Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20210327135600.27836-1-yuehaibing@huawei.com>
In-Reply-To: <20210327135600.27836-1-yuehaibing@huawei.com>
From:   Vincent Guittot <vincent.guittot@linaro.org>
Date:   Mon, 29 Mar 2021 14:35:29 +0200
Message-ID: <CAKfTPtDtfD2B+5AeTYaZCGJZiRtqvnGBdK0Hp4AqC40r5=3=Dw@mail.gmail.com>
Subject: Re: [PATCH -next] sched/fair: Fix unused function warning
To:     YueHaibing <yuehaibing@huawei.com>
Cc:     Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        linux-kernel <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

Hi,

On Sat, 27 Mar 2021 at 14:59, YueHaibing <yuehaibing@huawei.com> wrote:
>
> while CONFIG_NO_HZ_COMMON is not enabled, gcc warn this:
>
> kernel/sched/fair.c:8398:13: warning: =E2=80=98update_nohz_stats=E2=80=99=
 defined but not used [-Wunused-function]
>  static bool update_nohz_stats(struct rq *rq)
>              ^~~~~~~~~~~~~~~~~
>
> Move update_nohz_stats() to #ifdef block fix this.

Could you add a fix tag  ?
Fixes: 0826530de3cb ("sched/fair: Remove update of blocked load from
newidle_balance")

Also could you move update_nohz_stats() closer to its only caller
_nohz_idle_balance()

With these small nits above:

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

>
> Signed-off-by: YueHaibing <yuehaibing@huawei.com>
> ---
>  kernel/sched/fair.c | 40 ++++++++++++++++++----------------------
>  1 file changed, 18 insertions(+), 22 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 6d73bdbb2d40..c7a7ef97d167 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -8395,28 +8395,6 @@ group_type group_classify(unsigned int imbalance_p=
ct,
>         return group_has_spare;
>  }
>
> -static bool update_nohz_stats(struct rq *rq)
> -{
> -#ifdef CONFIG_NO_HZ_COMMON
> -       unsigned int cpu =3D rq->cpu;
> -
> -       if (!rq->has_blocked_load)
> -               return false;
> -
> -       if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask))
> -               return false;
> -
> -       if (!time_after(jiffies, READ_ONCE(rq->last_blocked_load_update_t=
ick)))
> -               return true;
> -
> -       update_blocked_averages(cpu);
> -
> -       return rq->has_blocked_load;
> -#else
> -       return false;
> -#endif
> -}
> -
>  /**
>   * update_sg_lb_stats - Update sched_group's statistics for load balanci=
ng.
>   * @env: The load balancing environment.
> @@ -10097,6 +10075,24 @@ static inline int on_null_domain(struct rq *rq)
>  }
>
>  #ifdef CONFIG_NO_HZ_COMMON
> +static bool update_nohz_stats(struct rq *rq)
> +{
> +       unsigned int cpu =3D rq->cpu;
> +
> +       if (!rq->has_blocked_load)
> +               return false;
> +
> +       if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask))
> +               return false;
> +
> +       if (!time_after(jiffies, READ_ONCE(rq->last_blocked_load_update_t=
ick)))
> +               return true;
> +
> +       update_blocked_averages(cpu);
> +
> +       return rq->has_blocked_load;
> +}
> +
>  /*
>   * idle load balancing details
>   * - When one of the busy CPUs notice that there may be an idle rebalanc=
ing
> --
> 2.17.1
>