linux-kernel - Re: [PATCH RESEND v4 01/10] PM: EM: Assign a unique ID when creating a performance domain

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Message-ID: <66cbfbbb-53f8-4786-97cf-92eac8daeda8@igalia.com>
Date: Mon, 13 Oct 2025 22:46:23 +0900
From: Changwoo Min <changwoo@...lia.com>
To: Lukasz Luba <lukasz.luba@....com>
Cc: christian.loehle@....com, tj@...nel.org, pavel@...nel.org,
 len.brown@...el.com, rafael@...nel.org, kernel-dev@...lia.com,
 linux-pm@...r.kernel.org, sched-ext@...ts.linux.dev,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH RESEND v4 01/10] PM: EM: Assign a unique ID when creating
 a performance domain

Hi Lukasz,

On 10/6/25 21:24, Lukasz Luba wrote:
> 
> 
> On 10/6/25 09:17, Lukasz Luba wrote:
>> Hi Chanwoo,
>>
>> My apologies to delay on this topic.

Thank you for finding time and making an effort for the review! I
understand that it is not always possible to make time for review. :-)

>>
>> On 9/21/25 04:19, Changwoo Min wrote:
>>> It is necessary to refer to a specific performance domain from a
>>> userspace. For example, the energy model of a particular performance
>>> domain is updated.
>>>
>>> To this end, assign a unique ID to each performance domain to address 
>>> it,
>>
>> Is this related to the sched_ext view on the EM that we cannot re-use
>> the allocated ID for the given domain?
> 
> Ignore that comment, I know the need now.
> 
> Although, there is a small code sneak below...
> 
> 
> 
> [..]
> 
>>> @@ -660,6 +678,13 @@ int em_dev_register_pd_no_update(struct device 
>>> *dev, unsigned int nr_states,
>>>   unlock:
>>>       mutex_unlock(&em_pd_mutex);
>>> +    if (_is_cpu_device(dev))
>>> +        em_check_capacity_update();
>>> +
> 
> It doesn't below to this $subject at all. It looks like
> it was left from some your local changes, isn't it?

You are right. The code is redundant since the same check is done at
em_dev_register_perf_domain(). It is the side-effect of a bad rebase. I
will remove this in the next version.

Regards,
Changwoo Min