[RFC][PATCH 5/6] sched: Add flags to the switch{ing,ed}_{to,from}() methods

[Peter Zijlstra <peterz@infradead.org>]

... and remove switched_to_scx(), since all methods are now optional.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/sched/core.c      |    8 ++++----
 kernel/sched/deadline.c  |    4 ++--
 kernel/sched/ext.c       |    6 ++----
 kernel/sched/fair.c      |    4 ++--
 kernel/sched/idle.c      |    2 +-
 kernel/sched/rt.c        |    4 ++--
 kernel/sched/sched.h     |    8 ++++----
 kernel/sched/stop_task.c |    2 +-
 8 files changed, 18 insertions(+), 20 deletions(-)

--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -10531,7 +10531,7 @@ struct sched_change_ctx sched_change_beg
 	lockdep_assert_rq_held(rq);
 
 	if ((flags & DEQUEUE_CLASS) && p->sched_class->switching_from)
-		p->sched_class->switching_from(rq, p);
+		p->sched_class->switching_from(rq, p, flags);
 
 	struct sched_change_ctx ctx = {
 		.p = p,
@@ -10546,7 +10546,7 @@ struct sched_change_ctx sched_change_beg
 		put_prev_task(rq, p);
 
 	if ((flags & DEQUEUE_CLASS) && p->sched_class->switched_from)
-		p->sched_class->switched_from(rq, p);
+		p->sched_class->switched_from(rq, p, flags);
 
 	return ctx;
 }
@@ -10559,7 +10559,7 @@ void sched_change_end(struct sched_chang
 	lockdep_assert_rq_held(rq);
 
 	if ((ctx.flags & ENQUEUE_CLASS) && p->sched_class->switching_to)
-		p->sched_class->switching_to(rq, p);
+		p->sched_class->switching_to(rq, p, ctx.flags);
 
 	if (ctx.queued)
 		enqueue_task(rq, p, ctx.flags | ENQUEUE_NOCLOCK);
@@ -10567,5 +10567,5 @@ void sched_change_end(struct sched_chang
 		set_next_task(rq, p);
 
 	if ((ctx.flags & ENQUEUE_CLASS) && p->sched_class->switched_to)
-		p->sched_class->switched_to(rq, p);
+		p->sched_class->switched_to(rq, p, ctx.flags);
 }
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2968,7 +2968,7 @@ void dl_clear_root_domain(struct root_do
 
 #endif /* CONFIG_SMP */
 
-static void switched_from_dl(struct rq *rq, struct task_struct *p)
+static void switched_from_dl(struct rq *rq, struct task_struct *p, int flags)
 {
 	/*
 	 * task_non_contending() can start the "inactive timer" (if the 0-lag
@@ -3022,7 +3022,7 @@ static void switched_from_dl(struct rq *
  * When switching to -deadline, we may overload the rq, then
  * we try to push someone off, if possible.
  */
-static void switched_to_dl(struct rq *rq, struct task_struct *p)
+static void switched_to_dl(struct rq *rq, struct task_struct *p, int flags)
 {
 	if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1)
 		put_task_struct(p);
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -3663,7 +3663,7 @@ static void prio_changed_scx(struct rq *
 {
 }
 
-static void switching_to_scx(struct rq *rq, struct task_struct *p)
+static void switching_to_scx(struct rq *rq, struct task_struct *p, int flags)
 {
 	scx_ops_enable_task(p);
 
@@ -3676,13 +3676,12 @@ static void switching_to_scx(struct rq *
 				 (struct cpumask *)p->cpus_ptr);
 }
 
-static void switched_from_scx(struct rq *rq, struct task_struct *p)
+static void switched_from_scx(struct rq *rq, struct task_struct *p, int flags)
 {
 	scx_ops_disable_task(p);
 }
 
 static void wakeup_preempt_scx(struct rq *rq, struct task_struct *p,int wake_flags) {}
-static void switched_to_scx(struct rq *rq, struct task_struct *p) {}
 
 int scx_check_setscheduler(struct task_struct *p, int policy)
 {
@@ -3971,7 +3970,6 @@ DEFINE_SCHED_CLASS(ext) = {
 
 	.switching_to		= switching_to_scx,
 	.switched_from		= switched_from_scx,
-	.switched_to		= switched_to_scx,
 	.reweight_task		= reweight_task_scx,
 	.prio_changed		= prio_changed_scx,
 
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -13175,12 +13175,12 @@ static void attach_task_cfs_rq(struct ta
 	attach_entity_cfs_rq(se);
 }
 
-static void switched_from_fair(struct rq *rq, struct task_struct *p)
+static void switched_from_fair(struct rq *rq, struct task_struct *p, int flags)
 {
 	detach_task_cfs_rq(p);
 }
 
-static void switched_to_fair(struct rq *rq, struct task_struct *p)
+static void switched_to_fair(struct rq *rq, struct task_struct *p, int flags)
 {
 	SCHED_WARN_ON(p->se.sched_delayed);
 
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -494,7 +494,7 @@ static void task_tick_idle(struct rq *rq
 {
 }
 
-static void switching_to_idle(struct rq *rq, struct task_struct *p)
+static void switching_to_idle(struct rq *rq, struct task_struct *p, int flags)
 {
 	BUG();
 }
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -2420,7 +2420,7 @@ static void rq_offline_rt(struct rq *rq)
  * When switch from the rt queue, we bring ourselves to a position
  * that we might want to pull RT tasks from other runqueues.
  */
-static void switched_from_rt(struct rq *rq, struct task_struct *p)
+static void switched_from_rt(struct rq *rq, struct task_struct *p, int flags)
 {
 	/*
 	 * If there are other RT tasks then we will reschedule
@@ -2451,7 +2451,7 @@ void __init init_sched_rt_class(void)
  * with RT tasks. In this case we try to push them off to
  * other runqueues.
  */
-static void switched_to_rt(struct rq *rq, struct task_struct *p)
+static void switched_to_rt(struct rq *rq, struct task_struct *p, int flags)
 {
 	/*
 	 * If we are running, update the avg_rt tracking, as the running time
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2417,10 +2417,10 @@ struct sched_class {
 	void (*task_fork)(struct task_struct *p);
 	void (*task_dead)(struct task_struct *p);
 
-	void (*switching_from)(struct rq *this_rq, struct task_struct *task);
-	void (*switched_from) (struct rq *this_rq, struct task_struct *task);
-	void (*switching_to)  (struct rq *this_rq, struct task_struct *task);
-	void (*switched_to)   (struct rq *this_rq, struct task_struct *task);
+	void (*switching_from)(struct rq *this_rq, struct task_struct *task, int flags);
+	void (*switched_from) (struct rq *this_rq, struct task_struct *task, int flags);
+	void (*switching_to)  (struct rq *this_rq, struct task_struct *task, int flags);
+	void (*switched_to)   (struct rq *this_rq, struct task_struct *task, int flags);
 
 	void (*reweight_task)(struct rq *this_rq, struct task_struct *task,
 			      const struct load_weight *lw);
--- a/kernel/sched/stop_task.c
+++ b/kernel/sched/stop_task.c
@@ -76,7 +76,7 @@ static void task_tick_stop(struct rq *rq
 {
 }
 
-static void switching_to_stop(struct rq *rq, struct task_struct *p)
+static void switching_to_stop(struct rq *rq, struct task_struct *p, int flags)
 {
 	BUG(); /* its impossible to change to this class */
 }