On Fri, Apr 8, 2022 at 7:55 AM Dan Schatzberg <schatzberg.dan@xxxxxxxxx> wrote: > > On Fri, Apr 08, 2022 at 04:11:05PM +0200, Michal Hocko wrote: > > Regarding "max" as a possible input. I am not really sure to be honest. > > I can imagine that it could be legit to simply reclaim all the charges > > (e.g. before removing the memcg) which should be achieveable by > > reclaiming the reported consumption. Or what exactly should be the > > semantic? > > Yeah, it just allows you to avoid reading memory.current to just > reclaim everything if you can specify "max" - you're still protected > by nretries to eventually bail out. Mostly, though I just feel like > supporting "max" makes memory.reclaim semetric with a lot of the > cgroup memory control files which tend to support "max". One possible approach here is to have force_empty behavior when we write "max" to memory.reclaim. From Google's perspective we don't have a preference, but it seems to me like logical behavior. We can do this either by directly calling mem_cgroup_force_empty() or just draining stock and lrus in memory_reclaim(). This actually brings up another interesting point. Do you think we should drain lrus if try_to_free_mem_cgroup_pages() fails to reclaim the request amount? We can do this after the first call or before the last one. It could introduce more evictable pages for try_to_free_mem_cgroup_pages() to free.
