[PATCH 1/2] sched/fair: Decrease cfs bandwidth usage in task_group destruction

[Chuyi Zhou]

The static key __cfs_bandwidth_used is used to indicate whether bandwidth
control is enabled in the system. Currently, it is only decreased when a
task group disables bandwidth control. This is incorrect because if there
was a task group in the past that enabled bandwidth control, the
__cfs_bandwidth_used will never go to zero, even if there are no task_group
using bandwidth control now.

This patch tries to fix this issue by decrsasing bandwidth usage in
destroy_cfs_bandwidth().

Signed-off-by: Chuyi Zhou <zhouchuyi@xxxxxxxxxxxxx>
---
 kernel/sched/fair.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index b1e07ce90284..7ad50dc31a93 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6447,6 +6447,9 @@ static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
 	hrtimer_cancel(&cfs_b->period_timer);
 	hrtimer_cancel(&cfs_b->slack_timer);
 
+	if (cfs_b->quota != RUNTIME_INF)
+		cfs_bandwidth_usage_dec();
+
 	/*
 	 * It is possible that we still have some cfs_rq's pending on a CSD
 	 * list, though this race is very rare. In order for this to occur, we
-- 
2.20.1