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

[Chen Ridong]

On 2025/7/22 19:54, Michal Koutný wrote:
> 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.
> 

This is what I worry about. Thank you for your confirmation.

Best regards,
Ridong