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Diffstat (limited to 'include/linux/page-flags.h')
| -rw-r--r-- | include/linux/page-flags.h | 804 |
1 files changed, 804 insertions, 0 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h new file mode 100644 index 000000000..f6e943366 --- /dev/null +++ b/include/linux/page-flags.h @@ -0,0 +1,804 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * 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... + * + * 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_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_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */ + 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 */ + PG_head, /* A head page */ + 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 +#if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT) + PG_young, + PG_idle, +#endif + __NR_PAGEFLAGS, + + /* Filesystems */ + PG_checked = PG_owner_priv_1, + + /* SwapBacked */ + PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */ + + /* 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 */ + /* Pinned in Xen as a read-only pagetable page. */ + PG_pinned = PG_owner_priv_1, + /* Pinned as part of domain save (see xen_mm_pin_all()). */ + PG_savepinned = PG_dirty, + /* Has a grant mapping of another (foreign) domain's page. */ + PG_foreign = PG_owner_priv_1, + + /* SLOB */ + PG_slob_free = PG_private, + + /* Compound pages. Stored in first tail page's flags */ + PG_double_map = PG_private_2, + + /* non-lru isolated movable page */ + PG_isolated = PG_reclaim, +}; + +#ifndef __GENERATING_BOUNDS_H + +struct page; /* forward declaration */ + +static inline struct page *compound_head(struct page *page) +{ + unsigned long head = READ_ONCE(page->compound_head); + + if (unlikely(head & 1)) + return (struct page *) (head - 1); + return page; +} + +static __always_inline int PageTail(struct page *page) +{ + return READ_ONCE(page->compound_head) & 1; +} + +static __always_inline int PageCompound(struct page *page) +{ + return test_bit(PG_head, &page->flags) || PageTail(page); +} + +#define PAGE_POISON_PATTERN -1l +static inline int PagePoisoned(const struct page *page) +{ + return page->flags == PAGE_POISON_PATTERN; +} + +/* + * Page flags policies wrt compound pages + * + * PF_POISONED_CHECK + * check if this struct page poisoned/uninitialized + * + * PF_ANY: + * the page flag is relevant for small, head and tail pages. + * + * PF_HEAD: + * for compound page all operations related to the page flag applied to + * head page. + * + * PF_ONLY_HEAD: + * for compound page, callers only ever operate on the head page. + * + * PF_NO_TAIL: + * modifications of the page flag must be done on small or head pages, + * checks can be done on tail pages too. + * + * PF_NO_COMPOUND: + * the page flag is not relevant for compound pages. + */ +#define PF_POISONED_CHECK(page) ({ \ + VM_BUG_ON_PGFLAGS(PagePoisoned(page), page); \ + page; }) +#define PF_ANY(page, enforce) PF_POISONED_CHECK(page) +#define PF_HEAD(page, enforce) PF_POISONED_CHECK(compound_head(page)) +#define PF_ONLY_HEAD(page, enforce) ({ \ + VM_BUG_ON_PGFLAGS(PageTail(page), page); \ + PF_POISONED_CHECK(page); }) +#define PF_NO_TAIL(page, enforce) ({ \ + VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \ + PF_POISONED_CHECK(compound_head(page)); }) +#define PF_NO_COMPOUND(page, enforce) ({ \ + VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \ + PF_POISONED_CHECK(page); }) + +/* + * Macros to create function definitions for page flags + */ +#define TESTPAGEFLAG(uname, lname, policy) \ +static __always_inline int Page##uname(struct page *page) \ + { return test_bit(PG_##lname, &policy(page, 0)->flags); } + +#define SETPAGEFLAG(uname, lname, policy) \ +static __always_inline void SetPage##uname(struct page *page) \ + { set_bit(PG_##lname, &policy(page, 1)->flags); } + +#define CLEARPAGEFLAG(uname, lname, policy) \ +static __always_inline void ClearPage##uname(struct page *page) \ + { clear_bit(PG_##lname, &policy(page, 1)->flags); } + +#define __SETPAGEFLAG(uname, lname, policy) \ +static __always_inline void __SetPage##uname(struct page *page) \ + { __set_bit(PG_##lname, &policy(page, 1)->flags); } + +#define __CLEARPAGEFLAG(uname, lname, policy) \ +static __always_inline void __ClearPage##uname(struct page *page) \ + { __clear_bit(PG_##lname, &policy(page, 1)->flags); } + +#define TESTSETFLAG(uname, lname, policy) \ +static __always_inline int TestSetPage##uname(struct page *page) \ + { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); } + +#define TESTCLEARFLAG(uname, lname, policy) \ +static __always_inline int TestClearPage##uname(struct page *page) \ + { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); } + +#define PAGEFLAG(uname, lname, policy) \ + TESTPAGEFLAG(uname, lname, policy) \ + SETPAGEFLAG(uname, lname, policy) \ + CLEARPAGEFLAG(uname, lname, policy) + +#define __PAGEFLAG(uname, lname, policy) \ + TESTPAGEFLAG(uname, lname, policy) \ + __SETPAGEFLAG(uname, lname, policy) \ + __CLEARPAGEFLAG(uname, lname, policy) + +#define TESTSCFLAG(uname, lname, policy) \ + TESTSETFLAG(uname, lname, policy) \ + TESTCLEARFLAG(uname, lname, policy) + +#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 PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \ + SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname) + +#define TESTSCFLAG_FALSE(uname) \ + TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname) + +__PAGEFLAG(Locked, locked, PF_NO_TAIL) +PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) __CLEARPAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) +PAGEFLAG(Error, error, PF_NO_TAIL) TESTCLEARFLAG(Error, error, PF_NO_TAIL) +PAGEFLAG(Referenced, referenced, PF_HEAD) + TESTCLEARFLAG(Referenced, referenced, PF_HEAD) + __SETPAGEFLAG(Referenced, referenced, PF_HEAD) +PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD) + __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD) +PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD) +PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD) + TESTCLEARFLAG(Active, active, PF_HEAD) +__PAGEFLAG(Slab, slab, PF_NO_TAIL) +__PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL) +PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */ + +/* Xen */ +PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND) + TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND) +PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND); +PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND); + +PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) + __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) +PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) + __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) + __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) + +/* + * 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, PF_ANY) __SETPAGEFLAG(Private, private, PF_ANY) + __CLEARPAGEFLAG(Private, private, PF_ANY) +PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY) +PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY) + TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY) + +/* + * Only test-and-set exist for PG_writeback. The unconditional operators are + * risky: they bypass page accounting. + */ +TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL) + TESTSCFLAG(Writeback, writeback, PF_NO_TAIL) +PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL) + +/* PG_readahead is only used for reads; PG_reclaim is only for writes */ +PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL) + TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL) +PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND) + TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND) + +#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_idx(page_zonenum(__p)) +#else +PAGEFLAG_FALSE(HighMem) +#endif + +#ifdef CONFIG_SWAP +static __always_inline int PageSwapCache(struct page *page) +{ +#ifdef CONFIG_THP_SWAP + page = compound_head(page); +#endif + return PageSwapBacked(page) && test_bit(PG_swapcache, &page->flags); + +} +SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL) +CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL) +#else +PAGEFLAG_FALSE(SwapCache) +#endif + +PAGEFLAG(Unevictable, unevictable, PF_HEAD) + __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD) + TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD) + +#ifdef CONFIG_MMU +PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL) + __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL) + TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL) +#else +PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked) + TESTSCFLAG_FALSE(Mlocked) +#endif + +#ifdef CONFIG_ARCH_USES_PG_UNCACHED +PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND) +#else +PAGEFLAG_FALSE(Uncached) +#endif + +#ifdef CONFIG_MEMORY_FAILURE +PAGEFLAG(HWPoison, hwpoison, PF_ANY) +TESTSCFLAG(HWPoison, hwpoison, PF_ANY) +#define __PG_HWPOISON (1UL << PG_hwpoison) +extern bool set_hwpoison_free_buddy_page(struct page *page); +#else +PAGEFLAG_FALSE(HWPoison) +static inline bool set_hwpoison_free_buddy_page(struct page *page) +{ + return 0; +} +#define __PG_HWPOISON 0 +#endif + +#if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT) +TESTPAGEFLAG(Young, young, PF_ANY) +SETPAGEFLAG(Young, young, PF_ANY) +TESTCLEARFLAG(Young, young, PF_ANY) +PAGEFLAG(Idle, idle, PF_ANY) +#endif + +/* + * On an anonymous page mapped into a user virtual memory area, + * page->mapping points to its anon_vma, not to a struct address_space; + * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h. + * + * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled, + * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON + * bit; and then page->mapping points, not to an anon_vma, but to a private + * structure which KSM associates with that merged page. See ksm.h. + * + * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable + * page and then page->mapping points a struct address_space. + * + * Please note that, confusingly, "page_mapping" refers to the inode + * address_space which maps the page from disk; whereas "page_mapped" + * refers to user virtual address space into which the page is mapped. + */ +#define PAGE_MAPPING_ANON 0x1 +#define PAGE_MAPPING_MOVABLE 0x2 +#define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE) +#define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE) + +static __always_inline int PageMappingFlags(struct page *page) +{ + return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0; +} + +static __always_inline int PageAnon(struct page *page) +{ + page = compound_head(page); + return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0; +} + +static __always_inline int __PageMovable(struct page *page) +{ + return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == + PAGE_MAPPING_MOVABLE; +} + +#ifdef CONFIG_KSM +/* + * A KSM page is one of those write-protected "shared pages" or "merged pages" + * which KSM maps into multiple mms, wherever identical anonymous page content + * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any + * anon_vma, but to that page's node of the stable tree. + */ +static __always_inline int PageKsm(struct page *page) +{ + page = compound_head(page); + return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == + PAGE_MAPPING_KSM; +} +#else +TESTPAGEFLAG_FALSE(Ksm) +#endif + +u64 stable_page_flags(struct page *page); + +static inline int PageUptodate(struct page *page) +{ + int ret; + page = compound_head(page); + 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 __always_inline void __SetPageUptodate(struct page *page) +{ + VM_BUG_ON_PAGE(PageTail(page), page); + smp_wmb(); + __set_bit(PG_uptodate, &page->flags); +} + +static __always_inline void SetPageUptodate(struct page *page) +{ + VM_BUG_ON_PAGE(PageTail(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, PF_NO_TAIL) + +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); +} + +__PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY) + +static __always_inline void set_compound_head(struct page *page, struct page *head) +{ + WRITE_ONCE(page->compound_head, (unsigned long)head + 1); +} + +static __always_inline void clear_compound_head(struct page *page) +{ + WRITE_ONCE(page->compound_head, 0); +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +static inline void ClearPageCompound(struct page *page) +{ + BUG_ON(!PageHead(page)); + ClearPageHead(page); +} +#endif + +#define PG_head_mask ((1UL << PG_head)) + +#ifdef CONFIG_HUGETLB_PAGE +int PageHuge(struct page *page); +int PageHeadHuge(struct page *page); +bool page_huge_active(struct page *page); +#else +TESTPAGEFLAG_FALSE(Huge) +TESTPAGEFLAG_FALSE(HeadHuge) + +static inline bool page_huge_active(struct page *page) +{ + return 0; +} +#endif + + +#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); +} + +/* + * PageTransCompoundMap is the same as PageTransCompound, but it also + * guarantees the primary MMU has the entire compound page mapped + * through pmd_trans_huge, which in turn guarantees the secondary MMUs + * can also map the entire compound page. This allows the secondary + * MMUs to call get_user_pages() only once for each compound page and + * to immediately map the entire compound page with a single secondary + * MMU fault. If there will be a pmd split later, the secondary MMUs + * will get an update through the MMU notifier invalidation through + * split_huge_pmd(). + * + * Unlike PageTransCompound, this is safe to be called only while + * split_huge_pmd() cannot run from under us, like if protected by the + * MMU notifier, otherwise it may result in page->_mapcount check false + * positives. + * + * We have to treat page cache THP differently since every subpage of it + * would get _mapcount inc'ed once it is PMD mapped. But, it may be PTE + * mapped in the current process so comparing subpage's _mapcount to + * compound_mapcount to filter out PTE mapped case. + */ +static inline int PageTransCompoundMap(struct page *page) +{ + struct page *head; + + if (!PageTransCompound(page)) + return 0; + + if (PageAnon(page)) + return atomic_read(&page->_mapcount) < 0; + + head = compound_head(page); + /* File THP is PMD mapped and not PTE mapped */ + return atomic_read(&page->_mapcount) == + atomic_read(compound_mapcount_ptr(head)); +} + +/* + * 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); +} + +/* + * PageDoubleMap indicates that the compound page is mapped with PTEs as well + * as PMDs. + * + * This is required for optimization of rmap operations for THP: we can postpone + * per small page mapcount accounting (and its overhead from atomic operations) + * until the first PMD split. + * + * For the page PageDoubleMap means ->_mapcount in all sub-pages is offset up + * by one. This reference will go away with last compound_mapcount. + * + * See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap(). + */ +static inline int PageDoubleMap(struct page *page) +{ + return PageHead(page) && test_bit(PG_double_map, &page[1].flags); +} + +static inline void SetPageDoubleMap(struct page *page) +{ + VM_BUG_ON_PAGE(!PageHead(page), page); + set_bit(PG_double_map, &page[1].flags); +} + +static inline void ClearPageDoubleMap(struct page *page) +{ + VM_BUG_ON_PAGE(!PageHead(page), page); + clear_bit(PG_double_map, &page[1].flags); +} +static inline int TestSetPageDoubleMap(struct page *page) +{ + VM_BUG_ON_PAGE(!PageHead(page), page); + return test_and_set_bit(PG_double_map, &page[1].flags); +} + +static inline int TestClearPageDoubleMap(struct page *page) +{ + VM_BUG_ON_PAGE(!PageHead(page), page); + return test_and_clear_bit(PG_double_map, &page[1].flags); +} + +#else +TESTPAGEFLAG_FALSE(TransHuge) +TESTPAGEFLAG_FALSE(TransCompound) +TESTPAGEFLAG_FALSE(TransCompoundMap) +TESTPAGEFLAG_FALSE(TransTail) +PAGEFLAG_FALSE(DoubleMap) + TESTSETFLAG_FALSE(DoubleMap) + TESTCLEARFLAG_FALSE(DoubleMap) +#endif + +/* + * For pages that are never mapped to userspace (and aren't PageSlab), + * page_type may be used. Because it is initialised to -1, we invert the + * sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and + * __ClearPageFoo *sets* the bit used for PageFoo. We reserve a few high and + * low bits so that an underflow or overflow of page_mapcount() won't be + * mistaken for a page type value. + */ + +#define PAGE_TYPE_BASE 0xf0000000 +/* Reserve 0x0000007f to catch underflows of page_mapcount */ +#define PG_buddy 0x00000080 +#define PG_balloon 0x00000100 +#define PG_kmemcg 0x00000200 +#define PG_table 0x00000400 + +#define PageType(page, flag) \ + ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE) + +#define PAGE_TYPE_OPS(uname, lname) \ +static __always_inline int Page##uname(struct page *page) \ +{ \ + return PageType(page, PG_##lname); \ +} \ +static __always_inline void __SetPage##uname(struct page *page) \ +{ \ + VM_BUG_ON_PAGE(!PageType(page, 0), page); \ + page->page_type &= ~PG_##lname; \ +} \ +static __always_inline void __ClearPage##uname(struct page *page) \ +{ \ + VM_BUG_ON_PAGE(!Page##uname(page), page); \ + page->page_type |= PG_##lname; \ +} + +/* + * PageBuddy() indicates that the page is free and in the buddy system + * (see mm/page_alloc.c). + */ +PAGE_TYPE_OPS(Buddy, buddy) + +/* + * PageBalloon() is true for pages that are on the balloon page list + * (see mm/balloon_compaction.c). + */ +PAGE_TYPE_OPS(Balloon, balloon) + +/* + * If kmemcg is enabled, the buddy allocator will set PageKmemcg() on + * pages allocated with __GFP_ACCOUNT. It gets cleared on page free. + */ +PAGE_TYPE_OPS(Kmemcg, kmemcg) + +/* + * Marks pages in use as page tables. + */ +PAGE_TYPE_OPS(Table, table) + +extern bool is_free_buddy_page(struct page *page); + +__PAGEFLAG(Isolated, isolated, PF_ANY); + +/* + * 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 (1UL << 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 \ + (1UL << PG_lru | 1UL << PG_locked | \ + 1UL << PG_private | 1UL << PG_private_2 | \ + 1UL << PG_writeback | 1UL << PG_reserved | \ + 1UL << PG_slab | 1UL << PG_active | \ + 1UL << PG_unevictable | __PG_MLOCKED) + +/* + * Flags checked when a page is prepped for return by the page allocator. + * Pages being prepped should not have these flags set. It they are set, + * there has been a kernel bug or struct page corruption. + * + * __PG_HWPOISON is exceptional because it needs to be kept beyond page's + * alloc-free cycle to prevent from reusing the page. + */ +#define PAGE_FLAGS_CHECK_AT_PREP \ + (((1UL << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON) + +#define PAGE_FLAGS_PRIVATE \ + (1UL << PG_private | 1UL << 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); +} + +#undef PF_ANY +#undef PF_HEAD +#undef PF_ONLY_HEAD +#undef PF_NO_TAIL +#undef PF_NO_COMPOUND +#endif /* !__GENERATING_BOUNDS_H */ + +#endif /* PAGE_FLAGS_H */ |