mm: clean up non-standard page->_mapcount users

[linux-2.6-block.git] / include / linux / mm_types.h

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index a50ad735d518c150fd49b4c35c9ba55d22c70e7c..79472b22d23f0866cd251e3e5e47c902522994e0 100644 (file)
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -85,6 +85,11 @@ struct page {
                                /*
                                 * Count of ptes mapped in mms, to show when
                                 * page is mapped & limit reverse map searches.
+                                *
+                                * Extra information about page type may be
+                                * stored here for pages that are never mapped,
+                                * in which case the value MUST BE <= -2.
+                                * See page-flags.h for more details.
                                 */
                                atomic_t _mapcount;