Perform full GC if incremental marking is completed or marking deque is empty.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index d4550949035c07e573287a67ce0596a885c5d064..bc55f9e1c5f8fb88a9a3db623d2dba0efd3bc2d9 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -827,7 +827,8 @@ bool Heap::CollectGarbage(GarbageCollector collector, const char* gc_reason,
     const intptr_t kStepSizeWhenDelayedByScavenge = 1 * MB;
     incremental_marking()->Step(kStepSizeWhenDelayedByScavenge,
                                 IncrementalMarking::NO_GC_VIA_STACK_GUARD);
-    if (!incremental_marking()->IsComplete() && !FLAG_gc_global) {
+    if (!incremental_marking()->IsComplete() &&
+        !mark_compact_collector_.marking_deque_.IsEmpty() && !FLAG_gc_global) {

[jochen (gone - plz use gerrit), 2015/01/26 14:09:01]

should this check for overflow as well?

[Hannes Payer (out of office), 2015/01/26 14:52:45]

An overflowed marking deque will be full.

       if (FLAG_trace_incremental_marking) {
         PrintF("[IncrementalMarking] Delaying MarkSweep.\n");
       }