[heap] Start concurrent marking simultaneously with incremental marking.

src/heap/concurrent-marking.h

 // Copyright 2017 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_HEAP_CONCURRENT_MARKING_
 #define V8_HEAP_CONCURRENT_MARKING_
 
 #include <vector>
 
 #include "src/allocation.h"
@@ skipping 10 matching lines @@
 class ConcurrentMarking {
  public:
   explicit ConcurrentMarking(Heap* heap);
   ~ConcurrentMarking();
 
   void AddRoot(HeapObject* object);
 
   void StartMarkingTask();
   void WaitForTaskToComplete();
 
+  bool IsMarkingInProgress() { return is_task_pending_; }

[Hannes Payer (out of office), 2017/03/08 12:58:50]

IsInProgress

[ulan, 2017/03/10 16:45:26]

I named it IsTaskPending().

+
  private:
   class Task;
   Heap* heap_;
-  base::Semaphore pending_task_;
+  base::Semaphore pending_task_semaphore_;

[Michael Lippautz, 2017/03/08 19:14:34]

super nit (feel free to ignore): We could align naming with Sweeper here (names
are pending_sweeper_tasks_semaphore_ , sweeping_in_progress_)

[ulan, 2017/03/10 16:45:26]

We will probably (re-)start the tasks multiple times in one marking round. I'll
keep the flag task specific.

   std::vector<HeapObject*> root_set_;
+  bool is_task_pending_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_PAGE_PARALLEL_JOB_