re #13613 rb4516 Tunables needs volatile keyword

@@ -21,10 +21,13 @@
  */
 /*
  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
+/*
+ * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
+ */
 
 /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
 /*        All Rights Reserved   */
 
 

@@ -36,15 +39,15 @@
 #endif
 
 /*
  * pointer to swapfs global data structures
  */
-extern pgcnt_t swapfs_minfree;          /* amount of availrmem (in pages) */
+extern volatile pgcnt_t swapfs_minfree; /* amount of availrmem (in pages) */
                                         /* that is unavailable to swapfs */
 extern pgcnt_t swapfs_desfree;
 
-extern pgcnt_t swapfs_reserve;          /* amount of availrmem (in pages) */
+extern volatile pgcnt_t swapfs_reserve; /* amount of availrmem (in pages) */
                                         /* that is unavailable for swap */
                                         /* reservation to non-priv processes */
 
 extern struct vnodeops *swap_vnodeops;
 extern struct vnode *swapfs_getvp(ulong_t);