From nobody Mon Apr 13 08:23:01 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 28A7DC6FD1F for ; Wed, 22 Mar 2023 14:00:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231139AbjCVOAR (ORCPT ); Wed, 22 Mar 2023 10:00:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230272AbjCVOAN (ORCPT ); Wed, 22 Mar 2023 10:00:13 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id E82934691; Wed, 22 Mar 2023 07:00:11 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id AC51FAD7; Wed, 22 Mar 2023 07:00:55 -0700 (PDT) Received: from e125579.fritz.box (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 24D323F71E; Wed, 22 Mar 2023 07:00:09 -0700 (PDT) From: Dietmar Eggemann To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Waiman Long , Tejun Heo , Zefan Li , Johannes Weiner , Hao Luo Cc: Steven Rostedt , Vincent Guittot , Daniel Bristot de Oliveira , Luca Abeni , Tommaso Cucinotta , Qais Yousef , Wei Wang , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org Subject: [RFC PATCH 1/2] sched/deadline: Create DL BW alloc, free & check overflow interface Date: Wed, 22 Mar 2023 14:59:58 +0100 Message-Id: <20230322135959.1998790-2-dietmar.eggemann@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230322135959.1998790-1-dietmar.eggemann@arm.com> References: <20230322135959.1998790-1-dietmar.eggemann@arm.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" Rework the existing dl_cpu_busy() interface which offered DL BW overflow checking and per-task DL BW allocation. Add dl_bw_free() as an interface to be able to free DL BW. It will be used to allow freeing of the DL BW request done during cpuset_can_attach() in case multiple controllers are attached to the cgroup next to cpuset and one of the non-cpuset can_attach() fails. Signed-off-by: Dietmar Eggemann --- include/linux/sched.h | 2 ++ kernel/sched/core.c | 4 ++-- kernel/sched/deadline.c | 53 +++++++++++++++++++++++++++++++---------- kernel/sched/sched.h | 2 +- 4 files changed, 45 insertions(+), 16 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 4df2b3e76b30..658e997ba057 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1847,6 +1847,8 @@ current_restore_flags(unsigned long orig_flags, unsig= ned long flags) =20 extern int cpuset_cpumask_can_shrink(const struct cpumask *cur, const stru= ct cpumask *trial); extern int task_can_attach(struct task_struct *p, const struct cpumask *cs= _effective_cpus); +extern int dl_bw_alloc(int cpu, u64 dl_bw); +extern void dl_bw_free(int cpu, u64 dl_bw); #ifdef CONFIG_SMP extern void do_set_cpus_allowed(struct task_struct *p, const struct cpumas= k *new_mask); extern int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumas= k *new_mask); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index d586a8440348..2f07aecb7434 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -9226,7 +9226,7 @@ int task_can_attach(struct task_struct *p, =20 if (unlikely(cpu >=3D nr_cpu_ids)) return -EINVAL; - ret =3D dl_cpu_busy(cpu, p); + ret =3D dl_bw_alloc(cpu, p->dl.dl_bw); } =20 out: @@ -9511,7 +9511,7 @@ static void cpuset_cpu_active(void) static int cpuset_cpu_inactive(unsigned int cpu) { if (!cpuhp_tasks_frozen) { - int ret =3D dl_cpu_busy(cpu, NULL); + int ret =3D dl_bw_check_overflow(cpu); =20 if (ret) return ret; diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 71b24371a6f7..41ed6c6d2628 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -3033,26 +3033,38 @@ int dl_cpuset_cpumask_can_shrink(const struct cpuma= sk *cur, return ret; } =20 -int dl_cpu_busy(int cpu, struct task_struct *p) +enum dl_bw_request { + dl_bw_req_check_overflow =3D 0, + dl_bw_req_alloc, + dl_bw_req_free +}; + +static int dl_bw_manage(enum dl_bw_request req, int cpu, u64 dl_bw) { - unsigned long flags, cap; + unsigned long flags; struct dl_bw *dl_b; - bool overflow; + bool overflow =3D 0; =20 rcu_read_lock_sched(); dl_b =3D dl_bw_of(cpu); raw_spin_lock_irqsave(&dl_b->lock, flags); - cap =3D dl_bw_capacity(cpu); - overflow =3D __dl_overflow(dl_b, cap, 0, p ? p->dl.dl_bw : 0); =20 - if (!overflow && p) { - /* - * We reserve space for this task in the destination - * root_domain, as we can't fail after this point. - * We will free resources in the source root_domain - * later on (see set_cpus_allowed_dl()). - */ - __dl_add(dl_b, p->dl.dl_bw, dl_bw_cpus(cpu)); + if (req =3D=3D dl_bw_req_free) { + __dl_sub(dl_b, dl_bw, dl_bw_cpus(cpu)); + } else { + unsigned long cap =3D dl_bw_capacity(cpu); + + overflow =3D __dl_overflow(dl_b, cap, 0, dl_bw); + + if (req =3D=3D dl_bw_req_alloc && !overflow) { + /* + * We reserve space in the destination + * root_domain, as we can't fail after this point. + * We will free resources in the source root_domain + * later on (see set_cpus_allowed_dl()). + */ + __dl_add(dl_b, dl_bw, dl_bw_cpus(cpu)); + } } =20 raw_spin_unlock_irqrestore(&dl_b->lock, flags); @@ -3060,6 +3072,21 @@ int dl_cpu_busy(int cpu, struct task_struct *p) =20 return overflow ? -EBUSY : 0; } + +int dl_bw_check_overflow(int cpu) +{ + return dl_bw_manage(dl_bw_req_check_overflow, cpu, 0); +} + +int dl_bw_alloc(int cpu, u64 dl_bw) +{ + return dl_bw_manage(dl_bw_req_alloc, cpu, dl_bw); +} + +void dl_bw_free(int cpu, u64 dl_bw) +{ + dl_bw_manage(dl_bw_req_free, cpu, dl_bw); +} #endif =20 #ifdef CONFIG_SCHED_DEBUG diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 3e8df6d31c1e..6cb4cf878fe2 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -330,7 +330,7 @@ extern void __getparam_dl(struct task_struct *p, struct= sched_attr *attr); extern bool __checkparam_dl(const struct sched_attr *attr); extern bool dl_param_changed(struct task_struct *p, const struct sched_att= r *attr); extern int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur, const = struct cpumask *trial); -extern int dl_cpu_busy(int cpu, struct task_struct *p); +extern int dl_bw_check_overflow(int cpu); =20 #ifdef CONFIG_CGROUP_SCHED =20 --=20 2.25.1