From: Tejun Heo <tj@kernel.org>
Date: Mon, 9 Sep 2024 23:40:44 +0000 (-1000)
Subject: sched_ext: Don't trigger ops.quiescent/runnable() on migrations
X-Git-Tag: v6.12-rc1~111^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=513ed0c7ccc103c2ff668154854ec410729a3170;p=thirdparty%2Flinux.git

sched_ext: Don't trigger ops.quiescent/runnable() on migrations

A task moving across CPUs should not trigger quiescent/runnable task state
events as the task is staying runnable the whole time and just stopping and
then starting on different CPUs. Suppress quiescent/runnable task state
events if task_on_rq_migrating().

Signed-off-by: Tejun Heo <tj@kernel.org>
Suggested-by: David Vernet <void@manifault.com>
Cc: Daniel Hodges <hodges.daniel.scott@gmail.com>
Cc: Changwoo Min <multics69@gmail.com>
Cc: Andrea Righi <andrea.righi@linux.dev>
Cc: Dan Schatzberg <schatzberg.dan@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 8e060a6d4945c..9ee5a9a261cc6 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -2066,7 +2066,7 @@ static void enqueue_task_scx(struct rq *rq, struct task_struct *p, int enq_flags
 	rq->scx.nr_running++;
 	add_nr_running(rq, 1);
 
-	if (SCX_HAS_OP(runnable))
+	if (SCX_HAS_OP(runnable) && !task_on_rq_migrating(p))
 		SCX_CALL_OP_TASK(SCX_KF_REST, runnable, p, enq_flags);
 
 	if (enq_flags & SCX_ENQ_WAKEUP)
@@ -2150,7 +2150,7 @@ static bool dequeue_task_scx(struct rq *rq, struct task_struct *p, int deq_flags
 		SCX_CALL_OP_TASK(SCX_KF_REST, stopping, p, false);
 	}
 
-	if (SCX_HAS_OP(quiescent))
+	if (SCX_HAS_OP(quiescent) && !task_on_rq_migrating(p))
 		SCX_CALL_OP_TASK(SCX_KF_REST, quiescent, p, deq_flags);
 
 	if (deq_flags & SCX_DEQ_SLEEP)