+ mm-improve-comment-on-page-mapping.patch added to -mm tree

+ mm-improve-comment-on-page-mapping.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm: improve comment on page->mapping
has been added to the -mm tree.  Its filename is
     mm-improve-comment-on-page-mapping.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/mm-improve-comment-on-page-mapping.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/mm-improve-comment-on-page-mapping.patch

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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Matthew Wilcox <mawilcox@microsoft.com>
Subject: mm: improve comment on page->mapping

The comment on page->mapping is terse, and out of date (it does not
mention the possibility of PAGE_MAPPING_MOVABLE).  Instead, point the
interested reader to page-flags.h where there is a much better comment.

Link: http://lkml.kernel.org/r/20171220155552.15884-5-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/mm_types.h |   12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff -puN include/linux/mm_types.h~mm-improve-comment-on-page-mapping include/linux/mm_types.h
--- a/include/linux/mm_types.h~mm-improve-comment-on-page-mapping
+++ a/include/linux/mm_types.h
@@ -50,15 +50,9 @@ struct page {
 	unsigned long flags;		/* Atomic flags, some possibly
 					 * updated asynchronously */
 	union {
-		struct address_space *mapping;	/* If low bit clear, points to
-						 * inode address_space, or NULL.
-						 * If page mapped as anonymous
-						 * memory, low bit is set, and
-						 * it points to anon_vma object
-						 * or KSM private structure. See
-						 * PAGE_MAPPING_ANON and
-						 * PAGE_MAPPING_KSM.
-						 */
+		/* See page-flags.h for the definition of PAGE_MAPPING_FLAGS */
+		struct address_space *mapping;
+
 		void *s_mem;			/* slab first object */
 		atomic_t compound_mapcount;	/* first tail page */
 		/* page_deferred_list().next	 -- second tail page */
_

Patches currently in -mm which might be from mawilcox@microsoft.com are

provide-useful-debugging-information-for-vm_bug.patch
mm-align-struct-page-more-aesthetically.patch
mm-de-indent-struct-page.patch
mm-remove-misleading-alignment-claims.patch
mm-improve-comment-on-page-mapping.patch
mm-introduce-_slub_counter_t.patch
mm-store-compound_dtor-compound_order-as-bytes.patch
mm-document-how-to-use-struct-page.patch
mm-remove-reference-to-pg_buddy.patch