Commit b26435a0 authored Jan 31, 2018 by Matthew Wilcox Committed by Linus Torvalds Jan 31, 2018

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mapping is terse, and out of date (it does not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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 4cf7c8bf

include/linux/mm_types.h

+3 −9

Original line number	Diff line number	Diff line
		@@ -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 */