linux-kernel - [RFC PATCH 1/9] sched/deadline: Do not access dl

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Message-ID: <20250605071412.139240-2-yurand2000@gmail.com>
Date: Thu,  5 Jun 2025 09:14:04 +0200
From: Yuri Andriaccio <yurand2000@...il.com>
To: Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Juri Lelli <juri.lelli@...hat.com>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Dietmar Eggemann <dietmar.eggemann@....com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Ben Segall <bsegall@...gle.com>,
	Mel Gorman <mgorman@...e.de>,
	Valentin Schneider <vschneid@...hat.com>
Cc: linux-kernel@...r.kernel.org,
	Luca Abeni <luca.abeni@...tannapisa.it>,
	Yuri Andriaccio <yuri.andriaccio@...tannapisa.it>
Subject: [RFC PATCH 1/9] sched/deadline: Do not access dl_se->rq directly

From: luca abeni <luca.abeni@...tannapisa.it>

Make deadline.c code access the runqueue of a scheduling entity saved in the
sched_dl_entity data structure. This allows future patches to save different
runqueues in sched_dl_entity other than the global runqueues.

Signed-off-by: luca abeni <luca.abeni@...tannapisa.it>
---
 kernel/sched/deadline.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index ad45a8fea..26cd0c559 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -935,7 +935,7 @@ static void replenish_dl_entity(struct sched_dl_entity *dl_se)
 	 * and arm the defer timer.
 	 */
 	if (dl_se->dl_defer && !dl_se->dl_defer_running &&
-	    dl_time_before(rq_clock(dl_se->rq), dl_se->deadline - dl_se->runtime)) {
+	    dl_time_before(rq_clock(rq), dl_se->deadline - dl_se->runtime)) {
 		if (!is_dl_boosted(dl_se) && dl_se->server_has_tasks(dl_se)) {
 
 			/*
@@ -1244,11 +1244,11 @@ static enum hrtimer_restart dl_server_timer(struct hrtimer *timer, struct sched_
 			 * of time. The dl_server_min_res serves as a limit to avoid
 			 * forwarding the timer for a too small amount of time.
 			 */
-			if (dl_time_before(rq_clock(dl_se->rq),
+			if (dl_time_before(rq_clock(rq),
 					   (dl_se->deadline - dl_se->runtime - dl_server_min_res))) {
 
 				/* reset the defer timer */
-				fw = dl_se->deadline - rq_clock(dl_se->rq) - dl_se->runtime;
+				fw = dl_se->deadline - rq_clock(rq) - dl_se->runtime;
 
 				hrtimer_forward_now(timer, ns_to_ktime(fw));
 				return HRTIMER_RESTART;
@@ -1259,7 +1259,7 @@ static enum hrtimer_restart dl_server_timer(struct hrtimer *timer, struct sched_
 
 		enqueue_dl_entity(dl_se, ENQUEUE_REPLENISH);
 
-		if (!dl_task(dl_se->rq->curr) || dl_entity_preempt(dl_se, &dl_se->rq->curr->dl))
+		if (!dl_task(rq->curr) || dl_entity_preempt(dl_se, &rq->curr->dl))
 			resched_curr(rq);
 
 		__push_dl_task(rq, rf);
@@ -1527,7 +1527,7 @@ static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64
 
 		hrtimer_try_to_cancel(&dl_se->dl_timer);
 
-		replenish_dl_new_period(dl_se, dl_se->rq);
+		replenish_dl_new_period(dl_se, rq);
 
 		/*
 		 * Not being able to start the timer seems problematic. If it could not
@@ -1640,12 +1640,12 @@ void dl_server_update(struct sched_dl_entity *dl_se, s64 delta_exec)
 {
 	/* 0 runtime = fair server disabled */
 	if (dl_se->dl_runtime)
-		update_curr_dl_se(dl_se->rq, dl_se, delta_exec);
+		update_curr_dl_se(rq_of_dl_se(dl_se), dl_se, delta_exec);
 }
 
 void dl_server_start(struct sched_dl_entity *dl_se)
 {
-	struct rq *rq = dl_se->rq;
+	struct rq *rq;
 
 	/*
 	 * XXX: the apply do not work fine at the init phase for the
@@ -1656,9 +1656,9 @@ void dl_server_start(struct sched_dl_entity *dl_se)
 		u64 runtime =  50 * NSEC_PER_MSEC;
 		u64 period = 1000 * NSEC_PER_MSEC;
 
+		dl_se->dl_server = 1;
 		dl_server_apply_params(dl_se, runtime, period, 1);
 
-		dl_se->dl_server = 1;
 		dl_se->dl_defer = 1;
 		setup_new_dl_entity(dl_se);
 	}
@@ -1668,8 +1668,9 @@ void dl_server_start(struct sched_dl_entity *dl_se)
 
 	dl_se->dl_server_active = 1;
 	enqueue_dl_entity(dl_se, ENQUEUE_WAKEUP);
-	if (!dl_task(dl_se->rq->curr) || dl_entity_preempt(dl_se, &rq->curr->dl))
-		resched_curr(dl_se->rq);
+			rq = rq_of_dl_se(dl_se);
+	if (!dl_task(rq->curr) || dl_entity_preempt(dl_se, &rq->curr->dl))
+		resched_curr(rq);
 }
 
 void dl_server_stop(struct sched_dl_entity *dl_se)
@@ -1712,7 +1713,7 @@ int dl_server_apply_params(struct sched_dl_entity *dl_se, u64 runtime, u64 perio
 {
 	u64 old_bw = init ? 0 : to_ratio(dl_se->dl_period, dl_se->dl_runtime);
 	u64 new_bw = to_ratio(period, runtime);
-	struct rq *rq = dl_se->rq;
+	struct rq *rq = rq_of_dl_se(dl_se);
 	int cpu = cpu_of(rq);
 	struct dl_bw *dl_b;
 	unsigned long cap;
@@ -1789,7 +1790,7 @@ static enum hrtimer_restart inactive_task_timer(struct hrtimer *timer)
 		p = dl_task_of(dl_se);
 		rq = task_rq_lock(p, &rf);
 	} else {
-		rq = dl_se->rq;
+		rq = rq_of_dl_se(dl_se);
 		rq_lock(rq, &rf);
 	}
 
-- 
2.49.0