sched: rt-group: refure unrunnable tasks
Refuse to accept or create RT tasks in groups that can't run them.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched.c b/kernel/sched.c
index d2f4398..f28f19e6 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4584,6 +4584,15 @@
return -EPERM;
}
+#ifdef CONFIG_RT_GROUP_SCHED
+ /*
+ * Do not allow realtime tasks into groups that have no runtime
+ * assigned.
+ */
+ if (rt_policy(policy) && task_group(p)->rt_runtime == 0)
+ return -EPERM;
+#endif
+
retval = security_task_setscheduler(p, policy, param);
if (retval)
return retval;
@@ -8028,9 +8037,15 @@
cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct task_struct *tsk)
{
+#ifdef CONFIG_RT_GROUP_SCHED
+ /* Don't accept realtime tasks when there is no way for them to run */
+ if (rt_task(tsk) && cgroup_tg(cgrp)->rt_runtime == 0)
+ return -EINVAL;
+#else
/* We don't support RT-tasks being in separate groups */
if (tsk->sched_class != &fair_sched_class)
return -EINVAL;
+#endif
return 0;
}