[linux-2.6-block.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>
#ifndef __GENERATING_BOUNDS_H
#include <linux/mm_types.h>
#include <linux/bounds.h>
#endif /* !__GENERATING_BOUNDS_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 on pagecache pages if they contain filesystem
 * specific data (which is normally at page->private). It can be used by
 * private allocations for its own usage.
 *
 * During initiation of disk I/O, PG_locked is set. This bit is set before I/O
 * and cleared when writeback _starts_ or when read _completes_. PG_writeback
 * is set before writeback starts and cleared when it finishes.
 *
 * PG_locked also pins a page in pagecache, and blocks truncation of the file
 * while it is held.
 *
 * page_waitqueue(page) is a wait queue of all tasks waiting for the page
 * to become unlocked.
 *
 * 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.
 *
 * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
 * file-backed pagecache (see mm/vmscan.c).
 *
 * 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...
 *
 * PG_buddy is set to indicate that the page is free and in the buddy system
 * (see mm/page_alloc.c).
 *
 */

/*
 * 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
 *               (NR_PAGEFLAGS)
 *
 * The fields area is reserved for fields mapping zone, node (for NUMA) and
 * SPARSEMEM section (for variants of SPARSEMEM that require section ids like
 * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
 */
enum pageflags {
	PG_locked,		/* Page is locked. Don't touch. */
	PG_error,
	PG_referenced,
	PG_uptodate,
	PG_dirty,
	PG_lru,
	PG_active,
	PG_slab,
	PG_owner_priv_1,	/* Owner use. If pagecache, fs may use*/
	PG_arch_1,
	PG_reserved,
	PG_private,		/* If pagecache, has fs-private data */
	PG_writeback,		/* Page is under writeback */
#ifdef CONFIG_PAGEFLAGS_EXTENDED
	PG_head,		/* A head page */
	PG_tail,		/* A tail page */
#else
	PG_compound,		/* A compound page */
#endif
	PG_swapcache,		/* Swap page: swp_entry_t in private */
	PG_mappedtodisk,	/* Has blocks allocated on-disk */
	PG_reclaim,		/* To be reclaimed asap */
	PG_buddy,		/* Page is free, on buddy lists */
	PG_swapbacked,		/* Page is backed by RAM/swap */
#ifdef CONFIG_UNEVICTABLE_LRU
	PG_unevictable,		/* Page is "unevictable"  */
#endif
#ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
	PG_mlocked,		/* Page is vma mlocked */
#endif
#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
	PG_uncached,		/* Page has been mapped as uncached */
#endif
	__NR_PAGEFLAGS,

	/* Filesystems */
	PG_checked = PG_owner_priv_1,

	/* XEN */
	PG_pinned = PG_owner_priv_1,
	PG_savepinned = PG_dirty,

	/* SLOB */
	PG_slob_page = PG_active,
	PG_slob_free = PG_private,

	/* SLUB */
	PG_slub_frozen = PG_active,
	PG_slub_debug = PG_error,
};

#ifndef __GENERATING_BOUNDS_H

/*
 * Macros to create function definitions for page flags
 */
#define TESTPAGEFLAG(uname, lname)					\
static inline int Page##uname(struct page *page) 			\
			{ return test_bit(PG_##lname, &page->flags); }

#define SETPAGEFLAG(uname, lname)					\
static inline void SetPage##uname(struct page *page)			\
			{ set_bit(PG_##lname, &page->flags); }

#define CLEARPAGEFLAG(uname, lname)					\
static inline void ClearPage##uname(struct page *page)			\
			{ clear_bit(PG_##lname, &page->flags); }

#define __SETPAGEFLAG(uname, lname)					\
static inline void __SetPage##uname(struct page *page)			\
			{ __set_bit(PG_##lname, &page->flags); }

#define __CLEARPAGEFLAG(uname, lname)					\
static inline void __ClearPage##uname(struct page *page)		\
			{ __clear_bit(PG_##lname, &page->flags); }

#define TESTSETFLAG(uname, lname)					\
static inline int TestSetPage##uname(struct page *page)			\
		{ return test_and_set_bit(PG_##lname, &page->flags); }

#define TESTCLEARFLAG(uname, lname)					\
static inline int TestClearPage##uname(struct page *page)		\
		{ return test_and_clear_bit(PG_##lname, &page->flags); }


#define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname)		\
	SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname)

#define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname)		\
	__SETPAGEFLAG(uname, lname)  __CLEARPAGEFLAG(uname, lname)

#define PAGEFLAG_FALSE(uname) 						\
static inline int Page##uname(struct page *page) 			\
			{ return 0; }

#define TESTSCFLAG(uname, lname)					\
	TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname)

#define SETPAGEFLAG_NOOP(uname)						\
static inline void SetPage##uname(struct page *page) {  }

#define CLEARPAGEFLAG_NOOP(uname)					\
static inline void ClearPage##uname(struct page *page) {  }

#define __CLEARPAGEFLAG_NOOP(uname)					\
static inline void __ClearPage##uname(struct page *page) {  }

#define TESTCLEARFLAG_FALSE(uname)					\
static inline int TestClearPage##uname(struct page *page) { return 0; }

struct page;	/* forward declaration */

TESTPAGEFLAG(Locked, locked)
PAGEFLAG(Error, error)
PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced)
PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty)
PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru)
PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active)
	TESTCLEARFLAG(Active, active)
__PAGEFLAG(Slab, slab)
PAGEFLAG(Checked, checked)		/* Used by some filesystems */
PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned)	/* Xen */
PAGEFLAG(SavePinned, savepinned);			/* Xen */
PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
PAGEFLAG(Private, private) __CLEARPAGEFLAG(Private, private)
	__SETPAGEFLAG(Private, private)
PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)

__PAGEFLAG(SlobPage, slob_page)
__PAGEFLAG(SlobFree, slob_free)

__PAGEFLAG(SlubFrozen, slub_frozen)
__PAGEFLAG(SlubDebug, slub_debug)

/*
 * Only test-and-set exist for PG_writeback.  The unconditional operators are
 * risky: they bypass page accounting.
 */
TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback)
__PAGEFLAG(Buddy, buddy)
PAGEFLAG(MappedToDisk, mappedtodisk)

/* PG_readahead is only used for file reads; PG_reclaim is only for writes */
PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim)
PAGEFLAG(Readahead, reclaim)		/* Reminder to do async read-ahead */

#ifdef CONFIG_HIGHMEM
/*
 * Must use a macro here due to header dependency issues. page_zone() is not
 * available at this point.
 */
#define PageHighMem(__p) is_highmem(page_zone(__p))
#else
PAGEFLAG_FALSE(HighMem)
#endif

#ifdef CONFIG_SWAP
PAGEFLAG(SwapCache, swapcache)
#else
PAGEFLAG_FALSE(SwapCache)
	SETPAGEFLAG_NOOP(SwapCache) CLEARPAGEFLAG_NOOP(SwapCache)
#endif

#ifdef CONFIG_UNEVICTABLE_LRU
PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable)
	TESTCLEARFLAG(Unevictable, unevictable)
#else
PAGEFLAG_FALSE(Unevictable) TESTCLEARFLAG_FALSE(Unevictable)
	SETPAGEFLAG_NOOP(Unevictable) CLEARPAGEFLAG_NOOP(Unevictable)
	__CLEARPAGEFLAG_NOOP(Unevictable)
#endif

#ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
#define MLOCK_PAGES 1
PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked)
	TESTSCFLAG(Mlocked, mlocked)
#else
#define MLOCK_PAGES 0
PAGEFLAG_FALSE(Mlocked)
	SETPAGEFLAG_NOOP(Mlocked) TESTCLEARFLAG_FALSE(Mlocked)
#endif

#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
PAGEFLAG(Uncached, uncached)
#else
PAGEFLAG_FALSE(Uncached)
#endif

static inline int PageUptodate(struct page *page)
{
	int ret = test_bit(PG_uptodate, &(page)->flags);

	/*
	 * Must ensure that the data we read out of the page is loaded
	 * _after_ we've loaded page->flags to check for PageUptodate.
	 * We can skip the barrier if the page is not uptodate, because
	 * we wouldn't be reading anything from it.
	 *
	 * See SetPageUptodate() for the other side of the story.
	 */
	if (ret)
		smp_rmb();

	return ret;
}

static inline void __SetPageUptodate(struct page *page)
{
	smp_wmb();
	__set_bit(PG_uptodate, &(page)->flags);
}

static inline void SetPageUptodate(struct page *page)
{
#ifdef CONFIG_S390
	if (!test_and_set_bit(PG_uptodate, &page->flags))
		page_clear_dirty(page);
#else
	/*
	 * Memory barrier must be issued before setting the PG_uptodate bit,
	 * so that all previous stores issued in order to bring the page
	 * uptodate are actually visible before PageUptodate becomes true.
	 *
	 * s390 doesn't need an explicit smp_wmb here because the test and
	 * set bit already provides full barriers.
	 */
	smp_wmb();
	set_bit(PG_uptodate, &(page)->flags);
#endif
}

CLEARPAGEFLAG(Uptodate, uptodate)

extern void cancel_dirty_page(struct page *page, unsigned int account_size);

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

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

#ifdef CONFIG_PAGEFLAGS_EXTENDED
/*
 * System with lots of page flags available. This allows separate
 * flags for PageHead() and PageTail() checks of compound pages so that bit
 * tests can be used in performance sensitive paths. PageCompound is
 * generally not used in hot code paths.
 */
__PAGEFLAG(Head, head)
__PAGEFLAG(Tail, tail)

static inline int PageCompound(struct page *page)
{
	return page->flags & ((1L << PG_head) | (1L << PG_tail));

}
#else
/*
 * Reduce page flag use as much as possible by overlapping
 * compound page flags with the flags used for page cache pages. Possible
 * because PageCompound is always set for compound pages and not for
 * pages on the LRU and/or pagecache.
 */
TESTPAGEFLAG(Compound, compound)
__PAGEFLAG(Head, compound)

/*
 * PG_reclaim is used in combination with PG_compound to mark the
 * head and tail of a compound page. This saves one page flag
 * but makes it impossible to use compound pages for the page cache.
 * The PG_reclaim bit would have to be used for reclaim or readahead
 * if compound pages enter the page cache.
 *
 * PG_compound & PG_reclaim	=> Tail page
 * PG_compound & ~PG_reclaim	=> Head page
 */
#define PG_head_tail_mask ((1L << PG_compound) | (1L << PG_reclaim))

static inline int PageTail(struct page *page)
{
	return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask);
}

static inline void __SetPageTail(struct page *page)
{
	page->flags |= PG_head_tail_mask;
}

static inline void __ClearPageTail(struct page *page)
{
	page->flags &= ~PG_head_tail_mask;
}

#endif /* !PAGEFLAGS_EXTENDED */

#ifdef CONFIG_UNEVICTABLE_LRU
#define __PG_UNEVICTABLE	(1 << PG_unevictable)
#else
#define __PG_UNEVICTABLE	0
#endif

#ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
#define __PG_MLOCKED		(1 << PG_mlocked)
#else
#define __PG_MLOCKED		0
#endif

/*
 * Flags checked when a page is freed.  Pages being freed should not have
 * these flags set.  It they are, there is a problem.
 */
#define PAGE_FLAGS_CHECK_AT_FREE \
	(1 << PG_lru   | 1 << PG_private   | 1 << PG_locked | \
	 1 << PG_buddy | 1 << PG_writeback | 1 << PG_reserved | \
	 1 << PG_slab  | 1 << PG_swapcache | 1 << PG_active | \
	 __PG_UNEVICTABLE | __PG_MLOCKED)

/*
 * Flags checked when a page is prepped for return by the page allocator.
 * Pages being prepped should not have any flags set.  It they are set,
 * there has been a kernel bug or struct page corruption.
 */
#define PAGE_FLAGS_CHECK_AT_PREP	((1 << NR_PAGEFLAGS) - 1)

#endif /* !__GENERATING_BOUNDS_H */
#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	8	#include <linux/types.h>
9223b419	9	#ifndef __GENERATING_BOUNDS_H
6d777953	10	#include <linux/mm_types.h>
9223b419 CL	11	#include <linux/bounds.h>
9223b419 CL	12	#endif /* !__GENERATING_BOUNDS_H */
f886ed44	13
1da177e4 LT	14	/*
	15	* Various page->flags bits:
	16	*
	17	* PG_reserved is set for special pages, which can never be swapped out. Some
	18	* of them might not even exist (eg empty_bad_page)...
	19	*
da6052f7 NP	20	* The PG_private bitflag is set on pagecache pages if they contain filesystem
	21	* specific data (which is normally at page->private). It can be used by
	22	* private allocations for its own usage.
1da177e4	23	*
da6052f7 NP	24	* During initiation of disk I/O, PG_locked is set. This bit is set before I/O
	25	* and cleared when writeback _starts_ or when read _completes_. PG_writeback
	26	* is set before writeback starts and cleared when it finishes.
	27	*
	28	* PG_locked also pins a page in pagecache, and blocks truncation of the file
	29	* while it is held.
	30	*
	31	* page_waitqueue(page) is a wait queue of all tasks waiting for the page
	32	* to become unlocked.
1da177e4 LT	33	*
	34	* PG_uptodate tells whether the page's contents is valid. When a read
	35	* completes, the page becomes uptodate, unless a disk I/O error happened.
	36	*
da6052f7 NP	37	* PG_referenced, PG_reclaim are used for page reclaim for anonymous and
da6052f7 NP	38	* file-backed pagecache (see mm/vmscan.c).
1da177e4 LT	39	*
	40	* PG_error is set to indicate that an I/O error occurred on this page.
	41	*
	42	* PG_arch_1 is an architecture specific page state bit. The generic code
	43	* guarantees that this bit is cleared for a page when it first is entered into
	44	* the page cache.
	45	*
	46	* PG_highmem pages are not permanently mapped into the kernel virtual address
	47	* space, they need to be kmapped separately for doing IO on the pages. The
	48	* struct page (these bits with information) are always mapped into kernel
	49	* address space...
da6052f7 NP	50	*
	51	* PG_buddy is set to indicate that the page is free and in the buddy system
	52	* (see mm/page_alloc.c).
	53	*
1da177e4 LT	54	*/
	55
	56	/*
	57	* Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
91fc8ab3 AW	58	* locked- and dirty-page accounting.
	59	*
	60	* The page flags field is split into two parts, the main flags area
	61	* which extends from the low bits upwards, and the fields area which
	62	* extends from the high bits downwards.
	63	*
	64	* \| FIELD \| ... \| FLAGS \|
9223b419 CL	65	* N-1 ^ 0
9223b419 CL	66	* (NR_PAGEFLAGS)
91fc8ab3	67	*
9223b419 CL	68	* The fields area is reserved for fields mapping zone, node (for NUMA) and
	69	* SPARSEMEM section (for variants of SPARSEMEM that require section ids like
	70	* SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
1da177e4	71	*/
e2683181 CL	72	enum pageflags {
	73	PG_locked, /* Page is locked. Don't touch. */
	74	PG_error,
	75	PG_referenced,
	76	PG_uptodate,
	77	PG_dirty,
	78	PG_lru,
	79	PG_active,
	80	PG_slab,
	81	PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
e2683181 CL	82	PG_arch_1,
	83	PG_reserved,
	84	PG_private, /* If pagecache, has fs-private data */
	85	PG_writeback, /* Page is under writeback */
e20b8cca CL	86	#ifdef CONFIG_PAGEFLAGS_EXTENDED
	87	PG_head, /* A head page */
	88	PG_tail, /* A tail page */
	89	#else
e2683181	90	PG_compound, /* A compound page */
e20b8cca	91	#endif
e2683181 CL	92	PG_swapcache, /* Swap page: swp_entry_t in private */
	93	PG_mappedtodisk, /* Has blocks allocated on-disk */
	94	PG_reclaim, /* To be reclaimed asap */
e2683181	95	PG_buddy, /* Page is free, on buddy lists */
b2e18538	96	PG_swapbacked, /* Page is backed by RAM/swap */
894bc310 LS	97	#ifdef CONFIG_UNEVICTABLE_LRU
894bc310 LS	98	PG_unevictable, /* Page is "unevictable" */
33925b25 DH	99	#endif
33925b25 DH	100	#ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
b291f000	101	PG_mlocked, /* Page is vma mlocked */
894bc310	102	#endif
602c4d11 CL	103	#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
602c4d11 CL	104	PG_uncached, /* Page has been mapped as uncached */
f886ed44	105	#endif
0cad47cf AW	106	__NR_PAGEFLAGS,
	107
	108	/* Filesystems */
	109	PG_checked = PG_owner_priv_1,
	110
	111	/* XEN */
	112	PG_pinned = PG_owner_priv_1,
	113	PG_savepinned = PG_dirty,
8a38082d	114
9023cb7e AW	115	/* SLOB */
	116	PG_slob_page = PG_active,
	117	PG_slob_free = PG_private,
	118
8a38082d AW	119	/* SLUB */
	120	PG_slub_frozen = PG_active,
	121	PG_slub_debug = PG_error,
e2683181	122	};
1da177e4	123
9223b419 CL	124	#ifndef __GENERATING_BOUNDS_H
9223b419 CL	125
f94a62e9 CL	126	/*
	127	* Macros to create function definitions for page flags
	128	*/
	129	#define TESTPAGEFLAG(uname, lname) \
	130	static inline int Page##uname(struct page *page) \
	131	{ return test_bit(PG_##lname, &page->flags); }
	132
	133	#define SETPAGEFLAG(uname, lname) \
	134	static inline void SetPage##uname(struct page *page) \
	135	{ set_bit(PG_##lname, &page->flags); }
	136
	137	#define CLEARPAGEFLAG(uname, lname) \
	138	static inline void ClearPage##uname(struct page *page) \
	139	{ clear_bit(PG_##lname, &page->flags); }
	140
	141	#define __SETPAGEFLAG(uname, lname) \
	142	static inline void __SetPage##uname(struct page *page) \
	143	{ __set_bit(PG_##lname, &page->flags); }
	144
	145	#define __CLEARPAGEFLAG(uname, lname) \
	146	static inline void __ClearPage##uname(struct page *page) \
	147	{ __clear_bit(PG_##lname, &page->flags); }
	148
	149	#define TESTSETFLAG(uname, lname) \
	150	static inline int TestSetPage##uname(struct page *page) \
	151	{ return test_and_set_bit(PG_##lname, &page->flags); }
	152
	153	#define TESTCLEARFLAG(uname, lname) \
	154	static inline int TestClearPage##uname(struct page *page) \
	155	{ return test_and_clear_bit(PG_##lname, &page->flags); }
	156
	157
	158	#define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \
	159	SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname)
	160
	161	#define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \
	162	__SETPAGEFLAG(uname, lname) __CLEARPAGEFLAG(uname, lname)
	163
ec7cade8 CL	164	#define PAGEFLAG_FALSE(uname) \
	165	static inline int Page##uname(struct page *page) \
	166	{ return 0; }
	167
f94a62e9 CL	168	#define TESTSCFLAG(uname, lname) \
	169	TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname)
	170
8a7a8544 LS	171	#define SETPAGEFLAG_NOOP(uname) \
	172	static inline void SetPage##uname(struct page *page) { }
	173
	174	#define CLEARPAGEFLAG_NOOP(uname) \
	175	static inline void ClearPage##uname(struct page *page) { }
	176
	177	#define __CLEARPAGEFLAG_NOOP(uname) \
	178	static inline void __ClearPage##uname(struct page *page) { }
	179
	180	#define TESTCLEARFLAG_FALSE(uname) \
	181	static inline int TestClearPage##uname(struct page *page) { return 0; }
	182
6a1e7f77 CL	183	struct page; /* forward declaration */
6a1e7f77 CL	184
529ae9aa	185	TESTPAGEFLAG(Locked, locked)
6a1e7f77 CL	186	PAGEFLAG(Error, error)
	187	PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced)
	188	PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty)
	189	PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru)
	190	PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active)
894bc310	191	TESTCLEARFLAG(Active, active)
6a1e7f77	192	__PAGEFLAG(Slab, slab)
0cad47cf AW	193	PAGEFLAG(Checked, checked) /* Used by some filesystems */
	194	PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */
	195	PAGEFLAG(SavePinned, savepinned); /* Xen */
6a1e7f77 CL	196	PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
	197	PAGEFLAG(Private, private) __CLEARPAGEFLAG(Private, private)
	198	__SETPAGEFLAG(Private, private)
b2e18538	199	PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
6a1e7f77	200
9023cb7e AW	201	__PAGEFLAG(SlobPage, slob_page)
	202	__PAGEFLAG(SlobFree, slob_free)
	203
8a38082d AW	204	__PAGEFLAG(SlubFrozen, slub_frozen)
	205	__PAGEFLAG(SlubDebug, slub_debug)
	206
6a1e7f77 CL	207	/*
	208	* Only test-and-set exist for PG_writeback. The unconditional operators are
	209	* risky: they bypass page accounting.
	210	*/
	211	TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback)
	212	__PAGEFLAG(Buddy, buddy)
	213	PAGEFLAG(MappedToDisk, mappedtodisk)
	214
	215	/* PG_readahead is only used for file reads; PG_reclaim is only for writes */
	216	PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim)
0a128b2b	217	PAGEFLAG(Readahead, reclaim) /* Reminder to do async read-ahead */
6a1e7f77 CL	218
6a1e7f77 CL	219	#ifdef CONFIG_HIGHMEM
1da177e4	220	/*
6a1e7f77 CL	221	* Must use a macro here due to header dependency issues. page_zone() is not
6a1e7f77 CL	222	* available at this point.
1da177e4	223	*/
0a128b2b	224	#define PageHighMem(__p) is_highmem(page_zone(__p))
6a1e7f77	225	#else
ec7cade8	226	PAGEFLAG_FALSE(HighMem)
6a1e7f77 CL	227	#endif
	228
	229	#ifdef CONFIG_SWAP
	230	PAGEFLAG(SwapCache, swapcache)
	231	#else
ec7cade8	232	PAGEFLAG_FALSE(SwapCache)
6d91add0	233	SETPAGEFLAG_NOOP(SwapCache) CLEARPAGEFLAG_NOOP(SwapCache)
6a1e7f77 CL	234	#endif
6a1e7f77 CL	235
894bc310 LS	236	#ifdef CONFIG_UNEVICTABLE_LRU
	237	PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable)
	238	TESTCLEARFLAG(Unevictable, unevictable)
33925b25 DH	239	#else
	240	PAGEFLAG_FALSE(Unevictable) TESTCLEARFLAG_FALSE(Unevictable)
	241	SETPAGEFLAG_NOOP(Unevictable) CLEARPAGEFLAG_NOOP(Unevictable)
	242	__CLEARPAGEFLAG_NOOP(Unevictable)
	243	#endif
b291f000	244
33925b25	245	#ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
b291f000 NP	246	#define MLOCK_PAGES 1
	247	PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked)
	248	TESTSCFLAG(Mlocked, mlocked)
894bc310	249	#else
b291f000 NP	250	#define MLOCK_PAGES 0
	251	PAGEFLAG_FALSE(Mlocked)
	252	SETPAGEFLAG_NOOP(Mlocked) TESTCLEARFLAG_FALSE(Mlocked)
894bc310 LS	253	#endif
894bc310 LS	254
602c4d11	255	#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
6a1e7f77	256	PAGEFLAG(Uncached, uncached)
602c4d11	257	#else
ec7cade8	258	PAGEFLAG_FALSE(Uncached)
6a1e7f77	259	#endif
1da177e4	260
0ed361de NP	261	static inline int PageUptodate(struct page *page)
	262	{
	263	int ret = test_bit(PG_uptodate, &(page)->flags);
	264
	265	/*
	266	* Must ensure that the data we read out of the page is loaded
	267	* _after_ we've loaded page->flags to check for PageUptodate.
	268	* We can skip the barrier if the page is not uptodate, because
	269	* we wouldn't be reading anything from it.
	270	*
	271	* See SetPageUptodate() for the other side of the story.
	272	*/
	273	if (ret)
	274	smp_rmb();
	275
	276	return ret;
	277	}
	278
	279	static inline void __SetPageUptodate(struct page *page)
	280	{
	281	smp_wmb();
	282	__set_bit(PG_uptodate, &(page)->flags);
0ed361de NP	283	}
0ed361de NP	284
2dcea57a HC	285	static inline void SetPageUptodate(struct page *page)
2dcea57a HC	286	{
0ed361de	287	#ifdef CONFIG_S390
2dcea57a	288	if (!test_and_set_bit(PG_uptodate, &page->flags))
6c210482	289	page_clear_dirty(page);
f6ac2354	290	#else
0ed361de NP	291	/*
	292	* Memory barrier must be issued before setting the PG_uptodate bit,
	293	* so that all previous stores issued in order to bring the page
	294	* uptodate are actually visible before PageUptodate becomes true.
	295	*
	296	* s390 doesn't need an explicit smp_wmb here because the test and
	297	* set bit already provides full barriers.
	298	*/
	299	smp_wmb();
	300	set_bit(PG_uptodate, &(page)->flags);
1da177e4	301	#endif
0ed361de NP	302	}
0ed361de NP	303
6a1e7f77	304	CLEARPAGEFLAG(Uptodate, uptodate)
1da177e4	305
6a1e7f77	306	extern void cancel_dirty_page(struct page *page, unsigned int account_size);
d77c2d7c	307
6a1e7f77 CL	308	int test_clear_page_writeback(struct page *page);
6a1e7f77 CL	309	int test_set_page_writeback(struct page *page);
1da177e4	310
6a1e7f77 CL	311	static inline void set_page_writeback(struct page *page)
	312	{
	313	test_set_page_writeback(page);
	314	}
1da177e4	315
e20b8cca CL	316	#ifdef CONFIG_PAGEFLAGS_EXTENDED
	317	/*
	318	* System with lots of page flags available. This allows separate
	319	* flags for PageHead() and PageTail() checks of compound pages so that bit
	320	* tests can be used in performance sensitive paths. PageCompound is
	321	* generally not used in hot code paths.
	322	*/
	323	__PAGEFLAG(Head, head)
	324	__PAGEFLAG(Tail, tail)
	325
	326	static inline int PageCompound(struct page *page)
	327	{
	328	return page->flags & ((1L << PG_head) \| (1L << PG_tail));
	329
	330	}
	331	#else
	332	/*
	333	* Reduce page flag use as much as possible by overlapping
	334	* compound page flags with the flags used for page cache pages. Possible
	335	* because PageCompound is always set for compound pages and not for
	336	* pages on the LRU and/or pagecache.
	337	*/
6a1e7f77 CL	338	TESTPAGEFLAG(Compound, compound)
6a1e7f77 CL	339	__PAGEFLAG(Head, compound)
1da177e4	340
d85f3385	341	/*
6d777953	342	* PG_reclaim is used in combination with PG_compound to mark the
6a1e7f77 CL	343	* head and tail of a compound page. This saves one page flag
	344	* but makes it impossible to use compound pages for the page cache.
	345	* The PG_reclaim bit would have to be used for reclaim or readahead
	346	* if compound pages enter the page cache.
6d777953 CL	347	*
	348	* PG_compound & PG_reclaim => Tail page
	349	* PG_compound & ~PG_reclaim => Head page
d85f3385	350	*/
6d777953 CL	351	#define PG_head_tail_mask ((1L << PG_compound) \| (1L << PG_reclaim))
6d777953 CL	352
6a1e7f77 CL	353	static inline int PageTail(struct page *page)
	354	{
	355	return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask);
	356	}
6d777953 CL	357
	358	static inline void __SetPageTail(struct page *page)
	359	{
	360	page->flags \|= PG_head_tail_mask;
	361	}
	362
	363	static inline void __ClearPageTail(struct page *page)
	364	{
	365	page->flags &= ~PG_head_tail_mask;
	366	}
	367
e20b8cca	368	#endif /* !PAGEFLAGS_EXTENDED */
dfa7e20c	369
894bc310	370	#ifdef CONFIG_UNEVICTABLE_LRU
b291f000	371	#define __PG_UNEVICTABLE (1 << PG_unevictable)
894bc310	372	#else
b291f000	373	#define __PG_UNEVICTABLE 0
33925b25 DH	374	#endif
	375
	376	#ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
	377	#define __PG_MLOCKED (1 << PG_mlocked)
	378	#else
b291f000	379	#define __PG_MLOCKED 0
894bc310 LS	380	#endif
894bc310 LS	381
dfa7e20c RA	382	/*
	383	* Flags checked when a page is freed. Pages being freed should not have
	384	* these flags set. It they are, there is a problem.
	385	*/
79f4b7bf HD	386	#define PAGE_FLAGS_CHECK_AT_FREE \
	387	(1 << PG_lru \| 1 << PG_private \| 1 << PG_locked \| \
	388	1 << PG_buddy \| 1 << PG_writeback \| 1 << PG_reserved \| \
	389	1 << PG_slab \| 1 << PG_swapcache \| 1 << PG_active \| \
	390	__PG_UNEVICTABLE \| __PG_MLOCKED)
dfa7e20c RA	391
	392	/*
	393	* Flags checked when a page is prepped for return by the page allocator.
79f4b7bf HD	394	* Pages being prepped should not have any flags set. It they are set,
79f4b7bf HD	395	* there has been a kernel bug or struct page corruption.
dfa7e20c	396	*/
79f4b7bf	397	#define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1)
dfa7e20c	398
9223b419	399	#endif /* !__GENERATING_BOUNDS_H */
1da177e4	400	#endif /* PAGE_FLAGS_H */