Re: [PATCH] mm/oom_kill: wake futex waiters before annihilating victim shared mutex

From: Michal Hocko
Date: Thu Dec 09 2021 - 02:51:58 EST


On Wed 08-12-21 21:59:29, Joel Savitz wrote:
> On Wed, Dec 8, 2021 at 11:05 AM Michal Hocko <mhocko@xxxxxxxx> wrote:
[...]
> > I have had a closer look and I guess I can see what you are trying to
> > achieve. futex_exit_release is normally called from exit_mm context. You
> > are likely seeing a situation when the oom victim is blocked and cannot
> > exit. That is certainly possible but it shouldn't be a permanent state.
> > So I would be more interested about your particular issue and how long
> > the task has been stuck unable to exit.
>
> Before applying this patch I never saw a task eventually exit during
> the reproduction of this system state.

What has happened to the oom victim and why it has never exited?

Side note. I have noticed that you have sent v2 with minor changes. It
is usualy better to resolve review feedback before posting a new
version. Discussion gets rather hard to follow otherwise.

Thanks!
--
Michal Hocko
SUSE Labs