Hi Kirill,
On 21/10/14 17:35, Kirill Tkhai wrote:
>
> 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.
>
> Completely untested, just RFC.
>
> Juri how about this?
>
I'll have to give it a spin, but it looks good.
Thanks,
- Juri
> Signed-off-by: Kirill Tkhai <ktk...@parallels.com>
> ---
> 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 256e577..937a875 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -532,7 +532,7 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer
> *timer)
> 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);
> @@ -1607,8 +1607,12 @@ 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 majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
