This is a note to let you know that I've just added the patch titled
sched/rt: Use root_domain of rt_rq not current processor
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sched-rt-use-root_domain-of-rt_rq-not-current-processor.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From aa7f67304d1a03180f463258aa6f15a8b434e77d Mon Sep 17 00:00:00 2001
From: Shawn Bohrer <[email protected]>
Date: Mon, 14 Jan 2013 11:55:31 -0600
Subject: sched/rt: Use root_domain of rt_rq not current processor
From: Shawn Bohrer <[email protected]>
commit aa7f67304d1a03180f463258aa6f15a8b434e77d upstream.
When the system has multiple domains do_sched_rt_period_timer()
can run on any CPU and may iterate over all rt_rq in
cpu_online_mask. This means when balance_runtime() is run for a
given rt_rq that rt_rq may be in a different rd than the current
processor. Thus if we use smp_processor_id() to get rd in
do_balance_runtime() we may borrow runtime from a rt_rq that is
not part of our rd.
This changes do_balance_runtime to get the rd from the passed in
rt_rq ensuring that we borrow runtime only from the correct rd
for the given rt_rq.
This fixes a BUG at kernel/sched/rt.c:687! in __disable_runtime
when we try reclaim runtime lent to other rt_rq but runtime has
been lent to a rt_rq in another rd.
Signed-off-by: Shawn Bohrer <[email protected]>
Acked-by: Steven Rostedt <[email protected]>
Acked-by: Mike Galbraith <[email protected]>
Cc: [email protected]
Link:
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
kernel/sched/rt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -560,7 +560,7 @@ static inline struct rt_bandwidth *sched
static int do_balance_runtime(struct rt_rq *rt_rq)
{
struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
- struct root_domain *rd = cpu_rq(smp_processor_id())->rd;
+ struct root_domain *rd = rq_of_rt_rq(rt_rq)->rd;
int i, weight, more = 0;
u64 rt_period;
Patches currently in stable-queue which might be from [email protected]
are
queue-3.4/sched-rt-use-root_domain-of-rt_rq-not-current-processor.patch
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