Massive patch for the first months work adding System FC to GHC #35

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

diff --git a/rts/Capability.c b/rts/Capability.c
index e384e1e..99c68fd 100644 (file)
--- a/rts/Capability.c
+++ b/rts/Capability.c
@@ -646,7 +646,13 @@ shutdownCapability (Capability *cap, Task *task)
 
     task->cap = cap;
 
-    for (i = 0; i < 50; i++) {
+    // Loop indefinitely until all the workers have exited and there
+    // are no Haskell threads left.  We used to bail out after 50
+    // iterations of this loop, but that occasionally left a worker
+    // running which caused problems later (the closeMutex() below
+    // isn't safe, for one thing).
+
+    for (i = 0; /* i < 50 */; i++) {
        debugTrace(DEBUG_sched, 
                   "shutting down capability %d, attempt %d", cap->no, i);
        ACQUIRE_LOCK(&cap->lock);
@@ -672,8 +678,10 @@ shutdownCapability (Capability *cap, Task *task)
     // we now have the Capability, its run queue and spare workers
     // list are both empty.
 
-    // We end up here only in THREADED_RTS
-    closeMutex(&cap->lock);
+    // ToDo: we can't drop this mutex, because there might still be
+    // threads performing foreign calls that will eventually try to 
+    // return via resumeThread() and attempt to grab cap->lock.
+    // closeMutex(&cap->lock);
 }
 
 /* ----------------------------------------------------------------------------