Messages in this thread Patch in this message | | | From | Kirill Tkhai <> | Subject | [RFC] sched/deadline: Prevent rt_time growth to infinity | Date | Thu, 20 Feb 2014 02:16:00 +0400 |
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Since deadline tasks share rt bandwidth, we must care about bandwidth timer set. Otherwise rt_time may grow up to infinity in update_curr_dl(), if there are no other available RT tasks on top level bandwidth.
I'm going to decide the problem the way below. Almost untested because of I skipped almost all of recent patches which haveto be applied from lkml.
Please say, if I skipped anything in idea. Maybe better put start_top_rt_bandwidth() into set_curr_task_dl()?
--- kernel/sched/deadline.c | 1 + kernel/sched/rt.c | 16 +++++++++++++++- kernel/sched/sched.h | 1 + 3 files changed, 17 insertions(+), 1 deletion(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index ed31ef6..f1d2304 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -720,6 +720,7 @@ void inc_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) inc_dl_deadline(dl_rq, deadline); inc_dl_migration(dl_se, dl_rq); + start_top_rt_bandwidth(rq_of_dl_rq(dl_rq)); } static inline diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 72f9ec7..a187eb8 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -726,7 +726,7 @@ static inline int balance_runtime(struct rt_rq *rt_rq) static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun) { - int i, idle = 1, throttled = 0; + int i, idle = 1, throttled = 0, has_dl_tasks = 0; const struct cpumask *span; span = sched_rt_period_mask(); @@ -781,9 +781,15 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun) if (enqueue) sched_rt_rq_enqueue(rt_rq); + + if (rt_rq == &rq->rt && rq->dl.dl_nr_running) + has_dl_tasks = 1; raw_spin_unlock(&rq->lock); } + if (has_dl_tasks) + return 0; + if (!throttled && (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)) return 1; @@ -1005,6 +1011,10 @@ dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted); } +void start_top_rt_bandwidth(struct rq *rq) +{ + start_rt_bandwidth(&rq->rt.tg->rt_bandwidth); +} #else /* CONFIG_RT_GROUP_SCHED */ static void @@ -1016,6 +1026,10 @@ inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) static inline void dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) {} +void start_top_rt_bandwidth(struct rq *rq) +{ + start_rt_bandwidth(&def_rt_bandwidth); +} #endif /* CONFIG_RT_GROUP_SCHED */ static inline diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 1bf34c2..a20f8f7 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1294,6 +1294,7 @@ static inline void sched_avg_update(struct rq *rq) { } #endif extern void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period); +extern void start_top_rt_bandwidth(struct rq *rq); #ifdef CONFIG_SMP #ifdef CONFIG_PREEMPT
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