Re: [PATCH] mm,memcg: provide per-cgroup counters for NUMA balancing operations

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 12 Aug 2024 22:49:02 +0000 Kaiyang Zhao <kaiyang2@cs.cmu.edu> wrote:

> On Sun, Aug 11, 2024 at 01:16:53PM -0700, David Rientjes wrote:
> > Hi Kaiyang, have you considered per-memcg control over NUMA balancing 
> > operations as well?
> > 
> > Wondering if that's the direction that you're heading in, because it would 
> > be very useful to be able to control NUMA balancing at memcg granularity 
> > on multi-tenant systems.
> > 
> > I mentioned this at LSF/MM/BPF this year.  If people believe this is out 
> > of scope for memcg, that would be good feedback as well.
> 
> Yes that's exactly where we are heading -- per-cgroup control of NUMA
> balancing operations in the context of memory tiering with CXL memory,
> by extending the concept of memory.low and memory.high. The use case is
> enabling a fair share of top tier memory across containers.
> 
> I'm collaborating with Meta on this, and we already have an implementation
> and some experiments done. The patches will go out soon. If others have 
> thoughts on this, please chime in.

I think it's helpful to capture such broad-brush where-this-is-heading
info in the changelogs.  For reviewers and for posterity.

In fact, any reviewer question should be treated as a bug report
against the changelog!  Questions mean that information was missing.

I'll grab v3 now, but please feel free to send along any changelog
additions which come to mind.