*** old/src/share/vm/gc/g1/dirtyCardQueue.cpp	Thu Feb 25 12:30:30 2016
--- new/src/share/vm/gc/g1/dirtyCardQueue.cpp	Thu Feb 25 12:30:29 2016

*** 205,238 ****
--- 205,240 ----
  
    return b;
  }
  
  
! BufferNode* DirtyCardQueueSet::get_completed_buffer(int stop_at) {
! BufferNode* DirtyCardQueueSet::get_completed_buffer(size_t stop_at) {
    BufferNode* nd = NULL;
    MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
  
-   if ((int)_n_completed_buffers <= stop_at) {
      _process_completed = false;
      return NULL;
    }
  
    if (_completed_buffers_head != NULL) {
      nd = _completed_buffers_head;
+     assert(_n_completed_buffers > 0, "Invariant");
      _completed_buffers_head = nd->next();
      if (_completed_buffers_head == NULL)
        _completed_buffers_tail = NULL;
      _n_completed_buffers--;
      assert(_n_completed_buffers >= 0, "Invariant");
+     if (_completed_buffers_head == NULL) {
+       assert(_n_completed_buffers == 0, "Invariant");
+       _completed_buffers_tail = NULL;
+     }
    }
    DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
    return nd;
  }
  
  bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl,
                                                            uint worker_i,
!                                                           int stop_at,
!                                                           size_t stop_at,
                                                            bool during_pause) {
    assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause");
    BufferNode* nd = get_completed_buffer(stop_at);
    if (nd == NULL) {
      return false;