[PATCH v27 03/10] sched: deadline: Add some helper variables to cleanup deadline logic

[John Stultz]

As part of an improvement to handling pushable deadline tasks,
Peter suggested this cleanup[1], to use helper values for
dl_entity and dl_rq in the enqueue_task_dl() and
put_prev_task_dl() functions. There should be no functional
change from this patch.

To make sure this cleanup change doesn't obscure later logic
changes, I've split it into its own patch.

[1]: https://lore.kernel.org/lkml/20260304095123.GP606826@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/

Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: John Stultz <jstultz@xxxxxxxxxx>
---
Cc: Joel Fernandes <joelagnelf@xxxxxxxxxx>
Cc: Qais Yousef <qyousef@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
Cc: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Cc: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Cc: Valentin Schneider <vschneid@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ben Segall <bsegall@xxxxxxxxxx>
Cc: Zimuzo Ezeozue <zezeozue@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Waiman Long <longman@xxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Cc: Metin Kaya <Metin.Kaya@xxxxxxx>
Cc: Xuewen Yan <xuewen.yan94@xxxxxxxxx>
Cc: K Prateek Nayak <kprateek.nayak@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Cc: Suleiman Souhlal <suleiman@xxxxxxxxxx>
Cc: kuyo chang <kuyo.chang@xxxxxxxxxxxx>
Cc: hupu <hupu.gm@xxxxxxxxx>
Cc: kernel-team@xxxxxxxxxxx
---
 kernel/sched/deadline.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 7352506208287..60ccb492c4427 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2295,7 +2295,10 @@ static void dequeue_dl_entity(struct sched_dl_entity *dl_se, int flags)
 
 static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
 {
-	if (is_dl_boosted(&p->dl)) {
+	struct sched_dl_entity *dl_se = &p->dl;
+	struct dl_rq *dl_rq = &rq->dl;
+
+	if (is_dl_boosted(dl_se)) {
 		/*
 		 * Because of delays in the detection of the overrun of a
 		 * thread's runtime, it might be the case that a thread
@@ -2308,14 +2311,14 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
 		 *
 		 * In this case, the boost overrides the throttle.
 		 */
-		if (p->dl.dl_throttled) {
+		if (dl_se->dl_throttled) {
 			/*
 			 * The replenish timer needs to be canceled. No
 			 * problem if it fires concurrently: boosted threads
 			 * are ignored in dl_task_timer().
 			 */
-			cancel_replenish_timer(&p->dl);
-			p->dl.dl_throttled = 0;
+			cancel_replenish_timer(dl_se);
+			dl_se->dl_throttled = 0;
 		}
 	} else if (!dl_prio(p->normal_prio)) {
 		/*
@@ -2327,7 +2330,7 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
 		 * being boosted again with no means to replenish the runtime and clear
 		 * the throttle.
 		 */
-		p->dl.dl_throttled = 0;
+		dl_se->dl_throttled = 0;
 		if (!(flags & ENQUEUE_REPLENISH))
 			printk_deferred_once("sched: DL de-boosted task PID %d: REPLENISH flag missing\n",
 					     task_pid_nr(p));
@@ -2336,14 +2339,14 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
 	}
 
 	check_schedstat_required();
-	update_stats_wait_start_dl(dl_rq_of_se(&p->dl), &p->dl);
+	update_stats_wait_start_dl(dl_rq, dl_se);
 
 	if (p->on_rq == TASK_ON_RQ_MIGRATING)
 		flags |= ENQUEUE_MIGRATING;
 
-	enqueue_dl_entity(&p->dl, flags);
+	enqueue_dl_entity(dl_se, flags);
 
-	if (dl_server(&p->dl))
+	if (dl_server(dl_se))
 		return;
 
 	if (task_is_blocked(p))
@@ -2646,7 +2649,7 @@ static void put_prev_task_dl(struct rq *rq, struct task_struct *p, struct task_s
 	struct sched_dl_entity *dl_se = &p->dl;
 	struct dl_rq *dl_rq = &rq->dl;
 
-	if (on_dl_rq(&p->dl))
+	if (on_dl_rq(dl_se))
 		update_stats_wait_start_dl(dl_rq, dl_se);
 
 	update_curr_dl(rq);
@@ -2656,7 +2659,7 @@ static void put_prev_task_dl(struct rq *rq, struct task_struct *p, struct task_s
 	if (task_is_blocked(p))
 		return;
 
-	if (on_dl_rq(&p->dl) && p->nr_cpus_allowed > 1)
+	if (on_dl_rq(dl_se) && p->nr_cpus_allowed > 1)
 		enqueue_pushable_dl_task(rq, p);
 }
 
-- 
2.53.0.1213.gd9a14994de-goog