Re: process hangs on do_exit when oom happens

From: Qiang Gao
Date: Tue Oct 23 2012 - 23:44:11 EST


On Wed, Oct 24, 2012 at 1:43 AM, Balbir Singh <bsingharora@xxxxxxxxx> wrote:
> On Tue, Oct 23, 2012 at 3:45 PM, Michal Hocko <mhocko@xxxxxxx> wrote:
>> On Tue 23-10-12 18:10:33, Qiang Gao wrote:
>>> On Tue, Oct 23, 2012 at 5:50 PM, Michal Hocko <mhocko@xxxxxxx> 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/
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