Add XXX: comment to vm_pager_unswapped().

sys/vm/vm_pager.h

@@ -177,6 +177,11 @@ vm_pager_has_page(
  *      called at splvm() to destroy swap associated with the page.
  * 
  *      This function may not block.
+ *
+ *	XXX: A much better name would be "vm_pager_page_dirtied()"
+ *	XXX: It is not obvious if this could be profitably used by any
+ *	XXX: pagers besides the swap_pager or if it should even be a
+ *	XXX: generic pager_op in the first place.
  */
 static __inline void
 vm_pager_page_unswapped(vm_page_t m)