Remove sequential sweeping mode and perform lazy sweeping when no sweeper threads are active.

src/heap.cc

 // Copyright 2012 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/accessors.h"
 #include "src/api.h"
 #include "src/base/once.h"
 #include "src/base/utils/random-number-generator.h"
@@ skipping 3294 matching lines @@
 
   Page* page = Page::FromAddress(address);
   // We can move the object start if:
   // (1) the object is not in old pointer or old data space,
   // (2) the page of the object was already swept,
   // (3) the page was already concurrently swept. This case is an optimization
   // for concurrent sweeping. The WasSwept predicate for concurrently swept
   // pages is set after sweeping all pages.
   return (!is_in_old_pointer_space && !is_in_old_data_space) ||
          page->WasSwept() ||
-         (mark_compact_collector()->AreSweeperThreadsActivated() &&
-              page->parallel_sweeping() <=
-                  MemoryChunk::PARALLEL_SWEEPING_FINALIZE);
+         (page->parallel_sweeping() <=
+             MemoryChunk::PARALLEL_SWEEPING_FINALIZE);
 }
 
 
 void Heap::AdjustLiveBytes(Address address, int by, InvocationMode mode) {
   if (incremental_marking()->IsMarking() &&
       Marking::IsBlack(Marking::MarkBitFrom(address))) {
     if (mode == FROM_GC) {
       MemoryChunk::IncrementLiveBytesFromGC(address, by);
     } else {
       MemoryChunk::IncrementLiveBytesFromMutator(address, by);
@@ skipping 1004 matching lines @@
   }
 
   if (mark_sweeps_since_idle_round_started_ >= kMaxMarkSweepsInIdleRound) {
     FinishIdleRound();
     return true;
   }
 
   // If the IdleNotifcation is called with a large hint we will wait for
   // the sweepter threads here.
   if (hint >= kMinHintForFullGC &&
-      mark_compact_collector()->IsConcurrentSweepingInProgress()) {
-    mark_compact_collector()->WaitUntilSweepingCompleted();
+      mark_compact_collector()->sweeping_in_progress()) {
+    mark_compact_collector()->EnsureSweepingCompleted();
   }
 
   return false;
 }
 
 
 bool Heap::IdleGlobalGC() {
   static const int kIdlesBeforeScavenge = 4;
   static const int kIdlesBeforeMarkSweep = 7;
   static const int kIdlesBeforeMarkCompact = 8;
@@ skipping 2061 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 
 } }  // namespace v8::internal