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Message-ID: <e028af69-5583-5378-9573-71e46314687d@arm.com>
Date:   Fri, 29 Sep 2023 09:22:37 +0200
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Subject: Re: [PATCH] cpufreq: Rebuild sched-domains when removing cpufreq
 driver
To:     Viresh Kumar <viresh.kumar@linaro.org>
Cc:     Dietmar Eggemann <dietmar.eggemann@arm.com>,
        linux-kernel@vger.kernel.org,
        Shrikanth Hegde <sshegde@linux.vnet.ibm.com>,
        vschneid@redhat.com, "Rafael J. Wysocki" <rafael@kernel.org>,
        linux-pm@vger.kernel.org
References: <20230918112937.493352-1-pierre.gondois@arm.com>
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 <20230929032743.6mjcyyx3cmjjxsix@vireshk-i7>
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From:   Pierre Gondois <pierre.gondois@arm.com>
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On 9/29/23 05:27, Viresh Kumar wrote:
> On 28-09-23, 14:49, Pierre Gondois wrote:
>> Another solution would be to call sched_cpufreq_governor_change()
>> from cpufreq_schedutil's init()/exit() callbacks. This would make
>> more sense as EAS/schedutil cpufreq are tightly bound, and it would
>> allow to cover all the possible paths.
>>
>> When tried locally, it seems to cover all scenarios:
>> - insmod/rmmod a cpufreq driver
>> - changing the governor policy
>> - offlining all the CPUs of a pd
> 
> Right now it is done for all governors. We don't need that ? We just care about
> schedutil here ?
> 

Yes exact, EAS requires the schedutil governor to be used by all policies. The purpose
of this function is to re-evaluate if EAS enablement conditions are met. I.e., if one
policy changed from/to schedutil, if EAS must be [de|re]activated.