![David Hildenbrand](/assets/img/avatar_default.png)
The usage of PG_reserved and how PG_reserved pages are to be treated is buried deep down in different parts of the kernel. Let's shine some light onto these details by documenting current users and expected behavior. Especially, clarify on the "Some of them might not even exist" case. These are physical memory gaps that will never be dumped as they are not marked as IORESOURCE_SYSRAM. PG_reserved does in general not hinder anybody from dumping or swapping. In some cases, these pages will not be stored in the hibernation image. Link: http://lkml.kernel.org/r/20190114125903.24845-10-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Pavel Tatashin <pasha.tatashin@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Anthony Yznaga <anthony.yznaga@oracle.com> Cc: Miles Chen <miles.chen@mediatek.com> Cc: <yi.z.zhang@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
839 lines
26 KiB
C
839 lines
26 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_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 *_dontuse flags. Use the macros. Otherwise you'll break
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* locked- and dirty-page accounting.
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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_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
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PG_young,
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PG_idle,
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#endif
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__NR_PAGEFLAGS,
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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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/* 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_private_2,
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/* non-lru isolated movable page */
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PG_isolated = PG_reclaim,
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};
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#ifndef __GENERATING_BOUNDS_H
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struct page; /* forward declaration */
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static inline struct page *compound_head(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 (struct page *) (head - 1);
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return page;
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}
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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 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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/*
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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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#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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/*
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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 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 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 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 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 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 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 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) \
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static inline int Page##uname(const struct page *page) { return 0; }
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#define SETPAGEFLAG_NOOP(uname) \
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static inline void SetPage##uname(struct page *page) { }
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#define CLEARPAGEFLAG_NOOP(uname) \
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static inline void ClearPage##uname(struct page *page) { }
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#define __CLEARPAGEFLAG_NOOP(uname) \
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static inline void __ClearPage##uname(struct page *page) { }
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#define TESTSETFLAG_FALSE(uname) \
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static inline int TestSetPage##uname(struct page *page) { return 0; }
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#define TESTCLEARFLAG_FALSE(uname) \
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static inline int TestClearPage##uname(struct page *page) { return 0; }
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#define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \
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SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname)
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#define TESTSCFLAG_FALSE(uname) \
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TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
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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_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND)
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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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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)
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PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
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PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
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PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
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__CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
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__SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
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PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
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__CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
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__SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
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/*
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* Private page markings that may be used by the filesystem that owns the page
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* for its own purposes.
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* - PG_private and PG_private_2 cause releasepage() and co to be invoked
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*/
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PAGEFLAG(Private, private, PF_ANY) __SETPAGEFLAG(Private, private, PF_ANY)
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__CLEARPAGEFLAG(Private, private, PF_ANY)
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PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY)
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PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
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TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
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/*
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* Only test-and-set exist for PG_writeback. The unconditional operators are
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* risky: they bypass page accounting.
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*/
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TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL)
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TESTSCFLAG(Writeback, writeback, PF_NO_TAIL)
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PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL)
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/* PG_readahead is only used for reads; PG_reclaim is only for writes */
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PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL)
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TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL)
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PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND)
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TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND)
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#ifdef CONFIG_HIGHMEM
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/*
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* Must use a macro here due to header dependency issues. page_zone() is not
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* available at this point.
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*/
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#define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
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#else
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PAGEFLAG_FALSE(HighMem)
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#endif
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#ifdef CONFIG_SWAP
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static __always_inline int PageSwapCache(struct page *page)
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{
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#ifdef CONFIG_THP_SWAP
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page = compound_head(page);
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#endif
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return PageSwapBacked(page) && test_bit(PG_swapcache, &page->flags);
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}
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SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
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CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
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#else
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PAGEFLAG_FALSE(SwapCache)
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#endif
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PAGEFLAG(Unevictable, unevictable, PF_HEAD)
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__CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD)
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TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD)
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#ifdef CONFIG_MMU
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PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
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__CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
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TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL)
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#else
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PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked)
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TESTSCFLAG_FALSE(Mlocked)
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#endif
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#ifdef CONFIG_ARCH_USES_PG_UNCACHED
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PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND)
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#else
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PAGEFLAG_FALSE(Uncached)
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#endif
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#ifdef CONFIG_MEMORY_FAILURE
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PAGEFLAG(HWPoison, hwpoison, PF_ANY)
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TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
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#define __PG_HWPOISON (1UL << PG_hwpoison)
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extern bool set_hwpoison_free_buddy_page(struct page *page);
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#else
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PAGEFLAG_FALSE(HWPoison)
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static inline bool set_hwpoison_free_buddy_page(struct page *page)
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{
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return 0;
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}
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#define __PG_HWPOISON 0
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#endif
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#if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
|
|
TESTPAGEFLAG(Young, young, PF_ANY)
|
|
SETPAGEFLAG(Young, young, PF_ANY)
|
|
TESTCLEARFLAG(Young, young, PF_ANY)
|
|
PAGEFLAG(Idle, idle, PF_ANY)
|
|
#endif
|
|
|
|
/*
|
|
* On an anonymous page mapped into a user virtual memory area,
|
|
* page->mapping points to its anon_vma, not to a struct address_space;
|
|
* with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h.
|
|
*
|
|
* On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
|
|
* the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON
|
|
* bit; and then page->mapping points, not to an anon_vma, but to a private
|
|
* structure which KSM associates with that merged page. See ksm.h.
|
|
*
|
|
* PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable
|
|
* page and then page->mapping points a struct address_space.
|
|
*
|
|
* Please note that, confusingly, "page_mapping" refers to the inode
|
|
* address_space which maps the page from disk; whereas "page_mapped"
|
|
* refers to user virtual address space into which the page is mapped.
|
|
*/
|
|
#define PAGE_MAPPING_ANON 0x1
|
|
#define PAGE_MAPPING_MOVABLE 0x2
|
|
#define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
|
|
#define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
|
|
|
|
static __always_inline int PageMappingFlags(struct page *page)
|
|
{
|
|
return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0;
|
|
}
|
|
|
|
static __always_inline int PageAnon(struct page *page)
|
|
{
|
|
page = compound_head(page);
|
|
return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
|
|
}
|
|
|
|
static __always_inline int __PageMovable(struct page *page)
|
|
{
|
|
return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
|
|
PAGE_MAPPING_MOVABLE;
|
|
}
|
|
|
|
#ifdef CONFIG_KSM
|
|
/*
|
|
* A KSM page is one of those write-protected "shared pages" or "merged pages"
|
|
* which KSM maps into multiple mms, wherever identical anonymous page content
|
|
* is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any
|
|
* anon_vma, but to that page's node of the stable tree.
|
|
*/
|
|
static __always_inline int PageKsm(struct page *page)
|
|
{
|
|
page = compound_head(page);
|
|
return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
|
|
PAGE_MAPPING_KSM;
|
|
}
|
|
#else
|
|
TESTPAGEFLAG_FALSE(Ksm)
|
|
#endif
|
|
|
|
u64 stable_page_flags(struct page *page);
|
|
|
|
static inline int PageUptodate(struct page *page)
|
|
{
|
|
int ret;
|
|
page = compound_head(page);
|
|
ret = test_bit(PG_uptodate, &(page)->flags);
|
|
/*
|
|
* Must ensure that the data we read out of the page is loaded
|
|
* _after_ we've loaded page->flags to check for PageUptodate.
|
|
* We can skip the barrier if the page is not uptodate, because
|
|
* we wouldn't be reading anything from it.
|
|
*
|
|
* See SetPageUptodate() for the other side of the story.
|
|
*/
|
|
if (ret)
|
|
smp_rmb();
|
|
|
|
return ret;
|
|
}
|
|
|
|
static __always_inline void __SetPageUptodate(struct page *page)
|
|
{
|
|
VM_BUG_ON_PAGE(PageTail(page), page);
|
|
smp_wmb();
|
|
__set_bit(PG_uptodate, &page->flags);
|
|
}
|
|
|
|
static __always_inline void SetPageUptodate(struct page *page)
|
|
{
|
|
VM_BUG_ON_PAGE(PageTail(page), page);
|
|
/*
|
|
* Memory barrier must be issued before setting the PG_uptodate bit,
|
|
* so that all previous stores issued in order to bring the page
|
|
* uptodate are actually visible before PageUptodate becomes true.
|
|
*/
|
|
smp_wmb();
|
|
set_bit(PG_uptodate, &page->flags);
|
|
}
|
|
|
|
CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)
|
|
|
|
int test_clear_page_writeback(struct page *page);
|
|
int __test_set_page_writeback(struct page *page, bool keep_write);
|
|
|
|
#define test_set_page_writeback(page) \
|
|
__test_set_page_writeback(page, false)
|
|
#define test_set_page_writeback_keepwrite(page) \
|
|
__test_set_page_writeback(page, true)
|
|
|
|
static inline void set_page_writeback(struct page *page)
|
|
{
|
|
test_set_page_writeback(page);
|
|
}
|
|
|
|
static inline void set_page_writeback_keepwrite(struct page *page)
|
|
{
|
|
test_set_page_writeback_keepwrite(page);
|
|
}
|
|
|
|
__PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY)
|
|
|
|
static __always_inline void set_compound_head(struct page *page, struct page *head)
|
|
{
|
|
WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
|
|
}
|
|
|
|
static __always_inline void clear_compound_head(struct page *page)
|
|
{
|
|
WRITE_ONCE(page->compound_head, 0);
|
|
}
|
|
|
|
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
|
static inline void ClearPageCompound(struct page *page)
|
|
{
|
|
BUG_ON(!PageHead(page));
|
|
ClearPageHead(page);
|
|
}
|
|
#endif
|
|
|
|
#define PG_head_mask ((1UL << PG_head))
|
|
|
|
#ifdef CONFIG_HUGETLB_PAGE
|
|
int PageHuge(struct page *page);
|
|
int PageHeadHuge(struct page *page);
|
|
bool page_huge_active(struct page *page);
|
|
#else
|
|
TESTPAGEFLAG_FALSE(Huge)
|
|
TESTPAGEFLAG_FALSE(HeadHuge)
|
|
|
|
static inline bool page_huge_active(struct page *page)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
|
|
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
|
/*
|
|
* PageHuge() only returns true for hugetlbfs pages, but not for
|
|
* normal or transparent huge pages.
|
|
*
|
|
* PageTransHuge() returns true for both transparent huge and
|
|
* hugetlbfs pages, but not normal pages. PageTransHuge() can only be
|
|
* called only in the core VM paths where hugetlbfs pages can't exist.
|
|
*/
|
|
static inline int PageTransHuge(struct page *page)
|
|
{
|
|
VM_BUG_ON_PAGE(PageTail(page), page);
|
|
return PageHead(page);
|
|
}
|
|
|
|
/*
|
|
* PageTransCompound returns true for both transparent huge pages
|
|
* and hugetlbfs pages, so it should only be called when it's known
|
|
* that hugetlbfs pages aren't involved.
|
|
*/
|
|
static inline int PageTransCompound(struct page *page)
|
|
{
|
|
return PageCompound(page);
|
|
}
|
|
|
|
/*
|
|
* PageTransCompoundMap is the same as PageTransCompound, but it also
|
|
* guarantees the primary MMU has the entire compound page mapped
|
|
* through pmd_trans_huge, which in turn guarantees the secondary MMUs
|
|
* can also map the entire compound page. This allows the secondary
|
|
* MMUs to call get_user_pages() only once for each compound page and
|
|
* to immediately map the entire compound page with a single secondary
|
|
* MMU fault. If there will be a pmd split later, the secondary MMUs
|
|
* will get an update through the MMU notifier invalidation through
|
|
* split_huge_pmd().
|
|
*
|
|
* Unlike PageTransCompound, this is safe to be called only while
|
|
* split_huge_pmd() cannot run from under us, like if protected by the
|
|
* MMU notifier, otherwise it may result in page->_mapcount < 0 false
|
|
* positives.
|
|
*/
|
|
static inline int PageTransCompoundMap(struct page *page)
|
|
{
|
|
return PageTransCompound(page) && atomic_read(&page->_mapcount) < 0;
|
|
}
|
|
|
|
/*
|
|
* PageTransTail returns true for both transparent huge pages
|
|
* and hugetlbfs pages, so it should only be called when it's known
|
|
* that hugetlbfs pages aren't involved.
|
|
*/
|
|
static inline int PageTransTail(struct page *page)
|
|
{
|
|
return PageTail(page);
|
|
}
|
|
|
|
/*
|
|
* PageDoubleMap indicates that the compound page is mapped with PTEs as well
|
|
* as PMDs.
|
|
*
|
|
* This is required for optimization of rmap operations for THP: we can postpone
|
|
* per small page mapcount accounting (and its overhead from atomic operations)
|
|
* until the first PMD split.
|
|
*
|
|
* For the page PageDoubleMap means ->_mapcount in all sub-pages is offset up
|
|
* by one. This reference will go away with last compound_mapcount.
|
|
*
|
|
* See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap().
|
|
*/
|
|
static inline int PageDoubleMap(struct page *page)
|
|
{
|
|
return PageHead(page) && test_bit(PG_double_map, &page[1].flags);
|
|
}
|
|
|
|
static inline void SetPageDoubleMap(struct page *page)
|
|
{
|
|
VM_BUG_ON_PAGE(!PageHead(page), page);
|
|
set_bit(PG_double_map, &page[1].flags);
|
|
}
|
|
|
|
static inline void ClearPageDoubleMap(struct page *page)
|
|
{
|
|
VM_BUG_ON_PAGE(!PageHead(page), page);
|
|
clear_bit(PG_double_map, &page[1].flags);
|
|
}
|
|
static inline int TestSetPageDoubleMap(struct page *page)
|
|
{
|
|
VM_BUG_ON_PAGE(!PageHead(page), page);
|
|
return test_and_set_bit(PG_double_map, &page[1].flags);
|
|
}
|
|
|
|
static inline int TestClearPageDoubleMap(struct page *page)
|
|
{
|
|
VM_BUG_ON_PAGE(!PageHead(page), page);
|
|
return test_and_clear_bit(PG_double_map, &page[1].flags);
|
|
}
|
|
|
|
#else
|
|
TESTPAGEFLAG_FALSE(TransHuge)
|
|
TESTPAGEFLAG_FALSE(TransCompound)
|
|
TESTPAGEFLAG_FALSE(TransCompoundMap)
|
|
TESTPAGEFLAG_FALSE(TransTail)
|
|
PAGEFLAG_FALSE(DoubleMap)
|
|
TESTSETFLAG_FALSE(DoubleMap)
|
|
TESTCLEARFLAG_FALSE(DoubleMap)
|
|
#endif
|
|
|
|
/*
|
|
* For pages that are never mapped to userspace (and aren't PageSlab),
|
|
* page_type may be used. Because it is initialised to -1, we invert the
|
|
* sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and
|
|
* __ClearPageFoo *sets* the bit used for PageFoo. We reserve a few high and
|
|
* low bits so that an underflow or overflow of page_mapcount() won't be
|
|
* mistaken for a page type value.
|
|
*/
|
|
|
|
#define PAGE_TYPE_BASE 0xf0000000
|
|
/* Reserve 0x0000007f to catch underflows of page_mapcount */
|
|
#define PAGE_MAPCOUNT_RESERVE -128
|
|
#define PG_buddy 0x00000080
|
|
#define PG_offline 0x00000100
|
|
#define PG_kmemcg 0x00000200
|
|
#define PG_table 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.
|
|
*/
|
|
PAGE_TYPE_OPS(Offline, offline)
|
|
|
|
/*
|
|
* If kmemcg is enabled, the buddy allocator will set PageKmemcg() on
|
|
* pages allocated with __GFP_ACCOUNT. It gets cleared on page free.
|
|
*/
|
|
PAGE_TYPE_OPS(Kmemcg, kmemcg)
|
|
|
|
/*
|
|
* Marks pages in use as page tables.
|
|
*/
|
|
PAGE_TYPE_OPS(Table, table)
|
|
|
|
extern bool is_free_buddy_page(struct page *page);
|
|
|
|
__PAGEFLAG(Isolated, isolated, PF_ANY);
|
|
|
|
/*
|
|
* If network-based swap is enabled, sl*b must keep track of whether pages
|
|
* were allocated from pfmemalloc reserves.
|
|
*/
|
|
static inline int PageSlabPfmemalloc(struct page *page)
|
|
{
|
|
VM_BUG_ON_PAGE(!PageSlab(page), page);
|
|
return PageActive(page);
|
|
}
|
|
|
|
static inline void SetPageSlabPfmemalloc(struct page *page)
|
|
{
|
|
VM_BUG_ON_PAGE(!PageSlab(page), page);
|
|
SetPageActive(page);
|
|
}
|
|
|
|
static inline void __ClearPageSlabPfmemalloc(struct page *page)
|
|
{
|
|
VM_BUG_ON_PAGE(!PageSlab(page), page);
|
|
__ClearPageActive(page);
|
|
}
|
|
|
|
static inline void ClearPageSlabPfmemalloc(struct page *page)
|
|
{
|
|
VM_BUG_ON_PAGE(!PageSlab(page), page);
|
|
ClearPageActive(page);
|
|
}
|
|
|
|
#ifdef CONFIG_MMU
|
|
#define __PG_MLOCKED (1UL << PG_mlocked)
|
|
#else
|
|
#define __PG_MLOCKED 0
|
|
#endif
|
|
|
|
/*
|
|
* Flags checked when a page is freed. Pages being freed should not have
|
|
* these flags set. It they are, there is a problem.
|
|
*/
|
|
#define PAGE_FLAGS_CHECK_AT_FREE \
|
|
(1UL << PG_lru | 1UL << PG_locked | \
|
|
1UL << PG_private | 1UL << PG_private_2 | \
|
|
1UL << PG_writeback | 1UL << PG_reserved | \
|
|
1UL << PG_slab | 1UL << PG_active | \
|
|
1UL << PG_unevictable | __PG_MLOCKED)
|
|
|
|
/*
|
|
* Flags checked when a page is prepped for return by the page allocator.
|
|
* Pages being prepped should not have these flags set. It they are set,
|
|
* there has been a kernel bug or struct page corruption.
|
|
*
|
|
* __PG_HWPOISON is exceptional because it needs to be kept beyond page's
|
|
* alloc-free cycle to prevent from reusing the page.
|
|
*/
|
|
#define PAGE_FLAGS_CHECK_AT_PREP \
|
|
(((1UL << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON)
|
|
|
|
#define PAGE_FLAGS_PRIVATE \
|
|
(1UL << PG_private | 1UL << PG_private_2)
|
|
/**
|
|
* page_has_private - Determine if page has private stuff
|
|
* @page: The page to be checked
|
|
*
|
|
* Determine if a page has private stuff, indicating that release routines
|
|
* should be invoked upon it.
|
|
*/
|
|
static inline int page_has_private(struct page *page)
|
|
{
|
|
return !!(page->flags & PAGE_FLAGS_PRIVATE);
|
|
}
|
|
|
|
#undef PF_ANY
|
|
#undef PF_HEAD
|
|
#undef PF_ONLY_HEAD
|
|
#undef PF_NO_TAIL
|
|
#undef PF_NO_COMPOUND
|
|
#endif /* !__GENERATING_BOUNDS_H */
|
|
|
|
#endif /* PAGE_FLAGS_H */
|