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Subject: Re: [Patch v5 5/6] thermal/cpu-cooling: Update thermal pressure in
 case of a maximum frequency capping
To:     Thara Gopinath <thara.gopinath@linaro.org>, mingo@redhat.com,
        peterz@infradead.org, ionela.voinescu@arm.com,
        vincent.guittot@linaro.org, rui.zhang@intel.com,
        edubezval@gmail.com, qperret@google.com
Cc:     linux-kernel@vger.kernel.org, amit.kachhap@gmail.com,
        javi.merino@kernel.org, daniel.lezcano@linaro.org
References: <1572979786-20361-1-git-send-email-thara.gopinath@linaro.org>
 <1572979786-20361-6-git-send-email-thara.gopinath@linaro.org>
From:   Dietmar Eggemann <dietmar.eggemann@arm.com>
Message-ID: <05c53b6f-fd16-3e8b-e8da-ea56325cec33@arm.com>
Date:   Wed, 6 Nov 2019 13:50:29 +0100
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On 05/11/2019 19:49, Thara Gopinath wrote:

[...]

> diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
> index 391f397..c65b7c4 100644
> --- a/drivers/thermal/cpu_cooling.c
> +++ b/drivers/thermal/cpu_cooling.c
> @@ -218,6 +218,27 @@ static u32 cpu_power_to_freq(struct cpufreq_cooling_device *cpufreq_cdev,
>  }
>  
>  /**
> + * update_sched_max_capacity - update scheduler about change in cpu
> + *				max frequency.
> + * @cpus: list of cpus whose max capacity needs udating in scheduler.
> + * @cur_max_freq: current maximum frequency.
> + * @max_freq: highest possible frequency.
> + */
> +static void update_sched_max_capacity(struct cpumask *cpus,
> +				      unsigned int cur_max_freq,
> +				      unsigned int max_freq)
> +{
> +	int cpu;
> +	unsigned long capacity;
> +
> +	for_each_cpu(cpu, cpus) {
> +		capacity = cur_max_freq * arch_scale_cpu_capacity(cpu);
> +		capacity /= max_freq;
> +		update_thermal_pressure(cpu, capacity);
> +	}
> +}
> +
> +/**

Have you seen
https://lore.kernel.org/r/2b19d7da-412c-932f-7251-110eadbef3e3@arm.com ?

Also the naming 'update_thermal_pressure()' is not really suitable for
an external task scheduler interface. If I see this called in the
cooling device code, I wouldn't guess that this is a task scheduler
interface.

[...]