Re: [PATCH] mm: mempolicy: don't select exited threads as OOM victims

[Michal Hocko <mhocko@kernel.org>]

On Wed 03-07-19 06:26:55, Tetsuo Handa wrote:
> On 2019/07/02 22:51, Michal Hocko wrote:
> >>> I do not see any strong reason to keep the current ordering. OOM victim
> >>> check is trivial so it shouldn't add a visible overhead for few
> >>> unkillable tasks that we might encounter.
> >>>
> >>
> >> Yes if we can tolerate that there can be only one OOM victim for !memcg OOM events
> >> (because an OOM victim in a different OOM context will hit "goto abort;" path).
> > 
> > You are right. Considering that we now have a guarantee of a forward
> > progress then this should be tolerateable (a victim in a disjoint
> > numaset will go away and other one can go ahead and trigger its own
> > OOM).
> 
> But it might take very long period before MMF_OOM_SKIP is set by the OOM reaper
> or exit_mmap(). Until MMF_OOM_SKIP is set, OOM events from disjoint numaset can't
> make forward progress.

If that is a concern then I would stick with the current status quo
until we see the issue to be reported by real workloads.

-- 
Michal Hocko
SUSE Labs