缓存管理策略
“缓存就是存贮数据（使用频繁的数据）的临时地方，因为取原始数据的代价太大了，所以我可以取得快一些。”
in order to manage a cache of information stored on the computer
keeping recent or often-used data items in a memory locations
In computing, cache algorithms (also frequently called cache replacement algorithms or cache replacement policies) are optimizing instructions, or algorithms, that a computer program or a hardware-maintained structure can utilize in order to manage a cache of information stored on the computer. Caching improves performance by keeping recent or often-used data items in a memory locations that are faster or computationally cheaper to access than normal memory stores. When the cache is full, the algorithm must choose which items to discard to make room for the new ones.
https://en.wikipedia.org/wiki/Cache_replacement_policies