Replace system block with thread progress block

The ERTS internal system block functionality has been replaced by
new functionality for blocking the system. The old system block
functionality had contention issues and complexity issues. The
new functionality piggy-backs on thread progress tracking functionality
needed by newly introduced lock-free synchronization in the runtime
system. When the functionality for blocking the system isn't used
there is more or less no overhead at all. This since the functionality
for tracking thread progress is there and needed anyway.

2 files changed, 10 insertions, 15 deletions

diff --git a/erts/emulator/sys/common/erl_check_io.c b/erts/emulator/sys/common/erl_check_io.c
index 6d4ad459cc..ba88fd1d39 100644
--- a/erts/emulator/sys/common/erl_check_io.c
+++ b/erts/emulator/sys/common/erl_check_io.c
@@ -35,6 +35,7 @@
 #include "sys.h"
 #include "global.h"
 #include "erl_check_io.h"
+#include "erl_thr_progress.h"
 
 #ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
 #  define ERTS_DRV_EV_STATE_EXTRA_SIZE 128
@@ -1164,7 +1165,6 @@ ERTS_CIO_EXPORT(erts_check_io)(int do_wait)
 #ifdef ERTS_ENABLE_LOCK_CHECK
     erts_lc_check_exact(NULL, 0); /* No locks should be locked */
 #endif
-    erts_smp_activity_begin(ERTS_ACTIVITY_WAIT, NULL, NULL, NULL);
     pollres_len = sizeof(pollres)/sizeof(ErtsPollResFd);
 
     erts_smp_atomic_set_nob(&pollset.in_poll_wait, 1);
@@ -1174,7 +1174,6 @@ ERTS_CIO_EXPORT(erts_check_io)(int do_wait)
 #ifdef ERTS_ENABLE_LOCK_CHECK
     erts_lc_check_exact(NULL, 0); /* No locks should be locked */
 #endif
-    erts_smp_activity_end(ERTS_ACTIVITY_WAIT, NULL, NULL, NULL);
 
     erts_deliver_time(); /* sync the machine's idea of time */
 
@@ -1881,13 +1880,12 @@ ERTS_CIO_EXPORT(erts_check_io_debug)(void)
 
     erts_printf("--- fds in pollset --------------------------------------\n");
 
-#ifdef ERTS_SMP
-# ifdef ERTS_ENABLE_LOCK_CHECK
+#if defined(ERTS_SMP) && defined(ERTS_ENABLE_LOCK_CHECK)
     erts_lc_check_exact(NULL, 0); /* No locks should be locked */
-# endif
-    erts_block_system(0); /* stop the world to avoid messy locking */
 #endif
 
+    erts_smp_thr_progress_block(); /* stop the world to avoid messy locking */
+
 #ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
     counters.epep = erts_alloc(ERTS_ALC_T_TMP, sizeof(ErtsPollEvents)*max_fds);
     ERTS_POLL_EXPORT(erts_poll_get_selected_events)(pollset.ps, counters.epep, max_fds);
@@ -1909,9 +1907,7 @@ ERTS_CIO_EXPORT(erts_check_io_debug)(void)
     safe_hash_for_each(&drv_ev_state_tab, &doit_erts_check_io_debug, (void *) &counters);
 #endif
 
-#ifdef ERTS_SMP
-    erts_release_system();
-#endif
+    erts_smp_thr_progress_unblock();
 
     erts_printf("\n");
     erts_printf("used fds=%d\n", counters.used_fds);
diff --git a/erts/emulator/sys/common/erl_mseg.c b/erts/emulator/sys/common/erl_mseg.c
index 3a90db607b..49750ff6ce 100644
--- a/erts/emulator/sys/common/erl_mseg.c
+++ b/erts/emulator/sys/common/erl_mseg.c
@@ -38,6 +38,7 @@
 #include "erl_time.h"
 #include "erl_alloc.h"
 #include "big.h"
+#include "erl_thr_progress.h"
 
 #if HAVE_ERTS_MSEG
 
@@ -450,14 +451,12 @@ mseg_recreate(ErtsMsegAllctr_t *ma, MemKind* mk, void *old_seg, Uint old_size, U
 do {									\
     if ((MA)->is_thread_safe)						\
 	ERTS_LC_ASSERT(erts_lc_mtx_is_locked(&(MA)->mtx)		\
-		       || erts_smp_is_system_blocked(0)			\
-		       || (ERTS_IS_CRASH_DUMPING			\
-			   && erts_smp_is_system_blocked(ERTS_BS_FLG_ALLOW_GC)));\
+		       || erts_smp_thr_progress_is_blocking()		\
+		       || ERTS_IS_CRASH_DUMPING);			\
     else								\
 	ERTS_LC_ASSERT((MA)->ix == (int) erts_get_scheduler_id()	\
-		       || erts_smp_is_system_blocked(0)			\
-		       || (ERTS_IS_CRASH_DUMPING			\
-			   && erts_smp_is_system_blocked(ERTS_BS_FLG_ALLOW_GC)));\
+		       || erts_smp_thr_progress_is_blocking()		\
+		       || ERTS_IS_CRASH_DUMPING);			\
 } while (0)
 #define ERTS_DBG_MK_CHK_THR_ACCESS(MK) \
   ERTS_DBG_MA_CHK_THR_ACCESS((MK)->ma)