Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <20e4ffb8-905a-92e2-8ea2-6116e8031dac@arm.com>
Date:   Tue, 12 Jul 2022 11:07:06 +0100
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.9.1
Subject: Re: [PATCH] cpufreq: schedutil: Move max CPU capacity to sugov_policy
Content-Language: en-US
To:     Viresh Kumar <viresh.kumar@linaro.org>
Cc:     linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
        rafael@kernel.org, dietmar.eggemann@arm.com,
        vincent.guittot@linaro.org
References: <20220711124229.16516-1-lukasz.luba@arm.com>
 <20220712084137.pb24lolhuk2yln4e@vireshk-i7>
From:   Lukasz Luba <lukasz.luba@arm.com>
In-Reply-To: <20220712084137.pb24lolhuk2yln4e@vireshk-i7>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk


On 7/12/22 09:41, Viresh Kumar wrote:
> On 11-07-22, 13:42, Lukasz Luba wrote:
>> There is no need to keep the max CPU capacity in the per_cpu instance.
>> Furthermore, there is no need to check and update that variable
>> (sg_cpu->max) everytime in the frequency change request, which is part
>> of hot path. Instead use struct sugov_policy to store that information.
>> Initialize the max CPU capacity during the setup and start callback.
>> We can do that since all CPUs in the same frequency domain have the same
>> max capacity (capacity setup and thermal pressure are based on that).
>>
>> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
>> ---
>>   kernel/sched/cpufreq_schedutil.c | 30 +++++++++++++++---------------
>>   1 file changed, 15 insertions(+), 15 deletions(-)
> 
> I tried to check all possible combinations on how this can break, but
> couldn't find one. I had to check that as this code is there since
> ages and none of us thought of it, which was surprising.

I thought the same.

> 
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
> 

Thanks for the ACK!