3.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
commit 9916e214998a4a363b152b637245e5c958067350 upstream.
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@xxxxxxxxxxxxx>
Cc: ktkhai@xxxxxxxxxxxxx
Cc: rostedt@xxxxxxxxxxx
Cc: juri.lelli@xxxxxxxxx
Cc: pang.xunlei@xxxxxxxxxx
Cc: oleg@xxxxxxxxxx
Cc: wanpeng.li@xxxxxxxxxxxxxxx
Cc: umgwanakikbuti@xxxxxxxxx
Link: http://lkml.kernel.org/r/20150611124742.968262663@xxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Byungchul Park <byungchul.park@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/sched/deadline.c | 34 +++++++++++++++++++++-------------
1 file changed, 21 insertions(+), 13 deletions(-)
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -210,16 +210,23 @@ static inline int has_pushable_dl_tasks(
static int push_dl_task(struct rq *rq);
-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);
}
#else
@@ -247,6 +254,10 @@ void dec_dl_migration(struct sched_dl_en
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);
@@ -1541,7 +1552,7 @@ static void switched_from_dl(struct rq *
* from an overloaded cpu, if any.
*/
if (!rq->dl.dl_nr_running)
- pull_dl_task(rq);
+ queue_pull_task(rq);
#endif
}
@@ -1551,8 +1562,6 @@ static void switched_from_dl(struct rq *
*/
static void switched_to_dl(struct rq *rq, struct task_struct *p)
{
- int check_resched = 1;
-
/*
* If p is throttled, don't consider the possibility
* of preempting rq->curr, the check will be done right
@@ -1563,12 +1572,12 @@ static void switched_to_dl(struct rq *rq
if (p->on_rq || rq->curr != p) {
#ifdef CONFIG_SMP
- if (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 && task_has_dl_policy(rq->curr))
+ if (rq->dl.overloaded)
+ queue_push_tasks(rq);
+#else
+ if (task_has_dl_policy(rq->curr))
check_preempt_curr_dl(rq, p, 0);
+#endif /* CONFIG_SMP */
}
}
@@ -1588,15 +1597,14 @@ static void prio_changed_dl(struct rq *r
* 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_task(p);
#else
/*
--
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