putMVar and takeMVar: add write_barrier() to fix race with throwTo

[ghc-hetmet.git] / rts / Schedule.c

diff --git a/rts/Schedule.c b/rts/Schedule.c
index 33715b1..7c453d7 100644 (file)
--- a/rts/Schedule.c
+++ b/rts/Schedule.c
@@ -777,9 +777,11 @@ schedulePushWork(Capability *cap USED_IF_THREADS,
 
     // Check whether we have more threads on our run queue, or sparks
     // in our pool, that we could hand to another Capability.
-    if ((emptyRunQueue(cap) || cap->run_queue_hd->_link == END_TSO_QUEUE)
-       && sparkPoolSizeCap(cap) < 2) {
-       return;
+    if (cap->run_queue_hd == END_TSO_QUEUE) {
+        if (sparkPoolSizeCap(cap) < 2) return;
+    } else {
+        if (cap->run_queue_hd->_link == END_TSO_QUEUE &&
+            sparkPoolSizeCap(cap) < 1) return;
     }
 
     // First grab as many free Capabilities as we can.
@@ -1400,6 +1402,13 @@ scheduleHandleThreadFinished (Capability *cap STG_UNUSED, Task *task, StgTSO *t)
     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).  The thread is already marked
+    // ThreadComplete, so any further throwTos will complete
+    // immediately and we don't need to worry about synchronising with
+    // those.
+    awakenBlockedExceptionQueue (cap, t);
+
       //
       // Check whether the thread that just completed was a bound
       // thread, and if so return with the result.