Re: [v10 3/6] mm, oom: cgroup-aware OOM killer

David Rientjes
2017-10-04T20:17:18Z

On Wed, 4 Oct 2017, Roman Gushchin wrote:

> > > @@ -828,6 +828,12 @@ static void __oom_kill_process(struct task_struct *victim)
> > > struct mm_struct *mm;
> > > bool can_oom_reap = true;
> > >
> > > + if (is_global_init(victim) || (victim->flags & PF_KTHREAD) ||
> > > + victim->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) {
> > > + put_task_struct(victim);
> > > + return;
> > > + }
> > > +
> > > p = find_lock_task_mm(victim);
> > > if (!p) {
> > > put_task_struct(victim);
> >
> > Is this necessary? The callers of this function use oom_badness() to
> > find a victim, and that filters init, kthread, OOM_SCORE_ADJ_MIN.
>
> It is. __oom_kill_process() is used to kill all processes belonging
> to the selected memory cgroup, so we should perform these checks
> to avoid killing unkillable processes.
>

That's only true after the next patch in the series which uses the
oom_kill_memcg_member() callback to kill processes for oom_group, correct?
Would it be possible to move this check to that patch so it's more
obvious?