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

[David Rientjes <rientjes@google.com>]

On Mon, 12 Aug 2024, Kaiyang Zhao 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.
> 

Thanks Kaiyang, that will be very useful to test out, looking forward to 
seeing the patches!

Does this include top-tier specific memory limits as well?

And is your primary motivation the promotion path through NUMA Balancing 
or are you also looking at demotion to develop a comprehensive policy for 
memory placement using these limits?

> 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 have lots of thoughts, but not sure if the primary motivation is around 
promotion only here :)