Re: [PATCH v2 09/10] sched/psi: per-cgroup PSI stats disable/re-enable interface
From: Michal Koutný
Date: Fri Aug 12 2022 - 06:15:55 EST
Hello Chengming.
On Mon, Aug 08, 2022 at 07:03:40PM +0800, Chengming Zhou <zhouchengming@xxxxxxxxxxxxx> wrote:
> diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
> index dd84e34bc051..ade40506ab80 100644
> --- a/Documentation/admin-guide/cgroup-v2.rst
> +++ b/Documentation/admin-guide/cgroup-v2.rst
> @@ -968,6 +968,13 @@ All cgroup core files are prefixed with "cgroup."
> killing cgroups is a process directed operation, i.e. it affects
> the whole thread-group.
>
> + cgroup.psi
> + A read-write single value file that allowed values are "0" and "1".
> + The default is "1".
> +
> + Writing "0" to the file will disable the cgroup PSI stats accounting.
> + Writing "1" to the file will re-enable the cgroup PSI stats accounting.
> +
I'd suggest explaining here explicitely, this control attribute is not
hierarchical (i.e. PSI accounting in a cgroup does not affect accounting
in descendants and doesn't need pass enablement via ancestors from
root). And the purpose that it "saves" cycles (where).
Regards,
Michal