target = target->_link;
goto retry;
}
+ // check again for ThreadComplete and ThreadKilled. This
+ // cooperates with scheduleHandleThreadFinished to ensure
+ // that we never miss any threads that are throwing an
+ // exception to a thread in the process of terminating.
+ if (target->what_next == ThreadComplete
+ || target->what_next == ThreadKilled) {
+ unlockTSO(target);
+ return THROWTO_SUCCESS;
+ }
blockedThrowTo(cap,source,target);
*out = target;
return THROWTO_BLOCKED;
void
awakenBlockedExceptionQueue (Capability *cap, StgTSO *tso)
{
- if (tso->blocked_exceptions != END_TSO_QUEUE) {
- lockTSO(tso);
- awakenBlockedQueue(cap, tso->blocked_exceptions);
- tso->blocked_exceptions = END_TSO_QUEUE;
- unlockTSO(tso);
- }
+ lockTSO(tso);
+ awakenBlockedQueue(cap, tso->blocked_exceptions);
+ tso->blocked_exceptions = END_TSO_QUEUE;
+ unlockTSO(tso);
}
static void
(unsigned long)t->id, whatNext_strs[t->what_next]);
// blocked exceptions can now complete, even if the thread was in
- // blocked mode (see #2910). The thread is already marked
- // ThreadComplete, so any further throwTos will complete
- // immediately and we don't need to worry about synchronising with
- // those.
+ // 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);
//
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);
}