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

Roman Gushchin
2017-10-04T20:22:46Z

On Wed, Oct 04, 2017 at 01:17:14PM -0700, David Rientjes wrote:
> 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?

Sure, no problems.