1005 lines
32 KiB
C
1005 lines
32 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Macros for manipulating and testing page->flags
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*/
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#ifndef PAGE_FLAGS_H
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#define PAGE_FLAGS_H
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#include <linux/types.h>
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#include <linux/bug.h>
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#include <linux/mmdebug.h>
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#ifndef __GENERATING_BOUNDS_H
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#include <linux/mm_types.h>
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#include <generated/bounds.h>
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#endif /* !__GENERATING_BOUNDS_H */
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/*
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* Various page->flags bits:
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*
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* PG_reserved is set for special pages. The "struct page" of such a page
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* should in general not be touched (e.g. set dirty) except by its owner.
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* Pages marked as PG_reserved include:
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* - Pages part of the kernel image (including vDSO) and similar (e.g. BIOS,
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* initrd, HW tables)
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* - Pages reserved or allocated early during boot (before the page allocator
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* was initialized). This includes (depending on the architecture) the
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* initial vmemmap, initial page tables, crashkernel, elfcorehdr, and much
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* much more. Once (if ever) freed, PG_reserved is cleared and they will
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* be given to the page allocator.
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* - Pages falling into physical memory gaps - not IORESOURCE_SYSRAM. Trying
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* to read/write these pages might end badly. Don't touch!
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* - The zero page(s)
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* - Pages not added to the page allocator when onlining a section because
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* they were excluded via the online_page_callback() or because they are
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* PG_hwpoison.
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* - Pages allocated in the context of kexec/kdump (loaded kernel image,
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* control pages, vmcoreinfo)
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* - MMIO/DMA pages. Some architectures don't allow to ioremap pages that are
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* not marked PG_reserved (as they might be in use by somebody else who does
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* not respect the caching strategy).
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* - Pages part of an offline section (struct pages of offline sections should
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* not be trusted as they will be initialized when first onlined).
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* - MCA pages on ia64
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* - Pages holding CPU notes for POWER Firmware Assisted Dump
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* - Device memory (e.g. PMEM, DAX, HMM)
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* Some PG_reserved pages will be excluded from the hibernation image.
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* PG_reserved does in general not hinder anybody from dumping or swapping
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* and is no longer required for remap_pfn_range(). ioremap might require it.
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* Consequently, PG_reserved for a page mapped into user space can indicate
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* the zero page, the vDSO, MMIO pages or device memory.
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*
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* The PG_private bitflag is set on pagecache pages if they contain filesystem
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* specific data (which is normally at page->private). It can be used by
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* private allocations for its own usage.
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*
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* During initiation of disk I/O, PG_locked is set. This bit is set before I/O
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* and cleared when writeback _starts_ or when read _completes_. PG_writeback
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* is set before writeback starts and cleared when it finishes.
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*
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* PG_locked also pins a page in pagecache, and blocks truncation of the file
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* while it is held.
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*
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* page_waitqueue(page) is a wait queue of all tasks waiting for the page
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* to become unlocked.
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*
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* PG_swapbacked is set when a page uses swap as a backing storage. This are
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* usually PageAnon or shmem pages but please note that even anonymous pages
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* might lose their PG_swapbacked flag when they simply can be dropped (e.g. as
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* a result of MADV_FREE).
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*
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* PG_uptodate tells whether the page's contents is valid. When a read
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* completes, the page becomes uptodate, unless a disk I/O error happened.
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*
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* PG_referenced, PG_reclaim are used for page reclaim for anonymous and
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* file-backed pagecache (see mm/vmscan.c).
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*
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* PG_error is set to indicate that an I/O error occurred on this page.
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*
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* PG_arch_1 is an architecture specific page state bit. The generic code
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* guarantees that this bit is cleared for a page when it first is entered into
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* the page cache.
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*
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* PG_hwpoison indicates that a page got corrupted in hardware and contains
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* data with incorrect ECC bits that triggered a machine check. Accessing is
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* not safe since it may cause another machine check. Don't touch!
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*/
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/*
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* Don't use the pageflags directly. Use the PageFoo macros.
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*
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* The page flags field is split into two parts, the main flags area
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* which extends from the low bits upwards, and the fields area which
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* extends from the high bits downwards.
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*
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* | FIELD | ... | FLAGS |
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* N-1 ^ 0
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* (NR_PAGEFLAGS)
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*
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* The fields area is reserved for fields mapping zone, node (for NUMA) and
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* SPARSEMEM section (for variants of SPARSEMEM that require section ids like
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* SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
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*/
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enum pageflags {
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PG_locked, /* Page is locked. Don't touch. */
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PG_referenced,
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PG_uptodate,
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PG_dirty,
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PG_lru,
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PG_active,
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PG_workingset,
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PG_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
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PG_error,
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PG_slab,
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PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
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PG_arch_1,
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PG_reserved,
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PG_private, /* If pagecache, has fs-private data */
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PG_private_2, /* If pagecache, has fs aux data */
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PG_writeback, /* Page is under writeback */
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PG_head, /* A head page */
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PG_mappedtodisk, /* Has blocks allocated on-disk */
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PG_reclaim, /* To be reclaimed asap */
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PG_swapbacked, /* Page is backed by RAM/swap */
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PG_unevictable, /* Page is "unevictable" */
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#ifdef CONFIG_MMU
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PG_mlocked, /* Page is vma mlocked */
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#endif
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#ifdef CONFIG_ARCH_USES_PG_UNCACHED
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PG_uncached, /* Page has been mapped as uncached */
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#endif
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#ifdef CONFIG_MEMORY_FAILURE
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PG_hwpoison, /* hardware poisoned page. Don't touch */
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#endif
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#if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT)
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PG_young,
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PG_idle,
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#endif
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#ifdef CONFIG_64BIT
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PG_arch_2,
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#endif
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#ifdef CONFIG_KASAN_HW_TAGS
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PG_skip_kasan_poison,
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#endif
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__NR_PAGEFLAGS,
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PG_readahead = PG_reclaim,
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/* Filesystems */
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PG_checked = PG_owner_priv_1,
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/* SwapBacked */
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PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */
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/* Two page bits are conscripted by FS-Cache to maintain local caching
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* state. These bits are set on pages belonging to the netfs's inodes
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* when those inodes are being locally cached.
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*/
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PG_fscache = PG_private_2, /* page backed by cache */
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/* XEN */
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/* Pinned in Xen as a read-only pagetable page. */
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PG_pinned = PG_owner_priv_1,
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/* Pinned as part of domain save (see xen_mm_pin_all()). */
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PG_savepinned = PG_dirty,
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/* Has a grant mapping of another (foreign) domain's page. */
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PG_foreign = PG_owner_priv_1,
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/* Remapped by swiotlb-xen. */
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PG_xen_remapped = PG_owner_priv_1,
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/* SLOB */
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PG_slob_free = PG_private,
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/* Compound pages. Stored in first tail page's flags */
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PG_double_map = PG_workingset,
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#ifdef CONFIG_MEMORY_FAILURE
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/*
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* Compound pages. Stored in first tail page's flags.
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* Indicates that at least one subpage is hwpoisoned in the
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* THP.
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*/
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PG_has_hwpoisoned = PG_mappedtodisk,
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#endif
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/* non-lru isolated movable page */
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PG_isolated = PG_reclaim,
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/* Only valid for buddy pages. Used to track pages that are reported */
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PG_reported = PG_uptodate,
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};
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#define PAGEFLAGS_MASK ((1UL << NR_PAGEFLAGS) - 1)
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#ifndef __GENERATING_BOUNDS_H
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static inline unsigned long _compound_head(const struct page *page)
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{
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unsigned long head = READ_ONCE(page->compound_head);
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if (unlikely(head & 1))
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return head - 1;
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return (unsigned long)page;
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}
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#define compound_head(page) ((typeof(page))_compound_head(page))
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/**
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* page_folio - Converts from page to folio.
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* @p: The page.
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*
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* Every page is part of a folio. This function cannot be called on a
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* NULL pointer.
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*
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* Context: No reference, nor lock is required on @page. If the caller
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* does not hold a reference, this call may race with a folio split, so
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* it should re-check the folio still contains this page after gaining
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* a reference on the folio.
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* Return: The folio which contains this page.
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*/
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#define page_folio(p) (_Generic((p), \
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const struct page *: (const struct folio *)_compound_head(p), \
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struct page *: (struct folio *)_compound_head(p)))
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/**
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* folio_page - Return a page from a folio.
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* @folio: The folio.
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* @n: The page number to return.
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*
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* @n is relative to the start of the folio. This function does not
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* check that the page number lies within @folio; the caller is presumed
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* to have a reference to the page.
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*/
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#define folio_page(folio, n) nth_page(&(folio)->page, n)
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static __always_inline int PageTail(struct page *page)
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{
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return READ_ONCE(page->compound_head) & 1;
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}
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static __always_inline int PageCompound(struct page *page)
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{
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return test_bit(PG_head, &page->flags) || PageTail(page);
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}
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#define PAGE_POISON_PATTERN -1l
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static inline int PagePoisoned(const struct page *page)
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{
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return READ_ONCE(page->flags) == PAGE_POISON_PATTERN;
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}
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#ifdef CONFIG_DEBUG_VM
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void page_init_poison(struct page *page, size_t size);
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#else
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static inline void page_init_poison(struct page *page, size_t size)
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{
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}
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#endif
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static unsigned long *folio_flags(struct folio *folio, unsigned n)
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{
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struct page *page = &folio->page;
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VM_BUG_ON_PGFLAGS(PageTail(page), page);
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VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page);
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return &page[n].flags;
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}
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/*
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* Page flags policies wrt compound pages
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*
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* PF_POISONED_CHECK
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* check if this struct page poisoned/uninitialized
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*
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* PF_ANY:
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* the page flag is relevant for small, head and tail pages.
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*
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* PF_HEAD:
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* for compound page all operations related to the page flag applied to
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* head page.
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*
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* PF_ONLY_HEAD:
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* for compound page, callers only ever operate on the head page.
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*
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* PF_NO_TAIL:
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* modifications of the page flag must be done on small or head pages,
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* checks can be done on tail pages too.
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*
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* PF_NO_COMPOUND:
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* the page flag is not relevant for compound pages.
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*
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* PF_SECOND:
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* the page flag is stored in the first tail page.
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*/
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#define PF_POISONED_CHECK(page) ({ \
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VM_BUG_ON_PGFLAGS(PagePoisoned(page), page); \
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page; })
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#define PF_ANY(page, enforce) PF_POISONED_CHECK(page)
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#define PF_HEAD(page, enforce) PF_POISONED_CHECK(compound_head(page))
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#define PF_ONLY_HEAD(page, enforce) ({ \
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VM_BUG_ON_PGFLAGS(PageTail(page), page); \
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PF_POISONED_CHECK(page); })
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#define PF_NO_TAIL(page, enforce) ({ \
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VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
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PF_POISONED_CHECK(compound_head(page)); })
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#define PF_NO_COMPOUND(page, enforce) ({ \
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VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
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PF_POISONED_CHECK(page); })
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#define PF_SECOND(page, enforce) ({ \
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VM_BUG_ON_PGFLAGS(!PageHead(page), page); \
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PF_POISONED_CHECK(&page[1]); })
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/* Which page is the flag stored in */
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#define FOLIO_PF_ANY 0
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#define FOLIO_PF_HEAD 0
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#define FOLIO_PF_ONLY_HEAD 0
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#define FOLIO_PF_NO_TAIL 0
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#define FOLIO_PF_NO_COMPOUND 0
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#define FOLIO_PF_SECOND 1
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/*
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* Macros to create function definitions for page flags
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*/
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#define TESTPAGEFLAG(uname, lname, policy) \
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static __always_inline bool folio_test_##lname(struct folio *folio) \
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{ return test_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
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static __always_inline int Page##uname(struct page *page) \
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{ return test_bit(PG_##lname, &policy(page, 0)->flags); }
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#define SETPAGEFLAG(uname, lname, policy) \
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static __always_inline \
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void folio_set_##lname(struct folio *folio) \
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{ set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
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static __always_inline void SetPage##uname(struct page *page) \
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{ set_bit(PG_##lname, &policy(page, 1)->flags); }
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#define CLEARPAGEFLAG(uname, lname, policy) \
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static __always_inline \
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void folio_clear_##lname(struct folio *folio) \
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{ clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
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static __always_inline void ClearPage##uname(struct page *page) \
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{ clear_bit(PG_##lname, &policy(page, 1)->flags); }
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#define __SETPAGEFLAG(uname, lname, policy) \
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static __always_inline \
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void __folio_set_##lname(struct folio *folio) \
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{ __set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
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static __always_inline void __SetPage##uname(struct page *page) \
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{ __set_bit(PG_##lname, &policy(page, 1)->flags); }
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#define __CLEARPAGEFLAG(uname, lname, policy) \
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static __always_inline \
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void __folio_clear_##lname(struct folio *folio) \
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{ __clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
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static __always_inline void __ClearPage##uname(struct page *page) \
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{ __clear_bit(PG_##lname, &policy(page, 1)->flags); }
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#define TESTSETFLAG(uname, lname, policy) \
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static __always_inline \
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bool folio_test_set_##lname(struct folio *folio) \
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{ return test_and_set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
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static __always_inline int TestSetPage##uname(struct page *page) \
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{ return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
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#define TESTCLEARFLAG(uname, lname, policy) \
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static __always_inline \
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bool folio_test_clear_##lname(struct folio *folio) \
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{ return test_and_clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
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static __always_inline int TestClearPage##uname(struct page *page) \
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{ return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
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#define PAGEFLAG(uname, lname, policy) \
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TESTPAGEFLAG(uname, lname, policy) \
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SETPAGEFLAG(uname, lname, policy) \
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CLEARPAGEFLAG(uname, lname, policy)
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#define __PAGEFLAG(uname, lname, policy) \
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TESTPAGEFLAG(uname, lname, policy) \
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__SETPAGEFLAG(uname, lname, policy) \
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__CLEARPAGEFLAG(uname, lname, policy)
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#define TESTSCFLAG(uname, lname, policy) \
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TESTSETFLAG(uname, lname, policy) \
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TESTCLEARFLAG(uname, lname, policy)
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#define TESTPAGEFLAG_FALSE(uname, lname) \
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static inline bool folio_test_##lname(const struct folio *folio) { return 0; } \
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static inline int Page##uname(const struct page *page) { return 0; }
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#define SETPAGEFLAG_NOOP(uname, lname) \
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static inline void folio_set_##lname(struct folio *folio) { } \
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static inline void SetPage##uname(struct page *page) { }
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#define CLEARPAGEFLAG_NOOP(uname, lname) \
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static inline void folio_clear_##lname(struct folio *folio) { } \
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static inline void ClearPage##uname(struct page *page) { }
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#define __CLEARPAGEFLAG_NOOP(uname, lname) \
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static inline void __folio_clear_##lname(struct folio *folio) { } \
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static inline void __ClearPage##uname(struct page *page) { }
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#define TESTSETFLAG_FALSE(uname, lname) \
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static inline bool folio_test_set_##lname(struct folio *folio) \
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{ return 0; } \
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static inline int TestSetPage##uname(struct page *page) { return 0; }
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#define TESTCLEARFLAG_FALSE(uname, lname) \
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static inline bool folio_test_clear_##lname(struct folio *folio) \
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{ return 0; } \
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static inline int TestClearPage##uname(struct page *page) { return 0; }
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#define PAGEFLAG_FALSE(uname, lname) TESTPAGEFLAG_FALSE(uname, lname) \
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SETPAGEFLAG_NOOP(uname, lname) CLEARPAGEFLAG_NOOP(uname, lname)
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#define TESTSCFLAG_FALSE(uname, lname) \
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TESTSETFLAG_FALSE(uname, lname) TESTCLEARFLAG_FALSE(uname, lname)
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__PAGEFLAG(Locked, locked, PF_NO_TAIL)
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PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) __CLEARPAGEFLAG(Waiters, waiters, PF_ONLY_HEAD)
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PAGEFLAG(Error, error, PF_NO_TAIL) TESTCLEARFLAG(Error, error, PF_NO_TAIL)
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PAGEFLAG(Referenced, referenced, PF_HEAD)
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TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
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__SETPAGEFLAG(Referenced, referenced, PF_HEAD)
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PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
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__CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
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PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
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TESTCLEARFLAG(LRU, lru, PF_HEAD)
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PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
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TESTCLEARFLAG(Active, active, PF_HEAD)
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PAGEFLAG(Workingset, workingset, PF_HEAD)
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TESTCLEARFLAG(Workingset, workingset, PF_HEAD)
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__PAGEFLAG(Slab, slab, PF_NO_TAIL)
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__PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
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PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */
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/* Xen */
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PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
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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 releasepage() 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)
|
|
extern bool take_page_off_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)
|
|
|
|
/*
|
|
* 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 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 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);
|
|
|
|
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);
|
|
}
|
|
|
|
__PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY)
|
|
|
|
/* Whether there are one or multiple pages in a folio */
|
|
static inline bool folio_test_single(struct folio *folio)
|
|
{
|
|
return !folio_test_head(folio);
|
|
}
|
|
|
|
static inline bool folio_test_multi(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);
|
|
|
|
/*
|
|
* 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)
|
|
{
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VM_BUG_ON_PAGE(!PageSlab(page), page);
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|
return PageActive(page);
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|
}
|
|
|
|
/*
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* A version of PageSlabPfmemalloc() for opportunistic checks where the page
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|
* might have been freed under us and not be a PageSlab anymore.
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|
*/
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|
static inline int __PageSlabPfmemalloc(struct page *page)
|
|
{
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|
return PageActive(page);
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|
}
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|
|
|
static inline void SetPageSlabPfmemalloc(struct page *page)
|
|
{
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|
VM_BUG_ON_PAGE(!PageSlab(page), page);
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|
SetPageActive(page);
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|
}
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|
|
|
static inline void __ClearPageSlabPfmemalloc(struct page *page)
|
|
{
|
|
VM_BUG_ON_PAGE(!PageSlab(page), page);
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|
__ClearPageActive(page);
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|
}
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|
|
|
static inline void ClearPageSlabPfmemalloc(struct page *page)
|
|
{
|
|
VM_BUG_ON_PAGE(!PageSlab(page), page);
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|
ClearPageActive(page);
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|
}
|
|
|
|
#ifdef CONFIG_MMU
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|
#define __PG_MLOCKED (1UL << PG_mlocked)
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|
#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)
|
|
|
|
/*
|
|
* 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)
|
|
|
|
#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 */
|