1920     jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);

  1920     jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);

  1921     if (prev == CANCELLABLE) return true;

  1921     if (prev == CANCELLABLE) return true;

  1922     else if (prev == CANCELLED) return false;

  1922     else if (prev == CANCELLED) return false;

  1923     assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers");

  1923     assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers");

  1924     assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED");

  1924     assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED");

  1926       // We need to provide a safepoint here, otherwise we might

  1926       // We need to provide a safepoint here, otherwise we might

  1927       // spin forever if a SP is pending.

  1927       // spin forever if a SP is pending.

  1928       ThreadBlockInVM sp(JavaThread::current());

  1928       ThreadBlockInVM sp(JavaThread::current());

  1929       SpinPause();

  1929       SpinPause();

  1930     }

  1930     }