Parallelize marking phase of mark-sweep/compact collection cycle.

src/spaces.cc

 // Copyright 2006-2008 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 2886 matching lines @@
 }
 
 
 void LargeObjectSpace::FreeUnmarkedObjects() {
   LargeObjectChunk* previous = NULL;
   LargeObjectChunk* current = first_chunk_;
   while (current != NULL) {
     HeapObject* object = current->GetObject();
     if (object->IsMarked()) {
       object->ClearMark();
+#ifdef DEBUG
       MarkCompactCollector::tracer()->decrement_marked_count();
+#endif
       previous = current;
       current = current->next();
     } else {
       Page* page = Page::FromAddress(RoundUp(current->address(),
                                      Page::kPageSize));
       Executability executable =
           page->IsPageExecutable() ? EXECUTABLE : NOT_EXECUTABLE;
       Address chunk_address = current->address();
       size_t chunk_size = current->size();
 
@@ skipping 122 matching lines @@
   for (HeapObject* obj = obj_it.next(); obj != NULL; obj = obj_it.next()) {
     if (obj->IsCode()) {
       Code* code = Code::cast(obj);
       code_kind_statistics[code->kind()] += code->Size();
     }
   }
 }
 #endif  // DEBUG
 
 } }  // namespace v8::internal