Commit 013e8963 authored by Christoph Lameter's avatar Christoph Lameter Committed by Pekka Enberg
Browse files

Avoid duplicate _count variables in page_struct 



Restructure the union / struct cascade in struct page so that
we only have one definition of _count.

Tested-by: default avatarHugh Dickins <hughd@google.com>
Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarPekka Enberg <penberg@kernel.org>
parent 3adf004d

include/linux/mm_types.h

+19 −18
Original line number Diff line number Diff line
@@ -49,31 +49,32 @@ struct page { 
					 * see PAGE_MAPPING_ANON below.

					 */

	/* Second double word */

	union {

	struct {

		union {

			pgoff_t index;		/* Our offset within mapping. */

			void *freelist;		/* slub first free object */

		};



		union {

			/* Used for cmpxchg_double in slub */

			unsigned long counters;



			struct {



				union {

					atomic_t _mapcount;	/* Count of ptes mapped in mms,

							 * to show when page is mapped

							 * & limit reverse map searches.

							 */

			atomic_t _count;		/* Usage count, see below. */

		};



		struct {			/* SLUB cmpxchg_double area */

			void *freelist;

			union {

				unsigned long counters;

					struct {

						unsigned inuse:16;

						unsigned objects:15;

						unsigned frozen:1;

					/*

					 * Kernel may make use of this field even when slub

					 * uses the rest of the double word!

					 */

					atomic_t _count;

					};

				};

				atomic_t _count;		/* Usage count, see below. */

			};

		};

	};