On Thu 10-03-22 01:13:50, Wei Yang wrote: > On Wed, Mar 09, 2022 at 02:48:45PM +0100, Michal Hocko wrote: > >[Cc Tim - the patch is http://lkml.kernel.org/r/20220308012047.26638-3-richard.weiyang@xxxxxxxxx] > > > >On Wed 09-03-22 00:46:20, Wei Yang wrote: > >> On Tue, Mar 08, 2022 at 09:17:58AM +0100, Michal Hocko wrote: > >> >On Tue 08-03-22 01:20:47, Wei Yang wrote: > >> >> next_mz is removed from rb_tree, let's add it back if no reclaim has > >> >> been tried. > >> > > >> >Could you elaborate more why we need/want this? > >> > > >> > >> Per my understanding, we add back the right most node even reclaim makes no > >> progress, so it is reasonable to add back a node if we didn't get a chance to > >> do reclaim on it. > > > >Your patch sounded familiar and I can remember now. The same fix has > >been posted by Tim last year > >https://lore.kernel.org/linux-mm/8d35206601ccf0e1fe021d24405b2a0c2f4e052f.1613584277.git.tim.c.chen@xxxxxxxxxxxxxxx/ > >It was posted with other changes to the soft limit code which I didn't > >like but I have acked this particular one. Not sure what has happened > >with it afterwards. > > Because of this ? > 4f09feb8bf: vm-scalability.throughput -4.3% regression > https://lore.kernel.org/linux-mm/20210302062521.GB23892@xsang-OptiPlex-9020/ That was a regression for a different patch in the series AFAICS: : FYI, we noticed a -4.3% regression of vm-scalability.throughput due to commit: : : commit: 4f09feb8bf083be3834080ddf3782aee12a7c3f7 ("mm: Force update of mem cgroup soft limit tree on usage excess") That patch has played with how often memcg_check_events is called and that can lead to a visible performance difference. -- Michal Hocko SUSE Labs
