From: Peter Zijlstra <peterz@infradead.org>
To: umgwanakikbuti@gmail.com, mingo@elte.hu
Cc: ktkhai@parallels.com, rostedt@goodmis.org, juri.lelli@gmail.com,
pang.xunlei@linaro.org, oleg@redhat.com,
linux-kernel@vger.kernel.org,
"Peter Zijlstra" <peterz@infradead.org>
Subject: [RFC][PATCH 5/7] sched,rt: Convert switched_{from,to}_rt() / prio_changed_rt() to balance callbacks
Date: Mon, 01 Jun 2015 15:58:23 +0200 [thread overview]
Message-ID: <20150601140840.059114492@infradead.org> (raw)
In-Reply-To: 20150601135818.506080835@infradead.org
[-- Attachment #1: peterz-sched-post_schedule-3.patch --]
[-- Type: text/plain, Size: 3009 bytes --]
Remove the direct {push,pull} balancing operations from
switched_{from,to}_rt() / prio_changed_rt() and use the balance
callback queue.
Again, err on the side of too many reschedules; since too few is a
hard bug while too many is just annoying.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/sched/rt.c | 35 +++++++++++++++++++----------------
1 file changed, 19 insertions(+), 16 deletions(-)
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -354,16 +354,23 @@ static inline int has_pushable_tasks(str
return !plist_head_empty(&rq->rt.pushable_tasks);
}
-static DEFINE_PER_CPU(struct callback_head, rt_balance_head);
+static DEFINE_PER_CPU(struct callback_head, rt_push_head);
+static DEFINE_PER_CPU(struct callback_head, rt_pull_head);
static void push_rt_tasks(struct rq *);
+static void pull_rt_task(struct rq *);
static inline void queue_push_tasks(struct rq *rq)
{
if (!has_pushable_tasks(rq))
return;
- queue_balance_callback(rq, &per_cpu(rt_balance_head, rq->cpu), push_rt_tasks);
+ queue_balance_callback(rq, &per_cpu(rt_push_head, rq->cpu), push_rt_tasks);
+}
+
+static inline void queue_pull_task(struct rq *rq)
+{
+ queue_balance_callback(rq, &per_cpu(rt_pull_head, rq->cpu), pull_rt_task);
}
static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
@@ -2139,7 +2146,7 @@ static void switched_from_rt(struct rq *
if (!task_on_rq_queued(p) || rq->rt.rt_nr_running)
return;
- pull_rt_task(rq);
+ queue_pull_task(rq);
}
void __init init_sched_rt_class(void)
@@ -2160,8 +2167,6 @@ void __init init_sched_rt_class(void)
*/
static void switched_to_rt(struct rq *rq, struct task_struct *p)
{
- int check_resched = 1;
-
/*
* If we are already running, then there's nothing
* that needs to be done. But if we are not running
@@ -2171,13 +2176,12 @@ static void switched_to_rt(struct rq *rq
*/
if (task_on_rq_queued(p) && rq->curr != p) {
#ifdef CONFIG_SMP
- if (p->nr_cpus_allowed > 1 && rq->rt.overloaded &&
- /* Don't resched if we changed runqueues */
- push_rt_task(rq) && rq != task_rq(p))
- check_resched = 0;
-#endif /* CONFIG_SMP */
- if (check_resched && p->prio < rq->curr->prio)
+ if (p->nr_cpus_allowed > 1 && rq->rt.overloaded)
+ queue_push_tasks(rq);
+#else
+ if (p->prio < rq->curr->prio)
resched_curr(rq);
+#endif /* CONFIG_SMP */
}
}
@@ -2198,14 +2202,13 @@ prio_changed_rt(struct rq *rq, struct ta
* may need to pull tasks to this runqueue.
*/
if (oldprio < p->prio)
- pull_rt_task(rq);
+ queue_pull_task(rq);
+
/*
* If there's a higher priority task waiting to run
- * then reschedule. Note, the above pull_rt_task
- * can release the rq lock and p could migrate.
- * Only reschedule if p is still on the same runqueue.
+ * then reschedule.
*/
- if (p->prio > rq->rt.highest_prio.curr && rq->curr == p)
+ if (p->prio > rq->rt.highest_prio.curr)
resched_curr(rq);
#else
/* For UP simply resched on drop of prio */
next prev parent reply other threads:[~2015-06-01 14:15 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-01 13:58 [RFC][PATCH 0/7] sched: balance callbacks Peter Zijlstra
2015-06-01 13:58 ` [RFC][PATCH 1/7] sched: Replace post_schedule with a balance callback list Peter Zijlstra
2015-06-03 4:41 ` Kamalesh Babulal
2015-06-03 7:21 ` Peter Zijlstra
2015-06-03 8:24 ` pang.xunlei
2015-06-03 8:55 ` Peter Zijlstra
2015-06-05 7:13 ` pang.xunlei
2015-06-05 7:19 ` Peter Zijlstra
2015-06-01 13:58 ` [RFC][PATCH 2/7] sched: Use replace normalize_task() with __sched_setscheduler() Peter Zijlstra
2015-06-01 13:58 ` [RFC][PATCH 3/7] sched: Allow balance callbacks for check_class_changed() Peter Zijlstra
2015-06-02 13:58 ` Kirill Tkhai
2015-06-02 14:27 ` Peter Zijlstra
2015-06-02 16:07 ` Peter Zijlstra
2015-06-02 16:27 ` Kirill Tkhai
2015-06-03 7:32 ` Peter Zijlstra
2015-06-03 10:40 ` Kirill Tkhai
2015-06-03 10:42 ` Kirill Tkhai
2015-06-03 10:45 ` Peter Zijlstra
2015-06-01 13:58 ` [RFC][PATCH 4/7] sched,rt: Remove return value from pull_rt_task() Peter Zijlstra
2015-06-01 13:58 ` Peter Zijlstra [this message]
2015-06-01 13:58 ` [RFC][PATCH 6/7] sched,dl: Remove return value from pull_dl_task() Peter Zijlstra
2015-06-01 13:58 ` [RFC][PATCH 7/7] sched,dl: Convert switched_{from,to}_dl() / prio_changed_dl() to balance callbacks Peter Zijlstra
2015-06-03 4:52 ` Kamalesh Babulal
2015-06-01 14:16 ` [RFC][PATCH 0/7] sched: " Peter Zijlstra
2015-06-01 14:42 ` Mike Galbraith
2015-06-02 6:48 ` Mike Galbraith
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