Allow main thread to contribute to the sweeping phase.

src/spaces.h

 // 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.
 
 #ifndef V8_SPACES_H_
 #define V8_SPACES_H_
 
 #include "src/allocation.h"
 #include "src/base/atomicops.h"
 #include "src/base/platform/mutex.h"
@@ skipping 1996 matching lines @@
 
   // Expands the space by allocating a fixed number of pages. Returns false if
   // it cannot allocate requested number of pages from OS, or if the hard heap
   // size limit has been hit.
   bool Expand();
 
   // Generic fast case allocation function that tries linear allocation at the
   // address denoted by top in allocation_info_.
   inline HeapObject* AllocateLinearly(int size_in_bytes);
 
-  MUST_USE_RESULT HeapObject*
-      WaitForSweeperThreadsAndRetryAllocation(int size_in_bytes);
+  // If sweeping is still in progress try to sweep unswept pages. If that is
+  // not successful, wait for the sweeper threads and re-try free-list
+  // allocation.
+  MUST_USE_RESULT HeapObject* EnsureSweepingProgress(int size_in_bytes);
 
   // Slow path of AllocateRaw.  This function is space-dependent.
   MUST_USE_RESULT HeapObject* SlowAllocateRaw(int size_in_bytes);
 
   friend class PageIterator;
   friend class MarkCompactCollector;
 };
 
 
 class NumberAndSizeInfo BASE_EMBEDDED {
@@ skipping 985 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_