diff --git a/sys/vm/vm_object.h b/sys/vm/vm_object.h
--- a/sys/vm/vm_object.h
+++ b/sys/vm/vm_object.h
@@ -197,8 +197,9 @@
 #define	OBJ_SPLIT	0x00000400	/* object is being split */
 #define	OBJ_COLLAPSING	0x00000800	/* Parent of collapse. */
 #define	OBJ_COLORED	0x00001000	/* pg_color is defined */
-#define	OBJ_ONEMAPPING	0x00002000	/* One USE (a single, non-forked)
-					   mapping flag */
+#define	OBJ_ONEMAPPING	0x00002000	/* Each page is allowed to have at most
+					   one managed mapping, all in the same
+					   vm_map */
 #define	OBJ_PAGERPRIV1	0x00004000	/* Pager private */
 #define	OBJ_PAGERPRIV2	0x00008000	/* Pager private */
 #define	OBJ_SYSVSHM	0x00010000	/* SysV SHM */