Re: [RFC PATCH] memcg: use root_mem_cgroup when css is inherited

[Johannes Weiner]

On Thu, Aug 25, 2022 at 06:11:09PM +0800, Zhaoyang Huang wrote:
> Sorry for any misunderstanding among the discussion. My purpose is
> real and simple as I have stated from the very beginning that I would
> like to have per-app cgroup hierarchy to charge memory to root if it
> is not enabled explicitly for memory. The reason has also been stated
> like reclaim and workingset regression in suren's report. I don't
> think my proposal will do any harm to current v2's mechanism besides
> asking for the admin echo "+memory" to their desire group.

It would permit children to escape parental control, completely
breaking the hierarchy and delegation guarantees currently in
place. That just isn't going to happen.

Nacked-by: Johannes Weiner <hannes@xxxxxxxxxxx>

I would suggest focusing on finding the root cause for the reclaim
problem you are describing. It's possible all we need is a fix to
reclaim or the workingset code.