Implementation of true asynchronous signaling between processes

Communication between Erlang processes has conceptually always been
performed through asynchronous signaling. The runtime system
implementation has however previously preformed most operation
synchronously. In a system with only one true thread of execution, this
is not problematic (often the opposite). In a system with multiple threads
of execution (as current runtime system implementation with SMP support)
it becomes problematic. This since it often involves locking of structures
when updating them which in turn cause resource contention. Utilizing
true asynchronous communication often avoids these resource contention
issues.

The case that triggered this change was contention on the link lock due
to frequent updates of the monitor trees during communication with a
frequently used server. The signal order delivery guarantees of the
language makes it hard to change the implementation of only some signals
to use true asynchronous signaling. Therefore the implementations
of (almost) all signals have been changed.

Currently the following signals have been implemented as true
asynchronous signals:
- Message signals
- Exit signals
- Monitor signals
- Demonitor signals
- Monitor triggered signals (DOWN, CHANGE, etc)
- Link signals
- Unlink signals
- Group leader signals

All of the above already defined as asynchronous signals in the
language. The implementation of messages signals was quite
asynchronous to begin with, but had quite strict delivery constraints
due to the ordering guarantees of signals between a pair of processes.

The previously used message queue partitioned into two halves has been
replaced by a more general signal queue partitioned into three parts
that service all kinds of signals. More details regarding the signal
queue can be found in comments in the erl_proc_sig_queue.h file.

The monitor and link implementations have also been completely replaced
in order to fit the new asynchronous signaling implementation as good
as possible. More details regarding the new monitor and link
implementations can be found in the erl_monitor_link.h file.

1 files changed, 572 insertions, 344 deletions

diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 6475f04c56..9a3c058e82 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;
     }
 }
 
@@ -743,7 +857,7 @@ 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()
@@ -758,23 +872,79 @@ 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
@@ -794,6 +964,7 @@ 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;
 
@@ -845,9 +1016,14 @@ 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) {
@@ -856,38 +1032,9 @@ 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
@@ -899,16 +1046,23 @@ 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;
 	}
     }
 
@@ -948,6 +1102,8 @@ 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;
 }
 
@@ -971,8 +1127,8 @@ 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__);
 	}
@@ -989,7 +1145,7 @@ 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)
@@ -1011,8 +1167,8 @@ 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__);
@@ -1027,44 +1183,23 @@ 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;
@@ -1081,11 +1216,14 @@ 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);
 
     /*
@@ -1144,14 +1282,15 @@ 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;
@@ -1162,16 +1301,17 @@ 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
@@ -1179,7 +1319,7 @@ 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;
 
@@ -1192,6 +1332,11 @@ 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;
@@ -1199,7 +1344,7 @@ 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: {
@@ -1209,7 +1354,7 @@ 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;
@@ -1218,6 +1363,12 @@ 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;
     }
@@ -1227,12 +1378,14 @@ 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.
 		 */
@@ -1252,11 +1405,28 @@ 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));
 
@@ -1266,6 +1436,12 @@ 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;
     }
@@ -1276,20 +1452,34 @@ 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;
     }
@@ -1306,11 +1496,11 @@ 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;
@@ -1334,12 +1524,17 @@ 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);
 
@@ -1347,18 +1542,22 @@ 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;
@@ -1415,7 +1614,6 @@ process_info_aux(Process *BIF_P,
     }
 
     case am_total_heap_size: {
-	ErtsMessage *mp;
 	Uint total_heap_size;
 	Uint hsz = 3;
 
@@ -1425,10 +1623,19 @@ 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);
@@ -1451,6 +1658,12 @@ 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;
     }
 
@@ -1523,10 +1736,14 @@ 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);
@@ -1629,6 +1846,8 @@ 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;
     }
 
@@ -2863,6 +3082,16 @@ 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:
@@ -2898,7 +3127,7 @@ 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;
@@ -2922,11 +3151,11 @@ 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;
@@ -2935,11 +3164,10 @@ 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;
@@ -2958,15 +3186,19 @@ 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;
@@ -3043,7 +3275,12 @@ 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);
 
@@ -3278,8 +3515,7 @@ 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);
@@ -3311,16 +3547,6 @@ 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
@@ -3693,22 +3919,59 @@ 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])) {
@@ -3719,19 +3982,20 @@ 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);
 		    }
@@ -3740,27 +4004,54 @@ 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);
@@ -3778,18 +4069,6 @@ 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)) {
@@ -4116,57 +4395,6 @@ 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)) {