Improved scheduler suspend functionality

- The calling process is now suspended while synchronizing
  scheduler suspends via erlang:system_flag(schedulers_online, _)
  and erlang:system_flag(multi_scheduling, _), instead of blocking
  the scheduler thread in the BIF call waiting for the operation
  to synchronize. Besides releasing the scheduler for other work
  (or immediate suspend) it also makes it possible to abort the
  operation by killing the process.
- erlang:system_flag(schedulers_online, _) now only wait for normal
  schedulers to complete before it returns. This since it may take
  a very long time before all dirty schedulers suspends.
- erlang:system_flag(multi_scheduling, block_normal|unblock_normal)
  which only operate on normal schedulers has been introduced. This
  since there are use cases where suspend of dirty schedulers are
  not of interest (hipe loader).
- erlang:system_flag(multi_scheduling, block) still blocks all
  dirty schedulers as well as all normal schedulers except one since
  it is hard to redefine what multi scheduling block means.
- The three operations:
  - changing amount of schedulers online
  - blocking/unblocking normal multi scheduling
  - blocking/unblocking full multi scheduling
  can now be done in parallel. This is important since otherwise
  a full multi scheduling block would potentially delay the other
  operations for a very long time.

1 files changed, 114 insertions, 58 deletions

diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 39eb257c2c..8c748c9bf7 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -320,13 +320,11 @@ erts_print_system_version(int to, void *arg, Process *c_p)
     char *ov = otp_version;
 #ifdef ERTS_SMP
     Uint total, online, active;
-#ifdef ERTS_DIRTY_SCHEDULERS
     Uint dirty_cpu, dirty_cpu_onln, dirty_io;
 
-    (void) erts_schedulers_state(&total, &online, &active, &dirty_cpu, &dirty_cpu_onln, &dirty_io, 0);
-#else
-    (void) erts_schedulers_state(&total, &online, &active, NULL, NULL, NULL, 0);
-#endif
+    erts_schedulers_state(&total, &online, &active,
+			  &dirty_cpu, &dirty_cpu_onln, NULL,
+			  &dirty_io, NULL);
 #endif
     for (i = 0; i < sizeof(otp_version)-4; i++) {
 	if (ov[i] == '-' && ov[i+1] == 'r' && ov[i+2] == 'c')
@@ -2044,12 +2042,18 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
 #ifndef ERTS_SMP
 	BIF_RET(am_disabled);
 #else
+#ifndef ERTS_DIRTY_SCHEDULERS
 	if (erts_no_schedulers == 1)
 	    BIF_RET(am_disabled);
-	else {
-	    BIF_RET(erts_is_multi_scheduling_blocked()
-		    ? am_blocked
-		    : am_enabled);
+	else
+#endif
+	{
+	    int msb = erts_is_multi_scheduling_blocked();
+	    BIF_RET(!msb
+		    ? am_enabled
+		    : (msb > 0
+		       ? am_blocked
+		       : am_blocked_normal));
 	}
 #endif
     } else if (BIF_ARG_1 == am_build_type) {
@@ -2518,77 +2522,120 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
 	res = TUPLE3(hp, make_small(1), make_small(1), make_small(1));
 	BIF_RET(res);
 #else
+	Eterm *hp;
 	Uint total, online, active;
-	switch (erts_schedulers_state(&total,
-				      &online,
-				      &active,
-				      NULL,
-				      NULL,
-				      NULL,
-				      1)) {
-	case ERTS_SCHDLR_SSPND_DONE: {
-	    Eterm *hp = HAlloc(BIF_P, 4);
-	    res = TUPLE3(hp,
-			 make_small(total),
-			 make_small(online),
-			 make_small(active));
-	    BIF_RET(res);
+	erts_schedulers_state(&total, &online, &active,
+			      NULL, NULL, NULL, NULL, NULL);
+	hp = HAlloc(BIF_P, 4);
+	res = TUPLE3(hp,
+		     make_small(total),
+		     make_small(online),
+		     make_small(active));
+	BIF_RET(res);
+#endif
+    } else if (ERTS_IS_ATOM_STR("schedulers_state", BIF_ARG_1)) {
+#ifndef ERTS_SMP
+	Eterm *hp = HAlloc(BIF_P, 4);
+	res = TUPLE3(hp, make_small(1), make_small(1), make_small(1));
+	BIF_RET(res);
+#else
+	Eterm *hp;
+	Uint total, online, active;
+	erts_schedulers_state(&total, &online, &active,
+			      NULL, NULL, NULL, NULL, NULL);
+	hp = HAlloc(BIF_P, 4);
+	res = TUPLE3(hp,
+		     make_small(total),
+		     make_small(online),
+		     make_small(active));
+	BIF_RET(res);
+#endif
+    } else if (ERTS_IS_ATOM_STR("all_schedulers_state", BIF_ARG_1)) {
+#ifndef ERTS_SMP
+	Eterm *hp = HAlloc(BIF_P, 2+5);
+	res = CONS(hp+5,
+		   TUPLE4(hp,
+			  am_normal,
+			  make_small(1),
+			  make_small(1),
+			  make_small(1)),
+		   NIL);
+	BIF_RET(res);
+#else
+	Eterm *hp, tpl;
+	Uint sz, total, online, active,
+	    dirty_cpu_total, dirty_cpu_online, dirty_cpu_active,
+	    dirty_io_total, dirty_io_active;
+	erts_schedulers_state(&total, &online, &active,
+			      &dirty_cpu_total, &dirty_cpu_online, &dirty_cpu_active,
+			      &dirty_io_total, &dirty_io_active);
+
+	sz = 2+5;
+	if (dirty_cpu_total)
+	    sz += 2+5;
+	if (dirty_io_total)
+	    sz += 2+5;
+
+	hp = HAlloc(BIF_P, sz);
+
+	res = NIL;
+	if (dirty_io_total) {
+	    tpl = TUPLE4(hp,
+			 am_dirty_io,
+			 make_small(dirty_io_total),
+			 make_small(dirty_io_total),
+			 make_small(dirty_io_active));
+	    hp += 5;
+	    res = CONS(hp, tpl, res);
+	    hp += 2;
 	}
-	case ERTS_SCHDLR_SSPND_YIELD_RESTART:
-	    ERTS_VBUMP_ALL_REDS(BIF_P);
-	    BIF_TRAP1(bif_export[BIF_system_info_1],
-		      BIF_P, BIF_ARG_1);
-	default:
-	    ASSERT(0);
-	    BIF_ERROR(BIF_P, EXC_INTERNAL_ERROR);
+	if (dirty_cpu_total) {
+	    tpl = TUPLE4(hp,
+			 am_dirty_cpu,
+			 make_small(dirty_cpu_total),
+			 make_small(dirty_cpu_online),
+			 make_small(dirty_cpu_active));
+	    hp += 5;
+	    res = CONS(hp, tpl, res);
+	    hp += 2;
 	}
+	tpl = TUPLE4(hp,
+		     am_normal,
+		     make_small(total),
+		     make_small(online),
+		     make_small(active));
+	hp += 5;
+	res = CONS(hp, tpl, res);
+	BIF_RET(res);
 #endif
     } else if (ERTS_IS_ATOM_STR("schedulers_online", BIF_ARG_1)) {
 #ifndef ERTS_SMP
 	BIF_RET(make_small(1));
 #else
-	Uint total, online, active;
-	switch (erts_schedulers_state(&total, &online, &active, NULL, NULL, NULL, 1)) {
-	case ERTS_SCHDLR_SSPND_DONE:
-	    BIF_RET(make_small(online));
-	case ERTS_SCHDLR_SSPND_YIELD_RESTART:
-	    ERTS_VBUMP_ALL_REDS(BIF_P);
-	    BIF_TRAP1(bif_export[BIF_system_info_1],
-		      BIF_P, BIF_ARG_1);
-	default:
-	    ASSERT(0);
-	    BIF_ERROR(BIF_P, EXC_INTERNAL_ERROR);
-	}
+	Uint online;
+	erts_schedulers_state(NULL, &online, NULL, NULL, NULL, NULL, NULL, NULL);
+	BIF_RET(make_small(online));
 #endif
     } else if (ERTS_IS_ATOM_STR("schedulers_active", BIF_ARG_1)) {
 #ifndef ERTS_SMP
 	BIF_RET(make_small(1));
 #else
-	Uint total, online, active;
-	switch (erts_schedulers_state(&total, &online, &active, NULL, NULL, NULL, 1)) {
-	case ERTS_SCHDLR_SSPND_DONE:
-	    BIF_RET(make_small(active));
-	case ERTS_SCHDLR_SSPND_YIELD_RESTART:
-	    ERTS_VBUMP_ALL_REDS(BIF_P);
-	    BIF_TRAP1(bif_export[BIF_system_info_1],
-		      BIF_P, BIF_ARG_1);
-	default:
-	    ASSERT(0);
-	    BIF_ERROR(BIF_P, EXC_INTERNAL_ERROR);
-	}
+	Uint active;
+	erts_schedulers_state(NULL, NULL, &active, NULL, NULL, NULL, NULL, NULL);
+	BIF_RET(make_small(active));
 #endif
 #if defined(ERTS_SMP) && defined(ERTS_DIRTY_SCHEDULERS)
     } else if (ERTS_IS_ATOM_STR("dirty_cpu_schedulers", BIF_ARG_1)) {
 	Uint dirty_cpu;
-	erts_schedulers_state(NULL, NULL, NULL, &dirty_cpu, NULL, NULL, 1);
+	erts_schedulers_state(NULL, NULL, NULL, &dirty_cpu, NULL, NULL, NULL, NULL);
 	BIF_RET(make_small(dirty_cpu));
     } else if (ERTS_IS_ATOM_STR("dirty_cpu_schedulers_online", BIF_ARG_1)) {
 	Uint dirty_cpu_onln;
-	erts_schedulers_state(NULL, NULL, NULL, NULL, &dirty_cpu_onln, NULL, 1);
+	erts_schedulers_state(NULL, NULL, NULL, NULL, &dirty_cpu_onln, NULL, NULL, NULL);
 	BIF_RET(make_small(dirty_cpu_onln));
     } else if (ERTS_IS_ATOM_STR("dirty_io_schedulers", BIF_ARG_1)) {
 	Uint dirty_io;
-	erts_schedulers_state(NULL, NULL, NULL, NULL, NULL, &dirty_io, 1);
+	erts_schedulers_state(NULL, NULL, NULL, NULL, NULL, NULL, &dirty_io, NULL);
 	BIF_RET(make_small(dirty_io));
 #endif
     } else if (ERTS_IS_ATOM_STR("run_queues", BIF_ARG_1)) {
@@ -2642,7 +2689,16 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
 	if (erts_no_schedulers == 1)
 	    BIF_RET(NIL);
 	else
-	    BIF_RET(erts_multi_scheduling_blockers(BIF_P));
+	    BIF_RET(erts_multi_scheduling_blockers(BIF_P, 0));
+#endif
+    } else if (ERTS_IS_ATOM_STR("normal_multi_scheduling_blockers", BIF_ARG_1)) {
+#ifndef ERTS_SMP
+	BIF_RET(NIL);
+#else
+	if (erts_no_schedulers == 1)
+	    BIF_RET(NIL);
+	else
+	    BIF_RET(erts_multi_scheduling_blockers(BIF_P, 1));
 #endif
     } else if (ERTS_IS_ATOM_STR("modified_timing_level", BIF_ARG_1)) {
 	BIF_RET(ERTS_USE_MODIFIED_TIMING()