From nobody Sat Apr 11 00:44:32 2026 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 942A4C25B08 for ; Thu, 18 Aug 2022 03:45:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242985AbiHRDpy (ORCPT ); Wed, 17 Aug 2022 23:45:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39610 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240595AbiHRDpu (ORCPT ); Wed, 17 Aug 2022 23:45:50 -0400 Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9A969411C for ; Wed, 17 Aug 2022 20:45:48 -0700 (PDT) Received: by mail-pj1-x1032.google.com with SMTP id pm17so515090pjb.3 for ; Wed, 17 Aug 2022 20:45:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc; bh=cq9WBgnay6MlRUXX21E7/GvZMXn3RD4DJtZwNfGfMLY=; b=fTH5AQyb70fbfjzlPmrKwqpWI2SN6Od0VKvQz6oIZ7Fg+Y3Ts8vMIYQ4VzD+NctwzY wFtEdbFJXZdB21cu+PUhjUGJHE00nc06JqyfJO2QY8LH1iuTmTZNls53hj+s8uOWSe6J zShxU+lDP1bDlf5Yvmq02EBGYehI0YNkQIuVebBAeiJu0QGP5bz0JrDa3fNNDpCHHQ1T W4HKzDeZdjN5wGPk85t6j6ikaKoFCV6CAXmWaJhTaVGZeKZnz7yMYPEyQ6/hBPB3v7VC 1HP9eIqDDKH+soDgezn+mhlwNttM00itCfF6LfVeJzuIf8ag0FhYvFeom1cA3XOL7Thj skvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc; bh=cq9WBgnay6MlRUXX21E7/GvZMXn3RD4DJtZwNfGfMLY=; b=N8Aw+AblhwzI/C0kby7mbEamVG+f2mdBAsXqFJrzdaGcdNyQfyTc89+LZZovQT9vEf 8GB3TjUyl5zab147rl66/g6RnHE5sbo04V3042PYs+ej9p7jTe+SSPKmBCHjGE0yVfTg 42uSMhAIQsOFWRWOJIiyXylihENVPnBMna3mxa9mfipyAVBW3mJB2sLUozm0M5Agtp6f jYOfOidZF9OTxSEa3I2E3fPM8ObCoYMAHF9xEnjFb0ypF6EqZopYDsEnyiGdeAg5PNa1 6emqj8xGgR9dLEJEyCFYrNRXZjksNA6kolcSqTf65MvF8NTs29mjubtwPJH02HJCGwez Vqpg== X-Gm-Message-State: ACgBeo38KANKPquAzYfTkY66Vg/S7vSFkTLKdxrMJv4a4XDsvtbkSSU6 hCD/t4RF4vJpJBSXqqUGgm3qKA== X-Google-Smtp-Source: AA6agR78ZlGtoG4klkFQJzLwLDgdqVBEL6qnJTx9iF7Txr5I02iW14OUuhDG4Ztfzmc0rZ/hI98XLA== X-Received: by 2002:a17:90b:1b45:b0:1f5:753d:82bc with SMTP id nv5-20020a17090b1b4500b001f5753d82bcmr6778457pjb.68.1660794348305; Wed, 17 Aug 2022 20:45:48 -0700 (PDT) Received: from C02CV1DAMD6P.bytedance.net ([139.177.225.246]) by smtp.gmail.com with ESMTPSA id m11-20020a65564b000000b00419acadde52sm268700pgs.46.2022.08.17.20.45.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Aug 2022 20:45:48 -0700 (PDT) From: Chengming Zhou To: vincent.guittot@linaro.org, dietmar.eggemann@arm.com, mingo@redhat.com, peterz@infradead.org, rostedt@goodmis.org, bsegall@google.com, vschneid@redhat.com Cc: linux-kernel@vger.kernel.org, tj@kernel.org, Chengming Zhou Subject: [PATCH v5 2/9] sched/fair: remove redundant cpu_cgrp_subsys->fork() Date: Thu, 18 Aug 2022 11:43:36 +0800 Message-Id: <20220818034343.87625-3-zhouchengming@bytedance.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220818034343.87625-1-zhouchengming@bytedance.com> References: <20220818034343.87625-1-zhouchengming@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" We use cpu_cgrp_subsys->fork() to set task group for the new fair task in cgroup_post_fork(). Since commit b1e8206582f9 ("sched: Fix yet more sched_fork() races") has already set_task_rq() for the new fair task in sched_cgroup_fork(), so cpu_cgrp_subsys->fork() can be removed. cgroup_can_fork() --> pin parent's sched_task_group sched_cgroup_fork() __set_task_cpu() set_task_rq() cgroup_post_fork() ss->fork() :=3D cpu_cgroup_fork() sched_change_group(..., TASK_SET_GROUP) task_set_group_fair() set_task_rq() --> can be removed After this patch's change, task_change_group_fair() only need to care about task cgroup migration, make the code much simplier. Signed-off-by: Chengming Zhou Reviewed-by: Vincent Guittot Reviewed-by: Dietmar Eggemann --- kernel/sched/core.c | 27 ++++----------------------- kernel/sched/fair.c | 23 +---------------------- kernel/sched/sched.h | 5 +---- 3 files changed, 6 insertions(+), 49 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 863b5203e357..8e3f1c3f0b2c 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -481,8 +481,7 @@ sched_core_dequeue(struct rq *rq, struct task_struct *p= , int flags) { } * p->se.load, p->rt_priority, * p->dl.dl_{runtime, deadline, period, flags, bw, density} * - sched_setnuma(): p->numa_preferred_nid - * - sched_move_task()/ - * cpu_cgroup_fork(): p->sched_task_group + * - sched_move_task(): p->sched_task_group * - uclamp_update_active() p->uclamp* * * p->state <- TASK_*: @@ -10166,7 +10165,7 @@ void sched_release_group(struct task_group *tg) spin_unlock_irqrestore(&task_group_lock, flags); } =20 -static void sched_change_group(struct task_struct *tsk, int type) +static void sched_change_group(struct task_struct *tsk) { struct task_group *tg; =20 @@ -10182,7 +10181,7 @@ static void sched_change_group(struct task_struct *= tsk, int type) =20 #ifdef CONFIG_FAIR_GROUP_SCHED if (tsk->sched_class->task_change_group) - tsk->sched_class->task_change_group(tsk, type); + tsk->sched_class->task_change_group(tsk); else #endif set_task_rq(tsk, task_cpu(tsk)); @@ -10213,7 +10212,7 @@ void sched_move_task(struct task_struct *tsk) if (running) put_prev_task(rq, tsk); =20 - sched_change_group(tsk, TASK_MOVE_GROUP); + sched_change_group(tsk); =20 if (queued) enqueue_task(rq, tsk, queue_flags); @@ -10291,23 +10290,6 @@ static void cpu_cgroup_css_free(struct cgroup_subs= ys_state *css) sched_unregister_group(tg); } =20 -/* - * This is called before wake_up_new_task(), therefore we really only - * have to set its group bits, all the other stuff does not apply. - */ -static void cpu_cgroup_fork(struct task_struct *task) -{ - struct rq_flags rf; - struct rq *rq; - - rq =3D task_rq_lock(task, &rf); - - update_rq_clock(rq); - sched_change_group(task, TASK_SET_GROUP); - - task_rq_unlock(rq, task, &rf); -} - static int cpu_cgroup_can_attach(struct cgroup_taskset *tset) { struct task_struct *task; @@ -11173,7 +11155,6 @@ struct cgroup_subsys cpu_cgrp_subsys =3D { .css_released =3D cpu_cgroup_css_released, .css_free =3D cpu_cgroup_css_free, .css_extra_stat_show =3D cpu_extra_stat_show, - .fork =3D cpu_cgroup_fork, .can_attach =3D cpu_cgroup_can_attach, .attach =3D cpu_cgroup_attach, .legacy_cftypes =3D cpu_legacy_files, diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c5ee08b187ec..4b95599aa951 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -11821,15 +11821,7 @@ void init_cfs_rq(struct cfs_rq *cfs_rq) } =20 #ifdef CONFIG_FAIR_GROUP_SCHED -static void task_set_group_fair(struct task_struct *p) -{ - struct sched_entity *se =3D &p->se; - - set_task_rq(p, task_cpu(p)); - se->depth =3D se->parent ? se->parent->depth + 1 : 0; -} - -static void task_move_group_fair(struct task_struct *p) +static void task_change_group_fair(struct task_struct *p) { detach_task_cfs_rq(p); set_task_rq(p, task_cpu(p)); @@ -11841,19 +11833,6 @@ static void task_move_group_fair(struct task_struc= t *p) attach_task_cfs_rq(p); } =20 -static void task_change_group_fair(struct task_struct *p, int type) -{ - switch (type) { - case TASK_SET_GROUP: - task_set_group_fair(p); - break; - - case TASK_MOVE_GROUP: - task_move_group_fair(p); - break; - } -} - void free_fair_sched_group(struct task_group *tg) { int i; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 628ffa974123..2db7b0494c19 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2195,11 +2195,8 @@ struct sched_class { =20 void (*update_curr)(struct rq *rq); =20 -#define TASK_SET_GROUP 0 -#define TASK_MOVE_GROUP 1 - #ifdef CONFIG_FAIR_GROUP_SCHED - void (*task_change_group)(struct task_struct *p, int type); + void (*task_change_group)(struct task_struct *p); #endif }; =20 --=20 2.37.2