From ad2a3f13b7258a5daaaeb8cff9f835aac468b71d Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 19 Jun 2008 09:06:57 +0200 Subject: [PATCH] sched: rt-group: heirarchy aware throttle The bandwidth throttle code dequeues a group when it runs out of quota, and re-queues it once the period rolls over and the quota gets refreshed. Sadly it failed to take the hierarchy into consideration. Share more of the enqueue/dequeue code with regular task opterations. Also, some operations like sched_setscheduler() can dequeue/enqueue tasks that are in throttled runqueues, we should not inadvertly re-enqueue empty runqueues so check for that. Signed-off-by: Peter Zijlstra Tested-by: Daniel K. Signed-off-by: Ingo Molnar --- kernel/sched_rt.c | 59 ++++++++++++++++++++++++++--------------------- 1 file changed, 33 insertions(+), 26 deletions(-) diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 3432d573205d..837241568d76 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -449,13 +449,19 @@ void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) #endif } -static void enqueue_rt_entity(struct sched_rt_entity *rt_se) +static void __enqueue_rt_entity(struct sched_rt_entity *rt_se) { struct rt_rq *rt_rq = rt_rq_of_se(rt_se); struct rt_prio_array *array = &rt_rq->active; struct rt_rq *group_rq = group_rt_rq(rt_se); - if (group_rq && rt_rq_throttled(group_rq)) + /* + * Don't enqueue the group if its throttled, or when empty. + * The latter is a consequence of the former when a child group + * get throttled and the current group doesn't have any other + * active members. + */ + if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running)) return; list_add_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se)); @@ -464,7 +470,7 @@ static void enqueue_rt_entity(struct sched_rt_entity *rt_se) inc_rt_tasks(rt_se, rt_rq); } -static void dequeue_rt_entity(struct sched_rt_entity *rt_se) +static void __dequeue_rt_entity(struct sched_rt_entity *rt_se) { struct rt_rq *rt_rq = rt_rq_of_se(rt_se); struct rt_prio_array *array = &rt_rq->active; @@ -480,11 +486,10 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se) * Because the prio of an upper entry depends on the lower * entries, we must remove entries top - down. */ -static void dequeue_rt_stack(struct task_struct *p) +static void dequeue_rt_stack(struct sched_rt_entity *rt_se) { - struct sched_rt_entity *rt_se, *back = NULL; + struct sched_rt_entity *back = NULL; - rt_se = &p->rt; for_each_sched_rt_entity(rt_se) { rt_se->back = back; back = rt_se; @@ -492,7 +497,26 @@ static void dequeue_rt_stack(struct task_struct *p) for (rt_se = back; rt_se; rt_se = rt_se->back) { if (on_rt_rq(rt_se)) - dequeue_rt_entity(rt_se); + __dequeue_rt_entity(rt_se); + } +} + +static void enqueue_rt_entity(struct sched_rt_entity *rt_se) +{ + dequeue_rt_stack(rt_se); + for_each_sched_rt_entity(rt_se) + __enqueue_rt_entity(rt_se); +} + +static void dequeue_rt_entity(struct sched_rt_entity *rt_se) +{ + dequeue_rt_stack(rt_se); + + for_each_sched_rt_entity(rt_se) { + struct rt_rq *rt_rq = group_rt_rq(rt_se); + + if (rt_rq && rt_rq->rt_nr_running) + __enqueue_rt_entity(rt_se); } } @@ -506,32 +530,15 @@ static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup) if (wakeup) rt_se->timeout = 0; - dequeue_rt_stack(p); - - /* - * enqueue everybody, bottom - up. - */ - for_each_sched_rt_entity(rt_se) - enqueue_rt_entity(rt_se); + enqueue_rt_entity(rt_se); } static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep) { struct sched_rt_entity *rt_se = &p->rt; - struct rt_rq *rt_rq; update_curr_rt(rq); - - dequeue_rt_stack(p); - - /* - * re-enqueue all non-empty rt_rq entities. - */ - for_each_sched_rt_entity(rt_se) { - rt_rq = group_rt_rq(rt_se); - if (rt_rq && rt_rq->rt_nr_running) - enqueue_rt_entity(rt_se); - } + dequeue_rt_entity(rt_se); } /* -- 2.20.1