linux-kernel - [PATCH 3/4] Remove dl

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Date:	Mon, 22 Feb 2016 11:57:04 +0100
From:	Luca Abeni <luca.abeni@...tn.it>
To:	Juri Lelli <juri.lelli@....com>
Cc:	rostedt@...dmis.org, linux-kernel@...r.kernel.org,
	peterz@...radead.org, mingo@...hat.com, vincent.guittot@...aro.org,
	wanpeng.li@...mail.com, Luca Abeni <luca.abeni@...tn.it>
Subject: [PATCH 3/4] Remove dl_new

switched_to_dl() can be used instead
---
 kernel/sched/core.c     |  1 -
 kernel/sched/deadline.c | 28 +++++-----------------------
 2 files changed, 5 insertions(+), 24 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5dc12db..4246b1b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2183,7 +2183,6 @@ void __dl_clear_params(struct task_struct *p)
 	dl_se->dl_bw = 0;
 
 	dl_se->dl_throttled = 0;
-	dl_se->dl_new = 1;
 	dl_se->dl_yielded = 0;
 }
 
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 959e7b7..12cb934 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -355,8 +355,6 @@ 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_new || dl_se->dl_throttled);
-
 	/*
 	 * We use the regular wall clock time to set deadlines in the
 	 * future; in fact, we must consider execution overheads (time
@@ -364,7 +362,6 @@ static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se,
 	 */
 	dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
 	dl_se->runtime = pi_se->dl_runtime;
-	dl_se->dl_new = 0;
 }
 
 /*
@@ -503,15 +500,6 @@ static void update_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);
 
-	/*
-	 * The arrival of a new instance needs special treatment, i.e.,
-	 * the actual scheduling parameters have to be "renewed".
-	 */
-	if (dl_se->dl_new) {
-		setup_new_dl_entity(dl_se, pi_se);
-		return;
-	}
-
 	if (dl_time_before(dl_se->deadline, rq_clock(rq)) ||
 	    dl_entity_overflow(dl_se, pi_se, rq_clock(rq))) {
 		dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
@@ -608,16 +596,6 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
 	}
 
 	/*
-	 * This is possible if switched_from_dl() raced against a running
-	 * callback that took the above !dl_task() path and we've since then
-	 * switched back into SCHED_DEADLINE.
-	 *
-	 * There's nothing to do except drop our task reference.
-	 */
-	if (dl_se->dl_new)
-		goto unlock;
-
-	/*
 	 * The task might have been boosted by someone else and might be in the
 	 * boosting/deboosting path, its not throttled.
 	 */
@@ -920,7 +898,7 @@ enqueue_dl_entity(struct sched_dl_entity *dl_se,
 	 * parameters of the task might need updating. Otherwise,
 	 * we want a replenishment of its runtime.
 	 */
-	if (dl_se->dl_new || flags & ENQUEUE_WAKEUP)
+	if (flags & ENQUEUE_WAKEUP)
 		update_dl_entity(dl_se, pi_se);
 	else if (flags & ENQUEUE_REPLENISH)
 		replenish_dl_entity(dl_se, pi_se);
@@ -1738,6 +1716,10 @@ 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->dl.deadline <= rq_clock(rq)) {
+		setup_new_dl_entity(&p->dl, &p->dl);
+	}
+
 	__dl_add_ac(rq, p->dl.dl_bw);
 	if (task_on_rq_queued(p) && rq->curr != p) {
 #ifdef CONFIG_SMP
-- 
2.5.0