Commit-ID: bfa00b4c4028f39357d16279ff0fddf550241593
Gitweb: http://git.kernel.org/tip/bfa00b4c4028f39357d16279ff0fddf550241593
Author: Paul E. McKenney <paul.mckenney@xxxxxxxxxx>
AuthorDate: Thu, 21 Jun 2012 09:54:10 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Sun, 23 Sep 2012 07:41:53 -0700
rcu: Prevent offline CPUs from executing RCU core code
Earlier versions of RCU invoked the RCU core from the CPU_DYING notifier
in order to note a quiescent state for the outgoing CPU. Because the
CPU is marked "offline" during the execution of the CPU_DYING notifiers,
the RCU core had to tolerate being invoked from an offline CPU. However,
commit b1420f1c (Make rcu_barrier() less disruptive) left only tracing
code in the CPU_DYING notifier, so the RCU core need no longer execute
on offline CPUs. This commit therefore enforces this restriction.
Signed-off-by: Paul E. McKenney <paul.mckenney@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
---
kernel/rcutree.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index f0c0c1b..340a5f5 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1892,6 +1892,8 @@ static void rcu_process_callbacks(struct softirq_action *unused)
{
struct rcu_state *rsp;
+ if (cpu_is_offline(smp_processor_id()))
+ return;
trace_rcu_utilization("Start RCU core");
for_each_rcu_flavor(rsp)
__rcu_process_callbacks(rsp);
--
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