Use acquire/release stores and loads when reading and writing the parallel sweeping state of a page.

src/spaces.h

 // Copyright 2011 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 466 matching lines @@
   // PARALLEL_SWEEPING_PENDING - This page is ready for parallel sweeping.
   enum ParallelSweepingState {
     PARALLEL_SWEEPING_DONE,
     PARALLEL_SWEEPING_FINALIZE,
     PARALLEL_SWEEPING_IN_PROGRESS,
     PARALLEL_SWEEPING_PENDING
   };
 
   ParallelSweepingState parallel_sweeping() {
     return static_cast<ParallelSweepingState>(
-        NoBarrier_Load(&parallel_sweeping_));
+        Acquire_Load(&parallel_sweeping_));
   }
 
   void set_parallel_sweeping(ParallelSweepingState state) {
-    NoBarrier_Store(&parallel_sweeping_, state);
+    Release_Store(&parallel_sweeping_, state);
   }
 
   bool TryParallelSweeping() {
-    return NoBarrier_CompareAndSwap(&parallel_sweeping_,
-                                    PARALLEL_SWEEPING_PENDING,
-                                    PARALLEL_SWEEPING_IN_PROGRESS) ==
-                                        PARALLEL_SWEEPING_PENDING;
+    return Acquire_CompareAndSwap(&parallel_sweeping_,
+                                  PARALLEL_SWEEPING_PENDING,
+                                  PARALLEL_SWEEPING_IN_PROGRESS) ==
+                                      PARALLEL_SWEEPING_PENDING;
   }
 
   // Manage live byte count (count of bytes known to be live,
   // because they are marked black).
   void ResetLiveBytes() {
     if (FLAG_gc_verbose) {
       PrintF("ResetLiveBytes:%p:%x->0\n",
              static_cast<void*>(this), live_byte_count_);
     }
     live_byte_count_ = 0;
@@ skipping 2472 matching lines @@
   }
   // Must be small, since an iteration is used for lookup.
   static const int kMaxComments = 64;
 };
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_SPACES_H_