[PATCH] sched: update sched_rt_[period|runtime]_us correctly

[Yong Zhang]

From: Yong Zhang <yong.zhang@xxxxxxxxxxxxx>

The code fails to update tg->rt_bandwidth.[rt_period | rt_runtime]
if we have RT_GROUP_SCHED enabled. And if we lower the value of
sched_rt_runtime_us, we get error as "write error: Invalid argument".

Fix it by calling tg_set_rt_bandwidth() instead when setting
sched_rt_[period|runtime]_us.

Signed-off-by: Yong Zhang <yong.zhang0@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
---
 kernel/sched/core.c |    6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5ac63c9..c77d298 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7035,11 +7035,7 @@ static int sched_rt_global_constraints(void)
 	if (runtime > period && runtime != RUNTIME_INF)
 		return -EINVAL;
 
-	mutex_lock(&rt_constraints_mutex);
-	read_lock(&tasklist_lock);
-	ret = __rt_schedulable(NULL, 0, 0);
-	read_unlock(&tasklist_lock);
-	mutex_unlock(&rt_constraints_mutex);
+	ret = tg_set_rt_bandwidth(&root_task_group, period, runtime);
 
 	return ret;
 }
-- 
1.7.9.5

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