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[31.46.242.55]) by smtp.gmail.com with ESMTPSA id d9-20020adff2c9000000b00324887a13f7sm9239728wrp.0.2023.10.09.03.16.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Oct 2023 03:16:28 -0700 (PDT) Sender: Ingo Molnar Date: Mon, 9 Oct 2023 12:16:26 +0200 From: Ingo Molnar To: Yajun Deng Cc: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] sched/rt: Move sched_rt_entity::back to under the CONFIG_RT_GROUP_SCHED block Message-ID: References: <20231005162317.3343678-1-yajun.deng@linux.dev> <20231005162317.3343678-3-yajun.deng@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231005162317.3343678-3-yajun.deng@linux.dev> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Yajun Deng 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 > --- > 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