Messages in this thread | | | Subject | Re: [PATCH]sched/rt.c: leaf_rt_rq_list contains empty queues. Fix it | From | Steven Rostedt <> | Date | Fri, 21 Sep 2012 10:31:30 -0400 |
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On Fri, 2012-09-21 at 17:35 +0400, Kirill Tkhai wrote: > Function __enqueue_rt_entity() adds an empty queue to leaf_rt_rq_list. > > So, pick_next_highest_task_rt() picks empty queues. Fix it.
Do you have an example where this breaks?
> > Signed-off-by: Kirill Tkhai <tkhai@yandex.ru> > --- > 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..b07edb9 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) > list_add_leaf_rt_rq(rt_rq);
Note, the list_add_leaf_rt_rq() is called when the first task is queued up. The function here is __enqueue_rt_entity(), which will increment rt_rq->rt_nr_running. If this is the first entry we add the queue now, as the __dequeue_rt_entity() does the list_del_leaf_rt_rq() when it goes to zero.
-- Steve
> > if (head)
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