[RFC PATCH v7 23/29] sched/core: Execute enqueued balance callbacks after migrate_disable_switch

[Yuri Andriaccio <yurand2000@gmail.com>]

Execute balance callbacks after migrate_disable_switch.
  Balancing may be requested on the __schedule path, in migrate_disable_switch,
  when the running task is throttled and then pushed away from its runqueue.

Signed-off-by: Yuri Andriaccio <yurand2000@gmail.com>
---
 kernel/sched/core.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index aef019cef859..e4e50202896d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2470,6 +2470,9 @@ do_set_cpus_allowed(struct task_struct *p, struct affinity_context *ctx);

 static void migrate_disable_switch(struct rq *rq, struct task_struct *p)
 {
+	struct rq_flags rf;
+	struct balance_callback *head;
+
 	struct affinity_context ac = {
 		.new_mask  = cpumask_of(rq->cpu),
 		.flags     = SCA_MIGRATE_DISABLE,
@@ -2481,8 +2484,13 @@ static void migrate_disable_switch(struct rq *rq, struct task_struct *p)
 	if (p->cpus_ptr != &p->cpus_mask)
 		return;

-	scoped_guard (task_rq_lock, p)
-		do_set_cpus_allowed(p, &ac);
+	rq = task_rq_lock(p, &rf);
+
+	do_set_cpus_allowed(p, &ac);
+
+	head = splice_balance_callbacks(rq);
+	task_rq_unlock(rq, p, &rf);
+	balance_callbacks(rq, head);
 }

 void ___migrate_enable(void)
--
2.56.0