From nobody Sun Apr 12 05:50:40 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 E8B9CC00144 for ; Mon, 1 Aug 2022 04:28:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239151AbiHAE25 (ORCPT ); Mon, 1 Aug 2022 00:28:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53994 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239502AbiHAE2f (ORCPT ); Mon, 1 Aug 2022 00:28:35 -0400 Received: from mail-pl1-x632.google.com (mail-pl1-x632.google.com [IPv6:2607:f8b0:4864:20::632]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 011F013F1B for ; Sun, 31 Jul 2022 21:28:29 -0700 (PDT) Received: by mail-pl1-x632.google.com with SMTP id x10so8697431plb.3 for ; Sun, 31 Jul 2022 21:28:28 -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=qM5t1EVQbnssjElUyFkZNByPxLswIQhwSrHRz48dXWo=; b=xi9UjcUW4iBi+IuxTN6mmZ+i3gBKqsgjnolzaRD3dRQzotiZXRfETFn9aT3Hu4npwy cSI1WasmgaKz0rgy2K0jcHtdHfrFigSYylueA9L6dBqTQEwCv2MRTXqSpZUJGR7ETbOS okqJtj0iYbIv240aKWtH+maYhgiWtcpojYn+1iZjCHMbEUPlwhE9gZT/qeLVccHcf0xw PCuSdigQeaH/l3WTMB3E5IHXOJfBxkwE0bVt1zjuA/9Yb8ALqmq8rkwMJy5ItgXSzAe7 lf5S5q7q6ZS6Di3Aby5HLsKaVxMjmnmjFhSsN9PwQP8tgneqN30yjmaIGCsles6qT4jW lzrw== 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=qM5t1EVQbnssjElUyFkZNByPxLswIQhwSrHRz48dXWo=; b=HR6YXjqE/vLCL75GPdvwuw2ZNRqmUnVLL4onX9eKhH6i8zThUFM4FINJnCXDL6QO4Q 76S/Hdr4nSe0AW21BvfHnoOELnLq1H35miHmrBUiZ0Zlp1JYWmL/XQFbtYDgBmd94D16 gW9R7We9RKwfc8n1ys348B/RMrEZQbegxKoTSXPCr/rFpNGBWeAwR65xSaju0UiyPvnJ eARg7GFZoFT5qOg75A0E7f4Q+bzIznD/jZqHZJh1J7CgdSPZRWwD9QECfrC+wAlFFC1P TNFIHK2Q0l3QPfGuZFDHtGnJu4Zde6Ty/AQ6fkWj/aIjw+DIcviGWqNhQP2silSuFojE pVrQ== X-Gm-Message-State: ACgBeo37RVqDwaRCAJuV8bM4QedpnIujW4K253QLJ5FT4GmwSji7RI0+ JiNw2SemJOBUol6eX0i0cZcCyQ== X-Google-Smtp-Source: AA6agR4KB/qhLFEe6ItaP7mbifr1Td54rTx+xkyl6aZ+rbJmPb/C9iyZlCt0Uxq+kHSuOh6IFs9oHg== X-Received: by 2002:a17:902:a502:b0:16b:fbd9:7fc5 with SMTP id s2-20020a170902a50200b0016bfbd97fc5mr15350849plq.112.1659328108379; Sun, 31 Jul 2022 21:28:28 -0700 (PDT) Received: from C02CV1DAMD6P.bytedance.net ([139.177.225.241]) by smtp.gmail.com with ESMTPSA id ot10-20020a17090b3b4a00b001f326ead012sm7012202pjb.37.2022.07.31.21.28.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 31 Jul 2022 21:28:28 -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 v3 07/10] sched/fair: allow changing cgroup of new forked task Date: Mon, 1 Aug 2022 12:27:42 +0800 Message-Id: <20220801042745.7794-8-zhouchengming@bytedance.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220801042745.7794-1-zhouchengming@bytedance.com> References: <20220801042745.7794-1-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" commit 7dc603c9028e ("sched/fair: Fix PELT integrity for new tasks") introduce a TASK_NEW state and an unnessary limitation that would fail when changing cgroup of new forked task. Because at that time, we can't handle task_change_group_fair() for new forked fair task which hasn't been woken up by wake_up_new_task(), which will cause detach on an unattached task sched_avg problem. This patch delete this unnessary limitation by adding check before do attach_entity_cfs_rq(). Signed-off-by: Chengming Zhou --- include/linux/sched.h | 5 ++--- kernel/sched/core.c | 30 +++++++----------------------- kernel/sched/fair.c | 7 ++++++- 3 files changed, 15 insertions(+), 27 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 88b8817b827d..b504e55bbf7a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -95,10 +95,9 @@ struct task_group; #define TASK_WAKEKILL 0x0100 #define TASK_WAKING 0x0200 #define TASK_NOLOAD 0x0400 -#define TASK_NEW 0x0800 /* RT specific auxilliary flag to mark RT lock waiters */ -#define TASK_RTLOCK_WAIT 0x1000 -#define TASK_STATE_MAX 0x2000 +#define TASK_RTLOCK_WAIT 0x0800 +#define TASK_STATE_MAX 0x1000 =20 /* Convenience macros for the sake of set_current_state: */ #define TASK_KILLABLE (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 614d7180c99e..220bce5e73e0 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4500,11 +4500,11 @@ int sched_fork(unsigned long clone_flags, struct ta= sk_struct *p) { __sched_fork(clone_flags, p); /* - * We mark the process as NEW here. This guarantees that + * We mark the process as running here. This guarantees that * nobody will actually run it, and a signal or other external * event cannot wake it up and insert it on the runqueue either. */ - p->__state =3D TASK_NEW; + p->__state =3D TASK_RUNNING; =20 /* * Make sure we do not leak PI boosting priority to the child. @@ -4622,7 +4622,6 @@ void wake_up_new_task(struct task_struct *p) struct rq *rq; =20 raw_spin_lock_irqsave(&p->pi_lock, rf.flags); - WRITE_ONCE(p->__state, TASK_RUNNING); #ifdef CONFIG_SMP /* * Fork balancing, do it here and not earlier because: @@ -10249,36 +10248,19 @@ static void cpu_cgroup_css_free(struct cgroup_sub= sys_state *css) sched_unregister_group(tg); } =20 +#ifdef CONFIG_RT_GROUP_SCHED static int cpu_cgroup_can_attach(struct cgroup_taskset *tset) { struct task_struct *task; struct cgroup_subsys_state *css; - int ret =3D 0; =20 cgroup_taskset_for_each(task, css, tset) { -#ifdef CONFIG_RT_GROUP_SCHED if (!sched_rt_can_attach(css_tg(css), task)) return -EINVAL; -#endif - /* - * Serialize against wake_up_new_task() such that if it's - * running, we're sure to observe its full state. - */ - raw_spin_lock_irq(&task->pi_lock); - /* - * Avoid calling sched_move_task() before wake_up_new_task() - * has happened. This would lead to problems with PELT, due to - * move wanting to detach+attach while we're not attached yet. - */ - if (READ_ONCE(task->__state) =3D=3D TASK_NEW) - ret =3D -EINVAL; - raw_spin_unlock_irq(&task->pi_lock); - - if (ret) - break; } - return ret; + return 0; } +#endif =20 static void cpu_cgroup_attach(struct cgroup_taskset *tset) { @@ -11114,7 +11096,9 @@ 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, +#ifdef CONFIG_RT_GROUP_SCHED .can_attach =3D cpu_cgroup_can_attach, +#endif .attach =3D cpu_cgroup_attach, .legacy_cftypes =3D cpu_legacy_files, .dfl_cftypes =3D cpu_files, diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index a32da4e71ddf..ad20a939227d 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -11603,7 +11603,12 @@ static void attach_task_cfs_rq(struct task_struct = *p) struct sched_entity *se =3D &p->se; struct cfs_rq *cfs_rq =3D cfs_rq_of(se); =20 - attach_entity_cfs_rq(se); + /* + * We couldn't detach or attach a forked task which + * hasn't been woken up by wake_up_new_task(). + */ + if (p->on_rq || se->sum_exec_runtime) + attach_entity_cfs_rq(se); =20 if (!vruntime_normalized(p)) se->vruntime +=3D cfs_rq->min_vruntime; --=20 2.36.1