From nobody Sun Feb 8 09:23:08 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 EFF10C6FD1F for ; Wed, 22 Mar 2023 09:23:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230496AbjCVJXk (ORCPT ); Wed, 22 Mar 2023 05:23:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37410 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230466AbjCVJX1 (ORCPT ); Wed, 22 Mar 2023 05:23:27 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A833A274; Wed, 22 Mar 2023 02:23:01 -0700 (PDT) Date: Wed, 22 Mar 2023 09:22:25 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1679476945; h=from:from:sender:sender:reply-to: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=ZELIwYZ8L6F5pqqKps8wkN2X6To3X1oeIsElFB0L0V8=; b=HjTMiV7QRJ/MT/Zq4ooAr06xd+LNTMe+msUy/j567bNmeLpcDgg9oU+4F+q1DRroHGoybh PmIDx7+kpXFgeQlNzCSJ++ljgHZBNYEpbaIcYdHE+dxzN4GYkxnx6hb8GFoIWS+riYHGoV V97OqjZnJIllwH0FMrtvPgZ6aii5u3zY63upoO9g69xSWM3UpUld2Ddde8pu6sce8aWVGL Lj9ALBoCQSs+g7jUif66FLQ4bpdf9W0wrxC5so1i7j+m5mM9OHxGJuIiNsm/gKl7ZXX4vC dsgZUCTYKlinASKk+vqGb7GY+c8jGNHSg6mpQ9q1fBd+kL6RG3AeKnSJO85B7Q== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1679476945; h=from:from:sender:sender:reply-to: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=ZELIwYZ8L6F5pqqKps8wkN2X6To3X1oeIsElFB0L0V8=; b=LGUyAjDTF2fufNfZxRdJiDVGxHoZmNqMYCUwJUy5KhFnc+fEVBCa2yhaX4CsHO1id/4DSz Wip49NCKwtwF5EBQ== From: "tip-bot2 for Hao Jia" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched/core: Avoid selecting the task that is throttled to run when core-sched enable Cc: Cruz Zhao , Hao Jia , "Peter Zijlstra (Intel)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20230316081806.69544-1-jiahao.os@bytedance.com> References: <20230316081806.69544-1-jiahao.os@bytedance.com> MIME-Version: 1.0 Message-ID: <167947694502.5837.16156353798978583164.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/core branch of tip: Commit-ID: 530bfad1d53d103f98cec66a3e491a36d397884d Gitweb: https://git.kernel.org/tip/530bfad1d53d103f98cec66a3e491a36d= 397884d Author: Hao Jia AuthorDate: Thu, 16 Mar 2023 16:18:06 +08:00 Committer: Peter Zijlstra CommitterDate: Wed, 22 Mar 2023 10:10:58 +01:00 sched/core: Avoid selecting the task that is throttled to run when core-sch= ed enable When {rt, cfs}_rq or dl task is throttled, since cookied tasks are not dequeued from the core tree, So sched_core_find() and sched_core_next() may return throttled task, which may cause throttled task to run on the CPU. So we add checks in sched_core_find() and sched_core_next() to make sure that the return is a runnable task that is not throttled. Co-developed-by: Cruz Zhao Signed-off-by: Cruz Zhao Signed-off-by: Hao Jia Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20230316081806.69544-1-jiahao.os@bytedance.= com --- kernel/sched/core.c | 60 +++++++++++++++++++++++++++------------- kernel/sched/deadline.c | 10 +++++++- kernel/sched/fair.c | 16 +++++++++++- kernel/sched/rt.c | 19 +++++++++++++- kernel/sched/sched.h | 4 +++- 5 files changed, 90 insertions(+), 19 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 488655f..9140a33 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -261,36 +261,51 @@ void sched_core_dequeue(struct rq *rq, struct task_st= ruct *p, int flags) resched_curr(rq); } =20 -/* - * Find left-most (aka, highest priority) task matching @cookie. - */ -static struct task_struct *sched_core_find(struct rq *rq, unsigned long co= okie) +static int sched_task_is_throttled(struct task_struct *p, int cpu) { - struct rb_node *node; - - node =3D rb_find_first((void *)cookie, &rq->core_tree, rb_sched_core_cmp); - /* - * The idle task always matches any cookie! - */ - if (!node) - return idle_sched_class.pick_task(rq); + if (p->sched_class->task_is_throttled) + return p->sched_class->task_is_throttled(p, cpu); =20 - return __node_2_sc(node); + return 0; } =20 static struct task_struct *sched_core_next(struct task_struct *p, unsigned= long cookie) { struct rb_node *node =3D &p->core_node; + int cpu =3D task_cpu(p); + + do { + node =3D rb_next(node); + if (!node) + return NULL; + + p =3D __node_2_sc(node); + if (p->core_cookie !=3D cookie) + return NULL; + + } while (sched_task_is_throttled(p, cpu)); + + return p; +} + +/* + * Find left-most (aka, highest priority) and unthrottled task matching @c= ookie. + * If no suitable task is found, NULL will be returned. + */ +static struct task_struct *sched_core_find(struct rq *rq, unsigned long co= okie) +{ + struct task_struct *p; + struct rb_node *node; =20 - node =3D rb_next(node); + node =3D rb_find_first((void *)cookie, &rq->core_tree, rb_sched_core_cmp); if (!node) return NULL; =20 - p =3D container_of(node, struct task_struct, core_node); - if (p->core_cookie !=3D cookie) - return NULL; + p =3D __node_2_sc(node); + if (!sched_task_is_throttled(p, rq->cpu)) + return p; =20 - return p; + return sched_core_next(p, cookie); } =20 /* @@ -6236,7 +6251,7 @@ static bool try_steal_cookie(int this, int that) goto unlock; =20 p =3D sched_core_find(src, cookie); - if (p =3D=3D src->idle) + if (!p) goto unlock; =20 do { @@ -6248,6 +6263,13 @@ static bool try_steal_cookie(int this, int that) =20 if (p->core_occupation > dst->idle->core_occupation) goto next; + /* + * sched_core_find() and sched_core_next() will ensure that task @p + * is not throttled now, we also need to check whether the runqueue + * of the destination CPU is being throttled. + */ + if (sched_task_is_throttled(p, this)) + goto next; =20 deactivate_task(src, p, 0); set_task_cpu(p, this); diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 71b2437..4cc7e1c 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2704,6 +2704,13 @@ static void prio_changed_dl(struct rq *rq, struct ta= sk_struct *p, #endif } =20 +#ifdef CONFIG_SCHED_CORE +static int task_is_throttled_dl(struct task_struct *p, int cpu) +{ + return p->dl.dl_throttled; +} +#endif + DEFINE_SCHED_CLASS(dl) =3D { =20 .enqueue_task =3D enqueue_task_dl, @@ -2736,6 +2743,9 @@ DEFINE_SCHED_CLASS(dl) =3D { .switched_to =3D switched_to_dl, =20 .update_curr =3D update_curr_dl, +#ifdef CONFIG_SCHED_CORE + .task_is_throttled =3D task_is_throttled_dl, +#endif }; =20 /* Used for dl_bw check and update, used under sched_rt_handler()::mutex */ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 7a1b1f8..b572367 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -11933,6 +11933,18 @@ bool cfs_prio_less(const struct task_struct *a, co= nst struct task_struct *b, =20 return delta > 0; } + +static int task_is_throttled_fair(struct task_struct *p, int cpu) +{ + struct cfs_rq *cfs_rq; + +#ifdef CONFIG_FAIR_GROUP_SCHED + cfs_rq =3D task_group(p)->cfs_rq[cpu]; +#else + cfs_rq =3D &cpu_rq(cpu)->cfs; +#endif + return throttled_hierarchy(cfs_rq); +} #else static inline void task_tick_core(struct rq *rq, struct task_struct *curr)= {} #endif @@ -12559,6 +12571,10 @@ DEFINE_SCHED_CLASS(fair) =3D { .task_change_group =3D task_change_group_fair, #endif =20 +#ifdef CONFIG_SCHED_CORE + .task_is_throttled =3D task_is_throttled_fair, +#endif + #ifdef CONFIG_UCLAMP_TASK .uclamp_enabled =3D 1, #endif diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 0a11f44..9d67dfb 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -2677,6 +2677,21 @@ static unsigned int get_rr_interval_rt(struct rq *rq= , struct task_struct *task) return 0; } =20 +#ifdef CONFIG_SCHED_CORE +static int task_is_throttled_rt(struct task_struct *p, int cpu) +{ + struct rt_rq *rt_rq; + +#ifdef CONFIG_RT_GROUP_SCHED + rt_rq =3D task_group(p)->rt_rq[cpu]; +#else + rt_rq =3D &cpu_rq(cpu)->rt; +#endif + + return rt_rq_throttled(rt_rq); +} +#endif + DEFINE_SCHED_CLASS(rt) =3D { =20 .enqueue_task =3D enqueue_task_rt, @@ -2710,6 +2725,10 @@ DEFINE_SCHED_CLASS(rt) =3D { =20 .update_curr =3D update_curr_rt, =20 +#ifdef CONFIG_SCHED_CORE + .task_is_throttled =3D task_is_throttled_rt, +#endif + #ifdef CONFIG_UCLAMP_TASK .uclamp_enabled =3D 1, #endif diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 3e8df6d..0606169 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2224,6 +2224,10 @@ struct sched_class { #ifdef CONFIG_FAIR_GROUP_SCHED void (*task_change_group)(struct task_struct *p); #endif + +#ifdef CONFIG_SCHED_CORE + int (*task_is_throttled)(struct task_struct *p, int cpu); +#endif }; =20 static inline void put_prev_task(struct rq *rq, struct task_struct *prev)