void MarkSweep::restore_marks() {

  {- -------------------------------------------
  (1) (assert)
      ---------------------------------------- -}

      assert(_preserved_oop_stack.size() == _preserved_mark_stack.size(),
             "inconsistent preserved oop stacks");

  {- -------------------------------------------
  (1) (トレース出力)
      ---------------------------------------- -}

      if (PrintGC && Verbose) {
        gclog_or_tty->print_cr("Restoring %d marks",
                               _preserved_count + _preserved_oop_stack.size());
      }

  {- -------------------------------------------
  (1) まず _preserved_marks の中に入っている全て oop について, 
      PreservedMark::restore() で mark 値の復帰処理を行う.
      ---------------------------------------- -}

      // restore the marks we saved earlier
      for (size_t i = 0; i < _preserved_count; i++) {
        _preserved_marks[i].restore();
      }

  {- -------------------------------------------
  (1) 次に, _preserved_oop_stack 内の全ての oop について, 
      oopDesc::set_mark() で mark 値の復帰処理を行う.
      ---------------------------------------- -}

      // deal with the overflow
      while (!_preserved_oop_stack.is_empty()) {
        oop obj       = _preserved_oop_stack.pop();
        markOop mark  = _preserved_mark_stack.pop();
        obj->set_mark(mark);
      }
    }