On Sat, 2012-10-20 at 21:06 +0200, Andrea Righi wrote:
> @@ -383,13 +383,7 @@ struct rq {
> struct list_head leaf_rt_rq_list;
> #endif
>
> + unsigned long __percpu *nr_uninterruptible;
This is O(nr_cpus^2) memory..
> +unsigned long nr_uninterruptible_cpu(int cpu)
> +{
> + struct rq *this = cpu_rq(cpu);
> + unsigned long val = 0;
> + int i;
> +
> + for_each_online_cpu(i)
> + val += per_cpu(*this->nr_uninterruptible, i);
> +
> + return val;
> +}
>
>
I suspect you've got an accounting leak here on hot-plug.
>
> unsigned long nr_uninterruptible(void)
> {
> unsigned long i, sum = 0;
>
> for_each_possible_cpu(i)
> - sum += cpu_rq(i)->nr_uninterruptible;
> + sum += nr_uninterruptible_cpu(i);
>
> /*
> * Since we read the counters lockless, it might be slightly
And this makes O(n^2) runtime!
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