FROM 硬件内存模型：

threads in the system must agree about a total order for the writes to a single memory location. That is, threads must agree which writes overwrite other writes. This property is called called coherence.

内存一致性的系统都所有线程都必须接受对一个内存地址所有写入的总顺序。换句话说，所有线程必须同意哪些写入可以覆盖另外的一些写入。