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rcu: Simplify RCU CPU-hotplug notification

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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>
This commit is contained in:
Paul E. McKenney
2009-08-15 09:53:48 -07:00
committed by Ingo Molnar
parent 799e64f05f
commit 2e59755808
3 changed files with 22 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
kernel/rcutree.c
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@@ -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);