Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Wed, 13 Mar 2019 18:22:25 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Patrick Bellasi <patrick.bellasi@arm.com>
Cc:     linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
        linux-api@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
        Tejun Heo <tj@kernel.org>,
        "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Paul Turner <pjt@google.com>,
        Quentin Perret <quentin.perret@arm.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Morten Rasmussen <morten.rasmussen@arm.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Todd Kjos <tkjos@google.com>,
        Joel Fernandes <joelaf@google.com>,
        Steve Muckle <smuckle@google.com>,
        Suren Baghdasaryan <surenb@google.com>
Subject: Re: [PATCH v7 01/15] sched/core: uclamp: Add CPU's clamp buckets
 refcounting
Message-ID: <20190313172225.GG5996@hirez.programming.kicks-ass.net>
References: <20190208100554.32196-1-patrick.bellasi@arm.com>
 <20190208100554.32196-2-patrick.bellasi@arm.com>
 <20190313134022.GB5922@hirez.programming.kicks-ass.net>
 <20190313161229.pkib2tmjass5chtb@e110439-lin>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20190313161229.pkib2tmjass5chtb@e110439-lin>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Mar 13, 2019 at 04:12:29PM +0000, Patrick Bellasi wrote:
> Yes, the for looks better, but perhaps like that:
> 
> 	unsigned int bucket_id = UCLAMP_BUCKETS;
> 
>  	/*
>  	 * Both min and max clamps are MAX aggregated, thus the topmost
>  	 * bucket with some tasks defines the rq's clamp value.
>  	 */
> 	for (; bucket_id >= 0; --bucket_id) {

GCC will be clever and figure that unsigned will never be smaller than 0
and turn the above into an infinite loop or something daft.

That is; use 'int', not 'unsigned int' for bucket_id.