tbh this was my thought too. No need for background processing either, there are quite a few options for amortized-constant-time old-value deletion at lookup t

tbh this was my thought too. No need for background processing either, there are quite a few options for amortized-constant-time old-value deletion at lookup time. Or do that cleanup while checking the disk on a cache miss - if you have no misses, the cache is working fantastically and probably shouldn't be pruned. Or is there some reason those aren't acceptable in-kernel, while apparently a lack of cleanup is fine? Maybe CPU use is too high...?