linux-kernel - Re: [PATCH 0/3] cpufreq: Replace timers with utilization update callbacks

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Message-ID: <20160210123342.GA11415@e106622-lin>
Date:	Wed, 10 Feb 2016 12:33:42 +0000
From:	Juri Lelli <juri.lelli@....com>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	Steve Muckle <steve.muckle@...aro.org>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Linux PM list <linux-pm@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 0/3] cpufreq: Replace timers with utilization update
 callbacks

Hi Rafael,

On 09/02/16 21:05, Rafael J. Wysocki wrote:

[...]

> +/**
> + * cpufreq_update_util - Take a note about CPU utilization changes.
> + * @util: Current utilization.
> + * @max: Utilization ceiling.
> + *
> + * This function is called by the scheduler on every invocation of
> + * update_load_avg() on the CPU whose utilization is being updated.
> + */
> +void cpufreq_update_util(unsigned long util, unsigned long max)
> +{
> +	struct update_util_data *data;
> +
> +	rcu_read_lock();
> +
> +	data = rcu_dereference(*this_cpu_ptr(&cpufreq_update_util_data));
> +	if (data && data->func)
> +		data->func(data, cpu_clock(smp_processor_id()), util, max);

Are util and max used anywhere? It seems to me that cpu_clock is used by
the callbacks to check if the sampling period is elapsed, but I couldn't
yet find who is using util and max.

Thanks,

- Juri