void PSRefProcTaskExecutor::execute(ProcessTask& task)
{

  {- -------------------------------------------
  (1) GCTaskQueue::create() で GCTaskQueue を作り, 
      そこに ParallelGCThreads 個分だけ PSRefProcTaskProxy をつめる.
      ---------------------------------------- -}

      GCTaskQueue* q = GCTaskQueue::create();
      for(uint i=0; i<ParallelGCThreads; i++) {
        q->enqueue(new PSRefProcTaskProxy(task, i));
      }

  {- -------------------------------------------
  (1) さらに, ParallelGCThreads 個分だけ StealTask を追加.
      ---------------------------------------- -}

      ParallelTaskTerminator terminator(
                     ParallelScavengeHeap::gc_task_manager()->workers(),
                     (TaskQueueSetSuper*) PSPromotionManager::stack_array_depth());
      if (task.marks_oops_alive() && ParallelGCThreads > 1) {
        for (uint j=0; j<ParallelGCThreads; j++) {
          q->enqueue(new StealTask(&terminator));
        }
      }

  {- -------------------------------------------
  (1) GCTaskManager::execute_and_wait() で, GCTaskThread 達に実行させる.
      ---------------------------------------- -}

      ParallelScavengeHeap::gc_task_manager()->execute_and_wait(q);
    }