Re: [PATCH] Add the memcg print oom info for system oom

[禹舟键 <ufo19890607@gmail.com>]

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Hi Michal
I think the current OOM report is imcomplete. I can get the task which
invoked the oom-killer and the task which has been killed by the
oom-killer, and memory info when the oom happened. But I cannot infer the
certain memcg to which the task killed by oom-killer belongs, because that
task has been killed, and the dump_task will print all of the tasks in the
system.

mem_cgroup_print_oom_info will print five lines of content including
memcg's name , usage, limit. I don't think five lines of content will cause
a big problem. Or it at least prints the memcg's name.

Thanks
Wind

Michal Hocko <mhocko@kernel.org> 于2018年5月17日周四 下午3:11写道：

> On Thu 17-05-18 08:00:28, ufo19890607 wrote:
> > From: yuzhoujian <yuzhoujian@didichuxing.com>
> >
> > The dump_header does not print the memcg's name when the system
> > oom happened. Some users want to locate the certain container
> > which contains the task that has been killed by the oom killer.
> > So I add the mem_cgroup_print_oom_info when system oom events
> > happened.
>
> The oom report is quite heavy today. Do we really need the full memcg
> oom report here. Wouldn't it be sufficient to print the memcg the task
> belongs to?
>
> > Signed-off-by: yuzhoujian <yuzhoujian@didichuxing.com>
> > ---
> >  mm/oom_kill.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> > index 8ba6cb88cf58..244416c9834a 100644
> > --- a/mm/oom_kill.c
> > +++ b/mm/oom_kill.c
> > @@ -433,6 +433,7 @@ static void dump_header(struct oom_control *oc,
> struct task_struct *p)
> >       if (is_memcg_oom(oc))
> >               mem_cgroup_print_oom_info(oc->memcg, p);
> >       else {
> > +             mem_cgroup_print_oom_info(mem_cgroup_from_task(p), p);
> >               show_mem(SHOW_MEM_FILTER_NODES, oc->nodemask);
> >               if (is_dump_unreclaim_slabs())
> >                       dump_unreclaimable_slab();
> > --
> > 2.14.1
> >
>
> --
> Michal Hocko
> SUSE Labs
>

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