HeapWord* GenCollectedHeap::mem_allocate(size_t size,
                                         bool is_large_noref,
                                         bool is_tlab,
                                         bool* gc_overhead_limit_was_exceeded) {

  {- -------------------------------------------
  (1) GenCollectorPolicy::mem_allocate_work() を呼び出すだけ.
      ---------------------------------------- -}

      return collector_policy()->mem_allocate_work(size,
                                                   is_tlab,
                                                   gc_overhead_limit_was_exceeded);
    }