From: Michal Hocko <mhocko@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: linux-mm@kvack.org,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
David Rientjes <rientjes@google.com>,
Vladimir Davydov <vdavydov@parallels.com>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 10/10] mm, oom: hide mm which is shared with kthread or global init
Date: Thu, 16 Jun 2016 08:31:27 +0200 [thread overview]
Message-ID: <20160616063126.GC30768@dhcp22.suse.cz> (raw)
In-Reply-To: <20160615143701.GA7944@redhat.com>
On Wed 15-06-16 16:37:01, Oleg Nesterov wrote:
> Michal,
>
> I am going to ack the whole series, but send some nits/questions,
>
> On 06/09, Michal Hocko wrote:
> >
> > @@ -283,10 +283,22 @@ enum oom_scan_t oom_scan_process_thread(struct oom_control *oc,
> >
> > /*
> > * This task already has access to memory reserves and is being killed.
> > - * Don't allow any other task to have access to the reserves.
> > + * Don't allow any other task to have access to the reserves unless
> > + * the task has MMF_OOM_REAPED because chances that it would release
> > + * any memory is quite low.
> > */
> > - if (!is_sysrq_oom(oc) && atomic_read(&task->signal->oom_victims))
> > - return OOM_SCAN_ABORT;
> > + if (!is_sysrq_oom(oc) && atomic_read(&task->signal->oom_victims)) {
> > + struct task_struct *p = find_lock_task_mm(task);
> > + enum oom_scan_t ret = OOM_SCAN_ABORT;
> > +
> > + if (p) {
> > + if (test_bit(MMF_OOM_REAPED, &p->mm->flags))
> > + ret = OOM_SCAN_CONTINUE;
> > + task_unlock(p);
>
> OK, but perhaps it would be beter to change oom_badness() to return zero if
> MMF_OOM_REAPED is set?
We already do that:
if (adj == OOM_SCORE_ADJ_MIN ||
test_bit(MMF_OOM_REAPED, &p->mm->flags) ||
in_vfork(p)) {
task_unlock(p);
return 0;
}
It is kind of subtle that we have to check it 2 times but we would have
to rework this code much more because oom_badness only can tell to
ignore the task but not to abort scanning altogether currently. If we
should change this I would suggest a separate patch.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2016-06-16 6:31 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-09 11:52 [PATCH 0/10 -v4] Handle oom bypass more gracefully Michal Hocko
2016-06-09 11:52 ` [PATCH 01/10] proc, oom: drop bogus task_lock and mm check Michal Hocko
2016-06-09 11:52 ` [PATCH 02/10] proc, oom: drop bogus sighand lock Michal Hocko
2016-06-09 11:52 ` [PATCH 03/10] proc, oom_adj: extract oom_score_adj setting into a helper Michal Hocko
2016-06-09 11:52 ` [PATCH 04/10] mm, oom_adj: make sure processes sharing mm have same view of oom_score_adj Michal Hocko
2016-06-15 15:03 ` Oleg Nesterov
2016-06-09 11:52 ` [PATCH 05/10] mm, oom: skip vforked tasks from being selected Michal Hocko
2016-06-15 14:51 ` Oleg Nesterov
2016-06-16 6:24 ` Michal Hocko
2016-06-09 11:52 ` [PATCH 06/10] mm, oom: kill all tasks sharing the mm Michal Hocko
2016-06-09 11:52 ` [PATCH 07/10] mm, oom: fortify task_will_free_mem Michal Hocko
2016-06-09 13:18 ` Tetsuo Handa
2016-06-09 14:20 ` Michal Hocko
2016-06-11 8:10 ` Tetsuo Handa
2016-06-13 11:27 ` Michal Hocko
2016-06-16 12:54 ` Tetsuo Handa
2016-06-16 14:29 ` Michal Hocko
2016-06-16 15:40 ` Tetsuo Handa
2016-06-16 15:53 ` Michal Hocko
2016-06-17 11:38 ` Tetsuo Handa
2016-06-17 12:26 ` Michal Hocko
2016-06-17 13:12 ` Tetsuo Handa
2016-06-17 13:29 ` Michal Hocko
2016-06-09 11:52 ` [PATCH 08/10] mm, oom: task_will_free_mem should skip oom_reaped tasks Michal Hocko
2016-06-17 11:35 ` Tetsuo Handa
2016-06-17 12:56 ` Michal Hocko
2016-06-09 11:52 ` [PATCH 09/10] mm, oom_reaper: do not attempt to reap a task more than twice Michal Hocko
2016-06-15 14:48 ` Oleg Nesterov
2016-06-16 6:28 ` Michal Hocko
2016-06-09 11:52 ` [PATCH 10/10] mm, oom: hide mm which is shared with kthread or global init Michal Hocko
2016-06-09 15:15 ` Tetsuo Handa
2016-06-09 15:41 ` Michal Hocko
2016-06-16 13:15 ` Tetsuo Handa
2016-06-16 13:36 ` Tetsuo Handa
2016-06-15 14:37 ` Oleg Nesterov
2016-06-16 6:31 ` Michal Hocko [this message]
2016-06-13 11:23 ` [PATCH 0/10 -v4] Handle oom bypass more gracefully Michal Hocko
2016-06-13 14:13 ` Michal Hocko
2016-06-14 20:17 ` Oleg Nesterov
2016-06-14 20:44 ` Oleg Nesterov
2016-06-16 6:33 ` Michal Hocko
2016-06-15 15:09 ` Oleg Nesterov
2016-06-16 6:34 ` Michal Hocko
2016-06-20 12:43 [PATCH 0/10 -v5] " Michal Hocko
2016-06-20 12:43 ` [PATCH 10/10] mm, oom: hide mm which is shared with kthread or global init Michal Hocko
2016-07-19 12:05 ` Michal Hocko
2016-07-19 23:27 ` Andrew Morton
2016-07-20 6:29 ` Michal Hocko
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