linux-kernel - Re: [PATCH V2 9/9] cpufreq: scmi: Use .register

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Message-ID: <143a03df-d858-b2de-a2cc-983c35d71e53@arm.com>
Date:   Wed, 11 Aug 2021 17:32:09 +0100
From:   Lukasz Luba <lukasz.luba@....com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Rafael Wysocki <rjw@...ysocki.net>,
        Sudeep Holla <sudeep.holla@....com>,
        Cristian Marussi <cristian.marussi@....com>,
        linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Quentin Perret <qperret@...gle.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2 9/9] cpufreq: scmi: Use .register_em() callback



On 8/11/21 12:58 PM, Viresh Kumar wrote:
> Set the newly added .register_em() callback to register with the EM
> after the cpufreq policy is properly initialized.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
>   drivers/cpufreq/scmi-cpufreq.c | 55 ++++++++++++++++++++--------------
>   1 file changed, 32 insertions(+), 23 deletions(-)

>   
> +static void scmi_cpufreq_register_em(struct cpufreq_policy *policy)
> +{
> +	struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power);
> +	bool power_scale_mw = perf_ops->power_scale_mw_get(ph);
> +	struct scmi_data *priv = policy->driver_data;
> +
> +	em_dev_register_perf_domain(get_cpu_device(policy->cpu), priv->nr_opp,
> +				    &em_cb, priv->opp_shared_cpus,
> +				    power_scale_mw);

I would free the priv->opp_shared_cpus mask here, since we don't
need it anymore and memory can be reclaimed. Don't forget this
setup would be called N CPUs times, on this per-CPU policy platform.

If freed here, then also there wouldn't be a need to free it in
scmi_cpufreq_exit() so you can remove it from there.

> +}
> +
>   static struct cpufreq_driver scmi_cpufreq_driver = {
>   	.name	= "scmi",
>   	.flags	= CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
> @@ -261,6 +269,7 @@ static struct cpufreq_driver scmi_cpufreq_driver = {
>   	.get	= scmi_cpufreq_get_rate,
>   	.init	= scmi_cpufreq_init,
>   	.exit	= scmi_cpufreq_exit,
> +	.register_em	= scmi_cpufreq_register_em,
>   };
>   
>   static int scmi_cpufreq_probe(struct scmi_device *sdev)
> 

I will test&review this patch on Monday when I re-flash custom FW to my
Juno (just to be sure that this per-CPU cpufreq + shared EM/EAS works).