redis内存淘汰策略
LRU: https://javap.blog.csdn.net/article/details/133889335
LFU: https://blog.csdn.net/qq_32099833/article/details/133889357
LRU: https://javap.blog.csdn.net/article/details/133889335
LFU: https://blog.csdn.net/qq_32099833/article/details/133889357