commit bbad937983147c017c25406860287cb94da9af7c
author Paul E. McKenney <paulmck@linux.vnet.ibm.com> Fri Apr 02 16:17:17 2010 -0700
committer Paul E. McKenney <paulmck@linux.vnet.ibm.com> Mon May 10 11:08:34 2010 -0700
tree 57311598c360b92b189c7ec337146e4bc779c73d
parent 25502a6c13745f4650cc59322bd198194f55e796

rcu: slim down rcutiny by removing rcu_scheduler_active and friends

TINY_RCU does not need rcu_scheduler_active unless CONFIG_DEBUG_LOCK_ALLOC.
So conditionally compile rcu_scheduler_active in order to slim down
rcutiny a bit more.  Also gets rid of an EXPORT_SYMBOL_GPL, which is
responsible for most of the slimming.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

include/linux/rcupdate.h

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index d8fb2ab..23be3a7 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -64,8 +64,6 @@
 
 /* Internal to kernel */
 extern void rcu_init(void);
-extern int rcu_scheduler_active;
-extern void rcu_scheduler_starting(void);
 
 #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
 #include <linux/rcutree.h>
@@ -178,7 +176,7 @@
 #ifdef CONFIG_PREEMPT
 static inline int rcu_read_lock_sched_held(void)
 {
-	return !rcu_scheduler_active || preempt_count() != 0 || irqs_disabled();
+	return preempt_count() != 0 || irqs_disabled();
 }
 #else /* #ifdef CONFIG_PREEMPT */
 static inline int rcu_read_lock_sched_held(void)

include/linux/rcutiny.h

diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index ff22b97..14e5a76 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -128,4 +128,17 @@
 	return 0;
 }
 
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
+extern int rcu_scheduler_active __read_mostly;
+extern void rcu_scheduler_starting(void);
+
+#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+
+static inline void rcu_scheduler_starting(void)
+{
+}
+
+#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+
 #endif /* __LINUX_RCUTINY_H */

include/linux/rcutree.h

diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index b9f7460..4828205 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -123,4 +123,7 @@
 	return num_online_cpus() == 1;
 }
 
+extern void rcu_scheduler_starting(void);
+extern int rcu_scheduler_active __read_mostly;
+
 #endif /* __LINUX_RCUTREE_H */