From: Shawn Bohrer Date: Mon, 14 Jan 2013 17:55:31 +0000 (-0600) Subject: sched/rt: Use root_domain of rt_rq not current processor X-Git-Tag: v3.2.39~61 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=7fc80853e471b5442bd0e793f4eadf102cdd5faa;p=karo-tx-linux.git sched/rt: Use root_domain of rt_rq not current processor 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 Acked-by: Steven Rostedt Acked-by: Mike Galbraith Cc: peterz@infradead.org Link: http://lkml.kernel.org/r/1358186131-29494-1-git-send-email-sbohrer@rgmadvisors.com Signed-off-by: Ingo Molnar [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings --- diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 78fcacf8715e..6ad4fb394b08 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -384,7 +384,7 @@ static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq) 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;