Merge tag 'sched-urgent-2026-01-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Ingo Molnar:

 - Fix PELT clock synchronization bug when entering idle

 - Disable the NEXT_BUDDY feature, as during extensive testing
   Mel found that the negatives outweigh the positives

 - Make wakeup preemption less aggressive, which resulted in
   an unreasonable increase in preemption frequency

* tag 'sched-urgent-2026-01-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Revert force wakeup preemption
  sched/fair: Disable scheduler feature NEXT_BUDDY
  sched/fair: Fix pelt clock sync when entering idle

Author: torvalds

kernel/sched/fair.c

@@ -8828,16 +8828,6 @@ static void check_preempt_wakeup_fair(struct rq *rq, struct task_struct *p, int
 	if ((wake_flags & WF_FORK) || pse->sched_delayed)
 		return;
 
-	/*
-	 * If @p potentially is completing work required by current then
-	 * consider preemption.
-	 *
-	 * Reschedule if waker is no longer eligible. */
-	if (in_task() && !entity_eligible(cfs_rq, se)) {
-		preempt_action = PREEMPT_WAKEUP_RESCHED;
-		goto preempt;
-	}
-
 	/* Prefer picking wakee soon if appropriate. */
 	if (sched_feat(NEXT_BUDDY) &&
 	    set_preempt_buddy(cfs_rq, wake_flags, pse, se)) {
@@ -8995,12 +8985,6 @@ pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf
 			goto again;
 	}
 
-	/*
-	 * rq is about to be idle, check if we need to update the
-	 * lost_idle_time of clock_pelt
-	 */
-	update_idle_rq_clock_pelt(rq);
-
 	return NULL;
 }
 

kernel/sched/features.h

@@ -29,7 +29,7 @@ SCHED_FEAT(PREEMPT_SHORT, true)
  * wakeup-preemption), since its likely going to consume data we
  * touched, increases cache locality.
  */
-SCHED_FEAT(NEXT_BUDDY, true)
+SCHED_FEAT(NEXT_BUDDY, false)
 
 /*
  * Allow completely ignoring cfs_rq->next; which can be set from various

kernel/sched/idle.c

@@ -468,6 +468,12 @@ static void set_next_task_idle(struct rq *rq, struct task_struct *next, bool fir
 	scx_update_idle(rq, true, true);
 	schedstat_inc(rq->sched_goidle);
 	next->se.exec_start = rq_clock_task(rq);
+
+	/*
+	 * rq is about to be idle, check if we need to update the
+	 * lost_idle_time of clock_pelt
+	 */
+	update_idle_rq_clock_pelt(rq);
 }
 
 struct task_struct *pick_task_idle(struct rq *rq, struct rq_flags *rf)