Optimize process state changes

23 files changed, 2206 insertions, 2294 deletions

diff --git a/erts/emulator/beam/beam_bp.c b/erts/emulator/beam/beam_bp.c
index f4e7119d4d..a6e00f87e0 100644
--- a/erts/emulator/beam/beam_bp.c
+++ b/erts/emulator/beam/beam_bp.c
@@ -713,7 +713,7 @@ void erts_trace_time_break(Process *p, BeamInstr *pc, BpDataTime *bdt, Uint type
     BpDataTime *pbdt = NULL;
 
     ASSERT(p);
-    ASSERT(p->status == P_RUNNING);
+    ASSERT(ERTS_PSFLG_RUNNING & erts_smp_atomic32_read_acqb(&p->state));
 
     /* get previous timestamp and breakpoint
      * from the process psd  */
diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index 5ca3e8060b..b831147295 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -1875,13 +1875,12 @@ void process_main(void)
 	 msgp = PEEK_MESSAGE(c_p);
 	 if (msgp)
 	     erts_smp_proc_unlock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
-	 else {
+	 else
 #endif
+	 {
 	     SET_I((BeamInstr *) Arg(0));
 	     Goto(*I);		/* Jump to a wait or wait_timeout instruction */
-#ifdef ERTS_SMP
 	 }
-#endif
      }
      ErtsMoveMsgAttachmentIntoProc(msgp, c_p, E, HTOP, FCALLS,
 				   {
@@ -2110,11 +2109,11 @@ void process_main(void)
 	 OpCase(wait_f):
 
 	 wait2: {
-	     ASSERT(!ERTS_PROC_IS_EXITING(c_p));
 	     c_p->i = (BeamInstr *) Arg(0); /* L1 */
 	     SWAPOUT;
 	     c_p->arity = 0;
-	     c_p->status = P_WAITING;
+	     erts_smp_atomic32_read_band_relb(&c_p->state, ~ERTS_PSFLG_ACTIVE);
+	     ASSERT(!ERTS_PROC_IS_EXITING(c_p));
 	     erts_smp_proc_unlock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
 	     c_p->current = NULL;
 	     goto do_schedule;
@@ -3193,10 +3192,6 @@ void process_main(void)
      c_p->arg_reg[0] = r(0);
      SWAPOUT;
      c_p->i = I;
-     erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_STATUS);
-     if (c_p->status != P_SUSPENDED)
-	 erts_add_to_runq(c_p);
-     erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_STATUS);
      goto do_schedule1;
  }
 
@@ -5159,9 +5154,6 @@ void process_main(void)
      c_p->arity = 1; /* One living register (the 'true' return value) */
      SWAPOUT;
      c_p->i = I + 1; /* Next instruction */
-     erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_STATUS);
-     erts_add_to_runq(c_p);
-     erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_STATUS);
      c_p->current = NULL;
      goto do_schedule;
  }
@@ -6255,9 +6247,7 @@ erts_hibernate(Process* c_p, Eterm module, Eterm function, Eterm args, Eterm* re
      */
     erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS);
     ERTS_SMP_MSGQ_MV_INQ2PRIVQ(c_p);
-    if (c_p->msg.len > 0) {
-	erts_add_to_runq(c_p);
-    } else {
+    if (!c_p->msg.len) {
 	erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS);
 	c_p->fvalue = NIL;
 	PROCESS_MAIN_CHK_LOCKS(c_p);
@@ -6265,14 +6255,12 @@ erts_hibernate(Process* c_p, Eterm module, Eterm function, Eterm args, Eterm* re
 	ERTS_VERIFY_UNUSED_TEMP_ALLOC(c_p);
 	PROCESS_MAIN_CHK_LOCKS(c_p);
 	erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS);
-	ASSERT(!ERTS_PROC_IS_EXITING(c_p));
 #ifdef ERTS_SMP
 	ERTS_SMP_MSGQ_MV_INQ2PRIVQ(c_p);
-	if (c_p->msg.len > 0)
-	    erts_add_to_runq(c_p);
-	else
+	if (!c_p->msg.len)
 #endif
-	    c_p->status = P_WAITING;
+	    erts_smp_atomic32_read_band_relb(&c_p->state, ~ERTS_PSFLG_ACTIVE);
+	ASSERT(!ERTS_PROC_IS_EXITING(c_p));
     }
     erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS);
     c_p->current = bif_export[BIF_hibernate_3]->code;
diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index dd9488afa6..160b1ef0fc 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -233,15 +233,17 @@ BIF_RETTYPE link_1(BIF_ALIST_1)
 
     BIF_ERROR(BIF_P, BADARG);
 
- res_no_proc:
-    if (BIF_P->flags & F_TRAPEXIT) {
-	ErtsProcLocks locks = ERTS_PROC_LOCK_MAIN;
-	erts_deliver_exit_message(BIF_ARG_1, BIF_P, &locks, am_noproc, NIL);
-	erts_smp_proc_unlock(BIF_P, ~ERTS_PROC_LOCK_MAIN & locks);
-	BIF_RET(am_true);
+res_no_proc: {
+	erts_aint32_t state = erts_smp_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_smp_proc_unlock(BIF_P, ~ERTS_PROC_LOCK_MAIN & locks);
+	    BIF_RET(am_true);
+	}
+	else
+	    BIF_ERROR(BIF_P, EXC_NOPROC);
     }
-    else
-	BIF_ERROR(BIF_P, EXC_NOPROC);
 }
 
 #define ERTS_DEMONITOR_FALSE		2
@@ -1103,8 +1105,9 @@ BIF_RETTYPE hibernate_3(BIF_ALIST_3)
 
     if (erts_hibernate(BIF_P, BIF_ARG_1, BIF_ARG_2, BIF_ARG_3, reg)) {
         /*
-         * If hibernate succeeded, TRAP. The process will be suspended
-         * if status is P_WAITING or continue (if any message was in the queue).
+         * If hibernate succeeded, TRAP. The process will be wait in a
+         * hibernated state if its state is inactive (!ERTS_PSFLG_ACTIVE);
+         * otherwise, continue executing (if any message was in the queue).
          */
         BIF_TRAP_CODE_PTR_(BIF_P, BIF_P->i);
     }
@@ -1499,14 +1502,13 @@ BIF_RETTYPE process_flag_2(BIF_ALIST_2)
       BIF_RET(old_value);
    }
    else if (BIF_ARG_1 == am_priority) {
-       erts_smp_proc_lock(BIF_P, ERTS_PROC_LOCK_STATUS);
        old_value = erts_set_process_priority(BIF_P, BIF_ARG_2);
-       erts_smp_proc_unlock(BIF_P, ERTS_PROC_LOCK_STATUS);
        if (old_value == THE_NON_VALUE)
 	   goto error;
        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;
@@ -1521,59 +1523,52 @@ BIF_RETTYPE process_flag_2(BIF_ALIST_2)
 	*       For more info, see implementation of erts_send_exit_signal().
 	*/
        erts_smp_proc_lock(BIF_P, ERTS_PROC_LOCK_STATUS);
+       ERTS_SMP_LC_ASSERT((ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_STATUS)
+			  & erts_proc_lc_my_proc_locks(BIF_P));
        ERTS_SMP_BIF_CHK_PENDING_EXIT(BIF_P,
 				     ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_STATUS);
-       old_value = ERTS_PROC_IS_TRAPPING_EXITS(BIF_P) ? am_true : am_false;
-       if (trap_exit) {
-	   ERTS_PROC_SET_TRAP_EXIT(BIF_P);
-       } else {
-	   ERTS_PROC_UNSET_TRAP_EXIT(BIF_P);
-       }
+       if (trap_exit)
+	   state = erts_smp_atomic32_read_bor_nob(&BIF_P->state,
+						  ERTS_PSFLG_TRAP_EXIT);
+       else
+	   state = erts_smp_atomic32_read_band_nob(&BIF_P->state,
+						   ~ERTS_PSFLG_TRAP_EXIT);
+       old_value = (state & ERTS_PSFLG_TRAP_EXIT) ? am_true : am_false;
        erts_smp_proc_unlock(BIF_P, ERTS_PROC_LOCK_STATUS);
        BIF_RET(old_value);
    }
    else if (BIF_ARG_1 == am_scheduler) {
-       int yield;
-       ErtsRunQueue *old;
-       ErtsRunQueue *new;
+       ErtsRunQueue *old, *new, *curr;
        Sint sched;
+       erts_aint32_t state;
+
        if (!is_small(BIF_ARG_2))
 	   goto error;
        sched = signed_val(BIF_ARG_2);
        if (sched < 0 || erts_no_schedulers < sched)
 	   goto error;
-       erts_smp_proc_lock(BIF_P, ERTS_PROC_LOCK_STATUS);
-       old = BIF_P->bound_runq;
-#ifdef ERTS_SMP
-       ASSERT(!old || old == BIF_P->run_queue);
-#endif
-       new = !sched ? NULL : erts_schedid2runq(sched);
-#ifndef ERTS_SMP
-       yield = 0;
-#else
-       if (new == old)
-	   yield = 0;
+
+       if (sched == 0) {
+	   new = NULL;
+	   state = erts_smp_atomic32_read_band_mb(&BIF_P->state,
+						  ~ERTS_PSFLG_BOUND);
+       }
        else {
-	   ErtsRunQueue *curr = BIF_P->run_queue;
-	   if (!new)
-	       erts_smp_runq_lock(curr);
-	   else
-	       erts_smp_runqs_lock(curr, new);
-	   yield = new && BIF_P->run_queue != new;
-#endif
-	   BIF_P->bound_runq = new;
+	   new = erts_schedid2runq(sched);
 #ifdef ERTS_SMP
-	   if (new)
-	       BIF_P->run_queue = new;
-	   if (!new)
-	       erts_smp_runq_unlock(curr);
-	   else
-	       erts_smp_runqs_unlock(curr, new);
-       }
+	   erts_atomic_set_nob(&BIF_P->run_queue, (erts_aint_t) new);
 #endif
-       erts_smp_proc_unlock(BIF_P, ERTS_PROC_LOCK_STATUS);
+	   state = erts_smp_atomic32_read_bor_mb(&BIF_P->state,
+						 ERTS_PSFLG_BOUND);
+       }
+
+       curr = ERTS_GET_SCHEDULER_DATA_FROM_PROC(BIF_P)->run_queue;
+       old = (ERTS_PSFLG_BOUND & state) ? curr : NULL;
+
+       ASSERT(!old || old == curr);
+
        old_value = old ? make_small(old->ix+1) : make_small(0);
-       if (yield)
+       if (new && new != curr)
 	   ERTS_BIF_YIELD_RETURN_X(BIF_P, old_value, am_scheduler);
        else
 	   BIF_RET(old_value);
diff --git a/erts/emulator/beam/break.c b/erts/emulator/beam/break.c
index 0a5fc26ee8..9cb5f2cc16 100644
--- a/erts/emulator/beam/break.c
+++ b/erts/emulator/beam/break.c
@@ -73,8 +73,8 @@ process_info(int to, void *to_arg)
     for (i = 0; i < erts_max_processes; i++) {
 	Process *p = erts_pix2proc(i);
 	if (p && p->i != ENULL) {
-	   if (p->status != P_EXITING)
-	       print_process_info(to, to_arg, p);
+	    if (!ERTS_PROC_IS_EXITING(p))
+		print_process_info(to, to_arg, p);
 	}
     }
 
@@ -99,11 +99,20 @@ process_killer(void)
 		if ((j = sys_get_key(0)) <= 0)
 		    erl_exit(0, "");
 		switch(j) {
-		case 'k':
-		    if (rp->status == P_WAITING) {
-			ErtsProcLocks rp_locks = ERTS_PROC_LOCKS_XSIG_SEND;
-			erts_smp_proc_inc_refc(rp);
-			erts_smp_proc_lock(rp, rp_locks);
+		case 'k': {
+		    ErtsProcLocks rp_locks = ERTS_PROC_LOCKS_XSIG_SEND;
+		    erts_aint32_t state;
+		    erts_smp_proc_inc_refc(rp);
+		    erts_smp_proc_lock(rp, rp_locks);
+		    state = erts_smp_atomic32_read_acqb(&rp->state);
+		    if (state & (ERTS_PSFLG_FREE
+				  | ERTS_PSFLG_EXITING
+				  | ERTS_PSFLG_ACTIVE
+				  | ERTS_PSFLG_IN_RUNQ
+				  | ERTS_PSFLG_RUNNING)) {
+			erts_printf("Can only kill WAITING processes this way\n");
+		    }
+		    else {
 			(void) erts_send_exit_signal(NULL,
 						     NIL,
 						     rp,
@@ -112,12 +121,10 @@ process_killer(void)
 						     NIL,
 						     NULL,
 						     0);
-			erts_smp_proc_unlock(rp, rp_locks);
-			erts_smp_proc_dec_refc(rp);
 		    }
-		    else
-			erts_printf("Can only kill WAITING processes this way\n");
-
+		    erts_smp_proc_unlock(rp, rp_locks);
+		    erts_smp_proc_dec_refc(rp);
+		}
 		case 'n': br = 1; break;
 		case 'r': return;
 		default: return;
@@ -186,38 +193,34 @@ print_process_info(int to, void *to_arg, Process *p)
     int garbing = 0;
     int running = 0;
     struct saved_calls *scb;
+    erts_aint32_t state;
 
     /* display the PID */
     erts_print(to, to_arg, "=proc:%T\n", p->id);
 
     /* Display the state */
     erts_print(to, to_arg, "State: ");
-    switch (p->status) {
-    case P_FREE:
+
+    state = erts_smp_atomic32_read_acqb(&p->state);
+    if (state & ERTS_PSFLG_FREE)
 	erts_print(to, to_arg, "Non Existing\n"); /* Should never happen */
-	break;
-    case P_RUNABLE:
-	erts_print(to, to_arg, "Scheduled\n");
-	break;
-    case P_WAITING:
-	erts_print(to, to_arg, "Waiting\n");
-	break;
-    case P_SUSPENDED:
-	erts_print(to, to_arg, "Suspended\n");
-	break;
-    case P_RUNNING:
-	erts_print(to, to_arg, "Running\n");
-	running = 1;
-	break;
-    case P_EXITING:
+    else if (state & ERTS_PSFLG_EXITING)
 	erts_print(to, to_arg, "Exiting\n");
-	break;
-    case P_GARBING:
-	erts_print(to, to_arg, "Garbing\n");
+    else if (state & ERTS_PSFLG_GC) {
 	garbing = 1;
 	running = 1;
-	break;
+	erts_print(to, to_arg, "Garbing\n");
+    }
+    else if (state & ERTS_PSFLG_SUSPENDED)
+	erts_print(to, to_arg, "Suspended\n");
+    else if (state & ERTS_PSFLG_RUNNING) {
+	running = 1;
+	erts_print(to, to_arg, "Running\n");
     }
+    else if (state & ERTS_PSFLG_ACTIVE)
+	erts_print(to, to_arg, "Scheduled\n");
+    else
+	erts_print(to, to_arg, "Waiting\n");
 
     /*
      * If the process is registered as a global process, display the
diff --git a/erts/emulator/beam/erl_alloc.types b/erts/emulator/beam/erl_alloc.types
index b30e6dc018..d1e3b4b0ef 100644
--- a/erts/emulator/beam/erl_alloc.types
+++ b/erts/emulator/beam/erl_alloc.types
@@ -336,6 +336,8 @@ type	SL_PTIMER	SHORT_LIVED	SYSTEM		ptimer_sl
 type	LL_PTIMER	STANDARD	SYSTEM		ptimer_ll
 type	SYS_MSG_Q	SHORT_LIVED	PROCESSES	system_messages_queue
 type	FP_EXCEPTION	LONG_LIVED	SYSTEM		fp_exception
+type	LL_MPATHS	LONG_LIVED	SYSTEM		ll_migration_paths
+type	SL_MPATHS	SHORT_LIVED	SYSTEM		sl_migration_paths
 +endif
 
 +if hipe
diff --git a/erts/emulator/beam/erl_alloc_util.c b/erts/emulator/beam/erl_alloc_util.c
index e0d525bdde..62225d3572 100644
--- a/erts/emulator/beam/erl_alloc_util.c
+++ b/erts/emulator/beam/erl_alloc_util.c
@@ -832,14 +832,14 @@ init_dd_queue(ErtsAllctrDDQueue_t *ddq)
 static ERTS_INLINE erts_aint_t
 ddq_managed_thread_enqueue(ErtsAllctrDDQueue_t *ddq, void *ptr)
 {
-    erts_aint_t ilast, itmp;
+    erts_aint_t first_ilast, ilast, itmp;
     ErtsAllctrDDBlock_t *this = ptr;
 
     erts_atomic_init_nob(&this->atmc_next, ERTS_AINT_NULL);
 
     /* Enqueue at end of list... */
 
-    ilast = erts_atomic_read_nob(&ddq->tail.data.last);
+    first_ilast = ilast = erts_atomic_read_nob(&ddq->tail.data.last);
     while (1) {
 	ErtsAllctrDDBlock_t *last = (ErtsAllctrDDBlock_t *) ilast;
 	itmp = erts_atomic_cmpxchg_mb(&last->atmc_next,
@@ -853,8 +853,11 @@ ddq_managed_thread_enqueue(ErtsAllctrDDQueue_t *ddq, void *ptr)
     /* Move last pointer forward... */
     while (1) {
 	if (erts_atomic_read_rb(&this->atmc_next) != ERTS_AINT_NULL) {
-	    /* Someone else will move it forward */
-	    return erts_atomic_read_rb(&ddq->tail.data.last);
+	    ilast = erts_atomic_read_rb(&ddq->tail.data.last);
+	    if (first_ilast != ilast) {
+		/* Someone else will move it forward */
+		return ilast;
+	    }
 	}
 	itmp = erts_atomic_cmpxchg_mb(&ddq->tail.data.last,
 				      (erts_aint_t) this,
diff --git a/erts/emulator/beam/erl_bif_ddll.c b/erts/emulator/beam/erl_bif_ddll.c
index c338ee1c4b..7f7c975e78 100644
--- a/erts/emulator/beam/erl_bif_ddll.c
+++ b/erts/emulator/beam/erl_bif_ddll.c
@@ -368,13 +368,11 @@ BIF_RETTYPE erl_ddll_try_load_3(BIF_ALIST_3)
 #endif
 	for (j = 0; j < erts_max_ports; j++) {
 	    Port* prt = &erts_port[j];
-#ifdef DDLL_SMP
 	    erts_smp_port_state_lock(prt);
-#endif 
 	    if (!(prt->status & FREE_PORT_FLAGS) &&
 		prt->drv_ptr->handle == dh) {
-#if DDLL_SMP
 		erts_smp_atomic_inc_nob(&prt->refc);
+#if DDLL_SMP
 		/* Extremely rare spinlock */
 		while(prt->status & ERTS_PORT_SFLG_INITIALIZING) {
 		       erts_smp_port_state_unlock(prt);
@@ -598,13 +596,11 @@ done:
 #endif
 	for (j = 0; j < erts_max_ports; j++) {
 	    Port* prt = &erts_port[j];
-#if DDLL_SMP
 	    erts_smp_port_state_lock(prt);
-#endif
 	    if (!(prt->status &  FREE_PORT_FLAGS) 
 		&& prt->drv_ptr->handle == dh) {
-#if DDLL_SMP
 		erts_smp_atomic_inc_nob(&prt->refc);
+#if DDLL_SMP
 		/* Extremely rare spinlock */
 		while(prt->status & ERTS_PORT_SFLG_INITIALIZING) {
 		       erts_smp_port_state_unlock(prt);
@@ -1060,13 +1056,11 @@ void erts_ddll_proc_dead(Process *p, ErtsProcLocks plocks)
 #endif
 		    for (j = 0; j < erts_max_ports; j++) {
 			Port* prt = &erts_port[j];
-#if DDLL_SMP
 			erts_smp_port_state_lock(prt);
-#endif
 			if (!(prt->status & FREE_PORT_FLAGS) &&
 			    prt->drv_ptr->handle == dh) {
-#if DDLL_SMP
 			    erts_smp_atomic_inc_nob(&prt->refc);
+#if DDLL_SMP
 			    while(prt->status & ERTS_PORT_SFLG_INITIALIZING) {
 				erts_smp_port_state_unlock(prt);
 				erts_smp_port_state_lock(prt);
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 8117b1bfaa..90ddaa4fac 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -1355,13 +1355,15 @@ process_info_aux(Process *BIF_P,
 	hp = HAlloc(BIF_P, 3);
 	break;
 
-    case am_trap_exit:
+    case am_trap_exit: {
+	erts_aint32_t state = erts_smp_atomic32_read_nob(&rp->state);
 	hp = HAlloc(BIF_P, 3);
-	if (rp->flags  & F_TRAPEXIT)
+	if (state & ERTS_PSFLG_TRAP_EXIT)
 	    res = am_true;
 	else
 	    res = am_false;
 	break;
+    }
 
     case am_error_handler:
 	hp = HAlloc(BIF_P, 3);
@@ -3144,14 +3146,8 @@ BIF_RETTYPE is_process_alive_1(BIF_ALIST_1)
 	   BIF_RET(am_false);
        }
        else {
-	   int px;
-#ifdef ERTS_SMP
-	   px = (erts_atomic32_read_acqb(&rp->aflags)
-		 & (ERTS_PROC_AFLG_PENDING_EXIT|ERTS_PROC_AFLG_EXITING));
-#else
-	   px = 0;
-#endif
-	   if (px)
+	   if (erts_smp_atomic32_read_acqb(&rp->state)
+		 & (ERTS_PSFLG_PENDING_EXIT|ERTS_PSFLG_EXITING))
 	       ERTS_BIF_AWAIT_X_DATA_TRAP(BIF_P, BIF_ARG_1, am_false);
 	   else
 	       BIF_RET(am_true);
diff --git a/erts/emulator/beam/erl_cpu_topology.c b/erts/emulator/beam/erl_cpu_topology.c
index fe3693d0ca..41e71881a0 100644
--- a/erts/emulator/beam/erl_cpu_topology.c
+++ b/erts/emulator/beam/erl_cpu_topology.c
@@ -486,7 +486,7 @@ erts_sched_check_cpu_bind_post_suspend(ErtsSchedulerData *esdp)
 	erts_thr_set_main_status(1, (int) esdp->no);
 
     /* Make sure we check if we should bind to a cpu or not... */
-    esdp->run_queue->flags |= ERTS_RUNQ_FLG_CHK_CPU_BIND;
+    ERTS_RUNQ_FLGS_SET(esdp->run_queue, ERTS_RUNQ_FLG_CHK_CPU_BIND);
 }
 
 #endif
@@ -498,9 +498,6 @@ erts_sched_check_cpu_bind(ErtsSchedulerData *esdp)
     erts_cpu_groups_map_t *cgm;
     erts_cpu_groups_callback_list_t *cgcl;
     erts_cpu_groups_callback_call_t *cgcc;
-#ifdef ERTS_SMP
-    esdp->run_queue->flags &= ~ERTS_RUNQ_FLG_CHK_CPU_BIND;
-#endif
     erts_smp_runq_unlock(esdp->run_queue);
     erts_smp_rwmtx_rwlock(&cpuinfo_rwmtx);
     cpu_id = scheduler2cpu_map[esdp->no].bind_id;
diff --git a/erts/emulator/beam/erl_gc.c b/erts/emulator/beam/erl_gc.c
index 52a6e52e6c..6075a527c3 100644
--- a/erts/emulator/beam/erl_gc.c
+++ b/erts/emulator/beam/erl_gc.c
@@ -357,11 +357,7 @@ erts_garbage_collect(Process* p, int need, Eterm* objv, int nobj)
         trace_gc(p, am_gc_start);
     }
 
-    erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
-    p->gcstatus = p->status;
-    p->status = P_GARBING;
-    erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
-
+    erts_smp_atomic32_read_bor_nob(&p->state, ERTS_PSFLG_GC);
     if (erts_system_monitor_long_gc != 0) {
 	get_now(&ms1, &s1, &us1);
     }
@@ -404,9 +400,8 @@ erts_garbage_collect(Process* p, int need, Eterm* objv, int nobj)
 
     ErtsGcQuickSanityCheck(p);
 
-    erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
-    p->status = p->gcstatus;
-    erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
+    erts_smp_atomic32_read_band_nob(&p->state, ~ERTS_PSFLG_GC);
+
     if (IS_TRACED_FL(p, F_TRACE_GC)) {
         trace_gc(p, am_gc_end);
     }
@@ -490,10 +485,7 @@ erts_garbage_collect_hibernate(Process* p)
     /*
      * Preliminaries.
      */
-    erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
-    p->gcstatus = p->status;
-    p->status = P_GARBING;
-    erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
+    erts_smp_atomic32_read_bor_nob(&p->state, ERTS_PSFLG_GC);
     ErtsGcQuickSanityCheck(p);
     ASSERT(p->mbuf_sz == 0);
     ASSERT(p->mbuf == 0);
@@ -604,9 +596,7 @@ erts_garbage_collect_hibernate(Process* p)
 
     ErtsGcQuickSanityCheck(p);
 
-    erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
-    p->status = p->gcstatus;
-    erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
+    erts_smp_atomic32_read_band_nob(&p->state, ~ERTS_PSFLG_GC);
 }
 
 
@@ -630,10 +620,7 @@ erts_garbage_collect_literals(Process* p, Eterm* literals,
     /*
      * Set GC state.
      */
-    erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
-    p->gcstatus = p->status;
-    p->status = P_GARBING;
-    erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
+    erts_smp_atomic32_read_bor_nob(&p->state, ERTS_PSFLG_GC);
 
     /*
      * We assume that the caller has already done a major collection
@@ -775,9 +762,7 @@ erts_garbage_collect_literals(Process* p, Eterm* literals,
     /*
      * Restore status.
      */
-    erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
-    p->status = p->gcstatus;
-    erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
+    erts_smp_atomic32_read_band_nob(&p->state, ~ERTS_PSFLG_GC);
 }
 
 static int
diff --git a/erts/emulator/beam/erl_lock_check.c b/erts/emulator/beam/erl_lock_check.c
index 306cb652c4..175695e856 100644
--- a/erts/emulator/beam/erl_lock_check.c
+++ b/erts/emulator/beam/erl_lock_check.c
@@ -82,7 +82,6 @@ static erts_lc_lock_order_t erts_lock_order[] = {
 #ifdef ERTS_SMP
     {	"bif_timers",				NULL			},
     {	"reg_tab",				NULL			},
-    {	"migration_info_update",		NULL			},
     {	"proc_main",				"pid"			},
 #ifdef HIPE
     {	"hipe_mfait_lock",			NULL			},
@@ -124,6 +123,7 @@ static erts_lc_lock_order_t erts_lock_order[] = {
     {   "removed_fd_pre_alloc_lock",            "address"               },
     {   "state_prealloc",                       NULL                    },
     {	"schdlr_sspnd",				NULL			},
+    {	"migration_info_update",		NULL			},
     {	"run_queue",				"address"		},
     {	"cpu_info",				NULL			},
     {	"pollset",				"address"		},
diff --git a/erts/emulator/beam/erl_message.c b/erts/emulator/beam/erl_message.c
index 4a797fbeae..b10964da52 100644
--- a/erts/emulator/beam/erl_message.c
+++ b/erts/emulator/beam/erl_message.c
@@ -297,38 +297,6 @@ erts_msg_distext2heap(Process *pp,
     return THE_NON_VALUE;
  }
 
-static ERTS_INLINE void
-notify_new_message(Process *receiver)
-{
-    ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_STATUS
-		       & erts_proc_lc_my_proc_locks(receiver));
-
-    ACTIVATE(receiver);
-
-    switch (receiver->status) {
-    case P_GARBING:
-	switch (receiver->gcstatus) {
-	case P_SUSPENDED:
-	    goto suspended;
-	case P_WAITING:
-	    goto waiting;
-	default:
-	    break;
-	}
-	break;
-    case P_SUSPENDED:
-    suspended:
-	receiver->rstatus = P_RUNABLE;
-	break;
-    case P_WAITING:
-    waiting:
-	erts_add_to_runq(receiver);
-	break;
-    default:
-	break;
-    }
-}
-
 void
 erts_queue_dist_message(Process *rcvr,
 			ErtsProcLocks *rcvr_locks,
@@ -342,7 +310,7 @@ erts_queue_dist_message(Process *rcvr,
     Sint tok_serial = 0;
 #endif
 #ifdef ERTS_SMP
-    ErtsProcLocks need_locks;
+    erts_aint_t state;
 #endif
 
     ERTS_SMP_LC_ASSERT(*rcvr_locks == erts_proc_lc_my_proc_locks(rcvr));
@@ -350,20 +318,21 @@ erts_queue_dist_message(Process *rcvr,
     mp = message_alloc();
 
 #ifdef ERTS_SMP
-    need_locks = ~(*rcvr_locks) & (ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS);
-    if (need_locks) {
-	*rcvr_locks |= need_locks;
-	if (erts_smp_proc_trylock(rcvr, need_locks) == EBUSY) {
-	    if (need_locks == ERTS_PROC_LOCK_MSGQ) {
+    if (!(*rcvr_locks & ERTS_PROC_LOCK_MSGQ)) {
+	if (erts_smp_proc_trylock(rcvr, ERTS_PROC_LOCK_MSGQ) == EBUSY) {
+	    ErtsProcLocks need_locks = ERTS_PROC_LOCK_MSGQ;
+	    if (*rcvr_locks & ERTS_PROC_LOCK_STATUS) {
 		erts_smp_proc_unlock(rcvr, ERTS_PROC_LOCK_STATUS);
-		need_locks = (ERTS_PROC_LOCK_MSGQ
-			      | ERTS_PROC_LOCK_STATUS);
+		need_locks |= ERTS_PROC_LOCK_STATUS;
 	    }
 	    erts_smp_proc_lock(rcvr, need_locks);
 	}
     }
 
-    if (ERTS_PROC_IS_EXITING(rcvr) || ERTS_PROC_PENDING_EXIT(rcvr)) {
+    state = erts_smp_atomic32_read_acqb(&rcvr->state);
+    if (state & (ERTS_PSFLG_PENDING_EXIT|ERTS_PSFLG_EXITING)) {
+	if (!(*rcvr_locks & ERTS_PROC_LOCK_MSGQ))
+	    erts_smp_proc_unlock(rcvr, ERTS_PROC_LOCK_MSGQ);
 	/* Drop message if receiver is exiting or has a pending exit ... */
 	if (is_not_nil(token)) {
 	    ErlHeapFragment *heap_frag;
@@ -379,6 +348,8 @@ erts_queue_dist_message(Process *rcvr,
 	/* Ahh... need to decode it in order to trace it... */
 	ErlHeapFragment *mbuf;
 	Eterm msg;
+	if (!(*rcvr_locks & ERTS_PROC_LOCK_MSGQ))
+	    erts_smp_proc_unlock(rcvr, ERTS_PROC_LOCK_MSGQ);
 	message_free(mp);
 	msg = erts_msg_distext2heap(rcvr, rcvr_locks, &mbuf, &token, dist_ext);
 	if (is_value(msg))
@@ -440,26 +411,32 @@ erts_queue_dist_message(Process *rcvr,
 	mp->data.dist_ext = dist_ext;
 	LINK_MESSAGE(rcvr, mp);
 
-	notify_new_message(rcvr);
+	if (!(*rcvr_locks & ERTS_PROC_LOCK_MSGQ))
+	    erts_smp_proc_unlock(rcvr, ERTS_PROC_LOCK_MSGQ);
+
+	erts_proc_notify_new_message(rcvr);
     }
 }
 
 /* Add a message last in message queue */
-void
-erts_queue_message(Process* receiver,
-		   ErtsProcLocks *receiver_locks,
-		   ErlHeapFragment* bp,
-		   Eterm message,
-		   Eterm seq_trace_token
+static int
+queue_message(Process *c_p,
+	      Process* receiver,
+	      ErtsProcLocks *receiver_locks,
+	      erts_aint32_t *receiver_state,
+	      ErlHeapFragment* bp,
+	      Eterm message,
+	      Eterm seq_trace_token
 #ifdef USE_VM_PROBES
 		   , Eterm dt_utag
 #endif
-)
+    )
 {
     ErlMessage* mp;
-#ifdef ERTS_SMP
-    ErtsProcLocks need_locks;
-#else
+    int locked_msgq = 0;
+    erts_aint_t state;
+
+#ifndef ERTS_SMP
     ASSERT(bp != NULL || receiver->mbuf == NULL);
 #endif
 
@@ -467,31 +444,45 @@ erts_queue_message(Process* receiver,
 
     mp = message_alloc();
 
+    if (receiver_state)
+	state = *receiver_state;
+    else
+	state = erts_smp_atomic32_read_acqb(&receiver->state);
+
 #ifdef ERTS_SMP
-    need_locks = ~(*receiver_locks) & (ERTS_PROC_LOCK_MSGQ
-				       | ERTS_PROC_LOCK_STATUS);
-    if (need_locks) {
-	*receiver_locks |= need_locks;
-	if (erts_smp_proc_trylock(receiver, need_locks) == EBUSY) {
-	    if (need_locks == ERTS_PROC_LOCK_MSGQ) {
+
+    if (state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_PENDING_EXIT))
+	goto exiting;
+
+    if (!(*receiver_locks & ERTS_PROC_LOCK_MSGQ)) {
+	if (erts_smp_proc_trylock(receiver, ERTS_PROC_LOCK_MSGQ) == EBUSY) {
+	    ErtsProcLocks need_locks = ERTS_PROC_LOCK_MSGQ;
+	    if (*receiver_locks & ERTS_PROC_LOCK_STATUS) {
 		erts_smp_proc_unlock(receiver, ERTS_PROC_LOCK_STATUS);
-		need_locks = (ERTS_PROC_LOCK_MSGQ
-			      | ERTS_PROC_LOCK_STATUS);
+		need_locks |= ERTS_PROC_LOCK_STATUS;
 	    }
 	    erts_smp_proc_lock(receiver, need_locks);
 	}
+	locked_msgq = 1;
+	state = erts_smp_atomic32_read_nob(&receiver->state);
+	if (receiver_state)
+	    *receiver_state = state;
     }
 
-    if (ERTS_PROC_IS_EXITING(receiver) || ERTS_PROC_PENDING_EXIT(receiver)) {
-	/* Drop message if receiver is exiting or has a pending
-	 * exit ...
-	 */
+#endif
+
+    if (state & (ERTS_PSFLG_PENDING_EXIT|ERTS_PSFLG_EXITING)) {
+#ifdef ERTS_SMP
+    exiting:
+#endif
+	/* Drop message if receiver is exiting or has a pending exit... */
+	if (locked_msgq)
+	    erts_smp_proc_unlock(receiver, ERTS_PROC_LOCK_MSGQ);
 	if (bp)
 	    free_message_buffer(bp);
 	message_free(mp);
-	return;
+	return 0;
     }
-#endif
 
     ERL_MESSAGE_TERM(mp) = message;
     ERL_MESSAGE_TOKEN(mp) = seq_trace_token;
@@ -514,12 +505,11 @@ erts_queue_message(Process* receiver,
 	ERTS_SMP_MSGQ_MV_INQ2PRIVQ(receiver);
 	LINK_MESSAGE_PRIVQ(receiver, mp);
     }
-    else {
+    else
+#endif
+    {
 	LINK_MESSAGE(receiver, mp);
     }
-#else
-    LINK_MESSAGE(receiver, mp);
-#endif
 
 #ifdef USE_VM_PROBES
     if (DTRACE_ENABLED(message_queued)) {
@@ -539,15 +529,43 @@ erts_queue_message(Process* receiver,
                 tok_label, tok_lastcnt, tok_serial);
     }
 #endif
-    notify_new_message(receiver);
 
-    if (IS_TRACED_FL(receiver, F_TRACE_RECEIVE)) {
+    if (IS_TRACED_FL(receiver, F_TRACE_RECEIVE))
 	trace_receive(receiver, message);
-    }
+
+    if (locked_msgq)
+	erts_smp_proc_unlock(receiver, ERTS_PROC_LOCK_MSGQ);
+
+    erts_proc_notify_new_message(receiver);
 
 #ifndef ERTS_SMP
     ERTS_HOLE_CHECK(receiver);
 #endif
+    return 0;
+}
+
+void
+erts_queue_message(Process* receiver,
+		   ErtsProcLocks *receiver_locks,
+		   ErlHeapFragment* bp,
+		   Eterm message,
+		   Eterm seq_trace_token
+#ifdef USE_VM_PROBES
+		   , Eterm dt_utag
+#endif
+    )
+{
+    queue_message(NULL,
+		  receiver,
+		  receiver_locks,
+		  NULL,
+		  bp,
+		  message,
+		  seq_trace_token
+#ifdef USE_VM_PROBES
+		  , dt_utag
+#endif
+	);
 }
 
 void
@@ -1025,11 +1043,8 @@ erts_send_message(Process* sender,
 	LINK_MESSAGE(receiver, mp);
         ACTIVATE(receiver);
 
-        if (receiver->status == P_WAITING) {
-            erts_add_to_runq(receiver);
-        } else if (receiver->status == P_SUSPENDED) {
-            receiver->rstatus = P_RUNABLE;
-        }
+	erts_proc_notify_new_message(receiver);
+
         if (IS_TRACED_FL(receiver, F_TRACE_RECEIVE)) {
             trace_receive(receiver, message);
         }
@@ -1089,21 +1104,34 @@ erts_send_message(Process* sender,
 #ifdef ERTS_SMP
 	ErlOffHeap *ohp;
         Eterm *hp;
+	erts_aint32_t state;
+
 	BM_SWAP_TIMER(send,size);
 	msize = size_object(message);
 	BM_SWAP_TIMER(size,send);
-	hp = erts_alloc_message_heap(msize,&bp,&ohp,receiver,receiver_locks);
+	hp = erts_alloc_message_heap_state(msize,
+					   &bp,
+					   &ohp,
+					   receiver,
+					   receiver_locks,
+					   &state);
 	BM_SWAP_TIMER(send,copy);
 	message = copy_struct(message, msize, &hp, ohp);
 	BM_MESSAGE_COPIED(msz);
 	BM_SWAP_TIMER(copy,send);
         DTRACE6(message_send, sender_name, receiver_name,
                 msize, tok_label, tok_lastcnt, tok_serial);
-	erts_queue_message(receiver, receiver_locks, bp, message, token
+	queue_message(sender,
+		      receiver,
+		      receiver_locks,
+		      &state,
+		      bp,
+		      message,
+		      token
 #ifdef USE_VM_PROBES
-			   , NIL
+		      , NIL
 #endif
-			   );
+	    );
         BM_SWAP_TIMER(send,system);
 #else
 	ErlMessage* mp = message_alloc();
@@ -1134,17 +1162,13 @@ erts_send_message(Process* sender,
 	mp->data.attached = NULL;
 	LINK_MESSAGE(receiver, mp);
 
-	if (receiver->status == P_WAITING) {
-	    erts_add_to_runq(receiver);
-	} else if (receiver->status == P_SUSPENDED) {
-	    receiver->rstatus = P_RUNABLE;
-	}
+	erts_proc_notify_new_message(receiver);
+
 	if (IS_TRACED_FL(receiver, F_TRACE_RECEIVE)) {
 	    trace_receive(receiver, message);
 	}
         BM_SWAP_TIMER(send,system);
 #endif /* #ifndef ERTS_SMP */
-	return;
 #endif /* HYBRID */
     }
 }
diff --git a/erts/emulator/beam/erl_port_task.c b/erts/emulator/beam/erl_port_task.c
index 0f1a0d441a..86454fe1fa 100644
--- a/erts/emulator/beam/erl_port_task.c
+++ b/erts/emulator/beam/erl_port_task.c
@@ -56,12 +56,6 @@
 #define ERTS_PORT_IS_IN_RUNQ(RQ, P) \
   ((P)->sched.next || (P)->sched.prev || (RQ)->ports.start == (P))
 
-#define ERTS_PORT_NOT_IN_RUNQ(P)	\
-do {					\
-    (P)->sched.prev = NULL;		\
-    (P)->sched.next = NULL;		\
-} while (0)
-
 #ifdef USE_VM_PROBES
 #define DTRACE_DRIVER(PROBE_NAME, PP)                              \
     if (DTRACE_ENABLED(driver_ready_input)) {                      \
@@ -167,7 +161,7 @@ enqueue_port(ErtsRunQueue *runq, Port *pp)
 {
     ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(runq));
     pp->sched.next = NULL;
-    pp->sched.prev = runq->ports.end;
+    pp->sched.in_runq = 1;
     if (runq->ports.end) {
 	ASSERT(runq->ports.start);
 	runq->ports.end->sched.next = pp;
@@ -177,39 +171,10 @@ enqueue_port(ErtsRunQueue *runq, Port *pp)
 	runq->ports.start = pp;
     }
 
-    runq->ports.info.len++;
-    if (runq->ports.info.max_len < runq->ports.info.len)
-	runq->ports.info.max_len = runq->ports.info.len;
-    runq->len++;
-    if (runq->max_len < runq->len)
-	runq->max_len = runq->len;
     runq->ports.end = pp;
     ASSERT(runq->ports.start && runq->ports.end);
-}
 
-static ERTS_INLINE void
-dequeue_port(ErtsRunQueue *runq, Port *pp)
-{
-    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(runq));
-    if (pp->sched.next)
-	pp->sched.next->sched.prev = pp->sched.prev;
-    else {
-	ASSERT(runq->ports.end == pp);
-	runq->ports.end = pp->sched.prev;
-    }
-    if (pp->sched.prev)
-	pp->sched.prev->sched.next = pp->sched.next;
-    else {
-	ASSERT(runq->ports.start == pp);
-	runq->ports.start = pp->sched.next;
-    }
-
-    ASSERT(runq->ports.info.len > 0);
-    runq->ports.info.len--;
-    ASSERT(runq->len > 0);
-    runq->len--;
-    ASSERT(runq->ports.start || !runq->ports.end);
-    ASSERT(runq->ports.end || !runq->ports.start);
+    erts_smp_inc_runq_len(runq, &runq->ports.info, ERTS_PORT_PRIO_LEVEL);
 }
 
 static ERTS_INLINE Port *
@@ -222,16 +187,11 @@ pop_port(ErtsRunQueue *runq)
     }
     else {
 	runq->ports.start = runq->ports.start->sched.next;
-	if (runq->ports.start)
-	    runq->ports.start->sched.prev = NULL;
-	else {
+	if (!runq->ports.start) {
 	    ASSERT(runq->ports.end == pp);
 	    runq->ports.end = NULL;
 	}
-	ASSERT(runq->ports.info.len > 0);
-	runq->ports.info.len--;
-	ASSERT(runq->len > 0);
-	runq->len--;
+	erts_smp_dec_runq_len(runq, &runq->ports.info, ERTS_PORT_PRIO_LEVEL);
     }
 
     ASSERT(runq->ports.start || !runq->ports.end);
@@ -285,7 +245,7 @@ check_port_queue(ErtsRunQueue *runq, Port *chk_pp, int inq)
 	}
 	ASSERT(no_forward == no_backward);
     }
-    ASSERT(no_forward == runq->ports.info.len);
+    ASSERT(no_forward == RUNQ_READ_LEN(&runq->ports.info.len));
     if (chk_pp) {
 	if (chk_pp->sched.taskq || chk_pp->sched.exe_taskq) {
 	    ASSERT(chk_pp->sched.taskq != chk_pp->sched.exe_taskq);
@@ -467,10 +427,11 @@ erts_port_task_abort(Eterm id, ErtsPortTaskHandle *pthp)
     ErtsPortTaskQueue *ptqp;
     ErtsPortTask *ptp;
     Port *pp;
-    int port_is_dequeued = 0;
 
     pp = &erts_port[internal_port_index(id)];
     runq = erts_port_runq(pp);
+    if (!runq)
+	return 1;
 
     ptp = handle2task(pthp);
 
@@ -505,22 +466,12 @@ erts_port_task_abort(Eterm id, ErtsPortTaskHandle *pthp)
 
     if (ptqp->first || pp->sched.taskq != ptqp)
 	ptqp = NULL;
-    else {
+    else
 	pp->sched.taskq = NULL;
-	if (!pp->sched.exe_taskq) {
-	    dequeue_port(runq, pp);
-	    ERTS_PORT_NOT_IN_RUNQ(pp);
-	    port_is_dequeued = 1;
-	}
-    }
 
     ERTS_PT_CHK_PRES_PORTQ(runq, pp);
 
     erts_smp_runq_unlock(runq);
-    
-    if (erts_system_profile_flags.runnable_ports && port_is_dequeued) {
-    	profile_runnable_port(pp, am_inactive);
-    }
 
     port_task_free(ptp);
     if (ptqp)
@@ -575,7 +526,7 @@ erts_port_task_schedule(Eterm id,
 
     if (!pp->sched.taskq) {
 	pp->sched.taskq = port_taskq_init(port_taskq_alloc(), pp);
-	enq_port = !pp->sched.exe_taskq;
+	enq_port = !pp->sched.in_runq && !pp->sched.exe_taskq;
     }
 
 #ifdef ERTS_SMP
@@ -585,13 +536,13 @@ erts_port_task_schedule(Eterm id,
 	    /* Port emigrated ... */
 	    erts_smp_atomic_set_nob(&pp->run_queue, (erts_aint_t) xrunq);
 	    erts_smp_runq_unlock(runq);
-	    runq = xrunq;
+	    runq = erts_port_runq(pp);
+	    if (!runq)
+		return -1;
 	}
     }
 #endif
 
-    ASSERT(!enq_port || !(runq->flags & ERTS_RUNQ_FLG_SUSPENDED));
-
     ASSERT(pp->sched.taskq);
     ASSERT(ptp);
 
@@ -633,7 +584,7 @@ erts_port_task_schedule(Eterm id,
 #elif defined(DEBUG)
     if (!enq_port && !pp->sched.exe_taskq) {
 	/* We should be in port run q */
-	ASSERT(pp->sched.prev || runq->ports.start == pp);
+	ASSERT(pp->sched.in_runq);
     }
 #endif
 #endif
@@ -661,63 +612,54 @@ void
 erts_port_task_free_port(Port *pp)
 {
     ErtsRunQueue *runq;
-    int port_is_dequeued = 0;
+    ErtsPortTaskQueue *ptqp;
 
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(pp));
     ASSERT(!(pp->status & ERTS_PORT_SFLGS_DEAD));
     runq = erts_port_runq(pp);
     ASSERT(runq);
     ERTS_PT_CHK_PRES_PORTQ(runq, pp);
-    if (pp->sched.exe_taskq) {
+    ptqp = pp->sched.exe_taskq;
+    if (ptqp) {
 	/* I (this thread) am currently executing this port, free it
 	   when scheduled out... */
-	ErtsPortTask *ptp = port_task_alloc();
+	ErtsPortTask *ptp;
+    enqueue_free:
+	ptp = port_task_alloc();
 	erts_smp_port_state_lock(pp);
 	pp->status &= ~ERTS_PORT_SFLG_CLOSING;
 	pp->status |= ERTS_PORT_SFLG_FREE_SCHEDULED;
 	erts_may_save_closed_port(pp);
 	erts_smp_port_state_unlock(pp);
-	ERTS_SMP_LC_ASSERT(erts_smp_atomic_read_nob(&pp->refc) > 1);
+	ERTS_LC_ASSERT(erts_smp_atomic_read_nob(&pp->refc) > 1);
 	ptp->type = ERTS_PORT_TASK_FREE;
 	ptp->event = (ErlDrvEvent) -1;
 	ptp->event_data = NULL;
 	set_handle(ptp, NULL);
-	push_task(pp->sched.exe_taskq, ptp);
+	push_task(ptqp, ptp);
 	ERTS_PT_CHK_PRES_PORTQ(runq, pp);
 	erts_smp_runq_unlock(runq);
     }
     else {
-	ErtsPortTaskQueue *ptqp = pp->sched.taskq;
-	if (ptqp) {
-	    dequeue_port(runq, pp);
-	    ERTS_PORT_NOT_IN_RUNQ(pp);
-	    port_is_dequeued = 1;
+	if (pp->sched.in_runq) {
+	    ptqp = pp->sched.taskq;
+	    if (!ptqp)
+		pp->sched.taskq = ptqp = port_taskq_init(port_taskq_alloc(), pp);
+	    goto enqueue_free;
 	}
+	ASSERT(!pp->sched.taskq);
 	erts_smp_port_state_lock(pp);
 	pp->status &= ~ERTS_PORT_SFLG_CLOSING;
 	pp->status |= ERTS_PORT_SFLG_FREE_SCHEDULED;
 	erts_may_save_closed_port(pp);
 	erts_smp_port_state_unlock(pp);
-#ifdef ERTS_SMP
 	erts_smp_atomic_dec_nob(&pp->refc); /* Not alive */
-#endif
-	ERTS_SMP_LC_ASSERT(erts_smp_atomic_read_nob(&pp->refc) > 0); /* Lock */
+	ERTS_LC_ASSERT(erts_smp_atomic_read_nob(&pp->refc) > 0); /* Lock */
 	handle_remaining_tasks(runq, pp); /* May release runq lock */
 	ASSERT(!pp->sched.exe_taskq && (!ptqp || !ptqp->first));
 	pp->sched.taskq = NULL;
 	ERTS_PT_CHK_PRES_PORTQ(runq, pp);
-#ifndef ERTS_SMP
-	ASSERT(pp->status & ERTS_PORT_SFLG_PORT_DEBUG);
-	erts_port_status_set(pp, ERTS_PORT_SFLG_FREE);	
-#endif
 	erts_smp_runq_unlock(runq);
-
-	if (erts_system_profile_flags.runnable_ports && port_is_dequeued) {
-    	    profile_runnable_port(pp, am_inactive);
-    	}
-
-	if (ptqp)
-	    port_taskq_free(ptqp);
     }
 }
 
@@ -738,7 +680,6 @@ typedef struct {
 int
 erts_port_task_execute(ErtsRunQueue *runq, Port **curr_port_pp)
 {
-    int port_was_enqueued = 0;
     Port *pp;
     ErtsPortTaskQueue *ptqp;
     ErtsPortTask *ptp;
@@ -757,11 +698,18 @@ erts_port_task_execute(ErtsRunQueue *runq, Port **curr_port_pp)
 	goto done;
     }
 
-    ERTS_PORT_NOT_IN_RUNQ(pp);
+    ASSERT(pp->sched.in_runq);
+    pp->sched.in_runq = 0;
+    if (!pp->sched.taskq) {
+	if (erts_system_profile_flags.runnable_ports)
+	    profile_runnable_port(pp, am_inactive);
+	res = (erts_smp_atomic_read_nob(&erts_port_task_outstanding_io_tasks)
+	       != (erts_aint_t) 0);
+	goto done;
+    }
 
     *curr_port_pp = pp;
 
-    ASSERT(pp->sched.taskq);
     ASSERT(pp->sched.taskq->first);
     ptqp = pp->sched.taskq;
     pp->sched.taskq = NULL;
@@ -823,12 +771,8 @@ erts_port_task_execute(ErtsRunQueue *runq, Port **curr_port_pp)
 		handle_remaining_tasks(runq, pp);
 	    ASSERT(!ptqp->first
 		   && (!pp->sched.taskq || !pp->sched.taskq->first));
-#ifdef ERTS_SMP
 	    erts_smp_atomic_dec_nob(&pp->refc); /* Not alive */
-	    ERTS_SMP_LC_ASSERT(erts_smp_atomic_read_nob(&pp->refc) > 0); /* Lock */
-#else
-	    erts_port_status_bor_set(pp, ERTS_PORT_SFLG_FREE);	    
-#endif
+	    ERTS_LC_ASSERT(erts_smp_atomic_read_nob(&pp->refc) > 0); /* Lock */
 
 	    port_task_free(ptp);
 	    if (pp->sched.taskq)
@@ -918,6 +862,8 @@ erts_port_task_execute(ErtsRunQueue *runq, Port **curr_port_pp)
     if (!pp->sched.taskq) {
 	ASSERT(pp->sched.exe_taskq);
 	pp->sched.exe_taskq = NULL;
+	if (erts_system_profile_flags.runnable_ports)
+	    profile_runnable_port(pp, am_inactive);
     }
     else {
 #ifdef ERTS_SMP
@@ -940,14 +886,20 @@ erts_port_task_execute(ErtsRunQueue *runq, Port **curr_port_pp)
 	else {
 	    /* Port emigrated ... */
 	    erts_smp_atomic_set_nob(&pp->run_queue, (erts_aint_t) xrunq);
-	    enqueue_port(xrunq, pp);
-	    ASSERT(pp->sched.exe_taskq);
-	    pp->sched.exe_taskq = NULL;
-	    erts_smp_runq_unlock(xrunq);
-	    erts_smp_notify_inc_runq(xrunq);
+	    erts_smp_runq_unlock(runq);
+
+	    xrunq = erts_port_runq(pp);
+	    if (xrunq) {
+		enqueue_port(xrunq, pp);
+		ASSERT(pp->sched.exe_taskq);
+		pp->sched.exe_taskq = NULL;
+		erts_smp_runq_unlock(xrunq);
+		erts_smp_notify_inc_runq(xrunq);
+	    }
+
+	    erts_smp_runq_lock(runq);
 	}
 #endif
-	port_was_enqueued = 1;
     }
 
     res = (erts_smp_atomic_read_nob(&erts_port_task_outstanding_io_tasks)
@@ -957,10 +909,6 @@ erts_port_task_execute(ErtsRunQueue *runq, Port **curr_port_pp)
 
     port_taskq_free(ptqp);
 
-    if (erts_system_profile_flags.runnable_ports && (port_was_enqueued != 1)) {
-    	profile_runnable_port(pp, am_inactive);
-    }
-
     /* trace port scheduling, out */
     if (IS_TRACED_FL(pp, F_TRACE_SCHED_PORTS)) {
     	trace_sched_ports(pp, am_out);
@@ -1049,63 +997,33 @@ erts_port_is_scheduled(Port *pp)
 {
     int res;
     ErtsRunQueue *runq = erts_port_runq(pp);
+    if (!runq)
+	return 0;
     res = pp->sched.taskq || pp->sched.exe_taskq;
     erts_smp_runq_unlock(runq);
     return res;
 }
 
 #ifdef ERTS_SMP
+void
+erts_enqueue_port(ErtsRunQueue *rq, Port *pp)
+{
+    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(rq));
+    ASSERT(rq == (ErtsRunQueue *) erts_smp_atomic_read_nob(&pp->run_queue));
+    ASSERT(pp->sched.in_runq);
+    enqueue_port(rq, pp);
+}
 
-ErtsMigrateResult
-erts_port_migrate(Port *prt, int *prt_locked,
-		  ErtsRunQueue *from_rq, int *from_locked,
-		  ErtsRunQueue *to_rq, int *to_locked)
+Port *
+erts_dequeue_port(ErtsRunQueue *rq)
 {
-    ERTS_SMP_LC_ASSERT(*from_locked);
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(from_rq, *from_locked);
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(to_rq, *to_locked);
-
-    if (!*from_locked || !*to_locked) {
-	if (from_rq < to_rq) {
-	    if (!*to_locked) {
-		if (!*from_locked)
-		    erts_smp_runq_lock(from_rq);
-		erts_smp_runq_lock(to_rq);
-	    }
-	    else if (erts_smp_runq_trylock(from_rq) == EBUSY) {
-		erts_smp_runq_unlock(to_rq);
-		erts_smp_runq_lock(from_rq);
-		erts_smp_runq_lock(to_rq);
-	    }
-	}
-	else {
-	    if (!*from_locked) {
-		if (!*to_locked)
-		    erts_smp_runq_lock(to_rq);
-		erts_smp_runq_lock(from_rq);
-	    }
-	    else if (erts_smp_runq_trylock(to_rq) == EBUSY) {
-		erts_smp_runq_unlock(from_rq);
-		erts_smp_runq_lock(to_rq);
-		erts_smp_runq_lock(from_rq);
-	    }
-	}
-	*to_locked = *from_locked = 1;
-    }
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(from_rq, *from_locked);
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(to_rq, *to_locked);
-
-    /* Refuse to migrate to a suspended run queue */
-    if (to_rq->flags & ERTS_RUNQ_FLG_SUSPENDED)
-	return ERTS_MIGRATE_FAILED_RUNQ_SUSPENDED;
-    if (from_rq != (ErtsRunQueue *) erts_smp_atomic_read_nob(&prt->run_queue))
-	return ERTS_MIGRATE_FAILED_RUNQ_CHANGED;
-    if (!ERTS_PORT_IS_IN_RUNQ(from_rq, prt))
-	return ERTS_MIGRATE_FAILED_NOT_IN_RUNQ;
-    dequeue_port(from_rq, prt);
-    erts_smp_atomic_set_nob(&prt->run_queue, (erts_aint_t) to_rq);
-    enqueue_port(to_rq, prt);
-    return ERTS_MIGRATE_SUCCESS;
+    Port *pp;
+    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(rq));
+    pp = pop_port(rq);
+    ASSERT(!pp
+	   || rq == (ErtsRunQueue *) erts_smp_atomic_read_nob(&pp->run_queue));
+    ASSERT(!pp || pp->sched.in_runq);
+    return pp;
 }
 
 #endif
diff --git a/erts/emulator/beam/erl_port_task.h b/erts/emulator/beam/erl_port_task.h
index d7104e1143..fd88b1c1ff 100644
--- a/erts/emulator/beam/erl_port_task.h
+++ b/erts/emulator/beam/erl_port_task.h
@@ -62,7 +62,7 @@ typedef struct ErtsPortTaskQueue_ ErtsPortTaskQueue;
 
 typedef struct {
     Port *next;
-    Port *prev;
+    int in_runq;
     ErtsPortTaskQueue *taskq;
     ErtsPortTaskQueue *exe_taskq;
 } ErtsPortTaskSched;
@@ -92,7 +92,7 @@ ERTS_GLB_INLINE void
 erts_port_task_init_sched(ErtsPortTaskSched *ptsp)
 {
     ptsp->next = NULL;
-    ptsp->prev = NULL;
+    ptsp->in_runq = 0;
     ptsp->taskq = NULL;
     ptsp->exe_taskq = NULL;
 }
@@ -123,13 +123,10 @@ int erts_port_task_schedule(Eterm,
 			    ErlDrvEventData);
 void erts_port_task_free_port(Port *);
 int erts_port_is_scheduled(Port *);
+
 #ifdef ERTS_SMP
-ErtsMigrateResult erts_port_migrate(Port *,
-				    int *,
-				    ErtsRunQueue *,
-				    int *,
-				    ErtsRunQueue *,
-				    int *);
+void erts_enqueue_port(ErtsRunQueue *rq, Port *pp);
+Port *erts_dequeue_port(ErtsRunQueue *rq);
 #endif
 #undef ERTS_INCLUDE_SCHEDULER_INTERNALS
 #endif /* ERL_PORT_TASK_H__ */
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 7174991ade..ba46b9011d 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -94,12 +94,44 @@
 #define HIGH_BIT      (1 << PRIORITY_HIGH)
 #define NORMAL_BIT    (1 << PRIORITY_NORMAL)
 #define LOW_BIT       (1 << PRIORITY_LOW)
+#define PORT_BIT      (1 << ERTS_PORT_PRIO_LEVEL)
 
-#define ERTS_EMPTY_RUNQ(RQ) \
-  ((RQ)->len == 0 && (RQ)->misc.start == NULL)
+#define ERTS_EMPTY_RUNQ(RQ)					\
+    ((ERTS_RUNQ_FLGS_GET_NOB((RQ)) & ERTS_RUNQ_FLGS_QMASK) == 0	\
+     && (RQ)->misc.start == NULL)
+
+#undef RUNQ_READ_RQ
+#undef RUNQ_SET_RQ
+#define RUNQ_READ_RQ(X) ((ErtsRunQueue *) erts_smp_atomic_read_nob((X)))
+#define RUNQ_SET_RQ(X, RQ) erts_smp_atomic_set_nob((X), (erts_aint_t) (RQ))
+
+#ifdef DEBUG
+#  if defined(ARCH_64) && !HALFWORD_HEAP
+#    define ERTS_DBG_SET_INVALID_RUNQP(RQP, N) \
+    (RUNQ_SET_RQ((RQP), (0xdeadbeefdead0003LL | ((N) << 4)))
+#  define ERTS_DBG_VERIFY_VALID_RUNQP(RQP) \
+do { \
+    ASSERT((RQP) != NULL); \
+    ASSERT(((((Uint) (RQP)) & ((Uint) 0x3))) == ((Uint) 0)); \
+    ASSERT((((Uint) (RQP)) & ~((Uint) 0xffff)) != ((Uint) 0xdeadbeefdead0000LL));\
+} while (0)
+#  else
+#    define ERTS_DBG_SET_INVALID_RUNQP(RQP, N) \
+    (RUNQ_SET_RQ((RQP), (0xdead0003 | ((N) << 4))))
+#  define ERTS_DBG_VERIFY_VALID_RUNQP(RQP) \
+do { \
+    ASSERT((RQP) != NULL); \
+    ASSERT(((((UWord) (RQP)) & ((UWord) 1))) == ((UWord) 0)); \
+    ASSERT((((UWord) (RQP)) & ~((UWord) 0xffff)) != ((UWord) 0xdead0000)); \
+} while (0)
+#  endif
+#else
+#  define ERTS_DBG_SET_INVALID_RUNQP(RQP, N)
+#  define ERTS_DBG_VERIFY_VALID_RUNQP(RQP)
+#endif
 
 #define ERTS_EMPTY_RUNQ_PORTS(RQ) \
-  ((RQ)->ports.info.len == 0 && (RQ)->misc.start == NULL)
+    (RUNQ_READ_LEN(&(RQ)->ports.info.len) == 0 && (RQ)->misc.start == NULL)
 
 extern BeamInstr beam_apply[];
 extern BeamInstr beam_exit[];
@@ -312,7 +344,7 @@ static struct {
     struct {
 	int active_runqs;
 	int reds;
-	int max_len;
+	erts_aint32_t max_len;
     } prev_rise;
     Uint n;
 } balance_info;
@@ -1884,8 +1916,8 @@ sched_waiting_sys(Uint no, ErtsRunQueue *rq)
 {
     ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(rq));
     ASSERT(rq->waiting >= 0);
-    rq->flags |= (ERTS_RUNQ_FLG_OUT_OF_WORK
-		  | ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK);
+    ERTS_RUNQ_FLGS_SET(rq, (ERTS_RUNQ_FLG_OUT_OF_WORK
+			    | ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK));
     rq->waiting++;
     rq->waiting *= -1;
     rq->woken = 0;
@@ -1961,8 +1993,8 @@ static ERTS_INLINE void
 sched_waiting(Uint no, ErtsRunQueue *rq)
 {
     ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(rq));
-    rq->flags |= (ERTS_RUNQ_FLG_OUT_OF_WORK
-		  | ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK);
+    ERTS_RUNQ_FLGS_SET(rq, (ERTS_RUNQ_FLG_OUT_OF_WORK
+			    | ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK));
     if (rq->waiting < 0)
 	rq->waiting--;
     else
@@ -1994,9 +2026,8 @@ ongoing_multi_scheduling_block(void)
 static ERTS_INLINE void
 empty_runq(ErtsRunQueue *rq)
 {
-    erts_aint32_t oifls = erts_smp_atomic32_read_band_nob(&rq->info_flags,
-							  ~ERTS_RUNQ_IFLG_NONEMPTY);
-    if (oifls & ERTS_RUNQ_IFLG_NONEMPTY) {
+    Uint32 old_flags = ERTS_RUNQ_FLGS_UNSET(rq, ERTS_RUNQ_FLG_NONEMPTY|ERTS_RUNQ_FLG_PROTECTED);
+    if (old_flags & ERTS_RUNQ_FLG_NONEMPTY) {
 #ifdef DEBUG
 	erts_aint32_t empty = erts_smp_atomic32_read_nob(&no_empty_run_queues);
 	/*
@@ -2012,9 +2043,8 @@ empty_runq(ErtsRunQueue *rq)
 static ERTS_INLINE void
 non_empty_runq(ErtsRunQueue *rq)
 {
-    erts_aint32_t oifls = erts_smp_atomic32_read_bor_nob(&rq->info_flags,
-							 ERTS_RUNQ_IFLG_NONEMPTY);
-    if (!(oifls & ERTS_RUNQ_IFLG_NONEMPTY)) {
+    Uint32 old_flags = ERTS_RUNQ_FLGS_SET(rq, ERTS_RUNQ_FLG_NONEMPTY);
+    if (!(old_flags & ERTS_RUNQ_FLG_NONEMPTY)) {
 #ifdef DEBUG
 	erts_aint32_t empty = erts_smp_atomic32_read_nob(&no_empty_run_queues);
 	/*
@@ -2627,19 +2657,16 @@ try_inc_no_active_runqs(int active)
 static ERTS_INLINE int
 chk_wake_sched(ErtsRunQueue *crq, int ix, int activate)
 {
-    erts_aint32_t iflgs;
+    Uint32 flags;
     ErtsRunQueue *wrq;
     if (crq->ix == ix)
 	return 0;
     wrq = ERTS_RUNQ_IX(ix);
-    iflgs = erts_smp_atomic32_read_nob(&wrq->info_flags);
-    if (!(iflgs & (ERTS_RUNQ_IFLG_SUSPENDED|ERTS_RUNQ_IFLG_NONEMPTY))) {
+    flags = ERTS_RUNQ_FLGS_GET(wrq);
+    if (!(flags & (ERTS_RUNQ_FLG_SUSPENDED|ERTS_RUNQ_FLG_NONEMPTY))) {
 	if (activate) {
-	    if (try_inc_no_active_runqs(ix+1)) {
-		erts_smp_xrunq_lock(crq, wrq);
-		wrq->flags &= ~ERTS_RUNQ_FLG_INACTIVE;
-		erts_smp_xrunq_unlock(crq, wrq);
-	    }
+	    if (try_inc_no_active_runqs(ix+1))
+		ERTS_RUNQ_FLGS_UNSET(wrq, ERTS_RUNQ_FLG_INACTIVE);
 	}
 	wake_scheduler(wrq, 0);
 	return 1;
@@ -2706,9 +2733,7 @@ erts_sched_notify_check_cpu_bind(void)
     int ix;
     for (ix = 0; ix < erts_no_run_queues; ix++) {
 	ErtsRunQueue *rq = ERTS_RUNQ_IX(ix);
-	erts_smp_runq_lock(rq);
-	rq->flags |= ERTS_RUNQ_FLG_CHK_CPU_BIND;
-	erts_smp_runq_unlock(rq);
+	ERTS_RUNQ_FLGS_SET(rq, ERTS_RUNQ_FLG_CHK_CPU_BIND);
 	wake_scheduler(rq, 0);
     }
 #else
@@ -2717,409 +2742,547 @@ erts_sched_notify_check_cpu_bind(void)
 }
 
 
-#ifdef ERTS_SMP
+static ERTS_INLINE void
+enqueue_process(ErtsRunQueue *runq, int prio, Process *p)
+{
+    ErtsRunPrioQueue *rpq;
 
-ErtsRunQueue *
-erts_prepare_emigrate(ErtsRunQueue *c_rq, ErtsRunQueueInfo *c_rqi, int prio)
+    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(runq));
+
+    erts_smp_inc_runq_len(runq, &runq->procs.prio_info[prio], prio);
+
+    if (prio == PRIORITY_LOW) {
+	p->schedule_count = RESCHEDULE_LOW;
+	rpq = &runq->procs.prio[PRIORITY_NORMAL];
+    }
+    else {
+	p->schedule_count = 1;
+	rpq = &runq->procs.prio[prio];
+    }
+
+    p->next = NULL;
+    if (rpq->last)
+	rpq->last->next = p;
+    else
+	rpq->first = p;
+    rpq->last = p;
+}
+
+
+static ERTS_INLINE void
+unqueue_process(ErtsRunQueue *runq,
+		ErtsRunPrioQueue *rpq,
+		ErtsRunQueueInfo *rqi,
+		int prio,
+		Process *prev_proc,
+		Process *proc)
 {
-    ASSERT(ERTS_CHK_RUNQ_FLG_EMIGRATE(c_rq->flags, prio));
-    ASSERT(ERTS_CHK_RUNQ_FLG_EVACUATE(c_rq->flags, prio)
-	   || c_rqi->len >= c_rqi->migrate.limit.this);
+    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(runq));
 
-    while (1) {
-	ErtsRunQueue *n_rq = c_rqi->migrate.runq;
-	ERTS_DBG_VERIFY_VALID_RUNQP(n_rq);
-	erts_smp_xrunq_lock(c_rq, n_rq);
-	    
-	/*
-	 * erts_smp_xrunq_lock() may release lock on c_rq! We have
-	 * to check that we still want to emigrate and emigrate
-	 * to the same run queue as before.
-	 */
+    if (prev_proc)
+	prev_proc->next = proc->next;
+    else
+	rpq->first = proc->next;
+    if (!proc->next)
+	rpq->last = prev_proc;
 
-	if (ERTS_CHK_RUNQ_FLG_EMIGRATE(c_rq->flags, prio)) {
-	    Uint32 force = (ERTS_CHK_RUNQ_FLG_EVACUATE(c_rq->flags, prio)
-			    | (c_rq->flags & ERTS_RUNQ_FLG_INACTIVE));
-	    if (force || c_rqi->len > c_rqi->migrate.limit.this) {
-		ErtsRunQueueInfo *n_rqi;
-		/* We still want to emigrate */
-
-		if (n_rq != c_rqi->migrate.runq) {
-		    /* Ahh... run queue changed; need to do it all over again... */
-		    erts_smp_runq_unlock(n_rq);
-		    continue;
-		}
-		else {
+    if (!rpq->first)
+	rpq->last = NULL;
 
-		    if (prio == ERTS_PORT_PRIO_LEVEL)
-			n_rqi = &n_rq->ports.info;
-		    else
-			n_rqi = &n_rq->procs.prio_info[prio];
+    erts_smp_dec_runq_len(runq, rqi, prio);
+}
 
-		    if (force || (n_rqi->len < c_rqi->migrate.limit.other)) {
-			/* emigrate ... */
-			return n_rq;
-		    }
-		}
-	    }
-	}
 
-	ASSERT(n_rq != c_rq);
-	erts_smp_runq_unlock(n_rq);
-	if (!(c_rq->flags & ERTS_RUNQ_FLG_INACTIVE)) {
-	    /* No more emigrations to this runq */
-	    ERTS_UNSET_RUNQ_FLG_EMIGRATE(c_rq->flags, prio);
-	    ERTS_DBG_SET_INVALID_RUNQP(c_rqi->migrate.runq, 0x3);
-	}
+static ERTS_INLINE Process *
+dequeue_process(ErtsRunQueue *runq, int prio_q, erts_aint32_t *statep)
+{
+    erts_aint32_t state;
+    int prio;
+    ErtsRunPrioQueue *rpq;
+    ErtsRunQueueInfo *rqi;
+    Process *p;
+
+    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(runq));
+
+    ASSERT(PRIORITY_NORMAL == prio_q
+	   || PRIORITY_HIGH == prio_q
+	   || PRIORITY_MAX == prio_q);
 
+    rpq = &runq->procs.prio[prio_q];
+    p = rpq->first;
+    if (!p)
 	return NULL;
+
+    ERTS_SMP_DATA_DEPENDENCY_READ_MEMORY_BARRIER;
+
+    state = erts_smp_atomic32_read_nob(&p->state);
+    if (statep)
+	*statep = state;
+
+    prio = (int) (ERTS_PSFLG_PRIO_MASK & state);
+
+    rqi = &runq->procs.prio_info[prio];
+
+    if (p)
+	unqueue_process(runq, rpq, rqi, prio, NULL, p);
+
+    return p;
+}
+
+static ERTS_INLINE int
+check_requeue_process(ErtsRunQueue *rq, int prio_q)
+{
+    ErtsRunPrioQueue *rpq = &rq->procs.prio[prio_q];
+    Process *p = rpq->first;
+    if (--p->schedule_count > 0 && p != rpq->last) {
+	/* reschedule */
+	rpq->first = p->next;
+	rpq->last->next = p;
+	rpq->last = p;
+	p->next = NULL;
+	return 1;
+    }
+    return 0;
+}
+
+#ifdef ERTS_SMP
+
+static ErtsRunQueue *
+check_immigration_need(ErtsRunQueue *c_rq, ErtsMigrationPath *mp, int prio)
+{
+    int len;
+    Uint32 f_flags, f_rq_flags;
+    ErtsRunQueue *f_rq;
+
+    f_flags = mp->prio[prio].flags;
+
+    ASSERT(ERTS_CHK_RUNQ_FLG_IMMIGRATE(mp->flags, prio));
+
+    f_rq = mp->prio[prio].runq;
+    if (!f_rq)
+	return NULL;
+
+    f_rq_flags = ERTS_RUNQ_FLGS_GET(f_rq);
+    if (f_rq_flags & ERTS_RUNQ_FLG_PROTECTED)
+	return NULL;
+
+    if (ERTS_CHK_RUNQ_FLG_EVACUATE(f_flags, prio))
+	return f_rq;
+
+    if (f_rq_flags & ERTS_RUNQ_FLG_INACTIVE)
+	return f_rq;
+
+    if (prio == ERTS_PORT_PRIO_LEVEL)
+	len = RUNQ_READ_LEN(&c_rq->ports.info.len);
+    else
+	len = RUNQ_READ_LEN(&c_rq->procs.prio_info[prio].len);
+
+    if (len < mp->prio[prio].limit.this) {
+	if (prio == ERTS_PORT_PRIO_LEVEL)
+	    len = RUNQ_READ_LEN(&f_rq->ports.info.len);
+	else
+	    len = RUNQ_READ_LEN(&f_rq->procs.prio_info[prio].len);
+
+	if (len > mp->prio[prio].limit.other)
+	    return f_rq;
     }
+    return NULL;
 }
 
 static void
-immigrate(ErtsRunQueue *rq)
+immigrate(ErtsRunQueue *c_rq, ErtsMigrationPath *mp)
 {
-    int prio;
+    Uint32 iflags, iflag;
+    erts_smp_runq_unlock(c_rq);
 
-    ASSERT(rq->flags & ERTS_RUNQ_FLGS_IMMIGRATE_QMASK);
+    ASSERT(erts_thr_progress_is_managed_thread());
 
-    for (prio = 0; prio < ERTS_NO_PRIO_LEVELS; prio++) {
-	if (ERTS_CHK_RUNQ_FLG_IMMIGRATE(rq->flags, prio)) {
-	    ErtsRunQueueInfo *rqi = (prio == ERTS_PORT_PRIO_LEVEL
-				     ? &rq->ports.info
-				     : &rq->procs.prio_info[prio]);
-	    ErtsRunQueue *from_rq = rqi->migrate.runq;
-	    int rq_locked, from_rq_locked;
+    iflags = mp->flags & ERTS_RUNQ_FLGS_IMMIGRATE_QMASK;
 
-	    ERTS_DBG_VERIFY_VALID_RUNQP(from_rq);
+    iflag = iflags & -iflags;
 
-	    rq_locked = 1;
-	    from_rq_locked = 1;
-	    erts_smp_xrunq_lock(rq, from_rq);
-	    /*
-	     * erts_smp_xrunq_lock() may release lock on rq! We have
-	     * to check that we still want to immigrate from the same 
-	     * run queue as before.
-	     */
-	    if (ERTS_CHK_RUNQ_FLG_IMMIGRATE(rq->flags, prio)
-		&& from_rq == rqi->migrate.runq) {
-		ErtsRunQueueInfo *from_rqi = (prio == ERTS_PORT_PRIO_LEVEL
-					      ? &from_rq->ports.info
-					      : &from_rq->procs.prio_info[prio]);
-		if ((ERTS_CHK_RUNQ_FLG_EVACUATE(rq->flags, prio)
-		     && ERTS_CHK_RUNQ_FLG_EVACUATE(from_rq->flags, prio)
-		     && from_rqi->len)
-		    || (from_rqi->len > rqi->migrate.limit.other
-			&& rqi->len < rqi->migrate.limit.this)) {
-		    if (prio == ERTS_PORT_PRIO_LEVEL) {
-			Port *prt = from_rq->ports.start;
-			if (prt) {
-			    int prt_locked = 0;
-			    (void) erts_port_migrate(prt, &prt_locked,
-						     from_rq, &from_rq_locked,
-						     rq, &rq_locked);
-			    if (prt_locked)
-				erts_smp_port_unlock(prt);
-			}
-		    }
-		    else {
-			Process *proc;
-			ErtsRunPrioQueue *from_rpq;
-			from_rpq = (prio == PRIORITY_LOW
-				    ? &from_rq->procs.prio[PRIORITY_NORMAL]
-				    : &from_rq->procs.prio[prio]);
-			for (proc = from_rpq->first; proc; proc = proc->next)
-			    if (proc->prio == prio && !proc->bound_runq)
-				break;
-			if (proc) {
-			    ErtsProcLocks proc_locks = 0;
-			    (void) erts_proc_migrate(proc, &proc_locks,
-						     from_rq, &from_rq_locked,
-						     rq, &rq_locked);
-			    if (proc_locks)
-				erts_smp_proc_unlock(proc, proc_locks);
-			}
+    while (iflag) {
+	ErtsRunQueue *rq;
+	int prio;
+
+	switch (iflag) {
+	case (MAX_BIT << ERTS_RUNQ_FLGS_IMMIGRATE_SHFT):
+	    prio = PRIORITY_MAX;
+	    break;
+	case (HIGH_BIT << ERTS_RUNQ_FLGS_IMMIGRATE_SHFT):
+	    prio = PRIORITY_HIGH;
+	    break;
+	case (NORMAL_BIT << ERTS_RUNQ_FLGS_IMMIGRATE_SHFT):
+	    prio = PRIORITY_NORMAL;
+	    break;
+	case (LOW_BIT << ERTS_RUNQ_FLGS_IMMIGRATE_SHFT):
+	    prio = PRIORITY_LOW;
+	    break;
+	case (PORT_BIT << ERTS_RUNQ_FLGS_IMMIGRATE_SHFT):
+	    prio = ERTS_PORT_PRIO_LEVEL;
+	    break;
+	default:
+	    erl_exit(ERTS_ABORT_EXIT,
+		     "%s:%d:%s(): Invalid immigrate queue mask",
+		     __FILE__, __LINE__, __func__);
+	    prio = 0;
+	    break;
+	}
+
+	iflags &= ~iflag;
+	iflag = iflags & -iflags;
+
+	rq = check_immigration_need(c_rq, mp, prio);
+	if (rq) {
+	    erts_smp_runq_lock(rq);
+	    if (prio == ERTS_PORT_PRIO_LEVEL) {
+		Port *prt;
+		prt = erts_dequeue_port(rq);
+		if (prt)
+		    RUNQ_SET_RQ(&prt->run_queue, c_rq);
+		erts_smp_runq_unlock(rq);
+		if (prt) {
+		    /* port might terminate while we have no lock... */
+		    rq = erts_port_runq(prt);
+		    if (rq) {
+			if (rq != c_rq)
+			    erl_exit(ERTS_ABORT_EXIT,
+				     "%s:%d:%s(): Internal error",
+				     __FILE__, __LINE__, __func__);
+			erts_enqueue_port(c_rq, prt);
+			if (!iflag)
+			    return; /* done */
+			erts_smp_runq_unlock(c_rq);
 		    }
 		}
-		else {
-		    ERTS_UNSET_RUNQ_FLG_IMMIGRATE(rq->flags, prio);
-		    ERTS_DBG_SET_INVALID_RUNQP(rqi->migrate.runq, 0x1);
+	    }
+	    else {
+		ErtsRunPrioQueue *rpq = &rq->procs.prio[prio == PRIORITY_LOW
+							? PRIORITY_NORMAL
+							: prio];
+		Process *prev_proc = NULL;
+		Process *proc = rpq->first;
+		int rq_locked = 1;
+
+		while (proc) {
+		    erts_aint32_t state;
+		    state = erts_smp_atomic32_read_acqb(&proc->state);
+		    if (!(ERTS_PSFLG_BOUND & state)
+			&& (prio == (int) (ERTS_PSFLG_PRIO_MASK & state))) {
+			ErtsRunQueueInfo *rqi = &rq->procs.prio_info[prio];
+			unqueue_process(rq, rpq, rqi, prio, prev_proc, proc);
+			erts_smp_runq_unlock(rq);
+			RUNQ_SET_RQ(&proc->run_queue, c_rq);
+			rq_locked = 0;
+
+			erts_smp_runq_lock(c_rq);
+			enqueue_process(c_rq, prio, proc);
+			if (!iflag)
+			    return; /* done */
+			erts_smp_runq_unlock(c_rq);
+			break;
+		    }
+		    prev_proc = proc;
+		    proc = proc->next;
 		}
+		if (rq_locked)
+		    erts_smp_runq_unlock(rq);
 	    }
-	    if (from_rq_locked)
-		erts_smp_runq_unlock(from_rq);
-	    if (!rq_locked)
-		erts_smp_runq_lock(rq);
 	}
     }
+
+    erts_smp_runq_lock(c_rq);
+}
+
+static ERTS_INLINE void
+suspend_run_queue(ErtsRunQueue *rq)
+{
+    erts_smp_atomic32_read_bor_nob(&rq->scheduler->ssi->flags,
+				   ERTS_SSI_FLG_SUSPENDED);
+    ERTS_RUNQ_FLGS_SET(rq, ERTS_RUNQ_FLG_SUSPENDED);
+
+    wake_scheduler(rq, 0);
+}
+
+static void scheduler_ix_resume_wake(Uint ix);
+
+static ERTS_INLINE void
+resume_run_queue(ErtsRunQueue *rq)
+{
+    int pix;
+
+    erts_smp_runq_lock(rq);
+
+    (void) ERTS_RUNQ_FLGS_MASK_SET(rq,
+				   (ERTS_RUNQ_FLG_OUT_OF_WORK
+				    | ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK
+				    | ERTS_RUNQ_FLG_SUSPENDED),
+				   (ERTS_RUNQ_FLG_OUT_OF_WORK
+				    | ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK));
+
+    rq->check_balance_reds = ERTS_RUNQ_CALL_CHECK_BALANCE_REDS;
+    for (pix = 0; pix < ERTS_NO_PROC_PRIO_LEVELS; pix++) {
+	rq->procs.prio_info[pix].max_len = 0;
+	rq->procs.prio_info[pix].reds = 0;
+    }
+    rq->ports.info.max_len = 0;
+    rq->ports.info.reds = 0;
+    rq->max_len = 0;
+
+    erts_smp_runq_unlock(rq);
+
+    scheduler_ix_resume_wake(rq->ix);
 }
 
+typedef struct {
+    Process *first;
+    Process *last;
+} ErtsStuckBoundProcesses;
+
 static void
-evacuate_run_queue(ErtsRunQueue *evac_rq, ErtsRunQueue *rq)
+schedule_bound_processes(ErtsRunQueue *rq,
+			 ErtsStuckBoundProcesses *sbpp)
 {
-    Port *prt;
-    int notify_to_rq = 0;
-    int prio;
-    int prt_locked = 0;
-    int rq_locked = 0;
-    int evac_rq_locked = 1;
-    ErtsMigrateResult mres;
+    Process *proc, *next;
+    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(rq));
+
+    proc = sbpp->first;
+    while (proc) {
+	erts_aint32_t state = erts_smp_atomic32_read_acqb(&proc->state);
+	next = proc->next;
+	enqueue_process(rq, (int) (ERTS_PSFLG_PRIO_MASK & state), proc);
+	proc = next;
+    }
+}
 
-    erts_smp_runq_lock(evac_rq);
+static void
+evacuate_run_queue(ErtsRunQueue *rq,
+		   ErtsStuckBoundProcesses *sbpp)
+{
+    int prio_q;
+    ErtsRunQueue *to_rq;
+    ErtsMigrationPaths *mps;
+    ErtsMigrationPath *mp;
 
-    erts_smp_atomic32_read_bor_nob(&evac_rq->scheduler->ssi->flags,
-				   ERTS_SSI_FLG_SUSPENDED);
+    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(rq));
 
-    evac_rq->flags &= ~ERTS_RUNQ_FLGS_IMMIGRATE_QMASK;
-    evac_rq->flags |= (ERTS_RUNQ_FLGS_EMIGRATE_QMASK
-		       | ERTS_RUNQ_FLGS_EVACUATE_QMASK
-		       | ERTS_RUNQ_FLG_SUSPENDED);
+    ERTS_RUNQ_FLGS_UNSET(rq, ERTS_RUNQ_FLG_PROTECTED);
 
-    erts_smp_atomic32_read_bor_nob(&evac_rq->info_flags, ERTS_RUNQ_IFLG_SUSPENDED);
-    /*
-     * Need to set up evacuation paths first since we
-     * may release the run queue lock on evac_rq
-     * when evacuating.
-     */
-    evac_rq->misc.evac_runq = rq;
-    evac_rq->ports.info.migrate.runq = rq;
-    for (prio = 0; prio < ERTS_NO_PROC_PRIO_LEVELS; prio++)
-	evac_rq->procs.prio_info[prio].migrate.runq = rq;
+    mps = erts_get_migration_paths_managed();
+    mp = &mps->mpath[rq->ix];
 
     /* Evacuate scheduled misc ops */
 
-    if (evac_rq->misc.start) {
-	rq_locked = 1;
-	erts_smp_xrunq_lock(evac_rq, rq);
-	if (rq->misc.end)
-	    rq->misc.end->next = evac_rq->misc.start;
+    if (rq->misc.start) {
+	ErtsMiscOpList *start, *end;
+
+	to_rq = mp->misc_evac_runq;
+	if (!to_rq)
+	    return;
+
+	start = rq->misc.start;
+	end = rq->misc.end;
+	rq->misc.start = NULL;
+	rq->misc.end = NULL;
+	erts_smp_runq_unlock(rq);
+
+	erts_smp_runq_lock(to_rq);
+	if (to_rq->misc.end)
+	    to_rq->misc.end->next = start;
 	else
-	    rq->misc.start = evac_rq->misc.start;
-	rq->misc.end = evac_rq->misc.end;
-	evac_rq->misc.start = NULL;
-	evac_rq->misc.end = NULL;
+	    to_rq->misc.start = start;
+
+	to_rq->misc.end = end;
+	erts_smp_runq_unlock(to_rq);
+	smp_notify_inc_runq(to_rq);
+	erts_smp_runq_lock(to_rq);
     }
 
-    /* Evacuate scheduled ports */
-    prt = evac_rq->ports.start;
-    while (prt) {
-	mres = erts_port_migrate(prt, &prt_locked,
-				 evac_rq, &evac_rq_locked,
-				 rq, &rq_locked);
-	if (mres == ERTS_MIGRATE_SUCCESS)
-	    notify_to_rq = 1;
-	if (prt_locked)
-	    erts_smp_port_unlock(prt);
-	if (!evac_rq_locked) {
-	    evac_rq_locked = 1;
-	    erts_smp_runq_lock(evac_rq);
+    if (rq->ports.start) {
+	Port *prt;
+
+	to_rq = mp->prio[ERTS_PORT_PRIO_LEVEL].runq;
+	if (!to_rq)
+	    return;
+
+	/* Evacuate scheduled ports */
+	prt = rq->ports.start;
+	while (prt) {
+	    ErtsRunQueue *prt_rq;
+	    prt = erts_dequeue_port(rq);
+	    RUNQ_SET_RQ(&prt->run_queue, to_rq);
+	    erts_smp_runq_unlock(rq);
+	    /*
+	     * The port might terminate while
+	     * we have no lock on it...
+	     */
+	    prt_rq = erts_port_runq(prt);
+	    if (prt_rq) {
+		if (prt_rq != to_rq)
+		    erl_exit(ERTS_ABORT_EXIT,
+			     "%s:%d:%s() internal error\n",
+			     __FILE__, __LINE__, __func__);
+		erts_enqueue_port(to_rq, prt);
+		erts_smp_runq_unlock(to_rq);
+	    }
+	    erts_smp_runq_lock(rq);
+	    prt = rq->ports.start;
 	}
-	prt = evac_rq->ports.start;
+	smp_notify_inc_runq(to_rq);
     }
 
     /* Evacuate scheduled processes */
-    for (prio = 0; prio < ERTS_NO_PROC_PRIO_LEVELS; prio++) {
+    for (prio_q = 0; prio_q < ERTS_NO_PROC_PRIO_QUEUES; prio_q++) {
+	erts_aint32_t state;
 	Process *proc;
+	int notify = 0;
+	to_rq = NULL;
 
-	switch (prio) {
-	case PRIORITY_MAX:
-	case PRIORITY_HIGH:
-	case PRIORITY_NORMAL:
-	    proc = evac_rq->procs.prio[prio].first;
-	    while (proc) {
-		ErtsProcLocks proc_locks = 0;
-
-		/* Bound processes are stuck... */
-		while (proc->bound_runq) {
-		    proc = proc->next;
-		    if (!proc)
-			goto end_of_proc;
-		}
-
-		mres = erts_proc_migrate(proc, &proc_locks,
-					 evac_rq, &evac_rq_locked,
-					 rq, &rq_locked);
-		if (mres == ERTS_MIGRATE_SUCCESS)
-		    notify_to_rq = 1;
-		if (proc_locks)
-		    erts_smp_proc_unlock(proc, proc_locks);
-		if (!evac_rq_locked) {
-		    erts_smp_runq_lock(evac_rq);
-		    evac_rq_locked = 1;
-		}
+	if (!mp->prio[prio_q].runq)
+	    return;
+	if (prio_q == PRIORITY_NORMAL && !mp->prio[PRIORITY_LOW].runq)
+	    return;
 
-		proc = evac_rq->procs.prio[prio].first;
+	proc = dequeue_process(rq, prio_q, &state);
+	while (proc) {
+	    if (ERTS_PSFLG_BOUND & state) {
+		/* Bound processes get stuck here... */
+		proc->next = NULL;
+		if (sbpp->last)
+		    sbpp->last->next = proc;
+		else
+		    sbpp->first = proc;
+		sbpp->last = proc;
 	    }
+	    else {
+		int prio = (int) (ERTS_PSFLG_PRIO_MASK & state);
+		erts_smp_runq_unlock(rq);
 
-	end_of_proc:
+		to_rq = mp->prio[prio].runq;
+		RUNQ_SET_RQ(&proc->run_queue, to_rq);
 
-#ifdef DEBUG
-	    for (proc = evac_rq->procs.prio[prio].first;
-		 proc;
-		 proc = proc->next) {
-		ASSERT(proc->bound_runq);
+		erts_smp_runq_lock(to_rq);
+		enqueue_process(to_rq, prio, proc);
+		erts_smp_runq_unlock(to_rq);
+		notify = 1;
+
+		erts_smp_runq_lock(rq);
 	    }
-#endif
-	    break;
-	case PRIORITY_LOW:
-	    break;
-	default:
-	    ASSERT(!"Invalid process priority");
-	    break;
+	    proc = dequeue_process(rq, prio_q, &state);
 	}
+	if (notify)
+	    smp_notify_inc_runq(to_rq);
     }
 
-    if (rq_locked)
-	erts_smp_runq_unlock(rq);
-
-    if (evac_rq_locked)
-	erts_smp_runq_unlock(evac_rq);
-
-    if (notify_to_rq)
-	smp_notify_inc_runq(rq);
-
-    wake_scheduler(evac_rq, 0);
+    if (ERTS_EMPTY_RUNQ(rq))
+	empty_runq(rq);
 }
 
 static int
-try_steal_task_from_victim(ErtsRunQueue *rq, int *rq_lockedp, ErtsRunQueue *vrq)
+try_steal_task_from_victim(ErtsRunQueue *rq, int *rq_lockedp, ErtsRunQueue *vrq, Uint32 flags)
 {
-    Process *proc;
-    int vrq_locked;
+    Uint32 procs_qmask = flags & ERTS_RUNQ_FLGS_PROCS_QMASK;
+    int max_prio_bit;
+    ErtsRunPrioQueue *rpq;
 
-    if (*rq_lockedp)
-	erts_smp_xrunq_lock(rq, vrq);
-    else
-	erts_smp_runq_lock(vrq);
-    vrq_locked = 1;
+    if (*rq_lockedp) {
+	erts_smp_runq_unlock(rq);
+	*rq_lockedp = 0;
+    }
+
+    ERTS_SMP_LC_ASSERT(!erts_smp_lc_runq_is_locked(rq));
 
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(rq, *rq_lockedp);
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(vrq, vrq_locked);
+    erts_smp_runq_lock(vrq);
 
     if (rq->halt_in_progress)
-	goto try_steal_port;
+	goto no_procs;
 
     /*
      * Check for a runnable process to steal...
      */
 
-    switch (vrq->flags & ERTS_RUNQ_FLGS_PROCS_QMASK) {
-    case MAX_BIT:
-    case MAX_BIT|HIGH_BIT:
-    case MAX_BIT|NORMAL_BIT:
-    case MAX_BIT|LOW_BIT:
-    case MAX_BIT|HIGH_BIT|NORMAL_BIT:
-    case MAX_BIT|HIGH_BIT|LOW_BIT:
-    case MAX_BIT|NORMAL_BIT|LOW_BIT:
-    case MAX_BIT|HIGH_BIT|NORMAL_BIT|LOW_BIT:
-	for (proc = vrq->procs.prio[PRIORITY_MAX].last;
-	     proc;
-	     proc = proc->prev) {
-	    if (!proc->bound_runq)
-		break;
-	}
-	if (proc)
+    while (procs_qmask) {
+	Process *prev_proc;
+	Process *proc;
+
+	max_prio_bit = procs_qmask & -procs_qmask;
+	switch (max_prio_bit) {
+	case MAX_BIT:
+	    rpq = &vrq->procs.prio[PRIORITY_MAX];
 	    break;
-    case HIGH_BIT:
-    case HIGH_BIT|NORMAL_BIT:
-    case HIGH_BIT|LOW_BIT:
-    case HIGH_BIT|NORMAL_BIT|LOW_BIT:
-	for (proc = vrq->procs.prio[PRIORITY_HIGH].last;
-	     proc;
-	     proc = proc->prev) {
-	    if (!proc->bound_runq)
-		break;
-	}
-	if (proc)
+	case HIGH_BIT:
+	    rpq = &vrq->procs.prio[PRIORITY_HIGH];
 	    break;
-    case NORMAL_BIT:
-    case LOW_BIT:
-    case NORMAL_BIT|LOW_BIT:
-	for (proc = vrq->procs.prio[PRIORITY_NORMAL].last;
-	     proc;
-	     proc = proc->prev) {
-	    if (!proc->bound_runq)
-		break;
-	}
-	if (proc)
+	case NORMAL_BIT:
+	case LOW_BIT:
+	    rpq = &vrq->procs.prio[PRIORITY_NORMAL];
 	    break;
-    case 0:
-	proc = NULL;
-	break;
-    default:
-	ASSERT(!"Invalid queue mask");
-	proc = NULL;
-	break;
-    }
+	case 0:
+	    goto no_procs;
+	default:
+	    ASSERT(!"Invalid queue mask");
+	    goto no_procs;
+	}
 
-    if (proc) {
-	ErtsProcLocks proc_locks = 0;
-	int res;
-	ErtsMigrateResult mres;
-	mres = erts_proc_migrate(proc, &proc_locks,
-				 vrq, &vrq_locked,
-				 rq, rq_lockedp);
-	if (proc_locks)
-	    erts_smp_proc_unlock(proc, proc_locks);
-	res = !0;
-	switch (mres) {
-	case ERTS_MIGRATE_FAILED_RUNQ_SUSPENDED:
-	    res = 0;
-	case ERTS_MIGRATE_SUCCESS:
-	    if (vrq_locked)
+	prev_proc = NULL;
+	proc = rpq->first;
+
+	while (proc) {
+	    erts_aint32_t state = erts_smp_atomic32_read_acqb(&proc->state);
+	    if (!(ERTS_PSFLG_BOUND & state)) {
+		/* Steal process */
+		int prio = (int) (ERTS_PSFLG_PRIO_MASK & state);
+		ErtsRunQueueInfo *rqi = &vrq->procs.prio_info[prio];
+		unqueue_process(vrq, rpq, rqi, prio, prev_proc, proc);
 		erts_smp_runq_unlock(vrq);
-	    return res;
-	default: /* Other failures */
-	    break;			
-	}
-    }
+		RUNQ_SET_RQ(&proc->run_queue, rq);
 
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(rq, *rq_lockedp);
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(vrq, vrq_locked);
+		erts_smp_runq_lock(rq);
+		*rq_lockedp = 1;
+		enqueue_process(rq, prio, proc);
+		return !0;
+	    }
+	    prev_proc = proc;
+	    proc = proc->next;
+	}
 
-    if (!vrq_locked) {
-	if (*rq_lockedp)
-	    erts_smp_xrunq_lock(rq, vrq);
-	else
-	    erts_smp_runq_lock(vrq);
-	vrq_locked = 1;
+	procs_qmask &= ~max_prio_bit;
     }
 
- try_steal_port:
+no_procs:
 
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(rq, *rq_lockedp);
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(vrq, vrq_locked);
+    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(vrq));
 
     /*
      * Check for a runnable port to steal...
      */
 
-    if (vrq->ports.info.len) {
-	Port *prt = vrq->ports.end;
-	int prt_locked = 0;
-	int res;
-	ErtsMigrateResult mres;
-
-	mres = erts_port_migrate(prt, &prt_locked,
-				 vrq, &vrq_locked,
-				 rq, rq_lockedp);
-	if (prt_locked)
-	    erts_smp_port_unlock(prt);
-	res = !0;
-	switch (mres) {
-	case ERTS_MIGRATE_FAILED_RUNQ_SUSPENDED:
-	    res = 0;
-	case ERTS_MIGRATE_SUCCESS:
-	    if (vrq_locked)
-		erts_smp_runq_unlock(vrq);
-	    return res;
-	default: /* Other failures */
-	    break;			
+    if (vrq->ports.start) {
+	ErtsRunQueue *prt_rq;
+	Port *prt = erts_dequeue_port(vrq);
+	RUNQ_SET_RQ(&prt->run_queue, rq);
+	erts_smp_runq_unlock(vrq);
+
+	/*
+	 * The port might terminate while
+	 * we have no lock on it...
+	 */
+
+	prt_rq = erts_port_runq(prt);
+	if (!prt_rq)
+	    return 0;
+	else {
+	    if (prt_rq != rq)
+		erl_exit(ERTS_ABORT_EXIT,
+			 "%s:%d:%s() internal error\n",
+			 __FILE__, __LINE__, __func__);
+	    *rq_lockedp = 1;
+	    erts_enqueue_port(rq, prt);
+	    return !0;
 	}
     }
 
-    if (vrq_locked)
-	erts_smp_runq_unlock(vrq);
+    erts_smp_runq_unlock(vrq);
 
     return 0;
 }
@@ -3129,9 +3292,10 @@ static ERTS_INLINE int
 check_possible_steal_victim(ErtsRunQueue *rq, int *rq_lockedp, int vix)
 {
     ErtsRunQueue *vrq = ERTS_RUNQ_IX(vix);
-    erts_aint32_t iflgs = erts_smp_atomic32_read_nob(&vrq->info_flags);
-    if (iflgs & ERTS_RUNQ_IFLG_NONEMPTY)
-	return try_steal_task_from_victim(rq, rq_lockedp, vrq);
+    Uint32 flags = ERTS_RUNQ_FLGS_GET(vrq);
+    if ((flags & (ERTS_RUNQ_FLG_NONEMPTY
+		  | ERTS_RUNQ_FLG_PROTECTED)) == ERTS_RUNQ_FLG_NONEMPTY)
+	return try_steal_task_from_victim(rq, rq_lockedp, vrq, flags);
     else
 	return 0;
 }
@@ -3141,15 +3305,12 @@ static int
 try_steal_task(ErtsRunQueue *rq)
 {
     int res, rq_locked, vix, active_rqs, blnc_rqs;
+    Uint32 flags;
 
-    /*
-     * We are not allowed to steal jobs to this run queue
-     * if it is suspended. Note that it might get suspended
-     * at any time when we don't have the lock on the run
-     * queue.
-     */
-    if (rq->flags & ERTS_RUNQ_FLG_SUSPENDED)
-	return 0;
+    /* Protect jobs we steal from getting stolen from us... */
+    flags = ERTS_RUNQ_FLGS_SET(rq, ERTS_RUNQ_FLG_PROTECTED);
+    if (flags & ERTS_RUNQ_FLG_SUSPENDED)
+	return 0; /* go suspend instead... */
 
     res = 0;
     rq_locked = 1;
@@ -3268,12 +3429,123 @@ do {									\
     ASSERT(sum__ == (RQ)->full_reds_history_sum);			\
 } while (0);
 
+#define ERTS_PRE_ALLOCED_MPATHS 8
+
+erts_atomic_t erts_migration_paths;
+
+static struct {
+    size_t size;
+    ErtsMigrationPaths *freelist;
+    struct {
+	ErtsMigrationPaths *first;
+	ErtsMigrationPaths *last;
+    } retired;
+} mpaths;
+
+static void
+init_migration_paths(void)
+{
+    int qix, i;
+    char *p;
+    ErtsMigrationPaths *mps;
+
+    mpaths.size = sizeof(ErtsMigrationPaths);
+    mpaths.size += sizeof(ErtsMigrationPath)*(erts_no_schedulers-1);
+    mpaths.size = ERTS_ALC_CACHE_LINE_ALIGN_SIZE(mpaths.size);
+
+    p = erts_alloc_permanent_cache_aligned(ERTS_ALC_T_LL_MPATHS,
+					   (mpaths.size
+					    * ERTS_PRE_ALLOCED_MPATHS));
+    mpaths.freelist = NULL;
+    for (i = 0; i < ERTS_PRE_ALLOCED_MPATHS-1; i++) {
+	mps = (ErtsMigrationPaths *) p;
+	mps->next = mpaths.freelist;
+	mpaths.freelist = mps;
+	p += mpaths.size;
+    }
+
+    mps = (ErtsMigrationPaths *) p;
+    mps->block = NULL;
+    for (qix = 0; qix < erts_no_run_queues; qix++) {
+	int pix;
+	mps->mpath[qix].flags = 0;
+	mps->mpath[qix].misc_evac_runq = NULL;
+	for (pix = 0; pix < ERTS_NO_PRIO_LEVELS; pix++) {
+	    mps->mpath[qix].prio[pix].limit.this = -1;
+	    mps->mpath[qix].prio[pix].limit.other = -1;
+	    mps->mpath[qix].prio[pix].runq = NULL;
+	    mps->mpath[qix].prio[pix].flags = 0;
+	}
+    }
+    erts_atomic_init_wb(&erts_migration_paths, (erts_aint_t) mps);
+}
+
+static ERTS_INLINE ErtsMigrationPaths *
+alloc_mpaths(void)
+{
+    void *block;
+    ErtsMigrationPaths *res;
+    ERTS_SMP_LC_ASSERT(erts_smp_lc_mtx_is_locked(&balance_info.update_mtx));
+
+    res = mpaths.freelist;
+    if (res) {
+	mpaths.freelist = res->next;
+	res->block = NULL;
+	return res;
+    }
+    res = erts_alloc(ERTS_ALC_T_SL_MPATHS,
+		     mpaths.size+ERTS_CACHE_LINE_SIZE);
+    block = (void *) res;
+    if (((UWord) res) & ERTS_CACHE_LINE_MASK)
+	res = (ErtsMigrationPaths *) ((((UWord) res) & ~ERTS_CACHE_LINE_MASK)
+				      + ERTS_CACHE_LINE_SIZE);
+    res->block = block;
+    return res;
+}
+
+static ERTS_INLINE void
+retire_mpaths(ErtsMigrationPaths *mps)
+{
+    ErtsThrPrgrVal current;
+
+    ERTS_SMP_LC_ASSERT(erts_smp_lc_mtx_is_locked(&balance_info.update_mtx));
+
+    current = erts_thr_progress_current();
+
+    while (mpaths.retired.first) {
+	ErtsMigrationPaths *tmp = mpaths.retired.first;
+	if (!erts_thr_progress_has_reached_this(current, tmp->thr_prgr))
+	    break;
+	mpaths.retired.first = tmp->next;
+	if (tmp->block) {
+	    erts_free(ERTS_ALC_T_SL_MPATHS, tmp->block);
+	}
+	else {
+	    tmp->next = mpaths.freelist;
+	    mpaths.freelist = tmp;
+	}
+    }
+
+    if (!mpaths.retired.first)
+	mpaths.retired.last = NULL;
+
+    mps->thr_prgr = erts_thr_progress_later_than(current);
+    mps->next = NULL;
+
+    if (mpaths.retired.last)
+	mpaths.retired.last->next = mps;
+    else
+	mpaths.retired.first = mps;
+    mpaths.retired.last = mps;
+}
+
 static void
 check_balance(ErtsRunQueue *c_rq)
 {
 #if ERTS_MAX_PROCESSES >= (1 << 27)
 #  error check_balance() assumes ERTS_MAX_PROCESS < (1 << 27)
 #endif
+    ErtsMigrationPaths *new_mpaths, *old_mpaths;
     ErtsRunQueueBalance avg = {0};
     Sint64 scheds_reds, full_scheds_reds;
     int forced, active, current_active, oowc, half_full_scheds, full_scheds,
@@ -3299,9 +3571,9 @@ check_balance(ErtsRunQueue *c_rq)
 	ERTS_FOREACH_RUNQ(rq,
 	{
 	    if (rq->waiting)
-		rq->flags |= ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK;
+		ERTS_RUNQ_FLGS_SET(rq, ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK);
 	    else
-		rq->flags &= ~ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK;
+		ERTS_RUNQ_FLGS_UNSET(rq, ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK);
 	    rq->check_balance_reds = ERTS_RUNQ_CALL_CHECK_BALANCE_REDS;
 	});
 
@@ -3343,7 +3615,7 @@ check_balance(ErtsRunQueue *c_rq)
 	ErtsRunQueue *rq = ERTS_RUNQ_IX(qix);
 	erts_smp_runq_lock(rq);
 
-	run_queue_info[qix].flags = rq->flags;
+	run_queue_info[qix].flags = ERTS_RUNQ_FLGS_GET_NOB(rq);
 	for (pix = 0; pix < ERTS_NO_PROC_PRIO_LEVELS; pix++) {
 	    run_queue_info[qix].prio[pix].max_len
 		= rq->procs.prio_info[pix].max_len;
@@ -3677,47 +3949,27 @@ erts_fprintf(stderr, "--------------------------------\n");
     set_no_active_runqs(active);
 
     balance_info.halftime = 1;
-    erts_smp_atomic32_set_nob(&balance_info.checking_balance, 0);
+    new_mpaths = alloc_mpaths();
+
+    /* Write migration paths */
 
-    /* Write migration paths and reset balance statistics in all queues */
     for (qix = 0; qix < blnc_no_rqs; qix++) {
 	int mqix;
-	Uint32 flags;
-	ErtsRunQueue *rq = ERTS_RUNQ_IX(qix);
-	ErtsRunQueueInfo *rqi;
-	flags = run_queue_info[qix].flags;
-	erts_smp_runq_lock(rq);
-	flags |= (rq->flags & ~ERTS_RUNQ_FLGS_MIGRATION_INFO);
-	ASSERT(!(flags & ERTS_RUNQ_FLG_OUT_OF_WORK));
-	if (rq->waiting)
-	    flags |= ERTS_RUNQ_FLG_OUT_OF_WORK;
-
-	rq->full_reds_history_sum
-	    = run_queue_info[qix].full_reds_history_sum;
-	rq->full_reds_history[freds_hist_ix]
-	    = run_queue_info[qix].full_reds_history_change;
+	Uint32 flags = run_queue_info[qix].flags;
+	ErtsMigrationPath *mp = &new_mpaths->mpath[qix];
 
-	ERTS_DBG_CHK_FULL_REDS_HISTORY(rq);
+	mp->flags = flags;
+	mp->misc_evac_runq = NULL;
 
-	rq->out_of_work_count = 0;
-	rq->flags = flags;
-	rq->max_len = rq->len;
 	for (pix = 0; pix < ERTS_NO_PRIO_LEVELS; pix++) {
-	    rqi = (pix == ERTS_PORT_PRIO_LEVEL
-		   ? &rq->ports.info
-		   : &rq->procs.prio_info[pix]);
-	    rqi->max_len = rqi->len;
-	    rqi->reds = 0;
 	    if (!(ERTS_CHK_RUNQ_FLG_EMIGRATE(flags, pix)
 		  | ERTS_CHK_RUNQ_FLG_IMMIGRATE(flags, pix))) {
 		ASSERT(run_queue_info[qix].prio[pix].immigrate_from < 0);
 		ASSERT(run_queue_info[qix].prio[pix].emigrate_to < 0);
-#ifdef DEBUG
-		rqi->migrate.limit.this = -1;
-		rqi->migrate.limit.other = -1;
-		ERTS_DBG_SET_INVALID_RUNQP(rqi->migrate.runq, 0x2);
-#endif
-		
+		mp->prio[pix].limit.this = -1;
+		mp->prio[pix].limit.other = -1;
+		mp->prio[pix].runq = NULL;
+		mp->prio[pix].flags = 0;
 	    }
 	    else if (ERTS_CHK_RUNQ_FLG_EMIGRATE(flags, pix)) {
 		ASSERT(!ERTS_CHK_RUNQ_FLG_IMMIGRATE(flags, pix));
@@ -3725,11 +3977,12 @@ erts_fprintf(stderr, "--------------------------------\n");
 		ASSERT(run_queue_info[qix].prio[pix].emigrate_to >= 0);
 
 		mqix = run_queue_info[qix].prio[pix].emigrate_to;
-		rqi->migrate.limit.this
+		mp->prio[pix].limit.this
 		    = run_queue_info[qix].prio[pix].migration_limit;
-		rqi->migrate.limit.other
+		mp->prio[pix].limit.other
 		    = run_queue_info[mqix].prio[pix].migration_limit;
-		rqi->migrate.runq = ERTS_RUNQ_IX(mqix);
+		mp->prio[pix].runq = ERTS_RUNQ_IX(mqix);
+		mp->prio[pix].flags = run_queue_info[mqix].flags;
 	    }
 	    else {
 		ASSERT(ERTS_CHK_RUNQ_FLG_IMMIGRATE(flags, pix));
@@ -3737,24 +3990,142 @@ erts_fprintf(stderr, "--------------------------------\n");
 		ASSERT(run_queue_info[qix].prio[pix].immigrate_from >= 0);
 
 		mqix = run_queue_info[qix].prio[pix].immigrate_from;
-		rqi->migrate.limit.this
+		mp->prio[pix].limit.this
 		    = run_queue_info[qix].prio[pix].migration_limit;
-		rqi->migrate.limit.other
+		mp->prio[pix].limit.other
 		    = run_queue_info[mqix].prio[pix].migration_limit;
-		rqi->migrate.runq = ERTS_RUNQ_IX(mqix);
+		mp->prio[pix].runq = ERTS_RUNQ_IX(mqix);
+		mp->prio[pix].flags = run_queue_info[mqix].flags;
 	    }
 	}
+    }
+
+    old_mpaths = erts_get_migration_paths_managed();
+
+    /* Keep offline run-queues as is */
+    for (qix = blnc_no_rqs; qix < erts_no_schedulers; qix++) {
+	ErtsMigrationPath *nmp = &new_mpaths->mpath[qix];
+	ErtsMigrationPath *omp = &old_mpaths->mpath[qix];
+
+	nmp->flags = omp->flags;
+	nmp->misc_evac_runq = omp->misc_evac_runq;
+
+	for (pix = 0; pix < ERTS_NO_PRIO_LEVELS; pix++) {
+	    nmp->prio[pix].limit.this = omp->prio[pix].limit.this;
+	    nmp->prio[pix].limit.other = omp->prio[pix].limit.other;
+	    nmp->prio[pix].runq = omp->prio[pix].runq;
+	    nmp->prio[pix].flags = omp->prio[pix].flags;
+	}
+    }
+
+
+    /* Publish new migration paths... */
+    erts_atomic_set_wb(&erts_migration_paths, (erts_aint_t) new_mpaths);
+
+    /* Reset balance statistics in all online queues */
+    for (qix = 0; qix < blnc_no_rqs; qix++) {
+	Uint32 flags = run_queue_info[qix].flags;
+	ErtsRunQueue *rq = ERTS_RUNQ_IX(qix);
+
+	erts_smp_runq_lock(rq);
+	ASSERT(!(flags & ERTS_RUNQ_FLG_OUT_OF_WORK));
+	if (rq->waiting)
+	    flags |= ERTS_RUNQ_FLG_OUT_OF_WORK;
+
+	rq->full_reds_history_sum
+	    = run_queue_info[qix].full_reds_history_sum;
+	rq->full_reds_history[freds_hist_ix]
+	    = run_queue_info[qix].full_reds_history_change;
+
+	ERTS_DBG_CHK_FULL_REDS_HISTORY(rq);
+
+	rq->out_of_work_count = 0;
+	(void) ERTS_RUNQ_FLGS_MASK_SET(rq, ERTS_RUNQ_FLGS_MIGRATION_INFO, flags);
+
+	rq->max_len = rq->len;
+	for (pix = 0; pix < ERTS_NO_PRIO_LEVELS; pix++) {
+	    ErtsRunQueueInfo *rqi;
+	    rqi = (pix == ERTS_PORT_PRIO_LEVEL
+		   ? &rq->ports.info
+		   : &rq->procs.prio_info[pix]);
+	    erts_smp_reset_max_len(rq, rqi);
+	    rqi->reds = 0;
+	}
 
 	rq->check_balance_reds = ERTS_RUNQ_CALL_CHECK_BALANCE_REDS;
 	erts_smp_runq_unlock(rq);
     }
 
+    erts_smp_atomic32_set_nob(&balance_info.checking_balance, 0);
+
     balance_info.n++;
+    retire_mpaths(old_mpaths);
     erts_smp_mtx_unlock(&balance_info.update_mtx);
 
     erts_smp_runq_lock(c_rq);
 }
 
+static void
+change_no_used_runqs(int used)
+{
+    ErtsMigrationPaths *new_mpaths, *old_mpaths;
+    int active, qix;
+    erts_smp_mtx_lock(&balance_info.update_mtx);
+    get_no_runqs(&active, NULL);
+    set_no_used_runqs(used);
+
+    old_mpaths = erts_get_migration_paths_managed();
+    new_mpaths = alloc_mpaths();
+
+    /* Write migration paths... */
+
+    for (qix = 0; qix < used; qix++) {
+	int pix;
+	ErtsMigrationPath *omp = &old_mpaths->mpath[qix];
+	ErtsMigrationPath *nmp = &new_mpaths->mpath[qix];
+
+	nmp->flags = omp->flags & ~ERTS_RUNQ_FLGS_MIGRATION_QMASKS;
+	nmp->misc_evac_runq = NULL;
+
+	for (pix = 0; pix < ERTS_NO_PRIO_LEVELS; pix++) {
+	    nmp->prio[pix].limit.this = -1;
+	    nmp->prio[pix].limit.other = -1;
+	    nmp->prio[pix].runq = NULL;
+	    nmp->prio[pix].flags = 0;
+	}
+    }
+    for (qix = used; qix < erts_no_run_queues; qix++) {
+	int pix;
+	ErtsRunQueue *to_rq = ERTS_RUNQ_IX(qix % used);
+	ErtsMigrationPath *nmp = &new_mpaths->mpath[qix];
+
+	nmp->flags = (ERTS_RUNQ_FLGS_EMIGRATE_QMASK
+		      | ERTS_RUNQ_FLGS_EVACUATE_QMASK);
+	nmp->misc_evac_runq = to_rq;
+	for (pix = 0; pix < ERTS_NO_PRIO_LEVELS; pix++) {
+	    nmp->prio[pix].limit.this = -1;
+	    nmp->prio[pix].limit.other = -1;
+	    nmp->prio[pix].runq = to_rq;
+	    nmp->prio[pix].flags = 0;
+	}
+    }
+
+    /* ... and publish them. */
+    erts_atomic_set_wb(&erts_migration_paths, (erts_aint_t) new_mpaths);
+
+    retire_mpaths(old_mpaths);
+
+    /* Make sure that we balance soon... */
+    balance_info.forced_check_balance = 1;
+
+    erts_smp_mtx_unlock(&balance_info.update_mtx);
+
+    erts_smp_runq_lock(ERTS_RUNQ_IX(0));
+    ERTS_RUNQ_IX(0)->check_balance_reds = 0;
+    erts_smp_runq_unlock(ERTS_RUNQ_IX(0));
+}
+
+
 #endif /* #ifdef ERTS_SMP */
 
 Uint
@@ -3846,7 +4217,6 @@ erts_init_scheduling(int no_schedulers, int no_schedulers_online)
 	ErtsRunQueue *rq = ERTS_RUNQ_IX(ix);
 
 	rq->ix = ix;
-	erts_smp_atomic32_init_nob(&rq->info_flags, ERTS_RUNQ_IFLG_NONEMPTY);
 
 	/* make sure that the "extra" id correponds to the schedulers
 	 * id if the esdp->no <-> ix+1 mapping change.
@@ -3857,7 +4227,7 @@ erts_init_scheduling(int no_schedulers, int no_schedulers_online)
 
 	rq->waiting = 0;
 	rq->woken = 0;
-	rq->flags = 0;
+	ERTS_RUNQ_FLGS_INIT(rq, ERTS_RUNQ_FLG_NONEMPTY);
 	rq->check_balance_reds = ERTS_RUNQ_CALL_CHECK_BALANCE_REDS;
 	rq->full_reds_history_sum = 0;
 	for (rix = 0; rix < ERTS_FULL_REDS_HISTORY_SIZE; rix++) {
@@ -3871,19 +4241,14 @@ erts_init_scheduling(int no_schedulers, int no_schedulers_online)
 	rq->wakeup_other_reds = 0;
 	rq->halt_in_progress = 0;
 
-	rq->procs.len = 0;
 	rq->procs.pending_exiters = NULL;
 	rq->procs.context_switches = 0;
 	rq->procs.reductions = 0;
 
 	for (pix = 0; pix < ERTS_NO_PROC_PRIO_LEVELS; pix++) {
-	    rq->procs.prio_info[pix].len = 0;
+	    erts_smp_atomic32_init_nob(&rq->procs.prio_info[pix].len, 0);
 	    rq->procs.prio_info[pix].max_len = 0;
 	    rq->procs.prio_info[pix].reds = 0;
-	    rq->procs.prio_info[pix].migrate.limit.this = 0;
-	    rq->procs.prio_info[pix].migrate.limit.other = 0;
-	    ERTS_DBG_SET_INVALID_RUNQP(rq->procs.prio_info[pix].migrate.runq,
-				       0x0);
 	    if (pix < ERTS_NO_PROC_PRIO_LEVELS - 1) {
 		rq->procs.prio[pix].first = NULL;
 		rq->procs.prio[pix].last = NULL;
@@ -3892,14 +4257,10 @@ erts_init_scheduling(int no_schedulers, int no_schedulers_online)
 
 	rq->misc.start = NULL;
 	rq->misc.end = NULL;
-	rq->misc.evac_runq = NULL;
 
-	rq->ports.info.len = 0;
+	erts_smp_atomic32_init_nob(&rq->ports.info.len, 0);
 	rq->ports.info.max_len = 0;
 	rq->ports.info.reds = 0;
-	rq->ports.info.migrate.limit.this = 0;
-	rq->ports.info.migrate.limit.other = 0;
-	rq->ports.info.migrate.runq = NULL;
 	rq->ports.start = NULL;
 	rq->ports.end = NULL;
     }
@@ -4022,10 +4383,12 @@ erts_init_scheduling(int no_schedulers, int no_schedulers_online)
     balance_info.prev_rise.reds = 0;
     balance_info.n = 0;
 
+    init_migration_paths();
+
     if (no_schedulers_online < no_schedulers) {
+	change_no_used_runqs(no_schedulers_online);
 	for (ix = no_schedulers_online; ix < erts_no_run_queues; ix++)
-	    evacuate_run_queue(ERTS_RUNQ_IX(ix),
-			       ERTS_RUNQ_IX(ix % no_schedulers_online));
+	    suspend_run_queue(ERTS_RUNQ_IX(ix));
     }
 
     schdlr_sspnd.wait_curr_online = no_schedulers_online;
@@ -4088,91 +4451,208 @@ erts_get_scheduler_data(void)
 
 #endif
 
-static int remove_proc_from_runq(ErtsRunQueue *rq, Process *p, int to_inactive);
+/*
+ * scheduler_out_process() return with c_rq locked.
+ */
+static ERTS_INLINE int
+schedule_out_process(ErtsRunQueue *c_rq, erts_aint32_t state, Process *p)
+{
+    erts_aint32_t a, e, n;
+    int res = 0;
+
+    a = state;
+
+    while (1) {
+	n = e = a;
+
+	ASSERT(a & ERTS_PSFLG_RUNNING);
+	ASSERT(!(a & ERTS_PSFLG_IN_RUNQ));
+
+	n &= ~ERTS_PSFLG_RUNNING;
+	if ((a & (ERTS_PSFLG_ACTIVE|ERTS_PSFLG_SUSPENDED)) == ERTS_PSFLG_ACTIVE)
+	    n |= ERTS_PSFLG_IN_RUNQ;
+	a = erts_smp_atomic32_cmpxchg_mb(&p->state, n, e);
+	if (a == e)
+	    break;
+    }
+
+    if (!(n & ERTS_PSFLG_IN_RUNQ)) {
+	if (erts_system_profile_flags.runnable_procs)
+	    profile_runnable_proc(p, am_inactive);
+    }
+    else {
+	int prio = (int) (ERTS_PSFLG_PRIO_MASK & n);
+	ErtsRunQueue *runq = erts_get_runq_proc(p);
+
+	ASSERT(!(n & ERTS_PSFLG_SUSPENDED));
+
+#ifdef ERTS_SMP
+	if (!(ERTS_PSFLG_BOUND & n)) {
+	    ErtsRunQueue *new_runq = erts_check_emigration_need(runq, prio);
+	    if (new_runq) {
+		RUNQ_SET_RQ(&p->run_queue, new_runq);
+		runq = new_runq;
+	    }
+	}
+#endif
+	ASSERT(runq);
+	res = 1;
+
+	erts_smp_runq_lock(runq);
+
+	/* Enqueue the process */
+	enqueue_process(runq, prio, p);
+
+	if (runq == c_rq)
+	    return res;
+	erts_smp_runq_unlock(runq);
+	smp_notify_inc_runq(runq);
+    }
+    erts_smp_runq_lock(c_rq);
+    return res;
+}
 
 static ERTS_INLINE void
-suspend_process(ErtsRunQueue *rq, Process *p)
+add2runq(Process *p, erts_aint32_t state)
 {
-    ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p));
-    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(rq));
-    p->rcount++;  /* count number of suspend */
-#ifdef ERTS_SMP
-    ASSERT(!(p->runq_flags & ERTS_PROC_RUNQ_FLG_RUNNING)
-	   || p == erts_get_current_process());
-    ASSERT(p->status != P_RUNNING
-	   || p->runq_flags & ERTS_PROC_RUNQ_FLG_RUNNING);
-    if (p->status_flags & ERTS_PROC_SFLG_PENDADD2SCHEDQ)
-	goto runable;
-#endif
-    switch(p->status) {
-    case P_SUSPENDED:
-	break;
-    case P_RUNABLE:
+    int prio = (int) (ERTS_PSFLG_PRIO_MASK & state);
+    ErtsRunQueue *runq = erts_get_runq_proc(p);
+
 #ifdef ERTS_SMP
-    runable:
-        if (!ERTS_PROC_PENDING_EXIT(p)) 
+    if (!(ERTS_PSFLG_BOUND & state)) {
+	ErtsRunQueue *new_runq = erts_check_emigration_need(runq, prio);
+	if (new_runq) {
+	    RUNQ_SET_RQ(&p->run_queue, new_runq);
+	    runq = new_runq;
+	}
+    }
 #endif
-	    remove_proc_from_runq(rq, p, 1);
-	/* else:
-	 * leave process in schedq so it will discover the pending exit
-	 */
-	p->rstatus = P_RUNABLE; /* wakeup as runnable */
-	break;
-    case P_RUNNING:
-	p->rstatus = P_RUNABLE; /* wakeup as runnable */
-	break;
-    case P_WAITING:
-	p->rstatus = P_WAITING; /* wakeup as waiting */
-	break;
-    case P_EXITING:
-	return; /* ignore this */
-    case P_GARBING:
-    case P_FREE:
-	erl_exit(1, "bad state in suspend_process()\n");
+    ASSERT(runq);
+
+    erts_smp_runq_lock(runq);
+
+    /* Enqueue the process */
+    enqueue_process(runq, prio, p);
+
+    erts_smp_runq_unlock(runq);
+    smp_notify_inc_runq(runq);
+
+}
+
+static ERTS_INLINE void
+schedule_process(Process *p, erts_aint32_t state, int active_enq)
+{
+    erts_aint32_t a = state, n;
+
+    while (1) {
+	erts_aint32_t e;
+	n = e = a;
+	ASSERT(!(a & ERTS_PSFLG_FREE));
+	n |= ERTS_PSFLG_ACTIVE;
+	if (!(a & (ERTS_PSFLG_SUSPENDED|ERTS_PSFLG_RUNNING)))
+	    n |= ERTS_PSFLG_IN_RUNQ;
+	a = erts_smp_atomic32_cmpxchg_mb(&p->state, n, e);
+	if (a == e)
+	    break;
+	if (!active_enq && (a & ERTS_PSFLG_ACTIVE))
+	    return; /* Someone else activated process ... */
+    }
+
+#ifdef RRR_DEBUG
+    if (active_enq)
+	erts_fprintf(stderr, "! state=0x%x\n", n);
+#endif
+
+    if (erts_system_profile_flags.runnable_procs
+	&& !(a & (ERTS_PSFLG_ACTIVE|ERTS_PSFLG_SUSPENDED))) {
+    	profile_runnable_proc(p, am_active);
     }
 
-    if ((erts_system_profile_flags.runnable_procs) && (p->rcount == 1) && (p->status != P_WAITING)) {
-        profile_runnable_proc(p, am_inactive);
+    if ((n & ERTS_PSFLG_IN_RUNQ) && !(a & ERTS_PSFLG_IN_RUNQ)) {
+#ifdef RRR_DEBUG
+	if (active_enq)
+	    erts_fprintf(stderr, "-->\n");
+#endif
+	add2runq(p, n);
     }
+}
 
-    p->status = P_SUSPENDED;
-    
+void
+erts_schedule_process(Process *p, erts_aint32_t state)
+{
+    schedule_process(p, state, 0);
 }
 
-static ERTS_INLINE void
-resume_process(Process *p)
+static ERTS_INLINE int
+suspend_process(Process *c_p, Process *p)
 {
-    Uint32 *statusp;
+    erts_aint32_t state = erts_smp_atomic32_read_acqb(&p->state);
+    int suspended = 0;
     ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p));
-    switch (p->status) {
-    case P_SUSPENDED:
-	statusp = &p->status;
-	break;
-    case P_GARBING:
-	if (p->gcstatus == P_SUSPENDED) {
-	    statusp = &p->gcstatus;
-	    break;
+
+    if ((state & ERTS_PSFLG_SUSPENDED))
+	suspended = -1;
+    else {
+	if (c_p == p) {
+	    state = erts_smp_atomic32_read_bor_relb(&p->state,
+						    ERTS_PSFLG_SUSPENDED);
+	    state |= ERTS_PSFLG_SUSPENDED;
+	    ASSERT(state & ERTS_PSFLG_RUNNING);
+	    suspended = 1;
 	}
-	/* Fall through */
-    default:
-	return;
+	else {
+	    while (!(state & (ERTS_PSFLG_RUNNING|ERTS_PSFLG_EXITING))) {
+		erts_aint32_t e, n;
+		n = e = state;
+		n |= ERTS_PSFLG_SUSPENDED;
+		state = erts_smp_atomic32_cmpxchg_relb(&p->state, n, e);
+		if (state == e) {
+		    state = n;
+		    suspended = 1;
+		    break;
+		}
+	    }
+	}
+    }
+
+    if (state & ERTS_PSFLG_SUSPENDED) {
+
+	ASSERT(!(ERTS_PSFLG_RUNNING & state)
+	       || p == erts_get_current_process());
+
+	if (erts_system_profile_flags.runnable_procs
+	    && (p->rcount == 0)
+	    && (state & ERTS_PSFLG_ACTIVE)) {
+	    profile_runnable_proc(p, am_inactive);
+	}
+
+	p->rcount++;  /* count number of suspend */
     }
+    return suspended;
+}
+
+static ERTS_INLINE void
+resume_process(Process *p)
+{
+    erts_aint32_t state;
+    ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p));
 
     ASSERT(p->rcount > 0);
 
     if (--p->rcount > 0)  /* multiple suspend */
 	return;
-    switch(p->rstatus) {
-    case P_RUNABLE:
-	erts_add_to_runq(p);
-	break;
-    case P_WAITING:
-	*statusp = P_WAITING;
-	break;
-    default:
-	erl_exit(1, "bad state in resume_process()\n");
+
+    state = erts_smp_atomic32_read_band_mb(&p->state, ~ERTS_PSFLG_SUSPENDED);
+    state &= ~ERTS_PSFLG_SUSPENDED;
+#ifdef RRR_DEBUG
+    erts_fprintf(stderr, "%T - state=0x%x\n", p->id, state);
+#endif
+    if ((state & (ERTS_PSFLG_EXITING
+		  | ERTS_PSFLG_ACTIVE
+		  | ERTS_PSFLG_IN_RUNQ
+		  | ERTS_PSFLG_RUNNING)) == ERTS_PSFLG_ACTIVE) {
+	schedule_process(p, state, 1);
     }
-    p->rstatus = P_FREE;    
 }
 
 int
@@ -4296,6 +4776,7 @@ suspend_scheduler(ErtsSchedulerData *esdp)
     int wake = 0;
     erts_aint32_t aux_work;
     int thr_prgr_active = 1;
+    ErtsStuckBoundProcesses sbp = {NULL, NULL};
 
     /*
      * Schedulers may be suspended in two different ways:
@@ -4310,6 +4791,8 @@ suspend_scheduler(ErtsSchedulerData *esdp)
 
     ASSERT(no != 1);
 
+    evacuate_run_queue(esdp->run_queue, &sbp);
+
     erts_smp_runq_unlock(esdp->run_queue);
 
     erts_sched_check_cpu_bind_prep_suspend(esdp);
@@ -4373,17 +4856,26 @@ suspend_scheduler(ErtsSchedulerData *esdp)
 	    erts_smp_mtx_unlock(&schdlr_sspnd.mtx);
 
 	    while (1) {
+		erts_aint32_t qmask;
 		erts_aint32_t flgs;
 
+		qmask = (ERTS_RUNQ_FLGS_GET(esdp->run_queue)
+			 & ERTS_RUNQ_FLGS_QMASK);
 		aux_work = erts_atomic32_read_acqb(&ssi->aux_work);
-		if (aux_work) {
+		if (aux_work|qmask) {
 		    if (!thr_prgr_active) {
 			erts_thr_progress_active(esdp, thr_prgr_active = 1);
 			sched_wall_time_change(esdp, 1);
 		    }
-		    aux_work = handle_aux_work(&esdp->aux_work_data, aux_work);
+		    if (aux_work)
+			aux_work = handle_aux_work(&esdp->aux_work_data, aux_work);
 		    if (aux_work && erts_thr_progress_update(esdp))
 			erts_thr_progress_leader_update(esdp);
+		    if (qmask) {
+			erts_smp_runq_lock(esdp->run_queue);
+			evacuate_run_queue(esdp->run_queue, &sbp);
+			erts_smp_runq_unlock(esdp->run_queue);
+		    }
 		}
 
 		if (!aux_work) {
@@ -4453,56 +4945,11 @@ suspend_scheduler(ErtsSchedulerData *esdp)
     erts_smp_runq_lock(esdp->run_queue);
     non_empty_runq(esdp->run_queue);
 
+    schedule_bound_processes(esdp->run_queue, &sbp);
+
     erts_sched_check_cpu_bind_post_suspend(esdp);
 }
 
-#define ERTS_RUNQ_RESET_SUSPEND_INFO(RQ, DBG_ID)			\
-do {									\
-    int pix__;								\
-    (RQ)->misc.evac_runq = NULL;					\
-    (RQ)->ports.info.migrate.runq = NULL;				\
-    (RQ)->flags &= ~(ERTS_RUNQ_FLGS_IMMIGRATE_QMASK			\
-		     | ERTS_RUNQ_FLGS_EMIGRATE_QMASK			\
-		     | ERTS_RUNQ_FLGS_EVACUATE_QMASK			\
-		     | ERTS_RUNQ_FLG_SUSPENDED);			\
-    (RQ)->flags |= (ERTS_RUNQ_FLG_OUT_OF_WORK				\
-                    | ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK);		\
-    (RQ)->check_balance_reds = ERTS_RUNQ_CALL_CHECK_BALANCE_REDS;	\
-    erts_smp_atomic32_read_band_nob(&(RQ)->info_flags, ~ERTS_RUNQ_IFLG_SUSPENDED);\
-    for (pix__ = 0; pix__ < ERTS_NO_PROC_PRIO_LEVELS; pix__++) {	\
-	(RQ)->procs.prio_info[pix__].max_len = 0;			\
-	(RQ)->procs.prio_info[pix__].reds = 0;				\
-	ERTS_DBG_SET_INVALID_RUNQP((RQ)->procs.prio_info[pix__].migrate.runq,\
-				   (DBG_ID));				\
-    }									\
-    (RQ)->ports.info.max_len = 0;					\
-    (RQ)->ports.info.reds = 0;						\
-} while (0)
-
-#define ERTS_RUNQ_RESET_MIGRATION_PATHS__(RQ)				\
-do {									\
-    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked((RQ)));		\
-    (RQ)->misc.evac_runq = NULL;					\
-    (RQ)->ports.info.migrate.runq = NULL;				\
-    (RQ)->flags &= ~(ERTS_RUNQ_FLGS_IMMIGRATE_QMASK			\
-		     | ERTS_RUNQ_FLGS_EMIGRATE_QMASK			\
-		     | ERTS_RUNQ_FLGS_EVACUATE_QMASK);			\
-} while (0)
-
-#ifdef DEBUG
-#define ERTS_RUNQ_RESET_MIGRATION_PATHS(RQ, DBG_ID)			\
-do {									\
-    int pix__;								\
-    ERTS_RUNQ_RESET_MIGRATION_PATHS__((RQ));				\
-    for (pix__ = 0; pix__ < ERTS_NO_PROC_PRIO_LEVELS; pix__++)		\
-	ERTS_DBG_SET_INVALID_RUNQP((RQ)->procs.prio_info[pix__].migrate.runq,\
-				   (DBG_ID));				\
-} while (0)
-#else
-#define ERTS_RUNQ_RESET_MIGRATION_PATHS(RQ, DBG_ID) \
-  ERTS_RUNQ_RESET_MIGRATION_PATHS__((RQ))
-#endif
-
 ErtsSchedSuspendResult
 erts_schedulers_state(Uint *total,
 		      Uint *online,
@@ -4572,27 +5019,13 @@ erts_set_schedulers_online(Process *p,
 			have_unlocked_plocks = 1;
 			erts_smp_proc_unlock(p, plocks);
 		    }
-		    erts_smp_mtx_unlock(&schdlr_sspnd.mtx);
-		    erts_smp_mtx_lock(&balance_info.update_mtx);
-		    for (ix = online; ix < no; ix++) {
-			ErtsRunQueue *rq = ERTS_RUNQ_IX(ix);
-			erts_smp_runq_lock(rq);
-			ERTS_RUNQ_RESET_SUSPEND_INFO(rq, 0x5);
-			erts_smp_runq_unlock(rq);
-			scheduler_ix_resume_wake(ix);
-		    }
-		    /*
-		     * Spread evacuation paths among all online
-		     * run queues.
-		     */
-		    for (ix = no; ix < erts_no_run_queues; ix++) {
-			ErtsRunQueue *from_rq = ERTS_RUNQ_IX(ix);
-			ErtsRunQueue *to_rq = ERTS_RUNQ_IX(ix % no);
-			evacuate_run_queue(from_rq, to_rq);
-		    }
-		    set_no_used_runqs(no);
-		    erts_smp_mtx_unlock(&balance_info.update_mtx);
-		    erts_smp_mtx_lock(&schdlr_sspnd.mtx);
+		    change_no_used_runqs(no);
+
+		    for (ix = online; ix < no; ix++)
+			resume_run_queue(ERTS_RUNQ_IX(ix));
+
+		    for (ix = no; ix < erts_no_run_queues; ix++)
+			suspend_run_queue(ERTS_RUNQ_IX(ix));
 		}
 		res = ERTS_SCHDLR_SSPND_DONE;
 	    }
@@ -4619,25 +5052,11 @@ erts_set_schedulers_online(Process *p,
 			have_unlocked_plocks = 1;
 			erts_smp_proc_unlock(p, plocks);
 		    }
-		    erts_smp_mtx_unlock(&schdlr_sspnd.mtx);
-		    erts_smp_mtx_lock(&balance_info.update_mtx);
-		    
-		    for (ix = 0; ix < online; ix++) {
-			ErtsRunQueue *rq = ERTS_RUNQ_IX(ix);
-			erts_smp_runq_lock(rq);
-			ERTS_RUNQ_RESET_MIGRATION_PATHS(rq, 0x6);
-			erts_smp_runq_unlock(rq);
-		    }
-		    /*
-		     * Evacutation order important! Newly suspended run queues
-		     * has to be evacuated last.
-		     */
-		    for (ix = erts_no_run_queues-1; ix >= no; ix--)
-			evacuate_run_queue(ERTS_RUNQ_IX(ix),
-					   ERTS_RUNQ_IX(ix % no));
-		    set_no_used_runqs(no);
-		    erts_smp_mtx_unlock(&balance_info.update_mtx);
-		    erts_smp_mtx_lock(&schdlr_sspnd.mtx);
+
+		    change_no_used_runqs(no);
+		    for (ix = no; ix < erts_no_run_queues; ix++)
+			suspend_run_queue(ERTS_RUNQ_IX(ix));
+
 		    for (ix = no; ix < online; ix++) {
 			ErtsRunQueue *rq = ERTS_RUNQ_IX(ix);
 			wake_scheduler(rq, 0);
@@ -4734,25 +5153,14 @@ erts_block_multi_scheduling(Process *p, ErtsProcLocks plocks, int on, int all)
 		    schdlr_sspnd.msb.wait_active = 2;
 		}
 
-		erts_smp_mtx_unlock(&schdlr_sspnd.mtx);
-		erts_smp_mtx_lock(&balance_info.update_mtx);
-		set_no_used_runqs(1);
-		for (ix = 0; ix < online; ix++) {
+		change_no_used_runqs(1);
+		for (ix = 1; ix < erts_no_run_queues; ix++)
+		    suspend_run_queue(ERTS_RUNQ_IX(ix));
+
+		for (ix = 1; ix < online; ix++) {
 		    ErtsRunQueue *rq = ERTS_RUNQ_IX(ix);
-		    erts_smp_runq_lock(rq);
-		    ASSERT(!(rq->flags & ERTS_RUNQ_FLG_SUSPENDED));
-		    ERTS_RUNQ_RESET_MIGRATION_PATHS(rq, 0x7);
-		    erts_smp_runq_unlock(rq);
+		    wake_scheduler(rq, 0);
 		}
-		/*
-		 * Evacuate all activities in all other run queues
-		 * into the first run queue. Note order is important,
-		 * online run queues has to be evacuated last.
-		 */
-		for (ix = erts_no_run_queues-1; ix >= 1; ix--)
-		    evacuate_run_queue(ERTS_RUNQ_IX(ix), ERTS_RUNQ_IX(0));
-		erts_smp_mtx_unlock(&balance_info.update_mtx);
-		erts_smp_mtx_lock(&schdlr_sspnd.mtx);
 
 		if (erts_smp_atomic32_read_nob(&schdlr_sspnd.active)
 		    != schdlr_sspnd.msb.wait_active) {
@@ -4796,15 +5204,6 @@ erts_block_multi_scheduling(Process *p, ErtsProcLocks plocks, int on, int all)
 	    plp = proclist_create(p);
 	    plp->next = schdlr_sspnd.msb.procs;
 	    schdlr_sspnd.msb.procs = plp;
-#ifdef DEBUG
-	    ERTS_FOREACH_RUNQ(srq,
-	    {
-		if (srq != ERTS_RUNQ_IX(0)) {
-		    ASSERT(ERTS_EMPTY_RUNQ(srq));
-		    ASSERT(srq->flags & ERTS_RUNQ_FLG_SUSPENDED);
-		}
-	    });
-#endif
 	    ASSERT(p->scheduler_data);
 	}
     }
@@ -4836,27 +5235,6 @@ erts_block_multi_scheduling(Process *p, ErtsProcLocks plocks, int on, int all)
 	    res = ERTS_SCHDLR_SSPND_DONE_MSCHED_BLOCKED;
 	else {
 	    ERTS_SCHDLR_SSPND_CHNG_SET(ERTS_SCHDLR_SSPND_CHNG_MSB, 0);
-#ifdef DEBUG
-	    ERTS_FOREACH_RUNQ(rq,
-	    {
-		if (rq != p->scheduler_data->run_queue) {
-		    if (!ERTS_EMPTY_RUNQ(rq)) {
-			Process *rp;
-			int pix;
-			ASSERT(rq->ports.info.len == 0);
-			for (pix = 0; pix < ERTS_NO_PROC_PRIO_LEVELS; pix++) {
-			    for (rp = rq->procs.prio[pix].first;
-				 rp;
-				 rp = rp->next) {
-				ASSERT(rp->bound_runq);
-			    }
-			}
-		    }
-
-		    ASSERT(rq->flags & ERTS_RUNQ_FLG_SUSPENDED);
-		}
-	    });
-#endif
 	    p->flags &= ~F_HAVE_BLCKD_MSCHED;
 	    schdlr_sspnd.msb.ongoing = 0;
 	    if (schdlr_sspnd.online == 1) {
@@ -4866,35 +5244,19 @@ erts_block_multi_scheduling(Process *p, ErtsProcLocks plocks, int on, int all)
 	    }
 	    else {
 		int online = schdlr_sspnd.online;
-		erts_smp_mtx_unlock(&schdlr_sspnd.mtx);
 		if (plocks) {
 		    have_unlocked_plocks = 1;
 		    erts_smp_proc_unlock(p, plocks);
 		}
-		erts_smp_mtx_lock(&balance_info.update_mtx);
+
+		change_no_used_runqs(online);
 
 		/* Resume all online run queues */
-		for (ix = 1; ix < online; ix++) {
-		    ErtsRunQueue *rq = ERTS_RUNQ_IX(ix);
-		    erts_smp_runq_lock(rq);
-		    ERTS_RUNQ_RESET_SUSPEND_INFO(rq, 0x4);
-		    erts_smp_runq_unlock(rq);
-		    scheduler_ix_resume_wake(ix);
-		}
+		for (ix = 1; ix < online; ix++)
+		    resume_run_queue(ERTS_RUNQ_IX(ix));
 
-		/* Spread evacuation paths among all online run queues */
 		for (ix = online; ix < erts_no_run_queues; ix++)
-		    evacuate_run_queue(ERTS_RUNQ_IX(ix),
-				       ERTS_RUNQ_IX(ix % online));
-
-		set_no_used_runqs(online);
-		/* Make sure that we balance soon... */
-		balance_info.forced_check_balance = 1;
-		erts_smp_runq_lock(ERTS_RUNQ_IX(0));
-		ERTS_RUNQ_IX(0)->check_balance_reds = 0;
-		erts_smp_runq_unlock(ERTS_RUNQ_IX(0));
-		erts_smp_mtx_unlock(&balance_info.update_mtx);
-		erts_smp_mtx_lock(&schdlr_sspnd.mtx);
+		    suspend_run_queue(ERTS_RUNQ_IX(ix));
 	    }
 	    res = ERTS_SCHDLR_SSPND_DONE;
 	}
@@ -5201,10 +5563,7 @@ handle_pend_sync_suspend(Process *suspendee,
     if (suspender) {
 	ASSERT(is_nil(suspender->suspendee));
 	if (suspendee_alive) {
-	    ErtsRunQueue *rq = erts_get_runq_proc(suspendee);
-	    erts_smp_runq_lock(rq);
-	    suspend_process(rq, suspendee);
-	    erts_smp_runq_unlock(rq);
+	    erts_suspend(suspendee, suspendee_locks, NULL);
 	    suspender->suspendee = suspendee->id;
 	}
 	/* suspender is suspended waiting for suspendee to suspend;
@@ -5247,10 +5606,9 @@ pid2proc_not_running(Process *c_p, ErtsProcLocks c_p_locks,
 	    resume_process(rp);
     }
     else {
-	ErtsRunQueue *cp_rq, *rp_rq;
 
 	rp = erts_pid2proc(c_p, c_p_locks|ERTS_PROC_LOCK_STATUS,
-			   pid, ERTS_PROC_LOCK_STATUS);
+			   pid, pid_locks|ERTS_PROC_LOCK_STATUS);
 
 	if (!rp) {
 	    c_p->flags &= ~F_P2PNR_RESCHED;
@@ -5259,58 +5617,36 @@ pid2proc_not_running(Process *c_p, ErtsProcLocks c_p_locks,
 
 	ASSERT(!(c_p->flags & F_P2PNR_RESCHED));
 
-	cp_rq = erts_get_runq_proc(c_p);
-	rp_rq = erts_get_runq_proc(rp);
-	erts_smp_runqs_lock(cp_rq, rp_rq);
-	if (rp->runq_flags & ERTS_PROC_RUNQ_FLG_RUNNING) {
-	running:
-	    /* Phiu... */
-
-	    /*
-	     * If we got pending suspenders and suspend ourselves waiting
-	     * to suspend another process we might deadlock.
-	     * In this case we have to yield, be suspended by
-	     * someone else and then do it all over again.
-	     */
-	    if (!c_p->pending_suspenders) {
-		/* Mark rp pending for suspend by c_p */
-		add_pend_suspend(rp, c_p->id, handle_pend_sync_suspend);
-		ASSERT(is_nil(c_p->suspendee));
-
-		/* Suspend c_p; when rp is suspended c_p will be resumed. */
-		suspend_process(cp_rq, c_p);
-		c_p->flags |= F_P2PNR_RESCHED;
-	    }
-	    /* Yield (caller is assumed to yield immediately in bif). */
-	    erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_STATUS);
-	    rp = ERTS_PROC_LOCK_BUSY;
+	if (suspend) {
+	    if (suspend_process(c_p, rp))
+		goto done;
 	}
 	else {
-	    ErtsProcLocks need_locks = pid_locks & ~ERTS_PROC_LOCK_STATUS;
-	    if (need_locks && erts_smp_proc_trylock(rp, need_locks) == EBUSY) {
-		erts_smp_runqs_unlock(cp_rq, rp_rq);
-		erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_STATUS);
-		rp = erts_pid2proc(c_p, c_p_locks|ERTS_PROC_LOCK_STATUS,
-				   pid, pid_locks|ERTS_PROC_LOCK_STATUS);
-		if (!rp)
-		    goto done;
-		/* run-queues may have changed */
-		cp_rq = erts_get_runq_proc(c_p);
-		rp_rq = erts_get_runq_proc(rp);
-		erts_smp_runqs_lock(cp_rq, rp_rq);
-		if (rp->runq_flags & ERTS_PROC_RUNQ_FLG_RUNNING) {
-		    /* Ahh... */
-		    erts_smp_proc_unlock(rp,
-					 pid_locks & ~ERTS_PROC_LOCK_STATUS);
-		    goto running;
-		}
-	    }
+	    if (!(ERTS_PSFLG_RUNNING & erts_smp_atomic32_read_acqb(&rp->state)))
+		goto done;
 
-	    /* rp is not running and we got the locks we want... */
-	    if (suspend)
-		suspend_process(rp_rq, rp);
 	}
-	erts_smp_runqs_unlock(cp_rq, rp_rq);
+
+	/* Other process running */
+
+	/*
+	 * If we got pending suspenders and suspend ourselves waiting
+	 * to suspend another process we might deadlock.
+	 * In this case we have to yield, be suspended by
+	 * someone else and then do it all over again.
+	 */
+	if (!c_p->pending_suspenders) {
+	    /* Mark rp pending for suspend by c_p */
+	    add_pend_suspend(rp, c_p->id, handle_pend_sync_suspend);
+	    ASSERT(is_nil(c_p->suspendee));
+
+	    /* Suspend c_p; when rp is suspended c_p will be resumed. */
+	    suspend_process(c_p, c_p);
+	    c_p->flags |= F_P2PNR_RESCHED;
+	}
+	/* Yield (caller is assumed to yield immediately in bif). */
+	erts_smp_proc_unlock(rp, pid_locks|ERTS_PROC_LOCK_STATUS);
+	rp = ERTS_PROC_LOCK_BUSY;
     }
 
  done:
@@ -5367,10 +5703,10 @@ erts_pid2proc_nropt(Process *c_p, ErtsProcLocks c_p_locks,
 	return erts_pid2proc_not_running(c_p, c_p_locks, pid, pid_locks);
 }
 
-static ERTS_INLINE void
-do_bif_suspend_process(ErtsSuspendMonitor *smon,
-		       Process *suspendee,
-		       ErtsRunQueue *locked_runq)
+static ERTS_INLINE int
+do_bif_suspend_process(Process *c_p,
+		       ErtsSuspendMonitor *smon,
+		       Process *suspendee)
 {
     ASSERT(suspendee);
     ASSERT(!ERTS_PROC_IS_EXITING(suspendee));
@@ -5378,25 +5714,15 @@ do_bif_suspend_process(ErtsSuspendMonitor *smon,
 		       & erts_proc_lc_my_proc_locks(suspendee));
     if (smon) {
 	if (!smon->active) {
-	    ErtsRunQueue *rq;
-
-	    if (locked_runq)
-		rq = locked_runq;
-	    else {
-		rq = erts_get_runq_proc(suspendee);
-		erts_smp_runq_lock(rq);
-	    }
-
-	    suspend_process(rq, suspendee);
-
-	    if (!locked_runq)
-		erts_smp_runq_unlock(rq);
+	    if (!suspend_process(c_p, suspendee))
+		return 0;
 	}
 	smon->active += smon->pending;
 	ASSERT(smon->active);
 	smon->pending = 0;
+	return 1;
     }
-    
+    return 0;
 }
 
 static void
@@ -5419,10 +5745,17 @@ handle_pend_bif_sync_suspend(Process *suspendee,
 	    erts_delete_suspend_monitor(&suspender->suspend_monitors,
 					suspendee->id);
 	else {
+#ifdef DEBUG
+	    int res;
+#endif
 	    ErtsSuspendMonitor *smon;
 	    smon = erts_lookup_suspend_monitor(suspender->suspend_monitors,
 					       suspendee->id);
-	    do_bif_suspend_process(smon, suspendee, NULL);
+#ifdef DEBUG
+	    res =
+#endif
+		do_bif_suspend_process(suspendee, smon, suspendee);
+	    ASSERT(!smon || res != 0);
 	    suspender->suspendee = suspendee->id;
 	}
 	/* suspender is suspended waiting for suspendee to suspend;
@@ -5454,10 +5787,17 @@ handle_pend_bif_async_suspend(Process *suspendee,
 	    erts_delete_suspend_monitor(&suspender->suspend_monitors,
 					suspendee->id);
 	else {
+#ifdef DEBUG
+	    int res;
+#endif
 	    ErtsSuspendMonitor *smon;
 	    smon = erts_lookup_suspend_monitor(suspender->suspend_monitors,
 					       suspendee->id);
-	    do_bif_suspend_process(smon, suspendee, NULL);
+#ifdef DEBUG
+	    res =
+#endif
+	    do_bif_suspend_process(suspendee, smon, suspendee);
+	    ASSERT(!smon || res != 0);
 	}
 	erts_smp_proc_unlock(suspender, ERTS_PROC_LOCK_LINK);
     }
@@ -5542,7 +5882,8 @@ suspend_process_2(BIF_ALIST_2)
 
     /* This is really a piece of cake without SMP support... */
     if (!smon->active) {
-	suspend_process(ERTS_RUNQ_IX(0), suspendee);
+	erts_smp_atomic32_read_bor_nob(&suspendee->state, ERTS_PSFLG_SUSPENDED);
+	suspend_process(BIF_P, suspendee);
 	smon->active++;
 	res = am_true;
     }
@@ -5585,21 +5926,15 @@ suspend_process_2(BIF_ALIST_2)
 	    if (smon->pending && unless_suspending)
 		res = am_false;
 	    else {
-		ErtsRunQueue *rq;
 		if (smon->pending == INT_MAX)
 		    goto system_limit;
 
 		smon->pending++;
-		rq = erts_get_runq_proc(suspendee);
-		erts_smp_runq_lock(rq);
 
-		if (suspendee->runq_flags & ERTS_PROC_RUNQ_FLG_RUNNING)
+		if (!do_bif_suspend_process(BIF_P, smon, suspendee))
 		    add_pend_suspend(suspendee,
 				     BIF_P->id,
 				     handle_pend_bif_async_suspend);
-		else
-		    do_bif_suspend_process(smon, suspendee, rq);
-		erts_smp_runq_unlock(rq);
 
 		res = am_true;
 	    }
@@ -5636,7 +5971,6 @@ suspend_process_2(BIF_ALIST_2)
 	    /* done */
 	}
 	else {
-	    ErtsRunQueue *cp_rq, *s_rq;
 	    /* We haven't got any active suspends on the suspendee */
 
 	    /*
@@ -5653,12 +5987,7 @@ suspend_process_2(BIF_ALIST_2)
 	    if (!unless_suspending || smon->pending == 0)
 		smon->pending++;
 
-	    cp_rq = erts_get_runq_proc(BIF_P);
-	    s_rq = erts_get_runq_proc(suspendee);
-	    erts_smp_runqs_lock(cp_rq, s_rq);
-	    if (!(suspendee->runq_flags & ERTS_PROC_RUNQ_FLG_RUNNING)) {
-		do_bif_suspend_process(smon, suspendee, s_rq);
-		erts_smp_runqs_unlock(cp_rq, s_rq);
+	    if (do_bif_suspend_process(BIF_P, smon, suspendee)) {
 		res = (!unless_suspending || smon->active == 1
 		       ? am_true
 		       : am_false);
@@ -5678,8 +6007,7 @@ suspend_process_2(BIF_ALIST_2)
 		 * This time with BIF_P->suspendee == BIF_ARG_1 (see
 		 * above).
 		 */
-		suspend_process(cp_rq, BIF_P);
-		erts_smp_runqs_unlock(cp_rq, s_rq);
+		suspend_process(BIF_P, BIF_P);
 		goto yield;
 	    }
 	}
@@ -5687,9 +6015,15 @@ suspend_process_2(BIF_ALIST_2)
     }
 
 #endif /* ERTS_SMP */
-
-    ASSERT(suspendee->status == P_SUSPENDED || (asynchronous && smon->pending));
-    ASSERT(suspendee->status == P_SUSPENDED || !smon->active);
+#ifdef DEBUG
+    {
+	erts_aint32_t state = erts_smp_atomic32_read_acqb(&suspendee->state);
+	ASSERT((state & ERTS_PSFLG_SUSPENDED)
+	       || (asynchronous && smon->pending));
+	ASSERT((state & ERTS_PSFLG_SUSPENDED)
+	       || !smon->active);
+    }
+#endif
 
     erts_smp_proc_unlock(suspendee, ERTS_PROC_LOCK_STATUS);
     erts_smp_proc_unlock(BIF_P, xlocks);
@@ -5784,9 +6118,8 @@ resume_process_1(BIF_ALIST_1)
 	if (!suspendee)
 	    goto no_suspendee;
 
-	ASSERT(suspendee->status == P_SUSPENDED
-	       || (suspendee->status == P_GARBING
-		   && suspendee->gcstatus == P_SUSPENDED));
+	ASSERT(ERTS_PSFLG_SUSPENDED
+	       & erts_smp_atomic32_read_nob(&suspendee->state));
 	resume_process(suspendee);
 
 	erts_smp_proc_unlock(suspendee, ERTS_PROC_LOCK_STATUS);
@@ -5815,449 +6148,46 @@ erts_run_queues_len(Uint *qlen)
     Uint len = 0;
     ERTS_ATOMIC_FOREACH_RUNQ(rq,
     {
-	if (qlen)
-	    qlen[i++] = rq->procs.len;
-	len += rq->procs.len;
+	Sint pqlen = 0;
+	int pix;
+	for (pix = 0; pix < ERTS_NO_PROC_PRIO_LEVELS; pix++)
+	    pqlen += RUNQ_READ_LEN(&rq->procs.prio_info[pix].len);
+
+	if (pqlen < 0)
+	    pqlen = 0;
+ 	if (qlen)
+	    qlen[i++] = pqlen;
+	len += pqlen;
     }
 	);
     return len;
 }
 
-#ifdef HARDDEBUG_RUNQS
-static void
-check_procs_runq(ErtsRunQueue *runq, Process *p_in_q, Process *p_not_in_q)
-{
-    int len[ERTS_NO_PROC_PRIO_LEVELS] = {0};
-    int tot_len;
-    int prioq, prio;
-    int found_p_in_q;
-    Process *p, *prevp;
-
-    found_p_in_q = 0;
-    for (prioq = 0; prioq < ERTS_NO_PROC_PRIO_LEVELS - 1; prioq++) {
-	prevp = NULL;
-	for (p = runq->procs.prio[prioq].first; p; p = p->next) {
-	    ASSERT(p != p_not_in_q);
-	    if (p == p_in_q)
-		found_p_in_q = 1;
-	    switch (p->prio) {
-	    case PRIORITY_MAX:
-	    case PRIORITY_HIGH:
-	    case PRIORITY_NORMAL:
-		ASSERT(prioq == p->prio);
-		break;
-	    case PRIORITY_LOW:
-		ASSERT(prioq == PRIORITY_NORMAL);
-		break;
-	    default:
-		ASSERT(!"Bad prio on process");
-	    }
-	    len[p->prio]++;
-	    ASSERT(prevp == p->prev);
-	    if (p->prev) {
-		ASSERT(p->prev->next == p);
-	    }
-	    else {
-		ASSERT(runq->procs.prio[prioq].first == p);
-	    }
-	    if (p->next) {
-		ASSERT(p->next->prev == p);
-	    }
-	    else {
-		ASSERT(runq->procs.prio[prioq].last == p);
-	    }
-	    ASSERT(p->run_queue == runq);
-	    prevp = p;
-	}
-    }
-
-    ASSERT(!p_in_q || found_p_in_q);
-
-    tot_len = 0;
-    for (prio = 0; prio < ERTS_NO_PROC_PRIO_LEVELS; prio++) {
-	ASSERT(len[prio] == runq->procs.prio_info[prio].len);
-	if (len[prio]) {
-	    ASSERT(runq->flags & (1 << prio));
-	}
-	else {
-	    ASSERT(!(runq->flags & (1 << prio)));
-	}
-	tot_len += len[prio];
-    }
-    ASSERT(runq->procs.len == tot_len);    
-}
-#  define ERTS_DBG_CHK_PROCS_RUNQ(RQ) check_procs_runq((RQ), NULL, NULL)
-#  define ERTS_DBG_CHK_PROCS_RUNQ_PROC(RQ, P) check_procs_runq((RQ), (P), NULL)
-#  define ERTS_DBG_CHK_PROCS_RUNQ_NOPROC(RQ, P) check_procs_runq((RQ), NULL, (P))
-#else
-#  define ERTS_DBG_CHK_PROCS_RUNQ(RQ)
-#  define ERTS_DBG_CHK_PROCS_RUNQ_PROC(RQ, P)
-#  define ERTS_DBG_CHK_PROCS_RUNQ_NOPROC(RQ, P)
-#endif
-
-
-static ERTS_INLINE void
-enqueue_process(ErtsRunQueue *runq, Process *p)
-{
-    ErtsRunPrioQueue *rpq;
-    ErtsRunQueueInfo *rqi;
-
-    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(runq));
-    ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p));
-
-    ASSERT(p->bound_runq || !(runq->flags & ERTS_RUNQ_FLG_SUSPENDED));
-
-    rqi = &runq->procs.prio_info[p->prio];
-    rqi->len++;
-    if (rqi->max_len < rqi->len)
-	rqi->max_len = rqi->len;
-
-    runq->procs.len++;
-    runq->len++;
-    if (runq->max_len < runq->len)
-	runq->max_len = runq->len;
-
-    runq->flags |= (1 << p->prio);
-
-    rpq = (p->prio == PRIORITY_LOW
-	   ? &runq->procs.prio[PRIORITY_NORMAL]
-	   : &runq->procs.prio[p->prio]);
-
-    p->next = NULL;
-    p->prev = rpq->last;
-    if (rpq->last)
-	rpq->last->next = p;
-    else
-	rpq->first = p;
-    rpq->last = p;
-
-    switch (p->status) {
-    case P_EXITING:
-	break;
-    case P_GARBING:
-	p->gcstatus = P_RUNABLE;
-	break;
-    default:
-	p->status = P_RUNABLE;
-	break;
-    }
-
-#ifdef ERTS_SMP
-    p->status_flags |= ERTS_PROC_SFLG_INRUNQ;
-#endif
-
-    ERTS_DBG_CHK_PROCS_RUNQ_PROC(runq, p);
-}
-
-
-static ERTS_INLINE int
-dequeue_process(ErtsRunQueue *runq, Process *p)
-{
-    ErtsRunPrioQueue *rpq;
-    int res = 1;
-
-    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(runq));
-    ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p));
-
-    ERTS_DBG_CHK_PROCS_RUNQ(runq);
-
-    rpq = &runq->procs.prio[p->prio == PRIORITY_LOW ? PRIORITY_NORMAL : p->prio];
-    if (p->prev) {
-	p->prev->next = p->next;
-    }
-    else if (rpq->first == p) {
-	rpq->first = p->next;
-    }
-    else {
-	res = 0;
-    }
-    if (p->next) {
-	p->next->prev = p->prev;
-    }
-    else if (rpq->last == p) {
-	rpq->last = p->prev;
-    }
-    else {
-	ASSERT(res == 0);
-    }
-
-    if (res) {
-
-	if (--runq->procs.prio_info[p->prio].len == 0)
-	    runq->flags &= ~(1 << p->prio);
-	runq->procs.len--;
-	runq->len--;
-
-#ifdef ERTS_SMP
-	p->status_flags &= ~ERTS_PROC_SFLG_INRUNQ;
-#endif
-    }
-
-    ERTS_DBG_CHK_PROCS_RUNQ_NOPROC(runq, p);
-    return res;
-}
-
-/* schedule a process */
-static ERTS_INLINE ErtsRunQueue *
-internal_add_to_runq(ErtsRunQueue *runq, Process *p)
-{
-    Uint32 prev_status = p->status;
-    ErtsRunQueue *add_runq;
-#ifdef ERTS_SMP
-
-    ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p));
-    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(runq));
-
-    if (p->status_flags & ERTS_PROC_SFLG_INRUNQ)
-	return NULL;
-    else if (p->runq_flags & ERTS_PROC_RUNQ_FLG_RUNNING) {
-	ASSERT(ERTS_PROC_IS_EXITING(p) || p->rcount == 0);
-	ERTS_DBG_CHK_PROCS_RUNQ_NOPROC(runq, p);
-	p->status_flags |= ERTS_PROC_SFLG_PENDADD2SCHEDQ;
-	return NULL;
-    }
-    ASSERT(!p->scheduler_data);
-#endif
-
-    ERTS_DBG_CHK_PROCS_RUNQ_NOPROC(runq, p);
-#ifndef ERTS_SMP
-    /* Never schedule a suspended process (ok in smp case) */
-    ASSERT(ERTS_PROC_IS_EXITING(p) || p->rcount == 0);
-    add_runq = runq;
-#else
-    ASSERT(!p->bound_runq || p->bound_runq == p->run_queue);
-    if (p->bound_runq) {
-	if (p->bound_runq == runq)
-	    add_runq = runq;
-	else {
-	    add_runq = p->bound_runq;
-	    erts_smp_xrunq_lock(runq, add_runq);
-	}
-    }
-    else {
-	add_runq = erts_check_emigration_need(runq, p->prio);
-	if (!add_runq)
-	    add_runq = runq;
-	else /* Process emigrated */
-	    p->run_queue = add_runq;
-    }
-#endif
-
-    /* Enqueue the process */
-    enqueue_process(add_runq, p);
-
-    if ((erts_system_profile_flags.runnable_procs)
-	&& (prev_status == P_WAITING
-	    || prev_status == P_SUSPENDED)) {
-    	profile_runnable_proc(p, am_active);
-    }
-
-    if (add_runq != runq)
-	erts_smp_runq_unlock(add_runq);
-
-    return add_runq;
-}
-
-
-void
-erts_add_to_runq(Process *p)
-{
-    ErtsRunQueue *notify_runq;
-    ErtsRunQueue *runq = erts_get_runq_proc(p);
-    erts_smp_runq_lock(runq);
-    notify_runq = internal_add_to_runq(runq, p);
-    erts_smp_runq_unlock(runq);
-    smp_notify_inc_runq(notify_runq);
-
-}
-
-/* Possibly remove a scheduled process we need to suspend */
-
-static int
-remove_proc_from_runq(ErtsRunQueue *rq, Process *p, int to_inactive)
-{
-    int res;
-
-    ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p));
-
-#ifdef ERTS_SMP
-    if (p->status_flags & ERTS_PROC_SFLG_PENDADD2SCHEDQ) {
-	p->status_flags &= ~ERTS_PROC_SFLG_PENDADD2SCHEDQ;
-	ASSERT(!remove_proc_from_runq(rq, p, 0));
-	return 1;
-    }
-#endif
-
-    res = dequeue_process(rq, p);
-
-    if (res && erts_system_profile_flags.runnable_procs && to_inactive)
-	profile_runnable_proc(p, am_inactive);
-
-#ifdef ERTS_SMP
-    ASSERT(!(p->status_flags & ERTS_PROC_SFLG_INRUNQ));
-#endif
-
-    return res;
-}
-
-#ifdef ERTS_SMP
-
-ErtsMigrateResult
-erts_proc_migrate(Process *p, ErtsProcLocks *plcks,
-		  ErtsRunQueue *from_rq, int *from_locked,
-		  ErtsRunQueue *to_rq, int *to_locked)
-{
-    ERTS_SMP_LC_ASSERT(*plcks == erts_proc_lc_my_proc_locks(p));
-    ERTS_SMP_LC_ASSERT((ERTS_PROC_LOCK_STATUS & *plcks)
-		       || from_locked);
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(from_rq, *from_locked);
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(to_rq, *to_locked);
-    
-    /*
-     * If we have the lock on the run queue to migrate to,
-     * check that it isn't suspended. If it is suspended,
-     * we will refuse to migrate to it anyway.
-     */
-    if (*to_locked && (to_rq->flags & ERTS_RUNQ_FLG_SUSPENDED))
-	return ERTS_MIGRATE_FAILED_RUNQ_SUSPENDED;
-
-    /* We need status lock on process and locks on both run queues */
-
-    if (!(ERTS_PROC_LOCK_STATUS & *plcks)) {
-	if (erts_smp_proc_trylock(p, ERTS_PROC_LOCK_STATUS) == EBUSY) {
-	    ErtsProcLocks lcks = *plcks;
-	    Eterm pid = p->id;
-	    Process *proc = *plcks ? p : NULL;
-
-	    if (*from_locked) {
-		*from_locked = 0;
-		erts_smp_runq_unlock(from_rq);
-	    }
-	    if (*to_locked) {
-		*to_locked = 0;
-		erts_smp_runq_unlock(to_rq);
-	    }
-
-	    proc = erts_pid2proc_opt(proc,
-				     lcks,
-				     pid,
-				     lcks|ERTS_PROC_LOCK_STATUS,
-				     ERTS_P2P_FLG_ALLOW_OTHER_X);
-	    if (!proc) {
-		*plcks = 0;
-		return ERTS_MIGRATE_FAILED_NOT_IN_RUNQ;
-	    }
-	    ASSERT(proc == p);
-	}
-	*plcks |= ERTS_PROC_LOCK_STATUS;
-    }
-
-    ASSERT(!p->bound_runq);
-
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(from_rq, *from_locked);
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(to_rq, *to_locked);
-
-    if (p->run_queue != from_rq)
-	return ERTS_MIGRATE_FAILED_RUNQ_CHANGED;
-
-    if (!*from_locked || !*to_locked) {
-	if (from_rq < to_rq) {
-	    if (!*to_locked) {
-		if (!*from_locked)
-		    erts_smp_runq_lock(from_rq);
-		erts_smp_runq_lock(to_rq);
-	    }
-	    else if (erts_smp_runq_trylock(from_rq) == EBUSY) {
-		erts_smp_runq_unlock(to_rq);
-		erts_smp_runq_lock(from_rq);
-		erts_smp_runq_lock(to_rq);
-	    }
-	}
-	else {
-	    if (!*from_locked) {
-		if (!*to_locked)
-		    erts_smp_runq_lock(to_rq);
-		erts_smp_runq_lock(from_rq);
-	    }
-	    else if (erts_smp_runq_trylock(to_rq) == EBUSY) {
-		erts_smp_runq_unlock(from_rq);
-		erts_smp_runq_lock(to_rq);
-		erts_smp_runq_lock(from_rq);
-	    }
-	}
-	*to_locked = *from_locked = 1;
-    }
-
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(from_rq, *from_locked);
-    ERTS_SMP_LC_CHK_RUNQ_LOCK(to_rq, *to_locked);
-
-    /* Ok we now got all locks we need; do it... */
-
-    /* Refuse to migrate to a suspended run queue */
-    if (to_rq->flags & ERTS_RUNQ_FLG_SUSPENDED)
-	return ERTS_MIGRATE_FAILED_RUNQ_SUSPENDED;
-
-    if ((p->runq_flags & ERTS_PROC_RUNQ_FLG_RUNNING)
-	|| !(p->status_flags & ERTS_PROC_SFLG_INRUNQ))
-	return ERTS_MIGRATE_FAILED_NOT_IN_RUNQ;
-
-    dequeue_process(from_rq, p);
-    p->run_queue = to_rq;
-    enqueue_process(to_rq, p);
-
-    return ERTS_MIGRATE_SUCCESS;
-}
-#endif /* ERTS_SMP */
-
 Eterm
 erts_process_status(Process *c_p, ErtsProcLocks c_p_locks,
 		    Process *rp, Eterm rpid)
 {
     Eterm res = am_undefined;
-    Process *p;
-
-    if (rp) {
-	ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_STATUS
-			   & erts_proc_lc_my_proc_locks(rp));
-	p = rp;
-    }
-    else {
-	p = erts_pid2proc_opt(c_p, c_p_locks,
-			      rpid, ERTS_PROC_LOCK_STATUS,
-			      ERTS_P2P_FLG_ALLOW_OTHER_X);
-    }
+    Process *p = rp ? rp : erts_proc_lookup_raw(rpid);
 
     if (p) {
-	switch (p->status) {
-	case P_RUNABLE:
-	    res = am_runnable;
-	    break;
-	case P_WAITING:
-	    res = am_waiting;
-	    break;
-	case P_RUNNING:
-	    res = am_running;
-	    break;
-	case P_EXITING:
+	erts_aint32_t state = erts_smp_atomic32_read_acqb(&p->state);
+	if (state & ERTS_PSFLG_FREE)
+	    res = am_free;
+	else if (state & ERTS_PSFLG_EXITING)
 	    res = am_exiting;
-	    break;
-	case P_GARBING:
+	else if (state & ERTS_PSFLG_GC)
 	    res = am_garbage_collecting;
-	    break;
-	case P_SUSPENDED:
+	else if (state & ERTS_PSFLG_SUSPENDED)
 	    res = am_suspended;
-	    break;
-	case P_FREE:	/* We cannot look up a process in P_FREE... */
-	default:	/* Not a valid status... */
-	    erl_exit(1, "Bad status (%b32u) found for process %T\n",
-		     p->status, p->id);
-	    break;
-	}
-
-#ifdef ERTS_SMP
-	if (!rp && (p != c_p || !(ERTS_PROC_LOCK_STATUS & c_p_locks)))
-	    erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
+	else if (state & ERTS_PSFLG_RUNNING)
+	    res = am_running;
+	else if (state & ERTS_PSFLG_ACTIVE)
+	    res = am_runnable;
+	else
+	    res = am_waiting;
     }
+#ifdef ERTS_SMP
     else {
 	int i;
 	ErtsSchedulerData *esdp;
@@ -6272,42 +6202,40 @@ erts_process_status(Process *c_p, ErtsProcLocks c_p_locks,
 	    }
 	    erts_smp_runq_unlock(esdp->run_queue);
 	}
-
-#endif
-
     }
-
+#endif
     return res;
 }
 
 /*
-** Suspend a process 
+** Suspend a currently executing process 
 ** If we are to suspend on a port the busy_port is the thing
 ** otherwise busy_port is NIL
 */
 
 void
-erts_suspend(Process* process, ErtsProcLocks process_locks, Port *busy_port)
+erts_suspend(Process* c_p, ErtsProcLocks c_p_locks, Port *busy_port)
 {
-    ErtsRunQueue *rq;
-
-    ERTS_SMP_LC_ASSERT(process_locks == erts_proc_lc_my_proc_locks(process));
-    if (!(process_locks & ERTS_PROC_LOCK_STATUS))
-	erts_smp_proc_lock(process, ERTS_PROC_LOCK_STATUS);
-
-    rq = erts_get_runq_proc(process);
-
-    erts_smp_runq_lock(rq);
+#ifdef DEBUG
+    int res;
+#endif
+    ASSERT(c_p == erts_get_current_process());
+    ERTS_SMP_LC_ASSERT(c_p_locks == erts_proc_lc_my_proc_locks(c_p));
+    if (!(c_p_locks & ERTS_PROC_LOCK_STATUS))
+	erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_STATUS);
 
-    suspend_process(rq, process);
+#ifdef DEBUG
+    res =
+#endif
+	suspend_process(c_p, c_p);
 
-    erts_smp_runq_unlock(rq);
+    ASSERT(res);
 
     if (busy_port)
-	erts_wake_process_later(busy_port, process);
+	erts_wake_process_later(busy_port, c_p);
 
-    if (!(process_locks & ERTS_PROC_LOCK_STATUS))
-	erts_smp_proc_unlock(process, ERTS_PROC_LOCK_STATUS);
+    if (!(c_p_locks & ERTS_PROC_LOCK_STATUS))
+	erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_STATUS);
 
 }
 
@@ -6348,57 +6276,54 @@ erts_resume_processes(ErtsProcList *plp)
 Eterm
 erts_get_process_priority(Process *p)
 {
-    ErtsRunQueue *rq;
-    Eterm value;
-    ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p));
-    rq = erts_get_runq_proc(p);
-    erts_smp_runq_lock(rq);
-    switch(p->prio) {
-    case PRIORITY_MAX:		value = am_max;			break;
-    case PRIORITY_HIGH:		value = am_high;		break;
-    case PRIORITY_NORMAL:	value = am_normal;		break;
-    case PRIORITY_LOW:		value = am_low;			break;
-    default: ASSERT(0);		value = am_undefined;		break;
+    erts_aint32_t state = erts_smp_atomic32_read_nob(&p->state);
+    switch (state & ERTS_PSFLG_PRIO_MASK) {
+    case PRIORITY_MAX:		return am_max;
+    case PRIORITY_HIGH:		return am_high;
+    case PRIORITY_NORMAL:	return am_normal;
+    case PRIORITY_LOW:		return am_low;
+    default: ASSERT(0);		return am_undefined;
     }
-    erts_smp_runq_unlock(rq);
-    return value;
 }
 
 Eterm
-erts_set_process_priority(Process *p, Eterm new_value)
+erts_set_process_priority(Process *p, Eterm value)
 {
-    ErtsRunQueue *rq;
-    Eterm old_value;
-    ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p));
-    rq = erts_get_runq_proc(p);
-#ifdef ERTS_SMP
-    ASSERT(!(p->status_flags & ERTS_PROC_SFLG_INRUNQ));
-#endif
-    erts_smp_runq_lock(rq);
-    switch(p->prio) {
-    case PRIORITY_MAX:		old_value = am_max;		break;
-    case PRIORITY_HIGH:		old_value = am_high;		break;
-    case PRIORITY_NORMAL:	old_value = am_normal;		break;
-    case PRIORITY_LOW:		old_value = am_low;		break;
-    default: ASSERT(0);		old_value = am_undefined;	break;
-    }
-    switch (new_value) {
-    case am_max:		p->prio = PRIORITY_MAX;		break;
-    case am_high:		p->prio = PRIORITY_HIGH;	break;
-    case am_normal:		p->prio = PRIORITY_NORMAL;	break;
-    case am_low:		p->prio = PRIORITY_LOW;		break;
-    default:			old_value = THE_NON_VALUE;	break;
+    erts_aint32_t a, oprio, nprio;
+
+    switch (value) {
+    case am_max:	nprio = (erts_aint32_t) PRIORITY_MAX;		break;
+    case am_high:	nprio = (erts_aint32_t) PRIORITY_HIGH;		break;
+    case am_normal:	nprio = (erts_aint32_t) PRIORITY_NORMAL;	break;
+    case am_low:	nprio = (erts_aint32_t) PRIORITY_LOW;		break;
+    default:		return THE_NON_VALUE;				break;
     }
-    erts_smp_runq_unlock(rq);
-    return old_value;
-}
 
-/* note that P_RUNNING is only set so that we don't try to remove
-** running processes from the schedule queue if they exit - a running
-** process not being in the schedule queue!! 
-** Schedule for up to INPUT_REDUCTIONS context switches,
-** return 1 if more to do.
-*/
+    a = erts_smp_atomic32_read_nob(&p->state);
+    if (nprio == (a & ERTS_PSFLG_PRIO_MASK))
+	oprio = nprio;
+    else {
+	erts_aint32_t e, n;
+	do {
+	    oprio = a & ERTS_PSFLG_PRIO_MASK;
+	    n = e = a;
+
+	    ASSERT(!(a & ERTS_PSFLG_IN_RUNQ));
+
+	    n &= ~ERTS_PSFLG_PRIO_MASK;
+	    n |= nprio;
+	    a = erts_smp_atomic32_cmpxchg_mb(&p->state, n, e);
+	} while (a != e);
+    }
+
+    switch (oprio) {
+    case PRIORITY_MAX:		return am_max;
+    case PRIORITY_HIGH:		return am_high;
+    case PRIORITY_NORMAL:	return am_normal;
+    case PRIORITY_LOW:		return am_low;
+    default: ASSERT(0);		return am_undefined;
+    }
+}
 
 /*
  * schedule() is called from BEAM (process_main()) or HiPE
@@ -6421,7 +6346,6 @@ erts_set_process_priority(Process *p, Eterm new_value)
 Process *schedule(Process *p, int calls)
 {
     ErtsRunQueue *rq;
-    ErtsRunPrioQueue *rpq;
     erts_aint_t dt;
     ErtsSchedulerData *esdp;
     int context_reds;
@@ -6429,6 +6353,8 @@ Process *schedule(Process *p, int calls)
     int input_reductions;
     int actual_reds;
     int reds;
+    Uint32 flags;
+    erts_aint32_t state = 0; /* Supress warning... */
 
 #ifdef USE_VM_PROBES
     if (p != NULL && DTRACE_ENABLED(process_unscheduled)) {
@@ -6484,68 +6410,49 @@ Process *schedule(Process *p, int calls)
 
 	erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
 
-	if ((erts_system_profile_flags.runnable_procs)
-	    && (p->status == P_WAITING)) {
-	    profile_runnable_proc(p, am_inactive);
-	}
+	state = erts_smp_atomic32_read_acqb(&p->state);
 
 	if (IS_TRACED(p)) {
-	    if (IS_TRACED_FL(p, F_TRACE_CALLS) &&  p->status != P_FREE) {
+	    if (IS_TRACED_FL(p, F_TRACE_CALLS) && !(state & ERTS_PSFLG_FREE)) {
 		erts_schedule_time_break(p, ERTS_BP_CALL_TIME_SCHEDULE_OUT);
 	    }
-	    switch (p->status) {
-	    case P_EXITING:
-		if (ARE_TRACE_FLAGS_ON(p, F_TRACE_SCHED_EXIT))
-		    trace_sched(p, am_out_exiting);
-		break;
-	    case P_FREE:
+	    if (state & (ERTS_PSFLG_FREE|ERTS_PSFLG_EXITING)) {
 		if (ARE_TRACE_FLAGS_ON(p, F_TRACE_SCHED_EXIT))
-		    trace_sched(p, am_out_exited);
-		break;
-	    default:
+		    trace_sched(p, ((state & ERTS_PSFLG_FREE)
+				    ? am_out_exited
+				    : am_out_exiting));
+	    }
+	    else {
 		if (ARE_TRACE_FLAGS_ON(p, F_TRACE_SCHED))
 		    trace_sched(p, am_out);
 		else if (ARE_TRACE_FLAGS_ON(p, F_TRACE_SCHED_PROCS))
 		    trace_virtual_sched(p, am_out);
-		break;
 	    }
 	}	
 
 #ifdef ERTS_SMP
-	if (ERTS_PROC_PENDING_EXIT(p)) {
-	    erts_handle_pending_exit(p,
-				     ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_STATUS);
-	    p->status_flags |= ERTS_PROC_SFLG_PENDADD2SCHEDQ;
-	}
-
-	if (p->pending_suspenders) {
-	    handle_pending_suspend(p,
-				   ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_STATUS);
-	    ASSERT(!(p->status_flags & ERTS_PROC_SFLG_PENDADD2SCHEDQ)
-		   || p->rcount == 0);
-	}
+	if (state & ERTS_PSFLG_PENDING_EXIT)
+	    erts_handle_pending_exit(p, (ERTS_PROC_LOCK_MAIN
+					 | ERTS_PROC_LOCK_STATUS));
+	if (p->pending_suspenders) 
+	    handle_pending_suspend(p, (ERTS_PROC_LOCK_MAIN
+				       | ERTS_PROC_LOCK_STATUS));
 #endif
-	erts_smp_runq_lock(rq);
 
-	ERTS_PROC_REDUCTIONS_EXECUTED(rq, p->prio, reds, actual_reds);
+	schedule_out_process(rq, state, p); /* Returns with rq locked! */
+
+	ERTS_PROC_REDUCTIONS_EXECUTED(rq,
+				      (int) (state & ERTS_PSFLG_PRIO_MASK),
+				      reds,
+				      actual_reds);
 
 	esdp->current_process = NULL;
 #ifdef ERTS_SMP
 	p->scheduler_data = NULL;
-	p->runq_flags &= ~ERTS_PROC_RUNQ_FLG_RUNNING;
-	p->status_flags &= ~ERTS_PROC_SFLG_RUNNING;
-
-	if (p->status_flags & ERTS_PROC_SFLG_PENDADD2SCHEDQ) {
-	    ErtsRunQueue *notify_runq;
-	    p->status_flags &= ~ERTS_PROC_SFLG_PENDADD2SCHEDQ;
-	    notify_runq = internal_add_to_runq(rq, p);
-	    if (notify_runq != rq)
-		smp_notify_inc_runq(notify_runq);
-	}
 #endif
 
 
-	if (p->status == P_FREE) {
+	if (state & ERTS_PSFLG_FREE) {
 #ifdef ERTS_SMP
 	    ASSERT(esdp->free_process == p);
 	    esdp->free_process = NULL;
@@ -6576,8 +6483,9 @@ Process *schedule(Process *p, int calls)
     ERTS_SMP_LC_ASSERT(!erts_thr_progress_is_blocking());
 
  check_activities_to_run: {
-
 #ifdef ERTS_SMP
+	ErtsMigrationPaths *mps;
+	ErtsMigrationPath *mp;
 
 #ifdef ERTS_SMP
 	{
@@ -6599,20 +6507,28 @@ Process *schedule(Process *p, int calls)
 	ERTS_SMP_LC_ASSERT(!erts_thr_progress_is_blocking());
 	ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(rq));
 
-	if (rq->flags & ERTS_RUNQ_FLGS_IMMIGRATE_QMASK)
-	    immigrate(rq);
+	mps = erts_get_migration_paths_managed();
+	mp = &mps->mpath[rq->ix];
+
+	if (mp->flags & ERTS_RUNQ_FLGS_IMMIGRATE_QMASK)
+	    immigrate(rq, mp);
 
- continue_check_activities_to_run:
+    continue_check_activities_to_run:
+	flags = ERTS_RUNQ_FLGS_GET_NOB(rq);
+    continue_check_activities_to_run_known_flags:
 
-	if (rq->flags & (ERTS_RUNQ_FLG_CHK_CPU_BIND
-			 | ERTS_RUNQ_FLG_SUSPENDED)) {
-	    if (rq->flags & ERTS_RUNQ_FLG_SUSPENDED) {
-		ASSERT(erts_smp_atomic32_read_nob(&esdp->ssi->flags)
-		       & ERTS_SSI_FLG_SUSPENDED);
+
+	if (flags & (ERTS_RUNQ_FLG_CHK_CPU_BIND|ERTS_RUNQ_FLG_SUSPENDED)) {
+	
+	    if (flags & ERTS_RUNQ_FLG_SUSPENDED) {
 		suspend_scheduler(esdp);
+		flags = ERTS_RUNQ_FLGS_GET_NOB(rq);
 	    }
-	    if (rq->flags & ERTS_RUNQ_FLG_CHK_CPU_BIND)
+	    if (flags & ERTS_RUNQ_FLG_CHK_CPU_BIND) {
+		flags = ERTS_RUNQ_FLGS_UNSET(rq, ERTS_RUNQ_FLG_CHK_CPU_BIND);
+		flags &= ~ ERTS_RUNQ_FLG_CHK_CPU_BIND;
 		erts_sched_check_cpu_bind(esdp);
+	    }
 	}
 
 	{
@@ -6641,14 +6557,12 @@ Process *schedule(Process *p, int calls)
 	}
 #endif /* ERTS_SMP */
 
-	ASSERT(rq->len == rq->procs.len + rq->ports.info.len);
-
-	if ((rq->len == 0 && !rq->misc.start)
-	    || (rq->halt_in_progress
-		&& rq->ports.info.len == 0 && !rq->misc.start)) {
+	flags = ERTS_RUNQ_FLGS_GET_NOB(rq);
 
+	if ((!(flags & ERTS_RUNQ_FLGS_QMASK) && !rq->misc.start)
+	    || (rq->halt_in_progress && ERTS_EMPTY_RUNQ_PORTS(rq))) {
+	    /* Prepare for scheduler wait */
 #ifdef ERTS_SMP
-
 	    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(rq));
 
 	    rq->wakeup_other = 0;
@@ -6656,21 +6570,27 @@ Process *schedule(Process *p, int calls)
 
 	    empty_runq(rq);
 
-	    if (rq->flags & ERTS_RUNQ_FLG_SUSPENDED) {
-		ASSERT(erts_smp_atomic32_read_nob(&esdp->ssi->flags)
-		       & ERTS_SSI_FLG_SUSPENDED);
+	    flags = ERTS_RUNQ_FLGS_GET_NOB(rq);
+	    if (flags & ERTS_RUNQ_FLG_SUSPENDED) {
 		non_empty_runq(rq);
-		goto continue_check_activities_to_run;
+		goto continue_check_activities_to_run_known_flags;
 	    }
-	    else if (!(rq->flags & ERTS_RUNQ_FLG_INACTIVE)) {
+	    else if (!(flags & ERTS_RUNQ_FLG_INACTIVE)) {
+		if (try_steal_task(rq)) {
+		    non_empty_runq(rq);
+		    goto continue_check_activities_to_run;
+		}
+
+		ERTS_RUNQ_FLGS_UNSET(rq, ERTS_RUNQ_FLG_PROTECTED);
+
 		/*
 		 * Check for ERTS_RUNQ_FLG_SUSPENDED has to be done
 		 * after trying to steal a task.
 		 */
-		if (try_steal_task(rq)
-		    || (rq->flags & ERTS_RUNQ_FLG_SUSPENDED)) {
+		flags = ERTS_RUNQ_FLGS_GET_NOB(rq);
+		if (flags & ERTS_RUNQ_FLG_SUSPENDED) {
 		    non_empty_runq(rq);
-		    goto continue_check_activities_to_run;
+		    goto continue_check_activities_to_run_known_flags;
 		}
 	    }
 
@@ -6701,6 +6621,7 @@ Process *schedule(Process *p, int calls)
 	    erl_sys_schedule(1);
 	    dt = erts_do_time_read_and_reset();
 	    if (dt) erts_bump_timer(dt);
+
 #ifdef ERTS_SMP
 	    erts_smp_runq_lock(rq);
 	    clear_sys_scheduling();
@@ -6717,14 +6638,17 @@ Process *schedule(Process *p, int calls)
 	{
 	    int wo_reds = rq->wakeup_other_reds;
 	    if (wo_reds) {
-		if (rq->len < 2) {
+		erts_aint32_t len = rq->len;
+		if (len < 2) {
 		    rq->wakeup_other -= ERTS_WAKEUP_OTHER_DEC*wo_reds;
 		    if (rq->wakeup_other < 0)
 			rq->wakeup_other = 0;
 		}
 		else if (rq->wakeup_other < wakeup_other_limit)
-		    rq->wakeup_other += rq->len*wo_reds + ERTS_WAKEUP_OTHER_FIXED_INC;
+		    rq->wakeup_other += len*wo_reds + ERTS_WAKEUP_OTHER_FIXED_INC;
 		else {
+		    if (flags & ERTS_RUNQ_FLG_PROTECTED)
+			ERTS_RUNQ_FLGS_UNSET(rq, ERTS_RUNQ_FLG_PROTECTED);
 		    if (erts_smp_atomic32_read_acqb(&no_empty_run_queues) != 0) {
 			wake_scheduler_on_empty_runq(rq);
 			rq->wakeup_other = 0;
@@ -6740,7 +6664,7 @@ Process *schedule(Process *p, int calls)
 	 * Find a new port to run.
 	 */
 
-	if (rq->ports.info.len) {
+	if (RUNQ_READ_LEN(&rq->ports.info.len)) {
 	    int have_outstanding_io;
 	    have_outstanding_io = erts_port_task_execute(rq, &esdp->current_port);
 	    if ((have_outstanding_io && fcalls > 2*input_reductions)
@@ -6767,160 +6691,123 @@ Process *schedule(Process *p, int calls)
 	/*
 	 * Find a new process to run.
 	 */
- pick_next_process:
-
-    ERTS_DBG_CHK_PROCS_RUNQ(rq);
-
-      switch (rq->flags & ERTS_RUNQ_FLGS_PROCS_QMASK) {
-	case MAX_BIT:
-	case MAX_BIT|HIGH_BIT:
-	case MAX_BIT|NORMAL_BIT:
-	case MAX_BIT|LOW_BIT:
-	case MAX_BIT|HIGH_BIT|NORMAL_BIT:
-	case MAX_BIT|HIGH_BIT|LOW_BIT:
-	case MAX_BIT|NORMAL_BIT|LOW_BIT:
-	case MAX_BIT|HIGH_BIT|NORMAL_BIT|LOW_BIT:
-	    rpq = &rq->procs.prio[PRIORITY_MAX];
-	    break;
-	case HIGH_BIT:
-	case HIGH_BIT|NORMAL_BIT:
-	case HIGH_BIT|LOW_BIT:
-	case HIGH_BIT|NORMAL_BIT|LOW_BIT:
-	    rpq = &rq->procs.prio[PRIORITY_HIGH];
-	    break;
-        case NORMAL_BIT:
-	    rpq = &rq->procs.prio[PRIORITY_NORMAL];
-	    break;
-        case LOW_BIT:
-	    rpq = &rq->procs.prio[PRIORITY_NORMAL];
-	    break;
-	case NORMAL_BIT|LOW_BIT:	  
-	    rpq = &rq->procs.prio[PRIORITY_NORMAL];
-	    ASSERT(rpq->first != NULL);
-	    p = rpq->first;
-	    if (p->prio == PRIORITY_LOW) {
-		if (p == rpq->last || p->skipped >= RESCHEDULE_LOW-1)
-		    p->skipped = 0;
-		else {
-		    /* skip it */
-		    p->skipped++;
-		    rpq->first = p->next;
-		    rpq->first->prev = NULL;
-		    rpq->last->next = p;
-		    p->prev = rpq->last;
-		    p->next = NULL;
-		    rpq->last = p;
+    pick_next_process: {
+	    int prio_q;
+	    int qmask;
+
+	    flags = ERTS_RUNQ_FLGS_GET_NOB(rq);
+	    qmask = (int) (flags & ERTS_RUNQ_FLGS_PROCS_QMASK);
+	    switch (qmask & -qmask) {
+	    case MAX_BIT:
+		prio_q = PRIORITY_MAX;
+		break;
+	    case HIGH_BIT:
+		prio_q = PRIORITY_HIGH;
+		break;
+	    case NORMAL_BIT:
+	    case LOW_BIT:
+		prio_q = PRIORITY_NORMAL;
+		if (check_requeue_process(rq, PRIORITY_NORMAL))
 		    goto pick_next_process;
-		}
+		break;
+	    case 0:			/* No process at all */
+	    default:
+		ASSERT(qmask == 0);
+		goto check_activities_to_run;
 	    }
-	    break;
-        case 0:			/* No process at all */
-	default:
-	    ASSERT((rq->flags & ERTS_RUNQ_FLGS_PROCS_QMASK) == 0);
-	    ASSERT(rq->procs.len == 0);
-	    goto check_activities_to_run;
-	}
-
-        BM_START_TIMER(system);
-
-	/*
-	 * Take the chosen process out of the queue.
-	 */
-	ASSERT(rpq->first); /* Wrong qmask in rq->flags? */
-	p = rpq->first;
-#ifdef ERTS_SMP
-	ERTS_SMP_LC_ASSERT(rq == p->run_queue);
-#endif
-	rpq->first = p->next;
-	if (!rpq->first)
-	    rpq->last = NULL;
-	else
-	    rpq->first->prev = NULL;
 
-	p->next = p->prev = NULL;
+	    BM_START_TIMER(system);
 
-	if (--rq->procs.prio_info[p->prio].len == 0)
-	    rq->flags &= ~(1 << p->prio);
-	ASSERT(rq->procs.len > 0);
-	rq->procs.len--;
-	ASSERT(rq->len > 0);
-	rq->len--;
+	    /*
+	     * Take the chosen process out of the queue.
+	     */
+	    p = dequeue_process(rq, prio_q, &state);
 
-	{
-	    Uint32 ee_flgs = (ERTS_RUNQ_FLG_EVACUATE(p->prio)
-			      | ERTS_RUNQ_FLG_EMIGRATE(p->prio));
+	    ASSERT(p); /* Wrong qmask in rq->flags? */
 
-	    if ((rq->flags & (ERTS_RUNQ_FLG_SUSPENDED|ee_flgs)) == ee_flgs)
-		ERTS_UNSET_RUNQ_FLG_EVACUATE(rq->flags, p->prio);
-	}
+	    while (1) {
+		erts_aint32_t exp, new, tmp;
+		tmp = new = exp = state;
+		new &= ~ERTS_PSFLG_IN_RUNQ;
+		tmp = state & (ERTS_PSFLG_SUSPENDED|ERTS_PSFLG_PENDING_EXIT);
+		if (tmp != ERTS_PSFLG_SUSPENDED)
+		    new |= ERTS_PSFLG_RUNNING;
+		state = erts_smp_atomic32_cmpxchg_relb(&p->state, new, exp);
+		if (state == exp) {
+		    tmp = state & (ERTS_PSFLG_SUSPENDED|ERTS_PSFLG_PENDING_EXIT);
+		    if (tmp == ERTS_PSFLG_SUSPENDED)
+			goto pick_next_process;
+		    state = new;
+		    break;
+		}
+	    }
 
-	ERTS_DBG_CHK_PROCS_RUNQ_NOPROC(rq, p);
+	    rq->procs.context_switches++;
 
-	rq->procs.context_switches++;
+	    esdp->current_process = p;
 
-	esdp->current_process = p;
+	}
 
 #ifdef ERTS_SMP
-	p->runq_flags |= ERTS_PROC_RUNQ_FLG_RUNNING;
 	erts_smp_runq_unlock(rq);
 
+	if (flags & ERTS_RUNQ_FLG_PROTECTED)
+	    ERTS_RUNQ_FLGS_UNSET(rq, ERTS_RUNQ_FLG_PROTECTED);
+
 	ERTS_SMP_CHK_NO_PROC_LOCKS;
 
 	erts_smp_proc_lock(p, ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_STATUS);
 
 	if (erts_sched_stat.enabled) {
+	    int prio;
 	    UWord old = ERTS_PROC_SCHED_ID(p,
 					  (ERTS_PROC_LOCK_MAIN
 					   | ERTS_PROC_LOCK_STATUS),
 					  (UWord) esdp->no);
 	    int migrated = old && old != esdp->no;
 
+	    prio = (int) (state & ERTS_PSFLG_PRIO_MASK);
+
 	    erts_smp_spin_lock(&erts_sched_stat.lock);
-	    erts_sched_stat.prio[p->prio].total_executed++;
-	    erts_sched_stat.prio[p->prio].executed++;
+	    erts_sched_stat.prio[prio].total_executed++;
+	    erts_sched_stat.prio[prio].executed++;
 	    if (migrated) {
-		erts_sched_stat.prio[p->prio].total_migrated++;
-		erts_sched_stat.prio[p->prio].migrated++;
+		erts_sched_stat.prio[prio].total_migrated++;
+		erts_sched_stat.prio[prio].migrated++;
 	    }
 	    erts_smp_spin_unlock(&erts_sched_stat.lock);
 	}
 
-	p->status_flags |= ERTS_PROC_SFLG_RUNNING;
-	p->status_flags &= ~ERTS_PROC_SFLG_INRUNQ;
 	if (ERTS_PROC_PENDING_EXIT(p)) {
 	    erts_handle_pending_exit(p,
 				     ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_STATUS);
+	    state = erts_smp_atomic32_read_nob(&p->state);
 	}
 	ASSERT(!p->scheduler_data);
 	p->scheduler_data = esdp;
-
 #endif
-	ASSERT(p->status != P_SUSPENDED); /* Never run a suspended process */
+	/* Never run a suspended process */
+	ASSERT(!(ERTS_PSFLG_SUSPENDED & erts_smp_atomic32_read_nob(&p->state)));
 
         ACTIVATE(p);
 	reds = context_reds;
 
 	if (IS_TRACED(p)) {
-	    switch (p->status) {
-	    case P_EXITING:
+	    if (state & ERTS_PSFLG_EXITING) {
 		if (ARE_TRACE_FLAGS_ON(p, F_TRACE_SCHED_EXIT))
 		    trace_sched(p, am_in_exiting);
-		break;
-	    default:
+	    }
+	    else {
 		if (ARE_TRACE_FLAGS_ON(p, F_TRACE_SCHED))
 		    trace_sched(p, am_in);
 		else if (ARE_TRACE_FLAGS_ON(p, F_TRACE_SCHED_PROCS))
 		    trace_virtual_sched(p, am_in);
-		break;
 	    }
 	    if (IS_TRACED_FL(p, F_TRACE_CALLS)) {
 		erts_schedule_time_break(p, ERTS_BP_CALL_TIME_SCHEDULE_IN);
 	    }
 	}
 
-	if (p->status != P_EXITING)
-	    p->status = P_RUNNING;
-
 	erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
 
 #ifdef ERTS_SMP
@@ -6928,7 +6815,7 @@ Process *schedule(Process *p, int calls)
 	    erts_check_my_tracer_proc(p);
 #endif
 
-	if (!ERTS_PROC_IS_EXITING(p)
+	if (!(state & ERTS_PSFLG_EXITING)
 	    && ((FLAGS(p) & F_FORCE_GC)
 		|| (MSO(p).overhead > BIN_VHEAP_SZ(p)))) {
 	    reds -= erts_garbage_collect(p, 0, p->arg_reg, p->arity);
@@ -7020,17 +6907,19 @@ erts_schedule_misc_op(void (*func)(void *), void *arg)
     ErtsSchedulerData *esdp = erts_get_scheduler_data();
     ErtsRunQueue *rq = esdp ? esdp->run_queue : ERTS_RUNQ_IX(0);
     ErtsMiscOpList *molp = misc_op_list_alloc();
+#ifdef ERTS_SMP
+    ErtsMigrationPaths *mpaths = erts_get_migration_paths();
 
-    erts_smp_runq_lock(rq);
-
-    while (rq->misc.evac_runq) {
-	ErtsRunQueue *tmp_rq = rq->misc.evac_runq;
-	erts_smp_runq_unlock(rq);
-	rq = tmp_rq;
-	erts_smp_runq_lock(rq);
+    if (!mpaths)
+	rq = ERTS_RUNQ_IX(0);
+    else {
+	ErtsRunQueue *erq = mpaths->mpath[rq->ix].misc_evac_runq;
+	if (erq)
+	    rq = erq;
     }
+#endif
 
-    ASSERT(!(rq->flags & ERTS_RUNQ_FLG_SUSPENDED));
+    erts_smp_runq_lock(rq);
 
     molp->next = NULL;
     molp->func = func;
@@ -7040,7 +6929,9 @@ erts_schedule_misc_op(void (*func)(void *), void *arg)
     else
 	rq->misc.start = molp;
     rq->misc.end = molp;
+
     erts_smp_runq_unlock(rq);
+
     smp_notify_inc_runq(rq);
 }
 
@@ -7201,7 +7092,7 @@ erts_free_proc(Process *p)
 ** Allocate process and find out where to place next process.
 */
 static Process*
-alloc_process(void)
+alloc_process(ErtsRunQueue *rq, erts_aint32_t state)
 {
     int pix;
     Process* p;
@@ -7280,6 +7171,12 @@ alloc_process(void)
 	exp_lpd = act_lpd;
     }
 
+#ifdef ERTS_SMP
+    RUNQ_SET_RQ(&p->run_queue, rq);
+#endif
+
+    erts_smp_atomic32_init_relb(&p->state, state);
+
 #ifdef DEBUG
     pid = p->id;
 #endif
@@ -7303,7 +7200,6 @@ alloc_process(void)
 
     erts_smp_rwmtx_runlock(&erts_proc_tab_rwmtx);
 
-    p->rstatus = P_FREE;
     p->rcount = 0;
 
     ASSERT(p == (Process *)
@@ -7317,6 +7213,7 @@ system_limit:
 
     erts_smp_rwmtx_runlock(&erts_proc_tab_rwmtx);
     return NULL;
+
 }
 
 Eterm
@@ -7326,7 +7223,7 @@ erl_create_process(Process* parent, /* Parent of process (default group leader).
 		   Eterm args,	/* Arguments for function (must be well-formed list). */
 		   ErlSpawnOpts* so) /* Options for spawn. */
 {
-    ErtsRunQueue *rq, *notify_runq;
+    ErtsRunQueue *rq = NULL;
     Process *p;
     Sint arity;			/* Number of arguments. */
 #ifndef HYBRID
@@ -7335,6 +7232,8 @@ erl_create_process(Process* parent, /* Parent of process (default group leader).
     Uint sz;			/* Needed words on heap. */
     Uint heap_need;		/* Size needed on heap. */
     Eterm res = THE_NON_VALUE;
+    erts_aint32_t state = 0;
+    erts_aint32_t prio = (erts_aint32_t) PRIORITY_NORMAL;
 
 #ifdef ERTS_SMP
     erts_smp_proc_lock(parent, ERTS_PROC_LOCKS_ALL_MINOR);
@@ -7359,8 +7258,24 @@ erl_create_process(Process* parent, /* Parent of process (default group leader).
 	so->error_code = BADARG;
 	goto error;
     }
-    p = alloc_process(); /* All proc locks are locked by this thread
-			    on success */
+
+    if (so->flags & SPO_USE_ARGS) {
+	if (so->scheduler) {
+	    int ix = so->scheduler-1;
+	    ASSERT(0 <= ix && ix < erts_no_run_queues);
+	    rq = ERTS_RUNQ_IX(ix);
+	    state |= ERTS_PSFLG_BOUND;
+	}
+	prio = (erts_aint32_t) so->priority;
+    }
+
+    state |= (prio & ERTS_PSFLG_PRIO_MASK);
+
+    if (!rq)
+	rq = erts_get_runq_proc(parent);
+
+    p = alloc_process(rq, state); /* All proc locks are locked by this thread
+				     on success */
     if (!p) {
 	erts_send_error_to_logger_str(parent->group_leader,
 				      "Too many processes\n");
@@ -7382,22 +7297,16 @@ erl_create_process(Process* parent, /* Parent of process (default group leader).
 
     p->flags = erts_default_process_flags;
 
-    /* Scheduler queue mutex should be locked when changeing
-     * prio. In this case we don't have to lock it, since
-     * noone except us has access to the process.
-     */
     if (so->flags & SPO_USE_ARGS) {
 	p->min_heap_size  = so->min_heap_size;
 	p->min_vheap_size = so->min_vheap_size;
-	p->prio           = so->priority;
 	p->max_gen_gcs    = so->max_gen_gcs;
     } else {
 	p->min_heap_size  = H_MIN_SIZE;
 	p->min_vheap_size = BIN_VH_MIN_SIZE;
-	p->prio           = PRIORITY_NORMAL;
 	p->max_gen_gcs    = (Uint16) erts_smp_atomic32_read_nob(&erts_max_gen_gcs);
     }
-    p->skipped = 0;
+    p->schedule_count = 0;
     ASSERT(p->min_heap_size == erts_next_heap_size(p->min_heap_size, 0));
     
     p->initial[INITIAL_MOD] = mod;
@@ -7501,12 +7410,7 @@ erl_create_process(Process* parent, /* Parent of process (default group leader).
 	    : STORE_NC(&p->htop, &p->off_heap, parent->group_leader);
     }
 
-#if 1
-    p->trace_flags = ~TRACEE_FLAGS;
-    p->tracer_proc = NIL;
-#else
     erts_get_default_tracing(&p->trace_flags, &p->tracer_proc);
-#endif
 
     p->msg.first = NULL;
     p->msg.last = &p->msg.first;
@@ -7516,7 +7420,6 @@ erl_create_process(Process* parent, /* Parent of process (default group leader).
     p->msg_inq.first = NULL;
     p->msg_inq.last = &p->msg_inq.first;
     p->msg_inq.len = 0;
-    p->bound_runq = NULL;
 #endif
     p->bif_timers = NULL;
     p->mbuf = NULL;
@@ -7618,9 +7521,6 @@ erl_create_process(Process* parent, /* Parent of process (default group leader).
 
 #ifdef ERTS_SMP
     p->scheduler_data = NULL;
-    erts_atomic32_init_nob(&p->aflags, 0);
-    p->status_flags = 0;
-    p->runq_flags = 0;
     p->suspendee = NIL;
     p->pending_suspenders = NULL;
     p->pending_exit.reason = THE_NON_VALUE;
@@ -7631,34 +7531,15 @@ erl_create_process(Process* parent, /* Parent of process (default group leader).
     p->fp_exception = 0;
 #endif
 
+    erts_smp_proc_unlock(p, ERTS_PROC_LOCKS_ALL);
+
+    res = p->id;
+
     /*
      * Schedule process for execution.
      */
 
-    if (!((so->flags & SPO_USE_ARGS) && so->scheduler))
-	rq = erts_get_runq_proc(parent);
-    else {
-	int ix = so->scheduler-1;
-	ASSERT(0 <= ix && ix < erts_no_run_queues);
-	rq = ERTS_RUNQ_IX(ix);
-	p->bound_runq = rq;
-    }
-
-    erts_smp_runq_lock(rq);
-
-#ifdef ERTS_SMP
-    p->run_queue = rq;
-#endif
-
-    p->status = P_WAITING;
-    notify_runq = internal_add_to_runq(rq, p);
-
-    erts_smp_runq_unlock(rq);
-
-    smp_notify_inc_runq(notify_runq);
-
-    res = p->id;
-    erts_smp_proc_unlock(p, ERTS_PROC_LOCKS_ALL);
+    schedule_process(p, state, 0);
 
     VERBOSE(DEBUG_PROCESSES, ("Created a new process: %T\n",p->id));
 
@@ -7694,12 +7575,8 @@ void erts_init_empty_process(Process *p)
     p->max_gen_gcs = 0;
     p->min_heap_size = 0;
     p->min_vheap_size = 0;
-    p->status = P_RUNABLE;
-    p->gcstatus = P_RUNABLE;
-    p->rstatus = P_RUNABLE;
     p->rcount = 0;
     p->id = ERTS_INVALID_PID;
-    p->prio = PRIORITY_NORMAL;
     p->reds = 0;
     p->tracer_proc = NIL;
     p->trace_flags = F_INITIAL_TRACE_FLAGS;
@@ -7716,7 +7593,6 @@ void erts_init_empty_process(Process *p)
     p->bin_vheap_mature = 0;
 #ifdef ERTS_SMP
     p->u.ptimer = NULL;
-    p->bound_runq = NULL;
 #else
     memset(&(p->u.tm), 0, sizeof(ErlTimer));
 #endif
@@ -7793,12 +7669,10 @@ void erts_init_empty_process(Process *p)
     p->last_old_htop = NULL;
 #endif
 
+    erts_smp_atomic32_init_nob(&p->state, (erts_aint32_t) PRIORITY_NORMAL);
 
 #ifdef ERTS_SMP
     p->scheduler_data = NULL;
-    erts_atomic32_init_nob(&p->aflags, 0);
-    p->status_flags = 0;
-    p->runq_flags = 0;
     p->msg_inq.first = NULL;
     p->msg_inq.last = &p->msg_inq.first;
     p->msg_inq.len = 0;
@@ -7808,7 +7682,7 @@ void erts_init_empty_process(Process *p)
     p->pending_exit.bp = NULL;
     erts_proc_lock_init(p);
     erts_smp_proc_unlock(p, ERTS_PROC_LOCKS_ALL);
-    p->run_queue = ERTS_RUNQ_IX(0);
+    RUNQ_SET_RQ(&p->run_queue, ERTS_RUNQ_IX(0));
 #endif
 
 #if !defined(NO_FPE_SIGNALS) || defined(HIPE)
@@ -8003,26 +7877,34 @@ delete_process(Process* p)
 
 }
 
+static ERTS_INLINE erts_aint32_t
+set_proc_exiting_state(Process *p, erts_aint32_t state)
+{
+    erts_aint32_t a, n, e;
+    a = state;
+    while (1) {
+	n = e = a;
+	n &= ~(ERTS_PSFLG_SUSPENDED|ERTS_PSFLG_PENDING_EXIT);
+	n |= ERTS_PSFLG_EXITING|ERTS_PSFLG_ACTIVE;
+	if (!(a & (ERTS_PSFLG_IN_RUNQ|ERTS_PSFLG_RUNNING)))
+	    n |= ERTS_PSFLG_IN_RUNQ;
+	a = erts_smp_atomic32_cmpxchg_relb(&p->state, n, e);
+	if (a == e)
+	    break;
+    }
+    return a;
+}
+
 static ERTS_INLINE void
-set_proc_exiting(Process *p, Eterm reason, ErlHeapFragment *bp)
+set_proc_exiting(Process *p,
+		 erts_aint32_t state,
+		 Eterm reason,
+		 ErlHeapFragment *bp)
 {
-#ifdef ERTS_SMP
-    erts_pix_lock_t *pix_lock = ERTS_PID2PIXLOCK(p->id);
     ERTS_SMP_LC_ASSERT(erts_proc_lc_my_proc_locks(p) == ERTS_PROC_LOCKS_ALL);
-    /*
-     * You are required to have all proc locks and the pix lock when going
-     * to status P_EXITING. This makes it is enough to take any lock when
-     * looking up a process (pid2proc()) to prevent the looked up process
-     * from exiting until the lock has been released.
-     */
 
-    erts_pix_lock(pix_lock);
-    erts_atomic32_read_bor_relb(&p->aflags, ERTS_PROC_AFLG_EXITING);
-#endif
-    p->status = P_EXITING;
-#ifdef ERTS_SMP
-    erts_pix_unlock(pix_lock);
-#endif
+    state = set_proc_exiting_state(p, state);
+
     p->fvalue = reason;
     if (bp)
 	erts_link_mbuf_to_proc(p, bp);
@@ -8035,6 +7917,14 @@ set_proc_exiting(Process *p, Eterm reason, ErlHeapFragment *bp)
     KILL_CATCHES(p);
     cancel_timer(p);
     p->i = (BeamInstr *) beam_exit;
+
+    if (erts_system_profile_flags.runnable_procs
+	&& !(state & (ERTS_PSFLG_ACTIVE|ERTS_PSFLG_SUSPENDED))) {
+    	profile_runnable_proc(p, am_active);
+    }
+
+    if (!(state & (ERTS_PSFLG_IN_RUNQ|ERTS_PSFLG_RUNNING)))
+	add2runq(p, state);
 }
 
 
@@ -8047,8 +7937,8 @@ erts_handle_pending_exit(Process *c_p, ErtsProcLocks locks)
     ASSERT(is_value(c_p->pending_exit.reason));
     ERTS_SMP_LC_ASSERT(erts_proc_lc_my_proc_locks(c_p) == locks);
     ERTS_SMP_LC_ASSERT(locks & ERTS_PROC_LOCK_MAIN);
-    ERTS_SMP_LC_ASSERT(c_p->status != P_EXITING);
-    ERTS_SMP_LC_ASSERT(c_p->status != P_FREE);
+    ERTS_SMP_LC_ASSERT(!((ERTS_PSFLG_EXITING|ERTS_PSFLG_FREE)
+			 & erts_smp_atomic32_read_nob(&c_p->state)));
 
     /* Ensure that all locks on c_p are locked before proceeding... */
     if (locks == ERTS_PROC_LOCKS_ALL)
@@ -8061,7 +7951,10 @@ erts_handle_pending_exit(Process *c_p, ErtsProcLocks locks)
 	}
     }
 
-    set_proc_exiting(c_p, c_p->pending_exit.reason, c_p->pending_exit.bp);
+    set_proc_exiting(c_p,
+		     erts_smp_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;
 
@@ -8077,11 +7970,12 @@ handle_pending_exiters(ErtsProcList *pnd_xtrs)
     while (plp) {
 	Process *p = erts_pid2proc(NULL, 0, plp->pid, ERTS_PROC_LOCKS_ALL);
 	if (p) {
-	    if (proclist_same(plp, p)
-		&& !(p->status_flags & ERTS_PROC_SFLG_RUNNING)) {
-		ASSERT(p->status_flags & ERTS_PROC_SFLG_INRUNQ);
-		ASSERT(ERTS_PROC_PENDING_EXIT(p));
-		erts_handle_pending_exit(p, ERTS_PROC_LOCKS_ALL);
+	    if (proclist_same(plp, p)) {
+		erts_aint32_t state = erts_smp_atomic32_read_acqb(&p->state);
+		if (!(state & ERTS_PSFLG_RUNNING)) {
+		    ASSERT(state & ERTS_PSFLG_PENDING_EXIT);
+		    erts_handle_pending_exit(p, ERTS_PROC_LOCKS_ALL);
+		}
 	    }
 	    erts_smp_proc_unlock(p, ERTS_PROC_LOCKS_ALL);
 	}
@@ -8171,7 +8065,7 @@ send_exit_message(Process *to, ErtsProcLocks *to_locksp,
  * 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 (status P_EXITING). When a process has gone into the
+ * 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
@@ -8244,6 +8138,7 @@ send_exit_signal(Process *c_p,		/* current process if and only
 		 Uint32 flags		/* flags */
     )		
 {
+    erts_aint32_t state = erts_smp_atomic32_read_nob(&rp->state);
     Eterm rsn = reason == am_kill ? am_killed : reason;
 
     ERTS_SMP_LC_ASSERT(*rp_locks == erts_proc_lc_my_proc_locks(rp));
@@ -8265,7 +8160,7 @@ send_exit_signal(Process *c_p,		/* current process if and only
     }
 #endif
 
-    if (ERTS_PROC_IS_TRAPPING_EXITS(rp)
+    if ((state & ERTS_PSFLG_TRAP_EXIT)
 	&& (reason != am_kill || (flags & ERTS_XSIG_FLG_IGN_KILL))) {
 	if (is_not_nil(token) 
 #ifdef USE_VM_PROBES
@@ -8281,9 +8176,7 @@ send_exit_signal(Process *c_p,		/* current process if and only
     }
     else if (reason != am_normal || (flags & ERTS_XSIG_FLG_NO_IGN_NORMAL)) {
 #ifdef ERTS_SMP
-	if (!ERTS_PROC_PENDING_EXIT(rp) && !ERTS_PROC_IS_EXITING(rp)) {
-	    ASSERT(rp->status != P_EXITING);
-	    ASSERT(rp->status != P_FREE);
+	if (!(state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_PENDING_EXIT))) {
 	    ASSERT(!rp->pending_exit.bp);
 
 	    if (rp == c_p && (*rp_locks & ERTS_PROC_LOCK_MAIN)) {
@@ -8299,9 +8192,9 @@ send_exit_signal(Process *c_p,		/* current process if and only
 		    }
 		    *rp_locks = ERTS_PROC_LOCKS_ALL;
 		}
-		set_proc_exiting(c_p, rsn, NULL);
+		set_proc_exiting(c_p, state, rsn, NULL);
 	    }
-	    else if (!(rp->status_flags & ERTS_PROC_SFLG_RUNNING)) {
+	    else if (!(state & ERTS_PSFLG_RUNNING)) {
 		/* Process not running ... */
 		ErtsProcLocks need_locks = ~(*rp_locks) & ERTS_PROC_LOCKS_ALL;
 		if (need_locks
@@ -8318,6 +8211,7 @@ send_exit_signal(Process *c_p,		/* current process if and only
 		    /* ...and we have all locks on it... */
 		    *rp_locks = ERTS_PROC_LOCKS_ALL;
 		    set_proc_exiting(rp,
+				     state,
 				     (is_immed(rsn)
 				      ? rsn
 				      : copy_object(rsn, rp)),
@@ -8347,13 +8241,9 @@ send_exit_signal(Process *c_p,		/* current process if and only
 							  &bp->off_heap);
 		    rp->pending_exit.bp = bp;
 		}
-		erts_atomic32_read_bor_relb(&rp->aflags,
-					    ERTS_PROC_AFLG_PENDING_EXIT);
-		ASSERT(ERTS_PROC_PENDING_EXIT(rp));
+		erts_smp_atomic32_read_bor_relb(&rp->state,
+						ERTS_PSFLG_PENDING_EXIT);
 	    }
-	    if (!(rp->status_flags
-		  & (ERTS_PROC_SFLG_INRUNQ|ERTS_PROC_SFLG_RUNNING)))
-		erts_add_to_runq(rp);
 	}
 	/* else:
 	 *
@@ -8365,18 +8255,15 @@ send_exit_signal(Process *c_p,		/* current process if and only
 	 *          exit or by itself before seeing the pending exit.
 	 */
 #else /* !ERTS_SMP */
-	if (c_p == rp) {
-	    rp->status = P_EXITING;
-	    c_p->fvalue = rsn;
-	}
-	else if (rp->status != P_EXITING) { /* No recursive process exits /PaN */
-	    Eterm old_status = rp->status;
+	erts_aint32_t state = erts_smp_atomic32_read_nob(&rp->state);
+	if (!(state & ERTS_PSFLG_EXITING)) {
 	    set_proc_exiting(rp,
-			     is_immed(rsn) ? rsn : copy_object(rsn, rp),
+			     state,
+			     (is_immed(rsn) || c_p == rp
+			      ? rsn
+			      : copy_object(rsn, rp)),
 			     NULL);
 	    ACTIVATE(rp);
-	    if (old_status != P_RUNABLE && old_status != P_RUNNING)
-		erts_add_to_runq(rp);
 	}
 #endif
 	return -1; /* Receiver will exit */
@@ -8688,22 +8575,14 @@ proc_dec_refc(void *vproc)
 #endif
 
 
-static void
-continue_exit_process(Process *p
-#ifdef ERTS_SMP
-		      , erts_pix_lock_t *pix_lock
-#endif
-    );
-
 /* this function fishishes a process and propagates exit messages - called
    by process_main when a process dies */
 void 
 erts_do_exit_process(Process* p, Eterm reason)
 {
 #ifdef ERTS_SMP
-    erts_pix_lock_t *pix_lock = ERTS_PID2PIXLOCK(p->id);
+    erts_aint32_t state;
 #endif
-
     p->arity = 0;		/* No live registers */
     p->fvalue = reason;
 
@@ -8721,27 +8600,17 @@ erts_do_exit_process(Process* p, Eterm reason)
 #ifdef ERTS_SMP
     ERTS_SMP_CHK_HAVE_ONLY_MAIN_PROC_LOCK(p);
     /* By locking all locks (main lock is already locked) when going
-       to status P_EXITING, it is enough to take any lock when
+       to exiting state (ERTS_PSFLG_EXITING), it is enough to take any lock when
        looking up a process (erts_pid2proc()) to prevent the looked up
        process from exiting until the lock has been released. */
     erts_smp_proc_lock(p, ERTS_PROC_LOCKS_ALL_MINOR);
 #endif
-    
-    if (erts_system_profile_flags.runnable_procs && (p->status != P_WAITING)) {
-    	profile_runnable_proc(p, am_inactive);
-    }
-
-#ifdef ERTS_SMP
-    erts_pix_lock(pix_lock);
-    erts_atomic32_read_bor_relb(&p->aflags, ERTS_PROC_AFLG_EXITING);
-#endif
-    
-    p->status = P_EXITING;
 
-#ifdef ERTS_SMP
-    erts_pix_unlock(pix_lock);
-
-    if (ERTS_PROC_PENDING_EXIT(p)) {
+#ifndef ERTS_SMP
+    set_proc_exiting_state(p, erts_smp_atomic32_read_nob(&p->state));
+#else
+    state = set_proc_exiting_state(p, erts_smp_atomic32_read_nob(&p->state));
+    if (state & ERTS_PSFLG_PENDING_EXIT) {
 	/* Process exited before pending exit was received... */
 	p->pending_exit.reason = THE_NON_VALUE;
 	if (p->pending_exit.bp) {
@@ -8780,29 +8649,11 @@ erts_do_exit_process(Process* p, Eterm reason)
 
     erts_smp_proc_unlock(p, ERTS_PROC_LOCKS_ALL_MINOR);
 
-#ifdef ERTS_SMP
-    continue_exit_process(p, pix_lock);
-#else
-    continue_exit_process(p);
-#endif
+    erts_continue_exit_process(p);
 }
 
 void
-erts_continue_exit_process(Process *c_p)
-{
-#ifdef ERTS_SMP
-    continue_exit_process(c_p, ERTS_PID2PIXLOCK(c_p->id));
-#else
-    continue_exit_process(c_p);
-#endif
-}
-
-static void
-continue_exit_process(Process *p
-#ifdef ERTS_SMP
-		      , erts_pix_lock_t *pix_lock
-#endif
-    )
+erts_continue_exit_process(Process *p)
 {
     ErtsLink* lnk;
     ErtsMonitor *mon;
@@ -8818,11 +8669,7 @@ continue_exit_process(Process *p
 
     ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_MAIN == erts_proc_lc_my_proc_locks(p));
 
-#ifdef DEBUG
-    erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
-    ASSERT(p->status == P_EXITING);
-    erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
-#endif
+    ASSERT(ERTS_PROC_IS_EXITING(p));
 
 #ifdef ERTS_SMP
     if (p->flags & F_HAVE_BLCKD_MSCHED) {
@@ -8914,7 +8761,6 @@ continue_exit_process(Process *p
 
 	p->scheduler_data->current_process = NULL;
 	p->scheduler_data->free_process = p;
-	p->status_flags = 0;
 #endif
 	/* Time of death! */
 	erts_smp_atomic_set_relb(&erts_proc.tab[pix], ERTS_AINT_NULL);
@@ -8946,7 +8792,21 @@ continue_exit_process(Process *p
 
     lnk = p->nlinks;
     p->nlinks = NULL;
-    p->status = P_FREE;
+
+    {
+	/* Inactivate and notify free */
+	erts_aint32_t n, e, a = erts_smp_atomic32_read_nob(&p->state);
+	while (1) {
+	    n = e = a;
+	    ASSERT(a & ERTS_PSFLG_EXITING);
+	    n |= ERTS_PSFLG_FREE;
+	    n &= ~ERTS_PSFLG_ACTIVE;
+	    a = erts_smp_atomic32_cmpxchg_mb(&p->state, n, e);
+	    if (a == e)
+		break;
+	}
+    }
+
     dep = ((p->flags & F_DISTRIBUTION)
 	   ? ERTS_PROC_SET_DIST_ENTRY(p, ERTS_PROC_LOCKS_ALL, NULL)
 	   : NULL);
@@ -9032,8 +8892,6 @@ continue_exit_process(Process *p
     ERTS_SMP_LC_ASSERT(curr_locks == erts_proc_lc_my_proc_locks(p));
     ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_MAIN & curr_locks);
 
-    ASSERT(p->status == P_EXITING);
-
     p->i = (BeamInstr *) beam_continue_exit;
 
     if (!(curr_locks & ERTS_PROC_LOCK_STATUS)) {
@@ -9041,8 +8899,6 @@ continue_exit_process(Process *p
 	curr_locks |= ERTS_PROC_LOCK_STATUS;
     }
 
-    erts_add_to_runq(p);
-
     if (curr_locks != ERTS_PROC_LOCK_MAIN)
 	erts_smp_proc_unlock(p, ~ERTS_PROC_LOCK_MAIN & curr_locks);
 
@@ -9054,33 +8910,15 @@ continue_exit_process(Process *p
 static void
 timeout_proc(Process* p)
 {
+    erts_aint32_t state;
     BeamInstr** pi = (BeamInstr **) p->def_arg_reg;
     p->i = *pi;
     p->flags |= F_TIMO;
     p->flags &= ~F_INSLPQUEUE;
 
-    switch (p->status) {
-    case P_GARBING:
-	switch (p->gcstatus) {
-	case P_SUSPENDED:
-	    goto suspended;
-	case P_WAITING:
-	    goto waiting;
-	default:
-	    break;
-	}
-	break;
-    case P_WAITING:
-    waiting:
-	erts_add_to_runq(p);
-	break;
-    case P_SUSPENDED:
-    suspended:
-	p->rstatus = P_RUNABLE;   /* MUST set resume status to runnable */
-	break;
-    default:
-	break;
-    }
+    state = erts_smp_atomic32_read_acqb(&p->state);
+    if (!(state & ERTS_PSFLG_ACTIVE))
+	schedule_process(p, state, 0);
 }
 
 
@@ -9148,6 +8986,7 @@ erts_stack_dump(int to, void *to_arg, Process *p)
 void
 erts_program_counter_info(int to, void *to_arg, Process *p)
 {
+    erts_aint32_t state;
     int i;
 
     erts_print(to, to_arg, "Program counter: %p (", p->i);
@@ -9156,7 +8995,8 @@ erts_program_counter_info(int to, void *to_arg, Process *p)
     erts_print(to, to_arg, "CP: %p (", p->cp);
     print_function_from_pc(to, to_arg, p->cp);
     erts_print(to, to_arg, ")\n");
-    if (!((p->status == P_RUNNING) || (p->status == P_GARBING))) {
+    state = erts_smp_atomic32_read_acqb(&p->state);
+    if (!(state & (ERTS_PSFLG_RUNNING|ERTS_PSFLG_GC))) {
         erts_print(to, to_arg, "arity = %d\n",p->arity);
 	if (!ERTS_IS_CRASH_DUMPING) {
 	    /*
diff --git a/erts/emulator/beam/erl_process.h b/erts/emulator/beam/erl_process.h
index d40f50c0af..249f29e7e6 100644
--- a/erts/emulator/beam/erl_process.h
+++ b/erts/emulator/beam/erl_process.h
@@ -112,28 +112,29 @@ extern int erts_sched_thread_suggested_stack_size;
 #define PRIORITY_NORMAL       2
 #define PRIORITY_LOW          3
 #define ERTS_NO_PROC_PRIO_LEVELS      4
+#define ERTS_NO_PROC_PRIO_QUEUES      3
 
 #define ERTS_PORT_PRIO_LEVEL ERTS_NO_PROC_PRIO_LEVELS
+#define ERTS_NO_PRIO_LEVELS (ERTS_NO_PROC_PRIO_LEVELS + 1)
 
 #define ERTS_RUNQ_FLGS_PROCS_QMASK \
   ((((Uint32) 1) << ERTS_NO_PROC_PRIO_LEVELS) - 1)
 
-#define ERTS_NO_PRIO_LEVELS (ERTS_NO_PROC_PRIO_LEVELS + 1)
-#define ERTS_RUNQ_FLGS_MIGRATE_QMASK \
+#define ERTS_RUNQ_FLGS_QMASK \
   ((((Uint32) 1) << ERTS_NO_PRIO_LEVELS) - 1)
 
 #define ERTS_RUNQ_FLGS_EMIGRATE_SHFT \
-  ERTS_NO_PROC_PRIO_LEVELS
+  ERTS_NO_PRIO_LEVELS
 #define ERTS_RUNQ_FLGS_IMMIGRATE_SHFT \
   (ERTS_RUNQ_FLGS_EMIGRATE_SHFT + ERTS_NO_PRIO_LEVELS)
 #define ERTS_RUNQ_FLGS_EVACUATE_SHFT \
   (ERTS_RUNQ_FLGS_IMMIGRATE_SHFT + ERTS_NO_PRIO_LEVELS)
 #define ERTS_RUNQ_FLGS_EMIGRATE_QMASK \
-  (ERTS_RUNQ_FLGS_MIGRATE_QMASK << ERTS_RUNQ_FLGS_EMIGRATE_SHFT)
+  (ERTS_RUNQ_FLGS_QMASK << ERTS_RUNQ_FLGS_EMIGRATE_SHFT)
 #define ERTS_RUNQ_FLGS_IMMIGRATE_QMASK \
-  (ERTS_RUNQ_FLGS_MIGRATE_QMASK << ERTS_RUNQ_FLGS_IMMIGRATE_SHFT)
+  (ERTS_RUNQ_FLGS_QMASK << ERTS_RUNQ_FLGS_IMMIGRATE_SHFT)
 #define ERTS_RUNQ_FLGS_EVACUATE_QMASK \
-  (ERTS_RUNQ_FLGS_MIGRATE_QMASK << ERTS_RUNQ_FLGS_EVACUATE_SHFT)
+  (ERTS_RUNQ_FLGS_QMASK << ERTS_RUNQ_FLGS_EVACUATE_SHFT)
 
 #define ERTS_RUNQ_FLG_BASE2 \
   (ERTS_RUNQ_FLGS_EVACUATE_SHFT + ERTS_NO_PRIO_LEVELS)
@@ -148,14 +149,18 @@ extern int erts_sched_thread_suggested_stack_size;
   (((Uint32) 1) << (ERTS_RUNQ_FLG_BASE2 + 3))
 #define ERTS_RUNQ_FLG_INACTIVE \
   (((Uint32) 1) << (ERTS_RUNQ_FLG_BASE2 + 4))
+#define ERTS_RUNQ_FLG_NONEMPTY \
+  (((Uint32) 1) << (ERTS_RUNQ_FLG_BASE2 + 5))
+#define ERTS_RUNQ_FLG_PROTECTED \
+  (((Uint32) 1) << (ERTS_RUNQ_FLG_BASE2 + 6))
 
 #define ERTS_RUNQ_FLGS_MIGRATION_QMASKS	\
   (ERTS_RUNQ_FLGS_EMIGRATE_QMASK	\
    | ERTS_RUNQ_FLGS_IMMIGRATE_QMASK	\
    | ERTS_RUNQ_FLGS_EVACUATE_QMASK)
+
 #define ERTS_RUNQ_FLGS_MIGRATION_INFO \
-  (ERTS_RUNQ_FLGS_MIGRATION_QMASKS \
-   | ERTS_RUNQ_FLG_INACTIVE \
+  (ERTS_RUNQ_FLG_INACTIVE \
    | ERTS_RUNQ_FLG_OUT_OF_WORK \
    | ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK)
 
@@ -186,33 +191,45 @@ extern int erts_sched_thread_suggested_stack_size;
 #define ERTS_UNSET_RUNQ_FLG_EVACUATE(FLGS, PRIO) \
   ((FLGS) &= ~ERTS_RUNQ_FLG_EVACUATE((PRIO)))
 
-#define ERTS_RUNQ_IFLG_SUSPENDED		(((erts_aint32_t) 1) << 0)
-#define ERTS_RUNQ_IFLG_NONEMPTY			(((erts_aint32_t) 1) << 1)
-
-
-#ifdef DEBUG
-#  if defined(ARCH_64) && !HALFWORD_HEAP
-#    define ERTS_DBG_SET_INVALID_RUNQP(RQP, N) \
-       (*((char **) &(RQP)) = (char *) (0xdeadbeefdead0003 | ((N) << 4)))
-#  define ERTS_DBG_VERIFY_VALID_RUNQP(RQP) \
-do { \
-    ASSERT((RQP) != NULL); \
-    ASSERT(((((Uint) (RQP)) & ((Uint) 0x3))) == ((Uint) 0)); \
-    ASSERT((((Uint) (RQP)) & ~((Uint) 0xffff)) != ((Uint) 0xdeadbeefdead0000));\
-} while (0)
-#  else
-#    define ERTS_DBG_SET_INVALID_RUNQP(RQP, N) \
-       (*((char **) &(RQP)) = (char *) (0xdead0003 | ((N) << 4)))
-#  define ERTS_DBG_VERIFY_VALID_RUNQP(RQP) \
-do { \
-    ASSERT((RQP) != NULL); \
-    ASSERT(((((UWord) (RQP)) & ((UWord) 1))) == ((UWord) 0)); \
-    ASSERT((((UWord) (RQP)) & ~((UWord) 0xffff)) != ((UWord) 0xdead0000)); \
-} while (0)
-#  endif
-#else
-#  define ERTS_DBG_SET_INVALID_RUNQP(RQP, N)
-#  define ERTS_DBG_VERIFY_VALID_RUNQP(RQP)
+#define ERTS_RUNQ_FLGS_INIT(RQ, INIT)					\
+    erts_smp_atomic32_init_nob(&(RQ)->flags, (erts_aint32_t) (INIT))
+#define ERTS_RUNQ_FLGS_SET(RQ, FLGS)					\
+    ((Uint32) erts_smp_atomic32_read_bor_relb(&(RQ)->flags,		\
+					      (erts_aint32_t) (FLGS)))
+#define ERTS_RUNQ_FLGS_UNSET(RQ, FLGS)					\
+    ((Uint32) erts_smp_atomic32_read_band_relb(&(RQ)->flags,		\
+					       (erts_aint32_t) ~(FLGS)))
+#define ERTS_RUNQ_FLGS_GET(RQ)						\
+    ((Uint32) erts_smp_atomic32_read_acqb(&(RQ)->flags))
+#define ERTS_RUNQ_FLGS_GET_NOB(RQ)					\
+    ((Uint32) erts_smp_atomic32_read_nob(&(RQ)->flags))
+#define ERTS_RUNQ_FLGS_GET_MB(RQ)					\
+    ((Uint32) erts_smp_atomic32_read_mb(&(RQ)->flags))
+#define ERTS_RUNQ_FLGS_MASK_SET(RQ, MSK, FLGS)		  		\
+    ((Uint32) erts_smp_atomic32_mask_set_relb(&(RQ)->flags, 		\
+					      (erts_aint32_t) (MSK),	\
+					      (erts_aint32_t) (FLGS)))
+
+ERTS_GLB_INLINE erts_aint32_t
+erts_smp_atomic32_mask_set_relb(erts_smp_atomic32_t *a32p,
+				erts_aint32_t mask,
+				erts_aint32_t set);
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint32_t
+erts_smp_atomic32_mask_set_relb(erts_smp_atomic32_t *a32p,
+				erts_aint32_t mask,
+				erts_aint32_t set)
+{
+    erts_aint32_t act = erts_smp_atomic32_read_nob(a32p);
+    while (1) {
+	erts_aint32_t exp = act;
+	erts_aint32_t new = exp & ~mask;
+	new |= (mask & set);
+	act = erts_smp_atomic32_cmpxchg_relb(a32p, new, exp);
+	if (act == exp)
+	    return act;
+    }
+}	
 #endif
 
 typedef enum {
@@ -311,21 +328,39 @@ typedef struct ErtsSchedulerData_ ErtsSchedulerData;
 typedef struct ErtsRunQueue_ ErtsRunQueue;
 
 typedef struct {
-    int len;
-    int max_len;
+    erts_smp_atomic32_t len;
+    erts_aint32_t max_len;
     int reds;
+} ErtsRunQueueInfo;
+
+#ifdef ERTS_SMP
+
+typedef struct {
+    Uint32 flags;
+    ErtsRunQueue *misc_evac_runq;
     struct {
 	struct {
 	    int this;
 	    int other;
 	} limit;
 	ErtsRunQueue *runq;
-    } migrate;
-} ErtsRunQueueInfo;
+	Uint32 flags;
+    } prio[ERTS_NO_PRIO_LEVELS];
+} ErtsMigrationPath;
+
+typedef struct ErtsMigrationPaths_ ErtsMigrationPaths;
+
+struct ErtsMigrationPaths_ {
+    void *block;
+    ErtsMigrationPaths *next;
+    ErtsThrPrgrVal thr_prgr;
+    ErtsMigrationPath mpath[1];
+};
+
+#endif /* ERTS_SMP */
 
 struct ErtsRunQueue_ {
     int ix;
-    erts_smp_atomic32_t info_flags;
 
     erts_smp_mtx_t mtx;
     erts_smp_cnd_t cnd;
@@ -333,19 +368,18 @@ struct ErtsRunQueue_ {
     ErtsSchedulerData *scheduler;
     int waiting; /* < 0 in sys schedule; > 0 on cnd variable */
     int woken;
-    Uint32 flags;
+    erts_smp_atomic32_t flags;
     int check_balance_reds;
     int full_reds_history_sum;
     int full_reds_history[ERTS_FULL_REDS_HISTORY_SIZE];
     int out_of_work_count;
-    int max_len;
-    int len;
+    erts_aint32_t max_len;
+    erts_aint32_t len;
     int wakeup_other;
     int wakeup_other_reds;
     int halt_in_progress;
 
     struct {
-	int len;
 	ErtsProcList *pending_exiters;
 	Uint context_switches;
 	Uint reductions;
@@ -360,7 +394,7 @@ struct ErtsRunQueue_ {
     struct {
 	ErtsMiscOpList *start;
 	ErtsMiscOpList *end;
-	ErtsRunQueue *evac_runq;
+	erts_smp_atomic_t evac_runq;
     } misc;
 
     struct {
@@ -380,7 +414,7 @@ extern ErtsAlignedRunQueue *erts_aligned_run_queues;
 #define ERTS_PROC_REDUCTIONS_EXECUTED(RQ, PRIO, REDS, AREDS)	\
 do {								\
     (RQ)->procs.reductions += (AREDS);				\
-    (RQ)->procs.prio_info[p->prio].reds += (REDS);		\
+    (RQ)->procs.prio_info[(PRIO)].reds += (REDS);		\
     (RQ)->check_balance_reds -= (REDS);				\
     (RQ)->wakeup_other_reds += (AREDS);				\
 } while (0)
@@ -488,6 +522,90 @@ extern ErtsAlignedSchedulerData *erts_aligned_scheduler_data;
 extern ErtsSchedulerData *erts_scheduler_data;
 #endif
 
+#if defined(ERTS_SMP) && defined(ERTS_ENABLE_LOCK_CHECK)
+int erts_smp_lc_runq_is_locked(ErtsRunQueue *);
+#endif
+
+#ifdef ERTS_INCLUDE_SCHEDULER_INTERNALS
+
+/*
+ * Run queue locked during modifications. We use atomic ops since
+ * other threads peek at values without run queue lock.
+ */
+
+ERTS_GLB_INLINE void erts_smp_inc_runq_len(ErtsRunQueue *rq, ErtsRunQueueInfo *rqi, int prio);
+ERTS_GLB_INLINE void erts_smp_dec_runq_len(ErtsRunQueue *rq, ErtsRunQueueInfo *rqi, int prio);
+ERTS_GLB_INLINE void erts_smp_reset_max_len(ErtsRunQueue *rq, ErtsRunQueueInfo *rqi);
+
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+
+ERTS_GLB_INLINE void
+erts_smp_inc_runq_len(ErtsRunQueue *rq, ErtsRunQueueInfo *rqi, int prio)
+{
+    erts_aint32_t len;
+
+    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(rq));
+
+    len = erts_smp_atomic32_read_nob(&rqi->len);
+    ASSERT(len >= 0);
+    if (len == 0) {
+	ASSERT((erts_smp_atomic32_read_nob(&rq->flags)
+		& ((erts_aint32_t) (1 << prio))) == 0);
+	erts_smp_atomic32_read_bor_nob(&rq->flags,
+				       (erts_aint32_t) (1 << prio));
+    }
+    len++;
+    if (rqi->max_len < len)
+	rqi->max_len = len;
+
+    erts_smp_atomic32_set_relb(&rqi->len, len);
+
+    rq->len++;
+    if (rq->max_len < rq->len)
+	rq->max_len = len;
+    ASSERT(rq->len > 0);
+}
+
+ERTS_GLB_INLINE void
+erts_smp_dec_runq_len(ErtsRunQueue *rq, ErtsRunQueueInfo *rqi, int prio)
+{
+    erts_aint32_t len;
+
+    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(rq));
+
+    len = erts_smp_atomic32_read_nob(&rqi->len);
+    len--;
+    ASSERT(len >= 0);
+    if (len == 0) {
+	ASSERT((erts_smp_atomic32_read_nob(&rq->flags)
+		& ((erts_aint32_t) (1 << prio))));
+	erts_smp_atomic32_read_band_nob(&rq->flags,
+					~((erts_aint32_t) (1 << prio)));
+    }
+    erts_smp_atomic32_set_relb(&rqi->len, len);
+
+    rq->len--;
+    ASSERT(rq->len >= 0);
+}
+
+ERTS_GLB_INLINE void
+erts_smp_reset_max_len(ErtsRunQueue *rq, ErtsRunQueueInfo *rqi)
+{
+    erts_aint32_t len;
+
+    ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(rq));
+
+    len = erts_smp_atomic32_read_nob(&rqi->len);
+    ASSERT(rqi->max_len >= len);
+    rqi->max_len = len;
+}
+
+#endif /* ERTS_GLB_INLINE_INCL_FUNC_DEF */
+
+#define RUNQ_READ_LEN(X) erts_smp_atomic32_read_nob((X))
+
+#endif /* ERTS_INCLUDE_SCHEDULER_INTERNALS */
+
 /*
  * Process Specific Data.
  *
@@ -644,12 +762,9 @@ struct process {
 				 * Number of reductions left to execute.
 				 * Only valid for the current process.
 				 */
-    Uint32 status;		/* process STATE */
-    Uint32 gcstatus;		/* process gc STATE */
-    Uint32 rstatus;		/* process resume STATE */
     Uint32 rcount;		/* suspend count */
     int  prio;			/* Priority of process */
-    int  skipped;		/* Times a low prio process has been rescheduled */
+    int  schedule_count;	/* Times left to reschedule a low prio process */
     Uint reds;			/* No of reductions for this process  */
     Eterm tracer_proc;		/* If proc is traced, this is the tracer
 				   (can NOT be boxed) */
@@ -662,7 +777,6 @@ struct process {
     Eterm ftrace;		/* Latest exception stack trace dump */
 
     Process *next;		/* Pointer to next process in run queue */
-    Process *prev;		/* Pointer to prev process in run queue */
 
     struct reg_proc *reg;	/* NULL iff not registered */
     ErtsLink *nlinks;
@@ -732,19 +846,16 @@ struct process {
 	void *exit_data;	/* Misc data referred during termination */
     } u;
 
-    ErtsRunQueue *bound_runq;
+    erts_smp_atomic32_t state;  /* Process state flags (see ERTS_PSFLG_*) */
 
 #ifdef ERTS_SMP
     erts_proc_lock_t lock;
-    erts_atomic32_t aflags;
     ErtsSchedulerData *scheduler_data;
-    Uint32 runq_flags;
-    Uint32 status_flags;
     ErlMessageInQueue msg_inq;
     Eterm suspendee;
     ErtsPendingSuspend *pending_suspenders;
     ErtsPendExit pending_exit;
-    ErtsRunQueue *run_queue;
+    erts_smp_atomic_t run_queue;
 #ifdef HIPE
     struct hipe_process_state_smp hipe_smp;
 #endif
@@ -816,8 +927,27 @@ void erts_check_for_holes(Process* p);
 
 #define SEQ_TRACE_TOKEN(p)  ((p)->seq_trace_token)
 
-#define ERTS_PROC_AFLG_EXITING		(((erts_aint_t) 1) << 0)
-#define ERTS_PROC_AFLG_PENDING_EXIT	(((erts_aint_t) 1) << 1)
+#if ERTS_NO_PROC_PRIO_LEVELS > 4
+#  error "Need to increase ERTS_PSFLG_PRIO_SHIFT"
+#endif
+
+#define ERTS_PSFLG_PRIO_SHIFT 2
+
+#define ERTS_PSFLG_BIT(N) \
+    (((erts_aint32_t) 1) << (ERTS_PSFLG_PRIO_SHIFT + (N)))
+
+#define ERTS_PSFLG_PRIO_MASK 		(ERTS_PSFLG_BIT(0) - 1)
+
+#define ERTS_PSFLG_FREE			ERTS_PSFLG_BIT(0)
+#define ERTS_PSFLG_EXITING		ERTS_PSFLG_BIT(1)
+#define ERTS_PSFLG_PENDING_EXIT		ERTS_PSFLG_BIT(2)
+#define ERTS_PSFLG_ACTIVE		ERTS_PSFLG_BIT(3)
+#define ERTS_PSFLG_IN_RUNQ		ERTS_PSFLG_BIT(4)
+#define ERTS_PSFLG_RUNNING		ERTS_PSFLG_BIT(5)
+#define ERTS_PSFLG_SUSPENDED		ERTS_PSFLG_BIT(6)
+#define ERTS_PSFLG_GC			ERTS_PSFLG_BIT(7)
+#define ERTS_PSFLG_BOUND		ERTS_PSFLG_BIT(8)
+#define ERTS_PSFLG_TRAP_EXIT		ERTS_PSFLG_BIT(9)
 
 
 /* The sequential tracing token is a tuple of size 5:
@@ -925,17 +1055,13 @@ struct erts_system_profile_flags_t {
     unsigned int exclusive : 1;
 };
 extern struct erts_system_profile_flags_t erts_system_profile_flags;
-
-#define INVALID_PID(p, pid)	((p) == NULL				\
-				 || (p)->id != (pid)			\
-				 || (p)->status == P_EXITING)
  
 #define IS_TRACED(p)             ( (p)->tracer_proc != NIL )
 #define ARE_TRACE_FLAGS_ON(p,tf) ( ((p)->trace_flags & (tf|F_SENSITIVE)) == (tf) )
 #define IS_TRACED_FL(p,tf)       ( IS_TRACED(p) && ARE_TRACE_FLAGS_ON(p,tf) )
 
 /* process flags */
-#define F_TRAPEXIT           (1 <<  0)
+#define F_HIBERNATE_SCHED    (1 <<  0) /* Schedule out after hibernate op */
 #define F_INSLPQUEUE         (1 <<  1) /* Set if in timer queue */
 #define F_TIMO               (1 <<  2) /* Set if timeout */
 #define F_HEAP_GROW          (1 <<  3)
@@ -946,7 +1072,6 @@ extern struct erts_system_profile_flags_t erts_system_profile_flags;
 #define F_HAVE_BLCKD_MSCHED  (1 <<  8) /* Process has blocked multi-scheduling */
 #define F_P2PNR_RESCHED      (1 <<  9) /* Process has been rescheduled via erts_pid2proc_not_running() */
 #define F_FORCE_GC           (1 << 10) /* Force gc at process in-scheduling */
-#define F_HIBERNATE_SCHED    (1 << 11) /* Schedule out after hibernate op */
 
 /* process trace_flags */
 #define F_SENSITIVE          (1 << 0)
@@ -1013,67 +1138,10 @@ extern struct erts_system_profile_flags_t erts_system_profile_flags;
 #define DT_UTAG_FLAGS(P)  ((P)->dt_utag_flags) 
 #endif
 
-
-#ifdef ERTS_SMP
-/* Status flags ... */
-#define ERTS_PROC_SFLG_PENDADD2SCHEDQ	(((Uint32) 1) << 0)	/* Pending
-								   add to
-								   schedule q */
-#define ERTS_PROC_SFLG_INRUNQ		(((Uint32) 1) << 1)	/* Process is
-								   in run q */
-#define ERTS_PROC_SFLG_TRAPEXIT		(((Uint32) 1) << 2)	/* Process is
-								   trapping
-								   exit */
-#define ERTS_PROC_SFLG_RUNNING		(((Uint32) 1) << 3)	/* Process is
-								   running */
-/* Scheduler flags in process struct... */
-#define ERTS_PROC_RUNQ_FLG_RUNNING	(((Uint32) 1) << 0)	/* Process is
-								   running */
-
-#endif
-
-
-#ifdef ERTS_SMP
-#define ERTS_PROC_IS_TRAPPING_EXITS(P)					\
-  (ERTS_SMP_LC_ASSERT(erts_proc_lc_my_proc_locks((P))			\
-		      & ERTS_PROC_LOCK_STATUS),				\
-   (P)->status_flags & ERTS_PROC_SFLG_TRAPEXIT)
-
-#define ERTS_PROC_SET_TRAP_EXIT(P)					\
-  (ERTS_SMP_LC_ASSERT(((ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_STATUS)	\
-		       & erts_proc_lc_my_proc_locks((P)))		\
-		      == (ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_STATUS)),	\
-   (P)->status_flags |= ERTS_PROC_SFLG_TRAPEXIT,			\
-   (P)->flags |= F_TRAPEXIT,						\
-   1)
-
-#define ERTS_PROC_UNSET_TRAP_EXIT(P)					\
-  (ERTS_SMP_LC_ASSERT(((ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_STATUS)	\
-		       & erts_proc_lc_my_proc_locks((P)))		\
-		      == (ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_STATUS)),	\
-   (P)->status_flags &= ~ERTS_PROC_SFLG_TRAPEXIT,			\
-   (P)->flags &= ~F_TRAPEXIT,						\
-   0)
-#else
-#define ERTS_PROC_IS_TRAPPING_EXITS(P) ((P)->flags & F_TRAPEXIT)
-#define ERTS_PROC_SET_TRAP_EXIT(P) ((P)->flags |= F_TRAPEXIT, 1)
-#define ERTS_PROC_UNSET_TRAP_EXIT(P) ((P)->flags &= ~F_TRAPEXIT, 0)
-#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)
 
-
-/* Process status values */
-#define P_FREE      0
-#define P_RUNABLE   1
-#define P_WAITING   2
-#define P_RUNNING   3
-#define P_EXITING   4
-#define P_GARBING   5
-#define P_SUSPENDED 6
-
 #define CANCEL_TIMER(p) \
     do { \
 	if ((p)->flags & (F_INSLPQUEUE)) \
@@ -1151,14 +1219,6 @@ Eterm erts_get_schedulers_binds(Process *c_p);
 Eterm erts_set_cpu_topology(Process *c_p, Eterm term);
 Eterm erts_bind_schedulers(Process *c_p, Eterm how);
 ErtsRunQueue *erts_schedid2runq(Uint);
-#ifdef ERTS_SMP
-ErtsMigrateResult erts_proc_migrate(Process *,
-				    ErtsProcLocks *,
-				    ErtsRunQueue *,
-				    int *,
-				    ErtsRunQueue *,
-				    int *);
-#endif
 Process *schedule(Process*, int);
 void erts_schedule_misc_op(void (*)(void *), void *);
 Eterm erl_create_process(Process*, Eterm, Eterm, Eterm, ErlSpawnOpts*);
@@ -1207,8 +1267,7 @@ int erts_send_exit_signal(Process *,
 #ifdef ERTS_SMP
 void erts_handle_pending_exit(Process *, ErtsProcLocks);
 #define ERTS_PROC_PENDING_EXIT(P) \
-  (ERTS_SMP_LC_ASSERT(erts_proc_lc_my_proc_locks((P)) & ERTS_PROC_LOCK_STATUS),\
-   (P)->pending_exit.reason != THE_NON_VALUE)
+    (ERTS_PSFLG_PENDING_EXIT & erts_smp_atomic32_read_acqb(&(P)->state))
 #else
 #define ERTS_PROC_PENDING_EXIT(P) 0
 #endif
@@ -1260,13 +1319,26 @@ ErtsSchedulerData *erts_get_scheduler_data(void)
 #endif
 #endif
 
+void erts_schedule_process(Process *, erts_aint32_t);
+
+ERTS_GLB_INLINE void erts_proc_notify_new_message(Process *p);
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE void
+erts_proc_notify_new_message(Process *p)
+{
+    /* No barrier needed, due to msg lock */
+    erts_aint32_t state = erts_smp_atomic32_read_nob(&p->state);
+    if (!(state & ERTS_PSFLG_ACTIVE))
+	erts_schedule_process(p, state);
+}
+#endif
+
 #if defined(ERTS_SMP) && defined(ERTS_ENABLE_LOCK_CHECK)
 
 #define ERTS_PROCESS_LOCK_ONLY_LOCK_CHECK_PROTO__
 #include "erl_process_lock.h"
 #undef ERTS_PROCESS_LOCK_ONLY_LOCK_CHECK_PROTO__
 
-int erts_smp_lc_runq_is_locked(ErtsRunQueue *);
 #define ERTS_SMP_LC_CHK_RUNQ_LOCK(RQ, L)				\
 do {									\
     if ((L))								\
@@ -1392,13 +1464,91 @@ erts_proc_set_error_handler(Process *p, ErtsProcLocks plocks, Eterm handler)
 
 #endif
 
+#ifdef ERTS_INCLUDE_SCHEDULER_INTERNALS
+
 #ifdef ERTS_SMP
-ErtsRunQueue *erts_prepare_emigrate(ErtsRunQueue *c_rq,
-				    ErtsRunQueueInfo *c_rqi,
-				    int prio);
 
+#include "erl_thr_progress.h"
+
+extern erts_atomic_t erts_migration_paths;
+
+ERTS_GLB_INLINE ErtsMigrationPaths *erts_get_migration_paths_managed(void);
+ERTS_GLB_INLINE ErtsMigrationPaths *erts_get_migration_paths(void);
 ERTS_GLB_INLINE ErtsRunQueue *erts_check_emigration_need(ErtsRunQueue *c_rq,
 							 int prio);
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+
+ERTS_GLB_INLINE ErtsMigrationPaths *
+erts_get_migration_paths_managed(void)
+{
+    return (ErtsMigrationPaths *) erts_atomic_read_ddrb(&erts_migration_paths);
+}
+
+ERTS_GLB_INLINE ErtsMigrationPaths *
+erts_get_migration_paths(void)
+{
+    if (erts_thr_progress_is_managed_thread())
+	return erts_get_migration_paths_managed();
+    else
+	return NULL;
+}
+
+ERTS_GLB_INLINE ErtsRunQueue *
+erts_check_emigration_need(ErtsRunQueue *c_rq, int prio)
+{
+    ErtsMigrationPaths *mps = erts_get_migration_paths();
+    ErtsMigrationPath *mp;
+    Uint32 flags;
+
+    if (!mps)
+	return NULL;
+
+    mp = &mps->mpath[c_rq->ix];
+    flags = mp->flags;
+
+    if (ERTS_CHK_RUNQ_FLG_EMIGRATE(flags, prio)) {
+	int len;
+
+	if (ERTS_CHK_RUNQ_FLG_EVACUATE(flags, prio)) {
+	    /* force emigration */
+	    return mp->prio[prio].runq;
+	}
+
+	if (flags & ERTS_RUNQ_FLG_INACTIVE) {
+	    /*
+	     * Run queue was inactive at last balance. Verify that
+	     * it still is before forcing emigration.
+	     */
+	    if (ERTS_RUNQ_FLGS_GET(c_rq) & ERTS_RUNQ_FLG_INACTIVE)
+		return mp->prio[prio].runq;
+	}
+
+
+	if (prio == ERTS_PORT_PRIO_LEVEL)
+	    len = RUNQ_READ_LEN(&c_rq->ports.info.len);
+	else
+	    len = RUNQ_READ_LEN(&c_rq->procs.prio_info[prio].len);
+
+	if (len > mp->prio[prio].limit.this) {
+	    ErtsRunQueue *n_rq = mp->prio[prio].runq;
+	    if (n_rq) {
+		if (prio == ERTS_PORT_PRIO_LEVEL)
+		    len = RUNQ_READ_LEN(&n_rq->ports.info.len);
+		else
+		    len = RUNQ_READ_LEN(&n_rq->procs.prio_info[prio].len);
+
+		if (len < mp->prio[prio].limit.other)
+		    return n_rq;
+	    }
+	}
+    }
+    return NULL;
+}
+
+#endif
+
+#endif
+
 #endif
 
 ERTS_GLB_INLINE int erts_is_scheduler_bound(ErtsSchedulerData *esdp);
@@ -1417,29 +1567,6 @@ ERTS_GLB_INLINE void erts_smp_runqs_unlock(ErtsRunQueue *rq1, ErtsRunQueue *rq2)
 
 #if ERTS_GLB_INLINE_INCL_FUNC_DEF
 
-#ifdef ERTS_SMP
-ERTS_GLB_INLINE ErtsRunQueue *
-erts_check_emigration_need(ErtsRunQueue *c_rq, int prio)
-{
-    ErtsRunQueueInfo *c_rqi;
-
-    if (!ERTS_CHK_RUNQ_FLG_EMIGRATE(c_rq->flags, prio))
-	return NULL;
-
-    if (prio == ERTS_PORT_PRIO_LEVEL)
-	c_rqi = &c_rq->ports.info;
-    else
-	c_rqi = &c_rq->procs.prio_info[prio];
-
-    if (!ERTS_CHK_RUNQ_FLG_EVACUATE(c_rq->flags, prio)
-	&& !(c_rq->flags & ERTS_RUNQ_FLG_INACTIVE)
-	&& c_rqi->len <= c_rqi->migrate.limit.this)
-	return NULL;
-
-    return erts_prepare_emigrate(c_rq, c_rqi, prio);
-}
-#endif
-
 ERTS_GLB_INLINE
 int erts_is_scheduler_bound(ErtsSchedulerData *esdp)
 {
@@ -1477,10 +1604,9 @@ Uint erts_get_scheduler_id(void)
 ERTS_GLB_INLINE ErtsRunQueue *
 erts_get_runq_proc(Process *p)
 {
-    ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p));
 #ifdef ERTS_SMP
-    ASSERT(p->run_queue);
-    return p->run_queue;
+    ASSERT(ERTS_AINT_NULL != erts_atomic_read_nob(&p->run_queue));
+    return (ErtsRunQueue *) erts_atomic_read_nob(&p->run_queue);
 #else
     return ERTS_RUNQ_IX(0);
 #endif
@@ -1614,10 +1740,6 @@ Process *erts_pid2proc_nropt(Process *c_p,
 			     ErtsProcLocks pid_locks);
 extern int erts_disable_proc_not_running_opt;
 
-
-#define ERTS_PROC_IS_EXITING(P) \
-    (ERTS_PROC_AFLG_EXITING & erts_atomic32_read_acqb(&(P)->aflags))
-
 #ifdef DEBUG
 #define ERTS_SMP_ASSERT_IS_NOT_EXITING(P) \
     do { ASSERT(!ERTS_PROC_IS_EXITING((P))); } while (0)
@@ -1627,8 +1749,6 @@ extern int erts_disable_proc_not_running_opt;
 
 #else /* !ERTS_SMP */
 
-#define ERTS_PROC_IS_EXITING(P) ((P)->status == P_EXITING)
-
 #define ERTS_SMP_ASSERT_IS_NOT_EXITING(P)
 
 #define erts_pid2proc_not_running erts_pid2proc
@@ -1636,6 +1756,10 @@ extern int erts_disable_proc_not_running_opt;
 
 #endif
 
+#define ERTS_PROC_IS_EXITING(P) \
+    (ERTS_PSFLG_EXITING & erts_smp_atomic32_read_acqb(&(P)->state))
+
+
 /* Minimum NUMBER of processes for a small system to start */
 #ifdef ERTS_SMP
 #define ERTS_MIN_PROCESSES		ERTS_NO_OF_PIX_LOCKS
diff --git a/erts/emulator/beam/erl_process_dump.c b/erts/emulator/beam/erl_process_dump.c
index 37cc717156..964dc1ae3e 100644
--- a/erts/emulator/beam/erl_process_dump.c
+++ b/erts/emulator/beam/erl_process_dump.c
@@ -67,11 +67,9 @@ erts_deep_process_dump(int to, void *to_arg)
     for (i = 0; i < erts_max_processes; i++) {
 	Process *p = erts_pix2proc(i);
 	if (p && p->i != ENULL) {
-	   if (p->status != P_EXITING) {
-	       if (p->status != P_GARBING) {
-		   dump_process_info(to, to_arg, p);
-	       }
-	   }
+	    erts_aint32_t state = erts_smp_atomic32_read_acqb(&p->state);
+	    if (!(state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_GC)))
+		dump_process_info(to, to_arg, p);
        }
     }
 
diff --git a/erts/emulator/beam/erl_process_lock.h b/erts/emulator/beam/erl_process_lock.h
index 9981af7a8a..015fda583e 100644
--- a/erts/emulator/beam/erl_process_lock.h
+++ b/erts/emulator/beam/erl_process_lock.h
@@ -129,11 +129,9 @@ typedef struct erts_proc_lock_t_ {
 /*
  * Status lock:
  *   Protects the following fields in the process structure:
- *   * status
- *   * rstatus
- *   * status_flags
  *   * pending_suspenders
  *   * suspendee
+ *   * ...
  */
 #define ERTS_PROC_LOCK_STATUS		(((ErtsProcLocks) 1) << ERTS_PROC_LOCK_MAX_BIT)
 
@@ -165,12 +163,11 @@ typedef struct erts_proc_lock_t_ {
  * Other rules regarding process locking:
  *
  * Exiting processes:
- *   When changing status to P_EXITING on a process, you are required
- *   to take all process locks (ERTS_PROC_LOCKS_ALL). Thus, by holding
- *   at least one process lock (whichever one doesn't matter) you
- *   are guaranteed that the process won't exit until the lock you are
- *   holding has been released. Appart from all process locks also
- *   the pix lock corresponding to the process has to be held.
+ *   When changing state to exiting (ERTS_PSFLG_EXITING) on a process,
+ *   you are required to take all process locks (ERTS_PROC_LOCKS_ALL).
+ *   Thus, by holding at least one process lock (whichever one doesn't
+ *   matter) you are guaranteed that the process won't exit until the
+ *   lock you are holding has been released.
  *
  * Lock order:
  *   Process locks with low numeric values has to be locked before
@@ -946,11 +943,11 @@ erts_pid2proc_opt(Process *c_p_unused,
 		  int flags)
 {
     Process *proc = erts_proc_lookup_raw(pid);
-    if (!(flags & ERTS_P2P_FLG_ALLOW_OTHER_X)
-	&& proc
-	&& proc->status == P_EXITING)
-	return NULL;
-    return proc;
+    return ((!(flags & ERTS_P2P_FLG_ALLOW_OTHER_X)
+	     && proc
+	     && ERTS_PROC_IS_EXITING(proc))
+	    ? NULL
+	    : proc);
 }
 #endif /* !ERTS_SMP */
 
diff --git a/erts/emulator/beam/erl_trace.c b/erts/emulator/beam/erl_trace.c
index a321bc504b..bc988cd61b 100644
--- a/erts/emulator/beam/erl_trace.c
+++ b/erts/emulator/beam/erl_trace.c
@@ -64,7 +64,7 @@ int erts_cpu_timestamp;
 #endif
 
 static erts_smp_mtx_t smq_mtx;
-static erts_smp_mtx_t sys_trace_mtx;
+static erts_smp_rwmtx_t sys_trace_rwmtx;
 
 enum ErtsSysMsgType {
     SYS_MSG_TYPE_UNDEFINED,
@@ -91,7 +91,12 @@ static void init_sys_msg_dispatcher(void);
 #endif
 
 void erts_init_trace(void) {
-    erts_smp_mtx_init(&sys_trace_mtx, "sys_tracers");
+    erts_smp_rwmtx_opt_t rwmtx_opts = ERTS_SMP_RWMTX_OPT_DEFAULT_INITER;
+    rwmtx_opts.type = ERTS_SMP_RWMTX_TYPE_EXTREMELY_FREQUENT_READ;
+    rwmtx_opts.lived = ERTS_SMP_RWMTX_LONG_LIVED;
+
+    erts_smp_rwmtx_init_opt(&sys_trace_rwmtx, &rwmtx_opts, "sys_tracers");
+
 #ifdef HAVE_ERTS_NOW_CPU
     erts_cpu_timestamp = 0;
 #endif
@@ -169,10 +174,10 @@ erts_system_profile_setup_active_schedulers(void)
     active_sched = erts_active_schedulers();
 }
 
-void
-erts_trace_check_exiting(Eterm exiting)
+static void
+exiting_reset(Eterm exiting)
 {
-    erts_smp_mtx_lock(&sys_trace_mtx);
+    erts_smp_rwmtx_rwlock(&sys_trace_rwmtx);
     if (exiting == default_tracer) {
 	default_tracer = NIL;
 	default_trace_flags &= TRACEE_FLAGS;
@@ -202,29 +207,49 @@ erts_trace_check_exiting(Eterm exiting)
 	erts_system_profile_clear(NULL);
 #endif
     }
-    erts_smp_mtx_unlock(&sys_trace_mtx);
+    erts_smp_rwmtx_rwunlock(&sys_trace_rwmtx);
+}
+
+void
+erts_trace_check_exiting(Eterm exiting)
+{
+    int reset = 0;
+    erts_smp_rwmtx_rlock(&sys_trace_rwmtx);
+    if (exiting == default_tracer)
+	reset = 1;
+    else if (exiting == system_seq_tracer)
+	reset = 1;
+    else if (exiting == system_monitor)
+	reset = 1;
+    else if (exiting == system_profile)
+	reset = 1;
+    erts_smp_rwmtx_runlock(&sys_trace_rwmtx);
+    if (reset)
+	exiting_reset(exiting);
+}
+
+static ERTS_INLINE int
+is_valid_tracer(Eterm tracer)
+{
+    return erts_proc_lookup(tracer) || erts_is_valid_tracer_port(tracer);
 }
 
 Eterm
 erts_set_system_seq_tracer(Process *c_p, ErtsProcLocks c_p_locks, Eterm new)
 {
-    Eterm old = THE_NON_VALUE;
+    Eterm old;
 
-    if (new != am_false) {
-	if (!erts_proc_lookup(new)
-	    && !erts_is_valid_tracer_port(new)) {
-	    return old;
-	}
-    }
+    if (new != am_false && !is_valid_tracer(new))
+	return THE_NON_VALUE;
 
-    erts_smp_mtx_lock(&sys_trace_mtx);
+    erts_smp_rwmtx_rwlock(&sys_trace_rwmtx);
     old = system_seq_tracer;
     system_seq_tracer = new;
 
 #ifdef DEBUG_PRINTOUTS
     erts_fprintf(stderr, "set seq tracer new=%T old=%T\n", new, old);
 #endif
-    erts_smp_mtx_unlock(&sys_trace_mtx);
+    erts_smp_rwmtx_rwunlock(&sys_trace_rwmtx);
     return old;
 }
 
@@ -232,12 +257,12 @@ Eterm
 erts_get_system_seq_tracer(void)
 {
     Eterm st;
-    erts_smp_mtx_lock(&sys_trace_mtx);
+    erts_smp_rwmtx_rlock(&sys_trace_rwmtx);
     st = system_seq_tracer;
 #ifdef DEBUG_PRINTOUTS
     erts_fprintf(stderr, "get seq tracer %T\n", st);
 #endif
-    erts_smp_mtx_unlock(&sys_trace_mtx);
+    erts_smp_rwmtx_runlock(&sys_trace_rwmtx);
     return st;
 }
 
@@ -270,7 +295,7 @@ get_default_tracing(Uint *flagsp, Eterm *tracerp)
 void
 erts_change_default_tracing(int setflags, Uint *flagsp, Eterm *tracerp)
 {
-    erts_smp_mtx_lock(&sys_trace_mtx);
+    erts_smp_rwmtx_rwlock(&sys_trace_rwmtx);
     if (flagsp) {
 	if (setflags)
 	    default_trace_flags |= *flagsp;
@@ -280,48 +305,48 @@ erts_change_default_tracing(int setflags, Uint *flagsp, Eterm *tracerp)
     if (tracerp)
 	default_tracer = *tracerp;
     get_default_tracing(flagsp, tracerp);
-    erts_smp_mtx_unlock(&sys_trace_mtx);
+    erts_smp_rwmtx_rwunlock(&sys_trace_rwmtx);
 }
 
 void
 erts_get_default_tracing(Uint *flagsp, Eterm *tracerp)
 {
-    erts_smp_mtx_lock(&sys_trace_mtx);
+    erts_smp_rwmtx_rlock(&sys_trace_rwmtx);
     get_default_tracing(flagsp, tracerp);
-    erts_smp_mtx_unlock(&sys_trace_mtx);
+    erts_smp_rwmtx_runlock(&sys_trace_rwmtx);
 }
 
 void
 erts_set_system_monitor(Eterm monitor)
 {
-    erts_smp_mtx_lock(&sys_trace_mtx);
+    erts_smp_rwmtx_rwlock(&sys_trace_rwmtx);
     system_monitor = monitor;
-    erts_smp_mtx_unlock(&sys_trace_mtx);
+    erts_smp_rwmtx_rwunlock(&sys_trace_rwmtx);
 }
 
 Eterm
 erts_get_system_monitor(void)
 {
     Eterm monitor;
-    erts_smp_mtx_lock(&sys_trace_mtx);
+    erts_smp_rwmtx_rlock(&sys_trace_rwmtx);
     monitor = system_monitor;
-    erts_smp_mtx_unlock(&sys_trace_mtx);
+    erts_smp_rwmtx_runlock(&sys_trace_rwmtx);
     return monitor;
 }
 
 /* Performance monitoring */
 void erts_set_system_profile(Eterm profile) {
-    erts_smp_mtx_lock(&sys_trace_mtx);
+    erts_smp_rwmtx_rwlock(&sys_trace_rwmtx);
     system_profile = profile;
-    erts_smp_mtx_unlock(&sys_trace_mtx);
+    erts_smp_rwmtx_rwunlock(&sys_trace_rwmtx);
 }
 
 Eterm
 erts_get_system_profile(void) {
     Eterm profile;
-    erts_smp_mtx_lock(&sys_trace_mtx);
+    erts_smp_rwmtx_rlock(&sys_trace_rwmtx);
     profile = system_profile;
-    erts_smp_mtx_unlock(&sys_trace_mtx);
+    erts_smp_rwmtx_runlock(&sys_trace_rwmtx);
     return profile;
 }
 
@@ -384,13 +409,9 @@ WRITE_SYS_MSG_TO_PORT(Eterm unused_to,
     }
 
 #ifndef ERTS_SMP
-    if (!INVALID_TRACER_PORT(trace_port, trace_port->id)) {
+    if (!INVALID_TRACER_PORT(trace_port, trace_port->id))
 #endif
 	erts_raw_port_command(trace_port, buffer, ptr-buffer);
-#ifndef ERTS_SMP
-	erts_port_release(trace_port);
-    }
-#endif
 
     erts_free(ERTS_ALC_T_TMP, (void *) buffer);
 }
@@ -465,13 +486,13 @@ send_to_port(Process *c_p, Eterm message,
 
     trace_port = NULL;
 #else
-    if (is_not_internal_port(*tracer_pid))
-	goto invalid_tracer_port;
 
-    trace_port = &erts_port[internal_port_index(*tracer_pid)];
+    trace_port = erts_id2port_sflgs(*tracer_pid,
+				    NULL,
+				    0,
+				    ERTS_PORT_SFLGS_INVALID_TRACER_LOOKUP);
 
-    if (INVALID_TRACER_PORT(trace_port, *tracer_pid)) {
-    invalid_tracer_port:
+    if (!trace_port) {
 	*tracee_flags &= ~TRACEE_FLAGS;
 	*tracer_pid = NIL;
 	return;
@@ -491,6 +512,7 @@ send_to_port(Process *c_p, Eterm message,
 			SYS_MSG_TYPE_TRACE,
 			message);
 #ifndef ERTS_SMP
+	erts_port_release(trace_port);
 	return;
     }
 
@@ -537,6 +559,9 @@ send_to_port(Process *c_p, Eterm message,
 	 */
 	do_send_schedfix_to_port(trace_port, c_p->id, ts);
     }
+
+    erts_port_release(trace_port);
+
     UnUseTmpHeapNoproc(LOCAL_HEAP_SIZE);
 #undef LOCAL_HEAP_SIZE
 #endif
@@ -566,15 +591,19 @@ profile_send(Eterm from, Eterm message) {
     	Port *profiler_port = NULL;
 
 	/* not smp */
-	
-	
-	profiler_port = &erts_port[internal_port_index(profiler)];
-	
-	do_send_to_port(profiler,
-			profiler_port,
-			NIL, /* or current process->id */
-			SYS_MSG_TYPE_SYSPROF,
-			message);
+
+	profiler_port = erts_id2port_sflgs(profiler,
+					   NULL,
+					   0,
+					   ERTS_PORT_SFLGS_INVALID_TRACER_LOOKUP);
+	if (profiler_port) {
+	    do_send_to_port(profiler,
+			    profiler_port,
+			    NIL, /* or current process->id */
+			    SYS_MSG_TYPE_SYSPROF,
+			    message);
+	    erts_port_release(profiler_port);
+	}
     	
     } else {
 	ASSERT(is_internal_pid(profiler)
@@ -627,13 +656,11 @@ seq_trace_send_to_port(Process *c_p,
 
     trace_port = NULL;
 #else
-    if (is_not_internal_port(seq_tracer))
-	goto invalid_tracer_port;
-
-    trace_port = &erts_port[internal_port_index(seq_tracer)];
-
-    if (INVALID_TRACER_PORT(trace_port, seq_tracer)) {
-    invalid_tracer_port:
+    trace_port = erts_id2port_sflgs(seq_tracer,
+				    NULL,
+				    0,
+				    ERTS_PORT_SFLGS_INVALID_TRACER_LOOKUP);
+    if (!trace_port) {
 	system_seq_tracer = am_false;
 #ifndef ERTS_SMP
 	UnUseTmpHeapNoproc(LOCAL_HEAP_SIZE);
@@ -651,6 +678,7 @@ seq_trace_send_to_port(Process *c_p,
 			message);
 
 #ifndef ERTS_SMP
+	erts_port_release(trace_port);
 	UnUseTmpHeapNoproc(LOCAL_HEAP_SIZE);
 	return;
     }
@@ -692,6 +720,9 @@ seq_trace_send_to_port(Process *c_p,
 	 */
 	do_send_schedfix_to_port(trace_port, c_p->id, ts);
     }
+
+    erts_port_release(trace_port);
+
     UnUseTmpHeapNoproc(LOCAL_HEAP_SIZE);
 #undef LOCAL_HEAP_SIZE
 #endif
@@ -790,13 +821,8 @@ trace_sched_aux(Process *p, Eterm what, int never_fake_sched)
 	ERTS_GET_TRACER_REF(tracer_ref, p->tracer_proc, p->trace_flags);
     }
 
-    if (ERTS_PROC_IS_EXITING(p)
-#ifndef ERTS_SMP
-	|| p->status == P_FREE
-#endif
-	) {
+    if (ERTS_PROC_IS_EXITING(p))
 	curr_func = 0;
-    }
     else {
 	if (!p->current)
 	    p->current = find_function_from_pc(p->i);
@@ -3148,10 +3174,10 @@ sys_msg_disp_failure(ErtsSysMsgQ *smqp, Eterm receiver)
 	break;
     case SYS_MSG_TYPE_SEQTRACE:
 	/* Reset seq_tracer if it hasn't changed */
-	erts_smp_mtx_lock(&sys_trace_mtx);
+	erts_smp_rwmtx_rwlock(&sys_trace_rwmtx);
 	if (system_seq_tracer == receiver)
 	    system_seq_tracer = am_false;
-	erts_smp_mtx_unlock(&sys_trace_mtx);
+	erts_smp_rwmtx_rwunlock(&sys_trace_rwmtx);
 	break;
     case SYS_MSG_TYPE_SYSMON:
 	if (receiver == NIL
@@ -3406,12 +3432,12 @@ sys_msg_dispatcher_func(void *unused)
 		    goto queue_proc_msg;
 	    }
 	    else if (is_internal_port(receiver)) {
-		port = erts_id2port(receiver, NULL, 0);
-		if (INVALID_TRACER_PORT(port, receiver)) {
-		    if (port)
-			erts_port_release(port);
+		port = erts_id2port_sflgs(receiver,
+					  NULL,
+					  0,
+					  ERTS_PORT_SFLGS_INVALID_TRACER_LOOKUP);
+		if (!port)
 		    goto failure;
-		}
 		else {
 		    write_sys_msg_to_port(receiver,
 					  port,
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index ded9646800..e9dbba3d4a 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -143,8 +143,8 @@ typedef struct ErtsXPortsList_ ErtsXPortsList;
 struct port {
     ErtsPortTaskSched sched;
     ErtsPortTaskHandle timeout_task;
-#ifdef ERTS_SMP
     erts_smp_atomic_t refc;
+#ifdef ERTS_SMP
     erts_smp_mtx_t *lock;
     ErtsXPortsList *xports;
     erts_smp_atomic_t run_queue;
@@ -196,6 +196,8 @@ erts_port_runq(Port *prt)
 #ifdef ERTS_SMP
     ErtsRunQueue *rq1, *rq2;
     rq1 = (ErtsRunQueue *) erts_smp_atomic_read_nob(&prt->run_queue);
+    if (!rq1)
+	return NULL;
     while (1) {
 	erts_smp_runq_lock(rq1);
 	rq2 = (ErtsRunQueue *) erts_smp_atomic_read_nob(&prt->run_queue);
@@ -203,6 +205,8 @@ erts_port_runq(Port *prt)
 	    return rq1;
 	erts_smp_runq_unlock(rq1);
 	rq1 = rq2;
+	if (!rq1)
+	    return NULL;
     }
 #else
     return ERTS_RUNQ_IX(0);
@@ -1220,28 +1224,29 @@ erts_smp_port_state_unlock(Port *prt)
 ERTS_GLB_INLINE int
 erts_smp_port_trylock(Port *prt)
 {
-#ifdef ERTS_SMP
     int res;
 
     ASSERT(erts_smp_atomic_read_nob(&prt->refc) > 0);
     erts_smp_atomic_inc_nob(&prt->refc);
+
+#ifdef ERTS_SMP
     res = erts_smp_mtx_trylock(prt->lock);
     if (res == EBUSY) {
 	erts_smp_atomic_dec_nob(&prt->refc);
     }
+#else
+    res = 0;
+#endif
 
     return res;
-#else /* !ERTS_SMP */
-    return 0;
-#endif
 }
 
 ERTS_GLB_INLINE void
 erts_smp_port_lock(Port *prt)
 {
-#ifdef ERTS_SMP
     ASSERT(erts_smp_atomic_read_nob(&prt->refc) > 0);
     erts_smp_atomic_inc_nob(&prt->refc);
+#ifdef ERTS_SMP
     erts_smp_mtx_lock(prt->lock);
 #endif
 }
@@ -1249,14 +1254,14 @@ erts_smp_port_lock(Port *prt)
 ERTS_GLB_INLINE void
 erts_smp_port_unlock(Port *prt)
 {
-#ifdef ERTS_SMP
     erts_aint_t refc;
+#ifdef ERTS_SMP
     erts_smp_mtx_unlock(prt->lock);
+#endif
     refc = erts_smp_atomic_dec_read_nob(&prt->refc);
     ASSERT(refc >= 0);
     if (refc == 0)
 	erts_port_cleanup(prt);
-#endif
 }
 
 #endif /* #if ERTS_GLB_INLINE_INCL_FUNC_DEF */
@@ -1319,12 +1324,12 @@ erts_id2port_sflgs(Eterm id, Process *c_p, ErtsProcLocks c_p_locks, Uint32 sflgs
 	erts_smp_port_state_unlock(prt);
 	prt = NULL;
     }
-#ifdef ERTS_SMP
     else {
 	erts_smp_atomic_inc_nob(&prt->refc);
 	erts_smp_port_state_unlock(prt);
 
-	if (no_proc_locks)
+#ifdef ERTS_SMP
+ 	if (no_proc_locks)
 	    erts_smp_mtx_lock(prt->lock);
 	else if (erts_smp_mtx_trylock(prt->lock) == EBUSY) {
 	    /* Unlock process locks, and acquire locks in lock order... */
@@ -1340,21 +1345,17 @@ erts_id2port_sflgs(Eterm id, Process *c_p, ErtsProcLocks c_p_locks, Uint32 sflgs
 	    erts_smp_port_unlock(prt); /* Also decrements refc... */
 	    prt = NULL;
 	}
-    }
 #endif
 
+    }
+
     return prt;
 }
 
 ERTS_GLB_INLINE void
 erts_port_release(Port *prt)
 {
-#ifdef ERTS_SMP
     erts_smp_port_unlock(prt);
-#else
-    if (prt->status & ERTS_PORT_SFLGS_DEAD)
-	erts_port_cleanup(prt);
-#endif
 }
 
 ERTS_GLB_INLINE Port*
@@ -1935,6 +1936,13 @@ extern erts_driver_t spawn_driver;
 extern erts_driver_t fd_driver;
 
 /* Should maybe be placed in erl_message.h, but then we get an include mess. */
+ERTS_GLB_INLINE Eterm *
+erts_alloc_message_heap_state(Uint size,
+			      ErlHeapFragment **bpp,
+			      ErlOffHeap **ohpp,
+			      Process *receiver,
+			      ErtsProcLocks *receiver_locks,
+			      erts_aint32_t *statep);
 
 ERTS_GLB_INLINE Eterm *
 erts_alloc_message_heap(Uint size,
@@ -1957,16 +1965,22 @@ erts_alloc_message_heap(Uint size,
  */
 
 ERTS_GLB_INLINE Eterm *
-erts_alloc_message_heap(Uint size,
-			ErlHeapFragment **bpp,
-			ErlOffHeap **ohpp,
-			Process *receiver,
-			ErtsProcLocks *receiver_locks)
+erts_alloc_message_heap_state(Uint size,
+			      ErlHeapFragment **bpp,
+			      ErlOffHeap **ohpp,
+			      Process *receiver,
+			      ErtsProcLocks *receiver_locks,
+			      erts_aint32_t *statep)
 {
     Eterm *hp;
+    erts_aint32_t state;
 #ifdef ERTS_SMP
     int locked_main = 0;
-    ErtsProcLocks ulocks = *receiver_locks & ERTS_PROC_LOCKS_MSG_SEND;
+    state = erts_smp_atomic32_read_acqb(&receiver->state);
+    if (statep)
+	*statep = state;
+    if (state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_PENDING_EXIT))
+	goto allocate_in_mbuf;
 #endif
 
     if (size > (Uint) INT_MAX)
@@ -1982,20 +1996,19 @@ erts_alloc_message_heap(Uint size,
 #ifdef ERTS_SMP
     try_allocate_on_heap:
 #endif
-	if (ERTS_PROC_IS_EXITING(receiver)
+	state = erts_smp_atomic32_read_nob(&receiver->state);
+	if (statep)
+	    *statep = state;
+	if ((state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_PENDING_EXIT))
 	    || HEAP_LIMIT(receiver) - HEAP_TOP(receiver) <= size) {
 #ifdef ERTS_SMP
-	    if (locked_main)
-		ulocks |= ERTS_PROC_LOCK_MAIN;
+	    if (locked_main) {
+		*receiver_locks &= ~ERTS_PROC_LOCK_MAIN;
+		erts_smp_proc_unlock(receiver, ERTS_PROC_LOCK_MAIN);
+	    }
 #endif
 	    goto allocate_in_mbuf;
 	}
-#ifdef ERTS_SMP
-	if (ulocks) {
-	    erts_smp_proc_unlock(receiver, ulocks);
-	    *receiver_locks &= ~ulocks;
-	}
-#endif
 	hp = HEAP_TOP(receiver);
 	HEAP_TOP(receiver) = hp + size;
 	*bpp = NULL;
@@ -2011,12 +2024,6 @@ erts_alloc_message_heap(Uint size,
     else {
 	ErlHeapFragment *bp;
     allocate_in_mbuf:
-#ifdef ERTS_SMP
-	if (ulocks) {
-	    *receiver_locks &= ~ulocks;
-	    erts_smp_proc_unlock(receiver, ulocks);
-	}
-#endif
 	bp = new_message_buffer(size);
 	hp = bp->mem;
 	*bpp = bp;
@@ -2026,6 +2033,17 @@ erts_alloc_message_heap(Uint size,
     return hp;
 }
 
+ERTS_GLB_INLINE Eterm *
+erts_alloc_message_heap(Uint size,
+			ErlHeapFragment **bpp,
+			ErlOffHeap **ohpp,
+			Process *receiver,
+			ErtsProcLocks *receiver_locks)
+{
+    return erts_alloc_message_heap_state(size, bpp, ohpp, receiver,
+					 receiver_locks, NULL);
+}
+
 #endif /* #if ERTS_GLB_INLINE_INCL_FUNC_DEF */
 
 #if !HEAP_ON_C_STACK
diff --git a/erts/emulator/beam/io.c b/erts/emulator/beam/io.c
index 8d20178307..4dd60b4d23 100644
--- a/erts/emulator/beam/io.c
+++ b/erts/emulator/beam/io.c
@@ -259,10 +259,8 @@ get_free_port(void)
 	}
     }
     port->status = ERTS_PORT_SFLG_INITIALIZING;
-#ifdef ERTS_SMP
-    ERTS_SMP_LC_ASSERT(erts_smp_atomic_read_nob(&port->refc) == 0);
+    ERTS_LC_ASSERT(erts_smp_atomic_read_nob(&port->refc) == 0);
     erts_smp_atomic_set_nob(&port->refc, 2); /* Port alive + lock */
-#endif	
     erts_smp_port_state_unlock(port);
     return num & port_num_mask;
 }
@@ -340,10 +338,14 @@ port_cleanup(Port *prt)
     prt->drv_ptr = NULL;
     ASSERT(driver);
 
-#ifdef ERTS_SMP
-
     ASSERT(prt->status & ERTS_PORT_SFLG_FREE_SCHEDULED);
-    ERTS_SMP_LC_ASSERT(erts_smp_atomic_read_nob(&prt->refc) == 0);
+    ERTS_LC_ASSERT(erts_smp_atomic_read_nob(&prt->refc) == 0);
+
+    ASSERT(prt->status & ERTS_PORT_SFLG_PORT_DEBUG);
+    ASSERT(!(prt->status & ERTS_PORT_SFLG_FREE));
+    prt->status = ERTS_PORT_SFLG_FREE;
+
+#ifdef ERTS_SMP
 
     port_specific = (prt->status & ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK);
 
@@ -352,10 +354,6 @@ port_cleanup(Port *prt)
 
     prt->lock = NULL;
 
-    ASSERT(prt->status & ERTS_PORT_SFLG_PORT_DEBUG);
-    ASSERT(!(prt->status & ERTS_PORT_SFLG_FREE));
-    prt->status = ERTS_PORT_SFLG_FREE;
-
     erts_smp_port_state_unlock(prt);    
     erts_smp_mtx_unlock(mtx);
 
@@ -605,10 +603,8 @@ erts_open_driver(erts_driver_t* driver,	/* Pointer to driver. */
 	/* Need to mark the port as free again */
 	erts_smp_port_state_lock(port);
 	port->status = ERTS_PORT_SFLG_FREE;
-#ifdef ERTS_SMP
-	ERTS_SMP_LC_ASSERT(erts_smp_atomic_read_nob(&port->refc) == 2);
+	ERTS_LC_ASSERT(erts_smp_atomic_read_nob(&port->refc) == 2);
 	erts_smp_atomic_set_nob(&port->refc, 0); 
-#endif	
 	erts_smp_port_state_unlock(port);
 	return -3;
     }
@@ -1343,8 +1339,8 @@ void init_io(void)
 
     for (i = 0; i < erts_max_ports; i++) {
 	erts_port_task_init_sched(&erts_port[i].sched);
-#ifdef ERTS_SMP
 	erts_smp_atomic_init_nob(&erts_port[i].refc, 0);
+#ifdef ERTS_SMP
 	erts_port[i].lock = NULL;
 	erts_port[i].xports = NULL;
 	erts_smp_spinlock_init_x(&erts_port[i].state_lck, "port_state", make_small(i));
diff --git a/erts/emulator/beam/register.c b/erts/emulator/beam/register.c
index 0ddae56322..c02872ef80 100644
--- a/erts/emulator/beam/register.c
+++ b/erts/emulator/beam/register.c
@@ -93,14 +93,14 @@ reg_safe_write_lock(Process *c_p, ErtsProcLocks *c_p_locks)
     reg_write_lock();
 }
 
+#endif
+
 static ERTS_INLINE int
 is_proc_alive(Process *p)
 {
     return !ERTS_PROC_IS_EXITING(p);
 }
 
-#endif
-
 void register_info(int to, void *to_arg)
 {
     int lock = !ERTS_IS_CRASH_DUMPING;
@@ -384,8 +384,7 @@ erts_whereis_name(Process *c_p,
 	    }
 #else
 	    if (rp->p
-		&& ((flags & ERTS_P2P_FLG_ALLOW_OTHER_X)
-		    || rp->p->status != P_EXITING))
+		&& ((flags & ERTS_P2P_FLG_ALLOW_OTHER_X) || is_proc_alive(rp->p)))
 		*proc = rp->p;
 	    else
 		*proc = NULL;
@@ -397,7 +396,9 @@ erts_whereis_name(Process *c_p,
 	if (!rp || !rp->pt)
 	    *port = NULL;
 	else {
-#ifdef ERTS_SMP
+#ifndef ERTS_SMP
+	    erts_smp_atomic_inc_nob(&rp->pt->refc);
+#else
 	    if (pending_port == rp->pt)
 		pending_port = NULL;
 	    else {
@@ -504,9 +505,11 @@ int erts_unregister_name(Process *c_p,
     if ((rp = (RegProc*) hash_get(&process_reg, (void*) &r)) != NULL) {
 	if (rp->pt) {
 	    if (port != rp->pt) {
-#ifdef ERTS_SMP
+#ifndef ERTS_SMP
+		erts_smp_atomic_inc_nob(&rp->pt->refc);
+#else
 		if (port) {
-		    ERTS_SMP_LC_ASSERT(port != c_prt);
+		    ASSERT(port != c_prt);
 		    erts_smp_port_unlock(port);
 		    port = NULL;
 		}
diff --git a/erts/emulator/beam/utils.c b/erts/emulator/beam/utils.c
index 245916bc0d..db6597dc7c 100644
--- a/erts/emulator/beam/utils.c
+++ b/erts/emulator/beam/utils.c
@@ -1666,12 +1666,20 @@ static int do_send_to_logger(Eterm tag, Eterm gleader, char *buf, int len)
     }
 
 #ifndef ERTS_SMP
-    if (
 #ifdef USE_THREADS
-	!erts_get_scheduler_data() || /* Must be scheduler thread */
+    p = NULL;
+    if (erts_get_scheduler_data()) /* Must be scheduler thread */
 #endif
-	(p = erts_whereis_process(NULL, 0, am_error_logger, 0, 0)) == NULL
-	|| p->status == P_RUNNING) {
+    {
+	p = erts_whereis_process(NULL, 0, am_error_logger, 0, 0);
+	if (p) {
+	    erts_aint32_t state = erts_smp_atomic32_read_acqb(&p->state);
+	    if (state & ERTS_PSFLG_RUNNING)
+		p = NULL;
+	}
+    }
+
+    if (!p) {
 	/* buf *always* points to a null terminated string */
 	erts_fprintf(stderr, "(no error logger present) %T: \"%s\"\n",
 		     tag, buf);