index 79b9627831fcadd07d6d0a4378a7f12988bc24aa..eacf8d51ea0833462966b151f46f099630e10ba2 100644 (file)
InitLatch(Latch *latch)
{
latch->is_set = false;
+ latch->maybe_sleeping = false;
latch->owner_pid = MyProcPid;
latch->is_shared = false;
#endif
latch->is_set = false;
+ latch->maybe_sleeping = false;
latch->owner_pid = 0;
latch->is_shared = true;
}
latch->is_set = true;
+ pg_memory_barrier();
+ if (!latch->maybe_sleeping)
+ return;
+
#ifndef WIN32
/*
{
/* Only the owner should reset the latch */
Assert(latch->owner_pid == MyProcPid);
+ Assert(latch->maybe_sleeping == false);
latch->is_set = false;
* ordering, so that we cannot miss seeing is_set if a notification
* has already been queued.
*/
+ if (set->latch && !set->latch->is_set)
+ {
+ /* about to sleep on a latch */
+ set->latch->maybe_sleeping = true;
+ pg_memory_barrier();
+ /* and recheck */
+ }
+
if (set->latch && set->latch->is_set)
{
occurred_events->fd = PGINVALID_SOCKET;
@@ -1280,6 +1295,9 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
occurred_events++;
returned_events++;
+ /* could have been set above */
+ set->latch->maybe_sleeping = false;
+
break;
}
rc = WaitEventSetWaitBlock(set, cur_timeout,
occurred_events, nevents);
+ if (set->latch)
+ {
+ Assert(set->latch->maybe_sleeping);
+ set->latch->maybe_sleeping = false;
+ }
+
if (rc == -1)
break; /* timeout occurred */
else