From: Michal Hocko <mhocko@suse.cz>
To: Qiang Gao <gaoqiangscut@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
"cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: process hangs on do_exit when oom happens
Date: Thu, 25 Oct 2012 11:57:19 +0200 [thread overview]
Message-ID: <20121025095719.GA11105@dhcp22.suse.cz> (raw)
In-Reply-To: <CAKWKT+ZahFTnPRJ4FCebxfcrcYEBf+PL9Wa_Foygep_gFst4_g@mail.gmail.com>
On Wed 24-10-12 11:44:17, Qiang Gao wrote:
> On Wed, Oct 24, 2012 at 1:43 AM, Balbir Singh <bsingharora@gmail.com> wrote:
> > On Tue, Oct 23, 2012 at 3:45 PM, Michal Hocko <mhocko@suse.cz> wrote:
> >> On Tue 23-10-12 18:10:33, Qiang Gao wrote:
> >>> On Tue, Oct 23, 2012 at 5:50 PM, Michal Hocko <mhocko@suse.cz> wrote:
> >>> > On Tue 23-10-12 15:18:48, Qiang Gao wrote:
> >>> >> This process was moved to RT-priority queue when global oom-killer
> >>> >> happened to boost the recovery of the system..
> >>> >
> >>> > Who did that? oom killer doesn't boost the priority (scheduling class)
> >>> > AFAIK.
> >>> >
> >>> >> but it wasn't get properily dealt with. I still have no idea why where
> >>> >> the problem is ..
> >>> >
> >>> > Well your configuration says that there is no runtime reserved for the
> >>> > group.
> >>> > Please refer to Documentation/scheduler/sched-rt-group.txt for more
> >>> > information.
> >>> >
> >> [...]
> >>> maybe this is not a upstream-kernel bug. the centos/redhat kernel
> >>> would boost the process to RT prio when the process was selected
> >>> by oom-killer.
> >>
> >> This still looks like your cpu controller is misconfigured. Even if the
> >> task is promoted to be realtime.
> >
> >
> > Precisely! You need to have rt bandwidth enabled for RT tasks to run,
> > as a workaround please give the groups some RT bandwidth and then work
> > out the migration to RT and what should be the defaults on the distro.
> >
> > Balbir
>
>
> see https://patchwork.kernel.org/patch/719411/
The patch surely "fixes" your problem but the primary fault here is the
mis-configured cpu cgroup. If the value for the bandwidth is zero by
default then all realtime processes in the group a screwed. The value
should be set to something more reasonable.
I am not familiar with the cpu controller but it seems that
alloc_rt_sched_group needs some treat. Care to look into it and send a
patch to the cpu controller and cgroup maintainers, please?
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2012-10-25 9:57 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <op.wmbi5kbrn27o5l@gaoqiang-d1.corp.qihoo.net>
2012-10-19 16:04 ` process hangs on do_exit when oom happens Michal Hocko
2012-10-22 2:16 ` Qiang Gao
2012-10-22 5:38 ` Balbir Singh
2012-10-22 13:01 ` Michal Hocko
2012-10-22 4:26 ` Qiang Gao
2012-10-23 3:35 ` Qiang Gao
2012-10-23 4:40 ` Balbir Singh
2012-10-23 7:18 ` Qiang Gao
2012-10-23 9:50 ` Michal Hocko
2012-10-23 10:10 ` Qiang Gao
2012-10-23 10:15 ` Michal Hocko
2012-10-23 17:43 ` Balbir Singh
2012-10-24 3:44 ` Qiang Gao
2012-10-25 9:57 ` Michal Hocko [this message]
2012-10-26 2:42 ` Qiang Gao
2012-10-26 17:03 ` Mike Galbraith
2012-10-26 20:04 ` Mike Galbraith
2012-10-23 8:35 ` Michal Hocko
2012-10-23 9:08 ` Qiang Gao
2012-10-23 9:43 ` Michal Hocko
2012-10-23 9:01 ` Sha Zhengju
2012-10-23 9:10 ` Qiang Gao
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