[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <ZSPS+jMcJEd+ZR28@gmail.com>
Date: Mon, 9 Oct 2023 12:16:26 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Yajun Deng <yajun.deng@...ux.dev>
Cc: mingo@...hat.com, peterz@...radead.org, juri.lelli@...hat.com,
vincent.guittot@...aro.org, dietmar.eggemann@....com,
rostedt@...dmis.org, bsegall@...gle.com, mgorman@...e.de,
bristot@...hat.com, vschneid@...hat.com,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] sched/rt: Move sched_rt_entity::back to under the
CONFIG_RT_GROUP_SCHED block
* Yajun Deng <yajun.deng@...ux.dev> wrote:
> The member back in struct sched_rt_entity only related to RT_GROUP_SCHED,
> So move sched_rt_entity::back to under the CONFIG_RT_GROUP_SCHED block. It
> will save a few bytes.
>
> Also, init child when parent isn't NULL in init_tg_rt_entry().
>
> Signed-off-by: Yajun Deng <yajun.deng@...ux.dev>
> ---
> include/linux/sched.h | 2 +-
> kernel/sched/rt.c | 18 +++++++++---------
> 2 files changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 292c31697248..d0fe56603e60 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -597,8 +597,8 @@ struct sched_rt_entity {
> unsigned short on_rq;
> unsigned short on_list;
>
> - struct sched_rt_entity *back;
> #ifdef CONFIG_RT_GROUP_SCHED
> + struct sched_rt_entity *back;
> struct sched_rt_entity *parent;
> /* rq on which this entity is (to be) queued: */
> struct rt_rq *rt_rq;
Title claims this change - the rest of the changes should be in a separate
patch:
> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
> index 642edbd24ffb..7b3105b875f1 100644
> --- a/kernel/sched/rt.c
> +++ b/kernel/sched/rt.c
> @@ -233,8 +233,10 @@ void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
>
> if (!parent)
> rt_se->rt_rq = &rq->rt;
> - else
> + else {
> rt_se->rt_rq = parent->my_q;
> + parent->back = rt_se;
> + }
>
> rt_se->my_q = rt_rq;
> rt_se->parent = parent;
> @@ -1441,23 +1443,21 @@ static void __dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flag
> */
> static void dequeue_rt_stack(struct sched_rt_entity *rt_se, unsigned int flags)
> {
> - struct sched_rt_entity *back = NULL;
> + struct sched_rt_entity *root = NULL;
> unsigned int rt_nr_running;
>
> - for_each_sched_rt_entity(rt_se) {
> - rt_se->back = back;
> - back = rt_se;
> - }
> + for_each_sched_rt_entity(rt_se)
> + root = rt_se;
>
> - rt_nr_running = rt_rq_of_se(back)->rt_nr_running;
> + rt_nr_running = rt_rq_of_se(root)->rt_nr_running;
>
> - rt_se = back;
> + rt_se = root;
> for_each_sched_rt_entity_back(rt_se) {
> if (on_rt_rq(rt_se))
> __dequeue_rt_entity(rt_se, flags);
> }
>
> - dequeue_top_rt_rq(rt_rq_of_se(back), rt_nr_running);
> + dequeue_top_rt_rq(rt_rq_of_se(root), rt_nr_running);
> }
>
> static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
> --
> 2.25.1
Thanks,
Ingo
Powered by blists - more mailing lists