Re: [PATCH v4] memcg: expose socket memory pressure in a cgroup

[Tejun Heo <tj@kernel.org>]

Hello,

On Wed, Aug 13, 2025 at 02:03:28PM +0200, Michal Koutný wrote:
...
> One more point to clarify -- should the value include throttling from
> ancestors or not. (I think both are fine but) this semantic should also
> be described in the docs. I.e. current proposal is
> 	value = sum_children + self
> and if you're see that C's value is 0, it doesn't mean its sockets
> weren't subject of throttling. It just means you need to check also
> values in C ancestors. Does that work?

I was more thinking that it would account for all throttled durations, but
it's true that we only count locally originating events for e.g.
memory.events::low or pids.events::max. Hmm... I'm unsure. So, for events, I
think local sources make sense as it's tracking what limits are triggering
where. However, I'm not sure that translates well to throttle duration which
is closer to pressure metrics than event counters. We don't distinguish the
sources of contention when presenting pressure metrics after all.

Thanks.

-- 
tejun