while spin locks are cpu-intensive and appear inefficient, they can be more efficient than suspending the thread and subsequently waking it up if the lock in question is held for a very short time.
虽然旋转锁是cpu密集型的,显得效率低下,但是如果争夺的锁被持有的时间非常短,那么旋转锁要比暂挂线程然后再唤醒它更有效率。