diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-05-05 17:50:21 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-05-05 20:07:57 +0200 |
| commit | 60aa605dfce2976e54fa76e805ab0f221372d4d9 (patch) | |
| tree | 097a6ddd4127039f79e36a2e9100b653551d997d /kernel | |
| parent | 6e29ec5701e9d44fa02b96c1c5c45f7516182b65 (diff) | |
sched: rt: document the risk of small values in the bandwidth settings
Thomas noted that we should disallow sysctl_sched_rt_runtime == 0 for
(!RT_GROUP) since the root group always has some RT tasks in it.
Further, update the documentation to inspire clue.
[ Impact: exclude corner-case sysctl_sched_rt_runtime value ]
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090505155436.863098054@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 54d67b94f1a..2a43a581ead 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -9917,6 +9917,13 @@ static int sched_rt_global_constraints(void) if (sysctl_sched_rt_period <= 0) return -EINVAL; + /* + * There's always some RT tasks in the root group + * -- migration, kstopmachine etc.. + */ + if (sysctl_sched_rt_runtime == 0) + return -EBUSY; + spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); for_each_possible_cpu(i) { struct rt_rq *rt_rq = &cpu_rq(i)->rt; |