linux-kernel - [PATCH 5/6] sched_ext: Remove switch_class

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Message-ID: <20240904080326.1132275-6-tj@kernel.org>
Date: Tue,  3 Sep 2024 22:03:07 -1000
From: Tejun Heo <tj@...nel.org>
To: void@...ifault.com
Cc: kernel-team@...a.com,
	linux-kernel@...r.kernel.org,
	peterz@...radead.org,
	Tejun Heo <tj@...nel.org>
Subject: [PATCH 5/6] sched_ext: Remove switch_class_scx()

Now that put_prev_task_scx() is called with @next on task switches, there's
no reason to use sched_class.switch_class(). Rename switch_class_scx() to
switch_class() and call it from put_prev_task_scx().

Signed-off-by: Tejun Heo <tj@...nel.org>
---
 kernel/sched/ext.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 24bafa649fdb..f0c9823915c6 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -2723,12 +2723,10 @@ preempt_reason_from_class(const struct sched_class *class)
 	return SCX_CPU_PREEMPT_UNKNOWN;
 }
 
-static void switch_class_scx(struct rq *rq, struct task_struct *next)
+static void switch_class(struct rq *rq, struct task_struct *next)
 {
 	const struct sched_class *next_class = next->sched_class;
 
-	if (!scx_enabled())
-		return;
 #ifdef CONFIG_SMP
 	/*
 	 * Pairs with the smp_load_acquire() issued by a CPU in
@@ -2808,6 +2806,9 @@ static void put_prev_task_scx(struct rq *rq, struct task_struct *p,
 			do_enqueue_task(rq, p, 0, -1);
 		}
 	}
+
+	if (next && next->sched_class != &ext_sched_class)
+		switch_class(rq, next);
 }
 
 static struct task_struct *first_local_task(struct rq *rq)
@@ -3591,8 +3592,6 @@ DEFINE_SCHED_CLASS(ext) = {
 	.put_prev_task		= put_prev_task_scx,
 	.set_next_task		= set_next_task_scx,
 
-	.switch_class		= switch_class_scx,
-
 #ifdef CONFIG_SMP
 	.select_task_rq		= select_task_rq_scx,
 	.task_woken		= task_woken_scx,
-- 
2.46.0