并发相关

博客：

https://mortoray.com/

重排序：https://mortoray.com/2010/11/18/cpu-reordering-what-is-actually-being-reordered/

双检锁：https://mortoray.com/2012/02/28/double-checked-locking-why-doesnt-it-work-and-how-to-fix-it/