X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=rts%2FCapability.c;h=fa7f63069f0b909f758ea18db0beacc207ef08de;hb=a9afdc24b1b2bbe63d71e8e2890770edfa8a6a8d;hp=73a3427d7eb2838f5b443b6370de7411849ebea3;hpb=c7c9df49873a5316afac360f9ac2d8da432b40f1;p=ghc-hetmet.git

diff --git a/rts/Capability.c b/rts/Capability.c
index 73a3427..fa7f630 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;
 
@@ -696,8 +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);
+        freeCapability(cap);
 	RELEASE_LOCK(&cap->lock);
 	break;
     }
@@ -743,3 +759,77 @@ freeCapability (Capability *cap) {
 #endif
 }
 
+/* ---------------------------------------------------------------------------
+   Mark everything directly reachable from the Capabilities.  When
+   using multiple GC threads, each GC thread marks all Capabilities
+   for which (c `mod` n == 0), for Capability c and thread n.
+   ------------------------------------------------------------------------ */
+
+void
+markSomeCapabilities (evac_fn evac, void *user, nat i0, nat delta)
+{
+    nat i;
+    Capability *cap;
+    Task *task;
+
+    // Each GC thread is responsible for following roots from the
+    // Capability of the same number.  There will usually be the same
+    // or fewer Capabilities as GC threads, but just in case there
+    // are more, we mark every Capability whose number is the GC
+    // thread's index plus a multiple of the number of GC threads.
+    for (i = i0; i < n_capabilities; i += delta) {
+	cap = &capabilities[i];
+	evac(user, (StgClosure **)(void *)&cap->run_queue_hd);
+	evac(user, (StgClosure **)(void *)&cap->run_queue_tl);
+#if defined(THREADED_RTS)
+	evac(user, (StgClosure **)(void *)&cap->wakeup_queue_hd);
+	evac(user, (StgClosure **)(void *)&cap->wakeup_queue_tl);
+#endif
+	for (task = cap->suspended_ccalling_tasks; task != NULL; 
+	     task=task->next) {
+	    debugTrace(DEBUG_sched,
+		       "evac'ing suspended TSO %lu", (unsigned long)task->suspended_tso->id);
+	    evac(user, (StgClosure **)(void *)&task->suspended_tso);
+	}
+    }
+    
+#if !defined(THREADED_RTS)
+    evac(user, (StgClosure **)(void *)&blocked_queue_hd);
+    evac(user, (StgClosure **)(void *)&blocked_queue_tl);
+    evac(user, (StgClosure **)(void *)&sleeping_queue);
+#endif 
+}
+
+// Sparks are not roots for GC, so we don't mark them in
+// markSomeCapabilities().  Instead, we traverse the spark queues
+// after GC and throw away any that are unreachable.
+void
+updateCapabilitiesPostGC (void)
+{
+#if defined(THREADED_RTS)
+    nat i;
+    for (i = 0; i < n_capabilities; i++) {
+        updateSparkQueue (&capabilities[i]);
+    }
+#endif // THREADED_RTS
+}
+
+// This function is used by the compacting GC to thread all the
+// pointers from spark queues.
+void
+traverseSparkQueues (evac_fn evac USED_IF_THREADS, void *user USED_IF_THREADS)
+{
+#if defined(THREADED_RTS)
+    nat i;
+    for (i = 0; i < n_capabilities; i++) {
+        traverseSparkQueue (evac, user, &capabilities[i]);
+    }
+#endif // THREADED_RTS
+
+}
+
+void
+markCapabilities (evac_fn evac, void *user)
+{
+    markSomeCapabilities(evac, user, 0, 1);
+}