Re: [PATCH] mm: add group_oom_kill memory event

[Shakeel Butt <shakeelb@google.com>]

On Fri, Dec 3, 2021 at 8:24 AM Dan Schatzberg <schatzberg.dan@gmail.com> wrote:
>
> Our container agent wants to know when a container exits if it was OOM
> killed or not to report to the user. We use memory.oom.group = 1 to
> ensure that OOM kills within the container's cgroup kill
> everything. Existing memory.events are insufficient for knowing if
> this triggered:
>
> 1) Our current approach reads memory.events oom_kill and reports the
> container was killed if the value is non-zero. This is erroneous in
> some cases where containers create their children cgroups with
> memory.oom.group=1 as such OOM kills will get counted against the
> container cgroup's oom_kill counter despite not actually OOM killing
> the entire container.
>
> 2) Reading memory.events.local will fail to identify OOM kills in leaf
> cgroups (that don't set memory.oom.group) within the container cgroup.
>
> This patch adds a new oom_group_kill event when memory.oom.group
> triggers to allow userspace to cleanly identify when an entire cgroup
> is oom killed.
>
> Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com>

So, with this patch, will you be watching oom_group_kill from
memory.events or memory.events.local file for your use-case?

Reviewed-by: Shakeel Butt <shakeelb@google.com>