Add basic support for parallel compaction and flag.

src/heap/mark-compact.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_MARK_COMPACT_H_
 #define V8_HEAP_MARK_COMPACT_H_
 
 #include "src/base/bits.h"
 #include "src/heap/spaces.h"
 
@@ skipping 650 matching lines @@
   bool IsSlotInBlackObject(Page* p, Address slot, HeapObject** out_object);
   bool IsSlotInBlackObjectSlow(Page* p, Address slot);
   bool IsSlotInLiveObject(Address slot);
   void VerifyIsSlotInLiveObject(Address slot, HeapObject* object);
 
   // Removes all the slots in the slot buffers that are within the given
   // address range.
   void RemoveObjectSlots(Address start_slot, Address end_slot);
 
  private:
+  class CompactionTask;
   class SweeperTask;
 
   explicit MarkCompactCollector(Heap* heap);
   ~MarkCompactCollector();
 
   bool WillBeDeoptimized(Code* code);
   void EvictPopularEvacuationCandidate(Page* page);
   void ClearInvalidStoreAndSlotsBufferEntries();
 
   void StartSweeperThreads();
@@ skipping 17 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_in_progress_;
 
+  // Synchronize sweeper threads.
   base::Semaphore pending_sweeper_jobs_semaphore_;
 
+  // Synchronize compaction threads.
+  base::Semaphore pending_compaction_jobs_semaphore_;
+
   bool evacuation_;
 
   SlotsBufferAllocator slots_buffer_allocator_;
 
   SlotsBuffer* migration_slots_buffer_;
 
   // Finishes GC, performs heap verification if enabled.
   void Finish();
 
   // -----------------------------------------------------------------------
@@ skipping 138 matching lines @@
 
   int DiscoverAndEvacuateBlackObjectsOnPage(NewSpace* new_space,
                                             NewSpacePage* p);
 
   void EvacuateNewSpace();
 
   void EvacuateLiveObjectsFromPage(Page* p);
 
   void EvacuatePages();
 
+  void EvacuatePagesInParallel();
+
   void EvacuateNewSpaceAndCandidates();
 
   void ReleaseEvacuationCandidates();
 
   // Moves the pages of the evacuation_candidates_ list to the end of their
   // corresponding space pages list.
   void MoveEvacuationCandidatesToEndOfPagesList();
 
   void SweepSpace(PagedSpace* space, SweeperType sweeper);
 
@@ skipping 84 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_MARK_COMPACT_H_