Commit-ID: f3a7e1a9c464a32ee186ab91388313c82e7ce018 Gitweb: http://git.kernel.org/tip/f3a7e1a9c464a32ee186ab91388313c82e7ce018 Author: Kirill Tkhai <[email protected]> AuthorDate: Tue, 21 Oct 2014 20:35:56 +0400 Committer: Ingo Molnar <[email protected]> CommitDate: Tue, 28 Oct 2014 10:46:10 +0100
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 <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: Juri Lelli <[email protected]> Cc: Linus Torvalds <[email protected]> Link: http://lkml.kernel.org/r/1413909356.19914.128.camel@tkhai Signed-off-by: Ingo Molnar <[email protected]> --- kernel/sched/deadline.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 4616789..5285332 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -540,7 +540,7 @@ again: dl_se->dl_yielded = 0; if (task_on_rq_queued(p)) { enqueue_task_dl(rq, p, ENQUEUE_REPLENISH); - if (task_has_dl_policy(rq->curr)) + if (dl_task(rq->curr)) check_preempt_curr_dl(rq, p, 0); else resched_curr(rq); @@ -1626,8 +1626,12 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p) /* Only reschedule if pushing failed */ check_resched = 0; #endif /* CONFIG_SMP */ - if (check_resched && task_has_dl_policy(rq->curr)) - check_preempt_curr_dl(rq, p, 0); + if (check_resched) { + if (dl_task(rq->curr)) + check_preempt_curr_dl(rq, p, 0); + else + resched_curr(rq); + } } } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
