3.16.36-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Peter Zijlstra <pet...@infradead.org>
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) <pet...@infradead.org>
Cc: ktk...@parallels.com
Cc: rost...@goodmis.org
Cc: juri.le...@gmail.com
Cc: pang.xun...@linaro.org
Cc: o...@redhat.com
Cc: wanpeng...@linux.intel.com
Cc: umgwanakikb...@gmail.com
Link: http://lkml.kernel.org/r/20150611124742.968262...@infradead.org
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
[Conflicts: kernel/sched/deadline.c]
Signed-off-by: Byungchul Park <byungchul.p...@lge.com>
[bwh: Backported to 3.16:
- The check_resched / !CONFIG_SMP case in switched_to_dl() is different
- Adjust context]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
kernel/sched/deadline.c | 42 +++++++++++++++++++++++-------------------
1 file changed, 23 insertions(+), 19 deletions(-)
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -213,16 +213,23 @@ static inline bool need_pull_dl_task(str
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);
}
#else
@@ -259,6 +266,10 @@ static inline void pull_dl_task(struct r
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);
@@ -956,8 +967,6 @@ static void check_preempt_equal_dl(struc
resched_task(rq->curr);
}
-static void pull_dl_task(struct rq *this_rq);
-
#endif /* CONFIG_SMP */
/*
@@ -1562,7 +1571,7 @@ 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
}
@@ -1572,8 +1581,6 @@ 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
@@ -1584,12 +1591,12 @@ 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 */
}
}
@@ -1609,15 +1616,14 @@ 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
/*
