if (!Plan.gcInProgress()) addToCommitted(pages);
  public boolean acquire (int pages) {    lock();    reserved = committed + pages;    if (reserved > pageBudget) {      unlock();   // We cannot hold the lock across a GC point!      if (VM_Interface.getPlan().poll(false, this)) {	return false;      }      lock();    }    committed += pages;    unlock();    return true;  }