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-rw-r--r--kernel/sched/core.c22
1 files changed, 19 insertions, 3 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 9140a33bcc97..5ddd9610be56 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -10351,7 +10351,7 @@ void sched_release_group(struct task_group *tg)
spin_unlock_irqrestore(&task_group_lock, flags);
}
-static void sched_change_group(struct task_struct *tsk)
+static struct task_group *sched_get_task_group(struct task_struct *tsk)
{
struct task_group *tg;
@@ -10363,7 +10363,13 @@ static void sched_change_group(struct task_struct *tsk)
tg = container_of(task_css_check(tsk, cpu_cgrp_id, true),
struct task_group, css);
tg = autogroup_task_group(tsk, tg);
- tsk->sched_task_group = tg;
+
+ return tg;
+}
+
+static void sched_change_group(struct task_struct *tsk, struct task_group *group)
+{
+ tsk->sched_task_group = group;
#ifdef CONFIG_FAIR_GROUP_SCHED
if (tsk->sched_class->task_change_group)
@@ -10384,10 +10390,19 @@ void sched_move_task(struct task_struct *tsk)
{
int queued, running, queue_flags =
DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
+ struct task_group *group;
struct rq_flags rf;
struct rq *rq;
rq = task_rq_lock(tsk, &rf);
+ /*
+ * Esp. with SCHED_AUTOGROUP enabled it is possible to get superfluous
+ * group changes.
+ */
+ group = sched_get_task_group(tsk);
+ if (group == tsk->sched_task_group)
+ goto unlock;
+
update_rq_clock(rq);
running = task_current(rq, tsk);
@@ -10398,7 +10413,7 @@ void sched_move_task(struct task_struct *tsk)
if (running)
put_prev_task(rq, tsk);
- sched_change_group(tsk);
+ sched_change_group(tsk, group);
if (queued)
enqueue_task(rq, tsk, queue_flags);
@@ -10412,6 +10427,7 @@ void sched_move_task(struct task_struct *tsk)
resched_curr(rq);
}
+unlock:
task_rq_unlock(rq, tsk, &rf);
}