From ad1b99096a48d7cbeb07991f0a4015bbbd82645d Mon Sep 17 00:00:00 2001
From: Lai Jiangshan <laijs@cn.fujitsu.com>
Date: Thu, 29 Sep 2011 13:55:11 -0400
Subject: [PATCH] urcu,call_rcu: avoid create call_rcu_data for child when
 unneed

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
 urcu-call-rcu-impl.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/urcu-call-rcu-impl.h b/urcu-call-rcu-impl.h
index d5b75c0..d964c47 100644
--- a/urcu-call-rcu-impl.h
+++ b/urcu-call-rcu-impl.h
@@ -677,6 +677,10 @@ void call_rcu_after_fork_child(void)
 	/* Release the mutex. */
 	call_rcu_unlock(&call_rcu_mutex);
 
+	/* Do nothing when call_rcu() has not been used */
+	if (cds_list_empty(&call_rcu_data_list))
+		return;
+
 	/*
 	 * Allocate a new default call_rcu_data structure in order
 	 * to get a working call_rcu thread to go with it.
-- 
2.34.1