sched: Warn on rt throttling

The default rt-throttling is a source of never ending questions. Warn
once when we go into throttling so folks have that info in dmesg.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1110051331480.18778@ionos
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 3023fd1ef3640d30da6ee8d5928584b8d5fcfdf6..056cbd2e2a27fea8cb15e76bfc711fe32de03303 100644 (file)
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -655,6 +655,7 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
 
        if (rt_rq->rt_time > runtime) {
                rt_rq->rt_throttled = 1;
+               printk_once(KERN_WARNING "sched: RT throttling activated\n");
                if (rt_rq_throttled(rt_rq)) {
                        sched_rt_rq_dequeue(rt_rq);
                        return 1;