On Wed, 28 May 2025 at 17:20, Christian König <christian.koe...@amd.com> wrote: > > Hi guys, > > On 5/27/25 01:49, Dave Chinner wrote: > > I disagree - specifically ordered memcg traversal is not something > > that the list_lru implementation is currently doing, nor should it > > be doing. > > I realized over night that I didn't fully explored a way of getting both > advantages. And we actually don't need list_lru for that. > > So here is a side question: > > Is it possible to just have a per cgroup counter on how many pages a cgroup > released back to a particular pool? E.g. something which is added up to the > same counter on the parent when a cgroup is released. > > Background is that the pages are not distinguishable from each other, e.g. > they are not cache hot or cold or anything like this. So it doesn't matter > which pages a cgroup has released but only how many. > > If it would be possible to get such a counter then it would be like just a > few lines of code to add the isolation and still get the advantage of sharing > released pages between different cgroups.
I think numa is the only possible distinction I can see between pages here, even uncached GPU access will be slower to further away numa nodes, But indeed this might be a workable idea, just make something that does what list_lru does but just for the counters, and keep the pages in a single pool. Dave.
