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 <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
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LKML-Reference: <12503552312510-git-send-email->
Signed-off-by: Ingo Molnar <[email protected]>
This commit is contained in:
Paul E. McKenney 2009-08-15 09:53:48 -07:00 • committed by Ingo Molnar
commit 2e59755808
3 changed files with 22 additions and 36 deletions

View file

@ -217,9 +217,13 @@ static void rcu_migrate_callback(struct rcu_head *notused)
wake_up(&rcu_migrate_wq);
}
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;
__rcu_init();
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)