path: root/kernel/rcupdate.c
diff options
authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2009-08-15 09:53:48 -0700
committerIngo Molnar <mingo@elte.hu>2009-08-15 19:02:08 +0200
commit2e597558086dec36d5c33521a36e0f6b1bc3f3a7 (patch)
treece8c6ced1c8a3b6bf6170a5894e1d7102e6ee9d4 /kernel/rcupdate.c
parent799e64f05f4bfaad2bb3165cab95c8c992a1c296 (diff)
rcu: Simplify RCU CPU-hotplug notification
Use the new cpu_notifier() API to simplify RCU's CPU-hotplug notifiers, collapsing down to a single such notifier. This makes it trivial to provide the notifier-ordering guarantee that rcu_barrier() depends on. Also remove redundant open_softirq() calls from Hierarchical RCU notifier. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: josht@linux.vnet.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: hugh.dickins@tiscali.co.uk Cc: benh@kernel.crashing.org LKML-Reference: <12503552312510-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/rcupdate.c')
1 files changed, 15 insertions, 1 deletions
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index eae29c25fb1..8df115600c2 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -217,9 +217,13 @@ static void rcu_migrate_callback(struct rcu_head *notused)
+extern int rcu_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu);
static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self,
unsigned long action, void *hcpu)
+ rcu_cpu_notify(self, action, hcpu);
if (action == CPU_DYING) {
* preempt_disable() in on_each_cpu() prevents stop_machine(),
@@ -244,8 +248,18 @@ static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self,
void __init rcu_init(void)
+ int i;
- hotcpu_notifier(rcu_barrier_cpu_hotplug, 0);
+ cpu_notifier(rcu_barrier_cpu_hotplug, 0);
+ /*
+ * We don't need protection against CPU-hotplug here because
+ * this is called early in boot, before either interrupts
+ * or the scheduler are operational.
+ */
+ for_each_online_cpu(i)
+ rcu_barrier_cpu_hotplug(NULL, CPU_UP_PREPARE, (void *)(long)i);
void rcu_scheduler_starting(void)