[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>
#include <linux/bug.h>
#include <linux/mmdebug.h>
#ifndef __GENERATING_BOUNDS_H
#include <linux/mm_types.h>
#include <generated/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_hwpoison indicates that a page got corrupted in hardware and contains
 * data with incorrect ECC bits that triggered a machine check. Accessing is
 * not safe since it may cause another machine check. Don't touch!
 */

/*
 * 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_private_2,		/* If pagecache, has fs aux 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_swapbacked,		/* Page is backed by RAM/swap */
	PG_unevictable,		/* Page is "unevictable"  */
#ifdef CONFIG_MMU
	PG_mlocked,		/* Page is vma mlocked */
#endif
#ifdef CONFIG_ARCH_USES_PG_UNCACHED
	PG_uncached,		/* Page has been mapped as uncached */
#endif
#ifdef CONFIG_MEMORY_FAILURE
	PG_hwpoison,		/* hardware poisoned page. Don't touch */
#endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	PG_compound_lock,
#endif
	__NR_PAGEFLAGS,

	/* Filesystems */
	PG_checked = PG_owner_priv_1,

	/* Two page bits are conscripted by FS-Cache to maintain local caching
	 * state.  These bits are set on pages belonging to the netfs's inodes
	 * when those inodes are being locally cached.
	 */
	PG_fscache = PG_private_2,	/* page backed by cache */

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

	/* SLOB */
	PG_slob_free = PG_private,
};

#ifndef __GENERATING_BOUNDS_H

/*
 * Macros to create function definitions for page flags
 */
#define TESTPAGEFLAG(uname, lname)					\
static inline int Page##uname(const 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 __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 TESTSCFLAG(uname, lname)					\
	TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname)

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

#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 TESTSETFLAG_FALSE(uname)					\
static inline int TestSetPage##uname(struct page *page) { return 0; }

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

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

#define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname)			\
	SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname)

#define TESTSCFLAG_FALSE(uname)						\
	TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)

struct page;	/* forward declaration */

TESTPAGEFLAG(Locked, locked)
PAGEFLAG(Error, error) TESTCLEARFLAG(Error, error)
PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced)
	__SETPAGEFLAG(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(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
	__SETPAGEFLAG(SwapBacked, swapbacked)

__PAGEFLAG(SlobFree, slob_free)

/*
 * Private page markings that may be used by the filesystem that owns the page
 * for its own purposes.
 * - PG_private and PG_private_2 cause releasepage() and co to be invoked
 */
PAGEFLAG(Private, private) __SETPAGEFLAG(Private, private)
	__CLEARPAGEFLAG(Private, private)
PAGEFLAG(Private2, private_2) TESTSCFLAG(Private2, private_2)
PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1)

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

/* PG_readahead is only used for reads; PG_reclaim is only for writes */
PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim)
PAGEFLAG(Readahead, reclaim) TESTCLEARFLAG(Readahead, reclaim)

#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)
#endif

PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable)
	TESTCLEARFLAG(Unevictable, unevictable)

#ifdef CONFIG_MMU
PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked)
	TESTSCFLAG(Mlocked, mlocked) __TESTCLEARFLAG(Mlocked, mlocked)
#else
PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked)
	TESTSCFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked)
#endif

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

#ifdef CONFIG_MEMORY_FAILURE
PAGEFLAG(HWPoison, hwpoison)
TESTSCFLAG(HWPoison, hwpoison)
#define __PG_HWPOISON (1UL << PG_hwpoison)
#else
PAGEFLAG_FALSE(HWPoison)
#define __PG_HWPOISON 0
#endif

u64 stable_page_flags(struct page *page);

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)
{
	/*
	 * 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.
	 */
	smp_wmb();
	set_bit(PG_uptodate, &(page)->flags);
}

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, bool keep_write);

#define test_set_page_writeback(page)			\
	__test_set_page_writeback(page, false)
#define test_set_page_writeback_keepwrite(page)	\
	__test_set_page_writeback(page, true)

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

static inline void set_page_writeback_keepwrite(struct page *page)
{
	test_set_page_writeback_keepwrite(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 except arch/powerpc/mm/init_64.c
 * and arch/powerpc/kvm/book3s_64_vio_hv.c which use it to detect huge pages
 * and avoid handling those in real mode.
 */
__PAGEFLAG(Head, head) CLEARPAGEFLAG(Head, head)
__PAGEFLAG(Tail, tail)

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

}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline void ClearPageCompound(struct page *page)
{
	BUG_ON(!PageHead(page));
	ClearPageHead(page);
}
#endif

#define PG_head_mask ((1L << PG_head))

#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)
__SETPAGEFLAG(Head, compound)  __CLEARPAGEFLAG(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_mask ((1L << PG_compound))
#define PG_head_tail_mask ((1L << PG_compound) | (1L << PG_reclaim))

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

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;
}

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline void ClearPageCompound(struct page *page)
{
	BUG_ON((page->flags & PG_head_tail_mask) != (1 << PG_compound));
	clear_bit(PG_compound, &page->flags);
}
#endif

#endif /* !PAGEFLAGS_EXTENDED */

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/*
 * PageHuge() only returns true for hugetlbfs pages, but not for
 * normal or transparent huge pages.
 *
 * PageTransHuge() returns true for both transparent huge and
 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
 * called only in the core VM paths where hugetlbfs pages can't exist.
 */
static inline int PageTransHuge(struct page *page)
{
	VM_BUG_ON_PAGE(PageTail(page), page);
	return PageHead(page);
}

/*
 * PageTransCompound returns true for both transparent huge pages
 * and hugetlbfs pages, so it should only be called when it's known
 * that hugetlbfs pages aren't involved.
 */
static inline int PageTransCompound(struct page *page)
{
	return PageCompound(page);
}

/*
 * PageTransTail returns true for both transparent huge pages
 * and hugetlbfs pages, so it should only be called when it's known
 * that hugetlbfs pages aren't involved.
 */
static inline int PageTransTail(struct page *page)
{
	return PageTail(page);
}

#else

static inline int PageTransHuge(struct page *page)
{
	return 0;
}

static inline int PageTransCompound(struct page *page)
{
	return 0;
}

static inline int PageTransTail(struct page *page)
{
	return 0;
}
#endif

/*
 * If network-based swap is enabled, sl*b must keep track of whether pages
 * were allocated from pfmemalloc reserves.
 */
static inline int PageSlabPfmemalloc(struct page *page)
{
	VM_BUG_ON_PAGE(!PageSlab(page), page);
	return PageActive(page);
}

static inline void SetPageSlabPfmemalloc(struct page *page)
{
	VM_BUG_ON_PAGE(!PageSlab(page), page);
	SetPageActive(page);
}

static inline void __ClearPageSlabPfmemalloc(struct page *page)
{
	VM_BUG_ON_PAGE(!PageSlab(page), page);
	__ClearPageActive(page);
}

static inline void ClearPageSlabPfmemalloc(struct page *page)
{
	VM_BUG_ON_PAGE(!PageSlab(page), page);
	ClearPageActive(page);
}

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

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define __PG_COMPOUND_LOCK		(1 << PG_compound_lock)
#else
#define __PG_COMPOUND_LOCK		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_locked    | \
	 1 << PG_private | 1 << PG_private_2 | \
	 1 << PG_writeback | 1 << PG_reserved | \
	 1 << PG_slab	 | 1 << PG_swapcache | 1 << PG_active | \
	 1 << PG_unevictable | __PG_MLOCKED | __PG_HWPOISON | \
	 __PG_COMPOUND_LOCK)

/*
 * 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)

#define PAGE_FLAGS_PRIVATE				\
	(1 << PG_private | 1 << PG_private_2)
/**
 * page_has_private - Determine if page has private stuff
 * @page: The page to be checked
 *
 * Determine if a page has private stuff, indicating that release routines
 * should be invoked upon it.
 */
static inline int page_has_private(struct page *page)
{
	return !!(page->flags & PAGE_FLAGS_PRIVATE);
}

#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>
187f1882	9	#include <linux/bug.h>
072bb0aa	10	#include <linux/mmdebug.h>
9223b419	11	#ifndef __GENERATING_BOUNDS_H
6d777953	12	#include <linux/mm_types.h>
01fc0ac1	13	#include <generated/bounds.h>
9223b419	14	#endif /* !__GENERATING_BOUNDS_H */
f886ed44	15
1da177e4 LT	16	/*
	17	* Various page->flags bits:
	18	*
	19	* PG_reserved is set for special pages, which can never be swapped out. Some
	20	* of them might not even exist (eg empty_bad_page)...
	21	*
da6052f7 NP	22	* The PG_private bitflag is set on pagecache pages if they contain filesystem
	23	* specific data (which is normally at page->private). It can be used by
	24	* private allocations for its own usage.
1da177e4	25	*
da6052f7 NP	26	* During initiation of disk I/O, PG_locked is set. This bit is set before I/O
	27	* and cleared when writeback _starts_ or when read _completes_. PG_writeback
	28	* is set before writeback starts and cleared when it finishes.
	29	*
	30	* PG_locked also pins a page in pagecache, and blocks truncation of the file
	31	* while it is held.
	32	*
	33	* page_waitqueue(page) is a wait queue of all tasks waiting for the page
	34	* to become unlocked.
1da177e4 LT	35	*
	36	* PG_uptodate tells whether the page's contents is valid. When a read
	37	* completes, the page becomes uptodate, unless a disk I/O error happened.
	38	*
da6052f7 NP	39	* PG_referenced, PG_reclaim are used for page reclaim for anonymous and
da6052f7 NP	40	* file-backed pagecache (see mm/vmscan.c).
1da177e4 LT	41	*
	42	* PG_error is set to indicate that an I/O error occurred on this page.
	43	*
	44	* PG_arch_1 is an architecture specific page state bit. The generic code
	45	* guarantees that this bit is cleared for a page when it first is entered into
	46	* the page cache.
	47	*
	48	* PG_highmem pages are not permanently mapped into the kernel virtual address
	49	* space, they need to be kmapped separately for doing IO on the pages. The
	50	* struct page (these bits with information) are always mapped into kernel
	51	* address space...
da6052f7	52	*
d466f2fc AK	53	* PG_hwpoison indicates that a page got corrupted in hardware and contains
	54	* data with incorrect ECC bits that triggered a machine check. Accessing is
	55	* not safe since it may cause another machine check. Don't touch!
1da177e4 LT	56	*/
	57
	58	/*
	59	* Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
91fc8ab3 AW	60	* locked- and dirty-page accounting.
	61	*
	62	* The page flags field is split into two parts, the main flags area
	63	* which extends from the low bits upwards, and the fields area which
	64	* extends from the high bits downwards.
	65	*
	66	* \| FIELD \| ... \| FLAGS \|
9223b419 CL	67	* N-1 ^ 0
9223b419 CL	68	* (NR_PAGEFLAGS)
91fc8ab3	69	*
9223b419 CL	70	* The fields area is reserved for fields mapping zone, node (for NUMA) and
	71	* SPARSEMEM section (for variants of SPARSEMEM that require section ids like
	72	* SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
1da177e4	73	*/
e2683181 CL	74	enum pageflags {
	75	PG_locked, /* Page is locked. Don't touch. */
	76	PG_error,
	77	PG_referenced,
	78	PG_uptodate,
	79	PG_dirty,
	80	PG_lru,
	81	PG_active,
	82	PG_slab,
	83	PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
e2683181 CL	84	PG_arch_1,
	85	PG_reserved,
	86	PG_private, /* If pagecache, has fs-private data */
266cf658	87	PG_private_2, /* If pagecache, has fs aux data */
e2683181	88	PG_writeback, /* Page is under writeback */
e20b8cca CL	89	#ifdef CONFIG_PAGEFLAGS_EXTENDED
	90	PG_head, /* A head page */
	91	PG_tail, /* A tail page */
	92	#else
e2683181	93	PG_compound, /* A compound page */
e20b8cca	94	#endif
e2683181 CL	95	PG_swapcache, /* Swap page: swp_entry_t in private */
	96	PG_mappedtodisk, /* Has blocks allocated on-disk */
	97	PG_reclaim, /* To be reclaimed asap */
b2e18538	98	PG_swapbacked, /* Page is backed by RAM/swap */
894bc310	99	PG_unevictable, /* Page is "unevictable" */
af8e3354	100	#ifdef CONFIG_MMU
b291f000	101	PG_mlocked, /* Page is vma mlocked */
894bc310	102	#endif
46cf98cd	103	#ifdef CONFIG_ARCH_USES_PG_UNCACHED
602c4d11	104	PG_uncached, /* Page has been mapped as uncached */
d466f2fc AK	105	#endif
	106	#ifdef CONFIG_MEMORY_FAILURE
	107	PG_hwpoison, /* hardware poisoned page. Don't touch */
e9da73d6 AA	108	#endif
	109	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	110	PG_compound_lock,
f886ed44	111	#endif
0cad47cf AW	112	__NR_PAGEFLAGS,
	113
	114	/* Filesystems */
	115	PG_checked = PG_owner_priv_1,
	116
266cf658 DH	117	/* Two page bits are conscripted by FS-Cache to maintain local caching
	118	* state. These bits are set on pages belonging to the netfs's inodes
	119	* when those inodes are being locally cached.
	120	*/
	121	PG_fscache = PG_private_2, /* page backed by cache */
	122
0cad47cf AW	123	/* XEN */
	124	PG_pinned = PG_owner_priv_1,
	125	PG_savepinned = PG_dirty,
8a38082d	126
9023cb7e	127	/* SLOB */
9023cb7e	128	PG_slob_free = PG_private,
e2683181	129	};
1da177e4	130
9223b419 CL	131	#ifndef __GENERATING_BOUNDS_H
9223b419 CL	132
f94a62e9 CL	133	/*
	134	* Macros to create function definitions for page flags
	135	*/
	136	#define TESTPAGEFLAG(uname, lname) \
67db392d	137	static inline int Page##uname(const struct page *page) \
f94a62e9 CL	138	{ return test_bit(PG_##lname, &page->flags); }
	139
	140	#define SETPAGEFLAG(uname, lname) \
	141	static inline void SetPage##uname(struct page *page) \
	142	{ set_bit(PG_##lname, &page->flags); }
	143
	144	#define CLEARPAGEFLAG(uname, lname) \
	145	static inline void ClearPage##uname(struct page *page) \
	146	{ clear_bit(PG_##lname, &page->flags); }
	147
	148	#define __SETPAGEFLAG(uname, lname) \
	149	static inline void __SetPage##uname(struct page *page) \
	150	{ __set_bit(PG_##lname, &page->flags); }
	151
	152	#define __CLEARPAGEFLAG(uname, lname) \
	153	static inline void __ClearPage##uname(struct page *page) \
	154	{ __clear_bit(PG_##lname, &page->flags); }
	155
	156	#define TESTSETFLAG(uname, lname) \
	157	static inline int TestSetPage##uname(struct page *page) \
	158	{ return test_and_set_bit(PG_##lname, &page->flags); }
	159
	160	#define TESTCLEARFLAG(uname, lname) \
	161	static inline int TestClearPage##uname(struct page *page) \
	162	{ return test_and_clear_bit(PG_##lname, &page->flags); }
	163
451ea25d JW	164	#define __TESTCLEARFLAG(uname, lname) \
	165	static inline int __TestClearPage##uname(struct page *page) \
	166	{ return __test_and_clear_bit(PG_##lname, &page->flags); }
f94a62e9 CL	167
	168	#define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \
	169	SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname)
	170
	171	#define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \
	172	__SETPAGEFLAG(uname, lname) __CLEARPAGEFLAG(uname, lname)
	173
	174	#define TESTSCFLAG(uname, lname) \
	175	TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname)
	176
2f3e442c JW	177	#define TESTPAGEFLAG_FALSE(uname) \
	178	static inline int Page##uname(const struct page *page) { return 0; }
	179
8a7a8544 LS	180	#define SETPAGEFLAG_NOOP(uname) \
	181	static inline void SetPage##uname(struct page *page) { }
	182
	183	#define CLEARPAGEFLAG_NOOP(uname) \
	184	static inline void ClearPage##uname(struct page *page) { }
	185
	186	#define __CLEARPAGEFLAG_NOOP(uname) \
	187	static inline void __ClearPage##uname(struct page *page) { }
	188
2f3e442c JW	189	#define TESTSETFLAG_FALSE(uname) \
	190	static inline int TestSetPage##uname(struct page *page) { return 0; }
	191
8a7a8544 LS	192	#define TESTCLEARFLAG_FALSE(uname) \
	193	static inline int TestClearPage##uname(struct page *page) { return 0; }
	194
451ea25d JW	195	#define __TESTCLEARFLAG_FALSE(uname) \
	196	static inline int __TestClearPage##uname(struct page *page) { return 0; }
	197
2f3e442c JW	198	#define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \
	199	SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname)
	200
	201	#define TESTSCFLAG_FALSE(uname) \
	202	TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
	203
6a1e7f77 CL	204	struct page; /* forward declaration */
6a1e7f77 CL	205
cb240452	206	TESTPAGEFLAG(Locked, locked)
212260aa	207	PAGEFLAG(Error, error) TESTCLEARFLAG(Error, error)
6a1e7f77	208	PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced)
2457aec6	209	__SETPAGEFLAG(Referenced, referenced)
6a1e7f77 CL	210	PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty)
	211	PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru)
	212	PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active)
894bc310	213	TESTCLEARFLAG(Active, active)
6a1e7f77	214	__PAGEFLAG(Slab, slab)
0cad47cf AW	215	PAGEFLAG(Checked, checked) /* Used by some filesystems */
	216	PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */
	217	PAGEFLAG(SavePinned, savepinned); /* Xen */
6a1e7f77	218	PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
b2e18538	219	PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
07a42788	220	__SETPAGEFLAG(SwapBacked, swapbacked)
6a1e7f77	221
9023cb7e AW	222	__PAGEFLAG(SlobFree, slob_free)
9023cb7e AW	223
266cf658 DH	224	/*
	225	* Private page markings that may be used by the filesystem that owns the page
	226	* for its own purposes.
	227	* - PG_private and PG_private_2 cause releasepage() and co to be invoked
	228	*/
	229	PAGEFLAG(Private, private) __SETPAGEFLAG(Private, private)
	230	__CLEARPAGEFLAG(Private, private)
	231	PAGEFLAG(Private2, private_2) TESTSCFLAG(Private2, private_2)
	232	PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1)
	233
6a1e7f77 CL	234	/*
	235	* Only test-and-set exist for PG_writeback. The unconditional operators are
	236	* risky: they bypass page accounting.
	237	*/
	238	TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback)
6a1e7f77 CL	239	PAGEFLAG(MappedToDisk, mappedtodisk)
6a1e7f77 CL	240
579f8290	241	/* PG_readahead is only used for reads; PG_reclaim is only for writes */
6a1e7f77	242	PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim)
579f8290	243	PAGEFLAG(Readahead, reclaim) TESTCLEARFLAG(Readahead, reclaim)
6a1e7f77 CL	244
6a1e7f77 CL	245	#ifdef CONFIG_HIGHMEM
1da177e4	246	/*
6a1e7f77 CL	247	* Must use a macro here due to header dependency issues. page_zone() is not
6a1e7f77 CL	248	* available at this point.
1da177e4	249	*/
0a128b2b	250	#define PageHighMem(__p) is_highmem(page_zone(__p))
6a1e7f77	251	#else
ec7cade8	252	PAGEFLAG_FALSE(HighMem)
6a1e7f77 CL	253	#endif
	254
	255	#ifdef CONFIG_SWAP
	256	PAGEFLAG(SwapCache, swapcache)
	257	#else
ec7cade8	258	PAGEFLAG_FALSE(SwapCache)
6a1e7f77 CL	259	#endif
6a1e7f77 CL	260
894bc310 LS	261	PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable)
894bc310 LS	262	TESTCLEARFLAG(Unevictable, unevictable)
b291f000	263
af8e3354	264	#ifdef CONFIG_MMU
b291f000	265	PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked)
451ea25d	266	TESTSCFLAG(Mlocked, mlocked) __TESTCLEARFLAG(Mlocked, mlocked)
894bc310	267	#else
2f3e442c JW	268	PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked)
2f3e442c JW	269	TESTSCFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked)
894bc310 LS	270	#endif
894bc310 LS	271
46cf98cd	272	#ifdef CONFIG_ARCH_USES_PG_UNCACHED
6a1e7f77	273	PAGEFLAG(Uncached, uncached)
602c4d11	274	#else
ec7cade8	275	PAGEFLAG_FALSE(Uncached)
6a1e7f77	276	#endif
1da177e4	277
d466f2fc AK	278	#ifdef CONFIG_MEMORY_FAILURE
d466f2fc AK	279	PAGEFLAG(HWPoison, hwpoison)
847ce401	280	TESTSCFLAG(HWPoison, hwpoison)
d466f2fc AK	281	#define __PG_HWPOISON (1UL << PG_hwpoison)
	282	#else
	283	PAGEFLAG_FALSE(HWPoison)
	284	#define __PG_HWPOISON 0
	285	#endif
	286
1a9b5b7f WF	287	u64 stable_page_flags(struct page *page);
1a9b5b7f WF	288
0ed361de NP	289	static inline int PageUptodate(struct page *page)
	290	{
	291	int ret = test_bit(PG_uptodate, &(page)->flags);
	292
	293	/*
	294	* Must ensure that the data we read out of the page is loaded
	295	* _after_ we've loaded page->flags to check for PageUptodate.
	296	* We can skip the barrier if the page is not uptodate, because
	297	* we wouldn't be reading anything from it.
	298	*
	299	* See SetPageUptodate() for the other side of the story.
	300	*/
	301	if (ret)
	302	smp_rmb();
	303
	304	return ret;
	305	}
	306
	307	static inline void __SetPageUptodate(struct page *page)
	308	{
	309	smp_wmb();
	310	__set_bit(PG_uptodate, &(page)->flags);
0ed361de NP	311	}
0ed361de NP	312
2dcea57a HC	313	static inline void SetPageUptodate(struct page *page)
2dcea57a HC	314	{
0ed361de NP	315	/*
	316	* Memory barrier must be issued before setting the PG_uptodate bit,
	317	* so that all previous stores issued in order to bring the page
	318	* uptodate are actually visible before PageUptodate becomes true.
0ed361de NP	319	*/
	320	smp_wmb();
	321	set_bit(PG_uptodate, &(page)->flags);
0ed361de NP	322	}
0ed361de NP	323
6a1e7f77	324	CLEARPAGEFLAG(Uptodate, uptodate)
1da177e4	325
6a1e7f77	326	extern void cancel_dirty_page(struct page *page, unsigned int account_size);
d77c2d7c	327
6a1e7f77	328	int test_clear_page_writeback(struct page *page);
1c8349a1 NJ	329	int __test_set_page_writeback(struct page *page, bool keep_write);
	330
	331	#define test_set_page_writeback(page) \
	332	__test_set_page_writeback(page, false)
	333	#define test_set_page_writeback_keepwrite(page) \
	334	__test_set_page_writeback(page, true)
1da177e4	335
6a1e7f77 CL	336	static inline void set_page_writeback(struct page *page)
	337	{
	338	test_set_page_writeback(page);
	339	}
1da177e4	340
1c8349a1 NJ	341	static inline void set_page_writeback_keepwrite(struct page *page)
	342	{
	343	test_set_page_writeback_keepwrite(page);
	344	}
	345
e20b8cca CL	346	#ifdef CONFIG_PAGEFLAGS_EXTENDED
	347	/*
	348	* System with lots of page flags available. This allows separate
	349	* flags for PageHead() and PageTail() checks of compound pages so that bit
	350	* tests can be used in performance sensitive paths. PageCompound is
8e0861fa AK	351	* generally not used in hot code paths except arch/powerpc/mm/init_64.c
	352	* and arch/powerpc/kvm/book3s_64_vio_hv.c which use it to detect huge pages
	353	* and avoid handling those in real mode.
e20b8cca	354	*/
4e6af67e	355	__PAGEFLAG(Head, head) CLEARPAGEFLAG(Head, head)
e20b8cca CL	356	__PAGEFLAG(Tail, tail)
	357
	358	static inline int PageCompound(struct page *page)
	359	{
	360	return page->flags & ((1L << PG_head) \| (1L << PG_tail));
	361
	362	}
4e6af67e AA	363	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	364	static inline void ClearPageCompound(struct page *page)
	365	{
	366	BUG_ON(!PageHead(page));
	367	ClearPageHead(page);
	368	}
	369	#endif
b3acc56b PT	370
	371	#define PG_head_mask ((1L << PG_head))
	372
e20b8cca CL	373	#else
	374	/*
	375	* Reduce page flag use as much as possible by overlapping
	376	* compound page flags with the flags used for page cache pages. Possible
	377	* because PageCompound is always set for compound pages and not for
	378	* pages on the LRU and/or pagecache.
	379	*/
6a1e7f77	380	TESTPAGEFLAG(Compound, compound)
ad4b3fb7	381	__SETPAGEFLAG(Head, compound) __CLEARPAGEFLAG(Head, compound)
1da177e4	382
d85f3385	383	/*
6d777953	384	* PG_reclaim is used in combination with PG_compound to mark the
6a1e7f77 CL	385	* head and tail of a compound page. This saves one page flag
	386	* but makes it impossible to use compound pages for the page cache.
	387	* The PG_reclaim bit would have to be used for reclaim or readahead
	388	* if compound pages enter the page cache.
6d777953 CL	389	*
	390	* PG_compound & PG_reclaim => Tail page
	391	* PG_compound & ~PG_reclaim => Head page
d85f3385	392	*/
ad4b3fb7	393	#define PG_head_mask ((1L << PG_compound))
6d777953 CL	394	#define PG_head_tail_mask ((1L << PG_compound) \| (1L << PG_reclaim))
6d777953 CL	395
ad4b3fb7 CD	396	static inline int PageHead(struct page *page)
	397	{
	398	return ((page->flags & PG_head_tail_mask) == PG_head_mask);
	399	}
	400
6a1e7f77 CL	401	static inline int PageTail(struct page *page)
	402	{
	403	return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask);
	404	}
6d777953 CL	405
	406	static inline void __SetPageTail(struct page *page)
	407	{
	408	page->flags \|= PG_head_tail_mask;
	409	}
	410
	411	static inline void __ClearPageTail(struct page *page)
	412	{
	413	page->flags &= ~PG_head_tail_mask;
	414	}
	415
4e6af67e AA	416	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	417	static inline void ClearPageCompound(struct page *page)
	418	{
	419	BUG_ON((page->flags & PG_head_tail_mask) != (1 << PG_compound));
	420	clear_bit(PG_compound, &page->flags);
	421	}
	422	#endif
	423
e20b8cca	424	#endif /* !PAGEFLAGS_EXTENDED */
dfa7e20c	425
936a5fe6	426	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
71e3aac0 AA	427	/*
	428	* PageHuge() only returns true for hugetlbfs pages, but not for
	429	* normal or transparent huge pages.
	430	*
	431	* PageTransHuge() returns true for both transparent huge and
	432	* hugetlbfs pages, but not normal pages. PageTransHuge() can only be
	433	* called only in the core VM paths where hugetlbfs pages can't exist.
	434	*/
	435	static inline int PageTransHuge(struct page *page)
	436	{
309381fe	437	VM_BUG_ON_PAGE(PageTail(page), page);
71e3aac0 AA	438	return PageHead(page);
	439	}
	440
385de357 DN	441	/*
	442	* PageTransCompound returns true for both transparent huge pages
	443	* and hugetlbfs pages, so it should only be called when it's known
	444	* that hugetlbfs pages aren't involved.
	445	*/
936a5fe6 AA	446	static inline int PageTransCompound(struct page *page)
	447	{
	448	return PageCompound(page);
	449	}
71e3aac0	450
385de357 DN	451	/*
	452	* PageTransTail returns true for both transparent huge pages
	453	* and hugetlbfs pages, so it should only be called when it's known
	454	* that hugetlbfs pages aren't involved.
	455	*/
	456	static inline int PageTransTail(struct page *page)
	457	{
	458	return PageTail(page);
	459	}
	460
936a5fe6	461	#else
71e3aac0 AA	462
	463	static inline int PageTransHuge(struct page *page)
	464	{
	465	return 0;
	466	}
	467
936a5fe6 AA	468	static inline int PageTransCompound(struct page *page)
	469	{
	470	return 0;
	471	}
385de357 DN	472
	473	static inline int PageTransTail(struct page *page)
	474	{
	475	return 0;
	476	}
936a5fe6 AA	477	#endif
936a5fe6 AA	478
072bb0aa MG	479	/*
	480	* If network-based swap is enabled, sl*b must keep track of whether pages
	481	* were allocated from pfmemalloc reserves.
	482	*/
	483	static inline int PageSlabPfmemalloc(struct page *page)
	484	{
309381fe	485	VM_BUG_ON_PAGE(!PageSlab(page), page);
072bb0aa MG	486	return PageActive(page);
	487	}
	488
	489	static inline void SetPageSlabPfmemalloc(struct page *page)
	490	{
309381fe	491	VM_BUG_ON_PAGE(!PageSlab(page), page);
072bb0aa MG	492	SetPageActive(page);
	493	}
	494
	495	static inline void __ClearPageSlabPfmemalloc(struct page *page)
	496	{
309381fe	497	VM_BUG_ON_PAGE(!PageSlab(page), page);
072bb0aa MG	498	__ClearPageActive(page);
	499	}
	500
	501	static inline void ClearPageSlabPfmemalloc(struct page *page)
	502	{
309381fe	503	VM_BUG_ON_PAGE(!PageSlab(page), page);
072bb0aa MG	504	ClearPageActive(page);
	505	}
	506
af8e3354	507	#ifdef CONFIG_MMU
33925b25 DH	508	#define __PG_MLOCKED (1 << PG_mlocked)
33925b25 DH	509	#else
b291f000	510	#define __PG_MLOCKED 0
894bc310 LS	511	#endif
894bc310 LS	512
e9da73d6 AA	513	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	514	#define __PG_COMPOUND_LOCK (1 << PG_compound_lock)
	515	#else
	516	#define __PG_COMPOUND_LOCK 0
	517	#endif
	518
dfa7e20c RA	519	/*
	520	* Flags checked when a page is freed. Pages being freed should not have
	521	* these flags set. It they are, there is a problem.
	522	*/
79f4b7bf	523	#define PAGE_FLAGS_CHECK_AT_FREE \
266cf658 DH	524	(1 << PG_lru \| 1 << PG_locked \| \
266cf658 DH	525	1 << PG_private \| 1 << PG_private_2 \| \
5f24ce5f	526	1 << PG_writeback \| 1 << PG_reserved \| \
266cf658	527	1 << PG_slab \| 1 << PG_swapcache \| 1 << PG_active \| \
e9da73d6 AA	528	1 << PG_unevictable \| __PG_MLOCKED \| __PG_HWPOISON \| \
e9da73d6 AA	529	__PG_COMPOUND_LOCK)
dfa7e20c RA	530
	531	/*
	532	* Flags checked when a page is prepped for return by the page allocator.
79f4b7bf HD	533	* Pages being prepped should not have any flags set. It they are set,
79f4b7bf HD	534	* there has been a kernel bug or struct page corruption.
dfa7e20c	535	*/
79f4b7bf	536	#define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1)
dfa7e20c	537
edcf4748 JW	538	#define PAGE_FLAGS_PRIVATE \
edcf4748 JW	539	(1 << PG_private \| 1 << PG_private_2)
266cf658 DH	540	/**
	541	* page_has_private - Determine if page has private stuff
	542	* @page: The page to be checked
	543	*
	544	* Determine if a page has private stuff, indicating that release routines
	545	* should be invoked upon it.
	546	*/
edcf4748 JW	547	static inline int page_has_private(struct page *page)
	548	{
	549	return !!(page->flags & PAGE_FLAGS_PRIVATE);
	550	}
	551
	552	#endif /* !__GENERATING_BOUNDS_H */
266cf658	553
1da177e4	554	#endif /* PAGE_FLAGS_H */