is required
+ *                              to yield.
+ *
+ *
+ * @return                      The amount of reductions
+ *                              consumed.
+ *
+ */
+int
+erts_proc_sig_receive_helper(Process *c_p, int fcalls,
+                             int neg_o_reds, ErtsMessage **msgpp,
+                             int *get_outp);
+
+/**
+ *
+ * @brief Fetch signals from the outer queue
+ *
+ * Fetches signals from outer queue and places them in the
+ * middle queue ready for signal handling. If the middle
+ * queue is empty, only message signals were present in the
+ * outer queue, and no receive tracing has been enabled on
+ * the process, the middle queue is bypassed and messages
+ * are delivered directly to the inner queue instead.
+ *
+ * @param[in]   c_p             Pointer to process struct of
+ *                              currently executing process.
+ *
+ */
+void erts_proc_sig_fetch(Process *p);
+
+typedef struct {
+    Uint size;
+    ErtsMessage *msgp;
+} ErtsMessageInfo;
+
+/**
+ *
+ * @brief Prepare signal queue for inspection by process_info()
+ *
+ *
+ * @param[in]   c_p             Pointer to process struct of
+ *                              currently executing process.
+ *
+ * @param[in]   rp              Pointer to process struct of
+ *                              process to inspect.
+ *
+ * @param[in]   rp_locks        Process locks held on 'rp'.
+ *
+ * @param[in]   mip             Pointer to array of
+ *                              ErtsMessageInfo structures.
+ *                              
+ */
+
+Uint erts_proc_sig_prep_msgq_for_inspection(Process *c_p,
+                                            Process *rp,
+                                            ErtsProcLocks rp_locks,
+                                            ErtsMessageInfo *mip);
+
+
+/**
+ *
+ * @brief Move message data of messages in private queues to heap
+ *
+ * Move message data of messages in private queues to the heap.
+ * This is part of GC of processes that uses on-heap message
+ * data.
+ *
+ * @param[in]   c_p             Pointer to process struct of
+ *                              currently executing process.
+ *
+ */
+void erts_proc_sig_move_msgs_to_heap(Process *c_p);
+
+/**
+ *
+ * @brief Size of signal in bytes.
+ *
+ * @param[in]   sig             Signal to inspect.
+ *
+ */
+Uint erts_proc_sig_signal_size(ErtsSignal *sig);
+
+
+/**
+ *
+ * @brief Clear seq trace tokens on all signals
+ *
+ * Assumes thread progress has been blocked!
+ *
+ * @param[in]   c_p             Pointer to process
+ *
+ */
+void
+erts_proc_sig_clear_seq_trace_tokens(Process *c_p);
+
+/**
+ * @brief Initialize this functionality
+ */
+void erts_proc_sig_queue_init(void);
+
+void
+erts_proc_sig_debug_foreach_sig(Process *c_p,
+                                void (*msg_func)(ErtsMessage *, void *),
+                                void (*oh_func)(ErlOffHeap *, void *),
+                                void (*mon_func)(ErtsMonitor *, void *),
+                                void (*lnk_func)(ErtsLink *, void *),
+                                void *arg);
+
+extern Process *erts_dirty_process_signal_handler;
+extern Process *erts_dirty_process_signal_handler_high;
+extern Process *erts_dirty_process_signal_handler_max;
+
+#endif /* ERTS_PROC_SIG_QUEUE_H__ */
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 0d02d10ac9..7969025f57 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1996-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1996-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -53,6 +53,7 @@
 #include "erl_nfunc_sched.h"
 #include "erl_check_io.h"
 #include "erl_poll.h"
+#include "erl_proc_sig_queue.h"
 
 #define ERTS_CHECK_TIME_REDS CONTEXT_REDS
 #define ERTS_DELAYED_WAKEUP_INFINITY (~(Uint64) 0)
@@ -431,7 +432,8 @@ typedef enum {
     ERTS_PSTT_CLA,	/* Copy Literal Area */
     ERTS_PSTT_COHMQ,    /* Change off heap message queue */
     ERTS_PSTT_FTMQ,     /* Flush trace msg queue */
-    ERTS_PSTT_ETS_FREE_FIXATION
+    ERTS_PSTT_ETS_FREE_FIXATION,
+    ERTS_PSTT_PRIO_SIG  /* Elevate prio on signal management */
 } ErtsProcSysTaskType;
 
 #define ERTS_MAX_PROC_SYS_TASK_ARGS 2
@@ -579,7 +581,6 @@ dbg_chk_aux_work_val(erts_aint32_t value)
     valid |= ERTS_SSI_AUX_WORK_CNCLD_TMRS;
     valid |= ERTS_SSI_AUX_WORK_CNCLD_TMRS_THR_PRGR;
     valid |= ERTS_SSI_AUX_WORK_THR_PRGR_LATER_OP;
-    valid |= ERTS_SSI_AUX_WORK_PENDING_EXITERS;
 #if HAVE_ERTS_MSEG
     valid |= ERTS_SSI_AUX_WORK_MSEG_CACHE_CHECK;
 #endif
@@ -601,7 +602,6 @@ dbg_chk_aux_work_val(erts_aint32_t value)
 #define ERTS_DBG_CHK_SSI_AUX_WORK(SSI)
 #endif
 
-static void do_handle_pending_exiters(ErtsProcList *);
 static void wake_scheduler(ErtsRunQueue *rq);
 
 #if defined(ERTS_ENABLE_LOCK_CHECK)
@@ -666,8 +666,6 @@ erts_pre_init_process(void)
 	= "MISC_THR_PRGR";
     erts_aux_work_flag_descr[ERTS_SSI_AUX_WORK_MISC_IX]
 	= "MISC";
-    erts_aux_work_flag_descr[ERTS_SSI_AUX_WORK_PENDING_EXITERS_IX]
-	= "PENDING_EXITERS";
     erts_aux_work_flag_descr[ERTS_SSI_AUX_WORK_SET_TMO_IX]
 	= "SET_TMO";
     erts_aux_work_flag_descr[ERTS_SSI_AUX_WORK_MSEG_CACHE_CHECK_IX]
@@ -2531,27 +2529,6 @@ handle_mseg_cache_check(ErtsAuxWorkData *awdp, erts_aint32_t aux_work, int waiti
 
 
 static ERTS_INLINE erts_aint32_t
-handle_pending_exiters(ErtsAuxWorkData *awdp, erts_aint32_t aux_work, int waiting)
-{
-    ErtsProcList *pnd_xtrs;
-    ErtsRunQueue *rq;
-
-    rq = awdp->esdp->run_queue;
-    unset_aux_work_flags(awdp->ssi, ERTS_SSI_AUX_WORK_PENDING_EXITERS);
-
-    erts_runq_lock(rq);
-    pnd_xtrs = rq->procs.pending_exiters;
-    rq->procs.pending_exiters = NULL;
-    erts_runq_unlock(rq);
-
-    if (erts_proclist_fetch(&pnd_xtrs, NULL))
-	do_handle_pending_exiters(pnd_xtrs);
-
-    return aux_work & ~ERTS_SSI_AUX_WORK_PENDING_EXITERS;
-}
-
-
-static ERTS_INLINE erts_aint32_t
 handle_setup_aux_work_timer(ErtsAuxWorkData *awdp, erts_aint32_t aux_work, int waiting)
 {
     unset_aux_work_flags(awdp->ssi, ERTS_SSI_AUX_WORK_SET_TMO);
@@ -2632,9 +2609,6 @@ handle_aux_work(ErtsAuxWorkData *awdp, erts_aint32_t orig_aux_work, int waiting)
     HANDLE_AUX_WORK(ERTS_SSI_AUX_WORK_MISC,
 		    handle_misc_aux_work);
 
-    HANDLE_AUX_WORK(ERTS_SSI_AUX_WORK_PENDING_EXITERS,
-		    handle_pending_exiters);
-
     HANDLE_AUX_WORK(ERTS_SSI_AUX_WORK_SET_TMO,
 		    handle_setup_aux_work_timer);
 
@@ -5793,7 +5767,6 @@ erts_init_scheduling(int no_schedulers, int no_schedulers_online, int no_poll_th
 	rq->wakeup_other = 0;
 	rq->wakeup_other_reds = 0;
 
-	rq->procs.pending_exiters = NULL;
 	rq->procs.context_switches = 0;
 	rq->procs.reductions = 0;
 
@@ -6328,11 +6301,36 @@ schedule_out_process(ErtsRunQueue *c_rq, erts_aint32_t state, Process *p,
     int enqueue; /* < 0 -> use proxy */
     ErtsRunQueue* runq;
 
+    ASSERT(!(state & (ERTS_PSFLG_DIRTY_IO_PROC
+                      |ERTS_PSFLG_DIRTY_CPU_PROC))
+           || (BeamIsOpCode(*p->i, op_call_nif)
+               || BeamIsOpCode(*p->i, op_apply_bif)));
+
+    a = state;
+
+    /* Clear activ-sys if needed... */
+    while (1) {
+        n = e = a;
+        if (a & ERTS_PSFLG_ACTIVE_SYS) {
+            if (a & (ERTS_PSFLG_SIG_Q
+                     | ERTS_PSFLG_SIG_IN_Q
+                     | ERTS_PSFLG_SYS_TASKS))
+                break;
+            /* Clear active-sys */
+            n &= ~ERTS_PSFLG_ACTIVE_SYS;
+        }
+        a = erts_atomic32_cmpxchg_nob(&p->state, n, e);
+        if (a == e) {
+            a = n;
+            break;
+        }
+    }
+
     if (!is_normal_sched)
 	running_flgs = ERTS_PSFLG_DIRTY_RUNNING|ERTS_PSFLG_DIRTY_RUNNING_SYS;
     else {
 	running_flgs = ERTS_PSFLG_RUNNING|ERTS_PSFLG_RUNNING_SYS;
-        if (state & ERTS_PSFLG_DIRTY_ACTIVE_SYS
+        if ((a & ERTS_PSFLG_DIRTY_ACTIVE_SYS)
             && (p->flags & (F_DELAY_GC|F_DISABLE_GC))) {
             /*
              * Delay dirty GC; will be enabled automatically
@@ -6345,14 +6343,12 @@ schedule_out_process(ErtsRunQueue *c_rq, erts_aint32_t state, Process *p,
              */
             ASSERT(!(p->flags & (F_DIRTY_CLA | F_DIRTY_GC_HIBERNATE)));
 
-            state = erts_atomic32_read_band_nob(&p->state,
-                                                    ~ERTS_PSFLG_DIRTY_ACTIVE_SYS);
-            state &= ~ERTS_PSFLG_DIRTY_ACTIVE_SYS;
+            a = erts_atomic32_read_band_nob(&p->state,
+                                            ~ERTS_PSFLG_DIRTY_ACTIVE_SYS);
+            a &= ~ERTS_PSFLG_DIRTY_ACTIVE_SYS;
         }
     }
 
-    a = state;
-
     while (1) {
 	n = e = a;
 
@@ -6360,6 +6356,11 @@ schedule_out_process(ErtsRunQueue *c_rq, erts_aint32_t state, Process *p,
 
 	enqueue = ERTS_ENQUEUE_NOT;
 
+        ASSERT(((a & (ERTS_PSFLG_EXITING|ERTS_PSFLG_FREE))
+                != ERTS_PSFLG_EXITING)
+               || ((a & (ERTS_PSFLG_ACTIVE|ERTS_PSFLG_SUSPENDED))
+                   == ERTS_PSFLG_ACTIVE));
+
 	n &= ~running_flgs;
 	if ((a & (ERTS_PSFLG_ACTIVE_SYS|ERTS_PSFLG_DIRTY_ACTIVE_SYS))
 	    || (a & (ERTS_PSFLG_ACTIVE|ERTS_PSFLG_SUSPENDED)) == ERTS_PSFLG_ACTIVE) {
@@ -6584,7 +6585,7 @@ change_proc_schedule_state(Process *p,
     }
 
 
-    *statep = a;
+    *statep = n;
 
     return enqueue;
 }
@@ -6609,6 +6610,95 @@ erts_schedule_process(Process *p, erts_aint32_t state, ErtsProcLocks locks)
     schedule_process(p, state, locks);
 }
 
+static ERTS_INLINE erts_aint32_t
+active_sys_enqueue(Process *p, erts_aint32_t state,
+                   erts_aint32_t enable_flags, int status_locked)
+{
+    /*
+     * This function may or may not be called with status locke held.
+     * It always returns without the status lock held!
+     */
+    unsigned int prof_runnable_procs = erts_system_profile_flags.runnable_procs;
+    erts_aint32_t n, a = state, enq_prio = -1;
+    int slocked = status_locked;
+    int enqueue; /* < 0 -> use proxy */
+
+    /* Status lock prevents out of order "runnable proc" trace msgs */
+    ERTS_LC_ASSERT(slocked || !(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p)));
+    ERTS_LC_ASSERT(!slocked || (ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p)));
+
+    if (!prof_runnable_procs) {
+        if (slocked) {
+            erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
+            slocked = 0;
+        }
+    }
+    else {
+        if (!slocked) {
+            erts_proc_lock(p, ERTS_PROC_LOCK_STATUS);
+            slocked = !0;
+        }
+    }
+
+    ASSERT(!(state & ERTS_PSFLG_PROXY));
+
+    while (1) {
+	erts_aint32_t e;
+	n = e = a;
+
+	if (a & ERTS_PSFLG_FREE)
+	    goto cleanup; /* We don't want to schedule free processes... */
+
+	enqueue = ERTS_ENQUEUE_NOT;
+        n |= enable_flags;
+	n |= ERTS_PSFLG_ACTIVE_SYS;
+	if (!(a & (ERTS_PSFLG_RUNNING
+		   | ERTS_PSFLG_RUNNING_SYS
+		   | ERTS_PSFLG_DIRTY_RUNNING
+		   | ERTS_PSFLG_DIRTY_RUNNING_SYS)))
+	    enqueue = check_enqueue_in_prio_queue(p, &enq_prio, &n, a);
+	a = erts_atomic32_cmpxchg_mb(&p->state, n, e);
+	if (a == e)
+	    break;
+	if (a == n && enqueue == ERTS_ENQUEUE_NOT)
+	    goto cleanup;
+    }
+
+    if (prof_runnable_procs) {
+
+	if (!(a & (ERTS_PSFLG_ACTIVE_SYS
+		   | ERTS_PSFLG_RUNNING
+		   | ERTS_PSFLG_RUNNING_SYS
+		   | ERTS_PSFLG_DIRTY_RUNNING
+		   | ERTS_PSFLG_DIRTY_RUNNING_SYS))
+	    && (!(a & ERTS_PSFLG_ACTIVE) || (a & ERTS_PSFLG_SUSPENDED))) {
+	    /* We activated a prevously inactive process */
+	    profile_runnable_proc(p, am_active);
+	}
+
+	erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
+	slocked = 0;
+    }
+
+    add2runq(enqueue, enq_prio, p, n, NULL);
+
+cleanup:
+
+    if (slocked)
+	erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
+
+    ERTS_LC_ASSERT(!(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p)));
+
+    return n;
+}
+
+erts_aint32_t
+erts_proc_sys_schedule(Process *p, erts_aint32_t state, erts_aint32_t enable_flag)
+{
+    /* We are not allowed to call this function with status lock held... */
+    return active_sys_enqueue(p, state, enable_flag, 0);
+}
+
 static int
 schedule_process_sys_task(Process *p, erts_aint32_t prio, ErtsProcSysTask *st,
 			  erts_aint32_t *fail_state_p)
@@ -6616,19 +6706,16 @@ schedule_process_sys_task(Process *p, erts_aint32_t prio, ErtsProcSysTask *st,
     int res;
     int locked;
     ErtsProcSysTaskQs *stqs, *free_stqs;
-    erts_aint32_t fail_state, state, a, n, enq_prio;
-    int enqueue; /* < 0 -> use proxy */
-    unsigned int prof_runnable_procs;
+    erts_aint32_t fail_state, state;
 
     fail_state = *fail_state_p;
 
     res = 1; /* prepare for success */
     st->next = st->prev = st; /* Prep for empty prio queue */
     state = erts_atomic32_read_nob(&p->state);
-    prof_runnable_procs = erts_system_profile_flags.runnable_procs;
     locked = 0;
     free_stqs = NULL;
-    if (state & ERTS_PSFLG_ACTIVE_SYS)
+    if (state & ERTS_PSFLG_SYS_TASKS)
 	stqs = NULL;
     else {
     alloc_qs:
@@ -6648,6 +6735,7 @@ schedule_process_sys_task(Process *p, erts_aint32_t prio, ErtsProcSysTask *st,
 
 	state = erts_atomic32_read_nob(&p->state);
 	if (state & fail_state) {
+            erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
 	    *fail_state_p = (state & fail_state);
 	    free_stqs = stqs;
 	    res = 0;
@@ -6695,69 +6783,14 @@ schedule_process_sys_task(Process *p, erts_aint32_t prio, ErtsProcSysTask *st,
 	state = n;
     }
 
-
-    a = state;
-    enq_prio = -1;
-
-    /* Status lock prevents out of order "runnable proc" trace msgs */
-    ERTS_LC_ASSERT(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p));
-
-    if (!prof_runnable_procs) {
-	erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
-	locked = 0;
-    }
-
-    ASSERT(!(state & ERTS_PSFLG_PROXY));
-
-    while (1) {
-	erts_aint32_t e;
-	n = e = a;
-
-	if (a & ERTS_PSFLG_FREE)
-	    goto cleanup; /* We don't want to schedule free processes... */
-
-	enqueue = ERTS_ENQUEUE_NOT;
-	n |= ERTS_PSFLG_ACTIVE_SYS;
-	if (!(a & (ERTS_PSFLG_RUNNING
-		   | ERTS_PSFLG_RUNNING_SYS
-		   | ERTS_PSFLG_DIRTY_RUNNING
-		   | ERTS_PSFLG_DIRTY_RUNNING_SYS)))
-	    enqueue = check_enqueue_in_prio_queue(p, &enq_prio, &n, a);
-	a = erts_atomic32_cmpxchg_mb(&p->state, n, e);
-	if (a == e)
-	    break;
-	if (a == n && enqueue == ERTS_ENQUEUE_NOT)
-	    goto cleanup;
-    }
-
-    if (prof_runnable_procs) {
-
-	if (!(a & (ERTS_PSFLG_ACTIVE_SYS
-		   | ERTS_PSFLG_RUNNING
-		   | ERTS_PSFLG_RUNNING_SYS
-		   | ERTS_PSFLG_DIRTY_RUNNING
-		   | ERTS_PSFLG_DIRTY_RUNNING_SYS))
-	    && (!(a & ERTS_PSFLG_ACTIVE) || (a & ERTS_PSFLG_SUSPENDED))) {
-	    /* We activated a prevously inactive process */
-	    profile_runnable_proc(p, am_active);
-	}
-
-	erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
-	locked = 0;
-    }
-
-    add2runq(enqueue, enq_prio, p, n, NULL);
+    /* active_sys_enqueue() always return with status lock unlocked */
+    (void) active_sys_enqueue(p, state, ERTS_PSFLG_SYS_TASKS, locked);
 
 cleanup:
 
-    if (locked)
-	erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
-
     if (free_stqs)
 	proc_sys_task_queues_free(free_stqs);
 
-    ERTS_LC_ASSERT(!(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p)));
-
     return res;
 }
 
@@ -8536,11 +8569,13 @@ static ERTS_INLINE void
 cancel_suspend_of_suspendee(Process *p, ErtsProcLocks p_locks)
 {
     if (is_not_nil(p->suspendee)) {
+        ErtsMonitor *mon;
+        Eterm suspendee = p->suspendee;
 	Process *rp;
 	if (!(p_locks & ERTS_PROC_LOCK_STATUS))
 	    erts_proc_lock(p, ERTS_PROC_LOCK_STATUS);
 	rp = erts_pid2proc(p, p_locks|ERTS_PROC_LOCK_STATUS,
-			   p->suspendee, ERTS_PROC_LOCK_STATUS);
+			   suspendee, ERTS_PROC_LOCK_STATUS);
 	if (rp) {
 	    erts_resume(rp, ERTS_PROC_LOCK_STATUS);
 	    erts_proc_unlock(rp, ERTS_PROC_LOCK_STATUS);
@@ -8548,6 +8583,14 @@ cancel_suspend_of_suspendee(Process *p, ErtsProcLocks p_locks)
 	if (!(p_locks & ERTS_PROC_LOCK_STATUS))
 	    erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
 	p->suspendee = NIL;
+
+        mon = erts_monitor_tree_lookup(p->suspend_monitors,
+                                       suspendee);
+        if (mon) {
+            erts_monitor_tree_delete(&p->suspend_monitors,
+                                     mon);
+            erts_monitor_suspend_destroy(erts_monitor_suspend(mon));
+        }
     }
 }
 
@@ -8706,8 +8749,7 @@ pid2proc_not_running(Process *c_p, ErtsProcLocks c_p_locks,
 	    {
 		erts_aint32_t state;
 		state = erts_atomic32_read_nob(&rp->state);
-		ASSERT((state & ERTS_PSFLG_PENDING_EXIT)
-		       || !(state & ERTS_PSFLG_RUNNING));
+		ASSERT(!(state & ERTS_PSFLG_RUNNING));
 	    }
 #endif
 
@@ -8762,7 +8804,7 @@ erts_pid2proc_nropt(Process *c_p, ErtsProcLocks c_p_locks,
 
 static ERTS_INLINE int
 do_bif_suspend_process(Process *c_p,
-		       ErtsSuspendMonitor *smon,
+		       ErtsMonitorSuspend *smon,
 		       Process *suspendee)
 {
     ASSERT(suspendee);
@@ -8795,21 +8837,25 @@ handle_pend_bif_sync_suspend(Process *suspendee,
     suspender = erts_pid2proc(suspendee,
 			      suspendee_locks,
 			      suspender_pid,
-			      ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCK_STATUS);
+			      ERTS_PROC_LOCK_STATUS);
     if (suspender) {
+        ErtsMonitorSuspend *smon;
+        ErtsMonitor *mon;
+        mon = erts_monitor_tree_lookup(suspender->suspend_monitors,
+                                       suspendee->common.id);
+        smon = erts_monitor_suspend(mon);
+
 	ASSERT(is_nil(suspender->suspendee));
-	if (!suspendee_alive)
-	    erts_delete_suspend_monitor(&suspender->suspend_monitors,
-					suspendee->common.id);
+	if (!suspendee_alive) {
+            if (mon) {
+                erts_monitor_tree_delete(&suspender->suspend_monitors,
+                                         mon);
+                erts_monitor_suspend_destroy(smon);
+            }
+        }
 	else {
 #ifdef DEBUG
-	    int res;
-#endif
-	    ErtsSuspendMonitor *smon;
-	    smon = erts_lookup_suspend_monitor(suspender->suspend_monitors,
-					       suspendee->common.id);
-#ifdef DEBUG
-	    res =
+	    int res =
 #endif
 		do_bif_suspend_process(suspendee, smon, suspendee);
 	    ASSERT(!smon || res != 0);
@@ -8818,9 +8864,8 @@ handle_pend_bif_sync_suspend(Process *suspendee,
 	/* suspender is suspended waiting for suspendee to suspend;
 	   resume suspender */
 	ASSERT(suspender != suspendee);
-	resume_process(suspender, ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCK_STATUS);
-	erts_proc_unlock(suspender,
-			     ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCK_STATUS);
+	resume_process(suspender, ERTS_PROC_LOCK_STATUS);
+	erts_proc_unlock(suspender, ERTS_PROC_LOCK_STATUS);
     }
 }
 
@@ -8838,26 +8883,29 @@ handle_pend_bif_async_suspend(Process *suspendee,
     suspender = erts_pid2proc(suspendee,
 			      suspendee_locks,
 			      suspender_pid,
-			      ERTS_PROC_LOCK_LINK);
+			      ERTS_PROC_LOCK_STATUS);
     if (suspender) {
+        ErtsMonitorSuspend *smon;
+        ErtsMonitor *mon;
+        mon = erts_monitor_tree_lookup(suspender->suspend_monitors,
+                                       suspendee->common.id);
+        smon = erts_monitor_suspend(mon);
 	ASSERT(is_nil(suspender->suspendee));
-	if (!suspendee_alive)
-	    erts_delete_suspend_monitor(&suspender->suspend_monitors,
-					suspendee->common.id);
+	if (!suspendee_alive) {
+            if (mon) {
+                erts_monitor_tree_delete(&suspender->suspend_monitors,
+                                         mon);
+                erts_monitor_suspend_destroy(smon);
+            }
+        }
 	else {
 #ifdef DEBUG
-	    int res;
+	    int res =
 #endif
-	    ErtsSuspendMonitor *smon;
-	    smon = erts_lookup_suspend_monitor(suspender->suspend_monitors,
-					       suspendee->common.id);
-#ifdef DEBUG
-	    res =
-#endif
-	    do_bif_suspend_process(suspendee, smon, suspendee);
+                do_bif_suspend_process(suspendee, smon, suspendee);
 	    ASSERT(!smon || res != 0);
 	}
-	erts_proc_unlock(suspender, ERTS_PROC_LOCK_LINK);
+	erts_proc_unlock(suspender, ERTS_PROC_LOCK_STATUS);
     }
 }
 
@@ -8871,8 +8919,9 @@ suspend_process_2(BIF_ALIST_2)
 {
     Eterm res;
     Process* suspendee = NULL;
-    ErtsSuspendMonitor *smon;
+    ErtsMonitorSuspend *smon;
     ErtsProcLocks xlocks = (ErtsProcLocks) 0;
+    int created;
 
     /* Options and default values: */
     int asynchronous = 0;
@@ -8905,9 +8954,7 @@ suspend_process_2(BIF_ALIST_2)
 	    goto badarg;
     }
 
-    xlocks = ERTS_PROC_LOCK_LINK | (asynchronous
-				    ? (ErtsProcLocks) 0
-				    : ERTS_PROC_LOCK_STATUS);
+    xlocks = ERTS_PROC_LOCK_STATUS;
 
     erts_proc_lock(BIF_P, xlocks);
 
@@ -8918,15 +8965,14 @@ suspend_process_2(BIF_ALIST_2)
     if (!suspendee)
 	goto no_suspendee;
 
-    smon = erts_add_or_lookup_suspend_monitor(&BIF_P->suspend_monitors,
-					      BIF_ARG_1);
-
-    /* ... but a little trickier with SMP support ... */
+    smon = erts_monitor_suspend_tree_lookup_create(&BIF_P->suspend_monitors,
+                                                   &created,
+                                                   BIF_ARG_1);
 
     if (asynchronous) {
 	/* --- Asynchronous suspend begin ---------------------------------- */
 
-	ERTS_LC_ASSERT(ERTS_PROC_LOCK_LINK
+	ERTS_LC_ASSERT(ERTS_PROC_LOCK_STATUS
 			   & erts_proc_lc_my_proc_locks(BIF_P));
 	ERTS_LC_ASSERT(ERTS_PROC_LOCK_STATUS
 			   == erts_proc_lc_my_proc_locks(suspendee));
@@ -8968,9 +9014,9 @@ suspend_process_2(BIF_ALIST_2)
     else /* if (!asynchronous) */ {
 	/* --- Synchronous suspend begin ----------------------------------- */
 
-	ERTS_LC_ASSERT(((ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCK_STATUS)
+	ERTS_LC_ASSERT(((ERTS_PROC_LOCK_STATUS|ERTS_PROC_LOCK_STATUS)
 			    & erts_proc_lc_my_proc_locks(BIF_P))
-			   == (ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCK_STATUS));
+			   == (ERTS_PROC_LOCK_STATUS|ERTS_PROC_LOCK_STATUS));
 	ERTS_LC_ASSERT(ERTS_PROC_LOCK_STATUS
 			   == erts_proc_lc_my_proc_locks(suspendee));
 
@@ -9055,9 +9101,15 @@ suspend_process_2(BIF_ALIST_2)
     ERTS_BIF_PREP_ERROR(res, BIF_P, SYSTEM_LIMIT);
     goto do_return;
 
- no_suspendee:
-    BIF_P->suspendee = NIL;
-    erts_delete_suspend_monitor(&BIF_P->suspend_monitors, BIF_ARG_1);
+ no_suspendee: {
+        ErtsMonitor *mon;
+        BIF_P->suspendee = NIL;
+        mon = erts_monitor_tree_lookup(BIF_P->suspend_monitors, BIF_ARG_1);
+        if (mon) {
+            erts_monitor_tree_delete(&BIF_P->suspend_monitors, mon);
+            erts_monitor_suspend_destroy(erts_monitor_suspend(mon));
+        }
+    }
 
  badarg:
     ERTS_BIF_PREP_ERROR(res, BIF_P, BADARG);
@@ -9084,15 +9136,17 @@ suspend_process_2(BIF_ALIST_2)
 BIF_RETTYPE
 resume_process_1(BIF_ALIST_1)
 {
-    ErtsSuspendMonitor *smon;
+    ErtsMonitor *mon;
+    ErtsMonitorSuspend *smon;
     Process *suspendee;
     int is_active;
  
     if (BIF_P->common.id == BIF_ARG_1)
 	BIF_ERROR(BIF_P, BADARG);
 
-    erts_proc_lock(BIF_P, ERTS_PROC_LOCK_LINK);
-    smon = erts_lookup_suspend_monitor(BIF_P->suspend_monitors, BIF_ARG_1);
+    erts_proc_lock(BIF_P, ERTS_PROC_LOCK_STATUS);
+    mon = erts_monitor_tree_lookup(BIF_P->suspend_monitors, BIF_ARG_1);
+    smon = erts_monitor_suspend(mon);
 
     if (!smon) {
 	/* No previous suspend or dead suspendee */
@@ -9109,20 +9163,17 @@ resume_process_1(BIF_ALIST_1)
     }
     else if (smon->active) {
 	smon->active--;
-	ASSERT(smon->pending >= 0);
+	ASSERT(smon->pending == 0);
 	is_active = 1;
     }
     else {
 	/* No previous suspend or dead suspendee */
-	goto error;
+	goto no_suspendee;
     }
 
     if (smon->active || smon->pending || !is_active) {
 	/* Leave the suspendee as it is; just verify that it is still alive */
-	suspendee = erts_pid2proc(BIF_P,
-				  ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_LINK,
-				  BIF_ARG_1,
-				  0);
+	suspendee = erts_proc_lookup(BIF_ARG_1);
 	if (!suspendee)
 	    goto no_suspendee;
 
@@ -9130,11 +9181,18 @@ resume_process_1(BIF_ALIST_1)
     else {
 	/* Resume */
 	suspendee = erts_pid2proc(BIF_P,
-				  ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_LINK,
+				  ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_STATUS,
 				  BIF_ARG_1,
 				  ERTS_PROC_LOCK_STATUS);
-	if (!suspendee)
+	if (!suspendee) {
+            mon = erts_monitor_tree_lookup(BIF_P->suspend_monitors, BIF_ARG_1);
+            smon = erts_monitor_suspend(mon);
+            if (!mon)
+                goto error;
 	    goto no_suspendee;
+        }
+
+        ASSERT(mon == erts_monitor_tree_lookup(BIF_P->suspend_monitors, BIF_ARG_1));
 
 	ASSERT(ERTS_PSFLG_SUSPENDED
 	       & erts_atomic32_read_nob(&suspendee->state));
@@ -9144,19 +9202,24 @@ resume_process_1(BIF_ALIST_1)
 	erts_proc_unlock(suspendee, ERTS_PROC_LOCK_STATUS);
     }
 
-    if (!smon->active && !smon->pending)
-	erts_delete_suspend_monitor(&BIF_P->suspend_monitors, BIF_ARG_1);
+    if (!smon->active && !smon->pending) {
+        ASSERT(mon);
+        erts_monitor_tree_delete(&BIF_P->suspend_monitors, mon);
+        erts_monitor_suspend_destroy(smon);
+    }
 
-    erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_LINK);
+    erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_STATUS);
 
     BIF_RET(am_true);
 
  no_suspendee:
     /* cleanup */
-    erts_delete_suspend_monitor(&BIF_P->suspend_monitors, BIF_ARG_1);
+    ASSERT(mon);
+    erts_monitor_tree_delete(&BIF_P->suspend_monitors, mon);
+    erts_monitor_suspend_destroy(smon);
 
  error:
-    erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_LINK);
+    erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_STATUS);
     BIF_ERROR(BIF_P, BADARG);
 }
 
@@ -9375,9 +9438,8 @@ erts_resume_processes(ErtsProcList *list)
 }
 
 Eterm
-erts_get_process_priority(Process *p)
+erts_get_process_priority(erts_aint32_t state)
 {
-    erts_aint32_t state = erts_atomic32_read_nob(&p->state);
     switch (ERTS_PSFLGS_GET_USR_PRIO(state)) {
     case PRIORITY_MAX:		return am_max;
     case PRIORITY_HIGH:		return am_high;
@@ -9427,7 +9489,10 @@ erts_set_process_priority(Process *p, Eterm value)
 		}
 
 		max_qbit = 0;
-		if (a & ERTS_PSFLG_ACTIVE_SYS)
+                ASSERT((a & ERTS_PSFLG_SYS_TASKS)
+                       ? !!p->sys_task_qs
+                       : !p->sys_task_qs);
+		if (a & ERTS_PSFLG_SYS_TASKS)
 		    max_qbit |= p->sys_task_qs->qmask;
 		if (a & ERTS_PSFLG_DELAYED_SYS) {
 		    ErtsProcSysTaskQs *qs;
@@ -9450,8 +9515,8 @@ erts_set_process_priority(Process *p, Eterm value)
 		    aprio = PRIORITY_LOW;
 		    break;
 		default:
-		    ERTS_INTERNAL_ERROR("Invalid qmask");
-		    aprio = -1;
+                    aprio = nprio;
+                    break;
 		}
 
 		if (aprio > nprio) /* low value -> high prio */
@@ -9627,10 +9692,6 @@ Process *erts_schedule(ErtsSchedulerData *esdp, Process *p, int calls)
         /* have to re-read state after taking lock */
         state = erts_atomic32_read_nob(&p->state);
 
-	if (is_normal_sched && (state & ERTS_PSFLG_PENDING_EXIT))
-	    erts_handle_pending_exit(p, (ERTS_PROC_LOCK_MAIN
-					 | ERTS_PROC_LOCK_TRACE
-					 | ERTS_PROC_LOCK_STATUS));
 	if (p->pending_suspenders) 
 	    handle_pending_suspend(p, (ERTS_PROC_LOCK_MAIN
 				       | ERTS_PROC_LOCK_TRACE
@@ -9945,12 +10006,10 @@ Process *erts_schedule(ErtsSchedulerData *esdp, Process *p, int calls)
 			       & ((state & (ERTS_PSFLG_SUSPENDED
 					    | ERTS_PSFLG_EXITING
 					    | ERTS_PSFLG_FREE
-					    | ERTS_PSFLG_PENDING_EXIT
 					    | ERTS_PSFLG_ACTIVE_SYS
 					    | ERTS_PSFLG_DIRTY_ACTIVE_SYS))
 				  != ERTS_PSFLG_SUSPENDED)
-                               & (!(state & (ERTS_PSFLG_EXITING
-                                             | ERTS_PSFLG_PENDING_EXIT))
+                               & (!(state & ERTS_PSFLG_EXITING)
                                   | (!!is_normal_sched))
                     );
 
@@ -10042,7 +10101,6 @@ Process *erts_schedule(ErtsSchedulerData *esdp, Process *p, int calls)
 		goto sunlock_sched_out_proc;
             }
 	    if (state & (ERTS_PSFLG_ACTIVE_SYS
-			 | ERTS_PSFLG_PENDING_EXIT
 			 | ERTS_PSFLG_EXITING)) {
 		/*
 		 * IMPORTANT! We need to take care of
@@ -10065,13 +10123,6 @@ Process *erts_schedule(ErtsSchedulerData *esdp, Process *p, int calls)
 		      && (state & ERTS_PSFLG_DIRTY_IO_PROC)));	    
 	}
 
-	if (state & ERTS_PSFLG_PENDING_EXIT) {
-	    erts_handle_pending_exit(p,
-				     ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_STATUS);
-	    state = erts_atomic32_read_nob(&p->state);
-	}
-
-
 	erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
 
         /* Clear tracer if it has been removed */
@@ -10093,25 +10144,48 @@ Process *erts_schedule(ErtsSchedulerData *esdp, Process *p, int calls)
 	}
 
         if (is_normal_sched) {
-
             if (state & ERTS_PSFLG_RUNNING_SYS) {
-                /*
-                 * GC is normally never delayed when a process
-                 * is scheduled out, but might be when executing
-                 * hand written beam assembly in
-                 * prim_eval:'receive'. If GC is delayed we are
-                 * not allowed to execute system tasks.
-                 */
-                if (!(p->flags & F_DELAY_GC)) {
-                    int cost = execute_sys_tasks(p, &state, reds);
-                    calls += cost;
-                    reds -= cost;
-                    if (reds <= 0)
-                        goto sched_out_proc;
-                    if (state & ERTS_PSFLGS_DIRTY_WORK)
-                        goto sched_out_proc;
+                if (state & (ERTS_PSFLG_SIG_Q|ERTS_PSFLG_SIG_IN_Q)) {
+                    int local_only = !!(p->flags & F_LOCAL_SIGS_ONLY);
+                    if (!local_only || (state & ERTS_PSFLG_SIG_Q)) {
+                        int sig_reds;
+                        /*
+                         * If we have dirty work scheduled we allow
+                         * usage of all reductions since we need to
+                         * handle all signals before doing dirty
+                         * work...
+                         */
+                        if (state & ERTS_PSFLGS_DIRTY_WORK)
+                            sig_reds = reds;
+                        else
+                            sig_reds = ERTS_SIG_HANDLE_REDS_MAX_PREFERED;
+                        (void) erts_proc_sig_handle_incoming(p,
+                                                             &state,
+                                                             &sig_reds,
+                                                             sig_reds,
+                                                             local_only);
+                        reds -= sig_reds;
+                    }
+                }
+                if ((state & (ERTS_PSFLG_SYS_TASKS
+                              | ERTS_PSFLG_EXITING)) == ERTS_PSFLG_SYS_TASKS) {
+                    /*
+                     * GC is normally never delayed when a process
+                     * is scheduled out, but might be when executing
+                     * hand written beam assembly in
+                     * prim_eval:'receive'. If GC is delayed we are
+                     * not allowed to execute system tasks.
+                     */
+                    if (!(p->flags & F_DELAY_GC)) {
+                        int cost = execute_sys_tasks(p, &state, reds);
+                        calls += cost;
+                        reds -= cost;
+                    }
                 }
 
+                if (reds <= 0 || (state & ERTS_PSFLGS_DIRTY_WORK))
+                    goto sched_out_proc;
+
                 ASSERT(state & psflg_running_sys);
                 ASSERT(!(state & psflg_running));
 
@@ -10120,7 +10194,7 @@ Process *erts_schedule(ErtsSchedulerData *esdp, Process *p, int calls)
 
                     if (((state & (ERTS_PSFLG_SUSPENDED
                                    | ERTS_PSFLG_ACTIVE)) != ERTS_PSFLG_ACTIVE)
-                        && !(state & ERTS_PSFLG_EXITING)) {
+                        & !(state & ERTS_PSFLG_EXITING)) {
                         goto sched_out_proc;
                     }
 
@@ -10162,15 +10236,6 @@ Process *erts_schedule(ErtsSchedulerData *esdp, Process *p, int calls)
 	    
 	ERTS_CHK_HAVE_ONLY_MAIN_PROC_LOCK(p);
 
-	/* Never run a suspended process */
-#ifdef DEBUG
-        {
-            erts_aint32_t dstate = erts_atomic32_read_nob(&p->state);
-            ASSERT(!(ERTS_PSFLG_SUSPENDED & dstate)
-                   || (ERTS_PSFLG_DIRTY_RUNNING_SYS & dstate));
-        }
-#endif
-
 	ASSERT(erts_proc_read_refc(p) > 0);
 
 	if (!(state & ERTS_PSFLG_EXITING) && ERTS_PTMR_IS_TIMED_OUT(p)) {
@@ -10183,6 +10248,11 @@ Process *erts_schedule(ErtsSchedulerData *esdp, Process *p, int calls)
 	    ERTS_PTMR_CLEAR(p);
 	}
 
+        /* if exiting, we *shall* exit... */
+        ASSERT(!(state & ERTS_PSFLG_EXITING)
+               || p->i == (BeamInstr *) beam_exit
+               || p->i == (BeamInstr *) beam_continue_exit);
+
 #ifdef DEBUG
         if (is_normal_sched) {
 	    if (state & ERTS_PSFLGS_DIRTY_WORK)
@@ -10198,6 +10268,18 @@ Process *erts_schedule(ErtsSchedulerData *esdp, Process *p, int calls)
                     ERTS_INTERNAL_ERROR("Executing normal code on dirty UNKNOWN scheduler");
             }
         }
+        {
+            erts_aint32_t dstate = erts_atomic32_read_nob(&p->state);
+
+            /* Never run a suspended process */
+            ASSERT(!(ERTS_PSFLG_SUSPENDED & dstate)
+                   || (ERTS_PSFLG_DIRTY_RUNNING_SYS & dstate));
+
+            /* Do not execute on the wrong type of scheduler... */
+            ASSERT(is_normal_sched
+                   ? !(dstate & ERTS_PSFLGS_DIRTY_WORK)
+                   : !!(dstate & ERTS_PSFLGS_DIRTY_WORK));
+        }
 #endif
 
 	return p;
@@ -10399,7 +10481,7 @@ fetch_sys_task(Process *c_p, erts_aint32_t state, int *qmaskp, int *priop)
 	    n |= (prio << ERTS_PSFLGS_ACT_PRIO_OFFSET);
 
 	    if (!qmask)
-		n &= ~ERTS_PSFLG_ACTIVE_SYS;
+		n &= ~ERTS_PSFLG_SYS_TASKS;
 
 	    if (a == n)
 		break;
@@ -10439,12 +10521,8 @@ execute_sys_tasks(Process *c_p, erts_aint32_t *statep, int in_reds)
 	int st_prio;
 	Eterm st_res;
 
-	if (state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_PENDING_EXIT)) {
-	    if (state & ERTS_PSFLG_PENDING_EXIT)
-		erts_handle_pending_exit(c_p, ERTS_PROC_LOCK_MAIN);
-	    ASSERT(ERTS_PROC_IS_EXITING(c_p));
+	if (state & ERTS_PSFLG_EXITING)
 	    break;
-	}
 
 	st = fetch_sys_task(c_p, state, &qmask, &st_prio);
 	if (!st)
@@ -10540,6 +10618,70 @@ execute_sys_tasks(Process *c_p, erts_aint32_t *statep, int in_reds)
 	    reds -= erts_db_execute_free_fixation(c_p, (DbFixation*)st->arg[0]);
 	    st_res = am_true;
 	    break;
+        case ERTS_PSTT_PRIO_SIG: {
+            erts_aint32_t fail_state, state;
+            int local_only, sig_res, sig_reds = reds;
+	    st_res = am_false;
+
+            if (st->arg[0] == am_true)
+                local_only = !0;
+            else
+                local_only = 0;
+
+            sig_reds = reds;
+            sig_res = erts_proc_sig_handle_incoming(c_p, &state, &sig_reds,
+                                                    reds, local_only);
+            reds -= sig_reds;
+
+            if (state & ERTS_PSFLG_EXITING)
+                goto perm_elevate_prio;
+
+            if (sig_res)
+                break;
+
+            st->arg[0] = am_true;
+
+            fail_state = ERTS_PSFLG_EXITING;
+
+            if (schedule_process_sys_task(c_p, st_prio, st, &fail_state)) {
+                /* Successfully rescheduled task... */
+                st = NULL;
+            }
+            else {
+                erts_aint32_t a;
+
+                state = erts_atomic32_read_nob(&c_p->state);                         
+
+            perm_elevate_prio:
+
+                /*
+                 * we are about to terminate; permanently elevate
+                 * prio in order to ensure high prio signal
+                 * handling...
+                 */
+
+                a = state;
+                while (1) {
+                    erts_aint32_t aprio, uprio, n, e;
+                    ASSERT(!(a & ERTS_PSFLG_FREE));
+                    aprio = ERTS_PSFLGS_GET_ACT_PRIO(a);
+                    uprio = ERTS_PSFLGS_GET_USR_PRIO(a);
+                    if (aprio >= uprio)
+                        break; /* user prio >= actual prio */
+                    /*
+                     * actual prio is higher than user prio; raise
+                     * user prio to actual prio...
+                     */
+                    n = e = a;
+                    n &= ~ERTS_PSFLGS_USR_PRIO_MASK;
+                    n |= aprio << ERTS_PSFLGS_USR_PRIO_OFFSET;
+                    a = erts_atomic32_cmpxchg_mb(&c_p->state, n, e);
+                    if (a == e)
+                        break;
+                }
+            }
+            break;
+        }
 	default:
 	    ERTS_INTERNAL_ERROR("Invalid process sys task type");
 	    st_res = am_false;
@@ -10593,6 +10735,7 @@ cleanup_sys_tasks(Process *c_p, erts_aint32_t in_state, int in_reds)
 	case ERTS_PSTT_CPC:
         case ERTS_PSTT_COHMQ:
         case ERTS_PSTT_ETS_FREE_FIXATION:
+        case ERTS_PSTT_PRIO_SIG:
 	    st_res = am_false;
 	    break;
 	case ERTS_PSTT_CLA:
@@ -10645,8 +10788,8 @@ erts_execute_dirty_system_task(Process *c_p)
 
     if (c_p->flags & F_DIRTY_GC_HIBERNATE) {
 	erts_proc_lock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS);
-	ERTS_MSGQ_MV_INQ2PRIVQ(c_p);
-	if (c_p->msg.len)
+	erts_proc_sig_fetch(c_p);
+	if (c_p->sig_qs.len)
             c_p->flags &= ~F_DIRTY_GC_HIBERNATE; /* operation aborted... */
         else {
 	    erts_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS);
@@ -10718,7 +10861,7 @@ dispatch_system_task(Process *c_p, erts_aint_t fail_state,
 
     switch (st->type) {
     case ERTS_PSTT_CPC:
-	rp = erts_dirty_process_code_checker;
+	rp = erts_dirty_process_signal_handler;
 	ASSERT(fail_state & (ERTS_PSFLG_DIRTY_RUNNING
 			     | ERTS_PSFLG_DIRTY_RUNNING_SYS));
 	if (c_p == rp) {
@@ -10935,13 +11078,15 @@ erts_internal_request_system_task_4(BIF_ALIST_4)
 			       BIF_ARG_2, BIF_ARG_3, BIF_ARG_4);
 }
 
-static void
-erts_schedule_generic_sys_task(Eterm pid, ErtsProcSysTaskType type, void* arg)
+static int
+schedule_generic_sys_task(Eterm pid, ErtsProcSysTaskType type,
+                          int prio, Eterm arg0, Eterm arg1)
 {
-    Process *rp = erts_proc_lookup(pid);
+    int res = 0;
+    Process *rp = erts_proc_lookup_raw(pid);
     if (rp) {
 	ErtsProcSysTask *st;
-	erts_aint32_t state, fail_state;
+	erts_aint32_t st_prio, fail_state;
 
 	st = erts_alloc(ERTS_ALC_T_PROC_SYS_TSK,
 			ERTS_PROC_SYS_TASK_SIZE(0));
@@ -10950,31 +11095,46 @@ erts_schedule_generic_sys_task(Eterm pid, ErtsProcSysTaskType type, void* arg)
 	st->reply_tag = NIL;
 	st->req_id = NIL;
 	st->req_id_sz = 0;
-        st->arg[0] = (Eterm)arg;
+        st->arg[0] = arg0;
+        st->arg[1] = arg1;
 	ERTS_INIT_OFF_HEAP(&st->off_heap);
-	state = erts_atomic32_read_nob(&rp->state);
-
-	fail_state = ERTS_PSFLG_EXITING;
 
-	if (!schedule_process_sys_task(rp, ERTS_PSFLGS_GET_USR_PRIO(state),
-				       st, &fail_state))
+        if (prio >= 0) {
+            st_prio = (erts_aint32_t) prio;
+            fail_state = ERTS_PSFLG_FREE;
+        }
+        else {
+            erts_aint32_t state = erts_atomic32_read_nob(&rp->state);
+            st_prio = ERTS_PSFLGS_GET_USR_PRIO(state);
+            fail_state = ERTS_PSFLG_EXITING;
+        }
+        res = schedule_process_sys_task(rp, st_prio, st, &fail_state);
+	if (!res)
 	    erts_free(ERTS_ALC_T_PROC_SYS_TSK, st);
     }
+    return res;
 }
 
-
 void
 erts_schedule_complete_off_heap_message_queue_change(Eterm pid)
 {
-    erts_schedule_generic_sys_task(pid, ERTS_PSTT_COHMQ, NULL);
+    schedule_generic_sys_task(pid, ERTS_PSTT_COHMQ,
+                              -1, NIL, NIL);
 }
 
 void
 erts_schedule_ets_free_fixation(Eterm pid, DbFixation* fix)
 {
-    erts_schedule_generic_sys_task(pid, ERTS_PSTT_ETS_FREE_FIXATION, fix);
+    schedule_generic_sys_task(pid, ERTS_PSTT_ETS_FREE_FIXATION,
+                              -1, (Eterm) fix, NIL);
 }
 
+int
+erts_sig_prio(Eterm pid, int prio)
+{
+    return schedule_generic_sys_task(pid, ERTS_PSTT_PRIO_SIG,
+                                     prio, am_false, NIL);
+}
 
 static void
 flush_dirty_trace_messages(void *vpid)
@@ -11014,7 +11174,7 @@ erts_schedule_flush_trace_messages(Process *proc, int force_on_proc)
 
     dhndl = erts_thr_progress_unmanaged_delay();
 
-    erts_schedule_generic_sys_task(pid, ERTS_PSTT_FTMQ, NULL);
+    schedule_generic_sys_task(pid, ERTS_PSTT_FTMQ, -1, NIL, NIL);
 
     erts_thr_progress_unmanaged_continue(dhndl);
 
@@ -11210,9 +11370,11 @@ erts_set_gc_state(Process *c_p, int enable)
 #endif
 
 	    erts_atomic32_read_bset_nob(&c_p->state,
-					    (ERTS_PSFLG_DELAYED_SYS
-					     | ERTS_PSFLG_ACTIVE_SYS),
-					    ERTS_PSFLG_ACTIVE_SYS);
+                                        (ERTS_PSFLG_DELAYED_SYS
+                                         | ERTS_PSFLG_ACTIVE_SYS
+                                         | ERTS_PSFLG_SYS_TASKS),
+                                        (ERTS_PSFLG_ACTIVE_SYS
+                                         | ERTS_PSFLG_SYS_TASKS));
 
 #ifdef DEBUG
 	ASSERT(state & ERTS_PSFLG_DELAYED_SYS);
@@ -11675,7 +11837,7 @@ erl_create_process(Process* parent, /* Parent of process (default group leader).
     p->common.u.alive.reg = NULL;
     ERTS_P_LINKS(p) = NULL;
     ERTS_P_MONITORS(p) = NULL;
-    p->nodes_monitors = NULL;
+    ERTS_P_LT_MONITORS(p) = NULL;
     p->suspend_monitors = NULL;
 
     ASSERT(is_pid(parent->group_leader));
@@ -11692,14 +11854,20 @@ erl_create_process(Process* parent, /* Parent of process (default group leader).
 
     erts_get_default_proc_tracing(&ERTS_TRACE_FLAGS(p), &ERTS_TRACER(p));
 
-    p->msg.first = NULL;
-    p->msg.last = &p->msg.first;
-    p->msg.save = &p->msg.first;
-    p->msg.saved_last = &p->msg.first;
-    p->msg.len = 0;
-    p->msg_inq.first = NULL;
-    p->msg_inq.last = &p->msg_inq.first;
-    p->msg_inq.len = 0;
+    p->sig_qs.first = NULL;
+    p->sig_qs.last = &p->sig_qs.first;
+    p->sig_qs.cont = NULL;
+    p->sig_qs.cont_last = &p->sig_qs.cont;
+    p->sig_qs.save = &p->sig_qs.first;
+    p->sig_qs.saved_last = NULL;
+    p->sig_qs.len = 0;
+    p->sig_qs.nmsigs.next = NULL;
+    p->sig_qs.nmsigs.last = NULL;
+    p->sig_inq.first = NULL;
+    p->sig_inq.last = &p->sig_inq.first;
+    p->sig_inq.len = 0;
+    p->sig_inq.nmsigs.next = NULL;
+    p->sig_inq.nmsigs.last = NULL;
     p->bif_timers = NULL;
     p->mbuf = NULL;
     p->msg_frag = NULL;
@@ -11726,8 +11894,6 @@ erl_create_process(Process* parent, /* Parent of process (default group leader).
     p->scheduler_data = NULL;
     p->suspendee = NIL;
     p->pending_suspenders = NULL;
-    p->pending_exit.reason = THE_NON_VALUE;
-    p->pending_exit.bp = NULL;
 
 #if !defined(NO_FPE_SIGNALS) || defined(HIPE)
     p->fp_exception = 0;
@@ -11781,30 +11947,33 @@ erl_create_process(Process* parent, /* Parent of process (default group leader).
      */
 
     if (so->flags & SPO_LINK) {
-#ifdef DEBUG
-	int ret;
-#endif
-#ifdef DEBUG
-	ret = erts_add_link(&ERTS_P_LINKS(parent),  LINK_PID, p->common.id);
-	ASSERT(ret == 0);
-	ret = erts_add_link(&ERTS_P_LINKS(p), LINK_PID, parent->common.id);
-	ASSERT(ret == 0);
-#else	
-	erts_add_link(&ERTS_P_LINKS(parent), LINK_PID, p->common.id);
-	erts_add_link(&ERTS_P_LINKS(p), LINK_PID, parent->common.id);
-#endif
-
+        ErtsLink *lnk;
+        ErtsLinkData *ldp = erts_link_create(ERTS_LNK_TYPE_PROC,
+                                             parent->common.id,
+                                             p->common.id);
+        lnk = erts_link_tree_lookup_insert(&ERTS_P_LINKS(parent), &ldp->a);
+        if (lnk) {
+            /*
+             * This should more or less never happen, but could
+             * potentially happen if pid:s wrap...
+             */
+            erts_link_release(lnk);
+        }
+        erts_link_tree_insert(&ERTS_P_LINKS(p), &ldp->b);
     }
 
     /*
      * Test whether this process should be initially monitored by its parent.
      */
     if (so->flags & SPO_MONITOR) {
-	Eterm mref;
-
-	mref = erts_make_ref(parent);
-	erts_add_monitor(&ERTS_P_MONITORS(parent), MON_ORIGIN, mref, p->common.id, NIL);
-	erts_add_monitor(&ERTS_P_MONITORS(p), MON_TARGET, mref, parent->common.id, NIL);
+	Eterm mref = erts_make_ref(parent);
+        ErtsMonitorData *mdp = erts_monitor_create(ERTS_MON_TYPE_PROC,
+                                                   mref,
+                                                   parent->common.id,
+                                                   p->common.id,
+                                                   NIL);
+        erts_monitor_tree_insert(&ERTS_P_MONITORS(parent), &mdp->origin);
+        erts_monitor_list_insert(&ERTS_P_LT_MONITORS(p), &mdp->target);
 	so->mref = mref;
     }
 
@@ -11889,13 +12058,23 @@ void erts_init_empty_process(Process *p)
     p->mbuf_sz = 0;
     erts_atomic_init_nob(&p->psd, (erts_aint_t) NULL);
     ERTS_P_MONITORS(p) = NULL;
+    ERTS_P_LT_MONITORS(p) = NULL;
     ERTS_P_LINKS(p) = NULL;         /* List of links */
-    p->nodes_monitors = NULL;
     p->suspend_monitors = NULL;
-    p->msg.first = NULL;
-    p->msg.last = &p->msg.first;
-    p->msg.save = &p->msg.first;
-    p->msg.len = 0;
+    p->sig_qs.first = NULL;
+    p->sig_qs.last = &p->sig_qs.first;
+    p->sig_qs.cont = NULL;
+    p->sig_qs.cont_last = &p->sig_qs.cont;
+    p->sig_qs.save = &p->sig_qs.first;
+    p->sig_qs.saved_last = NULL;
+    p->sig_qs.len = 0;
+    p->sig_qs.nmsigs.next = NULL;
+    p->sig_qs.nmsigs.last = NULL;
+    p->sig_inq.first = NULL;
+    p->sig_inq.last = &p->sig_inq.first;
+    p->sig_inq.len = 0;
+    p->sig_inq.nmsigs.next = NULL;
+    p->sig_inq.nmsigs.last = NULL;
     p->bif_timers = NULL;
     p->dictionary = NULL;
     p->seq_trace_clock = 0;
@@ -11942,13 +12121,8 @@ void erts_init_empty_process(Process *p)
     erts_atomic32_init_nob(&p->state, (erts_aint32_t) PRIORITY_NORMAL);
 
     p->scheduler_data = NULL;
-    p->msg_inq.first = NULL;
-    p->msg_inq.last = &p->msg_inq.first;
-    p->msg_inq.len = 0;
     p->suspendee = NIL;
     p->pending_suspenders = NULL;
-    p->pending_exit.reason = THE_NON_VALUE;
-    p->pending_exit.bp = NULL;
     erts_proc_lock_init(p);
     erts_proc_unlock(p, ERTS_PROC_LOCKS_ALL);
     erts_init_runq_proc(p, ERTS_RUNQ_IX(0), 0);
@@ -11984,11 +12158,11 @@ erts_debug_verify_clean_empty_process(Process* p)
     ASSERT(p->old_heap == NULL);
 
     ASSERT(ERTS_P_MONITORS(p) == NULL);
+    ASSERT(ERTS_P_LT_MONITORS(p) == NULL);
     ASSERT(ERTS_P_LINKS(p) == NULL);
-    ASSERT(p->nodes_monitors == NULL);
     ASSERT(p->suspend_monitors == NULL);
-    ASSERT(p->msg.first == NULL);
-    ASSERT(p->msg.len == 0);
+    ASSERT(p->sig_qs.first == NULL);
+    ASSERT(p->sig_qs.len == 0);
     ASSERT(p->bif_timers == NULL);
     ASSERT(p->dictionary == NULL);
     ASSERT(p->catches == 0);
@@ -11998,12 +12172,10 @@ erts_debug_verify_clean_empty_process(Process* p)
 
     ASSERT(p->parent == NIL);
 
-    ASSERT(p->msg_inq.first == NULL);
-    ASSERT(p->msg_inq.len == 0);
+    ASSERT(p->sig_inq.first == NULL);
+    ASSERT(p->sig_inq.len == 0);
     ASSERT(p->suspendee == NIL);
     ASSERT(p->pending_suspenders == NULL);
-    ASSERT(p->pending_exit.reason == THE_NON_VALUE);
-    ASSERT(p->pending_exit.bp == NULL);
 
     /* Thing that erts_cleanup_empty_process() cleans up */
 
@@ -12104,817 +12276,330 @@ delete_process(Process* p)
     erts_erase_dicts(p);
 
     /* free all pending messages */
-    erts_cleanup_messages(p->msg.first);
-    p->msg.first = NULL;
+    erts_cleanup_messages(p->sig_qs.first);
+    p->sig_qs.first = NULL;
+    erts_cleanup_messages(p->sig_qs.cont);
+    p->sig_qs.cont = NULL;
 
-    ASSERT(!p->nodes_monitors);
     ASSERT(!p->suspend_monitors);
 
     p->fvalue = NIL;
 }
 
 static ERTS_INLINE void
-set_proc_exiting(Process *p,
-		 erts_aint32_t in_state,
-		 Eterm reason,
-		 ErlHeapFragment *bp)
+set_self_exiting(Process *c_p, Eterm reason, int *enqueue,
+                 erts_aint32_t *prio, erts_aint32_t *state)
 {
-    erts_aint32_t state = in_state, enq_prio = -1;
-    int enqueue;
-    ERTS_LC_ASSERT(erts_proc_lc_my_proc_locks(p) == ERTS_PROC_LOCKS_ALL);
-
-    enqueue = change_proc_schedule_state(p,
-					 (ERTS_PSFLG_SUSPENDED
-					  | ERTS_PSFLG_PENDING_EXIT
-					  | ERTS_PSFLGS_DIRTY_WORK),
-					 ERTS_PSFLG_EXITING|ERTS_PSFLG_ACTIVE,
-					 &state,
-					 &enq_prio,
-					 ERTS_PROC_LOCKS_ALL);
-
-    p->fvalue = reason;
-    if (bp)
-	erts_link_mbuf_to_proc(p, bp);
-    /*
-     * We used to set freason to EXC_EXIT here, but there is no need to
-     * save the stack trace since this process irreversibly is going to
-     * exit.
-     */
-    p->freason = EXTAG_EXIT;
-    KILL_CATCHES(p);
-    p->i = (BeamInstr *) beam_exit;
-
-
-    add2runq(enqueue, enq_prio, p, state, NULL);
-}
-
-static ERTS_INLINE erts_aint32_t
-set_proc_self_exiting(Process *c_p)
-{
-#ifdef DEBUG
-    int enqueue;
-#endif
-    erts_aint32_t state, enq_prio = -1;
+    erts_aint32_t st, enq_prio = -1;
+    int enq;
 
     ERTS_LC_ASSERT(erts_proc_lc_my_proc_locks(c_p) == ERTS_PROC_LOCKS_ALL);
 
-    state = erts_atomic32_read_nob(&c_p->state);
-    ASSERT(state & (ERTS_PSFLG_RUNNING
-		    |ERTS_PSFLG_RUNNING_SYS
-		    | ERTS_PSFLG_DIRTY_RUNNING
-		    | ERTS_PSFLG_DIRTY_RUNNING_SYS));
-
-#ifdef DEBUG
-    enqueue =
-#endif
-	change_proc_schedule_state(c_p,
-				   ERTS_PSFLG_SUSPENDED|ERTS_PSFLG_PENDING_EXIT,
-				   ERTS_PSFLG_EXITING|ERTS_PSFLG_ACTIVE,
-				   &state,
-				   &enq_prio,
-				   ERTS_PROC_LOCKS_ALL);
-
-    ASSERT(!enqueue);
-    return state;
-}
+    c_p->fvalue = reason;
 
+    st = erts_atomic32_read_nob(&c_p->state);
+    ASSERT(enqueue || (st & (ERTS_PSFLG_RUNNING
+                             |ERTS_PSFLG_RUNNING_SYS
+                             | ERTS_PSFLG_DIRTY_RUNNING
+                             | ERTS_PSFLG_DIRTY_RUNNING_SYS)));
 
-void
-erts_handle_pending_exit(Process *c_p, ErtsProcLocks locks)
-{
-    ErtsProcLocks xlocks;
-    ASSERT(is_value(c_p->pending_exit.reason));
-    ERTS_LC_ASSERT(erts_proc_lc_my_proc_locks(c_p) == locks);
-    ERTS_LC_ASSERT(locks & ERTS_PROC_LOCK_MAIN);
-    ERTS_LC_ASSERT(!((ERTS_PSFLG_EXITING|ERTS_PSFLG_FREE)
-			 & erts_atomic32_read_nob(&c_p->state)));
-
-    /* Ensure that all locks on c_p are locked before proceeding... */
-    if (locks == ERTS_PROC_LOCKS_ALL)
-	xlocks = 0;
-    else {
-	xlocks = ~locks & ERTS_PROC_LOCKS_ALL;
-	if (erts_proc_trylock(c_p, xlocks) == EBUSY) {
-	    erts_proc_unlock(c_p, locks & ~ERTS_PROC_LOCK_MAIN);
-	    erts_proc_lock(c_p, ERTS_PROC_LOCKS_ALL_MINOR);
-	}
-    }
+    enq = change_proc_schedule_state(c_p,
+                                     (ERTS_PSFLG_SUSPENDED
+                                      | ERTS_PSFLGS_DIRTY_WORK),
+                                     ERTS_PSFLG_EXITING|ERTS_PSFLG_ACTIVE,
+                                     &st,
+                                     &enq_prio,
+                                     ERTS_PROC_LOCKS_ALL);
 
-    set_proc_exiting(c_p,
-		     erts_atomic32_read_acqb(&c_p->state),
-		     c_p->pending_exit.reason,
-		     c_p->pending_exit.bp);
-    c_p->pending_exit.reason = THE_NON_VALUE;
-    c_p->pending_exit.bp = NULL;
-
-    if (xlocks)
-	erts_proc_unlock(c_p, xlocks);
+    ASSERT(enqueue || !enq);
+    if (enqueue)
+        *enqueue = enq;
+    if (prio)
+        *prio = enq_prio;
+    if (state)
+        *state = st;
 }
 
-static void save_pending_exiter(Process *p, ErtsProcList *plp);
-
-static void
-do_handle_pending_exiters(ErtsProcList *pnd_xtrs)
-{
-    /* 'list' is expected to have been fetched (i.e. not a ring anymore) */
-    ErtsProcList *plp = pnd_xtrs;
-
-    while (plp) {
-	ErtsProcList *next_plp = plp->next;
-	Process *p = erts_proc_lookup(plp->pid);
-	if (p) {
-	    erts_aint32_t state;
-	    /*
-	     * If the process is running on a normal scheduler, the
-	     * pending exit will soon be detected and handled by the
-	     * scheduler running the process (at schedule in/out).
-	     */
-	    if (erts_proc_trylock(p, ERTS_PROC_LOCKS_ALL) != EBUSY) {
-		if (erts_proclist_same(plp, p)) {
-		    state = erts_atomic32_read_acqb(&p->state);
-		    if (!(state & (ERTS_PSFLG_RUNNING
-				   | ERTS_PSFLG_RUNNING_SYS
-				   | ERTS_PSFLG_EXITING))) {
-			ASSERT(state & ERTS_PSFLG_PENDING_EXIT);
-			erts_handle_pending_exit(p, ERTS_PROC_LOCKS_ALL);
-		    }
-		}
-		erts_proc_unlock(p, ERTS_PROC_LOCKS_ALL);
-	    }
-	    else {
-		erts_proc_lock(p, ERTS_PROC_LOCK_STATUS);
-		if (erts_proclist_same(plp, p)) {
-		    state = erts_atomic32_read_acqb(&p->state);
-		    if (!(state & (ERTS_PSFLG_RUNNING
-				   | ERTS_PSFLG_RUNNING_SYS
-				   | ERTS_PSFLG_EXITING))) {
-			/*
-			 * Save process and try to acquire all
-			 * locks at a later time...
-			 */
-			save_pending_exiter(p, plp);
-			plp = NULL;
-		    }
-		}
-		erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
-	    }
-	}
-	if (plp)
-	    proclist_destroy(plp);
-	plp = next_plp;
-    }
-}
-
-static void
-save_pending_exiter(Process *p, ErtsProcList *plp)
+void
+erts_set_self_exiting(Process *c_p, Eterm reason)
 {
-    ErtsSchedulerSleepInfo *ssi;
-    ErtsRunQueue *rq;
-
-    ERTS_LC_ASSERT(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p));
-
-    rq = erts_get_runq_proc(p, NULL);
-    ASSERT(rq && !ERTS_RUNQ_IX_IS_DIRTY(rq->ix));
-
-    if (!plp)
-	plp = proclist_create(p);
-
-    erts_runq_lock(rq);
-
-    erts_proclist_store_last(&rq->procs.pending_exiters, plp);
-
-    non_empty_runq(rq);
-
-    ssi = rq->scheduler->ssi;
-
-    erts_runq_unlock(rq);
+    int enqueue;
+    erts_aint32_t enq_prio, state;
+    ERTS_LC_ASSERT(erts_proc_lc_my_proc_locks(c_p) == ERTS_PROC_LOCK_MAIN);
 
-    set_aux_work_flags_wakeup_nob(ssi, ERTS_SSI_AUX_WORK_PENDING_EXITERS);
-}
+    erts_proc_lock(c_p, ERTS_PROC_LOCKS_ALL_MINOR);
 
+    set_self_exiting(c_p, reason, &enqueue, &enq_prio, &state);
+    c_p->freason = EXTAG_EXIT;
+    KILL_CATCHES(c_p);
+    c_p->i = (BeamInstr *) beam_exit;
 
-/*
- * This function delivers an EXIT message to a process
- * which is trapping EXITs.
- */
+    /* Always active when exiting... */
+    ASSERT(state & ERTS_PSFLG_ACTIVE);
 
-static ERTS_INLINE void
-send_exit_message(Process *to, ErtsProcLocks *to_locksp,
-		  Eterm exit_term, Uint term_size, Eterm token)
-{
-    ErtsMessage *mp;
-    ErlOffHeap *ohp;
-    Eterm* hp;
-    Eterm mess;
-#ifdef SHCOPY_SEND
-    erts_shcopy_t info;
-#endif
+    /*
+     * If we are terminating a process that currently
+     * is executing on a dirty scheduler. It *should*
+     * be scheduled on a normal scheduler...
+     */
+    ASSERT(!(state & (ERTS_PSFLG_DIRTY_RUNNING
+                      | ERTS_PSFLG_DIRTY_RUNNING_SYS))
+           || enqueue == ERTS_ENQUEUE_NORMAL_QUEUE
+           || enqueue == -ERTS_ENQUEUE_NORMAL_QUEUE);
 
-    if (!have_seqtrace(token)) {
-#ifdef SHCOPY_SEND
-        INITIALIZE_SHCOPY(info);
-        term_size = copy_shared_calculate(exit_term, &info);
-	mp = erts_alloc_message_heap(to, to_locksp, term_size, &hp, &ohp);
-        mess = copy_shared_perform(exit_term, term_size, &info, &hp, ohp);
-        DESTROY_SHCOPY(info);
-#else
-	mp = erts_alloc_message_heap(to, to_locksp, term_size, &hp, &ohp);
-	mess = copy_struct(exit_term, term_size, &hp, ohp);
-#endif
-	erts_queue_message(to, *to_locksp, mp, mess, am_system);
-    } else {
-	Eterm temp_token;
-	Uint sz_token;
-
-	ASSERT(is_tuple(token));
-	sz_token = size_object(token);
-#ifdef SHCOPY_SEND
-        INITIALIZE_SHCOPY(info);
-        term_size = copy_shared_calculate(exit_term, &info);
-	mp = erts_alloc_message_heap(to, to_locksp, term_size+sz_token, &hp, &ohp);
-        mess = copy_shared_perform(exit_term, term_size, &info, &hp, ohp);
-        DESTROY_SHCOPY(info);
-#else
-	mp = erts_alloc_message_heap(to, to_locksp, term_size+sz_token, &hp, &ohp);
-	mess = copy_struct(exit_term, term_size, &hp, ohp);
-#endif
-	/* the trace token must in this case be updated by the caller */
-	seq_trace_output(token, mess, SEQ_TRACE_SEND, to->common.id, to);
-	temp_token = copy_struct(token, sz_token, &hp, ohp);
-        ERL_MESSAGE_TOKEN(mp) = temp_token;
-	erts_queue_message(to, *to_locksp, mp, mess, am_system);
-    }
+    erts_proc_unlock(c_p, ERTS_PROC_LOCKS_ALL_MINOR);
+    if (enqueue)
+        add2runq(enqueue, enq_prio, c_p, state, NULL);
 }
 
-/*
- *
- * *** Exit signal behavior ***
- *
- * Exit signals are asynchronous (truly asynchronous in the
- * SMP emulator). When the signal is received the receiver receives an
- * 'EXIT' message if it is trapping exits; otherwise, it will either
- * ignore the signal if the exit reason is normal, or go into an
- * exiting state (ERTS_PSFLG_EXITING). When a process has gone into the
- * exiting state it will not execute any more Erlang code, but it might
- * take a while before it actually exits. The exit signal is being
- * received when the 'EXIT' message is put in the message queue, the
- * signal is dropped, or when it changes state into exiting. The time it
- * is in the exiting state before actually exiting is undefined (it
- * might take a really long time under certain conditions). The
- * receiver of the exit signal does not break links or trigger monitors
- * until it actually exits.
- *
- * Exit signals and other signals, e.g. messages, have to be received
- * by a receiver in the same order as sent by a sender.
- *
- *
- *
- * Exit signal implementation in the SMP emulator:
- *
- * If the receiver is trapping exits, the signal is transformed
- * into an 'EXIT' message and sent as a normal message, if the
- * reason is normal the signal is dropped; otherwise, the process
- * is determined to be exited. The interesting case is when the
- * process is to be exited and this is what is described below.
- *
- * If it is possible, the receiver is set in the exiting state straight
- * away and we are done; otherwise, the sender places the exit reason
- * in the pending_exit field of the process struct and if necessary
- * adds the receiver to the run queue. It is typically not possible
- * to set a scheduled process or a process which we cannot get all locks
- * on without releasing locks on it in an exiting state straight away.
- *
- * The receiver will poll the pending_exit field when it reach certain
- * places during it's execution. When it discovers the pending exit
- * it will change state into the exiting state. If the receiver wasn't
- * scheduled when the pending exit was set, the first scheduler that
- * schedules a new process will set the receiving process in the exiting
- * state just before it schedules next process.
- * 
- * When the exit signal is placed in the pending_exit field, the signal
- * is considered as being in transit on the Erlang level. The signal is
- * actually in some kind of semi transit state, since we have already
- * determined how it should be received. It will exit the process no
- * matter what if it is received (the process may exit by itself before
- * reception of the exit signal). The signal is received when it is
- * discovered in the pending_exit field by the receiver.
- *
- * The receiver have to poll the pending_exit field at least before:
- * - moving messages from the message in queue to the private message
- *   queue. This in order to preserve signal order.
- * - unlink. Otherwise the process might get exited on a link that
- *   have been removed.
- * - changing the trap_exit flag to true. This in order to simplify the
- *   implementation; otherwise, we would have to transform the signal
- *   into an 'EXIT' message when setting the trap_exit flag to true. We
- *   would also have to maintain a queue of exit signals in transit.
- * - being scheduled in or out.
- */
-
-static ERTS_INLINE int
-send_exit_signal(Process *c_p,		/* current process if and only
-					   if reason is stored on it */
-		 Eterm from,		/* Id of sender of signal */
-		 Process *rp,		/* receiving process */
-		 ErtsProcLocks *rp_locks,/* current locks on receiver */
-		 Eterm reason,		/* exit reason */
-		 Eterm exit_tuple,	/* Prebuild exit tuple
-					   or THE_NON_VALUE */
-		 Uint exit_tuple_sz,	/* Size of prebuilt exit tuple
-					   (if exit_tuple != THE_NON_VALUE) */
-		 Eterm token,		/* token */
-		 Process *token_update, /* token updater */
-		 Uint32 flags		/* flags */
-    )		
-{
-    erts_aint32_t state = erts_atomic32_read_nob(&rp->state);
-    Eterm rsn = reason == am_kill ? am_killed : reason;
-
-    ERTS_LC_ASSERT(*rp_locks == erts_proc_lc_my_proc_locks(rp));
-    ERTS_LC_ASSERT((*rp_locks & ERTS_PROC_LOCKS_XSIG_SEND)
-		       == ERTS_PROC_LOCKS_XSIG_SEND);
-
-    ASSERT(reason != THE_NON_VALUE);
-
-#ifdef USE_VM_PROBES
-    if(DTRACE_ENABLED(process_exit_signal) && is_pid(from)) {
-        DTRACE_CHARBUF(sender_str, DTRACE_TERM_BUF_SIZE);
-        DTRACE_CHARBUF(receiver_str, DTRACE_TERM_BUF_SIZE);
-        DTRACE_CHARBUF(reason_buf, DTRACE_TERM_BUF_SIZE);
-
-        dtrace_pid_str(from, sender_str);
-        dtrace_proc_str(rp, receiver_str);
-        erts_snprintf(reason_buf, sizeof(DTRACE_CHARBUF_NAME(reason_buf)) - 1, "%T", reason);
-        DTRACE3(process_exit_signal, sender_str, receiver_str, reason_buf);
+void
+erts_proc_exit_handle_monitor(ErtsMonitor *mon, void *vctxt)
+{
+    Process *c_p = ((ErtsProcExitContext *) vctxt)->c_p;
+    Eterm reason = ((ErtsProcExitContext *) vctxt)->reason;
+    ErtsMonitorData *mdp = NULL;
+
+    if (erts_monitor_is_target(mon)) {
+        /* We are being watched... */
+        switch (mon->type) {
+        case ERTS_MON_TYPE_PROC:
+            erts_proc_sig_send_monitor_down(mon, reason);
+            mon = NULL;
+            break;
+        case ERTS_MON_TYPE_PORT: {
+	    Port *prt;
+            ASSERT(is_internal_port(mon->other.item));
+            prt = erts_id2port(mon->other.item);
+	    if (prt) {
+                erts_fire_port_monitor(prt, mon);
+                erts_port_release(prt);
+                mon = NULL;
+            }
+            break;
+        }
+        case ERTS_MON_TYPE_RESOURCE:
+            erts_fire_nif_monitor(mon);
+            mon = NULL;
+            break;
+        case ERTS_MON_TYPE_DIST_PROC: {
+            ErtsMonLnkDist *dist;
+            DistEntry *dep;
+            ErtsDSigData dsd;
+            int code;
+            Eterm watcher;
+            Eterm watched;
+
+            mdp = erts_monitor_to_data(mon);
+
+            if (mon->flags & ERTS_ML_FLG_NAME)
+                watched = ((ErtsMonitorDataExtended *) mdp)->u.name;
+            else
+                watched = c_p->common.id;
+            ASSERT(is_internal_pid(watched) || is_atom(watched));
+
+            watcher = mon->other.item;
+	    ASSERT(is_external_pid(watcher));    
+	    dep = external_pid_dist_entry(watcher);
+            ASSERT(dep);
+            dist = ((ErtsMonitorDataExtended *) mdp)->dist;
+            ASSERT(dist);
+            code = erts_dsig_prepare(&dsd, dep, NULL, 0,
+                                     ERTS_DSP_NO_LOCK, 0, 0);
+            switch (code) {
+            case ERTS_DSIG_PREP_CONNECTED:
+            case ERTS_DSIG_PREP_PENDING:
+                if (dist->connection_id == dsd.connection_id) {
+                    code = erts_dsig_send_m_exit(&dsd,
+                                                 watcher,
+                                                 watched,
+                                                 mdp->ref,
+                                                 reason);
+                    ASSERT(code == ERTS_DSIG_SEND_OK);
+                }
+            default:
+                break;
+            }
+            if (!erts_monitor_dist_delete(&mdp->origin))
+                mdp = NULL;
+            break;
+        }
+        default:
+            ERTS_INTERNAL_ERROR("Invalid target monitor type");
+            break;
+        }
     }
-#endif
-
-    if ((state & ERTS_PSFLG_TRAP_EXIT)
-	&& (reason != am_kill || (flags & ERTS_XSIG_FLG_IGN_KILL))) {
-        /* have to release the status and trace lock in order to send the exit message */
-        erts_proc_unlock(rp, *rp_locks & (ERTS_PROC_LOCKS_XSIG_SEND|ERTS_PROC_LOCK_TRACE));
-        *rp_locks &= ~(ERTS_PROC_LOCKS_XSIG_SEND|ERTS_PROC_LOCK_TRACE);
-        if (have_seqtrace(token) && token_update)
-	    seq_trace_update_send(token_update);
-	if (is_value(exit_tuple))
-	    send_exit_message(rp, rp_locks, exit_tuple, exit_tuple_sz, token);
-	else
-	    erts_deliver_exit_message(from, rp, rp_locks, rsn, token);
-	return 1; /* Receiver will get a message */
-    }
-    else if (reason != am_normal || (flags & ERTS_XSIG_FLG_NO_IGN_NORMAL)) {
-	if (!(state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_PENDING_EXIT))) {
-	    ASSERT(!rp->pending_exit.bp);
-
-	    if (rp == c_p && (*rp_locks & ERTS_PROC_LOCK_MAIN)) {
-		/* Ensure that all locks on c_p are locked before
-		   proceeding... */
-		if (*rp_locks != ERTS_PROC_LOCKS_ALL) {
-		    ErtsProcLocks need_locks = (~(*rp_locks)
-						& ERTS_PROC_LOCKS_ALL);
-		    if (erts_proc_trylock(c_p, need_locks) == EBUSY) {
-			erts_proc_unlock(c_p,
-					     *rp_locks & ~ERTS_PROC_LOCK_MAIN);
-			erts_proc_lock(c_p, ERTS_PROC_LOCKS_ALL_MINOR);
-		    }
-		    *rp_locks = ERTS_PROC_LOCKS_ALL;
-		}
-		set_proc_exiting(c_p, state, rsn, NULL);
-	    }
-	    else if (!(state & (ERTS_PSFLG_RUNNING
-                                | ERTS_PSFLG_RUNNING_SYS
-                                | ERTS_PSFLG_DIRTY_RUNNING_SYS))) {
-		/* Process not running ... */
-		ErtsProcLocks need_locks = ~(*rp_locks) & ERTS_PROC_LOCKS_ALL;
-		ErlHeapFragment *bp = NULL;
-		Eterm rsn_cpy;
-		if (need_locks
-		    && erts_proc_trylock(rp, need_locks) == EBUSY) {
-		    /* ... but we havn't got all locks on it ... */
-		    save_pending_exiter(rp, NULL); 
-		    /*
-		     * The pending exit will be discovered when next
-		     * process is scheduled in
-		     */
-                    goto set_pending_exit;
-		}
-                /* ...and we have all locks on it... */
-                *rp_locks = ERTS_PROC_LOCKS_ALL;
-
-		state = erts_atomic32_read_nob(&rp->state);
-
-		if (is_immed(rsn))
-		    rsn_cpy = rsn;
-		else {
-		    Eterm *hp;
-		    ErlOffHeap *ohp;
-		    Uint rsn_sz = size_object(rsn);
-		    if (state & ERTS_PSFLG_DIRTY_RUNNING) {
-			bp = new_message_buffer(rsn_sz);
-			ohp = &bp->off_heap;
-			hp = &bp->mem[0];
-		    }
-		    else
-		    {
-			hp = HAlloc(rp, rsn_sz);
-			ohp = &rp->off_heap;
-		    }
-		    rsn_cpy = copy_struct(rsn, rsn_sz, &hp, ohp);
-		}
-
-		set_proc_exiting(rp, state, rsn_cpy, bp);
-	    }
-	    else { /* Process running... */
- 
-		/*
-		 * The pending exit will be discovered when the process
-		 * is scheduled out if not discovered earlier.
-		 */
-
-	    set_pending_exit:
-		if (is_immed(rsn)) {
-		    rp->pending_exit.reason = rsn;
-		}
-		else {
-		    Eterm *hp;
-		    Uint sz = size_object(rsn);
-		    ErlHeapFragment *bp = new_message_buffer(sz);
-
-		    hp = &bp->mem[0];
-		    rp->pending_exit.reason = copy_struct(rsn,
-							  sz,
-							  &hp,
-							  &bp->off_heap);
-		    rp->pending_exit.bp = bp;
-		}
-
-		/*
-		 * If no dirty work has been scheduled, pending exit will
-                 * be discovered when the process is scheduled. If dirty work
-                 * has been scheduled, we may need to add it to a normal run
-                 * queue...
-		 */
-                {
-                    erts_aint32_t a = erts_atomic32_read_nob(&rp->state);
-                    while (1) {
-                        erts_aint32_t n, e;
-                        int dwork;
-                        n = e = a;
-                        n |= ERTS_PSFLG_PENDING_EXIT;
-                        dwork = !!(n & ERTS_PSFLGS_DIRTY_WORK);
-                        n &= ~ERTS_PSFLGS_DIRTY_WORK;
-                        a = erts_atomic32_cmpxchg_mb(&rp->state, n, e);
-                        if (a == e) {
-                            if (dwork)
-                                erts_schedule_process(rp, n, *rp_locks);
-                            break;
-                        }
-                    }
+    else { /* Origin monitor */
+        /* We are watching someone else... */
+        switch (mon->type) {
+        case ERTS_MON_TYPE_PROC:
+            erts_proc_sig_send_demonitor(mon);
+            mon = NULL;
+            break;
+        case ERTS_MON_TYPE_TIME_OFFSET:
+            erts_demonitor_time_offset(mon);
+            mon = NULL;
+            break;
+        case ERTS_MON_TYPE_NODE:
+            mdp = erts_monitor_to_data(mon);
+            if (!erts_monitor_dist_delete(&mdp->target))
+                mdp = NULL;
+            break;
+        case ERTS_MON_TYPE_NODES:
+            erts_monitor_nodes_delete(mon);
+            mon = NULL;
+            break;
+        case ERTS_MON_TYPE_PORT: {
+            Port *prt;
+            ASSERT(is_internal_port(mon->other.item));
+            prt = erts_port_lookup_raw(mon->other.item);
+            if (prt) {
+                erts_proc_lock(c_p, ERTS_PROC_LOCK_MAIN);
+                if (erts_port_demonitor(c_p, prt, mon) != ERTS_PORT_OP_DROPPED)
+                    mon = NULL;
+                erts_proc_unlock(c_p, ERTS_PROC_LOCK_MAIN);
+            }
+            break;
+        }
+        case ERTS_MON_TYPE_DIST_PROC: {
+            ErtsMonLnkDist *dist;
+            DistEntry *dep;
+            ErtsDSigData dsd;
+            int code;
+            Eterm watched;
+
+            mdp = erts_monitor_to_data(mon);
+            dist = ((ErtsMonitorDataExtended *) mdp)->dist;
+            ASSERT(dist);
+            if (mon->flags & ERTS_ML_FLG_NAME) {
+                watched = ((ErtsMonitorDataExtended *) mdp)->u.name;
+                ASSERT(is_atom(watched));
+                dep = erts_sysname_to_connected_dist_entry(dist->nodename);
+            }
+            else {
+                watched = mon->other.item;
+                ASSERT(is_external_pid(watched));
+		dep = external_pid_dist_entry(watched);
+            }
+            code = erts_dsig_prepare(&dsd, dep, NULL, 0,
+                                     ERTS_DSP_NO_LOCK, 0, 0);
+            switch (code) {
+            case ERTS_DSIG_PREP_CONNECTED:
+            case ERTS_DSIG_PREP_PENDING:
+                if (dist->connection_id == dsd.connection_id) {
+                    code = erts_dsig_send_demonitor(&dsd,
+                                                    c_p->common.id,
+                                                    watched,
+                                                    mdp->ref,
+                                                    1);
+                    ASSERT(code == ERTS_DSIG_SEND_OK);
                 }
-	    }
-	}
-	/* else:
-	 *
-	 *    The receiver already has a pending exit (or is exiting)
-	 *    so we drop this signal.
-	 *
-	 *    NOTE: dropping this exit signal is based on the assumption
-	 *          that the receiver *will* exit; either on the pending
-	 *          exit or by itself before seeing the pending exit.
-	 */
-	return -1; /* Receiver will exit */
+            default:
+                break;
+            }
+            if (!erts_monitor_dist_delete(&mdp->target))
+                mdp = NULL;
+            break;
+        }
+        default:
+            ERTS_INTERNAL_ERROR("Invalid origin monitor type");
+            break;
+        }
     }
 
-    return 0; /* Receiver unaffected */
+    if (mdp)
+        erts_monitor_release_both(mdp);
+    else if (mon)
+        erts_monitor_release(mon);
 }
 
-
-int
-erts_send_exit_signal(Process *c_p,
-		      Eterm from,
-		      Process *rp,
-		      ErtsProcLocks *rp_locks,
-		      Eterm reason,
-		      Eterm token,
-		      Process *token_update,
-		      Uint32 flags)
-{
-    return send_exit_signal(c_p,
-			    from,
-			    rp,
-			    rp_locks,
-			    reason,
-			    THE_NON_VALUE,
-			    0,
-			    token,
-			    token_update,
-			    flags);
-}
-
-typedef struct {
-    Eterm reason;
-    Process *p;
-} ExitMonitorContext;
-
-static void doit_exit_monitor(ErtsMonitor *mon, void *vpcontext)
-{
-    ExitMonitorContext *pcontext = vpcontext;
-    DistEntry *dep;
-    ErtsMonitor *rmon;
-
-    switch (mon->type) {
-    case MON_ORIGIN:
-	/* We are monitoring someone else, we need to demonitor that one.. */
-	if (is_atom(mon->u.pid)) { /* remote by name */
-	    ASSERT(is_node_name_atom(mon->u.pid));
-	    dep = erts_sysname_to_connected_dist_entry(mon->u.pid);
-	    if (dep) {
-		erts_de_links_lock(dep);
-		rmon = erts_remove_monitor(&(dep->monitors), mon->ref);
-		erts_de_links_unlock(dep);
-		if (rmon) {
-		    ErtsDSigData dsd;
-		    int code = erts_dsig_prepare(&dsd, dep, NULL, 0,
-						 ERTS_DSP_NO_LOCK, 0, 0);
-		    if (code == ERTS_DSIG_PREP_CONNECTED ||
-                        code == ERTS_DSIG_PREP_PENDING) {
-
-			code = erts_dsig_send_demonitor(&dsd,
-							rmon->u.pid,
-							mon->name,
-							mon->ref,
-							1);
-			ASSERT(code == ERTS_DSIG_SEND_OK);
-		    }
-		    erts_destroy_monitor(rmon);
-		}
-	    }
-	} else {
-            ASSERT(is_pid(mon->u.pid) || is_port(mon->u.pid));
-            /* if is local by pid or name */
-            if (is_internal_pid(mon->u.pid)) {
-                Process *rp = erts_pid2proc(NULL, 0, mon->u.pid, ERTS_PROC_LOCK_LINK);
-		if (!rp) {
-		    goto done;
-		}
-		rmon = erts_remove_monitor(&ERTS_P_MONITORS(rp), mon->ref);
-		erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-		if (rmon == NULL) {
-		    goto done;
-		}
-		erts_destroy_monitor(rmon);
-            } else if (is_internal_port(mon->u.pid)) {
-                /* Is a local port */
-                Port *prt = erts_port_lookup_raw(mon->u.pid);
-                if (!prt) {
-                    goto done;
-                }
-                erts_port_demonitor(pcontext->p,
-                                    ERTS_PORT_DEMONITOR_ORIGIN_ON_DEATHBED,
-                                    prt, mon->ref, NULL);
-            } else { /* remote by pid */
-		ASSERT(is_external_pid(mon->u.pid));
-		dep = external_pid_dist_entry(mon->u.pid);
-		ASSERT(dep != NULL);
-		if (dep) {
-		    erts_de_links_lock(dep);
-		    rmon = erts_remove_monitor(&(dep->monitors), mon->ref);
-		    erts_de_links_unlock(dep);
-		    if (rmon) {
-			ErtsDSigData dsd;
-			int code = erts_dsig_prepare(&dsd, dep, NULL, 0,
-						     ERTS_DSP_NO_LOCK, 0, 0);
-			if (code == ERTS_DSIG_PREP_CONNECTED ||
-                            code == ERTS_DSIG_PREP_PENDING) {
-
-			    code = erts_dsig_send_demonitor(&dsd,
-							    rmon->u.pid,
-							    mon->u.pid,
-							    mon->ref,
-							    1);
-			    ASSERT(code == ERTS_DSIG_SEND_OK);
-			}
-			erts_destroy_monitor(rmon);
-		    }
-		}
-	    }
-	}
-	break;
-    case MON_TARGET:
-	ASSERT(is_pid(mon->u.pid) || is_internal_port(mon->u.pid));
-	if (is_internal_port(mon->u.pid)) {
-	    Port *prt = erts_id2port(mon->u.pid);
-	    if (prt == NULL) {
-		goto done;
-	    }
-	    erts_fire_port_monitor(prt, mon->ref);
-	    erts_port_release(prt); 
-	} else if (is_internal_pid(mon->u.pid)) {/* local by name or pid */
-	    Eterm watched;
-            Process *rp;
-	    DeclareTmpHeapNoproc(lhp,3);
-	    ErtsProcLocks rp_locks = (ERTS_PROC_LOCK_LINK
-				      | ERTS_PROC_LOCKS_MSG_SEND);
-	    rp = erts_pid2proc(NULL, 0, mon->u.pid, rp_locks);
-	    if (rp == NULL) {
-		goto done;
-	    }
-	    UseTmpHeapNoproc(3);
-	    rmon = erts_remove_monitor(&ERTS_P_MONITORS(rp), mon->ref);
-	    if (rmon) {
-		erts_destroy_monitor(rmon);
-		watched = (is_atom(mon->name)
-			   ? TUPLE2(lhp, mon->name, 
-				    erts_this_dist_entry->sysname)
-			   : pcontext->p->common.id);
-		erts_queue_monitor_message(rp, &rp_locks, mon->ref, am_process, 
-					   watched, pcontext->reason);
-	    }
-	    UnUseTmpHeapNoproc(3);
-	    /* else: demonitor while we exited, i.e. do nothing... */
-	    erts_proc_unlock(rp, rp_locks);
-	} else { /* external by pid or name */
-	    ASSERT(is_external_pid(mon->u.pid));    
-	    dep = external_pid_dist_entry(mon->u.pid);
-	    ASSERT(dep != NULL);
-	    if (dep) {
-		erts_de_links_lock(dep);
-		rmon = erts_remove_monitor(&(dep->monitors), mon->ref);
-		erts_de_links_unlock(dep);
-		if (rmon) {
-		    ErtsDSigData dsd;
-		    int code = erts_dsig_prepare(&dsd, dep, NULL, 0,
-						 ERTS_DSP_NO_LOCK, 0, 0);
-		    if (code == ERTS_DSIG_PREP_CONNECTED) {
-			code = erts_dsig_send_m_exit(&dsd,
-						     mon->u.pid,
-						     (rmon->name != NIL
-						      ? rmon->name
-						      : rmon->u.pid),
-						     mon->ref,
-						     pcontext->reason);
-			ASSERT(code == ERTS_DSIG_SEND_OK);
-		    }
-		    erts_destroy_monitor(rmon);
-		}
-	    }
-	}
-	break;
-    case MON_NIF_TARGET:
-        erts_fire_nif_monitor(mon->u.resource,
-                              pcontext->p->common.id,
-                              mon->ref);
+void
+erts_proc_exit_handle_link(ErtsLink *lnk, void *vctxt)
+{
+    Process *c_p = ((ErtsProcExitContext *) vctxt)->c_p;
+    Eterm reason = ((ErtsProcExitContext *) vctxt)->reason;
+    ErtsLinkData *ldp = NULL;
+
+    switch (lnk->type) {
+    case ERTS_LNK_TYPE_PROC:
+        ASSERT(is_internal_pid(lnk->other.item));
+        erts_proc_sig_send_link_exit(c_p, c_p->common.id, lnk,
+                                     reason, SEQ_TRACE_TOKEN(c_p));
+        lnk = NULL;
+        break;
+    case ERTS_LNK_TYPE_PORT: {
+        Port *prt;
+        ASSERT(is_internal_port(lnk->other.item));
+        prt = erts_port_lookup(lnk->other.item,
+                               ERTS_PORT_SFLGS_INVALID_LOOKUP);
+        if (prt)
+            erts_port_exit(NULL,
+                           (ERTS_PORT_SIG_FLG_FORCE_SCHED
+                            | ERTS_PORT_SIG_FLG_BROKEN_LINK),
+                           prt,
+                           c_p->common.id,
+                           reason,
+                           NULL);
+        break;
+    }
+    case ERTS_LNK_TYPE_DIST_PROC: {
+        DistEntry *dep;
+        ErtsMonLnkDist *dist;
+        ErtsLink *dlnk;
+        ErtsDSigData dsd;
+        int code;
+
+        dlnk = erts_link_to_other(lnk, &ldp);
+        dist = ((ErtsLinkDataExtended *) ldp)->dist;
+
+        ASSERT(is_external_pid(lnk->other.item));
+        dep = external_pid_dist_entry(lnk->other.item);
+
+        ASSERT(dep != erts_this_dist_entry);
+
+        if (!erts_link_dist_delete(dlnk))
+            ldp = NULL;
+
+        erts_proc_lock(c_p, ERTS_PROC_LOCK_MAIN);
+        code = erts_dsig_prepare(&dsd, dep, c_p, 0, ERTS_DSP_NO_LOCK, 0, 0);
+        switch (code) {
+        case ERTS_DSIG_PREP_CONNECTED:
+        case ERTS_DSIG_PREP_PENDING:
+            if (dist->connection_id == dsd.connection_id) {
+                code = erts_dsig_send_exit_tt(&dsd,
+                                              c_p->common.id,
+                                              lnk->other.item,
+                                              reason,
+                                              SEQ_TRACE_TOKEN(c_p));
+                ASSERT(code == ERTS_DSIG_SEND_OK);
+            }
+        }
+        erts_proc_unlock(c_p, ERTS_PROC_LOCK_MAIN);
         break;
-    case MON_TIME_OFFSET:
-	erts_demonitor_time_offset(mon->ref);
-	break;
-    default:
-	ERTS_INTERNAL_ERROR("Invalid monitor type");
     }
- done:
-    /* As the monitors are previously removed from the process, 
-       distribution operations will not cause monitors to disappear,
-       we can safely delete it. */
-       
-    erts_destroy_monitor(mon);
-}
-
-typedef struct {
-    Process *p;
-    Eterm reason;
-    Eterm exit_tuple;
-    Uint exit_tuple_sz;
-} ExitLinkContext;
-
-static void doit_exit_link(ErtsLink *lnk, void *vpcontext)
-{
-    ExitLinkContext *pcontext = vpcontext;
-    /* Unpack context, it's readonly */
-    Process *p = pcontext->p;
-    Eterm reason = pcontext->reason;
-    Eterm exit_tuple = pcontext->exit_tuple;
-    Uint exit_tuple_sz = pcontext->exit_tuple_sz;
-    Eterm item = lnk->pid;
-    ErtsLink *rlnk;
-    DistEntry *dep;
-    Process *rp;
-
-
-    switch(lnk->type) {
-    case LINK_PID:
-	if(is_internal_port(item)) {
-	    Port *prt = erts_port_lookup(item, ERTS_PORT_SFLGS_INVALID_LOOKUP);
-	    if (prt)
-		erts_port_exit(NULL,
-			       (ERTS_PORT_SIG_FLG_FORCE_SCHED
-				| ERTS_PORT_SIG_FLG_BROKEN_LINK),
-			       prt,
-			       p->common.id,
-			       reason,
-			       NULL);
-	}
-	else if(is_external_port(item)) {
-	    erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
-	    erts_dsprintf(dsbufp,
-			  "Erroneous link between %T and external port %T "
-			  "found\n",
-			  p->common.id,
-			  item);
-	    erts_send_error_to_logger_nogl(dsbufp);
-	    ASSERT(0); /* It isn't possible to setup such a link... */
-	}
-	else if (is_internal_pid(item)) {
-	    ErtsProcLocks rp_locks = (ERTS_PROC_LOCK_LINK
-				      | ERTS_PROC_LOCKS_XSIG_SEND);
-	    rp = erts_pid2proc(NULL, 0, item, rp_locks);
-	    if (rp) {
-		rlnk = erts_remove_link(&ERTS_P_LINKS(rp), p->common.id);
-		/* If rlnk == NULL, we got unlinked while exiting,
-		   i.e., do nothing... */
-		if (rlnk) {
-		    int xres;
-		    erts_destroy_link(rlnk);
-		    xres = send_exit_signal(NULL,
-					    p->common.id,
-					    rp,
-					    &rp_locks, 
-					    reason,
-					    exit_tuple,
-					    exit_tuple_sz,
-					    SEQ_TRACE_TOKEN(p),
-					    p,
-					    ERTS_XSIG_FLG_IGN_KILL);
-		    if (xres >= 0 && IS_TRACED_FL(rp, F_TRACE_PROCS)) {
-			/* We didn't exit the process and it is traced */
-			if (IS_TRACED_FL(rp, F_TRACE_PROCS)) {
-                            if (rp_locks & ERTS_PROC_LOCKS_XSIG_SEND) {
-                                erts_proc_unlock(rp, ERTS_PROC_LOCKS_XSIG_SEND);
-                                rp_locks &= ~ERTS_PROC_LOCKS_XSIG_SEND;
-                            }
-			    trace_proc(NULL, 0, rp, am_getting_unlinked, p->common.id);
-			}
-		    }
-		}
-		ASSERT(rp != p);
-		erts_proc_unlock(rp, rp_locks);
-	    }
-	}
-	else if (is_external_pid(item)) {
-	    dep = external_pid_dist_entry(item);
-	    if(dep != erts_this_dist_entry) {
-		ErtsDSigData dsd;
-		int code;
-		ErtsDistLinkData dld;
-		erts_remove_dist_link(&dld, p->common.id, item, dep);
-                if (dld.d_lnk) {
-                    erts_proc_lock(p, ERTS_PROC_LOCK_MAIN);
-                    code = erts_dsig_prepare(&dsd, dep, p, 0, ERTS_DSP_NO_LOCK, 0, 0);
-                    if (code == ERTS_DSIG_PREP_CONNECTED ||
-                        code == ERTS_DSIG_PREP_PENDING) {
-
-                        code = erts_dsig_send_exit_tt(&dsd, p->common.id, item,
-                                                      reason, SEQ_TRACE_TOKEN(p));
-                        ASSERT(code == ERTS_DSIG_SEND_OK);
-                    }
-                    erts_proc_unlock(p, ERTS_PROC_LOCK_MAIN);
-                }
-		erts_destroy_dist_link(&dld);
-	    }
-	}
-	break;
-    case LINK_NODE:
-	ASSERT(is_node_name_atom(item));
-	dep = erts_sysname_to_connected_dist_entry(item);
-	if(dep) {
-	    /* dist entries have node links in a separate structure to 
-	       avoid confusion */
-	    erts_de_links_lock(dep);
-	    rlnk = erts_remove_link(&(dep->node_links), p->common.id);
-	    erts_de_links_unlock(dep);
-	    if (rlnk)
-		erts_destroy_link(rlnk);
-	}
-	break;
-	
     default:
-	erts_exit(ERTS_ERROR_EXIT, "bad type in link list\n");
-	break;
+        ERTS_INTERNAL_ERROR("Unexpected link type");
+        break;
     }
-    erts_destroy_link(lnk);
+
+    if (ldp)
+        erts_link_release_both(ldp);
+    else if (lnk)
+        erts_link_release(lnk);
 }
 
 static void
-resume_suspend_monitor(ErtsSuspendMonitor *smon, void *vc_p)
+resume_suspend_monitor(ErtsMonitor *mon, void *vc_p)
 {
+    ErtsMonitorSuspend *smon = erts_monitor_suspend(mon);
     Process *suspendee = erts_pid2proc((Process *) vc_p, ERTS_PROC_LOCK_MAIN,
-				       smon->pid, ERTS_PROC_LOCK_STATUS);
+				       smon->mon.other.item, ERTS_PROC_LOCK_STATUS);
     if (suspendee) {
 	ASSERT(suspendee != vc_p);
 	if (smon->active)
 	    resume_process(suspendee, ERTS_PROC_LOCK_STATUS);
 	erts_proc_unlock(suspendee, ERTS_PROC_LOCK_STATUS);
     }
-    erts_destroy_suspend_monitor(smon);
+    erts_monitor_suspend_destroy(smon);
 }
 
 /* this function fishishes a process and propagates exit messages - called
@@ -12923,8 +12608,6 @@ void
 erts_do_exit_process(Process* p, Eterm reason)
 {
     p->arity = 0;		/* No live registers */
-    p->fvalue = reason;
-    
 
 #ifdef USE_VM_PROBES
     if (DTRACE_ENABLED(process_exit)) {
@@ -12948,18 +12631,11 @@ erts_do_exit_process(Process* p, Eterm reason)
        process from exiting until the lock has been released. */
     erts_proc_lock(p, ERTS_PROC_LOCKS_ALL_MINOR);
 
-    if (ERTS_PSFLG_PENDING_EXIT & set_proc_self_exiting(p)) {
-	/* Process exited before pending exit was received... */
-	p->pending_exit.reason = THE_NON_VALUE;
-	if (p->pending_exit.bp) {
-	    free_message_buffer(p->pending_exit.bp);
-	    p->pending_exit.bp = NULL;
-	}
-    }
+    set_self_exiting(p, reason, NULL, NULL, NULL);
 
     cancel_suspend_of_suspendee(p, ERTS_PROC_LOCKS_ALL); 
 
-    ERTS_MSGQ_MV_INQ2PRIVQ(p);
+    erts_proc_sig_fetch(p);
 
     if (IS_TRACED(p)) {
 	if (IS_TRACED_FL(p, F_TRACE_CALLS))
@@ -12996,13 +12672,15 @@ erts_do_exit_process(Process* p, Eterm reason)
 void
 erts_continue_exit_process(Process *p)
 {
-    ErtsLink* lnk;
-    ErtsMonitor *mon;
+    ErtsLink *links;
+    ErtsMonitor *monitors;
+    ErtsMonitor *lt_monitors;
     ErtsProcLocks curr_locks = ERTS_PROC_LOCK_MAIN;
     Eterm reason = p->fvalue;
     DistEntry *dep = NULL;
     erts_aint32_t state;
     int delay_del_proc = 0;
+    ErtsProcExitContext pectxt;
 
 #ifdef DEBUG
     int yield_allowed = 1;
@@ -13074,7 +12752,7 @@ erts_continue_exit_process(Process *p)
 
     erts_set_gc_state(p, 1);
     state = erts_atomic32_read_acqb(&p->state);
-    if (state & ERTS_PSFLG_ACTIVE_SYS
+    if ((state & ERTS_PSFLG_SYS_TASKS)
         || p->dirty_sys_tasks
         ) {
 	if (cleanup_sys_tasks(p, state, CONTEXT_REDS) >= CONTEXT_REDS/2)
@@ -13094,18 +12772,10 @@ erts_continue_exit_process(Process *p)
 	p->flags &= ~F_USING_DDLL;
     }
 
-    if (p->nodes_monitors) {
-	erts_delete_nodes_monitors(p, ERTS_PROC_LOCK_MAIN);
-	p->nodes_monitors = NULL;
-    }
-	
-
-    if (p->suspend_monitors) {
-	erts_sweep_suspend_monitors(p->suspend_monitors,
-				    resume_suspend_monitor,
-				    p);
-	p->suspend_monitors = NULL;
-    }
+    if (p->suspend_monitors)
+        erts_monitor_tree_foreach_delete(&p->suspend_monitors,
+                                         resume_suspend_monitor,
+                                         p);
 
     /*
      * The registered name *should* be the last "erlang resource" to
@@ -13134,8 +12804,9 @@ erts_continue_exit_process(Process *p)
      * Note! The monitor and link fields will be overwritten 
      * by erts_ptab_delete_element() below.
      */
-    mon = ERTS_P_MONITORS(p);
-    lnk = ERTS_P_LINKS(p);
+    links = ERTS_P_LINKS(p);
+    monitors = ERTS_P_MONITORS(p);
+    lt_monitors = ERTS_P_LT_MONITORS(p);
 
     {
 	/* Do *not* use erts_get_runq_proc() */
@@ -13172,7 +12843,9 @@ erts_continue_exit_process(Process *p)
 	    n = e = a;
 	    ASSERT(a & ERTS_PSFLG_EXITING);
 	    n |= ERTS_PSFLG_FREE;
-	    n &= ~ERTS_PSFLG_ACTIVE;
+	    n &= ~(ERTS_PSFLG_ACTIVE
+                   | ERTS_PSFLG_ACTIVE_SYS
+                   | ERTS_PSFLG_DIRTY_ACTIVE_SYS);
 	    if ((n & ERTS_PSFLG_IN_RUNQ) && !refc_inced) {
 		erts_proc_inc_refc(p);
 		refc_inced = 1;
@@ -13207,33 +12880,40 @@ erts_continue_exit_process(Process *p)
         erts_deref_dist_entry(dep);
     }
 
-    /*
-     * Pre-build the EXIT tuple if there are any links.
-     */
-    if (lnk) {
-	DeclareTmpHeap(tmp_heap,4,p);
-	Eterm exit_tuple;
-	Uint exit_tuple_sz;
-	Eterm* hp;
-
-	UseTmpHeap(4,p);
-	hp = &tmp_heap[0];
+    pectxt.c_p = p;
+    pectxt.reason = reason;
 
-	exit_tuple = TUPLE3(hp, am_EXIT, p->common.id, reason);
+    if (links) {
+        erts_link_tree_foreach_delete(&links,
+                                      erts_proc_exit_handle_link,
+                                      (void *) &pectxt);
+        ASSERT(!links);
+    }
 
-	exit_tuple_sz = size_object(exit_tuple);
+    if (monitors) {
+        erts_monitor_tree_foreach_delete(&monitors,
+                                         erts_proc_exit_handle_monitor,
+                                         (void *) &pectxt);
+        ASSERT(!monitors);
+    }
 
-	{
-	    ExitLinkContext context = {p, reason, exit_tuple, exit_tuple_sz};
-	    erts_sweep_links(lnk, &doit_exit_link, &context);
-	}
-	UnUseTmpHeap(4,p);
+    if (lt_monitors) {
+        erts_monitor_list_foreach_delete(&lt_monitors,
+                                         erts_proc_exit_handle_monitor,
+                                         (void *) &pectxt);
+        ASSERT(!lt_monitors);
     }
 
-    {
-	ExitMonitorContext context = {reason, p};
-	erts_sweep_monitors(mon,&doit_exit_monitor,&context); /* Allocates TmpHeap, but we
-								 have none here */
+    erts_proc_sig_fetch(p);
+    /*
+     * erts_proc_sig_handle_exit() implements yielding.
+     * However, this function cannot handle it yet... loop
+     * until done...
+     */
+    while (!0) {
+        int reds = CONTEXT_REDS;
+        if (erts_proc_sig_handle_exit(p, &reds))
+            break;
     }
 
     erts_proc_lock(p, ERTS_PROC_LOCK_MAIN);
@@ -13272,6 +12952,40 @@ erts_continue_exit_process(Process *p)
     BUMP_ALL_REDS(p);
 }
 
+Process *
+erts_try_lock_sig_free_proc(Eterm pid, ErtsProcLocks locks)
+{
+    Process *rp = erts_proc_lookup_raw(pid);
+    erts_aint32_t state;
+
+    if (!rp)
+        return NULL;
+
+    ERTS_LC_ASSERT(!erts_proc_lc_my_proc_locks(rp));
+
+    state = erts_atomic32_read_nob(&rp->state);
+    if (state & ERTS_PSFLG_EXITING)
+        return NULL;
+
+    if (state & (ERTS_PSFLG_SIG_IN_Q|ERTS_PSFLG_SIG_Q))
+        return ERTS_PROC_LOCK_BUSY;
+    if (erts_proc_trylock(rp, locks) == EBUSY)
+        return ERTS_PROC_LOCK_BUSY;
+
+    state = erts_atomic32_read_nob(&rp->state);
+    if (state & ERTS_PSFLG_EXITING) {
+        erts_proc_unlock(rp, locks);
+        return NULL;
+    }
+
+    if (state & (ERTS_PSFLG_SIG_IN_Q|ERTS_PSFLG_SIG_Q)) {
+        erts_proc_unlock(rp, locks);
+        return ERTS_PROC_LOCK_BUSY;
+    }
+
+    return rp;
+}
+
 /*
  * Stack dump functions follow.
  */
diff --git a/erts/emulator/beam/erl_process.h b/erts/emulator/beam/erl_process.h
index ebf990c837..0550fb05b5 100644
--- a/erts/emulator/beam/erl_process.h
+++ b/erts/emulator/beam/erl_process.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1996-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1996-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -51,7 +51,7 @@ typedef struct process Process;
 #include "erl_process_dict.h"
 #include "erl_node_container_utils.h"
 #include "erl_node_tables.h"
-#include "erl_monitors.h"
+#include "erl_monitor_link.h"
 #include "erl_hl_timer.h"
 #include "erl_time.h"
 #include "erl_atom_table.h"
@@ -75,8 +75,6 @@ typedef struct process Process;
 #include "erl_thr_progress.h"
 #undef ERL_THR_PROGRESS_TSD_TYPE_ONLY
 
-struct ErtsNodesMonitor_;
-
 #define ERTS_HAVE_SCHED_UTIL_BALANCING_SUPPORT_OPT	0
 #define ERTS_HAVE_SCHED_UTIL_BALANCING_SUPPORT		0
 
@@ -311,7 +309,6 @@ typedef enum {
     ERTS_SSI_AUX_WORK_ASYNC_READY_CLEAN_IX,
     ERTS_SSI_AUX_WORK_MISC_THR_PRGR_IX,
     ERTS_SSI_AUX_WORK_MISC_IX,
-    ERTS_SSI_AUX_WORK_PENDING_EXITERS_IX,
     ERTS_SSI_AUX_WORK_SET_TMO_IX,
     ERTS_SSI_AUX_WORK_MSEG_CACHE_CHECK_IX,
     ERTS_SSI_AUX_WORK_YIELD_IX,
@@ -345,8 +342,6 @@ typedef enum {
     (((erts_aint32_t) 1) << ERTS_SSI_AUX_WORK_MISC_THR_PRGR_IX)
 #define ERTS_SSI_AUX_WORK_MISC \
     (((erts_aint32_t) 1) << ERTS_SSI_AUX_WORK_MISC_IX)
-#define ERTS_SSI_AUX_WORK_PENDING_EXITERS \
-    (((erts_aint32_t) 1) << ERTS_SSI_AUX_WORK_PENDING_EXITERS_IX)
 #define ERTS_SSI_AUX_WORK_SET_TMO \
     (((erts_aint32_t) 1) << ERTS_SSI_AUX_WORK_SET_TMO_IX)
 #define ERTS_SSI_AUX_WORK_MSEG_CACHE_CHECK \
@@ -491,7 +486,6 @@ struct ErtsRunQueue_ {
     int wakeup_other_reds;
 
     struct {
-	ErtsProcList *pending_exiters;
 	Uint context_switches;
 	Uint reductions;
 
@@ -986,14 +980,10 @@ struct process {
 
     Process *next;		/* Pointer to next process in run queue */
 
-    struct ErtsNodesMonitor_ *nodes_monitors;
-
-    ErtsSuspendMonitor *suspend_monitors; /* Processes suspended by
-					     this process via
-					     erlang:suspend_process/1 */
-
-    ErlMessageQueue msg;	/* Message queue */
+    ErtsMonitor *suspend_monitors; /* Processes suspended by this process via
+                                      erlang:suspend_process/1 */
 
+    ErtsSignalPrivQueues sig_qs; /* Signal queues */
     ErtsBifTimers *bif_timers;	/* Bif timers aiming at this process */
 
     ProcDict  *dictionary;       /* Process dictionary, may be NULL */
@@ -1052,9 +1042,8 @@ struct process {
     erts_atomic32_t state;  /* Process state flags (see ERTS_PSFLG_*) */
     erts_atomic32_t dirty_state; /* Process dirty state flags (see ERTS_PDSFLG_*) */
 
-    ErlMessageInQueue msg_inq;
+    ErtsSignalInQueue sig_inq;
     ErlTraceMessageQueue *trace_msg_q;
-    ErtsPendExit pending_exit;
     erts_proc_lock_t lock;
     ErtsSchedulerData *scheduler_data;
     Eterm suspendee;
@@ -1088,6 +1077,7 @@ struct process {
 #endif
 };
 
+extern Eterm erts_init_process_id; /* pid of init process */
 extern const Process erts_invalid_process;
 
 #ifdef CHECK_FOR_HOLES
@@ -1164,20 +1154,20 @@ void erts_check_for_holes(Process* p);
 #define ERTS_PSFLG_IN_PRQ_LOW 		ERTS_PSFLG_BIT(3)
 #define ERTS_PSFLG_FREE			ERTS_PSFLG_BIT(4)
 #define ERTS_PSFLG_EXITING		ERTS_PSFLG_BIT(5)
-#define ERTS_PSFLG_PENDING_EXIT		ERTS_PSFLG_BIT(6)
+#define ERTS_PSFLG_UNUSED		ERTS_PSFLG_BIT(6)
 #define ERTS_PSFLG_ACTIVE		ERTS_PSFLG_BIT(7)
 #define ERTS_PSFLG_IN_RUNQ		ERTS_PSFLG_BIT(8)
 #define ERTS_PSFLG_RUNNING		ERTS_PSFLG_BIT(9)
 #define ERTS_PSFLG_SUSPENDED		ERTS_PSFLG_BIT(10)
 #define ERTS_PSFLG_GC			ERTS_PSFLG_BIT(11)
-/* #define ERTS_PSFLG_		        ERTS_PSFLG_BIT(12) */
-#define ERTS_PSFLG_TRAP_EXIT		ERTS_PSFLG_BIT(13)
+#define ERTS_PSFLG_SYS_TASKS		ERTS_PSFLG_BIT(12)
+#define ERTS_PSFLG_SIG_IN_Q		ERTS_PSFLG_BIT(13)
 #define ERTS_PSFLG_ACTIVE_SYS		ERTS_PSFLG_BIT(14)
 #define ERTS_PSFLG_RUNNING_SYS		ERTS_PSFLG_BIT(15)
 #define ERTS_PSFLG_PROXY		ERTS_PSFLG_BIT(16)
 #define ERTS_PSFLG_DELAYED_SYS		ERTS_PSFLG_BIT(17)
 #define ERTS_PSFLG_OFF_HEAP_MSGQ	ERTS_PSFLG_BIT(18)
-/* #define ERTS_PSFLG_			ERTS_PSFLG_BIT(19) */
+#define ERTS_PSFLG_SIG_Q		ERTS_PSFLG_BIT(19)
 #define ERTS_PSFLG_DIRTY_CPU_PROC	ERTS_PSFLG_BIT(20)
 #define ERTS_PSFLG_DIRTY_IO_PROC	ERTS_PSFLG_BIT(21)
 #define ERTS_PSFLG_DIRTY_ACTIVE_SYS	ERTS_PSFLG_BIT(22)
@@ -1196,7 +1186,6 @@ void erts_check_for_holes(Process* p);
 					 | ERTS_PSFLG_IN_PRQ_LOW)
 
 #define ERTS_PSFLGS_VOLATILE_HEAP	(ERTS_PSFLG_EXITING		\
-					 | ERTS_PSFLG_PENDING_EXIT	\
 					 | ERTS_PSFLG_DIRTY_RUNNING	\
 					 | ERTS_PSFLG_DIRTY_RUNNING_SYS)
 
@@ -1379,6 +1368,9 @@ extern int erts_system_profile_ts_type;
 #define F_DIRTY_MAJOR_GC     (1 << 23) /* Dirty major GC scheduled */
 #define F_DIRTY_MINOR_GC     (1 << 24) /* Dirty minor GC scheduled */
 #define F_HIBERNATED         (1 << 25) /* Hibernated */
+#define F_LOCAL_SIGS_ONLY    (1 << 26)
+#define F_TRAP_EXIT          (1 << 27) /* Trapping exit */
+#define F_DEFERRED_SAVED_LAST (1 << 28)
 
 /*
  * F_DISABLE_GC and F_DELAY_GC are similar. Both will prevent
@@ -1444,7 +1436,7 @@ extern int erts_system_profile_ts_type;
 		     | F_TRACE_ARITY_ONLY | F_TRACE_RETURN_TO \
                      | F_TRACE_SILENT | F_TRACE_SCHED_PROCS | F_TRACE_PORTS \
 		     | F_TRACE_SCHED_PORTS | F_TRACE_SCHED_NO \
-		     | F_TRACE_SCHED_EXIT)
+		     | F_TRACE_SCHED_EXIT )
 
 
 #define ERTS_TRACEE_MODIFIER_FLAGS \
@@ -1457,6 +1449,14 @@ extern int erts_system_profile_ts_type;
 
 #define SEQ_TRACE_FLAG(N)        (1 << (ERTS_TRACE_TS_TYPE_BITS + (N)))
 
+#define ERTS_SIG_ENABLE_TRACE_FLAGS \
+    ( F_TRACE_RECEIVE | F_TRACE_PROCS)
+
+/*
+ * F_TRACE_RECEIVE is always enabled/disable via signaling.
+ * F_TRACE_PROCS enable/disable F_TRACE_PROCS_SIG via signaling.
+ */
+
 /* Sequential trace flags */
 
 /* SEQ_TRACE_TIMESTAMP_MASK is a bit-field */
@@ -1483,10 +1483,6 @@ extern int erts_system_profile_ts_type;
 #define DT_UTAG_FLAGS(P)  ((P)->dt_utag_flags) 
 #endif
 
-/* Option flags to erts_send_exit_signal() */
-#define ERTS_XSIG_FLG_IGN_KILL		(((Uint32) 1) << 0)
-#define ERTS_XSIG_FLG_NO_IGN_NORMAL	(((Uint32) 1) << 1)
-
 #define CANCEL_TIMER(P)					\
     do {						\
 	if ((P)->flags & (F_INSLPQUEUE|F_TIMO)) {	\
@@ -1733,6 +1729,7 @@ struct db_fixation;
 void erts_schedule_ets_free_fixation(Eterm pid, struct db_fixation*);
 void erts_schedule_flush_trace_messages(Process *proc, int force_on_proc);
 int erts_flush_trace_messages(Process *c_p, ErtsProcLocks locks);
+int erts_sig_prio(Eterm pid, int prio);
 
 #if defined(ERTS_ENABLE_LOCK_CHECK)
 int erts_dbg_check_halloc_lock(Process *p);
@@ -1781,8 +1778,10 @@ ErtsRunQueue *erts_schedid2runq(Uint);
 Process *erts_schedule(ErtsSchedulerData *, Process*, int);
 void erts_schedule_misc_op(void (*)(void *), void *);
 Eterm erl_create_process(Process*, Eterm, Eterm, Eterm, ErlSpawnOpts*);
+void erts_set_self_exiting(Process *, Eterm);
 void erts_do_exit_process(Process*, Eterm);
 void erts_continue_exit_process(Process *);
+void erts_proc_exit_link(Process *, ErtsLink *, Uint16, Eterm, Eterm);
 /* Begin System profile */
 Uint erts_runnable_process_count(void);
 /* End System profile */
@@ -1799,7 +1798,14 @@ void erts_print_run_queue_info(fmtfn_t, void *to_arg, ErtsRunQueue*);
 void erts_dump_extended_process_state(fmtfn_t to, void *to_arg, erts_aint32_t psflg);
 void erts_dump_process_state(fmtfn_t to, void *to_arg, erts_aint32_t psflg);
 
-Eterm erts_get_process_priority(Process *p);
+typedef struct {
+    Process *c_p;
+    Eterm reason;
+} ErtsProcExitContext;
+void erts_proc_exit_handle_monitor(ErtsMonitor *mon, void *vctxt);
+void erts_proc_exit_handle_link(ErtsLink *lnk, void *vctxt);
+
+Eterm erts_get_process_priority(erts_aint32_t state);
 Eterm erts_set_process_priority(Process *p, Eterm prio);
 
 Uint erts_get_total_context_switches(void);
@@ -1817,18 +1823,6 @@ void erts_suspend(Process*, ErtsProcLocks, Port*);
 void erts_resume(Process*, ErtsProcLocks);
 int erts_resume_processes(ErtsProcList *);
 
-int erts_send_exit_signal(Process *,
-			  Eterm,
-			  Process *,
-			  ErtsProcLocks *,
-			  Eterm,
-			  Eterm,
-			  Process *,
-			  Uint32);
-void erts_handle_pending_exit(Process *, ErtsProcLocks);
-#define ERTS_PROC_PENDING_EXIT(P) \
-    (ERTS_PSFLG_PENDING_EXIT & erts_atomic32_read_acqb(&(P)->state))
-
 void erts_deep_process_dump(fmtfn_t, void *);
 
 Eterm erts_get_reader_groups_map(Process *c_p);
@@ -1860,6 +1854,8 @@ do {										\
 ErtsSchedulerData *erts_get_scheduler_data(void);
 
 void erts_schedule_process(Process *, erts_aint32_t, ErtsProcLocks);
+erts_aint32_t erts_proc_sys_schedule(Process *p, erts_aint32_t state,
+                                     erts_aint32_t enable_flag);
 
 ERTS_GLB_INLINE void erts_proc_notify_new_message(Process *p, ErtsProcLocks locks);
 ERTS_GLB_INLINE void erts_schedule_dirty_sys_execution(Process *c_p);
@@ -1891,8 +1887,7 @@ erts_schedule_dirty_sys_execution(Process *c_p)
     /* Don't set dirty-active-sys if we are about to exit... */
 
     while (!(a & (ERTS_PSFLG_DIRTY_ACTIVE_SYS
-                  | ERTS_PSFLG_EXITING
-                  | ERTS_PSFLG_PENDING_EXIT))) {
+                  | ERTS_PSFLG_EXITING))) {
         e = a;
         n = a | ERTS_PSFLG_DIRTY_ACTIVE_SYS;
         a = erts_atomic32_cmpxchg_mb(&c_p->state, n, e);
@@ -2313,6 +2308,8 @@ erts_try_change_runq_proc(Process *p, ErtsRunQueue *rq)
 {
     erts_aint_t old_rqint, new_rqint;
 
+    ASSERT(rq);
+
     new_rqint = (erts_aint_t) rq;
     old_rqint = (erts_aint_t) erts_atomic_read_nob(&p->run_queue);
     while (1) {
@@ -2577,6 +2574,8 @@ ERTS_TIME2REDS_IMPL__(ErtsMonotonicTime start, ErtsMonotonicTime end)
 }
 #endif
 
+Process *erts_try_lock_sig_free_proc(Eterm pid,
+                                     ErtsProcLocks locks);
 
 Process *erts_pid2proc_not_running(Process *,
 				   ErtsProcLocks,
diff --git a/erts/emulator/beam/erl_process_dump.c b/erts/emulator/beam/erl_process_dump.c
index 05e7bcdea2..00659f9f49 100644
--- a/erts/emulator/beam/erl_process_dump.c
+++ b/erts/emulator/beam/erl_process_dump.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2003-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2003-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -35,6 +35,7 @@
 #include "erl_map.h"
 #define ERTS_WANT_EXTERNAL_TAGS
 #include "external.h"
+#include "erl_proc_sig_queue.h"
 
 #define PTR_FMT "%bpX"
 #define ETERM_FMT "%beX"
@@ -96,17 +97,35 @@ erts_deep_process_dump(fmtfn_t to, void *to_arg)
     dump_binaries(to, to_arg, all_binaries);
 }
 
+static void
+monitor_size(ErtsMonitor *mon, void *vsize)
+{
+    *((Uint *) vsize) += erts_monitor_size(mon);
+}
+
+static void
+link_size(ErtsMonitor *lnk, void *vsize)
+{
+    *((Uint *) vsize) += erts_link_size(lnk);
+}
+
 Uint erts_process_memory(Process *p, int incl_msg_inq) {
-  ErtsMessage *mp;
   Uint size = 0;
   struct saved_calls *scb;
   size += sizeof(Process);
 
-  if (incl_msg_inq)
-      ERTS_MSGQ_MV_INQ2PRIVQ(p);
+  if (incl_msg_inq) {
+      erts_proc_lock(p, ERTS_PROC_LOCK_MSGQ);
+      erts_proc_sig_fetch(p);
+      erts_proc_unlock(p, ERTS_PROC_LOCK_MSGQ);
+  }
 
-  erts_doforall_links(ERTS_P_LINKS(p), &erts_one_link_size, &size);
-  erts_doforall_monitors(ERTS_P_MONITORS(p), &erts_one_mon_size, &size);
+  erts_link_tree_foreach(ERTS_P_LINKS(p),
+                         link_size, (void *) &size);
+  erts_monitor_tree_foreach(ERTS_P_MONITORS(p),
+                            monitor_size, (void *) &size);
+  erts_monitor_list_foreach(ERTS_P_LT_MONITORS(p),
+                            monitor_size, (void *) &size);
   size += (p->heap_sz + p->mbuf_sz) * sizeof(Eterm);
   if (p->abandoned_heap)
       size += (p->hend - p->heap) * sizeof(Eterm);
@@ -114,11 +133,16 @@ Uint erts_process_memory(Process *p, int incl_msg_inq) {
     size += (p->old_hend - p->old_heap) * sizeof(Eterm);
 
 
-  size += p->msg.len * sizeof(ErtsMessage);
+  size += p->sig_qs.len * sizeof(ErtsMessage);
 
-  for (mp = p->msg.first; mp; mp = mp->next)
-    if (mp->data.attached)
-      size += erts_msg_attached_data_size(mp)*sizeof(Eterm);
+  ERTS_FOREACH_SIG_PRIVQS(
+      p, mp,
+      {
+          if (ERTS_SIG_IS_NON_MSG((ErtsSignal *) mp))
+              size += erts_proc_sig_signal_size((ErtsSignal *) mp);
+          else if (mp->data.attached)
+              size += erts_msg_attached_data_size(mp) * sizeof(Eterm);
+      });
 
   if (p->arg_reg != p->def_arg_reg) {
     size += p->arity * sizeof(p->arg_reg[0]);
@@ -137,31 +161,48 @@ Uint erts_process_memory(Process *p, int incl_msg_inq) {
   return size;
 }
 
+static ERTS_INLINE void
+dump_msg(fmtfn_t to, void *to_arg, ErtsMessage *mp)
+{
+    if (ERTS_SIG_IS_MSG((ErtsSignal *) mp)) {
+        Eterm mesg = ERL_MESSAGE_TERM(mp);
+        if (is_value(mesg))
+            dump_element(to, to_arg, mesg);
+        else
+            dump_dist_ext(to, to_arg, mp->data.dist_ext);
+        mesg = ERL_MESSAGE_TOKEN(mp);
+        erts_print(to, to_arg, ":");
+        dump_element(to, to_arg, mesg);
+        erts_print(to, to_arg, "\n");
+    }
+}
+
+static ERTS_INLINE void
+heap_dump_msg(fmtfn_t to, void *to_arg, ErtsMessage *mp)
+{
+    if (ERTS_SIG_IS_MSG((ErtsSignal *) mp)) {
+        Eterm mesg = ERL_MESSAGE_TERM(mp);
+        if (is_value(mesg))
+            heap_dump(to, to_arg, mesg);
+        mesg = ERL_MESSAGE_TOKEN(mp);
+        heap_dump(to, to_arg, mesg);
+    }
+}
+
 static void
 dump_process_info(fmtfn_t to, void *to_arg, Process *p)
 {
     Eterm* sp;
-    ErtsMessage* mp;
     int yreg = -1;
 
     if (ERTS_TRACE_FLAGS(p) & F_SENSITIVE)
         return;
 
-    ERTS_MSGQ_MV_INQ2PRIVQ(p);
+    erts_proc_sig_fetch(p);
 
-    if (p->msg.first) {
+    if (p->sig_qs.first || p->sig_qs.cont) {
 	erts_print(to, to_arg, "=proc_messages:%T\n", p->common.id);
-	for (mp = p->msg.first; mp != NULL; mp = mp->next) {
-	    Eterm mesg = ERL_MESSAGE_TERM(mp);
-	    if (is_value(mesg))
-		dump_element(to, to_arg, mesg);
-	    else
-		dump_dist_ext(to, to_arg, mp->data.dist_ext);
-	    mesg = ERL_MESSAGE_TOKEN(mp);
-	    erts_print(to, to_arg, ":");
-	    dump_element(to, to_arg, mesg);
-	    erts_print(to, to_arg, "\n");
-	}
+        ERTS_FOREACH_SIG_PRIVQS(p, mp, dump_msg(to, to_arg, mp));
     }
 
     if (p->dictionary) {
@@ -183,13 +224,10 @@ dump_process_info(fmtfn_t to, void *to_arg, Process *p)
             heap_dump(to, to_arg, term);
         }
     }
-    for (mp = p->msg.first; mp != NULL; mp = mp->next) {
-        Eterm mesg = ERL_MESSAGE_TERM(mp);
-        if (is_value(mesg))
-            heap_dump(to, to_arg, mesg);
-        mesg = ERL_MESSAGE_TOKEN(mp);
-        heap_dump(to, to_arg, mesg);
-    }
+
+    if (p->sig_qs.first || p->sig_qs.cont)
+        ERTS_FOREACH_SIG_PRIVQS(p, mp, heap_dump_msg(to, to_arg, mp));
+
     if (p->dictionary) {
         erts_deep_dictionary_dump(to, to_arg, p->dictionary, heap_dump);
     }
@@ -997,8 +1035,8 @@ erts_dump_extended_process_state(fmtfn_t to, void *to_arg, erts_aint32_t psflg)
                 erts_print(to, to_arg, "FREE"); break;
             case ERTS_PSFLG_EXITING:
                 erts_print(to, to_arg, "EXITING"); break;
-            case ERTS_PSFLG_PENDING_EXIT:
-                erts_print(to, to_arg, "PENDING_EXIT"); break;
+            case ERTS_PSFLG_UNUSED:
+                erts_print(to, to_arg, "UNUSED"); break;
             case ERTS_PSFLG_ACTIVE:
                 erts_print(to, to_arg, "ACTIVE"); break;
             case ERTS_PSFLG_IN_RUNQ:
@@ -1009,8 +1047,10 @@ erts_dump_extended_process_state(fmtfn_t to, void *to_arg, erts_aint32_t psflg)
                 erts_print(to, to_arg, "SUSPENDED"); break;
             case ERTS_PSFLG_GC:
                 erts_print(to, to_arg, "GC"); break;
-            case ERTS_PSFLG_TRAP_EXIT:
-                erts_print(to, to_arg, "TRAP_EXIT"); break;
+            case ERTS_PSFLG_SYS_TASKS:
+                erts_print(to, to_arg, "SYS_TASKS"); break;
+            case ERTS_PSFLG_SIG_IN_Q:
+                erts_print(to, to_arg, "SIG_IN_Q"); break;
             case ERTS_PSFLG_ACTIVE_SYS:
                 erts_print(to, to_arg, "ACTIVE_SYS"); break;
             case ERTS_PSFLG_RUNNING_SYS:
@@ -1021,6 +1061,8 @@ erts_dump_extended_process_state(fmtfn_t to, void *to_arg, erts_aint32_t psflg)
                 erts_print(to, to_arg, "DELAYED_SYS"); break;
             case ERTS_PSFLG_OFF_HEAP_MSGQ:
                 erts_print(to, to_arg, "OFF_HEAP_MSGQ"); break;
+            case ERTS_PSFLG_SIG_Q:
+                erts_print(to, to_arg, "SIG_Q"); break;
             case ERTS_PSFLG_DIRTY_CPU_PROC:
                 erts_print(to, to_arg, "DIRTY_CPU_PROC"); break;
             case ERTS_PSFLG_DIRTY_IO_PROC:
diff --git a/erts/emulator/beam/erl_process_lock.c b/erts/emulator/beam/erl_process_lock.c
index 431867f27e..44c7892040 100644
--- a/erts/emulator/beam/erl_process_lock.c
+++ b/erts/emulator/beam/erl_process_lock.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2007-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2007-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -101,7 +101,6 @@ static void cleanup_tse(void);
 #ifdef ERTS_ENABLE_LOCK_CHECK
 static struct {
     Sint16 proc_lock_main;
-    Sint16 proc_lock_link;
     Sint16 proc_lock_msgq;
     Sint16 proc_lock_btm;
     Sint16 proc_lock_status;
@@ -140,7 +139,6 @@ erts_init_proc_lock(int cpus)
 #endif
 #ifdef ERTS_ENABLE_LOCK_CHECK
     lc_id.proc_lock_main	= erts_lc_get_lock_order_id("proc_main");
-    lc_id.proc_lock_link	= erts_lc_get_lock_order_id("proc_link");
     lc_id.proc_lock_msgq	= erts_lc_get_lock_order_id("proc_msgq");
     lc_id.proc_lock_btm		= erts_lc_get_lock_order_id("proc_btm");
     lc_id.proc_lock_status	= erts_lc_get_lock_order_id("proc_status");
@@ -1055,12 +1053,6 @@ erts_proc_lock_init(Process *p)
 #ifdef ERTS_ENABLE_LOCK_CHECK
     erts_lc_trylock(1, &p->lock.main.lc);
 #endif
-    erts_mtx_init(&p->lock.link, "proc_link", p->common.id,
-        ERTS_LOCK_FLAGS_CATEGORY_PROCESS);
-    ethr_mutex_lock(&p->lock.link.mtx);
-#ifdef ERTS_ENABLE_LOCK_CHECK
-    erts_lc_trylock(1, &p->lock.link.lc);
-#endif
     erts_mtx_init(&p->lock.msgq, "proc_msgq", p->common.id,
         ERTS_LOCK_FLAGS_CATEGORY_PROCESS);
     ethr_mutex_lock(&p->lock.msgq.mtx);
@@ -1102,7 +1094,6 @@ erts_proc_lock_fin(Process *p)
 {
 #if ERTS_PROC_LOCK_RAW_MUTEX_IMPL
     erts_mtx_destroy(&p->lock.main);
-    erts_mtx_destroy(&p->lock.link);
     erts_mtx_destroy(&p->lock.msgq);
     erts_mtx_destroy(&p->lock.btm);
     erts_mtx_destroy(&p->lock.status);
@@ -1144,8 +1135,6 @@ void erts_lcnt_enable_proc_lock_count(Process *proc, int enable) {
 
         erts_lcnt_init_lock_info_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_MAIN,
             "proc_main", proc->common.id, ERTS_LOCK_TYPE_PROCLOCK);
-        erts_lcnt_init_lock_info_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_LINK,
-            "proc_link", proc->common.id, ERTS_LOCK_TYPE_PROCLOCK);
         erts_lcnt_init_lock_info_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_MSGQ,
             "proc_msgq", proc->common.id, ERTS_LOCK_TYPE_PROCLOCK);
         erts_lcnt_init_lock_info_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_BTM,
@@ -1200,10 +1189,6 @@ erts_proc_lc_lock(Process *p, ErtsProcLocks locks, char *file, unsigned int line
 	lck.id = lc_id.proc_lock_main;
 	erts_lc_lock_x(&lck,file,line);
     }
-    if (locks & ERTS_PROC_LOCK_LINK) {
-	lck.id = lc_id.proc_lock_link;
-	erts_lc_lock_x(&lck,file,line);
-    }
     if (locks & ERTS_PROC_LOCK_MSGQ) {
 	lck.id = lc_id.proc_lock_msgq;
 	erts_lc_lock_x(&lck,file,line);
@@ -1233,10 +1218,6 @@ erts_proc_lc_trylock(Process *p, ErtsProcLocks locks, int locked,
 	lck.id = lc_id.proc_lock_main;
 	erts_lc_trylock_x(locked, &lck, file, line);
     }
-    if (locks & ERTS_PROC_LOCK_LINK) {
-	lck.id = lc_id.proc_lock_link;
-	erts_lc_trylock_x(locked, &lck, file, line);
-    }
     if (locks & ERTS_PROC_LOCK_MSGQ) {
 	lck.id = lc_id.proc_lock_msgq;
 	erts_lc_trylock_x(locked, &lck, file, line);
@@ -1277,10 +1258,6 @@ erts_proc_lc_unlock(Process *p, ErtsProcLocks locks)
 	lck.id = lc_id.proc_lock_msgq;
 	erts_lc_unlock(&lck);
     }
-    if (locks & ERTS_PROC_LOCK_LINK) {
-	lck.id = lc_id.proc_lock_link;
-	erts_lc_unlock(&lck);
-    }
     if (locks & ERTS_PROC_LOCK_MAIN) {
 	lck.id = lc_id.proc_lock_main;
 	erts_lc_unlock(&lck);
@@ -1312,10 +1289,6 @@ erts_proc_lc_might_unlock(Process *p, ErtsProcLocks locks)
 	lck.id = lc_id.proc_lock_msgq;
 	erts_lc_might_unlock(&lck);
     }
-    if (locks & ERTS_PROC_LOCK_LINK) {
-	lck.id = lc_id.proc_lock_link;
-	erts_lc_might_unlock(&lck);
-    }
     if (locks & ERTS_PROC_LOCK_MAIN) {
 	lck.id = lc_id.proc_lock_main;
 	erts_lc_might_unlock(&lck);
@@ -1323,8 +1296,6 @@ erts_proc_lc_might_unlock(Process *p, ErtsProcLocks locks)
 #elif ERTS_PROC_LOCK_RAW_MUTEX_IMPL
     if (locks & ERTS_PROC_LOCK_MAIN)
 	erts_lc_might_unlock(&p->lock.main.lc);
-    if (locks & ERTS_PROC_LOCK_LINK)
-	erts_lc_might_unlock(&p->lock.link.lc);
     if (locks & ERTS_PROC_LOCK_MSGQ)
 	erts_lc_might_unlock(&p->lock.msgq.lc);
     if (locks & ERTS_PROC_LOCK_BTM)
@@ -1348,10 +1319,6 @@ erts_proc_lc_require_lock(Process *p, ErtsProcLocks locks, char *file,
 	lck.id = lc_id.proc_lock_main;
 	erts_lc_require_lock(&lck, file, line);
     }
-    if (locks & ERTS_PROC_LOCK_LINK) {
-	lck.id = lc_id.proc_lock_link;
-	erts_lc_require_lock(&lck, file, line);
-    }
     if (locks & ERTS_PROC_LOCK_MSGQ) {
 	lck.id = lc_id.proc_lock_msgq;
 	erts_lc_require_lock(&lck, file, line);
@@ -1371,8 +1338,6 @@ erts_proc_lc_require_lock(Process *p, ErtsProcLocks locks, char *file,
 #elif ERTS_PROC_LOCK_RAW_MUTEX_IMPL
     if (locks & ERTS_PROC_LOCK_MAIN)
 	erts_lc_require_lock(&p->lock.main.lc, file, line);
-    if (locks & ERTS_PROC_LOCK_LINK)
-	erts_lc_require_lock(&p->lock.link.lc, file, line);
     if (locks & ERTS_PROC_LOCK_MSGQ)
 	erts_lc_require_lock(&p->lock.msgq.lc, file, line);
     if (locks & ERTS_PROC_LOCK_BTM)
@@ -1407,10 +1372,6 @@ erts_proc_lc_unrequire_lock(Process *p, ErtsProcLocks locks)
 	lck.id = lc_id.proc_lock_msgq;
 	erts_lc_unrequire_lock(&lck);
     }
-    if (locks & ERTS_PROC_LOCK_LINK) {
-	lck.id = lc_id.proc_lock_link;
-	erts_lc_unrequire_lock(&lck);
-    }
     if (locks & ERTS_PROC_LOCK_MAIN) {
 	lck.id = lc_id.proc_lock_main;
 	erts_lc_unrequire_lock(&lck);
@@ -1418,8 +1379,6 @@ erts_proc_lc_unrequire_lock(Process *p, ErtsProcLocks locks)
 #elif ERTS_PROC_LOCK_RAW_MUTEX_IMPL
     if (locks & ERTS_PROC_LOCK_MAIN)
 	erts_lc_unrequire_lock(&p->lock.main.lc);
-    if (locks & ERTS_PROC_LOCK_LINK)
-	erts_lc_unrequire_lock(&p->lock.link.lc);
     if (locks & ERTS_PROC_LOCK_MSGQ)
 	erts_lc_unrequire_lock(&p->lock.msgq.lc);
     if (locks & ERTS_PROC_LOCK_BTM)
@@ -1443,8 +1402,6 @@ erts_proc_lc_trylock_force_busy(Process *p, ErtsProcLocks locks)
 
 	if (locks & ERTS_PROC_LOCK_MAIN)
 	    lck.id = lc_id.proc_lock_main;
-	else if (locks & ERTS_PROC_LOCK_LINK)
-	    lck.id = lc_id.proc_lock_link;
 	else if (locks & ERTS_PROC_LOCK_MSGQ)
 	    lck.id = lc_id.proc_lock_msgq;
 	else if (locks & ERTS_PROC_LOCK_BTM)
@@ -1487,10 +1444,6 @@ void erts_proc_lc_chk_only_proc(Process *p, ErtsProcLocks locks)
 	have_locks[have_locks_len].id = lc_id.proc_lock_main;
 	have_locks[have_locks_len++].extra = p->common.id;
     }
-    if (locks & ERTS_PROC_LOCK_LINK) {
-	have_locks[have_locks_len].id = lc_id.proc_lock_link;
-	have_locks[have_locks_len++].extra = p->common.id;
-    }
     if (locks & ERTS_PROC_LOCK_MSGQ) {
 	have_locks[have_locks_len].id = lc_id.proc_lock_msgq;
 	have_locks[have_locks_len++].extra = p->common.id;
@@ -1511,8 +1464,6 @@ void erts_proc_lc_chk_only_proc(Process *p, ErtsProcLocks locks)
     erts_lc_lock_t have_locks[6];
     if (locks & ERTS_PROC_LOCK_MAIN)
 	have_locks[have_locks_len++] = p->lock.main.lc;
-    if (locks & ERTS_PROC_LOCK_LINK)
-	have_locks[have_locks_len++] = p->lock.link.lc;
     if (locks & ERTS_PROC_LOCK_MSGQ)
 	have_locks[have_locks_len++] = p->lock.msgq.lc;
     if (locks & ERTS_PROC_LOCK_BTM)
@@ -1540,10 +1491,6 @@ erts_proc_lc_chk_have_proc_locks(Process *p, ErtsProcLocks locks)
 	have_locks[have_locks_len].id = lc_id.proc_lock_main;
 	have_locks[have_locks_len++].extra = p->common.id;
     }
-    if (locks & ERTS_PROC_LOCK_LINK) {
-	have_locks[have_locks_len].id = lc_id.proc_lock_link;
-	have_locks[have_locks_len++].extra = p->common.id;
-    }
     if (locks & ERTS_PROC_LOCK_MSGQ) {
 	have_locks[have_locks_len].id = lc_id.proc_lock_msgq;
 	have_locks[have_locks_len++].extra = p->common.id;
@@ -1564,8 +1511,6 @@ erts_proc_lc_chk_have_proc_locks(Process *p, ErtsProcLocks locks)
     erts_lc_lock_t have_locks[6];
     if (locks & ERTS_PROC_LOCK_MAIN)
 	have_locks[have_locks_len++] = p->lock.main.lc;
-    if (locks & ERTS_PROC_LOCK_LINK)
-	have_locks[have_locks_len++] = p->lock.link.lc;
     if (locks & ERTS_PROC_LOCK_MSGQ)
 	have_locks[have_locks_len++] = p->lock.msgq.lc;
     if (locks & ERTS_PROC_LOCK_BTM)
@@ -1603,14 +1548,6 @@ erts_proc_lc_chk_proc_locks(Process *p, ErtsProcLocks locks)
 	have_not_locks[have_not_locks_len].id = lc_id.proc_lock_main;
 	have_not_locks[have_not_locks_len++].extra = p->common.id;
     }
-    if (locks & ERTS_PROC_LOCK_LINK) {
-	have_locks[have_locks_len].id = lc_id.proc_lock_link;
-	have_locks[have_locks_len++].extra = p->common.id;
-    }
-    else {
-	have_not_locks[have_not_locks_len].id = lc_id.proc_lock_link;
-	have_not_locks[have_not_locks_len++].extra = p->common.id;
-    }
     if (locks & ERTS_PROC_LOCK_MSGQ) {
 	have_locks[have_locks_len].id = lc_id.proc_lock_msgq;
 	have_locks[have_locks_len++].extra = p->common.id;
@@ -1651,10 +1588,6 @@ erts_proc_lc_chk_proc_locks(Process *p, ErtsProcLocks locks)
 	have_locks[have_locks_len++] = p->lock.main.lc;
     else
 	have_not_locks[have_not_locks_len++] = p->lock.main.lc;
-    if (locks & ERTS_PROC_LOCK_LINK)
-	have_locks[have_locks_len++] = p->lock.link.lc;
-    else
-	have_not_locks[have_not_locks_len++] = p->lock.link.lc;
     if (locks & ERTS_PROC_LOCK_MSGQ)
 	have_locks[have_locks_len++] = p->lock.msgq.lc;
     else
@@ -1680,13 +1613,10 @@ erts_proc_lc_chk_proc_locks(Process *p, ErtsProcLocks locks)
 ErtsProcLocks
 erts_proc_lc_my_proc_locks(Process *p)
 {
-    int resv[6];
+    int resv[5];
     ErtsProcLocks res = 0;
 #if ERTS_PROC_LOCK_OWN_IMPL
-    erts_lc_lock_t locks[6] = {ERTS_LC_LOCK_INIT(lc_id.proc_lock_main,
-						 p->common.id,
-						 ERTS_LOCK_TYPE_PROCLOCK),
-			       ERTS_LC_LOCK_INIT(lc_id.proc_lock_link,
+    erts_lc_lock_t locks[5] = {ERTS_LC_LOCK_INIT(lc_id.proc_lock_main,
 						 p->common.id,
 						 ERTS_LOCK_TYPE_PROCLOCK),
 			       ERTS_LC_LOCK_INIT(lc_id.proc_lock_msgq,
@@ -1702,26 +1632,23 @@ erts_proc_lc_my_proc_locks(Process *p)
 						 p->common.id,
 						 ERTS_LOCK_TYPE_PROCLOCK)};
 #elif ERTS_PROC_LOCK_RAW_MUTEX_IMPL
-    erts_lc_lock_t locks[6] = {p->lock.main.lc,
-			       p->lock.link.lc,
+    erts_lc_lock_t locks[5] = {p->lock.main.lc,
 			       p->lock.msgq.lc,
 			       p->lock.btm.lc,
 			       p->lock.status.lc,
 			       p->lock.trace.lc};
 #endif
 
-    erts_lc_have_locks(resv, locks, 6);
+    erts_lc_have_locks(resv, locks, 5);
     if (resv[0])
 	res |= ERTS_PROC_LOCK_MAIN;
     if (resv[1])
-	res |= ERTS_PROC_LOCK_LINK;
-    if (resv[2])
 	res |= ERTS_PROC_LOCK_MSGQ;
-    if (resv[3])
+    if (resv[2])
 	res |= ERTS_PROC_LOCK_BTM;
-    if (resv[4])
+    if (resv[3])
 	res |= ERTS_PROC_LOCK_STATUS;
-    if (resv[5])
+    if (resv[4])
 	res |= ERTS_PROC_LOCK_TRACE;
 
     return res;
@@ -1730,15 +1657,14 @@ erts_proc_lc_my_proc_locks(Process *p)
 void
 erts_proc_lc_chk_no_proc_locks(char *file, int line)
 {
-    int resv[6];
-    int ids[6] = {lc_id.proc_lock_main,
-		  lc_id.proc_lock_link,
+    int resv[5];
+    int ids[5] = {lc_id.proc_lock_main,
 		  lc_id.proc_lock_msgq,
 		  lc_id.proc_lock_btm,
 		  lc_id.proc_lock_status,
 		  lc_id.proc_lock_trace};
-    erts_lc_have_lock_ids(resv, ids, 6);
-    if (!ERTS_IS_CRASH_DUMPING && (resv[0] || resv[1] || resv[2] || resv[3] || resv[4] || resv[5])) {
+    erts_lc_have_lock_ids(resv, ids, 5);
+    if (!ERTS_IS_CRASH_DUMPING && (resv[0] || resv[1] || resv[2] || resv[3] || resv[4])) {
 	erts_lc_fail("%s:%d: Thread has process locks locked when expected "
 		     "not to have any process locks locked",
 		     file, line);
diff --git a/erts/emulator/beam/erl_process_lock.h b/erts/emulator/beam/erl_process_lock.h
index 9d5691d3c4..43f396c547 100644
--- a/erts/emulator/beam/erl_process_lock.h
+++ b/erts/emulator/beam/erl_process_lock.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  * 
- * Copyright Ericsson AB 2007-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2007-2018. All Rights Reserved.
  * 
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -66,7 +66,7 @@
 
 #endif
 
-#define ERTS_PROC_LOCK_MAX_BIT 5
+#define ERTS_PROC_LOCK_MAX_BIT 4
 
 typedef erts_aint32_t ErtsProcLocks;
 
@@ -82,19 +82,17 @@ typedef struct erts_proc_lock_t_ {
     /* Each erts_mtx_t has its own lock counter ^ */
 
     #define ERTS_LCNT_PROCLOCK_IDX_MAIN 0
-    #define ERTS_LCNT_PROCLOCK_IDX_LINK 1
-    #define ERTS_LCNT_PROCLOCK_IDX_MSGQ 2
-    #define ERTS_LCNT_PROCLOCK_IDX_BTM 3
-    #define ERTS_LCNT_PROCLOCK_IDX_STATUS 4
-    #define ERTS_LCNT_PROCLOCK_IDX_TRACE 5
+    #define ERTS_LCNT_PROCLOCK_IDX_MSGQ 1
+    #define ERTS_LCNT_PROCLOCK_IDX_BTM 2
+    #define ERTS_LCNT_PROCLOCK_IDX_STATUS 3
+    #define ERTS_LCNT_PROCLOCK_IDX_TRACE 4
 
-    #define ERTS_LCNT_PROCLOCK_COUNT 6
+    #define ERTS_LCNT_PROCLOCK_COUNT 5
 
     erts_lcnt_ref_t lcnt_carrier;
 #endif
 #elif ERTS_PROC_LOCK_RAW_MUTEX_IMPL
     erts_mtx_t main;
-    erts_mtx_t link;
     erts_mtx_t msgq;
     erts_mtx_t btm;
     erts_mtx_t status;
@@ -118,27 +116,18 @@ typedef struct erts_proc_lock_t_ {
 #define ERTS_PROC_LOCK_MAIN		(((ErtsProcLocks) 1) << 0)
 
 /*
- * Link lock:
- *   Protects the following fields in the process structure:
- *   * nlinks
- *   * monitors
- *   * suspend_monitors
- */
-#define ERTS_PROC_LOCK_LINK		(((ErtsProcLocks) 1) << 1)
-
-/*
  * Message queue lock:
  *   Protects the following fields in the process structure:
  *   * msg_inq
  */
-#define ERTS_PROC_LOCK_MSGQ		(((ErtsProcLocks) 1) << 2)
+#define ERTS_PROC_LOCK_MSGQ		(((ErtsProcLocks) 1) << 1)
 
 /*
  * Bif timer lock:
  *   Protects the following fields in the process structure:
  *   * bif_timers
  */
-#define ERTS_PROC_LOCK_BTM		(((ErtsProcLocks) 1) << 3)
+#define ERTS_PROC_LOCK_BTM		(((ErtsProcLocks) 1) << 2)
 
 /*
  * Status lock:
@@ -148,7 +137,7 @@ typedef struct erts_proc_lock_t_ {
  *   * sys_tasks
  *   * ...
  */
-#define ERTS_PROC_LOCK_STATUS		(((ErtsProcLocks) 1) << 4)
+#define ERTS_PROC_LOCK_STATUS		(((ErtsProcLocks) 1) << 3)
 
 /*
  * Trace message lock:
@@ -277,9 +266,6 @@ void erts_lcnt_proc_lock(erts_proc_lock_t *lock, ErtsProcLocks locks) {
         if (locks & ERTS_PROC_LOCK_MAIN) {
             erts_lcnt_lock_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_MAIN);
         }
-        if (locks & ERTS_PROC_LOCK_LINK) {
-            erts_lcnt_lock_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_LINK);
-        }
         if (locks & ERTS_PROC_LOCK_MSGQ) {
             erts_lcnt_lock_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_MSGQ);
         }
@@ -307,9 +293,6 @@ void erts_lcnt_proc_lock_post_x(erts_proc_lock_t *lock, ErtsProcLocks locks,
         if (locks & ERTS_PROC_LOCK_MAIN) {
             erts_lcnt_lock_post_x_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_MAIN, file, line);
         }
-        if (locks & ERTS_PROC_LOCK_LINK) {
-            erts_lcnt_lock_post_x_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_LINK, file, line);
-        }
         if (locks & ERTS_PROC_LOCK_MSGQ) {
             erts_lcnt_lock_post_x_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_MSGQ, file, line);
         }
@@ -336,9 +319,6 @@ void erts_lcnt_proc_lock_unacquire(erts_proc_lock_t *lock, ErtsProcLocks locks)
         if (locks & ERTS_PROC_LOCK_MAIN) {
             erts_lcnt_lock_unacquire_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_MAIN);
         }
-        if (locks & ERTS_PROC_LOCK_LINK) {
-            erts_lcnt_lock_unacquire_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_LINK);
-        }
         if (locks & ERTS_PROC_LOCK_MSGQ) {
             erts_lcnt_lock_unacquire_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_MSGQ);
         }
@@ -365,9 +345,6 @@ void erts_lcnt_proc_unlock(erts_proc_lock_t *lock, ErtsProcLocks locks) {
         if (locks & ERTS_PROC_LOCK_MAIN) {
             erts_lcnt_unlock_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_MAIN);
         }
-        if (locks & ERTS_PROC_LOCK_LINK) {
-            erts_lcnt_unlock_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_LINK);
-        }
         if (locks & ERTS_PROC_LOCK_MSGQ) {
             erts_lcnt_unlock_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_MSGQ);
         }
@@ -394,9 +371,6 @@ void erts_lcnt_proc_trylock(erts_proc_lock_t *lock, ErtsProcLocks locks, int res
         if (locks & ERTS_PROC_LOCK_MAIN) {
             erts_lcnt_trylock_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_MAIN, res);
         }
-        if (locks & ERTS_PROC_LOCK_LINK) {
-            erts_lcnt_trylock_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_LINK, res);
-        }
         if (locks & ERTS_PROC_LOCK_MSGQ) {
             erts_lcnt_trylock_idx(carrier, ERTS_LCNT_PROCLOCK_IDX_MSGQ, res);
         }
@@ -640,9 +614,6 @@ erts_proc_raw_trylock__(Process *p, ErtsProcLocks locks)
     if (locks & ERTS_PROC_LOCK_MAIN)
 	if (erts_mtx_trylock(&p->lock.main) == EBUSY)
 	    goto busy_main;
-    if (locks & ERTS_PROC_LOCK_LINK)
-	if (erts_mtx_trylock(&p->lock.link) == EBUSY)
-	    goto busy_link;
     if (locks & ERTS_PROC_LOCK_MSGQ)
 	if (erts_mtx_trylock(&p->lock.msgq) == EBUSY)
 	    goto busy_msgq;
@@ -668,9 +639,6 @@ busy_btm:
     if (locks & ERTS_PROC_LOCK_MSGQ)
 	erts_mtx_unlock(&p->lock.msgq);
 busy_msgq:
-    if (locks & ERTS_PROC_LOCK_LINK)
-	erts_mtx_unlock(&p->lock.link);
-busy_link:
     if (locks & ERTS_PROC_LOCK_MAIN)
 	erts_mtx_unlock(&p->lock.main);
 busy_main:
@@ -741,8 +709,6 @@ erts_proc_lock__(Process *p,
 #elif ERTS_PROC_LOCK_RAW_MUTEX_IMPL
     if (locks & ERTS_PROC_LOCK_MAIN)
 	erts_mtx_lock(&p->lock.main);
-    if (locks & ERTS_PROC_LOCK_LINK)
-	erts_mtx_lock(&p->lock.link);
     if (locks & ERTS_PROC_LOCK_MSGQ)
 	erts_mtx_lock(&p->lock.msgq);
     if (locks & ERTS_PROC_LOCK_BTM)
@@ -844,8 +810,6 @@ erts_proc_unlock__(Process *p,
 	erts_mtx_unlock(&p->lock.btm);
     if (locks & ERTS_PROC_LOCK_MSGQ)
 	erts_mtx_unlock(&p->lock.msgq);
-    if (locks & ERTS_PROC_LOCK_LINK)
-	erts_mtx_unlock(&p->lock.link);
     if (locks & ERTS_PROC_LOCK_MAIN)
 	erts_mtx_unlock(&p->lock.main);
 #endif
diff --git a/erts/emulator/beam/erl_ptab.h b/erts/emulator/beam/erl_ptab.h
index 4858cc8ab8..94f0247492 100644
--- a/erts/emulator/beam/erl_ptab.h
+++ b/erts/emulator/beam/erl_ptab.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2012-2016. All Rights Reserved.
+ * Copyright Ericsson AB 2012-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -35,7 +35,7 @@
 #include "erl_thr_progress.h"
 #undef ERL_THR_PROGRESS_TSD_TYPE_ONLY
 #include "erl_alloc.h"
-#include "erl_monitors.h"
+#include "erl_monitor_link.h"
 
 #define ERTS_TRACER(P)          ((P)->common.tracer)
 #define ERTS_TRACER_MODULE(T) 	(CAR(list_val(T)))
@@ -44,6 +44,7 @@
 
 #define ERTS_P_LINKS(P)		((P)->common.u.alive.links)
 #define ERTS_P_MONITORS(P)	((P)->common.u.alive.monitors)
+#define ERTS_P_LT_MONITORS(P)	((P)->common.u.alive.lt_monitors)
 
 #define IS_TRACED(p) \
     (ERTS_TRACER(p) != NIL)
@@ -68,6 +69,7 @@ typedef struct {
 	    struct reg_proc *reg;
 	    ErtsLink *links;
 	    ErtsMonitor *monitors;
+            ErtsMonitor *lt_monitors;
 	} alive;
 
 	/* --- While being released --- */
diff --git a/erts/emulator/beam/erl_rbtree.h b/erts/emulator/beam/erl_rbtree.h
index e59d6900b0..e50abf5cec 100644
--- a/erts/emulator/beam/erl_rbtree.h
+++ b/erts/emulator/beam/erl_rbtree.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  * 
- * Copyright Ericsson AB 2015-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2015-2018. All Rights Reserved.
  * 
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -50,8 +50,14 @@
  * - ERTS_RBT_GET_LEFT(T) - Get left child node.
  * - ERTS_RBT_SET_LEFT(T, L) - Set left child node.
  * - ERTS_RBT_GET_KEY(T) - Get key of node.
- * - ERTS_RBT_IS_LT(KX, KY) - Is key KX less than key KY?
- * - ERTS_RBT_IS_EQ(KX, KY) - Is key KX equal to key KY?
+ * Either:
+ *   - ERTS_RBT_CMP_KEYS(KX, KY) - Compare keys...
+ * or:
+ *   - ERTS_RBT_IS_LT(KX, KY) - Is key KX less than key KY?
+ *   - ERTS_RBT_IS_EQ(KX, KY) - Is key KX equal to key KY?
+ *
+ * If ERTS_RBT_CMP_KEYS is defined ERTS_RBT_IS_LT and
+ * ERTS_RBT_IS_EQ will be redefined using ERTS_RBT_CMP_KEYS
  *
  * Optional defines:
  *
@@ -337,6 +343,15 @@
  *         Should only be used for debuging.
  */
 
+#ifdef ERTS_RBT_CMP_KEYS
+
+#  undef ERTS_RBT_IS_LT
+#  define ERTS_RBT_IS_LT(KX, KY) (ERTS_RBT_CMP_KEYS((KX), (KY)) < 0)
+
+#  undef ERTS_RBT_IS_EQ
+#  define ERTS_RBT_IS_EQ(KX, KY) (ERTS_RBT_CMP_KEYS((KX), (KY)) == 0)
+
+#endif
 
 /*
  * Check that we have all mandatory defines
@@ -396,6 +411,16 @@
 #  error Missing definition of ERTS_RBT_IS_EQ
 #endif
 
+#undef ERTS_RBT_IS_GT__
+#ifdef ERTS_RBT_CMP_KEYS
+#  define ERTS_RBT_IS_GT__(KX, KY) \
+    (ERTS_RBT_CMP_KEYS((KX), (KY)) > 0)
+#else
+#  define ERTS_RBT_IS_GT__(KX, KY) \
+    (!ERTS_RBT_IS_LT((KX), (KY)) && !ERTS_RBT_IS_EQ((KX), (KY)))
+
+#endif
+
 #if defined(ERTS_RBT_HARD_DEBUG) || defined(DEBUG)
 #  ifndef ERTS_RBT_DEBUG
 #    define ERTS_RBT_DEBUG 1
@@ -1007,19 +1032,30 @@ ERTS_RBT_FUNC__(insert_aux__)(ERTS_RBT_T **root, ERTS_RBT_T *n, int lookup)
 	ERTS_RBT_T *p, *x = *root;
 
 	while (1) {
-	    ERTS_RBT_KEY_T kx;
+	    ERTS_RBT_KEY_T kx = ERTS_RBT_GET_KEY(x);
 	    ERTS_RBT_T *c;
+            int kres;
+#ifdef ERTS_RBT_CMP_KEYS
+            int kcmp = ERTS_RBT_CMP_KEYS(kn, kx);
+            kres = kcmp == 0;
+#else
+            kres = ERTS_RBT_IS_EQ(kn, kx);
+#endif
 
-	    kx = ERTS_RBT_GET_KEY(x);
-
-	    if (lookup && ERTS_RBT_IS_EQ(kn, kx)) {
+	    if (lookup && kres) {
 
 		ERTS_RBT_HDBG_CHECK_TREE__(*root, NULL);
 
 		return x;
 	    }
 
-	    if (ERTS_RBT_IS_LT(kn, kx)) {
+#ifdef ERTS_RBT_CMP_KEYS
+            kres = kcmp < 0;
+#else
+            kres = ERTS_RBT_IS_LT(kn, kx);
+#endif
+
+	    if (kres) {
 		c = ERTS_RBT_GET_LEFT(x);
 		if (!c) {
 		    ERTS_RBT_SET_PARENT(n, x);
@@ -1075,6 +1111,101 @@ ERTS_RBT_FUNC__(insert)(ERTS_RBT_T **root, ERTS_RBT_T *n)
 
 #endif /* ERTS_RBT_WANT_INSERT */
 
+#ifdef ERTS_RBT_WANT_LOOKUP_CREATE
+static ERTS_INLINE ERTS_RBT_T *
+ERTS_RBT_FUNC__(lookup_create)(ERTS_RBT_T **root,
+                               ERTS_RBT_KEY_T kn,
+                               ERTS_RBT_T *(*create)(ERTS_RBT_KEY_T, void *),
+                               void *arg,
+                               int *created)
+{
+    ERTS_RBT_T *n;
+    ERTS_RBT_HDBG_CHECK_TREE__(*root, NULL);
+
+    if (!*root) {
+        n = (*create)(kn, arg);
+        ERTS_RBT_INIT_EMPTY_TNODE(n);
+        ERTS_RBT_ASSERT(ERTS_RBT_IS_EQ(ERTS_RBT_GET_KEY(n), kn));
+	ERTS_RBT_SET_BLACK(n);
+	*root = n;
+        *created = !0;
+#ifdef ERTS_RBT_UPDATE_ATTACHED_DATA_CHGROOT
+	ERTS_RBT_UPDATE_ATTACHED_DATA_CHGROOT(NULL, n);
+#endif
+    }
+    else {
+	ERTS_RBT_T *p, *x = *root;
+
+	while (1) {
+	    ERTS_RBT_KEY_T kx = ERTS_RBT_GET_KEY(x);
+	    ERTS_RBT_T *c;
+            int kres;
+#ifdef ERTS_RBT_CMP_KEYS
+            int kcmp = ERTS_RBT_CMP_KEYS(kn, kx);
+            kres = kcmp == 0;
+#else
+            kres = ERTS_RBT_IS_EQ(kn, kx);
+#endif
+
+	    if (kres) {
+
+		ERTS_RBT_HDBG_CHECK_TREE__(*root, NULL);
+
+                *created = 0;
+		return x;
+	    }
+
+#ifdef ERTS_RBT_CMP_KEYS
+            kres = kcmp < 0;
+#else
+            kres = ERTS_RBT_IS_LT(kn, kx);
+#endif
+
+	    if (kres) {
+		c = ERTS_RBT_GET_LEFT(x);
+		if (!c) {
+                    n = (*create)(kn, arg);
+                    ERTS_RBT_INIT_EMPTY_TNODE(n);
+                    ERTS_RBT_ASSERT(ERTS_RBT_IS_EQ(ERTS_RBT_GET_KEY(n), kn));
+                    *created = !0;
+		    ERTS_RBT_SET_PARENT(n, x);
+		    ERTS_RBT_SET_LEFT(x, n);
+		    p = x;
+		    break;
+		}
+	    }
+	    else {
+		c = ERTS_RBT_GET_RIGHT(x);
+		if (!c) {
+                    n = (*create)(kn, arg);
+                    ERTS_RBT_INIT_EMPTY_TNODE(n);
+                    ERTS_RBT_ASSERT(ERTS_RBT_IS_EQ(ERTS_RBT_GET_KEY(n), kn));
+                    *created = !0;
+		    ERTS_RBT_SET_PARENT(n, x);
+		    ERTS_RBT_SET_RIGHT(x, n);
+		    p = x;
+		    break;
+		}
+	    }
+
+	    x = c;
+	}
+
+        ERTS_RBT_ASSERT(ERTS_RBT_IS_EQ(ERTS_RBT_GET_KEY(n), kn));
+	ERTS_RBT_ASSERT(p);
+
+	ERTS_RBT_SET_RED(n);
+	if (ERTS_RBT_IS_RED(p))
+	    ERTS_RBT_FUNC__(insert_fixup__)(root, n);
+    }
+
+    ERTS_RBT_HDBG_CHECK_TREE__(*root, n);
+
+    return n;
+}
+
+#endif /* ERTS_RBT_WANT_LOOKUP_CREATE */
+
 #ifdef ERTS_RBT_WANT_LOOKUP
 
 static ERTS_RBT_API_INLINE__ ERTS_RBT_T *
@@ -1088,11 +1219,24 @@ ERTS_RBT_FUNC__(lookup)(ERTS_RBT_T *root, ERTS_RBT_KEY_T key)
     while (1) {
 	ERTS_RBT_KEY_T kx = ERTS_RBT_GET_KEY(x);
 	ERTS_RBT_T *c;
+        int kres;
+#ifdef ERTS_RBT_CMP_KEYS
+        int kcmp = ERTS_RBT_CMP_KEYS(key, kx);
+        kres = kcmp == 0;
+#else
+        kres = ERTS_RBT_IS_EQ(key, kx);
+#endif
 
-	if (ERTS_RBT_IS_EQ(key, kx))
+	if (kres)
 	    return x;
 
-	if (ERTS_RBT_IS_LT(key, kx)) {
+#ifdef ERTS_RBT_CMP_KEYS
+        kres = kcmp < 0;
+#else
+        kres = ERTS_RBT_IS_LT(key, kx);
+#endif
+
+	if (kres) {
 	    c = ERTS_RBT_GET_LEFT(x);
 	    if (!c)
 		return NULL;
@@ -1426,14 +1570,14 @@ ERTS_RBT_FUNC__(foreach_large)(ERTS_RBT_T *root,
 
 #ifdef ERTS_RBT_WANT_FOREACH_YIELDING
 
-static ERTS_RBT_API_INLINE__ void
+static ERTS_RBT_API_INLINE__ int
 ERTS_RBT_FUNC__(foreach_yielding)(ERTS_RBT_T *root,
 				  void (*op)(ERTS_RBT_T *, void *),
 				  void *arg,
 				  ERTS_RBT_YIELD_STATE_T__ *ystate,
 				  Sint ylimit)
 {
-    (void) ERTS_RBT_FUNC__(foreach_unordered__)(*root, 0, op, arg,
+    return ERTS_RBT_FUNC__(foreach_unordered__)(&root, 0, op, arg,
 						1, ystate, ylimit);
 }
 
@@ -1630,8 +1774,7 @@ ERTS_RBT_FUNC__(hdbg_check_tree)(ERTS_RBT_T *root, ERTS_RBT_T *n)
 		kx = ERTS_RBT_GET_KEY(x);
 		kc = ERTS_RBT_GET_KEY(c);
 
-		ERTS_RBT_ASSERT(ERTS_RBT_IS_LT(kc, kx)
-				|| ERTS_RBT_IS_EQ(kc, kx));
+                ERTS_RBT_ASSERT(!ERTS_RBT_IS_GT__(kc, kx));
 
 		x = c;
 	    }
@@ -1649,8 +1792,8 @@ ERTS_RBT_FUNC__(hdbg_check_tree)(ERTS_RBT_T *root, ERTS_RBT_T *n)
 	    kx = ERTS_RBT_GET_KEY(x);
 	    kc = ERTS_RBT_GET_KEY(c);
 
-	    ERTS_RBT_ASSERT(ERTS_RBT_IS_LT(kx, kc)
-			    || ERTS_RBT_IS_EQ(kx, kc));
+            ERTS_RBT_ASSERT(!ERTS_RBT_IS_GT__(kx, kc));
+
 	    x = c;
 	}
 
@@ -1672,8 +1815,8 @@ ERTS_RBT_FUNC__(hdbg_check_tree)(ERTS_RBT_T *root, ERTS_RBT_T *n)
 		    kx = ERTS_RBT_GET_KEY(x);
 		    kc = ERTS_RBT_GET_KEY(c);
 
-		    ERTS_RBT_ASSERT(ERTS_RBT_IS_LT(kx, kc)
-				    || ERTS_RBT_IS_EQ(kx, kc));
+                    ERTS_RBT_ASSERT(!ERTS_RBT_IS_GT__(kx, kc));
+
 		    /* Go down tree of x's sibling... */
 		    x = c;
 		    break;
@@ -1707,6 +1850,7 @@ ERTS_RBT_FUNC__(hdbg_check_tree)(ERTS_RBT_T *root, ERTS_RBT_T *n)
 #undef ERTS_RBT_NEED_FOREACH_ORDERED__
 #undef ERTS_RBT_NEED_HDBG_CHECK_TREE__
 #undef ERTS_RBT_HDBG_CHECK_TREE__
+#undef ERTS_RBT_IS_GT__
 
 #ifdef ERTS_RBT_UNDEF
 #  undef ERTS_RBT_PREFIX
@@ -1727,6 +1871,7 @@ ERTS_RBT_FUNC__(hdbg_check_tree)(ERTS_RBT_T *root, ERTS_RBT_T *n)
 #  undef ERTS_RBT_GET_LEFT
 #  undef ERTS_RBT_SET_LEFT
 #  undef ERTS_RBT_GET_KEY
+#  undef ERTS_RBT_CMP_KEYS
 #  undef ERTS_RBT_IS_LT
 #  undef ERTS_RBT_IS_EQ
 #  undef ERTS_RBT_UNDEF
diff --git a/erts/emulator/beam/erl_term.h b/erts/emulator/beam/erl_term.h
index 3dd1c2555c..18483fca35 100644
--- a/erts/emulator/beam/erl_term.h
+++ b/erts/emulator/beam/erl_term.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2000-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2000-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -345,6 +345,9 @@ _ET_DECLARE_CHECKED(Uint,thing_subtag,Eterm)
  *
  * To help find code which makes unwarranted assumptions about zero,
  * we now use a non-zero bit-pattern in debug mode.
+ *
+ * In order to be able to differentiata against values, the non-value
+ * needs to be tagged as a header of some sort.
  */
 #if ET_DEBUG
 # ifdef HIPE
@@ -355,7 +358,7 @@ _ET_DECLARE_CHECKED(Uint,thing_subtag,Eterm)
 #  define THE_NON_VALUE	_make_header(0,_TAG_HEADER_FLOAT)
 # endif
 #else
-#define THE_NON_VALUE	(0)
+#define THE_NON_VALUE	(TAG_PRIMARY_HEADER)
 #endif
 #define is_non_value(x)	((x) == THE_NON_VALUE)
 #define is_value(x)	((x) != THE_NON_VALUE)
diff --git a/erts/emulator/beam/erl_time.h b/erts/emulator/beam/erl_time.h
index 65211e4e6f..968f21fd51 100644
--- a/erts/emulator/beam/erl_time.h
+++ b/erts/emulator/beam/erl_time.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  * 
- * Copyright Ericsson AB 2006-2017. All Rights Reserved.
+ * Copyright Ericsson AB 2006-2018. All Rights Reserved.
  * 
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,6 +21,8 @@
 #ifndef ERL_TIME_H__
 #define ERL_TIME_H__
 
+#include "erl_monitor_link.h"
+
 #if 0
 #  define ERTS_TW_DEBUG
 #endif
@@ -79,8 +81,8 @@ typedef ErtsMonotonicTime * ErtsNextTimeoutRef;
 extern SysTimeval erts_first_emu_time;
 
 
-void erts_monitor_time_offset(Eterm id, Eterm ref);
-int erts_demonitor_time_offset(Eterm ref);
+void erts_monitor_time_offset(ErtsMonitor *mon);
+void erts_demonitor_time_offset(ErtsMonitor *mon);
 
 int erts_init_time_sup(int, ErtsTimeWarpMode);
 void erts_late_init_time_sup(void);
diff --git a/erts/emulator/beam/erl_time_sup.c b/erts/emulator/beam/erl_time_sup.c
index 8cbdf9fa0f..e5bb3cc15f 100644
--- a/erts/emulator/beam/erl_time_sup.c
+++ b/erts/emulator/beam/erl_time_sup.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1999-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1999-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -35,6 +35,7 @@
 #include "erl_time.h"
 #include "erl_driver.h"
 #include "erl_nif.h"
+#include "erl_proc_sig_queue.h"
  
 static erts_mtx_t erts_get_time_mtx;
 
@@ -1870,36 +1871,33 @@ void erts_get_now_cpu(Uint* megasec, Uint* sec, Uint* microsec) {
 #include "big.h"
 
 void
-erts_monitor_time_offset(Eterm id, Eterm ref)
+erts_monitor_time_offset(ErtsMonitor *mon)
 {
     erts_mtx_lock(&erts_get_time_mtx);
-    erts_add_monitor(&time_offset_monitors, MON_TIME_OFFSET, ref, id, NIL);
+    erts_monitor_list_insert(&time_offset_monitors, mon);
     no_time_offset_monitors++;
     erts_mtx_unlock(&erts_get_time_mtx);
 }
 
-int
-erts_demonitor_time_offset(Eterm ref)
+void
+erts_demonitor_time_offset(ErtsMonitor *mon)
 {
-    int res;
-    ErtsMonitor *mon;
-    ASSERT(is_internal_ref(ref));
+    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
+    ASSERT(erts_monitor_is_origin(mon));
+    ASSERT(mon->type == ERTS_MON_TYPE_TIME_OFFSET);
+
     erts_mtx_lock(&erts_get_time_mtx);
-    if (is_internal_ordinary_ref(ref))
-        mon = erts_remove_monitor(&time_offset_monitors, ref);
-    else
-        mon = NULL;
-    if (!mon)
-	res = 0;
-    else {
-	ASSERT(no_time_offset_monitors > 0);
-	no_time_offset_monitors--;
-	res = 1;
-    }
+
+    ASSERT(erts_monitor_is_in_table(&mdp->target));
+
+    erts_monitor_list_delete(&time_offset_monitors, &mdp->target);
+
+    ASSERT(no_time_offset_monitors > 0);
+    no_time_offset_monitors--;
+
     erts_mtx_unlock(&erts_get_time_mtx);
-    if (res)
-	erts_destroy_monitor(mon);
-    return res;
+
+    erts_monitor_release_both(mdp);
 }
 
 typedef struct {
@@ -1917,17 +1915,19 @@ static void
 save_time_offset_monitor(ErtsMonitor *mon, void *vcntxt)
 {
     ErtsTimeOffsetMonitorContext *cntxt;
+    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
     Eterm *from_hp, *to_hp;
     Uint mix;
     int hix;
 
     cntxt = (ErtsTimeOffsetMonitorContext *) vcntxt;
     mix = (cntxt->ix)++;
-    cntxt->to_mon_info[mix].pid = mon->u.pid;
+    ASSERT(is_internal_pid(mon->other.item));
+    cntxt->to_mon_info[mix].pid = mon->other.item;
     to_hp = &cntxt->to_mon_info[mix].heap[0];
 
-    ASSERT(is_internal_ordinary_ref(mon->ref));
-    from_hp = internal_ref_val(mon->ref);
+    ASSERT(is_internal_ordinary_ref(mdp->ref));
+    from_hp = internal_ref_val(mdp->ref);
     ASSERT(thing_arityval(*from_hp) + 1 == ERTS_REF_THING_SIZE);
 
     for (hix = 0; hix < ERTS_REF_THING_SIZE; hix++)
@@ -1972,9 +1972,9 @@ send_time_offset_changed_notifications(void *new_offsetp)
 	cntxt.ix = 0;
 	cntxt.to_mon_info = to_mon_info;
 
-	erts_doforall_monitors(time_offset_monitors,
-			       save_time_offset_monitor,
-			       &cntxt);
+        erts_monitor_list_foreach(time_offset_monitors,
+                                  save_time_offset_monitor,
+                                  &cntxt);
 
 	ASSERT(cntxt.ix == no_monitors);
     }
@@ -2008,26 +2008,14 @@ send_time_offset_changed_notifications(void *new_offsetp)
 	ASSERT(*patch_refp == THE_NON_VALUE);
 
 	for (mix = 0; mix < no_monitors; mix++) {
-	    Process *rp = erts_proc_lookup(to_mon_info[mix].pid);
-	    if (rp) {
-		Eterm ref = to_mon_info[mix].ref;
-		ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK;
-		erts_proc_lock(rp, ERTS_PROC_LOCK_LINK);
-		if (erts_lookup_monitor(ERTS_P_MONITORS(rp), ref)) {
-		    ErtsMessage *mp;
-		    ErlOffHeap *ohp;
-		    Eterm message;
-
-		    mp = erts_alloc_message_heap(rp, &rp_locks,
-						 hsz, &hp, &ohp);
-		    *patch_refp = ref;
-		    ASSERT(hsz == size_object(message_template));
-		    message = copy_struct(message_template, hsz, &hp, ohp);
-		    erts_queue_message(rp, rp_locks, mp, message, am_clock_service);
-		}
-		erts_proc_unlock(rp, rp_locks);
-	    }
-	}
+            *patch_refp = to_mon_info[mix].ref;
+            erts_proc_sig_send_persistent_monitor_msg(ERTS_MON_TYPE_TIME_OFFSET,
+                                                      *patch_refp,
+                                                      am_clock_service,
+                                                      to_mon_info[mix].pid,
+                                                      message_template,
+                                                      hsz);
+        }
 
 	erts_free(ERTS_ALC_T_TMP, tmp);
     }
diff --git a/erts/emulator/beam/external.h b/erts/emulator/beam/external.h
index f9f8abcc27..bbd9b4bad2 100644
--- a/erts/emulator/beam/external.h
+++ b/erts/emulator/beam/external.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1996-2016. All Rights Reserved.
+ * Copyright Ericsson AB 1996-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -83,7 +83,10 @@
 #ifndef ERL_EXTERNAL_H__
 #define ERL_EXTERNAL_H__
 
+#define ERL_NODE_TABLES_BASIC_ONLY
 #include "erl_node_tables.h"
+#undef ERL_NODE_TABLES_BASIC_ONLY
+#include "erl_alloc.h"
 
 #define ERTS_ATOM_CACHE_SIZE 2048
 
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 0f23027752..d853b2e352 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1996-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1996-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -87,9 +87,7 @@ typedef struct
 {
     erts_mtx_t lock;
     ErtsMonitor* root;
-    int pending_failed_fire;
-    int is_dying;
-
+    Uint refc;
     size_t user_data_sz;
 } ErtsResourceMonitors;
 
@@ -116,7 +114,8 @@ extern void erts_pre_nif(struct enif_environment_t*, Process*,
 			 struct erl_module_nif*, Process* tracee);
 extern void erts_post_nif(struct enif_environment_t* env);
 extern void erts_resource_stop(ErtsResource*, ErlNifEvent, int is_direct_call);
-void erts_fire_nif_monitor(ErtsResource*, Eterm pid, Eterm ref);
+void erts_fire_nif_monitor(ErtsMonitor *tmon);
+void erts_nif_demonitored(ErtsResource* resource);
 extern Eterm erts_nif_taints(Process* p);
 extern void erts_print_nif_taints(fmtfn_t to, void* to_arg);
 void erts_unload_nif(struct erl_module_nif* nif);
@@ -886,6 +885,7 @@ void erts_init_trap_export(Export* ep, Eterm m, Eterm f, Uint a,
 			   Eterm (*bif)(Process*, Eterm*, BeamInstr*));
 void erts_init_bif(void);
 Eterm erl_send(Process *p, Eterm to, Eterm msg);
+int erts_set_group_leader(Process *proc, Eterm new_gl);
 
 /* erl_bif_op.c */
 
@@ -908,7 +908,6 @@ extern erts_atomic_t erts_copy_literal_area__;
 #define ERTS_COPY_LITERAL_AREA()					\
     ((ErtsLiteralArea *) erts_atomic_read_nob(&erts_copy_literal_area__))
 extern Process *erts_literal_area_collector;
-extern Process *erts_dirty_process_code_checker;
 
 extern Process *erts_code_purger;
 
@@ -1072,7 +1071,7 @@ void erts_move_multi_frags(Eterm** hpp, ErlOffHeap*, ErlHeapFragment* first,
 			   Eterm* refs, unsigned nrefs, int literals);
 
 /* Utilities */
-extern void erts_delete_nodes_monitors(Process *, ErtsProcLocks);
+void erts_monitor_nodes_delete(ErtsMonitor *);
 extern Eterm erts_monitor_nodes(Process *, Eterm, Eterm);
 extern Eterm erts_processes_monitoring_nodes(Process *);
 extern int erts_do_net_exits(DistEntry*, Eterm);
diff --git a/erts/emulator/beam/io.c b/erts/emulator/beam/io.c
index e4a5f2b6b6..b2afdc6bf2 100644
--- a/erts/emulator/beam/io.c
+++ b/erts/emulator/beam/io.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1996-2017. All Rights Reserved.
+ * Copyright Ericsson AB 1996-2018. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -53,6 +53,7 @@
 #include "erl_hl_timer.h"
 #include "erl_time.h"
 #include "erl_io_queue.h"
+#include "erl_proc_sig_queue.h"
 
 extern ErlDrvEntry fd_driver_entry;
 extern ErlDrvEntry vanilla_driver_entry;
@@ -366,6 +367,7 @@ static Port *create_port(char *name,
     prt->drv_ptr = driver;
     ERTS_P_LINKS(prt) = NULL;
     ERTS_P_MONITORS(prt) = NULL;
+    ERTS_P_LT_MONITORS(prt) = NULL;
     prt->linebuf = NULL;
     prt->suspended = NULL;
     erts_init_port_data(prt);
@@ -748,8 +750,8 @@ driver_create_port(ErlDrvPort creator_port_ix, /* Creating port */
     Port *creator_port;
     Port* port;
     erts_driver_t *driver;
-    Process *rp;
     erts_mtx_t *driver_lock = NULL;
+    ErtsLinkData *ldp;
 
     ERTS_CHK_NO_PROC_LOCKS;
 
@@ -761,17 +763,13 @@ driver_create_port(ErlDrvPort creator_port_ix, /* Creating port */
     if (creator_port == ERTS_INVALID_ERL_DRV_PORT)
 	return ERTS_INVALID_ERL_DRV_PORT;
 
-    rp = erts_proc_lookup(pid);
-    if (!rp)
-	return ERTS_INVALID_ERL_DRV_PORT;
-
     ERTS_LC_ASSERT(erts_lc_is_port_locked(creator_port));
 
     driver = creator_port->drv_ptr;
     erts_rwmtx_rlock(&erts_driver_list_lock);
     if (!erts_ddll_driver_ok(driver->handle)) {
 	erts_rwmtx_runlock(&erts_driver_list_lock);
-	return ERTS_INVALID_ERL_DRV_PORT;
+        return ERTS_INVALID_ERL_DRV_PORT;
     }
 
     if (driver->handle != NULL) {
@@ -799,9 +797,15 @@ driver_create_port(ErlDrvPort creator_port_ix, /* Creating port */
     }
     ERTS_LC_ASSERT(erts_lc_is_port_locked(port));
 
-    erts_proc_lock(rp, ERTS_PROC_LOCK_LINK);
-    if (ERTS_PROC_IS_EXITING(rp)) {
-	erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
+    ldp = erts_link_create(ERTS_LNK_TYPE_PORT,
+                           port->common.id, pid);
+    ASSERT(ldp->a.other.item == pid);
+    ASSERT(ldp->b.other.item == port->common.id);
+    erts_link_tree_insert(&ERTS_P_LINKS(port), &ldp->a);
+
+    if (!erts_proc_sig_send_link(NULL, pid, &ldp->b)) {
+        erts_link_tree_delete(&ERTS_P_LINKS(port), &ldp->a);
+        erts_link_release_both(ldp);
 	if (driver->handle) {
 	    erts_rwmtx_rlock(&erts_driver_list_lock);
 	    erts_ddll_decrement_port_count(driver->handle);
@@ -812,10 +816,6 @@ driver_create_port(ErlDrvPort creator_port_ix, /* Creating port */
 	return ERTS_INVALID_ERL_DRV_PORT;
     }
 
-    erts_add_link(&ERTS_P_LINKS(port), LINK_PID, pid);
-    erts_add_link(&ERTS_P_LINKS(rp), LINK_PID, port->common.id);
-    erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-
     if (!driver_lock) {
 	ErtsXPortsList *xplp = xports_list_alloc();
 	xplp->port = port;
@@ -1167,21 +1167,10 @@ erts_schedule_proc2port_signal(Process *c_p,
 	 *       otherwise, next receive will *not* work
 	 *       as expected!
 	 */
-	erts_proc_lock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
-
-	if (ERTS_PROC_PENDING_EXIT(c_p)) {
-	    /* need to exit caller instead */
-	    erts_proc_unlock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
-	    KILL_CATCHES(c_p);
-	    c_p->freason = EXC_EXIT;
-	    return ERTS_PORT_OP_CALLER_EXIT;
-	}
-
-	ERTS_MSGQ_MV_INQ2PRIVQ(c_p);
-	c_p->msg.save = c_p->msg.last;
 
-        erts_proc_unlock(c_p, (ERTS_PROC_LOCKS_MSG_RECEIVE
-                                   | ERTS_PROC_LOCK_MAIN));
+        ERTS_RECV_MARK_SAVE(c_p);
+        ERTS_RECV_MARK_SET(c_p);
+        erts_proc_unlock(c_p, ERTS_PROC_LOCK_MAIN);
     }
 
 
@@ -1239,29 +1228,12 @@ erts_schedule_port2port_signal(Eterm port_num, ErtsProc2PortSigData *sigdp,
 
 static ERTS_INLINE void
 send_badsig(Port *prt) {
-    ErtsProcLocks rp_locks = ERTS_PROC_LOCKS_XSIG_SEND;
-    Process* rp;
     Eterm connected = ERTS_PORT_GET_CONNECTED(prt);
     ERTS_CHK_NO_PROC_LOCKS;
     ERTS_LC_ASSERT(erts_get_scheduler_id());
-
     ASSERT(is_internal_pid(connected));
-
-    rp = erts_proc_lookup_raw(connected);
-    if (rp) {
-	erts_proc_lock(rp, rp_locks);
-	if (!ERTS_PROC_IS_EXITING(rp))
-	    (void) erts_send_exit_signal(NULL,
-					 prt->common.id,
-					 rp,
-					 &rp_locks, 
-					 am_badsig,
-					 NIL,
-					 NULL,
-					 0);
-	if (rp_locks)
-	    erts_proc_unlock(rp, rp_locks);
-    } /* exit sent */
+    erts_proc_sig_send_exit(NULL, prt->common.id, connected,
+                            am_badsig, NIL, 0);
 } /* send_badsig */
 
 static void
@@ -2194,11 +2166,11 @@ call_deliver_port_exit(int bang_op,
     }
 
     if (broken_link) {
-	ErtsLink *lnk = erts_remove_link(&ERTS_P_LINKS(prt), from);
-	if (lnk)
-	    erts_destroy_link(lnk);
-	else
+	ErtsLink *lnk = erts_link_tree_lookup(ERTS_P_LINKS(prt), from);
+	if (!lnk) 
 	    return ERTS_PORT_OP_DROPPED;
+        erts_link_tree_delete(&ERTS_P_LINKS(prt), lnk);
+        erts_link_release(lnk);
     }
 
     if (IS_TRACED_FL(prt, F_TRACE_RECEIVE))
@@ -2367,27 +2339,30 @@ set_port_connected(int bang_op,
 #endif
     }
     else { /* Port BIF operation */
-	Process *rp = erts_proc_lookup_raw(connect);
-	if (!rp)
-	    return ERTS_PORT_OP_DROPPED;
-	erts_proc_lock(rp, ERTS_PROC_LOCK_LINK);
-	if (ERTS_PROC_IS_EXITING(rp)) {
-	    erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-	    return ERTS_PORT_OP_DROPPED;
-	}
-
-	erts_add_link(&ERTS_P_LINKS(rp), LINK_PID, prt->common.id);
-	erts_add_link(&ERTS_P_LINKS(prt), LINK_PID, connect);
-
-        if (IS_TRACED_FL(rp, F_TRACE_PROCS))
-            trace_proc(NULL, 0, rp, am_getting_linked, prt->common.id);
+        int created;
+        ErtsLink *lnk;
+
+        if (is_not_internal_pid(connect))
+            return ERTS_PORT_OP_DROPPED;
+
+        lnk = erts_link_tree_lookup_create(&ERTS_P_LINKS(prt), &created,
+                                           ERTS_LNK_TYPE_PORT, prt->common.id,
+                                           connect);
+        if (created) {
+            ErtsLinkData *ldp;
+            ErtsLink *olnk = erts_link_to_other(lnk, &ldp);
+            ASSERT(olnk->other.item == prt->common.id);
+            if (!erts_proc_sig_send_link(NULL, connect, olnk)) {
+                erts_link_tree_delete(&ERTS_P_LINKS(prt), lnk);
+                erts_link_release_both(ldp);
+                return ERTS_PORT_OP_DROPPED;
+            }
+            if (IS_TRACED_FL(prt, F_TRACE_PORTS))
+                trace_port(prt, am_getting_linked, connect);
+        }
 
 	ERTS_PORT_SET_CONNECTED(prt, connect);
 
-	erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-
-        if (IS_TRACED_FL(prt, F_TRACE_PORTS))
-            trace_port(prt, am_getting_linked, connect);
         if (IS_TRACED_FL(prt, F_TRACE_RECEIVE))
             trace_port_receive(prt, from, am_connect, connect);
         if (IS_TRACED_FL(prt, F_TRACE_SEND)) {
@@ -2494,13 +2469,24 @@ erts_port_connect(Process *c_p,
 }
 
 static void
-port_unlink(Port *prt, Eterm from)
+port_unlink(Port *prt, ErtsLink *lnk)
 {
-    ErtsLink *lnk = erts_remove_link(&ERTS_P_LINKS(prt), from);
-    if (lnk) {
+    ErtsLinkData *ldp;
+    ErtsLink *dlnk, *llnk;
+
+    llnk = erts_link_to_other(lnk, &ldp);
+    dlnk = erts_link_tree_key_delete(&ERTS_P_LINKS(prt), llnk);
+    if (!dlnk)
+        erts_link_release(lnk);
+    else {
         if (IS_TRACED_FL(prt, F_TRACE_PORTS))
-            trace_port(prt, am_getting_unlinked, from);
-	erts_destroy_link(lnk);
+            trace_port(prt, am_getting_unlinked, llnk->other.item);
+        if (dlnk == llnk)
+            erts_link_release_both(ldp);
+        else {
+            erts_link_release(lnk);
+            erts_link_release(dlnk);
+        }
     }
 }
 
@@ -2508,14 +2494,14 @@ static int
 port_sig_unlink(Port *prt, erts_aint32_t state, int op, ErtsProc2PortSigData *sigdp)
 {
     if (op == ERTS_PROC2PORT_SIG_EXEC)
-	port_unlink(prt, sigdp->u.unlink.from);
+	port_unlink(prt, sigdp->u.unlink.lnk);
     if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY)
 	port_sched_op_reply(sigdp->caller, sigdp->ref, am_true, prt);
     return ERTS_PORT_REDS_UNLINK;
 }
 
 ErtsPortOpResult
-erts_port_unlink(Process *c_p, Port *prt, Eterm from, Eterm *refp)
+erts_port_unlink(Process *c_p, Port *prt, ErtsLink *lnk, Eterm *refp)
 {
     ErtsProc2PortSigData *sigdp;
     ErtsTryImmDrvCallState try_call_state
@@ -2528,7 +2514,7 @@ erts_port_unlink(Process *c_p, Port *prt, Eterm from, Eterm *refp)
 
     switch (try_imm_drv_call(&try_call_state)) {
     case ERTS_TRY_IMM_DRV_CALL_OK:
-	port_unlink(prt, from);
+	port_unlink(prt, lnk);
 	finalize_imm_drv_call(&try_call_state);
 	BUMP_REDS(c_p, ERTS_PORT_REDS_UNLINK);
 	return ERTS_PORT_OP_DONE;
@@ -2541,11 +2527,12 @@ erts_port_unlink(Process *c_p, Port *prt, Eterm from, Eterm *refp)
 
     sigdp = erts_port_task_alloc_p2p_sig_data();
     sigdp->flags = ERTS_P2P_SIG_TYPE_UNLINK;
-    sigdp->u.unlink.from = from;
-    
+    sigdp->u.unlink.port_id = prt->common.id;
+    sigdp->u.unlink.lnk = lnk;
+
     return erts_schedule_proc2port_signal(c_p,
 					  prt,
-					  c_p ? c_p->common.id : from,
+					  c_p->common.id,
 					  refp,
 					  sigdp,
 					  0,
@@ -2554,45 +2541,24 @@ erts_port_unlink(Process *c_p, Port *prt, Eterm from, Eterm *refp)
 }
 
 static void
-port_link_failure(Eterm port_id, Eterm linker)
+port_link_failure(Eterm port_id, ErtsLink *lnk)
 {
-    Process *rp;
-    ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCKS_XSIG_SEND;
-    ASSERT(is_internal_pid(linker));
-    rp = erts_pid2proc(NULL, 0, linker, rp_locks);
-    if (rp) {
-	ErtsLink *rlnk = erts_remove_link(&ERTS_P_LINKS(rp), port_id);
-	if (rlnk) {
-	    int xres = erts_send_exit_signal(NULL,
-					     port_id,
-					     rp,
-					     &rp_locks, 
-					     am_noproc,
-					     NIL,
-					     NULL,
-					     0);
-	    if (xres >= 0) {
-		/* We didn't exit the process and it is traced */
-		if (IS_TRACED_FL(rp, F_TRACE_PROCS))
-		    trace_proc(NULL, 0, rp, am_getting_unlinked, port_id);
-	    }
-	    if (rp_locks)
-		erts_proc_unlock(rp, rp_locks);
-	}
-    }
+    erts_proc_sig_send_link_exit(NULL, port_id, lnk, am_noproc, NIL);
 }
 
 static void
-port_link(Port *prt, erts_aint32_t state, Eterm to)
+port_link(Port *prt, erts_aint32_t state, ErtsLink *lnk)
 {
-    if (IS_TRACED_FL(prt, F_TRACE_PORTS))
-        trace_port(prt, am_getting_linked, to);
-    if (!(state & ERTS_PORT_SFLGS_INVALID_LOOKUP)) {
-	erts_add_link(&ERTS_P_LINKS(prt), LINK_PID, to);
-    } else {
-	port_link_failure(prt->common.id, to);
-        if (IS_TRACED_FL(prt, F_TRACE_PORTS))
-            trace_port(prt, am_unlink, to);
+    if (state & ERTS_PORT_SFLGS_INVALID_LOOKUP)
+	port_link_failure(prt->common.id, lnk);
+    else {
+        ErtsLink *rlnk;
+        rlnk = erts_link_tree_insert_addr_replace(&ERTS_P_LINKS(prt),
+                                                  lnk);
+        if (rlnk)
+            erts_link_release(rlnk);
+        else if (IS_TRACED_FL(prt, F_TRACE_PORTS))
+            trace_port(prt, am_getting_linked, lnk->other.item);
     }
 }
 
@@ -2600,17 +2566,16 @@ static int
 port_sig_link(Port *prt, erts_aint32_t state, int op, ErtsProc2PortSigData *sigdp)
 {
     if (op == ERTS_PROC2PORT_SIG_EXEC)
-	port_link(prt, state, sigdp->u.link.to);
-    else {
-	port_link_failure(sigdp->u.link.port, sigdp->u.link.to);
-    }
+	port_link(prt, state, sigdp->u.link.lnk);
+    else
+	port_link_failure(sigdp->u.link.port_id, sigdp->u.link.lnk);
     if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY)
 	port_sched_op_reply(sigdp->caller, sigdp->ref, am_true, prt);
     return ERTS_PORT_REDS_LINK;
 }
 
 ErtsPortOpResult
-erts_port_link(Process *c_p, Port *prt, Eterm to, Eterm *refp)
+erts_port_link(Process *c_p, Port *prt, ErtsLink *lnk, Eterm *refp)
 {
     ErtsProc2PortSigData *sigdp;
     ErtsTryImmDrvCallState try_call_state
@@ -2623,7 +2588,7 @@ erts_port_link(Process *c_p, Port *prt, Eterm to, Eterm *refp)
 
     switch (try_imm_drv_call(&try_call_state)) {
     case ERTS_TRY_IMM_DRV_CALL_OK:
-	port_link(prt, try_call_state.state, to);
+	port_link(prt, try_call_state.state, lnk);
 	finalize_imm_drv_call(&try_call_state);
 	BUMP_REDS(c_p, ERTS_PORT_REDS_LINK);
 	return ERTS_PORT_OP_DONE;
@@ -2636,12 +2601,12 @@ erts_port_link(Process *c_p, Port *prt, Eterm to, Eterm *refp)
 
     sigdp = erts_port_task_alloc_p2p_sig_data();
     sigdp->flags = ERTS_P2P_SIG_TYPE_LINK;
-    sigdp->u.link.port = prt->common.id;
-    sigdp->u.link.to = to;
+    sigdp->u.link.port_id = prt->common.id;
+    sigdp->u.link.lnk = lnk;
     
     return erts_schedule_proc2port_signal(c_p,
 					  prt,
-					  c_p ? c_p->common.id : to,
+					  c_p->common.id,
 					  refp,
 					  sigdp,
 					  0,
@@ -2650,51 +2615,23 @@ erts_port_link(Process *c_p, Port *prt, Eterm to, Eterm *refp)
 }
 
 static void
-port_monitor_failure(Eterm port_id, Eterm origin, Eterm ref_DOWN)
+port_monitor_failure(Eterm port_id, ErtsMonitor *mon)
 {
-    Process       *origin_p;
-    ErtsProcLocks p_locks = ERTS_PROC_LOCK_LINK;
-    ASSERT(is_internal_pid(origin));
-
-    origin_p = erts_pid2proc(NULL, 0, origin, p_locks);
-    if (! origin_p) { return; }
-
-    /* Send the DOWN message immediately. Ref is made on the fly because
-     * caller has never seen it yet. */
-    erts_queue_monitor_message(origin_p, &p_locks, ref_DOWN,
-                               am_port, port_id, am_noproc);
-    erts_proc_unlock(origin_p, p_locks);
+    erts_proc_sig_send_monitor_down(mon, am_noproc);
 }
 
 /* Origin wants to monitor port Prt. State contains possible error, which has
  * happened just before. Name is either NIL or an atom, if user monitors
  * a port by name. Ref is premade reference that will be returned to user */
 static void
-port_monitor(Port *prt, erts_aint32_t state, Eterm origin,
-             Eterm name, Eterm ref)
+port_monitor(Port *prt, erts_aint32_t state, ErtsMonitor *mon)
 {
-    Eterm name_or_nil = is_atom(name) ? name : NIL;
-
-    ASSERT(is_pid(origin));
-    ASSERT(is_atom(name) || is_port(name) || name == NIL);
-    ASSERT(is_internal_ordinary_ref(ref));
-
-    if (!(state & ERTS_PORT_SFLGS_INVALID_LOOKUP)) {
-        ErtsProcLocks p_locks = ERTS_PROC_LOCK_LINK;
-
-        Process *origin_p = erts_pid2proc(NULL, 0, origin, p_locks);
-        if (! origin_p) {
-            goto failure;
-        }
-        erts_add_monitor(&ERTS_P_MONITORS(origin_p), MON_ORIGIN, ref,
-                         prt->common.id, name_or_nil);
-        erts_add_monitor(&ERTS_P_MONITORS(prt), MON_TARGET, ref,
-                         origin, name_or_nil);
-
-        erts_proc_unlock(origin_p, p_locks);
-    } else {
-failure:
-        port_monitor_failure(prt->common.id, origin, ref);
+    ASSERT(prt);
+    if (state & ERTS_PORT_SFLGS_INVALID_LOOKUP)
+        port_monitor_failure(prt->common.id, mon);
+    else {
+        ASSERT(erts_monitor_is_target(mon));
+        erts_monitor_list_insert(&ERTS_P_LT_MONITORS(prt), mon);
     }
 }
 
@@ -2702,24 +2639,11 @@ static int
 port_sig_monitor(Port *prt, erts_aint32_t state, int op,
                  ErtsProc2PortSigData *sigdp)
 {
-    Eterm hp[ERTS_REF_THING_SIZE];
-    Eterm ref = make_internal_ref(&hp);
-    write_ref_thing(hp, sigdp->ref[0], sigdp->ref[1], sigdp->ref[2]);
-
-    if (op == ERTS_PROC2PORT_SIG_EXEC) {
-        /* erts_add_monitor call inside port_monitor will copy ref from hp */
-        port_monitor(prt, state,
-                     sigdp->u.monitor.origin,
-                     sigdp->u.monitor.name,
-                     ref);
-    } else {
-        port_monitor_failure(sigdp->u.monitor.name,
-                             sigdp->u.monitor.origin,
-                             ref);
-    }
-    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY) {
-        port_sched_op_reply(sigdp->caller, sigdp->ref, am_true, prt);
-    }
+    if (op == ERTS_PROC2PORT_SIG_EXEC)
+        port_monitor(prt, state, sigdp->u.monitor.mon);
+    else
+        port_monitor_failure(sigdp->u.monitor.port_id,
+                             sigdp->u.monitor.mon);
     return ERTS_PORT_REDS_MONITOR;
 }
 
@@ -2727,95 +2651,63 @@ port_sig_monitor(Port *prt, erts_aint32_t state, int op,
  * a reference (ref may be rewritten to be used to serve additionally as a
  * signal id). Name is atom if user monitors port by name or NIL */
 ErtsPortOpResult
-erts_port_monitor(Process *origin, Port *port, Eterm name, Eterm *refp)
+erts_port_monitor(Process *c_p, Port *port, ErtsMonitor *mon)
 {
     ErtsProc2PortSigData *sigdp;
     ErtsTryImmDrvCallState try_call_state
         = ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
-                origin, port, ERTS_PORT_SFLGS_INVALID_LOOKUP,
+                c_p,
+                port,
+                ERTS_PORT_SFLGS_INVALID_LOOKUP,
                 0,
-                0, /* trap_ref is always set so !trap_ref always is false */
+                !0,
                 am_monitor);
 
-    ASSERT(origin);
+    ASSERT(c_p);
     ASSERT(port);
-    ASSERT(is_atom(name) || is_port(name));
-    ASSERT(refp);
+    ASSERT(mon);
 
     switch (try_imm_drv_call(&try_call_state)) {
     case ERTS_TRY_IMM_DRV_CALL_OK:
-        port_monitor(port, try_call_state.state, origin->common.id, name, *refp);
+        port_monitor(port, try_call_state.state, mon);
         finalize_imm_drv_call(&try_call_state);
-        BUMP_REDS(origin, ERTS_PORT_REDS_MONITOR);
+        BUMP_REDS(c_p, ERTS_PORT_REDS_MONITOR);
         return ERTS_PORT_OP_DONE;
     case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
-        return ERTS_PORT_OP_BADARG;
+        return ERTS_PORT_OP_DROPPED;
     default:
         break; /* Schedule call instead... */
     }
 
     sigdp = erts_port_task_alloc_p2p_sig_data();
     sigdp->flags = ERTS_P2P_SIG_TYPE_MONITOR;
-    sigdp->u.monitor.origin = origin->common.id;
-    sigdp->u.monitor.name   = name; /* either named monitor, or port id */
+    sigdp->u.monitor.port_id = port->common.id;
+    sigdp->u.monitor.mon = mon;
 
     /* Ref contents will be initialized here */
-    return erts_schedule_proc2port_signal(origin, port, origin->common.id,
-                                          refp, sigdp, 0, NULL,
+    return erts_schedule_proc2port_signal(c_p,
+                                          port,
+                                          c_p->common.id,
+                                          NULL,
+                                          sigdp,
+                                          0,
+                                          NULL,
                                           port_sig_monitor);
 }
 
-static void
-port_demonitor_failure(Eterm port_id, Eterm origin, Eterm ref)
-{
-    Process       *origin_p;
-    ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK;
-    ErtsMonitor   *mon1;
-    ASSERT(is_internal_pid(origin));
-
-    origin_p = erts_pid2proc(NULL, 0, origin, rp_locks);
-    if (! origin_p) { return; }
-
-    /* do not send any DOWN messages, drop monitors on process */
-    mon1 = erts_remove_monitor(&ERTS_P_MONITORS(origin_p), ref);
-    if (mon1 != NULL) {
-        erts_destroy_monitor(mon1);
-    }
-
-    erts_proc_unlock(origin_p, rp_locks);
-}
-
 /* Origin wants to demonitor port Prt. State contains possible error, which has
  * happened just before. Ref is reference to monitor */
 static void
-port_demonitor(Port *port, erts_aint32_t state, Eterm origin, Eterm ref)
+port_demonitor(Port *port, erts_aint32_t state, ErtsMonitor *mon)
 {
-    ASSERT(port);
-    ASSERT(is_pid(origin));
-    ASSERT(is_internal_ref(ref));
-
-    if (!(state & ERTS_PORT_SFLGS_INVALID_LOOKUP)) {
-        ErtsProcLocks p_locks = ERTS_PROC_LOCK_LINK;
-        Process *origin_p = erts_pid2proc(NULL, 0, origin, p_locks);
-        if (origin_p) {
-            ErtsMonitor *mon1 = erts_remove_monitor(&ERTS_P_MONITORS(origin_p),
-                                                    ref);
-            if (mon1 != NULL) {
-                erts_destroy_monitor(mon1);
-            }
-        }
-        if (1) {
-            ErtsMonitor *mon2 = erts_remove_monitor(&ERTS_P_MONITORS(port),
-                                                    ref);
-            if (mon2 != NULL) {
-                erts_destroy_monitor(mon2);
-            }
-        }
-        if (origin_p) { /* when origin is dying, it won't be found */
-            erts_proc_unlock(origin_p, p_locks);
-        }
-    } else {
-        port_demonitor_failure(port->common.id, origin, ref);
+    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
+    ASSERT(port && mon);
+    ASSERT(erts_monitor_is_origin(mon));
+    if (!erts_monitor_is_in_table(&mdp->target))
+        erts_monitor_release(mon);
+    else {
+        erts_monitor_list_delete(&ERTS_P_LT_MONITORS(port), &mdp->target);
+        erts_monitor_release_both(mdp);
     }
 }
 
@@ -2823,73 +2715,47 @@ static int
 port_sig_demonitor(Port *prt, erts_aint32_t state, int op,
                    ErtsProc2PortSigData *sigdp)
 {
-    Eterm hp[ERTS_REF_THING_SIZE];
-    Eterm ref = make_internal_ref(&hp);
-    write_ref_thing(hp, sigdp->u.demonitor.ref[0],
-                    sigdp->u.demonitor.ref[1],
-                    sigdp->u.demonitor.ref[2]);
-    if (op == ERTS_PROC2PORT_SIG_EXEC) {
-        port_demonitor(prt, state, sigdp->u.demonitor.origin, ref);
-    } else {
-        port_demonitor_failure(sigdp->u.demonitor.name,
-                               sigdp->u.demonitor.origin,
-                               ref);
-    }
-    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY) {
-        port_sched_op_reply(sigdp->caller, sigdp->ref, am_true, prt);
-    }
+    if (op == ERTS_PROC2PORT_SIG_EXEC)
+        port_demonitor(prt, state, sigdp->u.demonitor.mon);
+    else
+        erts_monitor_release(sigdp->u.demonitor.mon);
     return ERTS_PORT_REDS_DEMONITOR;
 }
 
-/* Removes monitor between origin and target, identified by ref.
- * Mode defines normal or relaxed demonitor rules (process is at death) */
-ErtsPortOpResult erts_port_demonitor(Process *origin, ErtsDemonitorMode mode,
-                                     Port *target, Eterm ref,
-                                     Eterm *trap_ref)
+ErtsPortOpResult
+erts_port_demonitor(Process *c_p, Port *prt, ErtsMonitor *mon)
 {
-    Process *c_p = mode == ERTS_PORT_DEMONITOR_NORMAL ? origin : NULL;
     ErtsProc2PortSigData *sigdp;
     ErtsTryImmDrvCallState try_call_state
         = ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
                 c_p,
-                target, ERTS_PORT_SFLGS_INVALID_LOOKUP,
+                prt, ERTS_PORT_SFLGS_INVALID_LOOKUP,
                 0,
-                !trap_ref,
+                !0,
                 am_demonitor);
 
-    ASSERT(origin);
-    ASSERT(target);
-    ASSERT(is_internal_ref(ref));
+    ASSERT(c_p && prt && mon);
 
     switch (try_imm_drv_call(&try_call_state)) {
     case ERTS_TRY_IMM_DRV_CALL_OK:
-        port_demonitor(target, try_call_state.state, origin->common.id, ref);
+        port_demonitor(prt, try_call_state.state, mon);
         finalize_imm_drv_call(&try_call_state);
-        if (mode == ERTS_PORT_DEMONITOR_NORMAL) {
-            BUMP_REDS(origin, ERTS_PORT_REDS_DEMONITOR);
-        }
+        BUMP_REDS(c_p, ERTS_PORT_REDS_DEMONITOR);
         return ERTS_PORT_OP_DONE;
     case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
-        return ERTS_PORT_OP_BADARG;
+        return ERTS_PORT_OP_DROPPED;
     default:
         break; /* Schedule call instead... */
     }
 
     sigdp = erts_port_task_alloc_p2p_sig_data();
     sigdp->flags = ERTS_P2P_SIG_TYPE_DEMONITOR;
-    sigdp->u.demonitor.origin = origin->common.id;
-    sigdp->u.demonitor.name = target->common.id;
-    {
-	Uint32 *nums = internal_ref_numbers(ref);
-        /* Start from 1 skip ref arity */
-        sys_memcpy(sigdp->u.demonitor.ref,
-		   nums,
-                   sizeof(sigdp->u.demonitor.ref));
-    }
+    sigdp->u.demonitor.port_id = prt->common.id;
+    sigdp->u.demonitor.mon = mon;
 
     /* Ref contents will be initialized here */
-    return erts_schedule_proc2port_signal(c_p, target, origin->common.id,
-                                          trap_ref, sigdp, 0, NULL,
+    return erts_schedule_proc2port_signal(c_p, prt, c_p->common.id,
+                                          NULL, sigdp, 0, NULL,
                                           port_sig_demonitor);
 }
 
@@ -2898,11 +2764,13 @@ init_ack_send_reply(Port *port, Eterm resp)
 {
 
     if (!is_internal_port(resp)) {
-        Process *rp = erts_proc_lookup_raw(port->async_open_port->to);
-        erts_proc_lock(rp, ERTS_PROC_LOCK_LINK);
-        erts_remove_link(&ERTS_P_LINKS(port), port->async_open_port->to);
-        erts_remove_link(&ERTS_P_LINKS(rp), port->common.id);
-        erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
+        Eterm proc = port->async_open_port->to;
+        ErtsLink *lnk = erts_link_tree_lookup(ERTS_P_LINKS(port),
+                                              proc);
+        if (lnk) {
+            erts_link_tree_delete(&ERTS_P_LINKS(port), lnk);
+            erts_proc_sig_send_unlink(NULL, lnk);
+        }
     }
     port_sched_op_reply(port->async_open_port->to,
                         port->async_open_port->ref,
@@ -3680,6 +3548,7 @@ terminate_port(Port *prt)
 
     ASSERT(!ERTS_P_LINKS(prt));
     ASSERT(!ERTS_P_MONITORS(prt));
+    ASSERT(!ERTS_P_LT_MONITORS(prt));
 
     /* state may be altered by kill_port() below */
     state = erts_atomic32_read_band_nob(&prt->state,
@@ -3767,146 +3636,25 @@ erts_terminate_port(Port *pp)
     terminate_port(pp);
 }
 
-static void port_fire_one_monitor(ErtsMonitor *mon, void *ctx0);
-static void sweep_one_monitor(ErtsMonitor *mon, void *vpsc)
-{
-    switch (mon->type) {
-    case MON_ORIGIN: {
-        ErtsMonitor *rmon;
-        Process *rp;
-
-        ASSERT(is_internal_pid(mon->u.pid));
-        rp = erts_pid2proc(NULL, 0, mon->u.pid, ERTS_PROC_LOCK_LINK);
-        if (!rp) {
-            goto done;
-        }
-        rmon = erts_remove_monitor(&ERTS_P_MONITORS(rp), mon->ref);
-        erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-        if (rmon == NULL) {
-            goto done;
-        }
-        erts_destroy_monitor(rmon);
-    } break;
-    case MON_TARGET: {
-        port_fire_one_monitor(mon, vpsc); /* forward call */
-    } break;
-    }
- done:
-    erts_destroy_monitor(mon);
-}
-
-
-
 typedef struct {
-    Port *port;
+    Eterm port_id;
     Eterm reason;
-} SweepContext;
+} ErtsPortExitContext;
 
-static void sweep_one_link(ErtsLink *lnk, void *vpsc)
+static void link_port_exit(ErtsLink *lnk, void *vpectxt)
 {
-    SweepContext *psc = vpsc;
-    DistEntry *dep;
-    Process *rp;
-    Eterm port_id = psc->port->common.id;
-
-    ASSERT(lnk->type == LINK_PID);
-
-    if (IS_TRACED_FL(psc->port, F_TRACE_PORTS))
-        trace_port(psc->port, am_unlink, lnk->pid);
-
-    if (is_external_pid(lnk->pid)) {
-	dep = external_pid_dist_entry(lnk->pid);
-	if(dep != erts_this_dist_entry) {
-	    ErtsDistLinkData dld;
-	    ErtsDSigData dsd;
-	    int code;
-	    code = erts_dsig_prepare(&dsd, dep, NULL, 0, ERTS_DSP_NO_LOCK, 0, 0);
-	    switch (code) {
-	    case ERTS_DSIG_PREP_NOT_ALIVE:
-	    case ERTS_DSIG_PREP_NOT_CONNECTED:
-		break;
-	    case ERTS_DSIG_PREP_PENDING:
-	    case ERTS_DSIG_PREP_CONNECTED:
-		erts_remove_dist_link(&dld, port_id, lnk->pid, dep);
-		erts_destroy_dist_link(&dld);
-		code = erts_dsig_send_exit(&dsd, port_id, lnk->pid,
-					   psc->reason);
-		ASSERT(code == ERTS_DSIG_SEND_OK);
-		break;
-	    default:
-		ASSERT(! "Invalid dsig prepare result");
-		break;
-	    }
-	}
-    } else {
-	ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCKS_XSIG_SEND;
-	ASSERT(is_internal_pid(lnk->pid));
-	rp = erts_pid2proc(NULL, 0, lnk->pid, rp_locks);
-	if (rp) {
-	    ErtsLink *rlnk = erts_remove_link(&ERTS_P_LINKS(rp), port_id);
-
-	    if (rlnk) {
-		int xres = erts_send_exit_signal(NULL,
-						 port_id,
-						 rp,
-						 &rp_locks, 
-						 psc->reason,
-						 NIL,
-						 NULL,
-						 0);
-		if (xres >= 0) {
-                    if (rp_locks & ERTS_PROC_LOCKS_XSIG_SEND) {
-                        erts_proc_unlock(rp, ERTS_PROC_LOCKS_XSIG_SEND);
-                        rp_locks &= ~ERTS_PROC_LOCKS_XSIG_SEND;
-                    }
-		    /* We didn't exit the process and it is traced */
-		    if (IS_TRACED_FL(rp, F_TRACE_PROCS))
-			trace_proc(NULL, 0, rp, am_getting_unlinked, port_id);
-		}
-		erts_destroy_link(rlnk);
-	    }
-
-	    erts_proc_unlock(rp, rp_locks);
-	}
-    }
-    erts_destroy_link(lnk);
+    ErtsPortExitContext *pectxt = vpectxt;
+    erts_proc_sig_send_link_exit(NULL, pectxt->port_id,
+                                 lnk, pectxt->reason, NIL);
 }
 
-static void
-port_fire_one_monitor(ErtsMonitor *mon, void *ctx0)
+static void monitor_port_exit(ErtsMonitor *mon, void *vpectxt)
 {
-    Process      *origin;
-    ErtsProcLocks origin_locks;
-
-    if (mon->type != MON_TARGET || ! is_pid(mon->u.pid)) {
-        return;
-    }
-    /*
-     * Proceed here if someone monitors us, we (port) are the target and
-     * origin is some process
-     */
-    origin_locks = ERTS_PROC_LOCKS_MSG_SEND | ERTS_PROC_LOCK_LINK;
-
-    origin = erts_pid2proc(NULL, 0, mon->u.pid, origin_locks);
-    if (origin) {
-        DeclareTmpHeapNoproc(lhp,3);
-        SweepContext    *ctx = (SweepContext *)ctx0;
-        ErtsMonitor     *rmon;
-        Eterm           watched = (is_atom(mon->name)
-                       ? TUPLE2(lhp, mon->name, erts_this_dist_entry->sysname)
-                       : ctx->port->common.id);
-
-        erts_queue_monitor_message(origin, &origin_locks, mon->ref, am_port,
-                                   watched, ctx->reason);
-        UnUseTmpHeapNoproc(3);
-
-        rmon = erts_remove_monitor(&ERTS_P_MONITORS(origin), mon->ref);
-        erts_proc_unlock(origin, origin_locks);
-
-        if (rmon) {
-            erts_destroy_monitor(rmon);
-        }
-    }
+    ErtsPortExitContext *pectxt = vpectxt;
+    if (erts_monitor_is_target(mon))
+        erts_proc_sig_send_monitor_down(mon, pectxt->reason);
+    else
+        erts_proc_sig_send_demonitor(mon);
 }
 
 /* 'from' is sending 'this_port' an exit signal, (this_port must be internal).
@@ -3923,9 +3671,12 @@ int
 erts_deliver_port_exit(Port *prt, Eterm from, Eterm reason, int send_closed,
                        int drop_normal)
 {
-   ErtsLink *lnk;
+   ErtsLink *links;
+   ErtsMonitor *monitors;
+   ErtsMonitor *lt_monitors;
    Eterm modified_reason;
    erts_aint32_t state, set_state_flags;
+   ErtsPortExitContext pectxt;
 
    ERTS_CHK_NO_PROC_LOCKS;
    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
@@ -3973,23 +3724,36 @@ erts_deliver_port_exit(Port *prt, Eterm from, Eterm reason, int send_closed,
 
    set_busy_port(ERTS_Port2ErlDrvPort(prt), 0);
 
+   links = ERTS_P_LINKS(prt);
+   ERTS_P_LINKS(prt) = NULL;
+   monitors = ERTS_P_MONITORS(prt);
+   ERTS_P_MONITORS(prt) = NULL;
+   lt_monitors = ERTS_P_LT_MONITORS(prt);
+   ERTS_P_LT_MONITORS(prt) = NULL;
+
    if (prt->common.u.alive.reg != NULL)
        (void) erts_unregister_name(NULL, 0, prt, prt->common.u.alive.reg->name);
 
-   {
-       SweepContext sc = {prt, modified_reason};
-       lnk = ERTS_P_LINKS(prt);
-       ERTS_P_LINKS(prt) = NULL;
-       erts_sweep_links(lnk, &sweep_one_link, &sc);
+   pectxt.port_id = prt->common.id;
+   pectxt.reason = modified_reason;
+
+   if (links)
+       erts_monitor_tree_foreach_delete(&links,
+                                        link_port_exit,
+                                        (void *) &pectxt);
+
+   if (monitors || lt_monitors) {
+       DRV_MONITOR_LOCK_PDL(prt);
+       if (monitors)
+           erts_monitor_tree_foreach_delete(&monitors,
+                                            monitor_port_exit,
+                                            (void *) &pectxt);
+       if (lt_monitors)
+           erts_monitor_list_foreach_delete(&lt_monitors,
+                                            monitor_port_exit,
+                                            (void *) &pectxt);
+       DRV_MONITOR_UNLOCK_PDL(prt);
    }
-   DRV_MONITOR_LOCK_PDL(prt);
-   {
-       SweepContext ctx = {prt, modified_reason};
-       ErtsMonitor *moni = ERTS_P_MONITORS(prt);
-       ERTS_P_MONITORS(prt) = NULL;
-       erts_sweep_monitors(moni, &sweep_one_monitor, &ctx);
-   } 
-   DRV_MONITOR_UNLOCK_PDL(prt);
 
    if ((state & ERTS_PORT_SFLG_DISTRIBUTION) && prt->dist_entry) {
        erts_do_net_exits(prt->dist_entry, modified_reason);
@@ -5069,14 +4833,18 @@ typedef struct {
 
 static void prt_one_monitor(ErtsMonitor *mon, void *vprtd)
 {
+    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
     prt_one_lnk_data *prtd = (prt_one_lnk_data *) vprtd;
-    erts_print(prtd->to, prtd->arg, "(%T,%T)", mon->u.pid, mon->ref);
+    if (mon->type == ERTS_MON_TYPE_RESOURCE && erts_monitor_is_target(mon))
+        erts_print(prtd->to, prtd->arg, "(%p,%T)", mon->other.ptr, mdp->ref);
+    else
+        erts_print(prtd->to, prtd->arg, "(%T,%T)", mon->other.item, mdp->ref);
 }
 
 static void prt_one_lnk(ErtsLink *lnk, void *vprtd)
 {
     prt_one_lnk_data *prtd = (prt_one_lnk_data *) vprtd;
-    erts_print(prtd->to, prtd->arg, "%T", lnk->pid);
+    erts_print(prtd->to, prtd->arg, "%T", lnk->other.item);
 }
 
 static void dump_port_state(fmtfn_t to, void *arg, erts_aint32_t state)
@@ -5188,15 +4956,18 @@ print_port_info(Port *p, fmtfn_t to, void *arg)
 	prtd.to = to;
 	prtd.arg = arg;
 	erts_print(to, arg, "Links: ");
-	erts_doforall_links(ERTS_P_LINKS(p), &prt_one_lnk, &prtd);
+	erts_link_tree_foreach(ERTS_P_LINKS(p), prt_one_lnk, (void *) &prtd);
 	erts_print(to, arg, "\n");
     }
-    if (ERTS_P_MONITORS(p)) {
+    if (ERTS_P_MONITORS(p) || ERTS_P_LT_MONITORS(p)) {
 	prt_one_lnk_data prtd;
 	prtd.to = to;
 	prtd.arg = arg;
 	erts_print(to, arg, "Monitors: ");
-	erts_doforall_monitors(ERTS_P_MONITORS(p), &prt_one_monitor, &prtd);
+	erts_monitor_tree_foreach(ERTS_P_MONITORS(p), prt_one_monitor,
+                                  (void *) &prtd);
+	erts_monitor_list_foreach(ERTS_P_LT_MONITORS(p), prt_one_monitor,
+                                  (void *) &prtd);
 	erts_print(to, arg, "\n");
     }
     if (p->suspended) {
@@ -7033,24 +6804,23 @@ static int do_driver_monitor_process(Port *prt,
 				     ErlDrvMonitor *monitor)
 {
     Eterm buf[ERTS_REF_THING_SIZE];
-    Process *rp;
     Eterm ref;
+    ErtsMonitorData *mdp;
 
-    if (prt->drv_ptr->process_exit == NULL) {
+    if (!prt->drv_ptr->process_exit)
 	return -1;
-    }
-    rp = erts_pid2proc_opt(NULL, 0,
-			   (Eterm) process, ERTS_PROC_LOCK_LINK,
-			   ERTS_P2P_FLG_ALLOW_OTHER_X);
-    if (!rp) {
-	return 1;
-    }
 
     ref = erts_make_ref_in_buffer(buf);
-    erts_add_monitor(&ERTS_P_MONITORS(prt), MON_ORIGIN, ref, rp->common.id, NIL);
-    erts_add_monitor(&ERTS_P_MONITORS(rp), MON_TARGET, ref, prt->common.id, NIL);
+    mdp = erts_monitor_create(ERTS_MON_TYPE_PORT, ref,
+                              prt->common.id, process, NIL);
+
+    if (!erts_proc_sig_send_monitor(&mdp->target, process)) {
+        erts_monitor_release_both(mdp);
+        return 1;
+    }
+
+    erts_monitor_tree_insert(&ERTS_P_MONITORS(prt), &mdp->origin);
 
-    erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
     erts_ref_to_driver_monitor(ref,monitor);
     return 0;
 }
@@ -7083,37 +6853,17 @@ int driver_monitor_process(ErlDrvPort drvport,
 static int do_driver_demonitor_process(Port *prt, const ErlDrvMonitor *monitor)
 {
     Eterm heap[ERTS_REF_THING_SIZE];
-    Process *rp;
     Eterm ref;
     ErtsMonitor *mon;
-    Eterm to;
 
     ref = erts_driver_monitor_to_ref(heap, monitor);
 
-    mon = erts_lookup_monitor(ERTS_P_MONITORS(prt), ref);
-    if (mon == NULL) {
-	return 1;
-    }
-    ASSERT(mon->type == MON_ORIGIN);
-    to = mon->u.pid;
-    ASSERT(is_internal_pid(to));
-    rp = erts_pid2proc_opt(NULL,
-			   0,
-			   to,
-			   ERTS_PROC_LOCK_LINK,
-			   ERTS_P2P_FLG_ALLOW_OTHER_X);
-    mon = erts_remove_monitor(&ERTS_P_MONITORS(prt), ref);
-    if (mon) {
-	erts_destroy_monitor(mon);
-    }
-    if (rp) {
-	ErtsMonitor *rmon;
-	rmon = erts_remove_monitor(&ERTS_P_MONITORS(rp), ref);
-	erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-	if (rmon != NULL) {
-	    erts_destroy_monitor(rmon);
-	}
-    } 
+    mon = erts_monitor_tree_lookup(ERTS_P_MONITORS(prt), ref);
+    if (!mon || !erts_monitor_is_origin(mon))
+        return 1;
+
+    erts_monitor_tree_delete(&ERTS_P_MONITORS(prt), mon);
+    erts_proc_sig_send_demonitor(mon);
     return 0;
 }
 
@@ -7142,19 +6892,16 @@ static ErlDrvTermData do_driver_get_monitored_process(Port *prt,const ErlDrvMoni
 {
     Eterm ref;
     ErtsMonitor *mon;
-    Eterm to;
     Eterm heap[ERTS_REF_THING_SIZE];
 
     ref = erts_driver_monitor_to_ref(heap, monitor);
 
-    mon = erts_lookup_monitor(ERTS_P_MONITORS(prt), ref);
-    if (mon == NULL) {
+    mon = erts_monitor_tree_lookup(ERTS_P_MONITORS(prt), ref);
+    if (!mon || !erts_monitor_is_origin(mon))
 	return driver_term_nil;
-    }
-    ASSERT(mon->type == MON_ORIGIN);
-    to = mon->u.pid;
-    ASSERT(is_internal_pid(to));
-    return (ErlDrvTermData) to;
+
+    ASSERT(is_internal_pid(mon->other.item));
+    return (ErlDrvTermData) mon->other.item;
 }
 
 
@@ -7186,24 +6933,27 @@ int driver_compare_monitors(const ErlDrvMonitor *monitor1,
                       ERTS_REF_THING_SIZE*sizeof(Eterm));
 }
 
-void erts_fire_port_monitor(Port *prt, Eterm ref)
+void erts_fire_port_monitor(Port *prt, ErtsMonitor *tmon)
 {
-    ErtsMonitor *rmon;
+    ErtsMonitorData *mdp;
     void (*callback)(ErlDrvData drv_data, ErlDrvMonitor *monitor);
     ErlDrvMonitor drv_monitor;
     int fpe_was_unmasked;
     ERTS_MSACC_PUSH_STATE_M();
 
     ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
-    ASSERT(prt->drv_ptr != NULL);    
+    ASSERT(prt->drv_ptr != NULL);
+    ASSERT(erts_monitor_is_target(tmon));
+    mdp = erts_monitor_to_data(tmon);
     DRV_MONITOR_LOCK_PDL(prt);
-    if (erts_lookup_monitor(ERTS_P_MONITORS(prt), ref) == NULL) {
+    if (!erts_monitor_is_in_table(&mdp->origin)) {
 	DRV_MONITOR_UNLOCK_PDL(prt);
+        erts_monitor_release(tmon);
 	return;
     }
     callback = prt->drv_ptr->process_exit;
     ASSERT(callback != NULL);
-    erts_ref_to_driver_monitor(ref,&drv_monitor);
+    erts_ref_to_driver_monitor(mdp->ref,&drv_monitor);
     ERTS_MSACC_SET_STATE_CACHED_M(ERTS_MSACC_STATE_PORT);
     DRV_MONITOR_UNLOCK_PDL(prt);
 #ifdef USE_VM_PROBES
@@ -7227,11 +6977,9 @@ void erts_fire_port_monitor(Port *prt, Eterm ref)
     DRV_MONITOR_LOCK_PDL(prt);
     ERTS_MSACC_POP_STATE_M();
     /* remove monitor *after* callback */
-    rmon = erts_remove_monitor(&ERTS_P_MONITORS(prt), ref);
+    erts_monitor_tree_delete(&ERTS_P_MONITORS(prt), &mdp->origin);
     DRV_MONITOR_UNLOCK_PDL(prt);
-    if (rmon) {
-	erts_destroy_monitor(rmon);
-    }
+    erts_monitor_release_both(mdp);
 }
 
 
@@ -7276,8 +7024,7 @@ driver_failure_term(ErlDrvPort ix, Eterm term, int eof)
 int driver_exit(ErlDrvPort ix, int err)
 {
     Port* prt = erts_drvport2port(ix);
-    Process* rp;
-    ErtsLink *lnk, *rlnk = NULL;
+    ErtsLink *lnk;
     Eterm connected;
 
     ERTS_CHK_NO_PROC_LOCKS;
@@ -7286,22 +7033,10 @@ int driver_exit(ErlDrvPort ix, int err)
         return -1;
 
     connected = ERTS_PORT_GET_CONNECTED(prt);
-    rp = erts_pid2proc(NULL, 0, connected, ERTS_PROC_LOCK_LINK);
-    if (rp) {
-	rlnk = erts_remove_link(&ERTS_P_LINKS(rp),prt->common.id);
-    }
-
-    lnk = erts_remove_link(&ERTS_P_LINKS(prt), connected);
-
-    if (rp)
-	erts_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-
-    if (rlnk != NULL) {
-	erts_destroy_link(rlnk);
-    }
-
-    if (lnk != NULL) {
-	erts_destroy_link(lnk);
+    lnk = erts_link_tree_lookup(ERTS_P_LINKS(prt), connected);
+    if (lnk) {
+        erts_link_tree_delete(&ERTS_P_LINKS(prt), lnk);
+        erts_proc_sig_send_unlink(NULL, lnk);
     }
 
     if (err == 0)
diff --git a/erts/emulator/beam/msg_instrs.tab b/erts/emulator/beam/msg_instrs.tab
index d6d4d2fb49..88d2ef9fa3 100644
--- a/erts/emulator/beam/msg_instrs.tab
+++ b/erts/emulator/beam/msg_instrs.tab
@@ -2,7 +2,7 @@
 //
 // %CopyrightBegin%
 //
-// Copyright Ericsson AB 2017. All Rights Reserved.
+// Copyright Ericsson AB 2017-2018. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -45,23 +45,16 @@
 
 i_recv_mark() {
     /*
-     * Save the current position in message buffer.
+     * Save the current end of message queue
      */
-    c_p->msg.saved_last = c_p->msg.last;
+    ERTS_RECV_MARK_SAVE(c_p);
 }
 
 i_recv_set() {
     /*
-     * If c_p->msg.saved_last is non-zero, it points to the first
-     * message that could possibly be matched out.
-     *
-     * If c_p->msg.saved_last is zero, it means that it was invalidated
-     * because another receive was executed before this i_recv_set()
-     * instruction was reached.
+     * If previously saved recv mark, set peek position to it
      */
-    if (c_p->msg.saved_last) {
-        c_p->msg.save = c_p->msg.saved_last;
-    }
+    ERTS_RECV_MARK_SET(c_p);
     SET_I($NEXT_INSTRUCTION);
     goto loop_rec_top__;
     //| -no_next
@@ -79,7 +72,6 @@ i_loop_rec(Dest) {
 
     /* Entry point from recv_set */
  loop_rec_top__:
-    ;
 
     /*
      * We need to disable GC while matching messages
@@ -89,34 +81,59 @@ i_loop_rec(Dest) {
     ASSERT(!(c_p->flags & F_DELAY_GC));
     c_p->flags |= F_DELAY_GC;
 
-    /* Entry point from loop_rec_end */
+    /* Entry point from loop_rec_end (and locally) */
  loop_rec__:
 
+    if (FCALLS <= 0 && FCALLS <= neg_o_reds) {
+        $SET_CP_I_ABS(I);
+        c_p->flags &= ~F_DELAY_GC;
+        SWAPOUT;
+        c_p->arity = 0;
+        c_p->current = NULL;
+        goto do_schedule;
+    }
+
+    ASSERT(!ERTS_PROC_IS_EXITING(c_p));
+
     PROCESS_MAIN_CHK_LOCKS(c_p);
 
     msgp = PEEK_MESSAGE(c_p);
 
-    if (!msgp) {
-        erts_proc_lock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
-        /* Make sure messages wont pass exit signals... */
-        if (ERTS_PROC_PENDING_EXIT(c_p)) {
-            erts_proc_unlock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
-            SWAPOUT;
-            c_p->flags &= ~F_DELAY_GC;
-            c_p->arity = 0;
-            goto do_schedule; /* Will be rescheduled for exit */
-        }
-        ERTS_MSGQ_MV_INQ2PRIVQ(c_p);
-        msgp = PEEK_MESSAGE(c_p);
-        if (msgp) {
-            erts_proc_unlock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
-        } else {
+    if (ERTS_UNLIKELY(msgp == NULL)) {
+        int get_out;
+        SWAPOUT;
+        FCALLS -= erts_proc_sig_receive_helper(c_p, FCALLS, neg_o_reds,
+                                               &msgp, &get_out);
+        SWAPIN;
+        if (ERTS_UNLIKELY(msgp == NULL)) {
+            if (get_out) {
+                if (get_out < 0) {
+                    ASSERT(FCALLS <= 0 && FCALLS <= neg_o_reds);
+                    goto loop_rec__; /* yield */
+                }
+                else {
+                    ASSERT(ERTS_PROC_IS_EXITING(c_p));
+                    goto do_schedule; /* exit */
+                }
+            }
+
+            /*
+             * If there are no more messages in queue
+             * (and we are not yielding or exiting)
+             * erts_proc_sig_receive_helper()
+             * returns with message queue lock locked...
+             */
             c_p->flags &= ~F_DELAY_GC;
             $SET_I_REL($Dest);
             Goto(*I);		/* Jump to a wait or wait_timeout instruction */
         }
     }
-    if (is_non_value(ERL_MESSAGE_TERM(msgp))) {
+
+    ASSERT(msgp == PEEK_MESSAGE(c_p));
+    ASSERT(msgp && ERTS_SIG_IS_MSG(msgp));
+
+    if (ERTS_UNLIKELY(ERTS_SIG_IS_EXTERNAL_MSG(msgp))) {
+        FCALLS -= 10; /* FIXME: bump appropriate amount... */
         SWAPOUT; /* erts_decode_dist_message() may write to heap... */
         if (!erts_decode_dist_message(c_p, ERTS_PROC_LOCK_MAIN, msgp, 0)) {
             /*
@@ -127,13 +144,16 @@ i_loop_rec(Dest) {
             ASSERT(HTOP == c_p->htop && E == c_p->stop);
             /* TODO: Add DTrace probe for this bad message situation? */
             UNLINK_MESSAGE(c_p, msgp);
-            c_p->msg.saved_last = 0; /* Better safe than sorry. */
             msgp->next = NULL;
             erts_cleanup_messages(msgp);
             goto loop_rec__;
         }
         SWAPIN;
     }
+
+    ASSERT(msgp == PEEK_MESSAGE(c_p));
+    ASSERT(ERTS_SIG_IS_INTERNAL_MSG(msgp));
+
     r(0) = ERL_MESSAGE_TERM(msgp);
 }
 
@@ -252,17 +272,8 @@ loop_rec_end(Dest) {
 
     $SET_I_REL($Dest);
     SAVE_MESSAGE(c_p);
-    if (FCALLS > 0 || FCALLS > neg_o_reds) {
-        FCALLS--;
-        goto loop_rec__;
-    }
-
-    c_p->flags &= ~F_DELAY_GC;
-    $SET_CP_I_ABS(I);
-    SWAPOUT;
-    c_p->arity = 0;
-    c_p->current = NULL;
-    goto do_schedule;
+    FCALLS--;
+    goto loop_rec__;
 }
 
 timeout_locked() {