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Commit 9916e214 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Thomas Gleixner
Browse files

sched, dl: Convert switched_{from, to}_dl() / prio_changed_dl() to balance callbacks 



Remove the direct {push,pull} balancing operations from
switched_{from,to}_dl() / prio_changed_dl() 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: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124742.968262663@infradead.org


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 0ea60c20

kernel/sched/deadline.c

+24 −21
Original line number Diff line number Diff line
@@ -213,16 +213,23 @@ static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev) 
	return dl_task(prev);

}



static DEFINE_PER_CPU(struct callback_head, dl_balance_head);

static DEFINE_PER_CPU(struct callback_head, dl_push_head);

static DEFINE_PER_CPU(struct callback_head, dl_pull_head);



static void push_dl_tasks(struct rq *);

static void pull_dl_task(struct rq *);



static inline void queue_push_tasks(struct rq *rq)

{

	if (!has_pushable_dl_tasks(rq))

		return;



	queue_balance_callback(rq, &per_cpu(dl_balance_head, rq->cpu), push_dl_tasks);

	queue_balance_callback(rq, &per_cpu(dl_push_head, rq->cpu), push_dl_tasks);

}



static inline void queue_pull_task(struct rq *rq)

{

	queue_balance_callback(rq, &per_cpu(dl_pull_head, rq->cpu), pull_dl_task);

}



static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq);
@@ -305,6 +312,10 @@ static inline void pull_dl_task(struct rq *rq) 
static inline void queue_push_tasks(struct rq *rq)

{

}



static inline void queue_pull_task(struct rq *rq)

{

}

#endif /* CONFIG_SMP */



static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags);
@@ -1040,8 +1051,6 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p) 
	resched_curr(rq);

}



static void pull_dl_task(struct rq *this_rq);



#endif /* CONFIG_SMP */



/*
@@ -1705,7 +1714,7 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p) 
	if (!task_on_rq_queued(p) || rq->dl.dl_nr_running)

		return;



	pull_dl_task(rq);

	queue_pull_task(rq);

}



/*
@@ -1714,21 +1723,16 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p) 
 */

static void switched_to_dl(struct rq *rq, struct task_struct *p)

{

	int check_resched = 1;



	if (task_on_rq_queued(p) && rq->curr != p) {

#ifdef CONFIG_SMP

		if (p->nr_cpus_allowed > 1 && rq->dl.overloaded &&

			push_dl_task(rq) && rq != task_rq(p))

			/* Only reschedule if pushing failed */

			check_resched = 0;

#endif /* CONFIG_SMP */

		if (check_resched) {

		if (p->nr_cpus_allowed > 1 && rq->dl.overloaded)

			queue_push_tasks(rq);

#else

		if (dl_task(rq->curr))

			check_preempt_curr_dl(rq, p, 0);

		else

			resched_curr(rq);

		}

#endif

	}

}
@@ -1748,15 +1752,14 @@ static void prio_changed_dl(struct rq *rq, struct task_struct *p, 
		 * or lowering its prio, so...

		 */

		if (!rq->dl.overloaded)

			pull_dl_task(rq);

			queue_pull_task(rq);



		/*

		 * If we now have a earlier deadline task than p,

		 * then reschedule, provided p is still on this

		 * runqueue.

		 */

		if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline) &&

		    rq->curr == p)

		if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline))

			resched_curr(rq);

#else

		/*