Hi,
not sure I understand what the problem is here.
On 11/11/14 01:52, Wanpeng Li wrote:
> Queued ticks are scheduled to match the budget, which means the budget
> is overall consumed and the dl task should be throttled.
... enforce the budget? It means that when the budget is consumed the
task has to be throttled...
> Dl task will
> be replenished immediately if fail to start a dl timer.
>
> However, the curr maybe not the left most dl task in the rb tree any
> more after this immediately replenished and reschedule is needed.
> Start high-res preemption tick for this upcoming rescheduled dl task
> is not correct.
>
So, the task that is going to preempt curr is picked by
pick_next_task_dl(), that correctly starts the hrtick for this new task.
Maybe you can add more information about what you are seeing? A callpath
maybe?
Thanks,
- Juri
> This patch fix it by not starting high-res preemption tick for a
> non-running dl task.
>
> Signed-off-by: Wanpeng Li <wanpeng...@linux.intel.com>
> ---
> kernel/sched/deadline.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 56674f6..2a6a5bb 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -1090,7 +1090,8 @@ static void task_tick_dl(struct rq *rq, struct
> task_struct *p, int queued)
> {
> update_curr_dl(rq);
>
> - if (hrtick_enabled(rq) && queued && p->dl.runtime > 0)
> + if (hrtick_enabled(rq) && queued && p->dl.runtime > 0 &&
> + is_leftmost(p, &rq->dl))
> start_hrtick_dl(rq, p);
> }
>
>
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