Re: [PATCH mm v2] memcg: notify about global mem_cgroup_id space depletion

[Michal Koutný]

On Mon, Jun 27, 2022 at 06:11:27PM -0700, Roman Gushchin <roman.gushchin@xxxxxxxxx> wrote:
> I think a better approach will be to add a cgroup event (displayed via
> cgroup.events) about reaching the maximum limit of cgroups. E.g.
> cgroups.events::max_nr_reached.

This sounds like a good generalization.

> Then you can set cgroup.max.descendants to some value below memcg_id
> space size. It's more work, but IMO it's a better way to communicate
> this event. As a bonus, you can easily get an idea which cgroup
> depletes the limit.

Just mind there's a difference between events: what cgroup's limit was
hit and what cgroup was affected by the limit [1] (the former is more
useful for the calibration if I understand the situation).

Michal

[1] https://lore.kernel.org/all/20200205134426.10570-2-mkoutny@xxxxxxxx/