X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=rts%2FCapability.c;h=ffaa372f98abe16f2eecc935c00f09140c73af24;hp=f1c625ef7c44b28eb3ce74eb467de9404088becc;hb=b19ba85c6ec3504a66b33243cfb43599d8c298a7;hpb=9cef40bd4dd2536c7a370a1a9b78461c152805cc

diff --git a/rts/Capability.c b/rts/Capability.c
index f1c625e..ffaa372 100644
--- a/rts/Capability.c
+++ b/rts/Capability.c
@@ -639,7 +639,7 @@ prodOneCapability (void)
  * ------------------------------------------------------------------------- */
 
 void
-shutdownCapability (Capability *cap, Task *task)
+shutdownCapability (Capability *cap, Task *task, rtsBool safe)
 {
     nat i;
 
@@ -664,6 +664,30 @@ shutdownCapability (Capability *cap, Task *task)
 	    continue;
 	}
 	cap->running_task = task;
+
+        if (cap->spare_workers) {
+            // Look for workers that have died without removing
+            // themselves from the list; this could happen if the OS
+            // summarily killed the thread, for example.  This
+            // actually happens on Windows when the system is
+            // terminating the program, and the RTS is running in a
+            // DLL.
+            Task *t, *prev;
+            prev = NULL;
+            for (t = cap->spare_workers; t != NULL; t = t->next) {
+                if (!osThreadIsAlive(t->id)) {
+                    debugTrace(DEBUG_sched, 
+                               "worker thread %p has died unexpectedly", (void *)t->id);
+                        if (!prev) {
+                            cap->spare_workers = t->next;
+                        } else {
+                            prev->next = t->next;
+                        }
+                        prev = t;
+                }
+            }
+        }
+
 	if (!emptyRunQueue(cap) || cap->spare_workers) {
 	    debugTrace(DEBUG_sched, 
 		       "runnable threads or workers still alive, yielding");
@@ -672,7 +696,24 @@ shutdownCapability (Capability *cap, Task *task)
 	    yieldThread();
 	    continue;
 	}
+
+        // If "safe", then busy-wait for any threads currently doing
+        // foreign calls.  If we're about to unload this DLL, for
+        // example, we need to be sure that there are no OS threads
+        // that will try to return to code that has been unloaded.
+        // We can be a bit more relaxed when this is a standalone
+        // program that is about to terminate, and let safe=false.
+        if (cap->suspended_ccalling_tasks && safe) {
+	    debugTrace(DEBUG_sched, 
+		       "thread(s) are involved in foreign calls, yielding");
+            cap->running_task = NULL;
+	    RELEASE_LOCK(&cap->lock);
+            yieldThread();
+            continue;
+        }
+            
 	debugTrace(DEBUG_sched, "capability %d is stopped.", cap->no);
+        freeCapability(cap);
 	RELEASE_LOCK(&cap->lock);
 	break;
     }
@@ -710,4 +751,11 @@ tryGrabCapability (Capability *cap, Task *task)
 
 #endif /* THREADED_RTS */
 
+void
+freeCapability (Capability *cap) {
+    stgFree(cap->mut_lists);
+#if defined(THREADED_RTS) || defined(PARALLEL_HASKELL)
+    freeSparkPool(&cap->r.rSparks);
+#endif
+}