Cherry-pick from 9-STABLE (SVN rev 233769).

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=666747
http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/155411

--- a/sys/fs/tmpfs/tmpfs.h
+++ b/sys/fs/tmpfs/tmpfs.h
@@ -502,11 +502,8 @@
 static __inline size_t
 tmpfs_mem_info(void)
 {
-	size_t size;
 
-	size = swap_pager_avail + cnt.v_free_count + cnt.v_inactive_count;
-	size -= size > cnt.v_wire_count ? cnt.v_wire_count : size;
-	return size;
+	return (swap_pager_avail + cnt.v_free_count + cnt.v_cache_count);
 }
 
 /* Returns the maximum size allowed for a tmpfs file system.  This macro