Re: [PATCH]sched/rt.c: leaf_rt_rq_list contains empty queues. Fix it

From: Steven Rostedt
Date: Fri Sep 21 2012 - 10:32:39 EST


On Fri, 2012-09-21 at 18:21 +0400, Kirill Tkhai wrote:
> Second version. Add every not empty queue once. The patch:
>
> Function __enqueue_rt_entity() adds an empty queue to leaf_rt_rq_list.
>
> So, pick_next_highest_task_rt() picks empty queues. Fix it.
>
> Signed-off-by: Kirill Tkhai <tkhai@xxxxxxxxx>
> ---
> kernel/sched/rt.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
> index 944cb68..97a0954 100644
> --- a/kernel/sched/rt.c
> +++ b/kernel/sched/rt.c
> @@ -1103,7 +1103,7 @@ static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head)
> if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running))
> return;
>
> - if (!rt_rq->rt_nr_running)
> + if (rt_rq->rt_nr_running == 1)
> list_add_leaf_rt_rq(rt_rq);

Again, the rt_nr_running hasn't been incremented yet. This patch will
add it when the rq gets a second task.

-- Steve

>
> if (head)


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