From:   Benjamin Segall <bsegall@google.com>
To:     Li kunyu <kunyu@nfschina.com>
Cc:     mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
        vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
        rostedt@goodmis.org, mgorman@suse.de, bristot@redhat.com,
        vschneid@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sched: core: Optimize the structure of
 'tg_cfs_schedulable_down' function
References: <20230319200255.3640-1-kunyu@nfschina.com>
Date:   Mon, 20 Mar 2023 15:48:36 -0700
In-Reply-To: <20230319200255.3640-1-kunyu@nfschina.com> (Li kunyu's message of
        "Mon, 20 Mar 2023 04:02:55 +0800")
Message-ID: <xm26o7onvy2j.fsf@google.com>
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Li kunyu <kunyu@nfschina.com> writes:

> Optimize if branches and define  in the branch statement
> block=E3=80=80parent_quota variable.

It's not an optimization; it is arguably a slight style improvement.

>
> Signed-off-by: Li kunyu <kunyu@nfschina.com>
> ---
>  kernel/sched/core.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 488655f2319f..7e8535d2e36d 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -10915,15 +10915,12 @@ static int tg_cfs_schedulable_down(struct task_=
group *tg, void *data)
>  {
>  	struct cfs_schedulable_data *d =3D data;
>  	struct cfs_bandwidth *cfs_b =3D &tg->cfs_bandwidth;
> -	s64 quota =3D 0, parent_quota =3D -1;
> +	s64 quota =3D RUNTIME_INF;
>=20=20
> -	if (!tg->parent) {
> -		quota =3D RUNTIME_INF;
> -	} else {
> +	if (tg->parent) {
>  		struct cfs_bandwidth *parent_b =3D &tg->parent->cfs_bandwidth;
> -
> +		s64 parent_quota =3D parent_b->hierarchical_quota;
>  		quota =3D normalize_cfs_quota(tg, d);
> -		parent_quota =3D parent_b->hierarchical_quota;
>=20=20
>  		/*
>  		 * Ensure max(child_quota) <=3D parent_quota.  On cgroup2,