Use a lock in pages to synchronize sweeper threads to allow others to wait on concurrently swept pa…

src/heap/spaces.cc

 // Copyright 2011 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.
 
 #include "src/v8.h"
 
 #include "src/base/bits.h"
 #include "src/base/platform/platform.h"
 #include "src/full-codegen.h"
 #include "src/heap/mark-compact.h"
@@ skipping 481 matching lines @@
   chunk->area_end_ = area_end;
   chunk->flags_ = 0;
   chunk->set_owner(owner);
   chunk->InitializeReservedMemory();
   chunk->slots_buffer_ = NULL;
   chunk->skip_list_ = NULL;
   chunk->write_barrier_counter_ = kWriteBarrierCounterGranularity;
   chunk->progress_bar_ = 0;
   chunk->high_water_mark_ = static_cast<int>(area_start - base);
   chunk->set_parallel_sweeping(SWEEPING_DONE);
+  chunk->mutex_ = NULL;
   chunk->available_in_small_free_list_ = 0;
   chunk->available_in_medium_free_list_ = 0;
   chunk->available_in_large_free_list_ = 0;
   chunk->available_in_huge_free_list_ = 0;
   chunk->non_available_small_blocks_ = 0;
   chunk->ResetLiveBytes();
   Bitmap::Clear(chunk);
   chunk->initialize_scan_on_scavenge(false);
   chunk->SetFlag(WAS_SWEPT);
 
@@ skipping 246 matching lines @@
     ObjectSpace space =
         static_cast<ObjectSpace>(1 << chunk->owner()->identity());
     PerformAllocationCallback(space, kAllocationActionFree, chunk->size());
   }
 
   isolate_->heap()->RememberUnmappedPage(reinterpret_cast<Address>(chunk),
                                          chunk->IsEvacuationCandidate());
 
   delete chunk->slots_buffer();
   delete chunk->skip_list();
+  delete chunk->mutex();
 
   base::VirtualMemory* reservation = chunk->reserved_memory();
   if (reservation->IsReserved()) {
     FreeMemory(reservation, chunk->executable());
   } else {
     FreeMemory(chunk->address(), chunk->size(), chunk->executable());
   }
 }
 
 
@@ skipping 2361 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }  // namespace internal
 }  // namespace v8