Cache expiration policy (the difference between FIFO, LRU, LFU three algorithms) __ Cache

When the cache needs to be cleaned up (for example, the space occupancy is close to the critical value), some sort of elimination algorithm is needed to decide which data to clean out. Commonly used elimination algorithms have the following: Fifo:first in the first out, FIFO. Judged by the time stored, from the current farthest data priority is eliminated. Lru:least recently Used, least recently used. To determine the most recent time used, the current farthest data priority is eliminated. Lfu:least frequently Used, most infrequently used. In a period of time, the data is used the least number of times, priority is eliminated.