linux-kernel - Re: 答复: [PATCH V4] sched/cpufreq: initialize iowait_boost_max and iowait

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Message-ID: <20190304174453.GV32534@hirez.programming.kicks-ass.net>
Date:   Mon, 4 Mar 2019 18:44:53 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Quentin Perret <quentin.perret@....com>
Cc:     Wang, Vincent (王争) 
        <Vincent.Wang@...soc.com>,
        Zhang, Chunyan (张春艳) 
        <Chunyan.Zhang@...soc.com>, Ingo Molnar <mingo@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Chunyan Zhang <zhang.lyra@...il.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>
Subject: Re: 答复: [PATCH V4] sched/cpufreq: initialize iowait_boost_max and
 iowait_boost with cpu capacity

On Mon, Mar 04, 2019 at 06:40:28PM +0100, Peter Zijlstra wrote:

> 	/*
> 	 * @util is already in capacity scale, convert iowait_boost
> 	 * into the same scale so we can compare.
> 	 */
> 	boost = (sg_cpu->iowait_boost * max) >> SCHED_CAPACITY_SHIFT;
> 	util = max(boost, util);
> 	return min(util, max);

Ah, I don't think we need that last min in this case; both terms should
already be <= SCHED_CAPACITY_SCALE.