void MemoryService::track_memory_pool_usage(MemoryPool* pool) {

  {- -------------------------------------------
  (1) MemoryPool::record_peak_memory_usage() を呼び出し, 最大使用量等の情報を更新する.
      ---------------------------------------- -}

      // Track the peak memory usage
      pool->record_peak_memory_usage();

  {- -------------------------------------------
  (1) (JMM のフック点) (See: LowMemoryDetector)
      ---------------------------------------- -}

      // Detect low memory
      if (LowMemoryDetector::is_enabled(pool)) {
        LowMemoryDetector::detect_low_memory(pool);
      }
    }