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Thu, 30 Apr 2026 14:39:17 -0700 (PDT) Received: from yuri-framework13 ([78.211.51.156]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-44a9879ef89sm418510f8f.30.2026.04.30.14.39.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Apr 2026 14:39:17 -0700 (PDT) From: Yuri Andriaccio To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider Cc: linux-kernel@vger.kernel.org, Luca Abeni , Yuri Andriaccio Subject: [RFC PATCH v5 23/29] sched/rt: Hook HCBS migration functions Date: Thu, 30 Apr 2026 23:38:27 +0200 Message-ID: <20260430213835.62217-24-yurand2000@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260430213835.62217-1-yurand2000@gmail.com> References: <20260430213835.62217-1-yurand2000@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: luca abeni Hook rt-cgroup migration functions: - balance_rt - set_next_task_rt - task_woken_rt - switched_from_rt - switched_to_rt - prio_changed_rt Follow the same patterns as for the standard FIFO/RR scheduling, but for HCBS cgroups. - put_prev_task_rt If a server is throttled, put_prev_task_rt is invoked and a push is necessary so that the task can keep running on another server if possible. Update select_task_rq_rt to always return the cpu where the task is scheduled. Update switched_to_rt to keep track of the deadline server that is assigned to the task switching to FIFO/RR priority. Co-developed-by: Alessio Balsini Signed-off-by: Alessio Balsini Co-developed-by: Andrea Parri Signed-off-by: Andrea Parri Co-developed-by: Yuri Andriaccio Signed-off-by: Yuri Andriaccio Signed-off-by: luca abeni --- kernel/sched/rt.c | 59 ++++++++++++++++++++++++++++++++++++----------- 1 file changed, 45 insertions(+), 14 deletions(-) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index e1731e01757b..e6b3efa358d3 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1,4 +1,3 @@ -#pragma GCC diagnostic ignored "-Wunused-function" // SPDX-License-Identifier: GPL-2.0 /* * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR @@ -906,6 +905,11 @@ select_task_rq_rt(struct task_struct *p, int cpu, int flags) struct rq *rq; bool test; + /* Just return the task_cpu for processes inside task groups */ + if (IS_ENABLED(CONFIG_RT_GROUP_SCHED) && + is_dl_group(rt_rq_of_se(&p->rt))) + goto out; + /* For anything but wake ups, just return the task_cpu */ if (!(flags & (WF_TTWU | WF_FORK))) goto out; @@ -1005,7 +1009,10 @@ static int balance_rt(struct rq *rq, struct task_struct *p, struct rq_flags *rf) * not yet started the picking loop. */ rq_unpin_lock(rq, rf); - pull_rt_task(rq); + if (IS_ENABLED(CONFIG_RT_GROUP_SCHED) && is_dl_group(rt_rq_of_se(&p->rt))) + group_pull_rt_task(rt_rq_of_se(&p->rt)); + else + pull_rt_task(rq); rq_repin_lock(rq, rf); } @@ -1120,7 +1127,9 @@ static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, bool f if (rq->donor->sched_class != &rt_sched_class) update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 0); - if (!IS_ENABLED(CONFIG_RT_GROUP_SCHED) || !is_dl_group(rt_rq)) + if (IS_ENABLED(CONFIG_RT_GROUP_SCHED) && is_dl_group(rt_rq)) + rt_queue_push_from_group(rt_rq); + else rt_queue_push_tasks(rt_rq); } @@ -1174,6 +1183,13 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p, struct task_s */ if (on_rt_rq(&p->rt) && p->nr_cpus_allowed > 1) enqueue_pushable_task(rt_rq, p); + + if (IS_ENABLED(CONFIG_RT_GROUP_SCHED) && is_dl_group(rt_rq)) { + struct sched_dl_entity *dl_se = dl_group_of(rt_rq); + + if (dl_se->dl_throttled) + rt_queue_push_from_group(rt_rq); + } } /* Only try algorithms three times */ @@ -2214,6 +2230,7 @@ static void group_push_rt_tasks(struct rt_rq *rt_rq) { } */ static void task_woken_rt(struct rq *rq, struct task_struct *p) { + struct rt_rq *rt_rq = rt_rq_of_se(&p->rt); bool need_to_push = !task_on_cpu(rq, p) && !test_tsk_need_resched(rq->curr) && p->nr_cpus_allowed > 1 && @@ -2221,7 +2238,12 @@ static void task_woken_rt(struct rq *rq, struct task_struct *p) (rq->curr->nr_cpus_allowed < 2 || rq->donor->prio <= p->prio); - if (need_to_push) + if (!need_to_push) + return; + + if (IS_ENABLED(CONFIG_RT_GROUP_SCHED) && is_dl_group(rt_rq)) + group_push_rt_tasks(rt_rq); + else push_rt_tasks(rq); } @@ -2261,7 +2283,9 @@ static void switched_from_rt(struct rq *rq, struct task_struct *p) if (!task_on_rq_queued(p) || rt_rq->rt_nr_running) return; - if (!IS_ENABLED(CONFIG_RT_GROUP_SCHED) || !is_dl_group(rt_rq)) + if (IS_ENABLED(CONFIG_RT_GROUP_SCHED) && is_dl_group(rt_rq)) + rt_queue_pull_to_group(rt_rq); + else rt_queue_pull_task(rt_rq); } @@ -2290,6 +2314,13 @@ static void switched_to_rt(struct rq *rq, struct task_struct *p) */ if (task_current(rq, p)) { update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 0); + + if (IS_ENABLED(CONFIG_RT_GROUP_SCHED) && is_dl_group(rt_rq_of_se(&p->rt))) { + struct sched_dl_entity *dl_se = dl_group_of(rt_rq_of_se(&p->rt)); + + p->dl_server = dl_se; + } + return; } @@ -2299,13 +2330,10 @@ static void switched_to_rt(struct rq *rq, struct task_struct *p) * then see if we can move to another run queue. */ if (task_on_rq_queued(p)) { - if (IS_ENABLED(CONFIG_RT_GROUP_SCHED) && is_dl_group(rt_rq)) { - if (p->prio < rq->donor->prio) - resched_curr(rq); - } else { - if (p->nr_cpus_allowed > 1 && rq->rt.overloaded) - rt_queue_push_tasks(rt_rq_of_se(&p->rt)); - } + if (!is_dl_group(rt_rq) && p->nr_cpus_allowed > 1 && rq->rt.overloaded) + rt_queue_push_tasks(rt_rq); + else if (is_dl_group(rt_rq) && rt_rq->overloaded) + rt_queue_push_from_group(rt_rq); if (p->prio < rq->donor->prio && cpu_online(cpu_of(rq))) resched_curr(rq); @@ -2332,9 +2360,12 @@ prio_changed_rt(struct rq *rq, struct task_struct *p, u64 oldprio) * If our priority decreases while running, we * may need to pull tasks to this runqueue. */ - if (oldprio < p->prio) - if (!IS_ENABLED(CONFIG_RT_GROUP_SCHED) || !is_dl_group(rt_rq)) + if (oldprio < p->prio) { + if (IS_ENABLED(CONFIG_RT_GROUP_SCHED) && is_dl_group(rt_rq)) + rt_queue_pull_to_group(rt_rq); + else rt_queue_pull_task(rt_rq); + } /* * If there's a higher priority task waiting to run -- 2.53.0