[patch 02/20] notifier atomic call chain notrace

Mathieu Desnoyers
2010-07-09T23:40:18Z

[-- Attachment #1: notifier-atomic-call-chain-notrace.patch --]
[-- Type: text/plain, Size: 1424 bytes --]

Being able to use the atomic notifier from cpu idle entry to ensure the tracer
flush the last events in the current subbuffer requires the rcu read-side to be
marked "notrace".

Also apply to the the die notifier.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Masami Hiramatsu <mhiramat@redhat.com>
CC: Jason Baron <jbaron@redhat.com>
CC: mingo@elte.hu
---
kernel/notifier.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

Index: linux-2.6-lttng/kernel/notifier.c
===================================================================
--- linux-2.6-lttng.orig/kernel/notifier.c 2009-11-12 17:58:56.000000000 -0500
+++ linux-2.6-lttng/kernel/notifier.c 2009-11-12 18:03:28.000000000 -0500
@@ -148,7 +148,7 @@ int atomic_notifier_chain_unregister(str
spin_lock_irqsave(&nh->lock, flags);
ret = notifier_chain_unregister(&nh->head, n);
spin_unlock_irqrestore(&nh->lock, flags);
- synchronize_rcu();
+ synchronize_sched();
return ret;
}
EXPORT_SYMBOL_GPL(atomic_notifier_chain_unregister);
@@ -178,9 +178,9 @@ int __kprobes __atomic_notifier_call_cha
{
int ret;

- rcu_read_lock();
+ rcu_read_lock_sched_notrace();
ret = notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls);
- rcu_read_unlock();
+ rcu_read_unlock_sched_notrace();
return ret;
}
EXPORT_SYMBOL_GPL(__atomic_notifier_call_chain);