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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/rcutree.c
parent799e64f05f4bfaad2bb3165cab95c8c992a1c296 (diff)
downloadlwn-2e597558086dec36d5c33521a36e0f6b1bc3f3a7.tar.gz
lwn-2e597558086dec36d5c33521a36e0f6b1bc3f3a7.zip
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/rcutree.c')
-rw-r--r--kernel/rcutree.c17
1 files changed, 5 insertions, 12 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index f3e43274ed53..75762cddbe03 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1132,6 +1132,8 @@ __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp)
{
unsigned long flags;
+ WARN_ON_ONCE(rdp->beenonline == 0);
+
/*
* If an RCU GP has gone long enough, go check for dyntick
* idle CPUs and, if needed, send resched IPIs.
@@ -1416,14 +1418,13 @@ static void __cpuinit rcu_online_cpu(int cpu)
{
rcu_init_percpu_data(cpu, &rcu_state);
rcu_init_percpu_data(cpu, &rcu_bh_state);
- open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
}
/*
* Handle CPU online/offline notifcation events.
*/
-static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
+int __cpuinit rcu_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
{
long cpu = (long)hcpu;
@@ -1532,10 +1533,6 @@ do { \
} \
} while (0)
-static struct notifier_block __cpuinitdata rcu_nb = {
- .notifier_call = rcu_cpu_notify,
-};
-
void __init __rcu_init(void)
{
int i; /* All used by RCU_DATA_PTR_INIT(). */
@@ -1554,11 +1551,7 @@ void __init __rcu_init(void)
RCU_DATA_PTR_INIT(&rcu_bh_state, rcu_bh_data);
for_each_possible_cpu(i)
rcu_boot_init_percpu_data(i, &rcu_bh_state);
-
- for_each_online_cpu(i)
- rcu_cpu_notify(&rcu_nb, CPU_UP_PREPARE, (void *)(long)i);
- /* Register notifier for non-boot CPUs */
- register_cpu_notifier(&rcu_nb);
+ open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
}
module_param(blimit, int, 0);