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From: Vincent Guittot <vincent.guittot@linaro.org>
Date: Fri, 25 Aug 2017 15:40:15 +0200
Message-ID: <CAKfTPtC=uU_tRVmLXRx9bfUOED6c_V6XRdDc_1Gw+mRcwQbiAg@mail.gmail.com>
Subject: Re: [PATCH v2 2/5] sched/fair: Remove unnecessary comparison with -1
To: Brendan Jackman <brendan.jackman@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>, Peter Zijlstra <peterz@infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Joel Fernandes <joelaf@google.com>,
        Andres Oportus <andresoportus@google.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Josef Bacik <josef@toxicpanda.com>,
        Morten Rasmussen <morten.rasmussen@arm.com>
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On 25 August 2017 at 12:16, Brendan Jackman <brendan.jackman@arm.com> wrote:
> Since commit 83a0a96a5f26 ("sched/fair: Leverage the idle state info
> when choosing the "idlest" cpu") find_idlest_grou_cpu (formerly
> find_idlest_cpu) no longer returns -1.
>
> Signed-off-by: Brendan Jackman <brendan.jackman@arm.com>
> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
> Cc: Vincent Guittot <vincent.guittot@linaro.org>
> Cc: Josef Bacik <josef@toxicpanda.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Morten Rasmussen <morten.rasmussen@arm.com>
> Cc: Peter Zijlstra <peterz@infradead.org>

Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>

> ---
>  kernel/sched/fair.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index f6e277c65235..4ccecbf825bf 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -5583,7 +5583,7 @@ static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p
>                 }
>
>                 new_cpu = find_idlest_group_cpu(group, p, cpu);
> -               if (new_cpu == -1 || new_cpu == cpu) {
> +               if (new_cpu == cpu) {
>                         /* Now try balancing at a lower domain level of cpu */
>                         sd = sd->child;
>                         continue;
> --
> 2.14.1
>