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sched: fix goto retry in pick_next_task_rt() 

looking at it one more time:

(1) it looks to me that there is no need to call
sched_rt_ratio_exceeded() from pick_next_rt_entity()

- [ for CONFIG_FAIR_GROUP_SCHED ] queues with rt_rq->rt_throttled are
not within this 'tree-like hierarchy' (or whatever we should call it
:-)

- there is also no need to re-check 'rt_rq->rt_time > ratio' at this
point as 'rt_rq->rt_time' couldn't have been increased since the last
call to update_curr_rt() (which obviously calls
sched_rt_ratio_esceeded())
well, it might be that 'ratio' for this rt_rq has been re-configured
(and the period over which this rt_rq was active has not yet been
finished)... but I don't think we should really take this into
account.

(2) now pick_next_rt_entity() must never return NULL, so let's change
pick_next_task_rt() accordingly.

Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Dmitry Adamushko 2008-01-25 21:08:34 +01:00 committed by Ingo Molnar
parent e118adef23
commit 326587b840
1 changed files with 2 additions and 7 deletions
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9
kernel/sched_rt.c
View File

@ -476,15 +476,12 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
struct list_head *queue; struct list_head *queue;
int idx; int idx;
if (sched_rt_ratio_exceeded(rt_rq))
goto out;
idx = sched_find_first_bit(array->bitmap); idx = sched_find_first_bit(array->bitmap);
BUG_ON(idx >= MAX_RT_PRIO); BUG_ON(idx >= MAX_RT_PRIO);
queue = array->queue + idx; queue = array->queue + idx;
next = list_entry(queue->next, struct sched_rt_entity, run_list); next = list_entry(queue->next, struct sched_rt_entity, run_list);
out:
return next; return next;
} }
@ -494,7 +491,6 @@ static struct task_struct *pick_next_task_rt(struct rq *rq)
struct task_struct *p; struct task_struct *p;
struct rt_rq *rt_rq; struct rt_rq *rt_rq;
retry:
rt_rq = &rq->rt; rt_rq = &rq->rt;
if (unlikely(!rt_rq->rt_nr_running)) if (unlikely(!rt_rq->rt_nr_running))
@ -505,8 +501,7 @@ static struct task_struct *pick_next_task_rt(struct rq *rq)
do { do {
rt_se = pick_next_rt_entity(rq, rt_rq); rt_se = pick_next_rt_entity(rq, rt_rq);
if (unlikely(!rt_se)) BUG_ON(!rt_se);
goto retry;
rt_rq = group_rt_rq(rt_se); rt_rq = group_rt_rq(rt_se);
} while (rt_rq); } while (rt_rq);