From 98a4826b99bc4bcc34c604b2fc4fcf4d771600ec Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 14 Jan 2009 10:56:32 +0100 Subject: [PATCH] sched: fix bandwidth validation for UID grouping Impact: make rt-limit tunables work again Mark Glines reported: > I've got an issue on x86-64 where I can't configure the system to allow > RT tasks for a non-root user. > > In 2.6.26.5, I was able to do the following to set things up nicely: > echo 450000 >/sys/kernel/uids/0/cpu_rt_runtime > echo 450000 >/sys/kernel/uids/1000/cpu_rt_runtime > > Seems like every value I try to echo into the /sys files returns EINVAL. For UID grouping we initialize the root group with infinite bandwidth which by default is actually more than the global limit, therefore the bandwidth check always fails. Because the root group is a phantom group (for UID grouping) we cannot runtime adjust it, therefore we let it reflect the global bandwidth settings. Reported-by: Mark Glines Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/sched.c b/kernel/sched.c index 3b630d88266..ed62d1cee05 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -9050,6 +9050,13 @@ static int tg_schedulable(struct task_group *tg, void *data) runtime = d->rt_runtime; } +#ifdef CONFIG_USER_SCHED + if (tg == &root_task_group) { + period = global_rt_period(); + runtime = global_rt_runtime(); + } +#endif + /* * Cannot have more runtime than the period. */ -- 2.41.1