A problem encountered in actual use. I'm going to get a -k shutdown.
Then read squid 's access log, found that the files that were originally cached are just tcp hits, and any frequent access can't be loaded into the tcp mem hit.
If it was originally no cached file, new access asks, the first miss, the second is tcp mem hit memory hit.
The replacement strategy uses the default lru, which isn't clear what the internal mechanism is exchanged between the memory and disk.