Re: [PATCH v2] mm/oom_kill: count global and memory cgroup oom kills

[Konstantin Khlebnikov]

On Tue, May 30, 2017 at 7:29 AM, David Rientjes <rientjes@xxxxxxxxxx> wrote:
> On Thu, 25 May 2017, Konstantin Khlebnikov wrote:
>
>> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
>> index 04c9143a8625..dd30a045ef5b 100644
>> --- a/mm/oom_kill.c
>> +++ b/mm/oom_kill.c
>> @@ -876,6 +876,11 @@ static void oom_kill_process(struct oom_control *oc, const char *message)
>>       /* Get a reference to safely compare mm after task_unlock(victim) */
>>       mm = victim->mm;
>>       mmgrab(mm);
>> +
>> +     /* Raise event before sending signal: reaper must see this */
>
> How is the oom reaper involved here?

Task reaper - OOM event should happens before SIGCHLD.

>
>> +     count_vm_event(OOM_KILL);
>> +     mem_cgroup_count_vm_event(mm, OOM_KILL);
>> +
>>       /*
>>        * We should send SIGKILL before setting TIF_MEMDIE in order to prevent
>>        * the OOM victim from depleting the memory reserves from the user
>
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