// This closure is applied to the fields of the objects that have just been copied.

template <class T> inline void G1ParScanClosure::do_oop_nv(T* p) {

  {- -------------------------------------------
  (1) 以下の 3通りのどれかを行う.
      * 引数で渡されたポインタが NULL の場合には何もしない.
      * NULL でなく, かつ collection set を指しているようであれば,
        _par_scan_state というフィールドに格納している G1ParScanThreadState オブジェクトに
        そのポインタを詰めていく.
      * NULL でなく, collection set を指していない場合には,
        G1ParScanThreadState::update_rs() で Remembered Set(G1RemSet オブジェクト) を更新する処理を行う.
      ---------------------------------------- -}

      T heap_oop = oopDesc::load_heap_oop(p);

      if (!oopDesc::is_null(heap_oop)) {
        oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
        if (_g1->in_cset_fast_test(obj)) {
          // We're not going to even bother checking whether the object is
          // already forwarded or not, as this usually causes an immediate
          // stall. We'll try to prefetch the object (for write, given that
          // we might need to install the forwarding reference) and we'll
          // get back to it when pop it from the queue
          Prefetch::write(obj->mark_addr(), 0);
          Prefetch::read(obj->mark_addr(), (HeapWordSize*2));

          // slightly paranoid test; I'm trying to catch potential
          // problems before we go into push_on_queue to know where the
          // problem is coming from
          assert(obj == oopDesc::load_decode_heap_oop(p),
                 "p should still be pointing to obj");
          _par_scan_state->push_on_queue(p);
        } else {
          _par_scan_state->update_rs(_from, p, _par_scan_state->queue_num());
        }
      }
    }