Re: cpu.stat in core or cpu controller (was Re: [RFC PATCH v2] cgroup: Track time in cgroup v2 freezer)

[Michal Koutný]

On Tue, Jul 22, 2025 at 05:01:50PM +0800, Chen Ridong <chenridong@xxxxxxxxxxxxxxx> wrote:
> Specifically, this change would allow us to:
> 
> 1.Remove these CPU-specific callbacks from the core:
>   css_extra_stat_show()
>   css_local_stat_show()
> 2. Clean up the 'is_self' logic in rstat.c.

If you see an option to organize the code better, why not. (At the same
time, I currently also don't see the "why.)


> 3. Make the stat handling consistent across subsystems (currently cpu.stat is the only
> subsystem-specific stat implemented in the core).

But beware that the possibility of having cpu.stat without enabling the
cpu controller on v2 is a user visible behavior and I'm quite sure some
userspace relies on it, so you'd need to preserve that.

Michal

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