sched: rt: fix the bandwidth contraint computations

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Daniel K." <dk@uw.no>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 8 insertions, 3 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 5b307da827ef..1f711a58a2b4 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -8419,7 +8419,7 @@ static unsigned long to_ratio(u64 period, u64 runtime)
 #ifdef CONFIG_CGROUP_SCHED
 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
 {
-        struct task_group *tgi, *parent = tg ? tg->parent : NULL;
+        struct task_group *tgi, *parent = tg->parent;
         unsigned long total = 0;
 
         if (!parent) {
@@ -8443,7 +8443,7 @@ static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
         }
         rcu_read_unlock();
 
-        return total + to_ratio(period, runtime) <
+        return total + to_ratio(period, runtime) <=
                 to_ratio(ktime_to_ns(parent->rt_bandwidth.rt_period),
                                 parent->rt_bandwidth.rt_runtime);
 }
@@ -8560,10 +8560,15 @@ long sched_group_rt_period(struct task_group *tg)
 
 static int sched_rt_global_constraints(void)
 {
+        struct task_group *tg = &root_task_group;
+        u64 rt_runtime, rt_period;
         int ret = 0;
 
+        rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
+        rt_runtime = tg->rt_bandwidth.rt_runtime;
+
         mutex_lock(&rt_constraints_mutex);
-        if (!__rt_schedulable(NULL, 1, 0))
+        if (!__rt_schedulable(tg, rt_period, rt_runtime))
                 ret = -EINVAL;
         mutex_unlock(&rt_constraints_mutex);