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[109.151.228.137]) by smtp.gmail.com with ESMTPSA id c3-20020adfe703000000b0031773a8e5c4sm9527466wrm.37.2023.08.20.08.23.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 20 Aug 2023 08:23:08 -0700 (PDT) From: Qais Yousef To: stable@vger.kernel.org Cc: Juri Lelli , Waiman Long , Tejun Heo , Dietmar Eggemann , Peter Zijlstra , Vincent Guittot , Ingo Molnar , Hao Luo , John Stultz , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Qais Yousef Subject: [PATCH 6/6] cgroup/cpuset: Free DL BW in case can_attach() fails Date: Sun, 20 Aug 2023 16:22:58 +0100 Message-Id: <20230820152258.518128-7-qyousef@layalina.io> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230820152258.518128-1-qyousef@layalina.io> References: <20230820152258.518128-1-qyousef@layalina.io> 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" From: Dietmar Eggemann commit 2ef269ef1ac006acf974793d975539244d77b28f upstream. cpuset_can_attach() can fail. Postpone DL BW allocation until all tasks have been checked. DL BW is not allocated per-task but as a sum over all DL tasks migrating. If multiple controllers are attached to the cgroup next to the cpuset controller a non-cpuset can_attach() can fail. In this case free DL BW in cpuset_cancel_attach(). Finally, update cpuset DL task count (nr_deadline_tasks) only in cpuset_attach(). Suggested-by: Waiman Long Signed-off-by: Dietmar Eggemann Signed-off-by: Juri Lelli Reviewed-by: Waiman Long Signed-off-by: Tejun Heo (cherry picked from commit 2ef269ef1ac006acf974793d975539244d77b28f) [Conflict in kernel/cgroup/cpuset.c due to pulling extra neighboring functions that are not applicable on this branch.] Signed-off-by: Qais Yousef (Google) --- include/linux/sched.h | 2 +- kernel/cgroup/cpuset.c | 51 ++++++++++++++++++++++++++++++++++++++---- kernel/sched/core.c | 17 ++------------ 3 files changed, 50 insertions(+), 20 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 91fe1d6418e7..7bfc2b45cd99 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1797,7 +1797,7 @@ 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 task_can_attach(struct task_struct *p); extern int dl_bw_alloc(int cpu, u64 dl_bw); extern void dl_bw_free(int cpu, u64 dl_bw); #ifdef CONFIG_SMP diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 63c8939503cb..6905079c15c2 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -167,6 +167,8 @@ struct cpuset { * know when to rebuild associated root domain bandwidth information. */ int nr_deadline_tasks; + int nr_migrate_dl_tasks; + u64 sum_migrate_dl_bw; =20 /* Handle for cpuset.cpus.partition */ struct cgroup_file partition_file; @@ -2206,16 +2208,23 @@ static int fmeter_getrate(struct fmeter *fmp) =20 static struct cpuset *cpuset_attach_old_cs; =20 +static void reset_migrate_dl_data(struct cpuset *cs) +{ + cs->nr_migrate_dl_tasks =3D 0; + cs->sum_migrate_dl_bw =3D 0; +} + /* Called by cgroups to determine if a cpuset is usable; cpuset_mutex held= */ static int cpuset_can_attach(struct cgroup_taskset *tset) { struct cgroup_subsys_state *css; - struct cpuset *cs; + struct cpuset *cs, *oldcs; struct task_struct *task; int ret; =20 /* used later by cpuset_attach() */ cpuset_attach_old_cs =3D task_cs(cgroup_taskset_first(tset, &css)); + oldcs =3D cpuset_attach_old_cs; cs =3D css_cs(css); =20 mutex_lock(&cpuset_mutex); @@ -2227,7 +2236,7 @@ static int cpuset_can_attach(struct cgroup_taskset *t= set) goto out_unlock; =20 cgroup_taskset_for_each(task, css, tset) { - ret =3D task_can_attach(task, cs->effective_cpus); + ret =3D task_can_attach(task); if (ret) goto out_unlock; ret =3D security_task_setscheduler(task); @@ -2235,11 +2244,31 @@ static int cpuset_can_attach(struct cgroup_taskset = *tset) goto out_unlock; =20 if (dl_task(task)) { - cs->nr_deadline_tasks++; - cpuset_attach_old_cs->nr_deadline_tasks--; + cs->nr_migrate_dl_tasks++; + cs->sum_migrate_dl_bw +=3D task->dl.dl_bw; } } =20 + if (!cs->nr_migrate_dl_tasks) + goto out_success; + + if (!cpumask_intersects(oldcs->effective_cpus, cs->effective_cpus)) { + int cpu =3D cpumask_any_and(cpu_active_mask, cs->effective_cpus); + + if (unlikely(cpu >=3D nr_cpu_ids)) { + reset_migrate_dl_data(cs); + ret =3D -EINVAL; + goto out_unlock; + } + + ret =3D dl_bw_alloc(cpu, cs->sum_migrate_dl_bw); + if (ret) { + reset_migrate_dl_data(cs); + goto out_unlock; + } + } + +out_success: /* * Mark attach is in progress. This makes validate_change() fail * changes which zero cpus/mems_allowed. @@ -2263,6 +2292,14 @@ static void cpuset_cancel_attach(struct cgroup_tasks= et *tset) cs->attach_in_progress--; if (!cs->attach_in_progress) wake_up(&cpuset_attach_wq); + + if (cs->nr_migrate_dl_tasks) { + int cpu =3D cpumask_any(cs->effective_cpus); + + dl_bw_free(cpu, cs->sum_migrate_dl_bw); + reset_migrate_dl_data(cs); + } + mutex_unlock(&cpuset_mutex); } =20 @@ -2335,6 +2372,12 @@ static void cpuset_attach(struct cgroup_taskset *tse= t) =20 cs->old_mems_allowed =3D cpuset_attach_nodemask_to; =20 + if (cs->nr_migrate_dl_tasks) { + cs->nr_deadline_tasks +=3D cs->nr_migrate_dl_tasks; + oldcs->nr_deadline_tasks -=3D cs->nr_migrate_dl_tasks; + reset_migrate_dl_data(cs); + } + cs->attach_in_progress--; if (!cs->attach_in_progress) wake_up(&cpuset_attach_wq); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index da2a2906a826..2324b7055260 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8789,8 +8789,7 @@ int cpuset_cpumask_can_shrink(const struct cpumask *c= ur, return ret; } =20 -int task_can_attach(struct task_struct *p, - const struct cpumask *cs_effective_cpus) +int task_can_attach(struct task_struct *p) { int ret =3D 0; =20 @@ -8803,21 +8802,9 @@ int task_can_attach(struct task_struct *p, * success of set_cpus_allowed_ptr() on all attached tasks * before cpus_mask may be changed. */ - if (p->flags & PF_NO_SETAFFINITY) { + if (p->flags & PF_NO_SETAFFINITY) ret =3D -EINVAL; - goto out; - } - - if (dl_task(p) && !cpumask_intersects(task_rq(p)->rd->span, - cs_effective_cpus)) { - int cpu =3D cpumask_any_and(cpu_active_mask, cs_effective_cpus); =20 - if (unlikely(cpu >=3D nr_cpu_ids)) - return -EINVAL; - ret =3D dl_bw_alloc(cpu, p->dl.dl_bw); - } - -out: return ret; } =20 --=20 2.34.1