linux-kernel - Re: [PATCH v3 3/3] oom: decouple mems_allowed from oom_unkillable

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Date:   Wed, 26 Jun 2019 11:18:17 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     Hillf Danton <hdanton@...a.com>
Cc:     Shakeel Butt <shakeelb@...gle.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Vladimir Davydov <vdavydov.dev@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Roman Gushchin <guro@...com>,
        David Rientjes <rientjes@...gle.com>,
        KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
        Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
        Paul Jackson <pj@....com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        syzbot+d0fc9d3c166bc5e4a94b@...kaller.appspotmail.com
Subject: Re: [PATCH v3 3/3] oom: decouple mems_allowed from
 oom_unkillable_task

On Wed 26-06-19 17:12:10, Hillf Danton wrote:
> 
> On Mon, 24 Jun 2019 14:27:11 -0700 (PDT) Shakeel Butt wrote:
> > 
> > @@ -1085,7 +1091,8 @@ bool out_of_memory(struct oom_control *oc)
> >  	check_panic_on_oom(oc, constraint);
> >  
> >  	if (!is_memcg_oom(oc) && sysctl_oom_kill_allocating_task &&
> > -	    current->mm && !oom_unkillable_task(current, oc->nodemask) &&
> > +	    current->mm && !oom_unkillable_task(current) &&
> > +	    has_intersects_mems_allowed(current, oc) &&
> For what?

This is explained in the changelog I believe - see the initial section
about the history and motivation for the check. This patch removes it
from oom_unkillable_task so we have to check it explicitly here.

> >  	    current->signal->oom_score_adj != OOM_SCORE_ADJ_MIN) {
> >  		get_task_struct(current);
> >  		oc->chosen = current;
> > -- 
> > 2.22.0.410.gd8fdbe21b5-goog

-- 
Michal Hocko
SUSE Labs