Forward transition objects to grey if they are referenced by a large object

src/incremental-marking-inl.h

Index: src/incremental-marking-inl.h
diff --git a/src/incremental-marking-inl.h b/src/incremental-marking-inl.h
index bbe9a9d209b36cca76360b2f9b091b755dc0587a..dcac917e8c547742b090ff4d0665b0fea2d86f97 100644
--- a/src/incremental-marking-inl.h
+++ b/src/incremental-marking-inl.h
@@ -37,14 +37,20 @@ namespace internal {
 bool IncrementalMarking::BaseRecordWrite(HeapObject* obj,
                                          Object** slot,
                                          Object* value) {
-  MarkBit value_bit = Marking::MarkBitFrom(HeapObject::cast(value));
+  HeapObject* value_heap_obj = HeapObject::cast(value);
+  MarkBit value_bit = Marking::MarkBitFrom(value_heap_obj);
   if (Marking::IsWhite(value_bit)) {
     MarkBit obj_bit = Marking::MarkBitFrom(obj);
     if (Marking::IsBlack(obj_bit)) {
-      BlackToGreyAndUnshift(obj, obj_bit);
+      // TODO(hpayer): make decision based on if object has a progress bar
+      const int kLargeObjectSize = 1024 * 1024;
+      if (obj->Size() > kLargeObjectSize) {
+        WhiteToGreyAndPush(value_heap_obj, value_bit);
+      } else {
+        BlackToGreyAndUnshift(obj, obj_bit);
+      }
       RestartIfNotMarking();
     }
-
     // Object is either grey or white.  It will be scanned if survives.
     return false;

[Michael Starzinger, 2012/11/14 08:42:24]

This will prevent the slot from being recorded when we do a forward
white-to-grey transition. Compaction might corrupt the pointer. In the case of a
white-to-grey transition we need to fall through to the code below.

[payer, 2012/11/14 09:12:37]

Done.

   }