linux-kernel - Re: [RFC][PATCH v2 2/2] cpufreq: schedutil: Avoid decreasing frequency of busy CPUs

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Message-ID: <20170321170017.tqxcwmtolsqkc4ui@hirez.programming.kicks-ass.net>
Date:   Tue, 21 Mar 2017 18:00:17 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:     Patrick Bellasi <patrick.bellasi@....com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Juri Lelli <juri.lelli@....com>,
        Joel Fernandes <joelaf@...gle.com>,
        Morten Rasmussen <morten.rasmussen@....com>,
        Ingo Molnar <mingo@...hat.com>
Subject: Re: [RFC][PATCH v2 2/2] cpufreq: schedutil: Avoid decreasing
 frequency of busy CPUs

On Tue, Mar 21, 2017 at 04:18:52PM +0100, Rafael J. Wysocki wrote:
> +static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu)
> +{
> +	unsigned long idle_calls = tick_nohz_get_idle_calls();
> +	bool not_idle = idle_calls == sg_cpu->saved_idle_calls;
> +
> +	sg_cpu->saved_idle_calls = idle_calls;
> +	return not_idle && this_rq()->rd->overload;
> +}

So I really don't understand the rd->overload thing. What is it supposed
to do here?