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

src/incremental-marking.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/incremental-marking.h"
 
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
@@ skipping 518 matching lines @@
   }
   ASSERT(FLAG_incremental_marking);
   ASSERT(FLAG_incremental_marking_steps);
   ASSERT(state_ == STOPPED);
   ASSERT(heap_->gc_state() == Heap::NOT_IN_GC);
   ASSERT(!heap_->isolate()->serializer_enabled());
   ASSERT(heap_->isolate()->IsInitialized());
 
   ResetStepCounters();
 
-  if (!heap_->mark_compact_collector()->IsConcurrentSweepingInProgress()) {
+  if (!heap_->mark_compact_collector()->sweeping_in_progress()) {
     StartMarking(flag);
   } else {
     if (FLAG_trace_incremental_marking) {
       PrintF("[IncrementalMarking] Start sweeping.\n");
     }
     state_ = SWEEPING;
   }
 
   heap_->new_space()->LowerInlineAllocationLimit(kAllocatedThreshold);
 }
@@ skipping 326 matching lines @@
   bytes_scanned_ += bytes_to_process;
 
   double start = 0;
 
   if (FLAG_trace_incremental_marking || FLAG_trace_gc ||
       FLAG_print_cumulative_gc_stat) {
     start = base::OS::TimeCurrentMillis();
   }
 
   if (state_ == SWEEPING) {
-    if (heap_->mark_compact_collector()->IsConcurrentSweepingInProgress() &&
+    if (heap_->mark_compact_collector()->sweeping_in_progress() &&
         heap_->mark_compact_collector()->IsSweepingCompleted()) {
-      heap_->mark_compact_collector()->WaitUntilSweepingCompleted();
+      heap_->mark_compact_collector()->EnsureSweepingCompleted();
     }
-    if (!heap_->mark_compact_collector()->IsConcurrentSweepingInProgress()) {
+    if (!heap_->mark_compact_collector()->sweeping_in_progress()) {
       bytes_scanned_ = 0;
       StartMarking(PREVENT_COMPACTION);
     }
   } else if (state_ == MARKING) {
     ProcessMarkingDeque(bytes_to_process);
     if (marking_deque_.IsEmpty()) MarkingComplete(action);
   }
 
   steps_count_++;
   steps_count_since_last_gc_++;
@@ skipping 88 matching lines @@
   bytes_scanned_ = 0;
   write_barriers_invoked_since_last_step_ = 0;
 }
 
 
 int64_t IncrementalMarking::SpaceLeftInOldSpace() {
   return heap_->MaxOldGenerationSize() - heap_->PromotedSpaceSizeOfObjects();
 }
 
 } }  // namespace v8::internal