Miscellaneous scheduler fixes/cleanups:

- Fix psi_dequeue() for Proxy Execution
   - Fix hrtick() vs. scheduling context bug
   - Fix unfairness caused by stalled tg_load_avg_contrib when the last task migrates out
   - Fix whitespace noise in headers
   - Remove a preempt-disable section in rt_mutex_setprio()
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-urgent-2025-12-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Ingo Molnar:
 "Miscellaneous scheduler fixes/cleanups:

   - Fix psi_dequeue() for Proxy Execution

   - Fix hrtick() vs. scheduling context bug

   - Fix unfairness caused by stalled tg_load_avg_contrib when the last
     task migrates out

   - Fix whitespace noise in headers

   - Remove a preempt-disable section in rt_mutex_setprio()"

* tag 'sched-urgent-2025-12-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Fix psi_dequeue() for Proxy Execution
  sched/fair: Fix unfairness caused by stalled tg_load_avg_contrib when the last task migrates out
  sched/rt: Remove a preempt-disable section in rt_mutex_setprio()
  sched/hrtick: Fix hrtick() vs. scheduling context
  sched/headers: Remove whitespace noise from kernel/sched/sched.h

kernel/sched/core.c

@@ -878,7 +878,7 @@ static enum hrtimer_restart hrtick(struct hrtimer *timer)
 
 	rq_lock(rq, &rf);
 	update_rq_clock(rq);
-	rq->donor->sched_class->task_tick(rq, rq->curr, 1);
+	rq->donor->sched_class->task_tick(rq, rq->donor, 1);
 	rq_unlock(rq, &rf);
 
 	return HRTIMER_NORESTART;
@@ -7360,15 +7360,12 @@ void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task)
 		p->prio = prio;
 	}
 out_unlock:
-	/* Avoid rq from going away on us: */
-	preempt_disable();
+	/* Caller holds task_struct::pi_lock, IRQs are still disabled */
 
 	rq_unpin_lock(rq, &rf);
 	__balance_callbacks(rq);
 	rq_repin_lock(rq, &rf);
 	__task_rq_unlock(rq, p, &rf);
-
-	preempt_enable();
 }
 #endif /* CONFIG_RT_MUTEXES */
 

kernel/sched/fair.c

@@ -4034,6 +4034,9 @@ static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
 	if (child_cfs_rq_on_list(cfs_rq))
 		return false;
 
+	if (cfs_rq->tg_load_avg_contrib)
+		return false;
+
 	return true;
 }
 

kernel/sched/sched.h

@@ -1167,7 +1167,7 @@ struct rq {
 	 * one CPU and if it got migrated afterwards it may decrease
 	 * it on another CPU. Always updated under the runqueue lock:
 	 */
-	unsigned long 		nr_uninterruptible;
+	unsigned long		nr_uninterruptible;
 
 #ifdef CONFIG_SCHED_PROXY_EXEC
 	struct task_struct __rcu	*donor;  /* Scheduling context */

kernel/sched/stats.h

@@ -180,8 +180,13 @@ static inline void psi_dequeue(struct task_struct *p, int flags)
 	 * avoid walking all ancestors twice, psi_task_switch() handles
 	 * TSK_RUNNING and TSK_IOWAIT for us when it moves TSK_ONCPU.
 	 * Do nothing here.
+	 *
+	 * In the SCHED_PROXY_EXECUTION case we may do sleeping
+	 * dequeues that are not followed by a task switch, so check
+	 * TSK_ONCPU is set to ensure the task switch is imminent.
+	 * Otherwise clear the flags as usual.
 	 */
-	if (flags & DEQUEUE_SLEEP)
+	if ((flags & DEQUEUE_SLEEP) && (p->psi_flags & TSK_ONCPU))
 		return;
 
 	/*