Re: [PATCH v5] memcg: expose socket memory pressure in a cgroup

[Tejun Heo <tj@kernel.org>]

On Tue, Oct 07, 2025 at 02:50:56PM +0200, Daniel Sedlak wrote:
...
> 1) None - keeping the reported duration local to that cgroup:
> 2) Propagating the duration upwards (using rstat or simple iteration
> 3) Propagating the duration downwards (write only locally,
>    read traversing hierarchy upwards):
...
> We chose variant 1, that is why it is a separate file instead of another
> counter in mem.stat. Variant 2 seems to be most fitting however the
> calculated value would be misleading and hard to interpret. Ideally, we
> would go with variant 3 as this mirrors the logic of
> mem_cgroup_under_socket_pressure(), but the third variant can be also
> calculated manually from variant 1, and thus we chose the variant 1
> as it is the most versatile one without leaking the internal
> implementation that can change in the future.

I'm not against going 1) but let's not do a separate file for this. Can't
you do memory.stat.local? It'd be better to have aggregation in memory.stat
but we can worry about that later.

Thanks.

-- 
tejun