On Mon, Jun 10, 2024 at 6:22 PM James Houghton <jthoughton@xxxxxxxxxx> wrote: > > This new notifier is for multi-gen LRU specifically Let me call it out before others do: we can't be this self-serving. > as it wants to be > able to get and clear age information from secondary MMUs only if it can > be done "fast". > > By having this notifier specifically created for MGLRU, what "fast" > means comes down to what is "fast" enough to improve MGLRU's ability to > reclaim most of the time. > > Signed-off-by: James Houghton <jthoughton@xxxxxxxxxx> If we'd like this to pass other MM reviewers, especially the MMU notifier maintainers, we'd need to design a generic API that can benefit all the *existing* users: idle page tracking [1], DAMON [2] and MGLRU. Also I personally prefer to extend the existing callbacks by adding new parameters, and on top of that, I'd try to consolidate the existing callbacks -- it'd be less of a hard sell if my changes result in less code, not more. (v2 did all these, btw.) [1] https://docs.kernel.org/admin-guide/mm/idle_page_tracking.html [2] https://www.kernel.org/doc/html/latest/mm/damon/index.html