diff options
author | Kirill Tkhai <ktkhai@parallels.com> | 2014-10-21 12:35:56 -0400 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2014-10-28 05:46:10 -0400 |
commit | f3a7e1a9c464a32ee186ab91388313c82e7ce018 (patch) | |
tree | 74d90ab7172a01aa653b88570322eb900789a562 /kernel/sched | |
parent | fcd964dda5ece2fa77f78f843bc3455348787282 (diff) |
sched/dl: Fix preemption checks
1) switched_to_dl() check is wrong. We reschedule only
if rq->curr is deadline task, and we do not reschedule
if it's a lower priority task. But we must always
preempt a task of other classes.
2) dl_task_timer():
Policy does not change in case of priority inheritance.
rt_mutex_setprio() changes prio, while policy remains old.
So we lose some balancing logic in dl_task_timer() and
switched_to_dl() when we check policy instead of priority. Boosted
task may be rq->curr.
(I didn't change switched_from_dl() because no check is necessary
there at all).
I've looked at this place(switched_to_dl) several times and even fixed
this function, but found just now... I suppose some performance tests
may work better after this.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1413909356.19914.128.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r-- | kernel/sched/deadline.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 46167899d852..5285332392d5 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c | |||
@@ -540,7 +540,7 @@ again: | |||
540 | dl_se->dl_yielded = 0; | 540 | dl_se->dl_yielded = 0; |
541 | if (task_on_rq_queued(p)) { | 541 | if (task_on_rq_queued(p)) { |
542 | enqueue_task_dl(rq, p, ENQUEUE_REPLENISH); | 542 | enqueue_task_dl(rq, p, ENQUEUE_REPLENISH); |
543 | if (task_has_dl_policy(rq->curr)) | 543 | if (dl_task(rq->curr)) |
544 | check_preempt_curr_dl(rq, p, 0); | 544 | check_preempt_curr_dl(rq, p, 0); |
545 | else | 545 | else |
546 | resched_curr(rq); | 546 | resched_curr(rq); |
@@ -1626,8 +1626,12 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p) | |||
1626 | /* Only reschedule if pushing failed */ | 1626 | /* Only reschedule if pushing failed */ |
1627 | check_resched = 0; | 1627 | check_resched = 0; |
1628 | #endif /* CONFIG_SMP */ | 1628 | #endif /* CONFIG_SMP */ |
1629 | if (check_resched && task_has_dl_policy(rq->curr)) | 1629 | if (check_resched) { |
1630 | check_preempt_curr_dl(rq, p, 0); | 1630 | if (dl_task(rq->curr)) |
1631 | check_preempt_curr_dl(rq, p, 0); | ||
1632 | else | ||
1633 | resched_curr(rq); | ||
1634 | } | ||
1631 | } | 1635 | } |
1632 | } | 1636 | } |
1633 | 1637 | ||