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Date:   Mon, 3 Jul 2023 17:22:48 +0100
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Subject: Re: [PATCH v2 03/17] PM: EM: Refactor em_pd_get_efficient_state() to
 be more flexible
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To:     Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc:     rui.zhang@intel.com, amit.kucheria@verdurent.com,
        amit.kachhap@gmail.com, daniel.lezcano@linaro.org,
        viresh.kumar@linaro.org, len.brown@intel.com, pavel@ucw.cz,
        Pierre.Gondois@arm.com, ionela.voinescu@arm.com,
        rostedt@goodmis.org, mhiramat@kernel.org,
        linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
        rafael@kernel.org
References: <20230512095743.3393563-1-lukasz.luba@arm.com>
 <20230512095743.3393563-4-lukasz.luba@arm.com>
 <418bef75-883c-2442-3376-03fd7537c734@arm.com>
From:   Lukasz Luba <lukasz.luba@arm.com>
In-Reply-To: <418bef75-883c-2442-3376-03fd7537c734@arm.com>
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On 5/30/23 12:06, Dietmar Eggemann wrote:
> On 12/05/2023 11:57, Lukasz Luba wrote:
>> Prepare em_pd_get_efficient_state() for the upcoming changes and
>> make it possible to re-use. Return an index for the best performance
> 
> Don't get the `possible to re-use`? Did you mean `possible to be
> re-used`? But then `re-used` for what?

The function will no longer get a pointer to 'struct em_perf_domain'
but instead to 'struct em_perf_state'. It would also require to
get the number of states from 'pd->nr_perf_states'.

This is preparation for handling 2 tables:
modifiable (a) and default (b).

Then it also returns and ID not the pointer to state.
It all makes it more generic and ready for those 2 tables.

> 
>> state. The function arguments that are introduced should allow to
>> work on different performance state arrays. The caller of
>> em_pd_get_efficient_state() should be able to use the index either
>> on the default or the modifiable EM table.
> 
> This describes the WHAT but not the WHY.

I will add that description as 'why' in the header. I wanted to
avoid mentioning in the patch description something which
is coming in the next patch.