--- /usr/src/sys/sys/_mutex.h	2008-05-15 22:10:06.000000000 +0200
+++ src/sys/sys/_mutex.h	2008-05-25 16:22:21.000000000 +0200
@@ -37,6 +37,7 @@
 struct mtx {
 	struct lock_object	lock_object;	/* Common lock properties. */
 	volatile uintptr_t	mtx_lock;	/* Owner and flags. */
-};
+	char pad[24];
+} __aligned(64);
 
 #endif /* !_SYS__MUTEX_H_ */
--- /usr/src/sys/sys/_sx.h	2008-05-15 22:10:06.000000000 +0200
+++ src/sys/sys/_sx.h	2008-05-25 16:23:33.000000000 +0200
@@ -37,6 +37,7 @@
 struct sx {
 	struct lock_object	lock_object;
 	volatile uintptr_t	sx_lock;
-};
+	char pad[24];
+} __aligned(64);
 
 #endif	/* !_SYS__SX_H_ */