Re: [PATCH v2 2/2] cgroup/cpuset: Rebind/migrate mm only for threadgroup leader in cpuset_update_tasks_nodemask()

From: Manuel Ebner

Date: Wed Jun 24 2026 - 04:27:56 EST


Hi

On Tue, 2026-06-23 at 19:04 -0400, Waiman Long wrote:
> [...]
> Also add a paragraph in cgroup-v2.rst under cpuset.mems that the
> threadgroup leader is the memory owner of that threadgroup. Therefore
> the non-leading threads shouldn't be in other cgroups whose "cpuset.mems"
> doesn't fully overlap that of the group leader.

This sentence is long and complex, split into two if possible. I couldn't
figure out how to do so.

> [...]
> --- a/Documentation/admin-guide/cgroup-v2.rst
> +++ b/Documentation/admin-guide/cgroup-v2.rst
> @@ -2527,6 +2527,13 @@ Cpuset Interface Files
>   a need to change "cpuset.mems" with active tasks, it shouldn't
>   be done frequently.
>  
> + For a multithreaded process, the threadgroup leader is
> + considered the owner of the group's memory. Memory policy
> + rebinding and migration will only happen with respect to the
> + threadgroup leader. To avoid unexpected result, non-leading

/result/results/
or
To avoid an unexpected result,

> + threads shouldn't be put into another cgroup whose "cpuset.mems"
> + doesn't fully overlap that of the threadgroup leader.

maybe
/threadgroup/threadgroups/


Thanks
Manuel