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Diffstat (limited to 'include/linux/page-flags.h')
| -rw-r--r-- | include/linux/page-flags.h | 1107 |
1 files changed, 1107 insertions, 0 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h new file mode 100644 index 000000000..59314d228 --- /dev/null +++ b/include/linux/page-flags.h @@ -0,0 +1,1107 @@ +/* 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. The "struct page" of such a page + * should in general not be touched (e.g. set dirty) except by its owner. + * Pages marked as PG_reserved include: + * - Pages part of the kernel image (including vDSO) and similar (e.g. BIOS, + * initrd, HW tables) + * - Pages reserved or allocated early during boot (before the page allocator + * was initialized). This includes (depending on the architecture) the + * initial vmemmap, initial page tables, crashkernel, elfcorehdr, and much + * much more. Once (if ever) freed, PG_reserved is cleared and they will + * be given to the page allocator. + * - Pages falling into physical memory gaps - not IORESOURCE_SYSRAM. Trying + * to read/write these pages might end badly. Don't touch! + * - The zero page(s) + * - Pages not added to the page allocator when onlining a section because + * they were excluded via the online_page_callback() or because they are + * PG_hwpoison. + * - Pages allocated in the context of kexec/kdump (loaded kernel image, + * control pages, vmcoreinfo) + * - MMIO/DMA pages. Some architectures don't allow to ioremap pages that are + * not marked PG_reserved (as they might be in use by somebody else who does + * not respect the caching strategy). + * - Pages part of an offline section (struct pages of offline sections should + * not be trusted as they will be initialized when first onlined). + * - MCA pages on ia64 + * - Pages holding CPU notes for POWER Firmware Assisted Dump + * - Device memory (e.g. PMEM, DAX, HMM) + * Some PG_reserved pages will be excluded from the hibernation image. + * PG_reserved does in general not hinder anybody from dumping or swapping + * and is no longer required for remap_pfn_range(). ioremap might require it. + * Consequently, PG_reserved for a page mapped into user space can indicate + * the zero page, the vDSO, MMIO pages or device memory. + * + * 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_swapbacked is set when a page uses swap as a backing storage. This are + * usually PageAnon or shmem pages but please note that even anonymous pages + * might lose their PG_swapbacked flag when they simply can be dropped (e.g. as + * a result of MADV_FREE). + * + * 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 pageflags directly. Use the PageFoo macros. + * + * 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_referenced, + PG_uptodate, + PG_dirty, + PG_lru, + PG_active, + PG_workingset, + PG_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */ + PG_error, + 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_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT) + PG_young, + PG_idle, +#endif +#ifdef CONFIG_64BIT + PG_arch_2, +#endif +#ifdef CONFIG_KASAN_HW_TAGS + PG_skip_kasan_poison, +#endif + __NR_PAGEFLAGS, + + PG_readahead = PG_reclaim, + + /* + * Depending on the way an anonymous folio can be mapped into a page + * table (e.g., single PMD/PUD/CONT of the head page vs. PTE-mapped + * THP), PG_anon_exclusive may be set only for the head page or for + * tail pages of an anonymous folio. For now, we only expect it to be + * set on tail pages for PTE-mapped THP. + */ + PG_anon_exclusive = PG_mappedtodisk, + + /* 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, + /* Remapped by swiotlb-xen. */ + PG_xen_remapped = PG_owner_priv_1, + + /* SLOB */ + PG_slob_free = PG_private, + + /* Compound pages. Stored in first tail page's flags */ + PG_double_map = PG_workingset, + +#ifdef CONFIG_MEMORY_FAILURE + /* + * Compound pages. Stored in first tail page's flags. + * Indicates that at least one subpage is hwpoisoned in the + * THP. + */ + PG_has_hwpoisoned = PG_error, +#endif + + /* non-lru isolated movable page */ + PG_isolated = PG_reclaim, + + /* Only valid for buddy pages. Used to track pages that are reported */ + PG_reported = PG_uptodate, + +#ifdef CONFIG_MEMORY_HOTPLUG + /* For self-hosted memmap pages */ + PG_vmemmap_self_hosted = PG_owner_priv_1, +#endif +}; + +#define PAGEFLAGS_MASK ((1UL << NR_PAGEFLAGS) - 1) + +#ifndef __GENERATING_BOUNDS_H + +#ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP +DECLARE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key); + +/* + * Return the real head page struct iff the @page is a fake head page, otherwise + * return the @page itself. See Documentation/mm/vmemmap_dedup.rst. + */ +static __always_inline const struct page *page_fixed_fake_head(const struct page *page) +{ + if (!static_branch_unlikely(&hugetlb_optimize_vmemmap_key)) + return page; + + /* + * Only addresses aligned with PAGE_SIZE of struct page may be fake head + * struct page. The alignment check aims to avoid access the fields ( + * e.g. compound_head) of the @page[1]. It can avoid touch a (possibly) + * cold cacheline in some cases. + */ + if (IS_ALIGNED((unsigned long)page, PAGE_SIZE) && + test_bit(PG_head, &page->flags)) { + /* + * We can safely access the field of the @page[1] with PG_head + * because the @page is a compound page composed with at least + * two contiguous pages. + */ + unsigned long head = READ_ONCE(page[1].compound_head); + + if (likely(head & 1)) + return (const struct page *)(head - 1); + } + return page; +} +#else +static inline const struct page *page_fixed_fake_head(const struct page *page) +{ + return page; +} +#endif + +static __always_inline int page_is_fake_head(struct page *page) +{ + return page_fixed_fake_head(page) != page; +} + +static inline unsigned long _compound_head(const struct page *page) +{ + unsigned long head = READ_ONCE(page->compound_head); + + if (unlikely(head & 1)) + return head - 1; + return (unsigned long)page_fixed_fake_head(page); +} + +#define compound_head(page) ((typeof(page))_compound_head(page)) + +/** + * page_folio - Converts from page to folio. + * @p: The page. + * + * Every page is part of a folio. This function cannot be called on a + * NULL pointer. + * + * Context: No reference, nor lock is required on @page. If the caller + * does not hold a reference, this call may race with a folio split, so + * it should re-check the folio still contains this page after gaining + * a reference on the folio. + * Return: The folio which contains this page. + */ +#define page_folio(p) (_Generic((p), \ + const struct page *: (const struct folio *)_compound_head(p), \ + struct page *: (struct folio *)_compound_head(p))) + +/** + * folio_page - Return a page from a folio. + * @folio: The folio. + * @n: The page number to return. + * + * @n is relative to the start of the folio. This function does not + * check that the page number lies within @folio; the caller is presumed + * to have a reference to the page. + */ +#define folio_page(folio, n) nth_page(&(folio)->page, n) + +static __always_inline int PageTail(struct page *page) +{ + return READ_ONCE(page->compound_head) & 1 || page_is_fake_head(page); +} + +static __always_inline int PageCompound(struct page *page) +{ + return test_bit(PG_head, &page->flags) || + READ_ONCE(page->compound_head) & 1; +} + +#define PAGE_POISON_PATTERN -1l +static inline int PagePoisoned(const struct page *page) +{ + return READ_ONCE(page->flags) == PAGE_POISON_PATTERN; +} + +#ifdef CONFIG_DEBUG_VM +void page_init_poison(struct page *page, size_t size); +#else +static inline void page_init_poison(struct page *page, size_t size) +{ +} +#endif + +static unsigned long *folio_flags(struct folio *folio, unsigned n) +{ + struct page *page = &folio->page; + + VM_BUG_ON_PGFLAGS(PageTail(page), page); + VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page); + return &page[n].flags; +} + +/* + * 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. + * + * PF_SECOND: + * the page flag is stored in the first tail page. + */ +#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); }) +#define PF_SECOND(page, enforce) ({ \ + VM_BUG_ON_PGFLAGS(!PageHead(page), page); \ + PF_POISONED_CHECK(&page[1]); }) + +/* Which page is the flag stored in */ +#define FOLIO_PF_ANY 0 +#define FOLIO_PF_HEAD 0 +#define FOLIO_PF_ONLY_HEAD 0 +#define FOLIO_PF_NO_TAIL 0 +#define FOLIO_PF_NO_COMPOUND 0 +#define FOLIO_PF_SECOND 1 + +/* + * Macros to create function definitions for page flags + */ +#define TESTPAGEFLAG(uname, lname, policy) \ +static __always_inline bool folio_test_##lname(struct folio *folio) \ +{ return test_bit(PG_##lname, folio_flags(folio, FOLIO_##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 folio_set_##lname(struct folio *folio) \ +{ set_bit(PG_##lname, folio_flags(folio, FOLIO_##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 folio_clear_##lname(struct folio *folio) \ +{ clear_bit(PG_##lname, folio_flags(folio, FOLIO_##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 __folio_set_##lname(struct folio *folio) \ +{ __set_bit(PG_##lname, folio_flags(folio, FOLIO_##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 __folio_clear_##lname(struct folio *folio) \ +{ __clear_bit(PG_##lname, folio_flags(folio, FOLIO_##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 \ +bool folio_test_set_##lname(struct folio *folio) \ +{ return test_and_set_bit(PG_##lname, folio_flags(folio, FOLIO_##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 \ +bool folio_test_clear_##lname(struct folio *folio) \ +{ return test_and_clear_bit(PG_##lname, folio_flags(folio, FOLIO_##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, lname) \ +static inline bool folio_test_##lname(const struct folio *folio) { return false; } \ +static inline int Page##uname(const struct page *page) { return 0; } + +#define SETPAGEFLAG_NOOP(uname, lname) \ +static inline void folio_set_##lname(struct folio *folio) { } \ +static inline void SetPage##uname(struct page *page) { } + +#define CLEARPAGEFLAG_NOOP(uname, lname) \ +static inline void folio_clear_##lname(struct folio *folio) { } \ +static inline void ClearPage##uname(struct page *page) { } + +#define __CLEARPAGEFLAG_NOOP(uname, lname) \ +static inline void __folio_clear_##lname(struct folio *folio) { } \ +static inline void __ClearPage##uname(struct page *page) { } + +#define TESTSETFLAG_FALSE(uname, lname) \ +static inline bool folio_test_set_##lname(struct folio *folio) \ +{ return 0; } \ +static inline int TestSetPage##uname(struct page *page) { return 0; } + +#define TESTCLEARFLAG_FALSE(uname, lname) \ +static inline bool folio_test_clear_##lname(struct folio *folio) \ +{ return 0; } \ +static inline int TestClearPage##uname(struct page *page) { return 0; } + +#define PAGEFLAG_FALSE(uname, lname) TESTPAGEFLAG_FALSE(uname, lname) \ + SETPAGEFLAG_NOOP(uname, lname) CLEARPAGEFLAG_NOOP(uname, lname) + +#define TESTSCFLAG_FALSE(uname, lname) \ + TESTSETFLAG_FALSE(uname, lname) TESTCLEARFLAG_FALSE(uname, lname) + +__PAGEFLAG(Locked, locked, PF_NO_TAIL) +PAGEFLAG(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) + TESTCLEARFLAG(LRU, lru, PF_HEAD) +PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD) + TESTCLEARFLAG(Active, active, PF_HEAD) +PAGEFLAG(Workingset, workingset, PF_HEAD) + TESTCLEARFLAG(Workingset, workingset, 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(XenRemapped, xen_remapped, PF_NO_COMPOUND) + TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND) + +PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) + __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) + __SETPAGEFLAG(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 release_folio() and co to be invoked + */ +PAGEFLAG(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, readahead, PF_NO_COMPOUND) + TESTCLEARFLAG(Readahead, readahead, 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, highmem) +#endif + +#ifdef CONFIG_SWAP +static __always_inline bool folio_test_swapcache(struct folio *folio) +{ + return folio_test_swapbacked(folio) && + test_bit(PG_swapcache, folio_flags(folio, 0)); +} + +static __always_inline bool PageSwapCache(struct page *page) +{ + return folio_test_swapcache(page_folio(page)); +} + +SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL) +CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL) +#else +PAGEFLAG_FALSE(SwapCache, 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, mlocked) __CLEARPAGEFLAG_NOOP(Mlocked, mlocked) + TESTSCFLAG_FALSE(Mlocked, mlocked) +#endif + +#ifdef CONFIG_ARCH_USES_PG_UNCACHED +PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND) +#else +PAGEFLAG_FALSE(Uncached, uncached) +#endif + +#ifdef CONFIG_MEMORY_FAILURE +PAGEFLAG(HWPoison, hwpoison, PF_ANY) +TESTSCFLAG(HWPoison, hwpoison, PF_ANY) +#define __PG_HWPOISON (1UL << PG_hwpoison) +#define MAGIC_HWPOISON 0x48575053U /* HWPS */ +extern void SetPageHWPoisonTakenOff(struct page *page); +extern void ClearPageHWPoisonTakenOff(struct page *page); +extern bool take_page_off_buddy(struct page *page); +extern bool put_page_back_buddy(struct page *page); +#else +PAGEFLAG_FALSE(HWPoison, hwpoison) +#define __PG_HWPOISON 0 +#endif + +#if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT) +TESTPAGEFLAG(Young, young, PF_ANY) +SETPAGEFLAG(Young, young, PF_ANY) +TESTCLEARFLAG(Young, young, PF_ANY) +PAGEFLAG(Idle, idle, PF_ANY) +#endif + +#ifdef CONFIG_KASAN_HW_TAGS +PAGEFLAG(SkipKASanPoison, skip_kasan_poison, PF_HEAD) +#else +PAGEFLAG_FALSE(SkipKASanPoison, skip_kasan_poison) +#endif + +/* + * PageReported() is used to track reported free pages within the Buddy + * allocator. We can use the non-atomic version of the test and set + * operations as both should be shielded with the zone lock to prevent + * any possible races on the setting or clearing of the bit. + */ +__PAGEFLAG(Reported, reported, PF_NO_COMPOUND) + +#ifdef CONFIG_MEMORY_HOTPLUG +PAGEFLAG(VmemmapSelfHosted, vmemmap_self_hosted, PF_ANY) +#else +PAGEFLAG_FALSE(VmemmapSelfHosted, vmemmap_self_hosted) +#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 to a struct movable_operations. + * + * 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. + * + * For slab pages, since slab reuses the bits in struct page to store its + * internal states, the page->mapping does not exist as such, nor do these + * flags below. So in order to avoid testing non-existent bits, please + * make sure that PageSlab(page) actually evaluates to false before calling + * the following functions (e.g., PageAnon). See mm/slab.h. + */ +#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) + +/* + * Different with flags above, this flag is used only for fsdax mode. It + * indicates that this page->mapping is now under reflink case. + */ +#define PAGE_MAPPING_DAX_COW 0x1 + +static __always_inline bool folio_mapping_flags(struct folio *folio) +{ + return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) != 0; +} + +static __always_inline int PageMappingFlags(struct page *page) +{ + return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0; +} + +static __always_inline bool folio_test_anon(struct folio *folio) +{ + return ((unsigned long)folio->mapping & PAGE_MAPPING_ANON) != 0; +} + +static __always_inline bool PageAnon(struct page *page) +{ + return folio_test_anon(page_folio(page)); +} + +static __always_inline bool __folio_test_movable(const struct folio *folio) +{ + return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) == + PAGE_MAPPING_MOVABLE; +} + +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 bool folio_test_ksm(struct folio *folio) +{ + return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) == + PAGE_MAPPING_KSM; +} + +static __always_inline bool PageKsm(struct page *page) +{ + return folio_test_ksm(page_folio(page)); +} +#else +TESTPAGEFLAG_FALSE(Ksm, ksm) +#endif + +u64 stable_page_flags(struct page *page); + +/** + * folio_test_uptodate - Is this folio up to date? + * @folio: The folio. + * + * The uptodate flag is set on a folio when every byte in the folio is + * at least as new as the corresponding bytes on storage. Anonymous + * and CoW folios are always uptodate. If the folio is not uptodate, + * some of the bytes in it may be; see the is_partially_uptodate() + * address_space operation. + */ +static inline bool folio_test_uptodate(struct folio *folio) +{ + bool ret = test_bit(PG_uptodate, folio_flags(folio, 0)); + /* + * Must ensure that the data we read out of the folio is loaded + * _after_ we've loaded folio->flags to check the uptodate bit. + * We can skip the barrier if the folio is not uptodate, because + * we wouldn't be reading anything from it. + * + * See folio_mark_uptodate() for the other side of the story. + */ + if (ret) + smp_rmb(); + + return ret; +} + +static inline int PageUptodate(struct page *page) +{ + return folio_test_uptodate(page_folio(page)); +} + +static __always_inline void __folio_mark_uptodate(struct folio *folio) +{ + smp_wmb(); + __set_bit(PG_uptodate, folio_flags(folio, 0)); +} + +static __always_inline void folio_mark_uptodate(struct folio *folio) +{ + /* + * Memory barrier must be issued before setting the PG_uptodate bit, + * so that all previous stores issued in order to bring the folio + * uptodate are actually visible before folio_test_uptodate becomes true. + */ + smp_wmb(); + set_bit(PG_uptodate, folio_flags(folio, 0)); +} + +static __always_inline void __SetPageUptodate(struct page *page) +{ + __folio_mark_uptodate((struct folio *)page); +} + +static __always_inline void SetPageUptodate(struct page *page) +{ + folio_mark_uptodate((struct folio *)page); +} + +CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL) + +bool __folio_start_writeback(struct folio *folio, bool keep_write); +bool set_page_writeback(struct page *page); + +#define folio_start_writeback(folio) \ + __folio_start_writeback(folio, false) +#define folio_start_writeback_keepwrite(folio) \ + __folio_start_writeback(folio, true) + +static inline void set_page_writeback_keepwrite(struct page *page) +{ + folio_start_writeback_keepwrite(page_folio(page)); +} + +static inline bool test_set_page_writeback(struct page *page) +{ + return set_page_writeback(page); +} + +static __always_inline bool folio_test_head(struct folio *folio) +{ + return test_bit(PG_head, folio_flags(folio, FOLIO_PF_ANY)); +} + +static __always_inline int PageHead(struct page *page) +{ + PF_POISONED_CHECK(page); + return test_bit(PG_head, &page->flags) && !page_is_fake_head(page); +} + +__SETPAGEFLAG(Head, head, PF_ANY) +__CLEARPAGEFLAG(Head, head, PF_ANY) +CLEARPAGEFLAG(Head, head, PF_ANY) + +/** + * folio_test_large() - Does this folio contain more than one page? + * @folio: The folio to test. + * + * Return: True if the folio is larger than one page. + */ +static inline bool folio_test_large(struct folio *folio) +{ + return folio_test_head(folio); +} + +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); +static inline bool folio_test_hugetlb(struct folio *folio) +{ + return PageHeadHuge(&folio->page); +} +#else +TESTPAGEFLAG_FALSE(Huge, hugetlb) +TESTPAGEFLAG_FALSE(HeadHuge, headhuge) +#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); +} + +static inline bool folio_test_transhuge(struct folio *folio) +{ + return folio_test_head(folio); +} + +/* + * 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); +} + +/* + * 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(). + */ +PAGEFLAG(DoubleMap, double_map, PF_SECOND) + TESTSCFLAG(DoubleMap, double_map, PF_SECOND) +#else +TESTPAGEFLAG_FALSE(TransHuge, transhuge) +TESTPAGEFLAG_FALSE(TransCompound, transcompound) +TESTPAGEFLAG_FALSE(TransCompoundMap, transcompoundmap) +TESTPAGEFLAG_FALSE(TransTail, transtail) +PAGEFLAG_FALSE(DoubleMap, double_map) + TESTSCFLAG_FALSE(DoubleMap, double_map) +#endif + +#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_TRANSPARENT_HUGEPAGE) +/* + * PageHasHWPoisoned indicates that at least one subpage is hwpoisoned in the + * compound page. + * + * This flag is set by hwpoison handler. Cleared by THP split or free page. + */ +PAGEFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND) + TESTSCFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND) +#else +PAGEFLAG_FALSE(HasHWPoisoned, has_hwpoisoned) + TESTSCFLAG_FALSE(HasHWPoisoned, has_hwpoisoned) +#endif + +/* + * Check if a page is currently marked HWPoisoned. Note that this check is + * best effort only and inherently racy: there is no way to synchronize with + * failing hardware. + */ +static inline bool is_page_hwpoison(struct page *page) +{ + if (PageHWPoison(page)) + return true; + return PageHuge(page) && PageHWPoison(compound_head(page)); +} + +/* + * 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 PAGE_MAPCOUNT_RESERVE -128 +#define PG_buddy 0x00000080 +#define PG_offline 0x00000100 +#define PG_table 0x00000200 +#define PG_guard 0x00000400 + +#define PageType(page, flag) \ + ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE) + +static inline int page_has_type(struct page *page) +{ + return (int)page->page_type < PAGE_MAPCOUNT_RESERVE; +} + +#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) + +/* + * PageOffline() indicates that the page is logically offline although the + * containing section is online. (e.g. inflated in a balloon driver or + * not onlined when onlining the section). + * The content of these pages is effectively stale. Such pages should not + * be touched (read/write/dump/save) except by their owner. + * + * If a driver wants to allow to offline unmovable PageOffline() pages without + * putting them back to the buddy, it can do so via the memory notifier by + * decrementing the reference count in MEM_GOING_OFFLINE and incrementing the + * reference count in MEM_CANCEL_OFFLINE. When offlining, the PageOffline() + * pages (now with a reference count of zero) are treated like free pages, + * allowing the containing memory block to get offlined. A driver that + * relies on this feature is aware that re-onlining the memory block will + * require to re-set the pages PageOffline() and not giving them to the + * buddy via online_page_callback_t. + * + * There are drivers that mark a page PageOffline() and expect there won't be + * any further access to page content. PFN walkers that read content of random + * pages should check PageOffline() and synchronize with such drivers using + * page_offline_freeze()/page_offline_thaw(). + */ +PAGE_TYPE_OPS(Offline, offline) + +extern void page_offline_freeze(void); +extern void page_offline_thaw(void); +extern void page_offline_begin(void); +extern void page_offline_end(void); + +/* + * Marks pages in use as page tables. + */ +PAGE_TYPE_OPS(Table, table) + +/* + * Marks guardpages used with debug_pagealloc. + */ +PAGE_TYPE_OPS(Guard, guard) + +extern bool is_free_buddy_page(struct page *page); + +PAGEFLAG(Isolated, isolated, PF_ANY); + +static __always_inline int PageAnonExclusive(struct page *page) +{ + VM_BUG_ON_PGFLAGS(!PageAnon(page), page); + VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); + return test_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags); +} + +static __always_inline void SetPageAnonExclusive(struct page *page) +{ + VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page); + VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); + set_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags); +} + +static __always_inline void ClearPageAnonExclusive(struct page *page) +{ + VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page); + VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); + clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags); +} + +static __always_inline void __ClearPageAnonExclusive(struct page *page) +{ + VM_BUG_ON_PGFLAGS(!PageAnon(page), page); + VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); + __clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags); +} + +#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. If 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 | LRU_GEN_MASK) + +/* + * Flags checked when a page is prepped for return by the page allocator. + * Pages being prepped should not have these flags set. If 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 \ + ((PAGEFLAGS_MASK & ~__PG_HWPOISON) | LRU_GEN_MASK | LRU_REFS_MASK) + +#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); +} + +static inline bool folio_has_private(struct folio *folio) +{ + return page_has_private(&folio->page); +} + +#undef PF_ANY +#undef PF_HEAD +#undef PF_ONLY_HEAD +#undef PF_NO_TAIL +#undef PF_NO_COMPOUND +#undef PF_SECOND +#endif /* !__GENERATING_BOUNDS_H */ + +#endif /* PAGE_FLAGS_H */ |