linux-kernel - Re: [PATCH v4 04/18] PM: EM: Refactor em_pd_get_efficient

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Message-ID: <b68e15d1-87b0-4a60-8f09-3d8856c16919@arm.com>
Date:   Tue, 24 Oct 2023 09:09:50 +0100
From:   Lukasz Luba <lukasz.luba@....com>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     dietmar.eggemann@....com, rui.zhang@...el.com,
        amit.kucheria@...durent.com, amit.kachhap@...il.com,
        viresh.kumar@...aro.org, len.brown@...el.com, pavel@....cz,
        mhiramat@...nel.org, qyousef@...alina.io, wvw@...gle.com,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        rafael@...nel.org
Subject: Re: [PATCH v4 04/18] PM: EM: Refactor em_pd_get_efficient_state() to
 be more flexible



On 10/23/23 18:39, Daniel Lezcano wrote:
> On 25/09/2023 10:11, Lukasz Luba wrote:
>> The Energy Model (EM) is going to support runtime modification. There
>> are going to be 2 EM tables which store information. This patch aims
>> to prepare the code to be generic and use one of the tables. The function
>> will no longer get a pointer to 'struct em_perf_domain' (the EM) but
>> instead a pointer to 'struct em_perf_state' (which is one of the EM's
>> tables).
>>
>> Prepare em_pd_get_efficient_state() for the upcoming changes and
>> make it possible to re-use. Return an index for the best performance
>> state for a given EM table. 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.
>>
>> Signed-off-by: Lukasz Luba <lukasz.luba@....com>
>> ---
> 
> [ ... ]
> 
>> @@ -251,7 +253,9 @@ static inline unsigned long em_cpu_energy(struct 
>> em_perf_domain *pd,
>>        * Find the lowest performance state of the Energy Model above the
>>        * requested frequency.
>>        */
>> -    ps = em_pd_get_efficient_state(pd, freq);
>> +    i = em_pd_get_efficient_state(pd->table, pd->nr_perf_states, freq,
>> +                      pd->flags);
> 
> nitpicking but s/i/state/

Here it makes sense, I'll try to use 'state', but if that could be a bit
odd in later patches code, where I have:

ps = &runtime_table->state[i];

than:

'->state[state]'

won't fly. Although, let me check, because I'm going to drop the
2 tables design so some fields might get different names.

> 
> Other than that:
> 
> Reviewed-by: Daniel Lezcano <daniel.lezcano@...aro.org>

Thanks!

> 
> 
>> +    ps = &pd->table[i];
>>       /*
>>        * The capacity of a CPU in the domain at the performance state 
>> (ps)
>