src/hotspot/share/gc/g1/g1FreeIdSet.cpp

*** 77,87 ****
    uint index;
    while (true) {
      index = head_index(old_head);
      assert(index < _size, "invariant");
      uintx new_head = make_head(_next[index], old_head);
!     new_head = Atomic::cmpxchg(new_head, &_head, old_head);
      if (new_head == old_head) break;
      old_head = new_head;
    }
    DEBUG_ONLY(_next[index] = Claimed;)
    return _start + index;
--- 77,87 ----
    uint index;
    while (true) {
      index = head_index(old_head);
      assert(index < _size, "invariant");
      uintx new_head = make_head(_next[index], old_head);
!     new_head = Atomic::cmpxchg(&_head, old_head, new_head);
      if (new_head == old_head) break;
      old_head = new_head;
    }
    DEBUG_ONLY(_next[index] = Claimed;)
    return _start + index;
*** 93,103 ****
    assert(_next[index] == Claimed, "precondition");
    uintx old_head = Atomic::load(&_head);
    while (true) {
      _next[index] = head_index(old_head);
      uintx new_head = make_head(index, old_head);
!     new_head = Atomic::cmpxchg(new_head, &_head, old_head);
      if (new_head == old_head) break;
      old_head = new_head;
    }
    // Now that id has been released, permit another thread through the gate.
    _sem.signal();
--- 93,103 ----
    assert(_next[index] == Claimed, "precondition");
    uintx old_head = Atomic::load(&_head);
    while (true) {
      _next[index] = head_index(old_head);
      uintx new_head = make_head(index, old_head);
!     new_head = Atomic::cmpxchg(&_head, old_head, new_head);
      if (new_head == old_head) break;
      old_head = new_head;
    }
    // Now that id has been released, permit another thread through the gate.
    _sem.signal();