Merge branch 'for-6.12-fixes' into for-6.13

Pull sched_ext/for-6.12-fixes to receive 0e7ffff ("scx: Fix raciness in
scx_ops_bypass()"). Planned updates for scx_ops_bypass() depends on it.

Signed-off-by: Tejun Heo <[email protected]>

Author: htejun

Documentation/scheduler/sched-ext.rst

@@ -66,7 +66,7 @@ BPF scheduler and reverts all tasks back to CFS.
 .. code-block:: none
 
     # make -j16 -C tools/sched_ext
-    # tools/sched_ext/scx_simple
+    # tools/sched_ext/build/bin/scx_simple
     local=0 global=3
     local=5 global=24
     local=9 global=44

kernel/sched/core.c

@@ -3518,14 +3518,16 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
  * The caller (fork, wakeup) owns p->pi_lock, ->cpus_ptr is stable.
  */
 static inline
-int select_task_rq(struct task_struct *p, int cpu, int wake_flags)
+int select_task_rq(struct task_struct *p, int cpu, int *wake_flags)
 {
 	lockdep_assert_held(&p->pi_lock);
 
-	if (p->nr_cpus_allowed > 1 && !is_migration_disabled(p))
-		cpu = p->sched_class->select_task_rq(p, cpu, wake_flags);
-	else
+	if (p->nr_cpus_allowed > 1 && !is_migration_disabled(p)) {
+		cpu = p->sched_class->select_task_rq(p, cpu, *wake_flags);
+		*wake_flags |= WF_RQ_SELECTED;
+	} else {
 		cpu = cpumask_any(p->cpus_ptr);
+	}
 
 	/*
 	 * In order not to call set_task_cpu() on a blocking task we need
@@ -3659,6 +3661,8 @@ ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags,
 		rq->nr_uninterruptible--;
 
 #ifdef CONFIG_SMP
+	if (wake_flags & WF_RQ_SELECTED)
+		en_flags |= ENQUEUE_RQ_SELECTED;
 	if (wake_flags & WF_MIGRATED)
 		en_flags |= ENQUEUE_MIGRATED;
 	else
@@ -4120,6 +4124,8 @@ int try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
 	guard(preempt)();
 	int cpu, success = 0;
 
+	wake_flags |= WF_TTWU;
+
 	if (p == current) {
 		/*
 		 * We're waking current, this means 'p->on_rq' and 'task_cpu(p)
@@ -4252,7 +4258,7 @@ int try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
 		 */
 		smp_cond_load_acquire(&p->on_cpu, !VAL);
 
-		cpu = select_task_rq(p, p->wake_cpu, wake_flags | WF_TTWU);
+		cpu = select_task_rq(p, p->wake_cpu, &wake_flags);
 		if (task_cpu(p) != cpu) {
 			if (p->in_iowait) {
 				delayacct_blkio_end(p);
@@ -4793,6 +4799,7 @@ void wake_up_new_task(struct task_struct *p)
 {
 	struct rq_flags rf;
 	struct rq *rq;
+	int wake_flags = WF_FORK;
 
 	raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
 	WRITE_ONCE(p->__state, TASK_RUNNING);
@@ -4807,15 +4814,15 @@ void wake_up_new_task(struct task_struct *p)
 	 */
 	p->recent_used_cpu = task_cpu(p);
 	rseq_migrate(p);
-	__set_task_cpu(p, select_task_rq(p, task_cpu(p), WF_FORK));
+	__set_task_cpu(p, select_task_rq(p, task_cpu(p), &wake_flags));
 #endif
 	rq = __task_rq_lock(p, &rf);
 	update_rq_clock(rq);
 	post_init_entity_util_avg(p);
 
 	activate_task(rq, p, ENQUEUE_NOCLOCK | ENQUEUE_INITIAL);
 	trace_sched_wakeup_new(p);
-	wakeup_preempt(rq, p, WF_FORK);
+	wakeup_preempt(rq, p, wake_flags);
 #ifdef CONFIG_SMP
 	if (p->sched_class->task_woken) {
 		/*