Use new atomic API in runtime system

All uses of the old deprecated atomic API in the runtime system
have been replaced with the use of the new atomic API. In a lot of
places this change imply a relaxation of memory barriers used.

1 files changed, 130 insertions, 127 deletions

diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 2704359a8f..bbdcf79d00 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -134,15 +134,15 @@ int erts_disable_proc_not_running_opt;
 #ifndef DEBUG
 
 #define ERTS_SCHDLR_SSPND_CHNG_SET(VAL, OLD_VAL) \
-  erts_smp_atomic32_set(&schdlr_sspnd.changing, (VAL))
+  erts_smp_atomic32_set_nob(&schdlr_sspnd.changing, (VAL))
 
 #else
 
 #define ERTS_SCHDLR_SSPND_CHNG_SET(VAL, OLD_VAL)			\
 do {									\
     erts_aint32_t old_val__;						\
-    old_val__ = erts_smp_atomic32_xchg(&schdlr_sspnd.changing,		\
-				       (VAL));				\
+    old_val__ = erts_smp_atomic32_xchg_nob(&schdlr_sspnd.changing,     	\
+					   (VAL));			\
     ASSERT(old_val__ == (OLD_VAL));					\
 } while (0)
 
@@ -158,7 +158,7 @@ static struct {
     erts_smp_atomic32_t changing;
     erts_smp_atomic32_t active;
     struct {
-	erts_smp_atomic32_t ongoing;
+	int ongoing;
 	long wait_active;
 	ErtsProcList *procs;
     } msb; /* Multi Scheduling Block */
@@ -410,7 +410,7 @@ erts_init_process(int ncpu)
 
     init_proclist_alloc();
 
-    erts_smp_atomic32_init(&process_count, 0);
+    erts_smp_atomic32_init_nob(&process_count, 0);
 
     if (erts_use_r9_pids_ports) {
 	proc_bits = ERTS_R9_PROC_BITS;
@@ -694,8 +694,8 @@ erts_smp_schedule_misc_aux_work(int ignore_self,
 	erts_smp_mtx_unlock(&misc_aux_work_queues[ix].data.mtx);
 
 	ssi = ERTS_SCHED_SLEEP_INFO_IX(ix);
-	aux_work = erts_smp_atomic32_bor(&ssi->aux_work,
-					 ERTS_SSI_AUX_WORK_MISC);
+	aux_work = erts_smp_atomic32_read_bor_nob(&ssi->aux_work,
+						  ERTS_SSI_AUX_WORK_MISC);
 	if ((aux_work & ERTS_SSI_AUX_WORK_MISC) == 0)
 	    erts_sched_poke(ssi);
    }
@@ -711,8 +711,8 @@ erts_smp_notify_check_children_needed(void)
 	erts_aint32_t aux_work;
 	ErtsSchedulerSleepInfo *ssi;
 	ssi = ERTS_SCHED_SLEEP_INFO_IX(i);
-	aux_work = erts_smp_atomic32_bor(&ssi->aux_work,
-					 ERTS_SSI_AUX_WORK_CHECK_CHILDREN);
+	aux_work = erts_smp_atomic32_read_bor_nob(&ssi->aux_work,
+						  ERTS_SSI_AUX_WORK_CHECK_CHILDREN);
 	if (!(aux_work & ERTS_SSI_AUX_WORK_CHECK_CHILDREN))
 	    erts_sched_poke(ssi);
     }
@@ -727,15 +727,15 @@ blockable_aux_work(ErtsSchedulerData *esdp,
 {
     if (aux_work & ERTS_SSI_BLOCKABLE_AUX_WORK_MASK) {
 	if (aux_work & ERTS_SSI_AUX_WORK_MISC) {
-	    aux_work = erts_smp_atomic32_band(&ssi->aux_work,
-					      ~ERTS_SSI_AUX_WORK_MISC);
+	    aux_work = erts_smp_atomic32_read_band_nob(&ssi->aux_work,
+						       ~ERTS_SSI_AUX_WORK_MISC);
 	    aux_work &= ~ERTS_SSI_AUX_WORK_MISC;
 	    handle_misc_aux_work(esdp);
 	}
 #ifdef ERTS_SMP_SCHEDULERS_NEED_TO_CHECK_CHILDREN
 	if (aux_work & ERTS_SSI_AUX_WORK_CHECK_CHILDREN) {
-	    aux_work = erts_smp_atomic32_band(&ssi->aux_work,
-					      ~ERTS_SSI_AUX_WORK_CHECK_CHILDREN);
+	    aux_work = erts_smp_atomic32_band_nob(&ssi->aux_work,
+						  ~ERTS_SSI_AUX_WORK_CHECK_CHILDREN);
 	    aux_work &= ~ERTS_SSI_AUX_WORK_CHECK_CHILDREN;
 	    erts_check_children();
 	}
@@ -815,7 +815,7 @@ erts_active_schedulers(void)
 static ERTS_INLINE void
 clear_sys_scheduling(void)
 {
-    erts_smp_atomic32_set_relb(&doing_sys_schedule, 0);
+    erts_smp_atomic32_set_mb(&doing_sys_schedule, 0);
 }
 
 static ERTS_INLINE int
@@ -882,42 +882,43 @@ sched_active(Uint no, ErtsRunQueue *rq)
 static int ERTS_INLINE
 ongoing_multi_scheduling_block(void)
 {
-    return erts_smp_atomic32_read(&schdlr_sspnd.msb.ongoing) != 0;
+    ERTS_SMP_LC_ASSERT(erts_lc_mtx_is_locked(&schdlr_sspnd.mtx));
+    return schdlr_sspnd.msb.ongoing;
 }
 
 static ERTS_INLINE void
 empty_runq(ErtsRunQueue *rq)
 {
-    erts_aint32_t oifls = erts_smp_atomic32_band(&rq->info_flags,
-						 ~ERTS_RUNQ_IFLG_NONEMPTY);
+    erts_aint32_t oifls = erts_smp_atomic32_read_band_nob(&rq->info_flags,
+							  ~ERTS_RUNQ_IFLG_NONEMPTY);
     if (oifls & ERTS_RUNQ_IFLG_NONEMPTY) {
 #ifdef DEBUG
-	erts_aint32_t empty = erts_smp_atomic32_read(&no_empty_run_queues);
+	erts_aint32_t empty = erts_smp_atomic32_read_nob(&no_empty_run_queues);
 	/*
 	 * For a short period of time no_empty_run_queues may have
 	 * been increased twice for a specific run queue.
 	 */
 	ASSERT(0 <= empty && empty < 2*erts_no_run_queues);
 #endif
-	erts_smp_atomic32_inc(&no_empty_run_queues);
+	erts_smp_atomic32_inc_relb(&no_empty_run_queues);
     }
 }
 
 static ERTS_INLINE void
 non_empty_runq(ErtsRunQueue *rq)
 {
-    erts_aint32_t oifls = erts_smp_atomic32_bor(&rq->info_flags,
-						ERTS_RUNQ_IFLG_NONEMPTY);
+    erts_aint32_t oifls = erts_smp_atomic32_read_bor_nob(&rq->info_flags,
+							 ERTS_RUNQ_IFLG_NONEMPTY);
     if (!(oifls & ERTS_RUNQ_IFLG_NONEMPTY)) {
 #ifdef DEBUG
-	erts_aint32_t empty = erts_smp_atomic32_read(&no_empty_run_queues);
+	erts_aint32_t empty = erts_smp_atomic32_read_nob(&no_empty_run_queues);
 	/*
 	 * For a short period of time no_empty_run_queues may have
 	 * been increased twice for a specific run queue.
 	 */
 	ASSERT(0 < empty && empty <= 2*erts_no_run_queues);
 #endif
-	erts_smp_atomic32_dec(&no_empty_run_queues);
+	erts_smp_atomic32_dec_relb(&no_empty_run_queues);
     }
 }
 
@@ -930,7 +931,7 @@ sched_prep_spin_wait(ErtsSchedulerSleepInfo *ssi)
     erts_aint32_t xflgs = 0;
 
     do {
-	oflgs = erts_smp_atomic32_cmpxchg(&ssi->flags, nflgs, xflgs);
+	oflgs = erts_smp_atomic32_cmpxchg_acqb(&ssi->flags, nflgs, xflgs);
 	if (oflgs == xflgs)
 	    return nflgs;
 	xflgs = oflgs;
@@ -947,7 +948,7 @@ sched_prep_cont_spin_wait(ErtsSchedulerSleepInfo *ssi)
     erts_aint32_t xflgs = ERTS_SSI_FLG_WAITING;
 
     do {
-	oflgs = erts_smp_atomic32_cmpxchg(&ssi->flags, nflgs, xflgs);
+	oflgs = erts_smp_atomic32_cmpxchg_acqb(&ssi->flags, nflgs, xflgs);
 	if (oflgs == xflgs)
 	    return nflgs;
 	xflgs = oflgs;
@@ -989,7 +990,7 @@ sched_set_sleeptype(ErtsSchedulerSleepInfo *ssi, erts_aint32_t sleep_type)
 	erts_tse_reset(ssi->event);
 
     while (1) {
-	oflgs = erts_smp_atomic32_cmpxchg(&ssi->flags, nflgs, xflgs);
+	oflgs = erts_smp_atomic32_cmpxchg_acqb(&ssi->flags, nflgs, xflgs);
 	if (oflgs == xflgs)
 	    return nflgs;
 	if ((oflgs & (ERTS_SSI_FLG_SLEEPING|ERTS_SSI_FLG_WAITING))
@@ -1049,7 +1050,7 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
     tse_wait:
 
 #ifdef ERTS_SCHED_NEED_BLOCKABLE_AUX_WORK
-	aux_work = erts_smp_atomic32_read(&ssi->aux_work);
+	aux_work = erts_smp_atomic32_read_nob(&ssi->aux_work);
     tse_blockable_aux_work:
 	aux_work = blockable_aux_work(esdp, ssi, aux_work);
 #endif
@@ -1059,7 +1060,7 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
 
 #ifdef ERTS_SCHED_NEED_NONBLOCKABLE_AUX_WORK
 #ifndef ERTS_SCHED_NEED_BLOCKABLE_AUX_WORK
-	    aux_work = erts_smp_atomic32_read(&ssi->aux_work);
+	    aux_work = erts_smp_atomic32_read_nob(&ssi->aux_work);
 #endif
 	    nonblockable_aux_work(esdp, ssi, aux_work);
 #endif
@@ -1092,7 +1093,7 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
 	    }
 
 #ifdef ERTS_SCHED_NEED_BLOCKABLE_AUX_WORK
-	    aux_work = erts_smp_atomic32_read(&ssi->aux_work);
+	    aux_work = erts_smp_atomic32_read_nob(&ssi->aux_work);
 	    if (aux_work & ERTS_SSI_BLOCKABLE_AUX_WORK_MASK) {
 		erts_smp_activity_end(ERTS_ACTIVITY_WAIT, NULL, NULL, NULL);
 		goto tse_blockable_aux_work;
@@ -1104,7 +1105,7 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
 	erts_smp_activity_end(ERTS_ACTIVITY_WAIT, NULL, NULL, NULL);
 
 	if (flgs & ~ERTS_SSI_FLG_SUSPENDED)
-	    erts_smp_atomic32_band(&ssi->flags, ERTS_SSI_FLG_SUSPENDED);
+	    erts_smp_atomic32_read_band_nob(&ssi->flags, ERTS_SSI_FLG_SUSPENDED);
 
 	erts_smp_runq_lock(rq);
 	sched_active(esdp->no, rq);
@@ -1136,12 +1137,12 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
 	sys_aux_work:
 
 #ifdef ERTS_SCHED_NEED_BLOCKABLE_AUX_WORK
-	    aux_work = erts_smp_atomic32_read(&ssi->aux_work);
+	    aux_work = erts_smp_atomic32_read_nob(&ssi->aux_work);
 	    aux_work = blockable_aux_work(esdp, ssi, aux_work);
 #endif
 #ifdef ERTS_SCHED_NEED_NONBLOCKABLE_AUX_WORK
 #ifndef ERTS_SCHED_NEED_BLOCKABLE_AUX_WORK
-	    aux_work = erts_smp_atomic32_read(&ssi->aux_work);
+	    aux_work = erts_smp_atomic32_read_nob(&ssi->aux_work);
 #endif
 	    nonblockable_aux_work(esdp, ssi, aux_work);
 #endif
@@ -1239,7 +1240,7 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
 	sys_locked_woken:
 	    clear_sys_scheduling();
 	    if (flgs & ~ERTS_SSI_FLG_SUSPENDED)
-		erts_smp_atomic32_band(&ssi->flags, ERTS_SSI_FLG_SUSPENDED);
+		erts_smp_atomic32_read_band_nob(&ssi->flags, ERTS_SSI_FLG_SUSPENDED);
 	    sched_active_sys(esdp->no, rq);
 	}
     }
@@ -1255,7 +1256,7 @@ ssi_flags_set_wake(ErtsSchedulerSleepInfo *ssi)
     erts_aint32_t nflgs = 0;
     erts_aint32_t xflgs = ERTS_SSI_FLG_SLEEPING|ERTS_SSI_FLG_WAITING;
     while (1) {
-	oflgs = erts_smp_atomic32_cmpxchg(&ssi->flags, nflgs, xflgs);
+	oflgs = erts_smp_atomic32_cmpxchg_relb(&ssi->flags, nflgs, xflgs);
 	if (oflgs == xflgs)
 	    return oflgs;
 	nflgs = oflgs & ERTS_SSI_FLG_SUSPENDED;
@@ -1298,7 +1299,6 @@ wake_scheduler(ErtsRunQueue *rq, int incq, int one)
 
 	erts_smp_spin_unlock(&sl->lock);
 
-	ERTS_THR_MEMORY_BARRIER;
 	flgs = ssi_flags_set_wake(ssi);
 	erts_sched_finish_poke(ssi, flgs);
 
@@ -1344,13 +1344,13 @@ init_no_runqs(int active, int used)
 {
     erts_aint32_t no_runqs = (erts_aint32_t) (active & ERTS_NO_RUNQS_MASK);
     no_runqs |= (erts_aint32_t) ((used & ERTS_NO_RUNQS_MASK) << ERTS_NO_USED_RUNQS_SHIFT);
-    erts_smp_atomic32_init(&balance_info.no_runqs, no_runqs);
+    erts_smp_atomic32_init_nob(&balance_info.no_runqs, no_runqs);
 }
 
 static ERTS_INLINE void
 get_no_runqs(int *active, int *used)
 {
-    erts_aint32_t no_runqs = erts_smp_atomic32_read(&balance_info.no_runqs);
+    erts_aint32_t no_runqs = erts_smp_atomic32_read_nob(&balance_info.no_runqs);
     if (active)
 	*active = (int) (no_runqs & ERTS_NO_RUNQS_MASK);
     if (used)
@@ -1360,11 +1360,12 @@ get_no_runqs(int *active, int *used)
 static ERTS_INLINE void
 set_no_used_runqs(int used)
 {
-    erts_aint32_t exp = erts_smp_atomic32_read(&balance_info.no_runqs);
+    erts_aint32_t exp = erts_smp_atomic32_read_nob(&balance_info.no_runqs);
     while (1) {
 	erts_aint32_t act, new;
-	new = (used << ERTS_NO_USED_RUNQS_SHIFT) | (exp & ERTS_NO_RUNQS_MASK);
-	act = erts_smp_atomic32_cmpxchg(&balance_info.no_runqs, new, exp);
+	new = (used & ERTS_NO_RUNQS_MASK) << ERTS_NO_USED_RUNQS_SHIFT;
+	new |= exp & ERTS_NO_RUNQS_MASK;
+	act = erts_smp_atomic32_cmpxchg_nob(&balance_info.no_runqs, new, exp);
 	if (act == exp)
 	    break;
 	exp = act;
@@ -1374,11 +1375,12 @@ set_no_used_runqs(int used)
 static ERTS_INLINE void
 set_no_active_runqs(int active)
 {
-    erts_aint32_t exp = erts_smp_atomic32_read(&balance_info.no_runqs);
+    erts_aint32_t exp = erts_smp_atomic32_read_nob(&balance_info.no_runqs);
     while (1) {
 	erts_aint32_t act, new;
-	new = (exp & (ERTS_NO_RUNQS_MASK << ERTS_NO_USED_RUNQS_SHIFT)) | active;
-	act = erts_smp_atomic32_cmpxchg(&balance_info.no_runqs, new, exp);
+	new = exp & (ERTS_NO_RUNQS_MASK << ERTS_NO_USED_RUNQS_SHIFT);
+	new |= active & ERTS_NO_RUNQS_MASK;
+	act = erts_smp_atomic32_cmpxchg_nob(&balance_info.no_runqs, new, exp);
 	if (act == exp)
 	    break;
 	exp = act;
@@ -1388,13 +1390,14 @@ set_no_active_runqs(int active)
 static ERTS_INLINE int
 try_inc_no_active_runqs(int active)
 {
-    erts_aint32_t exp = erts_smp_atomic32_read(&balance_info.no_runqs);
+    erts_aint32_t exp = erts_smp_atomic32_read_nob(&balance_info.no_runqs);
     if (((exp >> ERTS_NO_USED_RUNQS_SHIFT) & ERTS_NO_RUNQS_MASK) < active)
 	return 0;
     if ((exp & ERTS_NO_RUNQS_MASK) + 1 == active) {
 	erts_aint32_t new, act;
-	new = (exp & ~ERTS_NO_RUNQS_MASK) | active;
-	act = erts_smp_atomic32_cmpxchg(&balance_info.no_runqs, new, exp);
+	new = exp & (ERTS_NO_RUNQS_MASK << ERTS_NO_USED_RUNQS_SHIFT);
+	new |= active & ERTS_NO_RUNQS_MASK;
+	act = erts_smp_atomic32_cmpxchg_nob(&balance_info.no_runqs, new, exp);
 	if (act == exp)
 	    return 1;
     }
@@ -1410,7 +1413,7 @@ chk_wake_sched(ErtsRunQueue *crq, int ix, int activate)
     if (crq->ix == ix)
 	return 0;
     wrq = ERTS_RUNQ_IX(ix);
-    iflgs = erts_smp_atomic32_read(&wrq->info_flags);
+    iflgs = erts_smp_atomic32_read_nob(&wrq->info_flags);
     if (!(iflgs & (ERTS_RUNQ_IFLG_SUSPENDED|ERTS_RUNQ_IFLG_NONEMPTY))) {
 	if (activate) {
 	    if (try_inc_no_active_runqs(ix+1)) {
@@ -1652,15 +1655,15 @@ evacuate_run_queue(ErtsRunQueue *evac_rq, ErtsRunQueue *rq)
 
     erts_smp_runq_lock(evac_rq);
 
-    erts_smp_atomic32_bor(&evac_rq->scheduler->ssi->flags,
-			  ERTS_SSI_FLG_SUSPENDED);
+    erts_smp_atomic32_read_bor_nob(&evac_rq->scheduler->ssi->flags,
+				   ERTS_SSI_FLG_SUSPENDED);
 
     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_smp_atomic32_bor(&evac_rq->info_flags, ERTS_RUNQ_IFLG_SUSPENDED);
+    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
@@ -1909,7 +1912,7 @@ 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(&vrq->info_flags);
+    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);
     else
@@ -2061,7 +2064,7 @@ check_balance(ErtsRunQueue *c_rq)
     int forced, active, current_active, oowc, half_full_scheds, full_scheds,
 	mmax_len, blnc_no_rqs, qix, pix, freds_hist_ix;
 
-    if (erts_smp_atomic32_xchg(&balance_info.checking_balance, 1)) {
+    if (erts_smp_atomic32_xchg_nob(&balance_info.checking_balance, 1)) {
 	c_rq->check_balance_reds = INT_MAX;
 	return;
     }
@@ -2069,7 +2072,7 @@ check_balance(ErtsRunQueue *c_rq)
     get_no_runqs(NULL, &blnc_no_rqs);
     if (blnc_no_rqs == 1) {
 	c_rq->check_balance_reds = INT_MAX;
-	erts_smp_atomic32_set(&balance_info.checking_balance, 0);
+	erts_smp_atomic32_set_nob(&balance_info.checking_balance, 0);
 	return;
     }
 
@@ -2077,7 +2080,7 @@ check_balance(ErtsRunQueue *c_rq)
 
     if (balance_info.halftime) {	
 	balance_info.halftime = 0;
-	erts_smp_atomic32_set(&balance_info.checking_balance, 0);
+	erts_smp_atomic32_set_nob(&balance_info.checking_balance, 0);
 	ERTS_FOREACH_RUNQ(rq,
 	{
 	    if (rq->waiting)
@@ -2111,7 +2114,7 @@ check_balance(ErtsRunQueue *c_rq)
 	erts_smp_mtx_unlock(&balance_info.update_mtx);
 	erts_smp_runq_lock(c_rq);
 	c_rq->check_balance_reds = INT_MAX;
-	erts_smp_atomic32_set(&balance_info.checking_balance, 0);
+	erts_smp_atomic32_set_nob(&balance_info.checking_balance, 0);
 	return;
     }
 
@@ -2456,7 +2459,7 @@ erts_fprintf(stderr, "--------------------------------\n");
     set_no_active_runqs(active);
 
     balance_info.halftime = 1;
-    erts_smp_atomic32_set(&balance_info.checking_balance, 0);
+    erts_smp_atomic32_set_nob(&balance_info.checking_balance, 0);
 
     /* Write migration paths and reset balance statistics in all queues */
     for (qix = 0; qix < blnc_no_rqs; qix++) {
@@ -2598,7 +2601,7 @@ erts_init_scheduling(int mrq, int no_schedulers, int no_schedulers_online)
 	erts_alloc_permanent_cache_aligned(ERTS_ALC_T_RUNQS,
 					   sizeof(ErtsAlignedRunQueue) * n);
 #ifdef ERTS_SMP
-    erts_smp_atomic32_init(&no_empty_run_queues, 0);
+    erts_smp_atomic32_init_nob(&no_empty_run_queues, 0);
 #endif
 
     erts_no_run_queues = n;
@@ -2608,7 +2611,7 @@ erts_init_scheduling(int mrq, int no_schedulers, int no_schedulers_online)
 	ErtsRunQueue *rq = ERTS_RUNQ_IX(ix);
 
 	rq->ix = ix;
-	erts_smp_atomic32_init(&rq->info_flags, ERTS_RUNQ_IFLG_NONEMPTY);
+	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.
@@ -2701,9 +2704,9 @@ erts_init_scheduling(int mrq, int no_schedulers, int no_schedulers_online)
 	ssi->next = NULL;
 	ssi->prev = NULL;
 #endif
-	erts_smp_atomic32_init(&ssi->flags, 0);
+	erts_smp_atomic32_init_nob(&ssi->flags, 0);
 	ssi->event = NULL; /* initialized in sched_thread_func */
-	erts_smp_atomic32_init(&ssi->aux_work, 0);
+	erts_smp_atomic32_init_nob(&ssi->aux_work, 0);
     }
 #endif
 
@@ -2747,7 +2750,7 @@ erts_init_scheduling(int mrq, int no_schedulers, int no_schedulers_online)
 	}
 
 #ifdef ERTS_SMP
-	erts_smp_atomic32_init(&esdp->chk_cpu_bind, 0);
+	erts_smp_atomic32_init_nob(&esdp->chk_cpu_bind, 0);
 #endif
     }
 
@@ -2755,11 +2758,11 @@ erts_init_scheduling(int mrq, int no_schedulers, int no_schedulers_online)
     erts_smp_mtx_init(&schdlr_sspnd.mtx, "schdlr_sspnd");
     erts_smp_cnd_init(&schdlr_sspnd.cnd);
 
-    erts_smp_atomic32_init(&schdlr_sspnd.changing, 0);
+    erts_smp_atomic32_init_nob(&schdlr_sspnd.changing, 0);
     schdlr_sspnd.online = no_schedulers_online;
     schdlr_sspnd.curr_online = no_schedulers;
-    erts_smp_atomic32_init(&schdlr_sspnd.msb.ongoing, 0);
-    erts_smp_atomic32_init(&schdlr_sspnd.active, no_schedulers);
+    schdlr_sspnd.msb.ongoing = 0;
+    erts_smp_atomic32_init_nob(&schdlr_sspnd.active, no_schedulers);
     schdlr_sspnd.msb.procs = NULL;
     init_no_runqs(no_schedulers,
 		  erts_common_run_queue ? 1 : no_schedulers_online);
@@ -2768,7 +2771,7 @@ erts_init_scheduling(int mrq, int no_schedulers, int no_schedulers_online)
     balance_info.forced_check_balance = 0;
     balance_info.halftime = 1;
     balance_info.full_reds_history_index = 0;
-    erts_smp_atomic32_init(&balance_info.checking_balance, 0);
+    erts_smp_atomic32_init_nob(&balance_info.checking_balance, 0);
     balance_info.prev_rise.active_runqs = 0;
     balance_info.prev_rise.max_len = 0;
     balance_info.prev_rise.reds = 0;
@@ -2777,8 +2780,8 @@ erts_init_scheduling(int mrq, int no_schedulers, int no_schedulers_online)
     if (no_schedulers_online < no_schedulers) {
 	if (erts_common_run_queue) {
 	    for (ix = no_schedulers_online; ix < no_schedulers; ix++)
-		erts_smp_atomic32_bor(&ERTS_SCHED_SLEEP_INFO_IX(ix)->flags,
-				      ERTS_SSI_FLG_SUSPENDED);
+		erts_smp_atomic32_read_bor_nob(&ERTS_SCHED_SLEEP_INFO_IX(ix)->flags,
+					       ERTS_SSI_FLG_SUSPENDED);
 	}
 	else {
 	    for (ix = no_schedulers_online; ix < erts_no_run_queues; ix++)
@@ -2792,7 +2795,7 @@ erts_init_scheduling(int mrq, int no_schedulers, int no_schedulers_online)
     ERTS_SCHDLR_SSPND_CHNG_SET((ERTS_SCHDLR_SSPND_CHNG_ONLN
 				| ERTS_SCHDLR_SSPND_CHNG_WAITER), 0);
 
-    erts_smp_atomic32_init(&doing_sys_schedule, 0);
+    erts_smp_atomic32_init_nob(&doing_sys_schedule, 0);
 
     init_misc_aux_work();
 
@@ -2808,7 +2811,7 @@ erts_init_scheduling(int mrq, int no_schedulers, int no_schedulers_online)
     erts_no_schedulers = 1;
 #endif
 
-    erts_smp_atomic32_init(&function_calls, 0);
+    erts_smp_atomic32_init_nob(&function_calls, 0);
 
     /* init port tasks */
     erts_port_task_init();
@@ -2935,10 +2938,10 @@ int
 erts_get_max_no_executing_schedulers(void)
 {
 #ifdef ERTS_SMP
-    if (erts_smp_atomic32_read(&schdlr_sspnd.changing))
+    if (erts_smp_atomic32_read_nob(&schdlr_sspnd.changing))
 	return (int) erts_no_schedulers;
     ERTS_THR_MEMORY_BARRIER;
-    return (int) erts_smp_atomic32_read(&schdlr_sspnd.active);
+    return (int) erts_smp_atomic32_read_nob(&schdlr_sspnd.active);
 #else
     return 1;
 #endif
@@ -2968,7 +2971,7 @@ scheduler_ix_resume_wake(Uint ix)
 			   | ERTS_SSI_FLG_SUSPENDED);
     erts_aint32_t oflgs;
     do {
-	oflgs = erts_smp_atomic32_cmpxchg(&ssi->flags, 0, xflgs);
+	oflgs = erts_smp_atomic32_cmpxchg_relb(&ssi->flags, 0, xflgs);
 	if (oflgs == xflgs) {
 	    erts_sched_finish_poke(ssi, oflgs);
 	    break;
@@ -2987,7 +2990,7 @@ sched_prep_spin_suspended(ErtsSchedulerSleepInfo *ssi, erts_aint32_t xpct)
     erts_aint32_t xflgs = xpct;
 
     do {
-	oflgs = erts_smp_atomic32_cmpxchg(&ssi->flags, nflgs, xflgs);
+	oflgs = erts_smp_atomic32_cmpxchg_acqb(&ssi->flags, nflgs, xflgs);
 	if (oflgs == xflgs)
 	    return nflgs;
 	xflgs = oflgs;
@@ -3037,7 +3040,7 @@ sched_set_suspended_sleeptype(ErtsSchedulerSleepInfo *ssi)
     erts_tse_reset(ssi->event);
 
     while (1) {
-	oflgs = erts_smp_atomic32_cmpxchg(&ssi->flags, nflgs, xflgs);
+	oflgs = erts_smp_atomic32_cmpxchg_acqb(&ssi->flags, nflgs, xflgs);
 	if (oflgs == xflgs)
 	    return nflgs;
 	if ((oflgs & (ERTS_SSI_FLG_SLEEPING
@@ -3092,15 +3095,15 @@ suspend_scheduler(ErtsSchedulerData *esdp)
     flgs = sched_prep_spin_suspended(ssi, ERTS_SSI_FLG_SUSPENDED);
     if (flgs & ERTS_SSI_FLG_SUSPENDED) {
 
-	active_schedulers = erts_smp_atomic32_dectest(&schdlr_sspnd.active);
+	active_schedulers = erts_smp_atomic32_dec_read_nob(&schdlr_sspnd.active);
 	ASSERT(active_schedulers >= 1);
-	changing = erts_smp_atomic32_read(&schdlr_sspnd.changing);
+	changing = erts_smp_atomic32_read_nob(&schdlr_sspnd.changing);
 	if (changing & ERTS_SCHDLR_SSPND_CHNG_MSB) {
 	    if (active_schedulers == schdlr_sspnd.msb.wait_active)
 		wake = 1;
 	    if (active_schedulers == 1) {
-		changing = erts_smp_atomic32_band(&schdlr_sspnd.changing,
-						  ~ERTS_SCHDLR_SSPND_CHNG_MSB);
+		changing = erts_smp_atomic32_read_band_nob(&schdlr_sspnd.changing,
+							   ~ERTS_SCHDLR_SSPND_CHNG_MSB);
 		changing &= ~ERTS_SCHDLR_SSPND_CHNG_MSB;
 	    }
 	}
@@ -3122,8 +3125,8 @@ suspend_scheduler(ErtsSchedulerData *esdp)
 		    && schdlr_sspnd.curr_online == schdlr_sspnd.wait_curr_online)
 		    wake = 1;
 		if (schdlr_sspnd.online == schdlr_sspnd.curr_online) {
-		    changing = erts_smp_atomic32_band(&schdlr_sspnd.changing,
-						      ~ERTS_SCHDLR_SSPND_CHNG_ONLN);
+		    changing = erts_smp_atomic32_read_band_nob(&schdlr_sspnd.changing,
+							       ~ERTS_SCHDLR_SSPND_CHNG_ONLN);
 		    changing &= ~ERTS_SCHDLR_SSPND_CHNG_ONLN;
 		}
 	    }
@@ -3140,7 +3143,7 @@ suspend_scheduler(ErtsSchedulerData *esdp)
 
 
 #ifdef ERTS_SCHED_NEED_BLOCKABLE_AUX_WORK
-	    aux_work = erts_smp_atomic32_read(&ssi->aux_work);
+	    aux_work = erts_smp_atomic32_read_nob(&ssi->aux_work);
 	blockable_aux_work:
 	    blockable_aux_work(esdp, ssi, aux_work);
 #endif
@@ -3176,13 +3179,13 @@ suspend_scheduler(ErtsSchedulerData *esdp)
 						       | ERTS_SSI_FLG_SUSPENDED));
 		if (!(flgs & ERTS_SSI_FLG_SUSPENDED))
 		    break;
-		changing = erts_smp_atomic32_read(&schdlr_sspnd.changing);
+		changing = erts_smp_atomic32_read_nob(&schdlr_sspnd.changing);
 		if (changing & ~ERTS_SCHDLR_SSPND_CHNG_WAITER)
 		    break;
 
 
 #ifdef ERTS_SCHED_NEED_BLOCKABLE_AUX_WORK
-		aux_work = erts_smp_atomic32_read(&ssi->aux_work);
+		aux_work = erts_smp_atomic32_read_nob(&ssi->aux_work);
 		if (aux_work & ERTS_SSI_BLOCKABLE_AUX_WORK_MASK) {
 		    erts_smp_activity_end(ERTS_ACTIVITY_WAIT, NULL, NULL, NULL);
 		    goto blockable_aux_work;
@@ -3194,19 +3197,19 @@ suspend_scheduler(ErtsSchedulerData *esdp)
 	    erts_smp_activity_end(ERTS_ACTIVITY_WAIT, NULL, NULL, NULL);
 
 	    erts_smp_mtx_lock(&schdlr_sspnd.mtx);
-	    changing = erts_smp_atomic32_read(&schdlr_sspnd.changing);
+	    changing = erts_smp_atomic32_read_nob(&schdlr_sspnd.changing);
 	}
 
-	active_schedulers = erts_smp_atomic32_inctest(&schdlr_sspnd.active);
-	changing = erts_smp_atomic32_read(&schdlr_sspnd.changing);
+	active_schedulers = erts_smp_atomic32_inc_read_nob(&schdlr_sspnd.active);
+	changing = erts_smp_atomic32_read_nob(&schdlr_sspnd.changing);
 	if ((changing & ERTS_SCHDLR_SSPND_CHNG_MSB)
 	    && schdlr_sspnd.online == active_schedulers) {
-	    erts_smp_atomic32_band(&schdlr_sspnd.changing,
-				   ~ERTS_SCHDLR_SSPND_CHNG_MSB);
+	    erts_smp_atomic32_read_band_nob(&schdlr_sspnd.changing,
+					    ~ERTS_SCHDLR_SSPND_CHNG_MSB);
 	}
 
 	ASSERT(no <= schdlr_sspnd.online);
-	ASSERT(!erts_smp_atomic32_read(&schdlr_sspnd.msb.ongoing));
+	ASSERT(!ongoing_multi_scheduling_block());
 
     }
 
@@ -3235,7 +3238,7 @@ do {									\
     (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_band(&(RQ)->info_flags, ~ERTS_RUNQ_IFLG_SUSPENDED);\
+    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;				\
@@ -3279,7 +3282,7 @@ erts_schedulers_state(Uint *total,
     int res;
     erts_aint32_t changing;
     erts_smp_mtx_lock(&schdlr_sspnd.mtx);
-    changing = erts_smp_atomic32_read(&schdlr_sspnd.changing);
+    changing = erts_smp_atomic32_read_nob(&schdlr_sspnd.changing);
     if (yield_allowed && (changing & ~ERTS_SCHDLR_SSPND_CHNG_WAITER))
 	res = ERTS_SCHDLR_SSPND_YIELD_RESTART;
     else {
@@ -3310,7 +3313,7 @@ erts_set_schedulers_online(Process *p,
     have_unlocked_plocks = 0;
     no = (int) new_no;
 
-    changing = erts_smp_atomic32_read(&schdlr_sspnd.changing);
+    changing = erts_smp_atomic32_read_nob(&schdlr_sspnd.changing);
     if (changing) {
 	res = ERTS_SCHDLR_SSPND_YIELD_RESTART;
     }
@@ -3385,8 +3388,8 @@ erts_set_schedulers_online(Process *p,
 		    for (ix = no; ix < online; ix++) {
 			ErtsSchedulerSleepInfo *ssi;
 			ssi = ERTS_SCHED_SLEEP_INFO_IX(ix);
-			erts_smp_atomic32_bor(&ssi->flags,
-					      ERTS_SSI_FLG_SUSPENDED);
+			erts_smp_atomic32_read_bor_nob(&ssi->flags,
+						       ERTS_SSI_FLG_SUSPENDED);
 		    }
 		    wake_all_schedulers();
 		}
@@ -3433,11 +3436,11 @@ erts_set_schedulers_online(Process *p,
 				  NULL);
 	    ASSERT(res != ERTS_SCHDLR_SSPND_DONE
 		   ? (ERTS_SCHDLR_SSPND_CHNG_WAITER
-		      & erts_smp_atomic32_read(&schdlr_sspnd.changing))
+		      & erts_smp_atomic32_read_nob(&schdlr_sspnd.changing))
 		   : (ERTS_SCHDLR_SSPND_CHNG_WAITER
-		      == erts_smp_atomic32_read(&schdlr_sspnd.changing)));
-	    erts_smp_atomic32_band(&schdlr_sspnd.changing,
-				   ~ERTS_SCHDLR_SSPND_CHNG_WAITER);
+		      == erts_smp_atomic32_read_nob(&schdlr_sspnd.changing)));
+	    erts_smp_atomic32_read_band_nob(&schdlr_sspnd.changing,
+					    ~ERTS_SCHDLR_SSPND_CHNG_WAITER);
 	}
     }
 
@@ -3456,7 +3459,7 @@ erts_block_multi_scheduling(Process *p, ErtsProcLocks plocks, int on, int all)
     ErtsProcList *plp;
 
     erts_smp_mtx_lock(&schdlr_sspnd.mtx);
-    changing = erts_smp_atomic32_read(&schdlr_sspnd.changing);
+    changing = erts_smp_atomic32_read_nob(&schdlr_sspnd.changing);
     if (changing) {
 	res = ERTS_SCHDLR_SSPND_YIELD_RESTART; /* Yield */
     }
@@ -3466,7 +3469,7 @@ erts_block_multi_scheduling(Process *p, ErtsProcLocks plocks, int on, int all)
 	    plp->next = schdlr_sspnd.msb.procs;
 	    schdlr_sspnd.msb.procs = plp;
 	    p->flags |= F_HAVE_BLCKD_MSCHED;
-	    ASSERT(erts_smp_atomic32_read(&schdlr_sspnd.active) == 1);
+	    ASSERT(erts_smp_atomic32_read_nob(&schdlr_sspnd.active) == 1);
 	    ASSERT(p->scheduler_data->no == 1);
 	    res = ERTS_SCHDLR_SSPND_DONE_MSCHED_BLOCKED;
 	}
@@ -3477,11 +3480,11 @@ erts_block_multi_scheduling(Process *p, ErtsProcLocks plocks, int on, int all)
 		have_unlocked_plocks = 1;
 		erts_smp_proc_unlock(p, plocks);
 	    }
-	    ASSERT(0 == erts_smp_atomic32_read(&schdlr_sspnd.msb.ongoing));
-	    erts_smp_atomic32_set(&schdlr_sspnd.msb.ongoing, 1);
+	    ASSERT(!ongoing_multi_scheduling_block());
+	    schdlr_sspnd.msb.ongoing = 1;
 	    if (online == 1) {
 		res = ERTS_SCHDLR_SSPND_DONE_MSCHED_BLOCKED;
-		ASSERT(erts_smp_atomic32_read(&schdlr_sspnd.active) == 1);
+		ASSERT(erts_smp_atomic32_read_nob(&schdlr_sspnd.active) == 1);
 		ASSERT(p->scheduler_data->no == 1);
 	    }
 	    else {
@@ -3501,8 +3504,8 @@ erts_block_multi_scheduling(Process *p, ErtsProcLocks plocks, int on, int all)
 		}
 		if (erts_common_run_queue) {
 		    for (ix = 1; ix < online; ix++)
-			erts_smp_atomic32_bor(&ERTS_SCHED_SLEEP_INFO_IX(ix)->flags,
-					      ERTS_SSI_FLG_SUSPENDED);
+			erts_smp_atomic32_read_bor_nob(&ERTS_SCHED_SLEEP_INFO_IX(ix)->flags,
+						       ERTS_SSI_FLG_SUSPENDED);
 		    wake_all_schedulers();
 		}
 		else {
@@ -3530,7 +3533,7 @@ erts_block_multi_scheduling(Process *p, ErtsProcLocks plocks, int on, int all)
 					susp_sched_prep_block,
 					susp_sched_resume_block,
 					NULL);
-		while (erts_smp_atomic32_read(&schdlr_sspnd.active)
+		while (erts_smp_atomic32_read_nob(&schdlr_sspnd.active)
 		       != schdlr_sspnd.msb.wait_active)
 		    erts_smp_cnd_wait(&schdlr_sspnd.cnd, &schdlr_sspnd.mtx);
 		erts_smp_activity_end(ERTS_ACTIVITY_WAIT,
@@ -3539,11 +3542,11 @@ erts_block_multi_scheduling(Process *p, ErtsProcLocks plocks, int on, int all)
 				      NULL);
 		ASSERT(res != ERTS_SCHDLR_SSPND_DONE_MSCHED_BLOCKED
 		       ? (ERTS_SCHDLR_SSPND_CHNG_WAITER
-			  & erts_smp_atomic32_read(&schdlr_sspnd.changing))
+			  & erts_smp_atomic32_read_nob(&schdlr_sspnd.changing))
 		       : (ERTS_SCHDLR_SSPND_CHNG_WAITER
-			  == erts_smp_atomic32_read(&schdlr_sspnd.changing)));
-		erts_smp_atomic32_band(&schdlr_sspnd.changing,
-				       ~ERTS_SCHDLR_SSPND_CHNG_WAITER);
+			  == erts_smp_atomic32_read_nob(&schdlr_sspnd.changing)));
+		erts_smp_atomic32_read_band_nob(&schdlr_sspnd.changing,
+						~ERTS_SCHDLR_SSPND_CHNG_WAITER);
 	    }
 	    plp = proclist_create(p);
 	    plp->next = schdlr_sspnd.msb.procs;
@@ -3610,16 +3613,16 @@ erts_block_multi_scheduling(Process *p, ErtsProcLocks plocks, int on, int all)
 	    });
 #endif
 	    p->flags &= ~F_HAVE_BLCKD_MSCHED;
-	    erts_smp_atomic32_set(&schdlr_sspnd.msb.ongoing, 0);
+	    schdlr_sspnd.msb.ongoing = 0;
 	    if (schdlr_sspnd.online == 1) {
 		/* No schedulers to resume */
-		ASSERT(erts_smp_atomic32_read(&schdlr_sspnd.active) == 1);
+		ASSERT(erts_smp_atomic32_read_nob(&schdlr_sspnd.active) == 1);
 		ERTS_SCHDLR_SSPND_CHNG_SET(0, ERTS_SCHDLR_SSPND_CHNG_MSB);
 	    }
 	    else if (erts_common_run_queue) {
 		for (ix = 1; ix < schdlr_sspnd.online; ix++)
-		    erts_smp_atomic32_band(&ERTS_SCHED_SLEEP_INFO_IX(ix)->flags,
-					   ~ERTS_SSI_FLG_SUSPENDED);
+		    erts_smp_atomic32_read_band_nob(&ERTS_SCHED_SLEEP_INFO_IX(ix)->flags,
+						    ~ERTS_SSI_FLG_SUSPENDED);
 		wake_all_schedulers();
 	    }
 	    else {
@@ -3669,7 +3672,7 @@ void
 erts_dbg_multi_scheduling_return_trap(Process *p, Eterm return_value)
 {
     if (return_value == am_blocked) {
-	erts_aint32_t active = erts_smp_atomic32_read(&schdlr_sspnd.active);
+	erts_aint32_t active = erts_smp_atomic32_read_nob(&schdlr_sspnd.active);
 	ASSERT(1 <= active && active <= 2);
 	ASSERT(ERTS_PROC_GET_SCHDATA(p)->no == 1);
     }
@@ -3752,12 +3755,12 @@ sched_thread_func(void *vesdp)
     erts_thread_init_float();
     erts_smp_mtx_lock(&schdlr_sspnd.mtx);
 
-    ASSERT(erts_smp_atomic32_read(&schdlr_sspnd.changing)
+    ASSERT(erts_smp_atomic32_read_nob(&schdlr_sspnd.changing)
 	   & ERTS_SCHDLR_SSPND_CHNG_ONLN);
 
     if (--schdlr_sspnd.curr_online == schdlr_sspnd.wait_curr_online) {
-	erts_smp_atomic32_band(&schdlr_sspnd.changing,
-			       ~ERTS_SCHDLR_SSPND_CHNG_ONLN);
+	erts_smp_atomic32_read_band_nob(&schdlr_sspnd.changing,
+					~ERTS_SCHDLR_SSPND_CHNG_ONLN);
 	if (((ErtsSchedulerData *) vesdp)->no != 1)
 	    erts_smp_cnd_signal(&schdlr_sspnd.cnd);
     }
@@ -5214,7 +5217,7 @@ Process *schedule(Process *p, int calls)
 	    reds = ERTS_PROC_MIN_CONTEXT_SWITCH_REDS_COST;
 	esdp->virtual_reds = 0;
 
-	fcalls = (int) erts_smp_atomic32_addtest(&function_calls, reds);
+	fcalls = (int) erts_smp_atomic32_add_read_acqb(&function_calls, reds);
 	ASSERT(esdp && esdp == erts_get_scheduler_data());
 
 	rq = erts_get_runq_current(esdp);
@@ -5349,7 +5352,7 @@ Process *schedule(Process *p, int calls)
 	    if ((rq->flags & ERTS_RUNQ_FLG_SUSPENDED)
 		|| (erts_smp_atomic32_read_acqb(&esdp->ssi->flags)
 		    & ERTS_SSI_FLG_SUSPENDED)) {
-		ASSERT(erts_smp_atomic32_read(&esdp->ssi->flags)
+		ASSERT(erts_smp_atomic32_read_nob(&esdp->ssi->flags)
 		       & ERTS_SSI_FLG_SUSPENDED);
 		suspend_scheduler(esdp);
 	    }
@@ -5363,7 +5366,7 @@ Process *schedule(Process *p, int calls)
 	|| defined(ERTS_SCHED_NEED_NONBLOCKABLE_AUX_WORK)
 	{
 	    ErtsSchedulerSleepInfo *ssi = esdp->ssi;
-	    erts_aint32_t aux_work = erts_smp_atomic32_read(&ssi->aux_work);
+	    erts_aint32_t aux_work = erts_smp_atomic32_read_nob(&ssi->aux_work);
 	    if (aux_work) {
 		erts_smp_runq_unlock(rq);
 #ifdef ERTS_SCHED_NEED_BLOCKABLE_AUX_WORK
@@ -5407,7 +5410,7 @@ Process *schedule(Process *p, int calls)
 		if ((rq->flags & ERTS_RUNQ_FLG_SUSPENDED)
 		    || (erts_smp_atomic32_read_acqb(&esdp->ssi->flags)
 			& ERTS_SSI_FLG_SUSPENDED)) {
-		    ASSERT(erts_smp_atomic32_read(&esdp->ssi->flags)
+		    ASSERT(erts_smp_atomic32_read_nob(&esdp->ssi->flags)
 			   & ERTS_SSI_FLG_SUSPENDED);
 		    non_empty_runq(rq);
 		    goto continue_check_activities_to_run;
@@ -5948,7 +5951,7 @@ erts_test_next_pid(int set, Uint next)
 
 Uint erts_process_count(void)
 {
-    erts_aint32_t res = erts_smp_atomic32_read(&process_count);
+    erts_aint32_t res = erts_smp_atomic32_read_nob(&process_count);
     ASSERT(res >= 0);
     return (Uint) res;
 }
@@ -5997,7 +6000,7 @@ alloc_process(void)
     ASSERT(!process_tab[p_next]);
 
     process_tab[p_next] = p;
-    erts_smp_atomic32_inc(&process_count);
+    erts_smp_atomic32_inc_nob(&process_count);
     p->id = make_internal_pid(p_serial << p_serial_shift | p_next);
     if (p->id == ERTS_INVALID_PID) {
 	/* Do not use the invalid pid; change serial */
@@ -6123,7 +6126,7 @@ erl_create_process(Process* parent, /* Parent of process (default group leader).
 	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(&erts_max_gen_gcs);
+	p->max_gen_gcs    = (Uint16) erts_smp_atomic32_read_nob(&erts_max_gen_gcs);
     }
     p->skipped = 0;
     ASSERT(p->min_heap_size == erts_next_heap_size(p->min_heap_size, 0));
@@ -7580,8 +7583,8 @@ continue_exit_process(Process *p
 	p->status_flags = 0;
 #endif
 	process_tab[pix] = NULL; /* Time of death! */
-	ASSERT(erts_smp_atomic32_read(&process_count) > 0);
-	erts_smp_atomic32_dec(&process_count);
+	ASSERT(erts_smp_atomic32_read_nob(&process_count) > 0);
+	erts_smp_atomic32_dec_nob(&process_count);
 
 #ifdef ERTS_SMP
 	erts_pix_unlock(pix_lock);