From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50B09CE7B0C for ; Thu, 28 Sep 2023 08:52:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231378AbjI1Iwl (ORCPT ); Thu, 28 Sep 2023 04:52:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44120 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230111AbjI1Iwf (ORCPT ); Thu, 28 Sep 2023 04:52:35 -0400 Received: from out-209.mta0.migadu.com (out-209.mta0.migadu.com [91.218.175.209]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1DC64C0 for ; Thu, 28 Sep 2023 01:52:33 -0700 (PDT) Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1695891151; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=h6YvlznqxvWuAukC+g68ihPuz53Yf7CKktPIwkut/8k=; b=eiFvDFfA5JNFYrfLCWGCoZ121EI+Wri1IWuiRsB9y4jyqQJuILccd8PYLglspXWY09GoQD Ne1gBqgFJGFkmcAk1Qw1RHq/2J1njJVpZuHaWcA2j667rvnKKHDjioDvfhpvT96E+73CgD Qbo9CffmU1FDI5V2P1zNEklI3++D9e0= Date: Thu, 28 Sep 2023 16:52:22 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v2] sched/rt: move back to RT_GROUP_SCHED and rename it child Content-Language: en-US To: 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 Cc: linux-kernel@vger.kernel.org References: <20230920140127.1671945-1-yajun.deng@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Yajun Deng In-Reply-To: <20230920140127.1671945-1-yajun.deng@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Steve, Kindly ping... Thank. On 2023/9/20 22:01, Yajun Deng wrote: > The member back in struct sched_rt_entity only related to RT_GROUP_SCHED, > it should not place out of RT_GROUP_SCHED, move back to RT_GROUP_SCHED > and rename it child. This would save a few bytes. > > Init child when parent isn't NULL in init_tg_rt_entry() and introduce > for_each_sched_rt_entity_reverse() to iterate rt_se from top to down. > > Signed-off-by: Yajun Deng > --- > v2: fix the "uninitialized symbol 'root'" warning > v1: https://lore.kernel.org/all/20230919035114.2364567-1-yajun.deng@linux.dev/ > --- > include/linux/sched.h | 2 +- > kernel/sched/rt.c | 25 ++++++++++++++++--------- > 2 files changed, 17 insertions(+), 10 deletions(-) > > diff --git a/include/linux/sched.h b/include/linux/sched.h > index 7fcf1b82cfa6..cd05f4bb6a26 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -594,8 +594,8 @@ 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 *child; > struct sched_rt_entity *parent; > /* rq on which this entity is (to be) queued: */ > struct rt_rq *rt_rq; > diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c > index 0597ba0f85ff..473a21b76c62 100644 > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -230,8 +230,10 @@ 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->child = rt_se; > + } > > rt_se->my_q = rt_rq; > rt_se->parent = parent; > @@ -564,6 +566,9 @@ static inline struct task_group *next_task_group(struct task_group *tg) > #define for_each_sched_rt_entity(rt_se) \ > for (; rt_se; rt_se = rt_se->parent) > > +#define for_each_sched_rt_entity_reverse(rt_se) \ > + for (; rt_se; rt_se = rt_se->child) > + > static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se) > { > return rt_se->my_q; > @@ -669,6 +674,9 @@ typedef struct rt_rq *rt_rq_iter_t; > #define for_each_sched_rt_entity(rt_se) \ > for (; rt_se; rt_se = NULL) > > +#define for_each_sched_rt_entity_reverse(rt_se) \ > + for_each_sched_rt_entity(rt_se) > + > static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se) > { > return NULL; > @@ -1481,22 +1489,21 @@ 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; > > - for (rt_se = back; rt_se; rt_se = rt_se->back) { > + rt_se = root; > + for_each_sched_rt_entity_reverse(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)