sched: deadline: Add some helper variables to cleanup deadline logic

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@noisy.programming.kicks-ass.net/

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260512025635.2840817-3-jstultz@google.com

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 6ef5a808e13e09c9fad6cb639467a3bb9a9da6b4..0b7ac4c1279704a21cfb53abab6d2843045af919 100644 (file)
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2484,7 +2484,10 @@ 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
@@ -2497,14 +2500,14 @@ 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)) {
                /*
@@ -2516,7 +2519,7 @@ 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));
@@ -2525,20 +2528,20 @@ 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))
                return;
 
-       if (!task_current(rq, p) && !p->dl.dl_throttled && p->nr_cpus_allowed > 1)
+       if (!task_current(rq, p) && !dl_se->dl_throttled && p->nr_cpus_allowed > 1)
                enqueue_pushable_dl_task(rq, p);
 }
 
@@ -2835,7 +2838,7 @@ 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);
@@ -2845,7 +2848,7 @@ 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);
 }