Re: [RFC PATCH v3 4/6] sched: secure access to other CPU statistics

From: Peter Zijlstra
Date: Tue Mar 26 2013 - 08:50:51 EST


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() :-)

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