Hi Juri, On Mon, Apr 20, 2015 at 11:27:22AM +0100, Juri Lelli wrote: >Hi, > >On 06/04/2015 09:53, Wanpeng Li wrote: >> pull_dl_task can drop (and re-acquire) rq->lock, this means a stop task >> can slip in, in which case we need to reschedule. This patch add the >> reschedule when the scenario occurs. >> > >Ok, I guess it can happen. Doesn't RT have the same problem? It seems that >it also has to deal with DL tasks slipping in, right?
Yeah, I will send another patch to handle RT class in the v2 patchset. :) Regards, Wanpeng Li > >Thanks, > >- Juri > >> Signed-off-by: Wanpeng Li <wanpeng...@linux.intel.com> >> --- >> kernel/sched/deadline.c | 16 +++++++++++++++- >> 1 file changed, 15 insertions(+), 1 deletion(-) >> >> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c >> index b8b9355..844da0f 100644 >> --- a/kernel/sched/deadline.c >> +++ b/kernel/sched/deadline.c >> @@ -1739,7 +1739,13 @@ static void switched_from_dl(struct rq *rq, struct >> task_struct *p) >> if (!task_on_rq_queued(p) || rq->dl.dl_nr_running) >> return; >> >> - if (pull_dl_task(rq)) >> + /* >> + * pull_dl_task() can drop (and re-acquire) rq->lock; this >> + * means a stop task can slip in, in which case we need to >> + * reschedule. >> + */ >> + if (pull_dl_task(rq) || >> + (rq->stop && task_on_rq_queued(rq->stop))) >> resched_curr(rq); >> } >> >> @@ -1786,6 +1792,14 @@ static void prio_changed_dl(struct rq *rq, struct >> task_struct *p, >> pull_dl_task(rq); >> >> /* >> + * pull_dl_task() can drop (and re-acquire) rq->lock; this >> + * means a stop task can slip in, in which case we need to >> + * reschedule. >> + */ >> + if (rq->stop && task_on_rq_queued(rq->stop)) >> + resched_curr(rq); >> + >> + /* >> * If we now have a earlier deadline task than p, >> * then reschedule, provided p is still on this >> * runqueue. >> -- 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/
