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From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org, juri.lelli@redhat.com
Cc: linux-kernel@vger.kernel.org, dietmar.eggemann@arm.com,
	luca.abeni@santannapisa.it, bristot@redhat.com,
	balsini@android.com, dvyukov@google.com, tglx@linutronix.de,
	vpillai@digitalocean.com, rostedt@goodmis.org,
	peterz@infradead.org
Subject: [RFC][PATCH 13/13] sched/fair: Add trivial fair server
Date: Fri, 26 Jul 2019 16:54:22 +0200
Message-ID: <20190726161358.113257053@infradead.org> (raw)
In-Reply-To: <20190726145409.947503076@infradead.org>



Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/sched/core.c     |    6 +++++-
 kernel/sched/deadline.c |    2 ++
 kernel/sched/fair.c     |   29 +++++++++++++++++++++++++++++
 kernel/sched/sched.h    |    6 +++++-
 4 files changed, 41 insertions(+), 2 deletions(-)

--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6501,6 +6504,7 @@ void __init sched_init(void)
 #endif /* CONFIG_SMP */
 		hrtick_rq_init(rq);
 		atomic_set(&rq->nr_iowait, 0);
+		fair_server_init(rq);
 	}
 
 	set_load_weight(&init_task, false);
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5239,6 +5239,9 @@ enqueue_task_fair(struct rq *rq, struct
 	 */
 	util_est_enqueue(&rq->cfs, p);
 
+	if (!rq->cfs.h_nr_running)
+		dl_server_start(&rq->fair_server);
+
 	/*
 	 * If in_iowait is set, the code below may not trigger any cpufreq
 	 * utilization updates, so do it here explicitly with the IOWAIT flag
@@ -5374,6 +5377,9 @@ static void dequeue_task_fair(struct rq
 	if (!se)
 		sub_nr_running(rq, 1);
 
+	if (!rq->cfs.h_nr_running)
+		dl_server_stop(&rq->fair_server);
+
 	util_est_dequeue(&rq->cfs, p, task_sleep);
 	hrtick_update(rq);
 }
@@ -6903,6 +6909,29 @@ done: __maybe_unused;
 	return NULL;
 }
 
+static bool fair_server_has_tasks(struct sched_dl_entity *dl_se)
+{
+	return !!dl_se->rq->cfs.nr_running;
+}
+
+static struct task_struct *fair_server_pick(struct sched_dl_entity *dl_se)
+{
+	return pick_next_task_fair(dl_se->rq, NULL, NULL);
+}
+
+void fair_server_init(struct rq *rq)
+{
+	struct sched_dl_entity *dl_se = &rq->fair_server;
+
+	init_dl_entity(dl_se);
+
+	dl_se->dl_runtime = TICK_NSEC;
+	dl_se->dl_deadline = 20 * TICK_NSEC;
+	dl_se->dl_period = 20 * TICK_NSEC;
+
+	dl_server_init(dl_se, rq, fair_server_has_tasks, fair_server_pick);
+}
+
 /*
  * Account for a descheduled task:
  */
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -345,6 +345,8 @@ extern void dl_server_init(struct sched_
 		    dl_server_has_tasks_f has_tasks,
 		    dl_server_pick_f pick);
 
+extern void fair_server_init(struct rq *);
+
 #ifdef CONFIG_CGROUP_SCHED
 
 #include <linux/cgroup.h>
@@ -905,6 +907,8 @@ struct rq {
 	struct rt_rq		rt;
 	struct dl_rq		dl;
 
+	struct sched_dl_entity	fair_server;
+
 #ifdef CONFIG_FAIR_GROUP_SCHED
 	/* list of leaf cfs_rq on this CPU: */
 	struct list_head	leaf_cfs_rq_list;
@@ -968,7 +972,7 @@ struct rq {
 
 	/* This is used to determine avg_idle's max value */
 	u64			max_idle_balance_cost;
-#endif
+#endif /* CONFIG_SMP */
 
 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
 	u64			prev_irq_time;



  parent reply index

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-26 14:54 [RFC][PATCH 00/13] SCHED_DEADLINE server infrastructure Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 01/13] sched/deadline: Impose global limits on sched_attr::sched_period Peter Zijlstra
2019-07-29  8:57   ` Juri Lelli
2019-07-29 11:45     ` Daniel Bristot de Oliveira
2019-08-02 17:21   ` Alessio Balsini
2019-08-05 11:53     ` Peter Zijlstra
2019-08-22 12:29       ` Alessio Balsini
2019-08-22 16:51         ` Peter Zijlstra
2019-08-31 14:41           ` Alessio Balsini
2019-09-02  9:16             ` Peter Zijlstra
2019-09-02 12:31               ` Peter Zijlstra
2019-09-04 10:16               ` Steven Rostedt
2019-09-04 11:30                 ` Peter Zijlstra
2019-09-04 13:24                   ` Joel Fernandes
2019-09-04 14:11                     ` Will Deacon
2019-09-04 14:35                       ` Joel Fernandes
2019-09-04 15:52                     ` Peter Zijlstra
2019-10-23 17:17       ` [PATCH 4.4 4.9 4.14] loop: Add LOOP_SET_DIRECT_IO to compat ioctl Alessio Balsini
2019-10-23 17:22         ` Alessio Balsini
2019-10-25  0:17         ` Sasha Levin
2020-05-20 18:38   ` [RFC][PATCH 01/13] sched/deadline: Impose global limits on sched_attr::sched_period Juri Lelli
2020-05-21 13:45     ` Daniel Bristot de Oliveira
2020-06-16 12:21   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 02/13] stop_machine: Fix stop_cpus_in_progress ordering Peter Zijlstra
2019-07-30 13:16   ` Phil Auld
2019-07-30 13:22   ` Steven Rostedt
2019-07-26 14:54 ` [RFC][PATCH 03/13] sched: Fix kerneldoc comment for ia64_set_curr_task Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 04/13] sched/{rt,deadline}: Fix set_next_task vs pick_next_task Peter Zijlstra
2019-07-29  9:25   ` Juri Lelli
2019-07-29 11:15     ` Peter Zijlstra
2019-07-29 11:27       ` Juri Lelli
2019-07-29 13:04         ` Peter Zijlstra
2019-07-29 13:17           ` Juri Lelli
2019-07-29 14:40             ` Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 05/13] sched: Add task_struct pointer to sched_class::set_curr_task Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 06/13] sched/fair: Export newidle_balance() Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 07/13] sched: Allow put_prev_task() to drop rq->lock Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 08/13] sched: Rework pick_next_task() slow-path Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 09/13] sched: Unify runtime accounting across classes Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 10/13] sched/deadline: Collect sched_dl_entity initialization Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 11/13] sched/deadline: Move bandwidth accounting into {en,de}queue_dl_entity Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 12/13] sched/deadline: Introduce deadline servers Peter Zijlstra
2019-08-07 16:31   ` Dietmar Eggemann
2019-08-08  6:52     ` Juri Lelli
2019-08-08  7:52       ` Dietmar Eggemann
2019-08-08  7:56     ` Peter Zijlstra
2019-08-08  8:11       ` Dietmar Eggemann
2019-08-08  8:46         ` Juri Lelli
2019-08-08  8:57           ` Dietmar Eggemann
2019-08-08  9:27             ` Juri Lelli
2019-08-08  9:45               ` Juri Lelli
2019-08-30 11:24                 ` Peter Zijlstra
2019-09-06  9:36                   ` Juri Lelli
2019-08-08 10:31           ` Peter Zijlstra
2019-08-09  7:13             ` Juri Lelli
2019-08-08  6:59   ` Juri Lelli
2019-08-09  9:17   ` Dietmar Eggemann
2019-08-09 12:16     ` Juri Lelli
2019-07-26 14:54 ` Peter Zijlstra [this message]
2019-07-26 20:01 ` [RFC][PATCH 00/13] SCHED_DEADLINE server infrastructure luca abeni
2019-09-03 14:27 ` Alessio Balsini
2019-09-04 10:50   ` Juri Lelli
2019-09-04 11:32     ` Peter Zijlstra

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