Wait for sweeper threads in EnsureSweeperProgress() only if the main thread finished its sweeping p…

src/mark-compact.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 680 matching lines @@
   void WaitUntilSweepingCompleted();
 
   intptr_t StealMemoryFromSweeperThreads(PagedSpace* space);
 
   bool AreSweeperThreadsActivated();
 
   bool IsConcurrentSweepingInProgress();
 
   void FinalizeSweeping();
 
+  void set_sequential_sweeping(bool sequential_sweeping) {
+    sequential_sweeping_ = sequential_sweeping;
+  }
+
+  bool sequential_sweeping() const {
+    return sequential_sweeping_;
+  }
+
   // Parallel marking support.
   void MarkInParallel();
 
   void WaitUntilMarkingCompleted();
 
  private:
   MarkCompactCollector();
   ~MarkCompactCollector();
 
   bool MarkInvalidatedCode();
@@ skipping 31 matching lines @@
 
   // True if we are collecting slots to perform evacuation from evacuation
   // candidates.
   bool compacting_;
 
   bool was_marked_incrementally_;
 
   // True if concurrent or parallel sweeping is currently in progress.
   bool sweeping_pending_;
 
+  bool sequential_sweeping_;
+
   // A pointer to the current stack-allocated GC tracer object during a full
   // collection (NULL before and after).
   GCTracer* tracer_;
 
   SlotsBufferAllocator slots_buffer_allocator_;
 
   SlotsBuffer* migration_slots_buffer_;
 
   // Finishes GC, performs heap verification if enabled.
   void Finish();
@@ skipping 135 matching lines @@
   CodeFlusher* code_flusher_;
   Object* encountered_weak_maps_;
 
   List<Page*> evacuation_candidates_;
   List<Code*> invalidated_code_;
 
   friend class Heap;
 };
 
 
+class SweepingScope BASE_EMBEDDED {

[Michael Starzinger, 2013/03/05 17:20:11]

Naming this "SequentialSweepingScope" would be more intuitive.

[Hannes Payer (out of office), 2013/03/05 17:27:04]

Done.

+ public:
+  explicit SweepingScope(MarkCompactCollector *collector) :
+    collector_(collector) {
+    collector_->set_sequential_sweeping(true);
+  }
+
+  ~SweepingScope() {
+    collector_->set_sequential_sweeping(false);
+  }
+
+ private:
+  MarkCompactCollector* collector_;
+};
+
+
 const char* AllocationSpaceName(AllocationSpace space);
 
 } }  // namespace v8::internal
 
 #endif  // V8_MARK_COMPACT_H_