* The rw_lock is now using a mutex to protect its reader/writer counts. This

makes the reader case a lot less expensive, and should relieve the thread
  spinlock contention a bit.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@33643 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/lock.h

@@ -42,6 +42,7 @@ struct rw_lock_waiter;
 
 typedef struct rw_lock {
 	const char*				name;
+	mutex					lock;
 	struct rw_lock_waiter*	waiters;
 	thread_id				holder;
 	int32					reader_count;
@@ -85,7 +86,8 @@ typedef struct rw_lock {
 #	define RECURSIVE_LOCK_INITIALIZER(name)	{ MUTEX_INITIALIZER(name), -1, 0 }
 #endif
 
-#define RW_LOCK_INITIALIZER(name)			{ name, NULL, -1, 0, 0, 0 }
+#define RW_LOCK_INITIALIZER(name)			{ name, MUTEX_INITIALIZER(name), \
+												NULL, -1, 0, 0, 0 }
 
 
 #if KDEBUG