From mboxrd@z Thu Jan  1 00:00:00 1970
From: peterz@infradead.org (Peter Zijlstra)
Date: Tue, 26 Mar 2013 13:50:42 +0100
Subject: [RFC PATCH v3 4/6] sched: secure access to other CPU statistics
In-Reply-To: <1363955155-18382-5-git-send-email-vincent.guittot@linaro.org>
References: <1363955155-18382-1-git-send-email-vincent.guittot@linaro.org>
 <1363955155-18382-5-git-send-email-vincent.guittot@linaro.org>
Message-ID: <1364302242.5053.19.camel@laptop>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Fri, 2013-03-22 at 13:25 +0100, Vincent Guittot wrote:
> @@ -3364,13 +3364,16 @@ done:
>  static bool is_buddy_busy(int cpu)
>  {
>         struct rq *rq = cpu_rq(cpu);
> +       u32 sum = rq->avg.runnable_avg_sum;
> +       u32 period = rq->avg.runnable_avg_period;
> +
> +       sum = min(sum, period);

OK this makes sense; use a simple sanity constraint instead of going
overboard on serialization -- however, why is this a separate patch?

That is, this could easily be part of the patch that introduces
is_buddy_busy(); also you likely want part of this patch's changelog
to become a comment that goes right above this min() :-)