Re: [PATCH] mm: change memcg->oom_group access with atomic operations

Roman Gushchin
2023-02-20T21:09:56Z

On Mon, Feb 20, 2023 at 11:16:38PM +0800, Yue Zhao wrote:
> The knob for cgroup v2 memory controller: memory.oom.group
> will be read and written simultaneously by user space
> programs, thus we'd better change memcg->oom_group access
> with atomic operations to avoid concurrency problems.
>
> Signed-off-by: Yue Zhao <findns94@gmail.com>

Hi Yue!

I'm curious, have any seen any real issues which your patch is solving?
Can you, please, provide a bit more details.

Also, WRITE/READ_ONCE() don't generally make operations atomic,
they only prevent the compiler from merging and re-fetching reads
and writes.

Thanks!