Re: [PATCH RFC] fs: drop_caches: introduce per-node drop_caches interface

Lorenzo Stoakes
2026-04-09T08:27:49Z

On Thu, Apr 09, 2026 at 04:21:43PM +0800, Kefeng Wang wrote:
> Our use case is as follows, for hot-pluggable nodes, for anon pages,
> migrating them to other nodes, but for pagecaches, just evicting them
> since pages could be refaulted. For mem-tiering, a large amount of cold
> memory is stored in the low tier, we think that evicting pagecache is
> better than migrating them back to high tier, also this avoid the risk
> of accessing potentially faulty memory.

Hmm, this feels like it should be a heuristic in mm rather than something people
are manually triggering by writing to a file?

I'm not sure I'm OK with us allowing people to manipulate core mm page cache
state for non-debug/synthetic perf analysis reasons.

Cheers, Lorenzo