From 98b0a857805080db04f50b8c71438c9c369ef0b3 Mon Sep 17 00:00:00 2001 From: Juri Lelli Date: Fri, 5 Aug 2016 16:07:55 +0100 Subject: [PATCH] sched/deadline: Remove useless parameter from setup_new_dl_entity() setup_new_dl_entity() takes two parameters, but it only actually uses one of them, under a different name, to setup a new dl_entity, after: 2f9f3fdc928 "sched/deadline: Remove dl_new from struct sched_dl_entity" as we currently do: setup_new_dl_entity(&p->dl, &p->dl) However, before Luca's change we were doing: setup_new_dl_entity(dl_se, pi_se) in update_dl_entity() for a dl_se->new entity: we were using pi_se's parameters (the potential PI donor) for setting up a new entity. This change removes the useless second parameter of setup_new_dl_entity(). While we are at it we also optimize things further calling setup_new_dl_ entity() only for already queued tasks, since (as pointed out by Xunlei) we already do the very same update at tasks wakeup time anyway. By doing so, we don't need to worry about a potential PI donor anymore, as rt_mutex_setprio() takes care of that already for us. Signed-off-by: Juri Lelli Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Steven Rostedt Cc: Linus Torvalds Cc: Luca Abeni Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Xunlei Pang Link: http://lkml.kernel.org/r/1470409675-20935-1-git-send-email-juri.lelli@arm.com Signed-off-by: Ingo Molnar --- kernel/sched/deadline.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 1ce8867283dc..d091f4a95416 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -346,12 +346,12 @@ static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p, * one, and to (try to!) reconcile itself with its own scheduling * parameters. */ -static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se, - struct sched_dl_entity *pi_se) +static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se) { struct dl_rq *dl_rq = dl_rq_of_se(dl_se); struct rq *rq = rq_of_dl_rq(dl_rq); + WARN_ON(dl_se->dl_boosted); WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline)); /* @@ -367,8 +367,8 @@ static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se, * future; in fact, we must consider execution overheads (time * spent on hardirq context, etc.). */ - dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline; - dl_se->runtime = pi_se->dl_runtime; + dl_se->deadline = rq_clock(rq) + dl_se->dl_deadline; + dl_se->runtime = dl_se->dl_runtime; } /* @@ -1723,10 +1723,20 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p) */ static void switched_to_dl(struct rq *rq, struct task_struct *p) { + + /* If p is not queued we will update its parameters at next wakeup. */ + if (!task_on_rq_queued(p)) + return; + + /* + * If p is boosted we already updated its params in + * rt_mutex_setprio()->enqueue_task(..., ENQUEUE_REPLENISH), + * p's deadline being now already after rq_clock(rq). + */ if (dl_time_before(p->dl.deadline, rq_clock(rq))) - setup_new_dl_entity(&p->dl, &p->dl); + setup_new_dl_entity(&p->dl); - if (task_on_rq_queued(p) && rq->curr != p) { + if (rq->curr != p) { #ifdef CONFIG_SMP if (tsk_nr_cpus_allowed(p) > 1 && rq->dl.overloaded) queue_push_tasks(rq); -- 2.39.5