Re: [PATCH] psi: Inherit parent cgroup psi enable state

[Chuyi Zhou <zhouchuyi@bytedance.com>]

Hello Michal,

在 2024/7/29 19:37, Michal Koutný 写道:
> Hello Chuyi.
> 
> On Mon, Jul 29, 2024 at 11:41:00AM GMT, Chuyi Zhou <zhouchuyi@bytedance.com> wrote:
>> This patch tries to solve this issue. When a child cgroup is created, it
>> would inherit the psi enabled state of the parent in group_init().
>> Once the enable state is found to be false in the css_populate_dir(), the
>> {cpu, io, memory}.pressure files will be hidden using cgroup_file_show().
> 
> I'd consider such an inheritance cgroupv1-ism. Notably,
> mmemory.swappiness also had inheritance and it caused some headaches
> because of its susceptibility to races (cgroup creation vs parent
> configuration).

Agree.

> 
> What about adding an option (mount option?) to determine the default of
> per-cgroup pressure accounting?
> (Based on reading about your use case in other mail.) With that you
> could only enable it for the "online" groups of interest.
> 

Yes. We can add a another mount option to disable the default PSI 
accounting and enable the pod we interest.

Thanks.