Delegate the queuing of cleared references to managed code.

Previously, the garbage collector would pass each cleared reference to
the heap worker thread for queuing.  The heap worker thread would then
perform a callback into managed code for each cleared reference which
assigned the reference to its reference queue.

With this change, the garbage collector instead links together all of
the cleared references and calls back into managed code exactly once
to hand off the references for processing.  This change makes the heap
worker thread and its data structures obsolete.

Change-Id: I28e02638f0877a7fd2ac96b9c3f5597a38541ebb

1 files changed, 27 insertions, 27 deletions

diff --git a/vm/alloc/MarkSweep.c b/vm/alloc/MarkSweep.c
index 69b75de3f..e26394c85 100644
--- a/vm/alloc/MarkSweep.c
+++ b/vm/alloc/MarkSweep.c
@@ -20,7 +20,6 @@
 #include "alloc/HeapBitmapInlines.h"
 #include "alloc/HeapInternal.h"
 #include "alloc/HeapSource.h"
-#include "alloc/HeapWorker.h"
 #include "alloc/MarkSweep.h"
 #include "alloc/Visit.h"
 #include "alloc/VisitInlines.h"
@@ -342,8 +341,6 @@ static void verifyImmuneObjects()
  * - Primitive classes
  * - Special objects
  *   - gDvm.outOfMemoryObj
- * - Objects allocated with ALLOC_NO_GC
- * - Objects pending finalization (but not yet finalized)
  * - Objects in debugger object registry
  *
  * Don't need:
@@ -795,11 +792,7 @@ static void enqueueReference(Object *ref)
     assert(ref != NULL);
     assert(dvmGetFieldObject(ref, gDvm.offJavaLangRefReference_queue) != NULL);
     assert(dvmGetFieldObject(ref, gDvm.offJavaLangRefReference_queueNext) == NULL);
-    if (!dvmHeapAddRefToLargeTable(&gDvm.gcHeap->referenceOperations, ref)) {
-        LOGE_HEAP("enqueueReference(): no room for any more "
-                  "reference operations\n");
-        dvmAbort();
-    }
+    enqueuePendingReference(ref, &gDvm.gcHeap->clearedReferences);
 }
 
 /*
@@ -857,11 +850,9 @@ static void clearWhiteReferences(Object **list)
     GcMarkContext *ctx;
     Object *ref, *referent;
     size_t referentOffset;
-    bool doSignal;
 
     ctx = &gDvm.gcHeap->markContext;
     referentOffset = gDvm.offJavaLangRefReference_referent;
-    doSignal = false;
     while (*list != NULL) {
         ref = dequeuePendingReference(list);
         referent = dvmGetFieldObject(ref, referentOffset);
@@ -870,31 +861,23 @@ static void clearWhiteReferences(Object **list)
             clearReference(ref);
             if (isEnqueuable(ref)) {
                 enqueueReference(ref);
-                doSignal = true;
             }
         }
     }
-    /*
-     * If we cleared a reference with a reference queue we must notify
-     * the heap worker to append the reference.
-     */
-    if (doSignal) {
-        dvmSignalHeapWorker(false);
-    }
     assert(*list == NULL);
 }
 
 /*
  * Enqueues finalizer references with white referents.  White
- * referents are blackened, moved to the pendingNext field, and the
+ * referents are blackened, moved to the zombie field, and the
  * referent field is cleared.
  */
 static void enqueueFinalizerReferences(Object **list)
 {
     GcMarkContext *ctx = &gDvm.gcHeap->markContext;
     size_t referentOffset = gDvm.offJavaLangRefReference_referent;
-    size_t pendingNextOffset = gDvm.offJavaLangRefReference_pendingNext;
-    bool doSignal = false;
+    size_t zombieOffset = gDvm.offJavaLangRefFinalizerReference_zombie;
+    bool hasEnqueued = false;
     while (*list != NULL) {
         Object *ref = dequeuePendingReference(list);
         Object *referent = dvmGetFieldObject(ref, referentOffset);
@@ -902,15 +885,14 @@ static void enqueueFinalizerReferences(Object **list)
             markObject(referent, ctx);
             /* If the referent is non-null the reference must queuable. */
             assert(isEnqueuable(ref));
-            dvmSetFieldObject(ref, pendingNextOffset, referent);
+            dvmSetFieldObject(ref, zombieOffset, referent);
             clearReference(ref);
             enqueueReference(ref);
-            doSignal = true;
+            hasEnqueued = true;
         }
     }
-    if (doSignal) {
+    if (hasEnqueued) {
         processMarkStack(ctx);
-        dvmSignalHeapWorker(false);
     }
     assert(*list == NULL);
 }
@@ -928,8 +910,8 @@ void dvmSetFinalizable(Object *obj)
     assert(self != NULL);
     Method *meth = gDvm.methJavaLangRefFinalizerReferenceAdd;
     assert(meth != NULL);
-    JValue unused;
-    dvmCallMethod(self, meth, obj, &unused, obj);
+    JValue unusedResult;
+    dvmCallMethod(self, meth, NULL, &unusedResult, obj);
 }
 
 /*
@@ -982,6 +964,24 @@ void dvmHeapProcessReferences(Object **softReferences, bool clearSoftRefs,
     assert(*phantomReferences == NULL);
 }
 
+/*
+ * Pushes a list of cleared references out to the managed heap.
+ */
+void dvmEnqueueClearedReferences(Object **cleared)
+{
+    assert(cleared != NULL);
+    if (*cleared != NULL) {
+        Thread *self = dvmThreadSelf();
+        assert(self != NULL);
+        Method *meth = gDvm.methJavaLangRefReferenceQueueAdd;
+        assert(meth != NULL);
+        JValue unused;
+        Object *reference = *cleared;
+        dvmCallMethod(self, meth, NULL, &unused, reference);
+        *cleared = NULL;
+    }
+}
+
 void dvmHeapFinishMarkStep()
 {
     GcMarkContext *ctx;