public boolean poll(boolean mustCollect, MemoryResource mr)
final public boolean poll(boolean mustCollect, MemoryResource mr)
  public boolean poll(boolean mustCollect, MemoryResource mr)    throws VM_PragmaLogicallyUninterruptible {    if (gcInProgress) return false;    if (mustCollect || getPagesReserved() > getTotalPages()) {      if (VM.VerifyAssertions) VM._assert(mr != metaDataMR);      required = mr.reservedPages() - mr.committedPages();      if (mr == nurseryMR)	required = required<<1;  // must account for copy reserve      VM_Interface.triggerCollection();      return true;    }    return false;  }