Messages in this thread Patch in this message |  | | From | Kirill Tkhai <> | Subject | Re: sched: hang in migrate_swap | Date | Thu, 10 Apr 2014 17:38:36 +0400 |
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10.04.2014, 11:00, "Michael wang" <wangyun@linux.vnet.ibm.com>: > On 04/10/2014 11:31 AM, Sasha Levin wrote: > [snip] > >> I'd like to re-open this issue. It seems that something broke and I'm >> now seeing the same issues that have gone away 2 months with this patch >> again. > > A new mechanism has been designed to move the priority checking inside > idle_balance(), including Kirill who is the designer ;-)
Not sure, it's connected with my patch. But looks like, we forgot exactly stop class. Maybe this will help?
[PATCH] sched: Checking for stop task appearance when balancing happens
Just do it, like we do for other higher priority classes...
Signed-off-by: Kirill Tkhai <tkhai@yandex.ru> --- kernel/sched/deadline.c | 11 ++++++++++- kernel/sched/fair.c | 3 ++- kernel/sched/rt.c | 7 ++++--- 3 files changed, 16 insertions(+), 5 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 27ef409..b080957 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1021,8 +1021,17 @@ struct task_struct *pick_next_task_dl(struct rq *rq, struct task_struct *prev) dl_rq = &rq->dl; - if (need_pull_dl_task(rq, prev)) + if (need_pull_dl_task(rq, prev)) { pull_dl_task(rq); + /* + * pull_rt_task() can drop (and re-acquire) rq->lock; this + * means a stop task can slip in, in which case we need to + * re-start task selection. + */ + if (rq->stop && rq->stop->on_rq) + return RETRY_TASK; + } + /* * When prev is DL, we may throttle it in put_prev_task(). * So, we update time before we check for dl_nr_running. diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 7e9bd0b..c50275b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6727,7 +6727,8 @@ static int idle_balance(struct rq *this_rq) out: /* Is there a task of a high priority class? */ if (this_rq->nr_running != this_rq->cfs.h_nr_running && - (this_rq->dl.dl_nr_running || + ((this_rq->stop && this_rq->stop->on_rq) || + this_rq->dl.dl_nr_running || (this_rq->rt.rt_nr_running && !rt_rq_throttled(&this_rq->rt)))) pulled_task = -1; diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index d8cdf16..bd2267a 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1362,10 +1362,11 @@ pick_next_task_rt(struct rq *rq, struct task_struct *prev) pull_rt_task(rq); /* * pull_rt_task() can drop (and re-acquire) rq->lock; this - * means a dl task can slip in, in which case we need to - * re-start task selection. + * means a dl or stop task can slip in, in which case we need + * to re-start task selection. */ - if (unlikely(rq->dl.dl_nr_running)) + if (unlikely((rq->stop && rq->stop->on_rq) || + rq->dl.dl_nr_running)) return RETRY_TASK; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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