On Mon, Jan 22, 2024 at 7:20 AM Michal Koutný <mkoutny@xxxxxxxx> wrote:
>
> Hello.
>
> On Thu, Jan 18, 2024 at 06:42:35PM +0000, Shakeel Butt <shakeelb@xxxxxxxxxx> wrote:
> > One of our workloads (Postgres 14) has regressed when migrated from 5.10
> > to 6.1 upstream kernel. The regression can be reproduced by sysbench's
> > oltp_write_only benchmark.
> > It seems like the always on rstat flush in
> > mem_cgroup_wb_stats() is causing the regression.
>
> Is the affected benchmark running in a non-root cgroup?
>
> I'm asking whether this would warrant a
> Fixes: fd25a9e0e23b ("memcg: unify memcg stat flushing")
> that introduced the global flush (in v6.1) but it was removed later in
> 7d7ef0a4686a ("mm: memcg: restore subtree stats flushing")
> (so v6.8 could be possibly unaffected).
>
Yes, the benchmark and the workload were running in non-root cgroups.
Regarding the Fixes, please note that the regression was still there
with 7d7ef0a4686a ("mm: memcg: restore subtree stats flushing"), so I
would say that our first conversion to rstat infra would most probably
have the issue as well which was 2d146aa3aa84 ("mm: memcontrol: switch
to rstat").
So, the following fixes tag makes sense to me:
Fixes: 2d146aa3aa84 ("mm: memcontrol: switch to rstat")
