linux-kernel - Re: [PATCH v7 02/15] sched/core: uclamp: Enforce last task UCLAMP

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Message-ID: <20190313141008.GF5922@hirez.programming.kicks-ass.net>
Date:   Wed, 13 Mar 2019 15:10:08 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Patrick Bellasi <patrick.bellasi@....com>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-api@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
        Tejun Heo <tj@...nel.org>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Paul Turner <pjt@...gle.com>,
        Quentin Perret <quentin.perret@....com>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Morten Rasmussen <morten.rasmussen@....com>,
        Juri Lelli <juri.lelli@...hat.com>,
        Todd Kjos <tkjos@...gle.com>,
        Joel Fernandes <joelaf@...gle.com>,
        Steve Muckle <smuckle@...gle.com>,
        Suren Baghdasaryan <surenb@...gle.com>
Subject: Re: [PATCH v7 02/15] sched/core: uclamp: Enforce last task UCLAMP_MAX

On Fri, Feb 08, 2019 at 10:05:41AM +0000, Patrick Bellasi wrote:
> +uclamp_idle_value(struct rq *rq, unsigned int clamp_id, unsigned int clamp_value)
> +{
> +	/*
> +	 * Avoid blocked utilization pushing up the frequency when we go
> +	 * idle (which drops the max-clamp) by retaining the last known
> +	 * max-clamp.
> +	 */
> +	if (clamp_id == UCLAMP_MAX) {
> +		rq->uclamp_flags |= UCLAMP_FLAG_IDLE;
> +		return clamp_value;
> +	}
> +
> +	return uclamp_none(UCLAMP_MIN);

That's a very complicated way or writing: return 0, right?

> +}