[tip: sched/core] sched/smp: Always define rq->hrtick_csd

[tip-bot2 for Ingo Molnar]

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     a1416303d108befb4e2b62c863ae1defe4eb1ba3
Gitweb:        https://git.kernel.org/tip/a1416303d108befb4e2b62c863ae1defe4eb1ba3
Author:        Ingo Molnar <mingo@xxxxxxxxxx>
AuthorDate:    Wed, 28 May 2025 10:09:03 +02:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Fri, 13 Jun 2025 08:47:19 +02:00

sched/smp: Always define rq->hrtick_csd

Simplify the scheduler by making CONFIG_SMP=y data structure
of rq->hrtick_csd unconditional.

Adjust hrtick_start() accordingly, which was split due to the
::hrtick_csd asymmetry and use the SMP version there too.

Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Shrikanth Hegde <sshegde@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Valentin Schneider <vschneid@xxxxxxxxxx>
Cc: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20250528080924.2273858-23-mingo@xxxxxxxxxx
---
 kernel/sched/core.c  | 23 -----------------------
 kernel/sched/sched.h |  2 --
 2 files changed, 25 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 9fc44f4..c155ee0 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -851,8 +851,6 @@ static enum hrtimer_restart hrtick(struct hrtimer *timer)
 	return HRTIMER_NORESTART;
 }
 
-#ifdef CONFIG_SMP
-
 static void __hrtick_restart(struct rq *rq)
 {
 	struct hrtimer *timer = &rq->hrtick_timer;
@@ -897,30 +895,9 @@ void hrtick_start(struct rq *rq, u64 delay)
 		smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd);
 }
 
-#else /* !CONFIG_SMP: */
-/*
- * Called to set the hrtick timer state.
- *
- * called with rq->lock held and IRQs disabled
- */
-void hrtick_start(struct rq *rq, u64 delay)
-{
-	/*
-	 * Don't schedule slices shorter than 10000ns, that just
-	 * doesn't make sense. Rely on vruntime for fairness.
-	 */
-	delay = max_t(u64, delay, 10000LL);
-	hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay),
-		      HRTIMER_MODE_REL_PINNED_HARD);
-}
-
-#endif /* !CONFIG_SMP */
-
 static void hrtick_rq_init(struct rq *rq)
 {
-#ifdef CONFIG_SMP
 	INIT_CSD(&rq->hrtick_csd, __hrtick_start, rq);
-#endif
 	hrtimer_setup(&rq->hrtick_timer, hrtick, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
 }
 #else /* !CONFIG_SCHED_HRTICK: */
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 7a7ebc2..3e7151e 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1219,9 +1219,7 @@ struct rq {
 	long			calc_load_active;
 
 #ifdef CONFIG_SCHED_HRTICK
-#ifdef CONFIG_SMP
 	call_single_data_t	hrtick_csd;
-#endif
 	struct hrtimer		hrtick_timer;
 	ktime_t			hrtick_time;
 #endif