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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: Peter 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: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Peter Zijlstra 2015-06-11 14:46:43 +02:00 committed by Thomas Gleixner
parent 0ea60c2054
commit 9916e21499
1 changed files with 24 additions and 21 deletions
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45
kernel/sched/deadline.c
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@ -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 (dl_task(rq->curr))
check_preempt_curr_dl(rq, p, 0);
else
resched_curr(rq);
}
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
/*