[deliverable/linux.git] / include / linux / page-flags.h

/*
 * Macros for manipulating and testing page->flags
 */

#ifndef PAGE_FLAGS_H
#define PAGE_FLAGS_H

#include <linux/types.h>

/*
 * Various page->flags bits:
 *
 * PG_reserved is set for special pages, which can never be swapped out. Some
 * of them might not even exist (eg empty_bad_page)...
 *
 * The PG_private bitflag is set if page->private contains a valid value.
 *
 * During disk I/O, PG_locked is used. This bit is set before I/O and
 * reset when I/O completes. page_waitqueue(page) is a wait queue of all tasks
 * waiting for the I/O on this page to complete.
 *
 * PG_uptodate tells whether the page's contents is valid.  When a read
 * completes, the page becomes uptodate, unless a disk I/O error happened.
 *
 * For choosing which pages to swap out, inode pages carry a PG_referenced bit,
 * which is set any time the system accesses that page through the (mapping,
 * index) hash table.  This referenced bit, together with the referenced bit
 * in the page tables, is used to manipulate page->age and move the page across
 * the active, inactive_dirty and inactive_clean lists.
 *
 * Note that the referenced bit, the page->lru list_head and the active,
 * inactive_dirty and inactive_clean lists are protected by the
 * zone->lru_lock, and *NOT* by the usual PG_locked bit!
 *
 * PG_error is set to indicate that an I/O error occurred on this page.
 *
 * PG_arch_1 is an architecture specific page state bit.  The generic code
 * guarantees that this bit is cleared for a page when it first is entered into
 * the page cache.
 *
 * PG_highmem pages are not permanently mapped into the kernel virtual address
 * space, they need to be kmapped separately for doing IO on the pages.  The
 * struct page (these bits with information) are always mapped into kernel
 * address space...
 */

/*
 * Don't use the *_dontuse flags.  Use the macros.  Otherwise you'll break
 * locked- and dirty-page accounting.
 *
 * The page flags field is split into two parts, the main flags area
 * which extends from the low bits upwards, and the fields area which
 * extends from the high bits downwards.
 *
 *  | FIELD | ... | FLAGS |
 *  N-1     ^             0
 *          (N-FLAGS_RESERVED)
 *
 * The fields area is reserved for fields mapping zone, node and SPARSEMEM
 * section.  The boundry between these two areas is defined by
 * FLAGS_RESERVED which defines the width of the fields section
 * (see linux/mmzone.h).  New flags must _not_ overlap with this area.
 */
#define PG_locked	 	 0	/* Page is locked. Don't touch. */
#define PG_error		 1
#define PG_referenced		 2
#define PG_uptodate		 3

#define PG_dirty	 	 4
#define PG_lru			 5
#define PG_active		 6
#define PG_slab			 7	/* slab debug (Suparna wants this) */

#define PG_checked		 8	/* kill me in 2.5.<early>. */
#define PG_arch_1		 9
#define PG_reserved		10
#define PG_private		11	/* Has something at ->private */

#define PG_writeback		12	/* Page is under writeback */
#define PG_nosave		13	/* Used for system suspend/resume */
#define PG_compound		14	/* Part of a compound page */
#define PG_swapcache		15	/* Swap page: swp_entry_t in private */

#define PG_mappedtodisk		16	/* Has blocks allocated on-disk */
#define PG_reclaim		17	/* To be reclaimed asap */
#define PG_nosave_free		18	/* Free, should not be written */
#define PG_buddy		19	/* Page is free, on buddy lists */


#if (BITS_PER_LONG > 32)
/*
 * 64-bit-only flags build down from bit 31
 *
 * 32 bit  -------------------------------| FIELDS |       FLAGS         |
 * 64 bit  |           FIELDS             | ??????         FLAGS         |
 *         63                            32                              0
 */
#define PG_uncached		31	/* Page has been mapped as uncached */
#endif

/*
 * Manipulation of page state flags
 */
#define PageLocked(page)		\
		test_bit(PG_locked, &(page)->flags)
#define SetPageLocked(page)		\
		set_bit(PG_locked, &(page)->flags)
#define TestSetPageLocked(page)		\
		test_and_set_bit(PG_locked, &(page)->flags)
#define ClearPageLocked(page)		\
		clear_bit(PG_locked, &(page)->flags)
#define TestClearPageLocked(page)	\
		test_and_clear_bit(PG_locked, &(page)->flags)

#define PageError(page)		test_bit(PG_error, &(page)->flags)
#define SetPageError(page)	set_bit(PG_error, &(page)->flags)
#define ClearPageError(page)	clear_bit(PG_error, &(page)->flags)

#define PageReferenced(page)	test_bit(PG_referenced, &(page)->flags)
#define SetPageReferenced(page)	set_bit(PG_referenced, &(page)->flags)
#define ClearPageReferenced(page)	clear_bit(PG_referenced, &(page)->flags)
#define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags)

#define PageUptodate(page)	test_bit(PG_uptodate, &(page)->flags)
#ifdef CONFIG_S390
#define SetPageUptodate(_page) \
	do {								      \
		struct page *__page = (_page);				      \
		if (!test_and_set_bit(PG_uptodate, &__page->flags))	      \
			page_test_and_clear_dirty(_page);		      \
	} while (0)
#else
#define SetPageUptodate(page)	set_bit(PG_uptodate, &(page)->flags)
#endif
#define ClearPageUptodate(page)	clear_bit(PG_uptodate, &(page)->flags)

#define PageDirty(page)		test_bit(PG_dirty, &(page)->flags)
#define SetPageDirty(page)	set_bit(PG_dirty, &(page)->flags)
#define TestSetPageDirty(page)	test_and_set_bit(PG_dirty, &(page)->flags)
#define ClearPageDirty(page)	clear_bit(PG_dirty, &(page)->flags)
#define __ClearPageDirty(page)	__clear_bit(PG_dirty, &(page)->flags)
#define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags)

#define PageLRU(page)		test_bit(PG_lru, &(page)->flags)
#define SetPageLRU(page)	set_bit(PG_lru, &(page)->flags)
#define ClearPageLRU(page)	clear_bit(PG_lru, &(page)->flags)
#define __ClearPageLRU(page)	__clear_bit(PG_lru, &(page)->flags)

#define PageActive(page)	test_bit(PG_active, &(page)->flags)
#define SetPageActive(page)	set_bit(PG_active, &(page)->flags)
#define ClearPageActive(page)	clear_bit(PG_active, &(page)->flags)
#define __ClearPageActive(page)	__clear_bit(PG_active, &(page)->flags)

#define PageSlab(page)		test_bit(PG_slab, &(page)->flags)
#define __SetPageSlab(page)	__set_bit(PG_slab, &(page)->flags)
#define __ClearPageSlab(page)	__clear_bit(PG_slab, &(page)->flags)

#ifdef CONFIG_HIGHMEM
#define PageHighMem(page)	is_highmem(page_zone(page))
#else
#define PageHighMem(page)	0 /* needed to optimize away at compile time */
#endif

#define PageChecked(page)	test_bit(PG_checked, &(page)->flags)
#define SetPageChecked(page)	set_bit(PG_checked, &(page)->flags)
#define ClearPageChecked(page)	clear_bit(PG_checked, &(page)->flags)

#define PageReserved(page)	test_bit(PG_reserved, &(page)->flags)
#define SetPageReserved(page)	set_bit(PG_reserved, &(page)->flags)
#define ClearPageReserved(page)	clear_bit(PG_reserved, &(page)->flags)
#define __ClearPageReserved(page)	__clear_bit(PG_reserved, &(page)->flags)

#define SetPagePrivate(page)	set_bit(PG_private, &(page)->flags)
#define ClearPagePrivate(page)	clear_bit(PG_private, &(page)->flags)
#define PagePrivate(page)	test_bit(PG_private, &(page)->flags)
#define __SetPagePrivate(page)  __set_bit(PG_private, &(page)->flags)
#define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags)

#define PageWriteback(page)	test_bit(PG_writeback, &(page)->flags)
#define SetPageWriteback(page)						\
	do {								\
		if (!test_and_set_bit(PG_writeback,			\
				&(page)->flags))			\
			inc_zone_page_state(page, NR_WRITEBACK);	\
	} while (0)
#define TestSetPageWriteback(page)					\
	({								\
		int ret;						\
		ret = test_and_set_bit(PG_writeback,			\
					&(page)->flags);		\
		if (!ret)						\
			inc_zone_page_state(page, NR_WRITEBACK);	\
		ret;							\
	})
#define ClearPageWriteback(page)					\
	do {								\
		if (test_and_clear_bit(PG_writeback,			\
				&(page)->flags))			\
			dec_zone_page_state(page, NR_WRITEBACK);	\
	} while (0)
#define TestClearPageWriteback(page)					\
	({								\
		int ret;						\
		ret = test_and_clear_bit(PG_writeback,			\
				&(page)->flags);			\
		if (ret)						\
			dec_zone_page_state(page, NR_WRITEBACK);	\
		ret;							\
	})

#define PageNosave(page)	test_bit(PG_nosave, &(page)->flags)
#define SetPageNosave(page)	set_bit(PG_nosave, &(page)->flags)
#define TestSetPageNosave(page)	test_and_set_bit(PG_nosave, &(page)->flags)
#define ClearPageNosave(page)		clear_bit(PG_nosave, &(page)->flags)
#define TestClearPageNosave(page)	test_and_clear_bit(PG_nosave, &(page)->flags)

#define PageNosaveFree(page)	test_bit(PG_nosave_free, &(page)->flags)
#define SetPageNosaveFree(page)	set_bit(PG_nosave_free, &(page)->flags)
#define ClearPageNosaveFree(page)		clear_bit(PG_nosave_free, &(page)->flags)

#define PageBuddy(page)		test_bit(PG_buddy, &(page)->flags)
#define __SetPageBuddy(page)	__set_bit(PG_buddy, &(page)->flags)
#define __ClearPageBuddy(page)	__clear_bit(PG_buddy, &(page)->flags)

#define PageMappedToDisk(page)	test_bit(PG_mappedtodisk, &(page)->flags)
#define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags)
#define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags)

#define PageReclaim(page)	test_bit(PG_reclaim, &(page)->flags)
#define SetPageReclaim(page)	set_bit(PG_reclaim, &(page)->flags)
#define ClearPageReclaim(page)	clear_bit(PG_reclaim, &(page)->flags)
#define TestClearPageReclaim(page) test_and_clear_bit(PG_reclaim, &(page)->flags)

#define PageCompound(page)	test_bit(PG_compound, &(page)->flags)
#define __SetPageCompound(page)	__set_bit(PG_compound, &(page)->flags)
#define __ClearPageCompound(page) __clear_bit(PG_compound, &(page)->flags)

#ifdef CONFIG_SWAP
#define PageSwapCache(page)	test_bit(PG_swapcache, &(page)->flags)
#define SetPageSwapCache(page)	set_bit(PG_swapcache, &(page)->flags)
#define ClearPageSwapCache(page) clear_bit(PG_swapcache, &(page)->flags)
#else
#define PageSwapCache(page)	0
#endif

#define PageUncached(page)	test_bit(PG_uncached, &(page)->flags)
#define SetPageUncached(page)	set_bit(PG_uncached, &(page)->flags)
#define ClearPageUncached(page)	clear_bit(PG_uncached, &(page)->flags)

struct page;	/* forward declaration */

int test_clear_page_dirty(struct page *page);
int test_clear_page_writeback(struct page *page);
int test_set_page_writeback(struct page *page);

static inline void clear_page_dirty(struct page *page)
{
	test_clear_page_dirty(page);
}

static inline void set_page_writeback(struct page *page)
{
	test_set_page_writeback(page);
}

#endif	/* PAGE_FLAGS_H */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Macros for manipulating and testing page->flags
	3	*/
	4
	5	#ifndef PAGE_FLAGS_H
	6	#define PAGE_FLAGS_H
	7
f886ed44 AM	8	#include <linux/types.h>
f886ed44 AM	9
1da177e4 LT	10	/*
	11	* Various page->flags bits:
	12	*
	13	* PG_reserved is set for special pages, which can never be swapped out. Some
	14	* of them might not even exist (eg empty_bad_page)...
	15	*
	16	* The PG_private bitflag is set if page->private contains a valid value.
	17	*
	18	* During disk I/O, PG_locked is used. This bit is set before I/O and
	19	* reset when I/O completes. page_waitqueue(page) is a wait queue of all tasks
	20	* waiting for the I/O on this page to complete.
	21	*
	22	* PG_uptodate tells whether the page's contents is valid. When a read
	23	* completes, the page becomes uptodate, unless a disk I/O error happened.
	24	*
	25	* For choosing which pages to swap out, inode pages carry a PG_referenced bit,
	26	* which is set any time the system accesses that page through the (mapping,
	27	* index) hash table. This referenced bit, together with the referenced bit
	28	* in the page tables, is used to manipulate page->age and move the page across
	29	* the active, inactive_dirty and inactive_clean lists.
	30	*
	31	* Note that the referenced bit, the page->lru list_head and the active,
	32	* inactive_dirty and inactive_clean lists are protected by the
	33	* zone->lru_lock, and NOT by the usual PG_locked bit!
	34	*
	35	* PG_error is set to indicate that an I/O error occurred on this page.
	36	*
	37	* PG_arch_1 is an architecture specific page state bit. The generic code
	38	* guarantees that this bit is cleared for a page when it first is entered into
	39	* the page cache.
	40	*
	41	* PG_highmem pages are not permanently mapped into the kernel virtual address
	42	* space, they need to be kmapped separately for doing IO on the pages. The
	43	* struct page (these bits with information) are always mapped into kernel
	44	* address space...
	45	*/
	46
	47	/*
	48	* Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
91fc8ab3 AW	49	* locked- and dirty-page accounting.
	50	*
	51	* The page flags field is split into two parts, the main flags area
	52	* which extends from the low bits upwards, and the fields area which
	53	* extends from the high bits downwards.
	54	*
	55	* \| FIELD \| ... \| FLAGS \|
	56	* N-1 ^ 0
	57	* (N-FLAGS_RESERVED)
	58	*
	59	* The fields area is reserved for fields mapping zone, node and SPARSEMEM
	60	* section. The boundry between these two areas is defined by
	61	* FLAGS_RESERVED which defines the width of the fields section
	62	* (see linux/mmzone.h). New flags must _not_ overlap with this area.
1da177e4 LT	63	*/
	64	#define PG_locked 0 /* Page is locked. Don't touch. */
	65	#define PG_error 1
	66	#define PG_referenced 2
	67	#define PG_uptodate 3
	68
	69	#define PG_dirty 4
	70	#define PG_lru 5
	71	#define PG_active 6
	72	#define PG_slab 7 /* slab debug (Suparna wants this) */
	73
cbe37d09 BP	74	#define PG_checked 8 /* kill me in 2.5.<early>. */
	75	#define PG_arch_1 9
	76	#define PG_reserved 10
	77	#define PG_private 11 /* Has something at ->private */
	78
	79	#define PG_writeback 12 /* Page is under writeback */
	80	#define PG_nosave 13 /* Used for system suspend/resume */
	81	#define PG_compound 14 /* Part of a compound page */
	82	#define PG_swapcache 15 /* Swap page: swp_entry_t in private */
	83
	84	#define PG_mappedtodisk 16 /* Has blocks allocated on-disk */
	85	#define PG_reclaim 17 /* To be reclaimed asap */
	86	#define PG_nosave_free 18 /* Free, should not be written */
676165a8 NP	87	#define PG_buddy 19 /* Page is free, on buddy lists */
676165a8 NP	88
f886ed44 AM	89
	90	#if (BITS_PER_LONG > 32)
	91	/*
	92	* 64-bit-only flags build down from bit 31
	93	*
	94	* 32 bit -------------------------------\| FIELDS \| FLAGS \|
	95	* 64 bit \| FIELDS \| ?????? FLAGS \|
	96	* 63 32 0
	97	*/
	98	#define PG_uncached 31 /* Page has been mapped as uncached */
	99	#endif
1da177e4	100
1da177e4 LT	101	/*
	102	* Manipulation of page state flags
	103	*/
	104	#define PageLocked(page) \
	105	test_bit(PG_locked, &(page)->flags)
	106	#define SetPageLocked(page) \
	107	set_bit(PG_locked, &(page)->flags)
	108	#define TestSetPageLocked(page) \
	109	test_and_set_bit(PG_locked, &(page)->flags)
	110	#define ClearPageLocked(page) \
	111	clear_bit(PG_locked, &(page)->flags)
	112	#define TestClearPageLocked(page) \
	113	test_and_clear_bit(PG_locked, &(page)->flags)
	114
	115	#define PageError(page) test_bit(PG_error, &(page)->flags)
	116	#define SetPageError(page) set_bit(PG_error, &(page)->flags)
	117	#define ClearPageError(page) clear_bit(PG_error, &(page)->flags)
	118
	119	#define PageReferenced(page) test_bit(PG_referenced, &(page)->flags)
	120	#define SetPageReferenced(page) set_bit(PG_referenced, &(page)->flags)
	121	#define ClearPageReferenced(page) clear_bit(PG_referenced, &(page)->flags)
	122	#define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags)
	123
	124	#define PageUptodate(page) test_bit(PG_uptodate, &(page)->flags)
f6ac2354 CL	125	#ifdef CONFIG_S390
	126	#define SetPageUptodate(_page) \
	127	do { \
	128	struct page *__page = (_page); \
	129	if (!test_and_set_bit(PG_uptodate, &__page->flags)) \
	130	page_test_and_clear_dirty(_page); \
	131	} while (0)
	132	#else
1da177e4 LT	133	#define SetPageUptodate(page) set_bit(PG_uptodate, &(page)->flags)
	134	#endif
	135	#define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags)
	136
	137	#define PageDirty(page) test_bit(PG_dirty, &(page)->flags)
	138	#define SetPageDirty(page) set_bit(PG_dirty, &(page)->flags)
	139	#define TestSetPageDirty(page) test_and_set_bit(PG_dirty, &(page)->flags)
	140	#define ClearPageDirty(page) clear_bit(PG_dirty, &(page)->flags)
242e5468	141	#define __ClearPageDirty(page) __clear_bit(PG_dirty, &(page)->flags)
1da177e4 LT	142	#define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags)
1da177e4 LT	143
1da177e4	144	#define PageLRU(page) test_bit(PG_lru, &(page)->flags)
8d438f96 NP	145	#define SetPageLRU(page) set_bit(PG_lru, &(page)->flags)
8d438f96 NP	146	#define ClearPageLRU(page) clear_bit(PG_lru, &(page)->flags)
67453911	147	#define __ClearPageLRU(page) __clear_bit(PG_lru, &(page)->flags)
1da177e4 LT	148
	149	#define PageActive(page) test_bit(PG_active, &(page)->flags)
	150	#define SetPageActive(page) set_bit(PG_active, &(page)->flags)
	151	#define ClearPageActive(page) clear_bit(PG_active, &(page)->flags)
67453911	152	#define __ClearPageActive(page) __clear_bit(PG_active, &(page)->flags)
1da177e4 LT	153
1da177e4 LT	154	#define PageSlab(page) test_bit(PG_slab, &(page)->flags)
f205b2fe NP	155	#define __SetPageSlab(page) __set_bit(PG_slab, &(page)->flags)
f205b2fe NP	156	#define __ClearPageSlab(page) __clear_bit(PG_slab, &(page)->flags)
1da177e4 LT	157
1da177e4 LT	158	#ifdef CONFIG_HIGHMEM
cbe37d09	159	#define PageHighMem(page) is_highmem(page_zone(page))
1da177e4 LT	160	#else
	161	#define PageHighMem(page) 0 /* needed to optimize away at compile time */
	162	#endif
	163
	164	#define PageChecked(page) test_bit(PG_checked, &(page)->flags)
	165	#define SetPageChecked(page) set_bit(PG_checked, &(page)->flags)
	166	#define ClearPageChecked(page) clear_bit(PG_checked, &(page)->flags)
	167
	168	#define PageReserved(page) test_bit(PG_reserved, &(page)->flags)
	169	#define SetPageReserved(page) set_bit(PG_reserved, &(page)->flags)
	170	#define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags)
	171	#define __ClearPageReserved(page) __clear_bit(PG_reserved, &(page)->flags)
	172
	173	#define SetPagePrivate(page) set_bit(PG_private, &(page)->flags)
	174	#define ClearPagePrivate(page) clear_bit(PG_private, &(page)->flags)
	175	#define PagePrivate(page) test_bit(PG_private, &(page)->flags)
	176	#define __SetPagePrivate(page) __set_bit(PG_private, &(page)->flags)
	177	#define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags)
	178
	179	#define PageWriteback(page) test_bit(PG_writeback, &(page)->flags)
	180	#define SetPageWriteback(page) \
	181	do { \
	182	if (!test_and_set_bit(PG_writeback, \
	183	&(page)->flags)) \
ce866b34	184	inc_zone_page_state(page, NR_WRITEBACK); \
1da177e4 LT	185	} while (0)
	186	#define TestSetPageWriteback(page) \
	187	({ \
	188	int ret; \
	189	ret = test_and_set_bit(PG_writeback, \
	190	&(page)->flags); \
	191	if (!ret) \
ce866b34	192	inc_zone_page_state(page, NR_WRITEBACK); \
1da177e4 LT	193	ret; \
	194	})
	195	#define ClearPageWriteback(page) \
	196	do { \
	197	if (test_and_clear_bit(PG_writeback, \
	198	&(page)->flags)) \
ce866b34	199	dec_zone_page_state(page, NR_WRITEBACK); \
1da177e4 LT	200	} while (0)
	201	#define TestClearPageWriteback(page) \
	202	({ \
	203	int ret; \
	204	ret = test_and_clear_bit(PG_writeback, \
	205	&(page)->flags); \
	206	if (ret) \
ce866b34	207	dec_zone_page_state(page, NR_WRITEBACK); \
1da177e4 LT	208	ret; \
	209	})
	210
	211	#define PageNosave(page) test_bit(PG_nosave, &(page)->flags)
	212	#define SetPageNosave(page) set_bit(PG_nosave, &(page)->flags)
	213	#define TestSetPageNosave(page) test_and_set_bit(PG_nosave, &(page)->flags)
	214	#define ClearPageNosave(page) clear_bit(PG_nosave, &(page)->flags)
	215	#define TestClearPageNosave(page) test_and_clear_bit(PG_nosave, &(page)->flags)
	216
	217	#define PageNosaveFree(page) test_bit(PG_nosave_free, &(page)->flags)
	218	#define SetPageNosaveFree(page) set_bit(PG_nosave_free, &(page)->flags)
	219	#define ClearPageNosaveFree(page) clear_bit(PG_nosave_free, &(page)->flags)
	220
676165a8 NP	221	#define PageBuddy(page) test_bit(PG_buddy, &(page)->flags)
	222	#define __SetPageBuddy(page) __set_bit(PG_buddy, &(page)->flags)
	223	#define __ClearPageBuddy(page) __clear_bit(PG_buddy, &(page)->flags)
	224
1da177e4 LT	225	#define PageMappedToDisk(page) test_bit(PG_mappedtodisk, &(page)->flags)
	226	#define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags)
	227	#define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags)
	228
	229	#define PageReclaim(page) test_bit(PG_reclaim, &(page)->flags)
	230	#define SetPageReclaim(page) set_bit(PG_reclaim, &(page)->flags)
	231	#define ClearPageReclaim(page) clear_bit(PG_reclaim, &(page)->flags)
	232	#define TestClearPageReclaim(page) test_and_clear_bit(PG_reclaim, &(page)->flags)
	233
1da177e4	234	#define PageCompound(page) test_bit(PG_compound, &(page)->flags)
5e9dace8 NP	235	#define __SetPageCompound(page) __set_bit(PG_compound, &(page)->flags)
5e9dace8 NP	236	#define __ClearPageCompound(page) __clear_bit(PG_compound, &(page)->flags)
1da177e4 LT	237
	238	#ifdef CONFIG_SWAP
	239	#define PageSwapCache(page) test_bit(PG_swapcache, &(page)->flags)
	240	#define SetPageSwapCache(page) set_bit(PG_swapcache, &(page)->flags)
	241	#define ClearPageSwapCache(page) clear_bit(PG_swapcache, &(page)->flags)
	242	#else
	243	#define PageSwapCache(page) 0
	244	#endif
	245
	246	#define PageUncached(page) test_bit(PG_uncached, &(page)->flags)
	247	#define SetPageUncached(page) set_bit(PG_uncached, &(page)->flags)
	248	#define ClearPageUncached(page) clear_bit(PG_uncached, &(page)->flags)
	249
	250	struct page; /* forward declaration */
	251
	252	int test_clear_page_dirty(struct page *page);
	253	int test_clear_page_writeback(struct page *page);
	254	int test_set_page_writeback(struct page *page);
	255
	256	static inline void clear_page_dirty(struct page *page)
	257	{
	258	test_clear_page_dirty(page);
	259	}
	260
	261	static inline void set_page_writeback(struct page *page)
	262	{
	263	test_set_page_writeback(page);
	264	}
	265
	266	#endif /* PAGE_FLAGS_H */