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

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 1747 matching lines @@
     ASSERT(ShouldBeSweptLazily(p));
     unswept_free_bytes_ -= (p->area_size() - p->LiveBytes());
   }
 
   void ResetUnsweptFreeBytes() {
     unswept_free_bytes_ = 0;
   }
 
   bool AdvanceSweeper(intptr_t bytes_to_sweep);
 
-  // When parallel sweeper threads are active this function waits
-  // for them to complete, otherwise AdvanceSweeper with size_in_bytes
-  // is called.
+  // When parallel sweeper threads are active and the main thread finished
+  // its sweeping phase, this function waits for them to complete, otherwise
+  // AdvanceSweeper with size_in_bytes is called.
   bool EnsureSweeperProgress(intptr_t size_in_bytes);
 
   bool IsLazySweepingComplete() {
     return !first_unswept_page_->is_valid();
   }
 
   Page* FirstPage() { return anchor_.next_page(); }
   Page* LastPage() { return anchor_.prev_page(); }
 
   void CountFreeListItems(Page* p, FreeList::SizeStats* sizes) {
@@ skipping 1042 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_