debugTrace(DEBUG_sched, "--++ thread %lu (%s) finished",
(unsigned long)t->id, whatNext_strs[t->what_next]);
+ // blocked exceptions can now complete, even if the thread was in
+ // blocked mode (see #2910). This unconditionally calls
+ // lockTSO(), which ensures that we don't miss any threads that
+ // are engaged in throwTo() with this thread as a target.
+ awakenBlockedExceptionQueue (cap, t);
+
//
// Check whether the thread that just completed was a bound
// thread, and if so return with the result.
heap_census = scheduleNeedHeapProfile(rtsTrue);
+ if (recent_activity == ACTIVITY_INACTIVE && force_major)
+ {
+ // We are doing a GC because the system has been idle for a
+ // timeslice and we need to check for deadlock. Record the
+ // fact that we've done a GC and turn off the timer signal;
+ // it will get re-enabled if we run any threads after the GC.
+ //
+ // Note: this is done before GC, because after GC there might
+ // be threads already running (GarbageCollect() releases the
+ // GC threads when it completes), so we risk turning off the
+ // timer signal when it should really be on.
+ recent_activity = ACTIVITY_DONE_GC;
+ stopTimer();
+ }
+
#if defined(THREADED_RTS)
debugTrace(DEBUG_sched, "doing GC");
// reset waiting_for_gc *before* GC, so that when the GC threads
balanceSparkPoolsCaps(n_capabilities, capabilities);
#endif
- if (force_major)
- {
- // We've just done a major GC and we don't need the timer
- // signal turned on any more (#1623).
- // NB. do this *before* releasing the Capabilities, to avoid
- // deadlocks!
- recent_activity = ACTIVITY_DONE_GC;
- stopTimer();
- }
-
#if defined(THREADED_RTS)
if (gc_type == PENDING_GC_SEQ) {
// release our stash of capabilities.
debugTrace(DEBUG_sched, "thread %lu: re-entering RTS", (unsigned long)tso->id);
if (tso->why_blocked == BlockedOnCCall) {
- awakenBlockedExceptionQueue(cap,tso);
+ // avoid locking the TSO if we don't have to
+ if (tso->blocked_exceptions != END_TSO_QUEUE) {
+ awakenBlockedExceptionQueue(cap,tso);
+ }
tso->flags &= ~(TSO_BLOCKEX | TSO_INTERRUPTIBLE);
}