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 32763CCA47C for ; Sat, 9 Jul 2022 15:15:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229515AbiGIPPY (ORCPT ); Sat, 9 Jul 2022 11:15:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50936 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229509AbiGIPPV (ORCPT ); Sat, 9 Jul 2022 11:15:21 -0400 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 42AAD326C9 for ; Sat, 9 Jul 2022 08:15:20 -0700 (PDT) Received: by mail-pj1-x1035.google.com with SMTP id x18-20020a17090a8a9200b001ef83b332f5so4494813pjn.0 for ; Sat, 09 Jul 2022 08:15:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=IZT91HMRNNtPd10faSgbS3j67ADoK0u+DYdIQS+mTiY=; b=pR8HidnzAjT3a8n+geJywPAeXSIBe/KfkoyaAJoQcWrNvVWGI9oI/0tRm7V6x7sRhE h68GX0ZLVSNYqeG0QVdRDCSuLbUhbzPRlCpXzbQr/v32IUEMHzRPsxW3EDBxqjeQsbm8 fq1ikyte92bthqlhFKlNQtTCQmBPWWVxuoMCYN/kzuuUSaWjR72DlIy6y4TPuTIBgWgw 18CwI6NY+3r9CopD/GWWeb7qBvrj/Gw+vy0VGTLr1qXNjblEkbKfpcjAPmlI+pB4z+1j Xz+RfcqJHGqa+bIg/jKGG2d66dacY35DvmN0KvKDL7jklg01Od1VrYQFX/CpAJS1BOjW PCnw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=IZT91HMRNNtPd10faSgbS3j67ADoK0u+DYdIQS+mTiY=; b=vFPCrq95dQuNTGsd+gDI+4oceVjBPnM2I1JuaFJDpgjTcHcbbD4h3OhGp4Yg3kZzdG xl1ZiodfXxaI/iin+K8d9AICChuWkMAs83pZyn9d1RaMEd3Atln8bTzE3RKyd5plVO7D ivRQpDH3LpatnB2YyRVladca1dWVU8FJx10H1dWd0Ma3rv8vZQG2WJTVohy4qlAHlVOx hfxohUVIBAbIIvrZbBv6WCgjA+ppJR5WO5g/D6/irklcdzuo6+2V2f6hyBjKp3PhFGEm /Jb9d6J5+UFa29tPWc5DnwO9kkB8a5hKjZrgsfv5i3/fJ6wPqrA3KTfbS0P2fkrvV6Q0 fyew== X-Gm-Message-State: AJIora/7CoTZsMJxhUR5FtEeV3/w0VSVcRzWxog4n5m/A6j5l3gMqgrd 85BIIkOCDyVTQOxrN11gDlLRdQ== X-Google-Smtp-Source: AGRyM1swfGvYFgVFmPaq+46N7eBvo4NdhDZosSD4HyLFgqcT1blLZz/ZLuqU9i0kZmRkEFrjgcDJOw== X-Received: by 2002:a17:90a:d195:b0:1ef:b15e:8cb5 with SMTP id fu21-20020a17090ad19500b001efb15e8cb5mr6514559pjb.228.1657379719774; Sat, 09 Jul 2022 08:15:19 -0700 (PDT) Received: from localhost.localdomain ([2409:8a28:e63:e730:5493:aabd:e56d:65e6]) by smtp.gmail.com with ESMTPSA id bo20-20020a17090b091400b001ef8d2f72fesm1295709pjb.45.2022.07.09.08.15.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 09 Jul 2022 08:15:19 -0700 (PDT) From: Chengming Zhou To: mingo@redhat.com, peterz@infradead.org, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, vschneid@redhat.com Cc: linux-kernel@vger.kernel.org, Chengming Zhou Subject: [PATCH 1/8] sched/fair: combine detach into dequeue when migrating task Date: Sat, 9 Jul 2022 23:13:46 +0800 Message-Id: <20220709151353.32883-2-zhouchengming@bytedance.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220709151353.32883-1-zhouchengming@bytedance.com> References: <20220709151353.32883-1-zhouchengming@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When we are migrating task out of the CPU, we can combine detach and propagation into dequeue_entity() to save the detach_entity_cfs_rq() in migrate_task_rq_fair(). This optimization is like combining DO_ATTACH in the enqueue_entity() when migrating task to the CPU. So we don't have to traverse the CFS tree extra time to do the detach_entity_cfs_rq() -> propagate_entity_cfs_rq() call, which wouldn't be called anymore with this patch's change. detach_task() deactivate_task() dequeue_task_fair() for_each_sched_entity(se) dequeue_entity() update_load_avg() /* (1) */ detach_entity_load_avg() set_task_cpu() migrate_task_rq_fair() detach_entity_cfs_rq() /* (2) */ update_load_avg(); detach_entity_load_avg(); propagate_entity_cfs_rq(); for_each_sched_entity() update_load_avg() This patch save the detach_entity_cfs_rq() called in (2) by doing the detach_entity_load_avg() for a CPU migrating task inside (1) (the task being the first se in the loop) Signed-off-by: Chengming Zhou Reviewed-by: Vincent Guittot --- kernel/sched/fair.c | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index a78d2e3b9d49..0689b94ed70b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4003,6 +4003,7 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s #define UPDATE_TG 0x1 #define SKIP_AGE_LOAD 0x2 #define DO_ATTACH 0x4 +#define DO_DETACH 0x8 /* Update task and its cfs_rq load average */ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) @@ -4020,7 +4021,14 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s decayed = update_cfs_rq_load_avg(now, cfs_rq); decayed |= propagate_entity_load_avg(se); - if (!se->avg.last_update_time && (flags & DO_ATTACH)) { + if (flags & DO_DETACH) { + /* + * DO_DETACH means we're here from dequeue_entity() + * and we are migrating task out of the CPU. + */ + detach_entity_load_avg(cfs_rq, se); + update_tg_load_avg(cfs_rq); + } else if (!se->avg.last_update_time && (flags & DO_ATTACH)) { /* * DO_ATTACH means we're here from enqueue_entity(). @@ -4292,6 +4300,7 @@ static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq) #define UPDATE_TG 0x0 #define SKIP_AGE_LOAD 0x0 #define DO_ATTACH 0x0 +#define DO_DETACH 0x0 static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int not_used1) { @@ -4511,6 +4520,11 @@ static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq); static void dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) { + int action = UPDATE_TG; + + if (entity_is_task(se) && task_on_rq_migrating(task_of(se))) + action |= DO_DETACH; + /* * Update run-time statistics of the 'current'. */ @@ -4524,7 +4538,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) * - For group entity, update its weight to reflect the new share * of its group cfs_rq. */ - update_load_avg(cfs_rq, se, UPDATE_TG); + update_load_avg(cfs_rq, se, action); se_update_runnable(se); update_stats_dequeue_fair(cfs_rq, se, flags); @@ -7076,8 +7090,6 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags) return new_cpu; } -static void detach_entity_cfs_rq(struct sched_entity *se); - /* * Called immediately before a task is migrated to a new CPU; task_cpu(p) and * cfs_rq_of(p) references at time of call are still valid and identify the @@ -7099,15 +7111,7 @@ static void migrate_task_rq_fair(struct task_struct *p, int new_cpu) se->vruntime -= u64_u32_load(cfs_rq->min_vruntime); } - if (p->on_rq == TASK_ON_RQ_MIGRATING) { - /* - * In case of TASK_ON_RQ_MIGRATING we in fact hold the 'old' - * rq->lock and can modify state directly. - */ - lockdep_assert_rq_held(task_rq(p)); - detach_entity_cfs_rq(se); - - } else { + if (!task_on_rq_migrating(p)) { remove_entity_load_avg(se); /* -- 2.36.1