page-flags.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * Macros for manipulating and testing page->flags
   4 */
   5
   6#ifndef PAGE_FLAGS_H
   7#define PAGE_FLAGS_H
   8
   9#include <linux/types.h>
  10#include <linux/bug.h>
  11#include <linux/mmdebug.h>
  12#ifndef __GENERATING_BOUNDS_H
  13#include <linux/mm_types.h>
  14#include <generated/bounds.h>
  15#endif /* !__GENERATING_BOUNDS_H */
  16
  17/*
  18 * Various page->flags bits:
  19 *
  20 * PG_reserved is set for special pages. The "struct page" of such a page
  21 * should in general not be touched (e.g. set dirty) except by its owner.
  22 * Pages marked as PG_reserved include:
  23 * - Pages part of the kernel image (including vDSO) and similar (e.g. BIOS,
  24 *   initrd, HW tables)
  25 * - Pages reserved or allocated early during boot (before the page allocator
  26 *   was initialized). This includes (depending on the architecture) the
  27 *   initial vmemmap, initial page tables, crashkernel, elfcorehdr, and much
  28 *   much more. Once (if ever) freed, PG_reserved is cleared and they will
  29 *   be given to the page allocator.
  30 * - Pages falling into physical memory gaps - not IORESOURCE_SYSRAM. Trying
  31 *   to read/write these pages might end badly. Don't touch!
  32 * - The zero page(s)
  33 * - Pages allocated in the context of kexec/kdump (loaded kernel image,
  34 *   control pages, vmcoreinfo)
  35 * - MMIO/DMA pages. Some architectures don't allow to ioremap pages that are
  36 *   not marked PG_reserved (as they might be in use by somebody else who does
  37 *   not respect the caching strategy).
  38 * - MCA pages on ia64
  39 * - Pages holding CPU notes for POWER Firmware Assisted Dump
  40 * - Device memory (e.g. PMEM, DAX, HMM)
  41 * Some PG_reserved pages will be excluded from the hibernation image.
  42 * PG_reserved does in general not hinder anybody from dumping or swapping
  43 * and is no longer required for remap_pfn_range(). ioremap might require it.
  44 * Consequently, PG_reserved for a page mapped into user space can indicate
  45 * the zero page, the vDSO, MMIO pages or device memory.
  46 *
  47 * The PG_private bitflag is set on pagecache pages if they contain filesystem
  48 * specific data (which is normally at page->private). It can be used by
  49 * private allocations for its own usage.
  50 *
  51 * During initiation of disk I/O, PG_locked is set. This bit is set before I/O
  52 * and cleared when writeback _starts_ or when read _completes_. PG_writeback
  53 * is set before writeback starts and cleared when it finishes.
  54 *
  55 * PG_locked also pins a page in pagecache, and blocks truncation of the file
  56 * while it is held.
  57 *
  58 * page_waitqueue(page) is a wait queue of all tasks waiting for the page
  59 * to become unlocked.
  60 *
  61 * PG_swapbacked is set when a page uses swap as a backing storage.  This are
  62 * usually PageAnon or shmem pages but please note that even anonymous pages
  63 * might lose their PG_swapbacked flag when they simply can be dropped (e.g. as
  64 * a result of MADV_FREE).
  65 *
  66 * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
  67 * file-backed pagecache (see mm/vmscan.c).
  68 *
  69 * PG_arch_1 is an architecture specific page state bit.  The generic code
  70 * guarantees that this bit is cleared for a page when it first is entered into
  71 * the page cache.
  72 *
  73 * PG_hwpoison indicates that a page got corrupted in hardware and contains
  74 * data with incorrect ECC bits that triggered a machine check. Accessing is
  75 * not safe since it may cause another machine check. Don't touch!
  76 */
  77
  78/*
  79 * Don't use the pageflags directly.  Use the PageFoo macros.
  80 *
  81 * The page flags field is split into two parts, the main flags area
  82 * which extends from the low bits upwards, and the fields area which
  83 * extends from the high bits downwards.
  84 *
  85 *  | FIELD | ... | FLAGS |
  86 *  N-1           ^       0
  87 *               (NR_PAGEFLAGS)
  88 *
  89 * The fields area is reserved for fields mapping zone, node (for NUMA) and
  90 * SPARSEMEM section (for variants of SPARSEMEM that require section ids like
  91 * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
  92 */
  93enum pageflags {
  94	PG_locked,		/* Page is locked. Don't touch. */
  95	PG_writeback,		/* Page is under writeback */
  96	PG_referenced,
  97	PG_uptodate,
  98	PG_dirty,
  99	PG_lru,
 100	PG_head,		/* Must be in bit 6 */
 101	PG_waiters,		/* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
 102	PG_active,
 103	PG_workingset,
 104	PG_owner_priv_1,	/* Owner use. If pagecache, fs may use */
 105	PG_owner_2,		/* Owner use. If pagecache, fs may use */
 106	PG_arch_1,
 107	PG_reserved,
 108	PG_private,		/* If pagecache, has fs-private data */
 109	PG_private_2,		/* If pagecache, has fs aux data */
 110	PG_reclaim,		/* To be reclaimed asap */
 111	PG_swapbacked,		/* Page is backed by RAM/swap */
 112	PG_unevictable,		/* Page is "unevictable"  */
 113	PG_dropbehind,		/* drop pages on IO completion */
 114#ifdef CONFIG_MMU
 115	PG_mlocked,		/* Page is vma mlocked */
 116#endif
 117#ifdef CONFIG_MEMORY_FAILURE
 118	PG_hwpoison,		/* hardware poisoned page. Don't touch */
 119#endif
 120#if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT)
 121	PG_young,
 122	PG_idle,
 123#endif
 124#ifdef CONFIG_ARCH_USES_PG_ARCH_2
 125	PG_arch_2,
 126#endif
 127#ifdef CONFIG_ARCH_USES_PG_ARCH_3
 128	PG_arch_3,
 129#endif
 130	__NR_PAGEFLAGS,
 131
 132	PG_readahead = PG_reclaim,
 133
 134	/* Anonymous memory (and shmem) */
 135	PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */
 136	/* Some filesystems */
 137	PG_checked = PG_owner_priv_1,
 138
 139	/*
 140	 * Depending on the way an anonymous folio can be mapped into a page
 141	 * table (e.g., single PMD/PUD/CONT of the head page vs. PTE-mapped
 142	 * THP), PG_anon_exclusive may be set only for the head page or for
 143	 * tail pages of an anonymous folio. For now, we only expect it to be
 144	 * set on tail pages for PTE-mapped THP.
 145	 */
 146	PG_anon_exclusive = PG_owner_2,
 147
 148	/*
 149	 * Set if all buffer heads in the folio are mapped.
 150	 * Filesystems which do not use BHs can use it for their own purpose.
 151	 */
 152	PG_mappedtodisk = PG_owner_2,
 153
 154	/* Two page bits are conscripted by FS-Cache to maintain local caching
 155	 * state.  These bits are set on pages belonging to the netfs's inodes
 156	 * when those inodes are being locally cached.
 157	 */
 158	PG_fscache = PG_private_2,	/* page backed by cache */
 159
 160	/* XEN */
 161	/* Pinned in Xen as a read-only pagetable page. */
 162	PG_pinned = PG_owner_priv_1,
 163	/* Pinned as part of domain save (see xen_mm_pin_all()). */
 164	PG_savepinned = PG_dirty,
 165	/* Has a grant mapping of another (foreign) domain's page. */
 166	PG_foreign = PG_owner_priv_1,
 167	/* Remapped by swiotlb-xen. */
 168	PG_xen_remapped = PG_owner_priv_1,
 169
 170#ifdef CONFIG_MIGRATION
 171	/* movable_ops page that is isolated for migration */
 172	PG_movable_ops_isolated = PG_reclaim,
 173	/* this is a movable_ops page (for selected typed pages only) */
 174	PG_movable_ops = PG_uptodate,
 175#endif
 176
 177	/* Only valid for buddy pages. Used to track pages that are reported */
 178	PG_reported = PG_uptodate,
 179
 180#ifdef CONFIG_MEMORY_HOTPLUG
 181	/* For self-hosted memmap pages */
 182	PG_vmemmap_self_hosted = PG_owner_priv_1,
 183#endif
 184
 185	/*
 186	 * Flags only valid for compound pages.  Stored in first tail page's
 187	 * flags word.  Cannot use the first 8 flags or any flag marked as
 188	 * PF_ANY.
 189	 */
 190
 191	/* At least one page in this folio has the hwpoison flag set */
 192	PG_has_hwpoisoned = PG_active,
 193	PG_large_rmappable = PG_workingset, /* anon or file-backed */
 194	PG_partially_mapped = PG_reclaim, /* was identified to be partially mapped */
 195};
 196
 197#define PAGEFLAGS_MASK		((1UL << NR_PAGEFLAGS) - 1)
 198
 199#ifndef __GENERATING_BOUNDS_H
 200
 201#ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
 202DECLARE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key);
 203
 204/*
 205 * Return the real head page struct iff the @page is a fake head page, otherwise
 206 * return the @page itself. See Documentation/mm/vmemmap_dedup.rst.
 207 */
 208static __always_inline const struct page *page_fixed_fake_head(const struct page *page)
 209{
 210	if (!static_branch_unlikely(&hugetlb_optimize_vmemmap_key))
 211		return page;
 212
 213	/*
 214	 * Only addresses aligned with PAGE_SIZE of struct page may be fake head
 215	 * struct page. The alignment check aims to avoid access the fields (
 216	 * e.g. compound_head) of the @page[1]. It can avoid touch a (possibly)
 217	 * cold cacheline in some cases.
 218	 */
 219	if (IS_ALIGNED((unsigned long)page, PAGE_SIZE) &&
 220	    test_bit(PG_head, &page->flags.f)) {
 221		/*
 222		 * We can safely access the field of the @page[1] with PG_head
 223		 * because the @page is a compound page composed with at least
 224		 * two contiguous pages.
 225		 */
 226		unsigned long head = READ_ONCE(page[1].compound_head);
 227
 228		if (likely(head & 1))
 229			return (const struct page *)(head - 1);
 230	}
 231	return page;
 232}
 233
 234static __always_inline bool page_count_writable(const struct page *page, int u)
 235{
 236	if (!static_branch_unlikely(&hugetlb_optimize_vmemmap_key))
 237		return true;
 238
 239	/*
 240	 * The refcount check is ordered before the fake-head check to prevent
 241	 * the following race:
 242	 *   CPU 1 (HVO)                     CPU 2 (speculative PFN walker)
 243	 *
 244	 *   page_ref_freeze()
 245	 *   synchronize_rcu()
 246	 *                                   rcu_read_lock()
 247	 *                                   page_is_fake_head() is false
 248	 *   vmemmap_remap_pte()
 249	 *   XXX: struct page[] becomes r/o
 250	 *
 251	 *   page_ref_unfreeze()
 252	 *                                   page_ref_count() is not zero
 253	 *
 254	 *                                   atomic_add_unless(&page->_refcount)
 255	 *                                   XXX: try to modify r/o struct page[]
 256	 *
 257	 * The refcount check also prevents modification attempts to other (r/o)
 258	 * tail pages that are not fake heads.
 259	 */
 260	if (atomic_read_acquire(&page->_refcount) == u)
 261		return false;
 262
 263	return page_fixed_fake_head(page) == page;
 264}
 265#else
 266static inline const struct page *page_fixed_fake_head(const struct page *page)
 267{
 268	return page;
 269}
 270
 271static inline bool page_count_writable(const struct page *page, int u)
 272{
 273	return true;
 274}
 275#endif
 276
 277static __always_inline int page_is_fake_head(const struct page *page)
 278{
 279	return page_fixed_fake_head(page) != page;
 280}
 281
 282static __always_inline unsigned long _compound_head(const struct page *page)
 283{
 284	unsigned long head = READ_ONCE(page->compound_head);
 285
 286	if (unlikely(head & 1))
 287		return head - 1;
 288	return (unsigned long)page_fixed_fake_head(page);
 289}
 290
 291#define compound_head(page)	((typeof(page))_compound_head(page))
 292
 293/**
 294 * page_folio - Converts from page to folio.
 295 * @p: The page.
 296 *
 297 * Every page is part of a folio.  This function cannot be called on a
 298 * NULL pointer.
 299 *
 300 * Context: No reference, nor lock is required on @page.  If the caller
 301 * does not hold a reference, this call may race with a folio split, so
 302 * it should re-check the folio still contains this page after gaining
 303 * a reference on the folio.
 304 * Return: The folio which contains this page.
 305 */
 306#define page_folio(p)		(_Generic((p),				\
 307	const struct page *:	(const struct folio *)_compound_head(p), \
 308	struct page *:		(struct folio *)_compound_head(p)))
 309
 310/**
 311 * folio_page - Return a page from a folio.
 312 * @folio: The folio.
 313 * @n: The page number to return.
 314 *
 315 * @n is relative to the start of the folio.  This function does not
 316 * check that the page number lies within @folio; the caller is presumed
 317 * to have a reference to the page.
 318 */
 319#define folio_page(folio, n)	(&(folio)->page + (n))
 320
 321static __always_inline int PageTail(const struct page *page)
 322{
 323	return READ_ONCE(page->compound_head) & 1 || page_is_fake_head(page);
 324}
 325
 326static __always_inline int PageCompound(const struct page *page)
 327{
 328	return test_bit(PG_head, &page->flags.f) ||
 329	       READ_ONCE(page->compound_head) & 1;
 330}
 331
 332#define	PAGE_POISON_PATTERN	-1l
 333static inline int PagePoisoned(const struct page *page)
 334{
 335	return READ_ONCE(page->flags.f) == PAGE_POISON_PATTERN;
 336}
 337
 338#ifdef CONFIG_DEBUG_VM
 339void page_init_poison(struct page *page, size_t size);
 340#else
 341static inline void page_init_poison(struct page *page, size_t size)
 342{
 343}
 344#endif
 345
 346static const unsigned long *const_folio_flags(const struct folio *folio,
 347		unsigned n)
 348{
 349	const struct page *page = &folio->page;
 350
 351	VM_BUG_ON_PGFLAGS(page->compound_head & 1, page);
 352	VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags.f), page);
 353	return &page[n].flags.f;
 354}
 355
 356static unsigned long *folio_flags(struct folio *folio, unsigned n)
 357{
 358	struct page *page = &folio->page;
 359
 360	VM_BUG_ON_PGFLAGS(page->compound_head & 1, page);
 361	VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags.f), page);
 362	return &page[n].flags.f;
 363}
 364
 365/*
 366 * Page flags policies wrt compound pages
 367 *
 368 * PF_POISONED_CHECK
 369 *     check if this struct page poisoned/uninitialized
 370 *
 371 * PF_ANY:
 372 *     the page flag is relevant for small, head and tail pages.
 373 *
 374 * PF_HEAD:
 375 *     for compound page all operations related to the page flag applied to
 376 *     head page.
 377 *
 378 * PF_NO_TAIL:
 379 *     modifications of the page flag must be done on small or head pages,
 380 *     checks can be done on tail pages too.
 381 *
 382 * PF_NO_COMPOUND:
 383 *     the page flag is not relevant for compound pages.
 384 *
 385 * PF_SECOND:
 386 *     the page flag is stored in the first tail page.
 387 */
 388#define PF_POISONED_CHECK(page) ({					\
 389		VM_BUG_ON_PGFLAGS(PagePoisoned(page), page);		\
 390		page; })
 391#define PF_ANY(page, enforce)	PF_POISONED_CHECK(page)
 392#define PF_HEAD(page, enforce)	PF_POISONED_CHECK(compound_head(page))
 393#define PF_NO_TAIL(page, enforce) ({					\
 394		VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page);	\
 395		PF_POISONED_CHECK(compound_head(page)); })
 396#define PF_NO_COMPOUND(page, enforce) ({				\
 397		VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page);	\
 398		PF_POISONED_CHECK(page); })
 399#define PF_SECOND(page, enforce) ({					\
 400		VM_BUG_ON_PGFLAGS(!PageHead(page), page);		\
 401		PF_POISONED_CHECK(&page[1]); })
 402
 403/* Which page is the flag stored in */
 404#define FOLIO_PF_ANY		0
 405#define FOLIO_PF_HEAD		0
 406#define FOLIO_PF_NO_TAIL	0
 407#define FOLIO_PF_NO_COMPOUND	0
 408#define FOLIO_PF_SECOND		1
 409
 410#define FOLIO_HEAD_PAGE		0
 411#define FOLIO_SECOND_PAGE	1
 412
 413/*
 414 * Macros to create function definitions for page flags
 415 */
 416#define FOLIO_TEST_FLAG(name, page)					\
 417static __always_inline bool folio_test_##name(const struct folio *folio) \
 418{ return test_bit(PG_##name, const_folio_flags(folio, page)); }
 419
 420#define FOLIO_SET_FLAG(name, page)					\
 421static __always_inline void folio_set_##name(struct folio *folio)	\
 422{ set_bit(PG_##name, folio_flags(folio, page)); }
 423
 424#define FOLIO_CLEAR_FLAG(name, page)					\
 425static __always_inline void folio_clear_##name(struct folio *folio)	\
 426{ clear_bit(PG_##name, folio_flags(folio, page)); }
 427
 428#define __FOLIO_SET_FLAG(name, page)					\
 429static __always_inline void __folio_set_##name(struct folio *folio)	\
 430{ __set_bit(PG_##name, folio_flags(folio, page)); }
 431
 432#define __FOLIO_CLEAR_FLAG(name, page)					\
 433static __always_inline void __folio_clear_##name(struct folio *folio)	\
 434{ __clear_bit(PG_##name, folio_flags(folio, page)); }
 435
 436#define FOLIO_TEST_SET_FLAG(name, page)					\
 437static __always_inline bool folio_test_set_##name(struct folio *folio)	\
 438{ return test_and_set_bit(PG_##name, folio_flags(folio, page)); }
 439
 440#define FOLIO_TEST_CLEAR_FLAG(name, page)				\
 441static __always_inline bool folio_test_clear_##name(struct folio *folio) \
 442{ return test_and_clear_bit(PG_##name, folio_flags(folio, page)); }
 443
 444#define FOLIO_FLAG(name, page)						\
 445FOLIO_TEST_FLAG(name, page)						\
 446FOLIO_SET_FLAG(name, page)						\
 447FOLIO_CLEAR_FLAG(name, page)
 448
 449#define TESTPAGEFLAG(uname, lname, policy)				\
 450FOLIO_TEST_FLAG(lname, FOLIO_##policy)					\
 451static __always_inline int Page##uname(const struct page *page)		\
 452{ return test_bit(PG_##lname, &policy(page, 0)->flags.f); }
 453
 454#define SETPAGEFLAG(uname, lname, policy)				\
 455FOLIO_SET_FLAG(lname, FOLIO_##policy)					\
 456static __always_inline void SetPage##uname(struct page *page)		\
 457{ set_bit(PG_##lname, &policy(page, 1)->flags.f); }
 458
 459#define CLEARPAGEFLAG(uname, lname, policy)				\
 460FOLIO_CLEAR_FLAG(lname, FOLIO_##policy)					\
 461static __always_inline void ClearPage##uname(struct page *page)		\
 462{ clear_bit(PG_##lname, &policy(page, 1)->flags.f); }
 463
 464#define __SETPAGEFLAG(uname, lname, policy)				\
 465__FOLIO_SET_FLAG(lname, FOLIO_##policy)					\
 466static __always_inline void __SetPage##uname(struct page *page)		\
 467{ __set_bit(PG_##lname, &policy(page, 1)->flags.f); }
 468
 469#define __CLEARPAGEFLAG(uname, lname, policy)				\
 470__FOLIO_CLEAR_FLAG(lname, FOLIO_##policy)				\
 471static __always_inline void __ClearPage##uname(struct page *page)	\
 472{ __clear_bit(PG_##lname, &policy(page, 1)->flags.f); }
 473
 474#define TESTSETFLAG(uname, lname, policy)				\
 475FOLIO_TEST_SET_FLAG(lname, FOLIO_##policy)				\
 476static __always_inline int TestSetPage##uname(struct page *page)	\
 477{ return test_and_set_bit(PG_##lname, &policy(page, 1)->flags.f); }
 478
 479#define TESTCLEARFLAG(uname, lname, policy)				\
 480FOLIO_TEST_CLEAR_FLAG(lname, FOLIO_##policy)				\
 481static __always_inline int TestClearPage##uname(struct page *page)	\
 482{ return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags.f); }
 483
 484#define PAGEFLAG(uname, lname, policy)					\
 485	TESTPAGEFLAG(uname, lname, policy)				\
 486	SETPAGEFLAG(uname, lname, policy)				\
 487	CLEARPAGEFLAG(uname, lname, policy)
 488
 489#define __PAGEFLAG(uname, lname, policy)				\
 490	TESTPAGEFLAG(uname, lname, policy)				\
 491	__SETPAGEFLAG(uname, lname, policy)				\
 492	__CLEARPAGEFLAG(uname, lname, policy)
 493
 494#define TESTSCFLAG(uname, lname, policy)				\
 495	TESTSETFLAG(uname, lname, policy)				\
 496	TESTCLEARFLAG(uname, lname, policy)
 497
 498#define FOLIO_TEST_FLAG_FALSE(name)					\
 499static inline bool folio_test_##name(const struct folio *folio)		\
 500{ return false; }
 501#define FOLIO_SET_FLAG_NOOP(name)					\
 502static inline void folio_set_##name(struct folio *folio) { }
 503#define FOLIO_CLEAR_FLAG_NOOP(name)					\
 504static inline void folio_clear_##name(struct folio *folio) { }
 505#define __FOLIO_SET_FLAG_NOOP(name)					\
 506static inline void __folio_set_##name(struct folio *folio) { }
 507#define __FOLIO_CLEAR_FLAG_NOOP(name)					\
 508static inline void __folio_clear_##name(struct folio *folio) { }
 509#define FOLIO_TEST_SET_FLAG_FALSE(name)					\
 510static inline bool folio_test_set_##name(struct folio *folio)		\
 511{ return false; }
 512#define FOLIO_TEST_CLEAR_FLAG_FALSE(name)				\
 513static inline bool folio_test_clear_##name(struct folio *folio)		\
 514{ return false; }
 515
 516#define FOLIO_FLAG_FALSE(name)						\
 517FOLIO_TEST_FLAG_FALSE(name)						\
 518FOLIO_SET_FLAG_NOOP(name)						\
 519FOLIO_CLEAR_FLAG_NOOP(name)
 520
 521#define TESTPAGEFLAG_FALSE(uname, lname)				\
 522FOLIO_TEST_FLAG_FALSE(lname)						\
 523static inline int Page##uname(const struct page *page) { return 0; }
 524
 525#define SETPAGEFLAG_NOOP(uname, lname)					\
 526FOLIO_SET_FLAG_NOOP(lname)						\
 527static inline void SetPage##uname(struct page *page) {  }
 528
 529#define CLEARPAGEFLAG_NOOP(uname, lname)				\
 530FOLIO_CLEAR_FLAG_NOOP(lname)						\
 531static inline void ClearPage##uname(struct page *page) {  }
 532
 533#define __CLEARPAGEFLAG_NOOP(uname, lname)				\
 534__FOLIO_CLEAR_FLAG_NOOP(lname)						\
 535static inline void __ClearPage##uname(struct page *page) {  }
 536
 537#define TESTSETFLAG_FALSE(uname, lname)					\
 538FOLIO_TEST_SET_FLAG_FALSE(lname)					\
 539static inline int TestSetPage##uname(struct page *page) { return 0; }
 540
 541#define TESTCLEARFLAG_FALSE(uname, lname)				\
 542FOLIO_TEST_CLEAR_FLAG_FALSE(lname)					\
 543static inline int TestClearPage##uname(struct page *page) { return 0; }
 544
 545#define PAGEFLAG_FALSE(uname, lname) TESTPAGEFLAG_FALSE(uname, lname)	\
 546	SETPAGEFLAG_NOOP(uname, lname) CLEARPAGEFLAG_NOOP(uname, lname)
 547
 548#define TESTSCFLAG_FALSE(uname, lname)					\
 549	TESTSETFLAG_FALSE(uname, lname) TESTCLEARFLAG_FALSE(uname, lname)
 550
 551__PAGEFLAG(Locked, locked, PF_NO_TAIL)
 552FOLIO_FLAG(waiters, FOLIO_HEAD_PAGE)
 553FOLIO_FLAG(referenced, FOLIO_HEAD_PAGE)
 554	FOLIO_TEST_CLEAR_FLAG(referenced, FOLIO_HEAD_PAGE)
 555	__FOLIO_SET_FLAG(referenced, FOLIO_HEAD_PAGE)
 556PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
 557	__CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
 558PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
 559	TESTCLEARFLAG(LRU, lru, PF_HEAD)
 560FOLIO_FLAG(active, FOLIO_HEAD_PAGE)
 561	__FOLIO_CLEAR_FLAG(active, FOLIO_HEAD_PAGE)
 562	FOLIO_TEST_CLEAR_FLAG(active, FOLIO_HEAD_PAGE)
 563PAGEFLAG(Workingset, workingset, PF_HEAD)
 564	TESTCLEARFLAG(Workingset, workingset, PF_HEAD)
 565PAGEFLAG(Checked, checked, PF_NO_COMPOUND)	   /* Used by some filesystems */
 566
 567/* Xen */
 568PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
 569	TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)
 570PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
 571PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
 572PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
 573	TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
 574
 575PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
 576	__CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
 577	__SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
 578FOLIO_FLAG(swapbacked, FOLIO_HEAD_PAGE)
 579	__FOLIO_CLEAR_FLAG(swapbacked, FOLIO_HEAD_PAGE)
 580	__FOLIO_SET_FLAG(swapbacked, FOLIO_HEAD_PAGE)
 581
 582/*
 583 * Private page markings that may be used by the filesystem that owns the page
 584 * for its own purposes.
 585 * - PG_private and PG_private_2 cause release_folio() and co to be invoked
 586 */
 587PAGEFLAG(Private, private, PF_ANY)
 588FOLIO_FLAG(private_2, FOLIO_HEAD_PAGE)
 589
 590/* owner_2 can be set on tail pages for anon memory */
 591FOLIO_FLAG(owner_2, FOLIO_HEAD_PAGE)
 592
 593/*
 594 * Only test-and-set exist for PG_writeback.  The unconditional operators are
 595 * risky: they bypass page accounting.
 596 */
 597TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL)
 598	TESTSCFLAG(Writeback, writeback, PF_NO_TAIL)
 599FOLIO_FLAG(mappedtodisk, FOLIO_HEAD_PAGE)
 600
 601/* PG_readahead is only used for reads; PG_reclaim is only for writes */
 602PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL)
 603	TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL)
 604FOLIO_FLAG(readahead, FOLIO_HEAD_PAGE)
 605	FOLIO_TEST_CLEAR_FLAG(readahead, FOLIO_HEAD_PAGE)
 606
 607FOLIO_FLAG(dropbehind, FOLIO_HEAD_PAGE)
 608	FOLIO_TEST_CLEAR_FLAG(dropbehind, FOLIO_HEAD_PAGE)
 609	__FOLIO_SET_FLAG(dropbehind, FOLIO_HEAD_PAGE)
 610
 611#ifdef CONFIG_HIGHMEM
 612/*
 613 * Must use a macro here due to header dependency issues. page_zone() is not
 614 * available at this point.
 615 */
 616#define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
 617#define folio_test_highmem(__f)	is_highmem_idx(folio_zonenum(__f))
 618#else
 619PAGEFLAG_FALSE(HighMem, highmem)
 620#endif
 621#define PhysHighMem(__p) (PageHighMem(phys_to_page(__p)))
 622
 623/* Does kmap_local_folio() only allow access to one page of the folio? */
 624#ifdef CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP
 625#define folio_test_partial_kmap(f)	true
 626#else
 627#define folio_test_partial_kmap(f)	folio_test_highmem(f)
 628#endif
 629
 630#ifdef CONFIG_SWAP
 631static __always_inline bool folio_test_swapcache(const struct folio *folio)
 632{
 633	return folio_test_swapbacked(folio) &&
 634			test_bit(PG_swapcache, const_folio_flags(folio, 0));
 635}
 636
 637FOLIO_SET_FLAG(swapcache, FOLIO_HEAD_PAGE)
 638FOLIO_CLEAR_FLAG(swapcache, FOLIO_HEAD_PAGE)
 639#else
 640FOLIO_FLAG_FALSE(swapcache)
 641#endif
 642
 643FOLIO_FLAG(unevictable, FOLIO_HEAD_PAGE)
 644	__FOLIO_CLEAR_FLAG(unevictable, FOLIO_HEAD_PAGE)
 645	FOLIO_TEST_CLEAR_FLAG(unevictable, FOLIO_HEAD_PAGE)
 646
 647#ifdef CONFIG_MMU
 648FOLIO_FLAG(mlocked, FOLIO_HEAD_PAGE)
 649	__FOLIO_CLEAR_FLAG(mlocked, FOLIO_HEAD_PAGE)
 650	FOLIO_TEST_CLEAR_FLAG(mlocked, FOLIO_HEAD_PAGE)
 651	FOLIO_TEST_SET_FLAG(mlocked, FOLIO_HEAD_PAGE)
 652#else
 653FOLIO_FLAG_FALSE(mlocked)
 654	__FOLIO_CLEAR_FLAG_NOOP(mlocked)
 655	FOLIO_TEST_CLEAR_FLAG_FALSE(mlocked)
 656	FOLIO_TEST_SET_FLAG_FALSE(mlocked)
 657#endif
 658
 659#ifdef CONFIG_MEMORY_FAILURE
 660PAGEFLAG(HWPoison, hwpoison, PF_ANY)
 661TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
 662#define __PG_HWPOISON (1UL << PG_hwpoison)
 663#else
 664PAGEFLAG_FALSE(HWPoison, hwpoison)
 665#define __PG_HWPOISON 0
 666#endif
 667
 668#ifdef CONFIG_PAGE_IDLE_FLAG
 669#ifdef CONFIG_64BIT
 670FOLIO_TEST_FLAG(young, FOLIO_HEAD_PAGE)
 671FOLIO_SET_FLAG(young, FOLIO_HEAD_PAGE)
 672FOLIO_TEST_CLEAR_FLAG(young, FOLIO_HEAD_PAGE)
 673FOLIO_FLAG(idle, FOLIO_HEAD_PAGE)
 674#endif
 675/* See page_idle.h for !64BIT workaround */
 676#else /* !CONFIG_PAGE_IDLE_FLAG */
 677FOLIO_FLAG_FALSE(young)
 678FOLIO_TEST_CLEAR_FLAG_FALSE(young)
 679FOLIO_FLAG_FALSE(idle)
 680#endif
 681
 682/*
 683 * PageReported() is used to track reported free pages within the Buddy
 684 * allocator. We can use the non-atomic version of the test and set
 685 * operations as both should be shielded with the zone lock to prevent
 686 * any possible races on the setting or clearing of the bit.
 687 */
 688__PAGEFLAG(Reported, reported, PF_NO_COMPOUND)
 689
 690#ifdef CONFIG_MEMORY_HOTPLUG
 691PAGEFLAG(VmemmapSelfHosted, vmemmap_self_hosted, PF_ANY)
 692#else
 693PAGEFLAG_FALSE(VmemmapSelfHosted, vmemmap_self_hosted)
 694#endif
 695
 696/*
 697 * On an anonymous folio mapped into a user virtual memory area,
 698 * folio->mapping points to its anon_vma, not to a struct address_space;
 699 * with the FOLIO_MAPPING_ANON bit set to distinguish it.  See rmap.h.
 700 *
 701 * On an anonymous folio in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
 702 * the FOLIO_MAPPING_ANON_KSM bit may be set along with the FOLIO_MAPPING_ANON
 703 * bit; and then folio->mapping points, not to an anon_vma, but to a private
 704 * structure which KSM associates with that merged folio.  See ksm.h.
 705 *
 706 * Please note that, confusingly, "folio_mapping" refers to the inode
 707 * address_space which maps the folio from disk; whereas "folio_mapped"
 708 * refers to user virtual address space into which the folio is mapped.
 709 *
 710 * For slab pages, since slab reuses the bits in struct page to store its
 711 * internal states, the folio->mapping does not exist as such, nor do
 712 * these flags below.  So in order to avoid testing non-existent bits,
 713 * please make sure that folio_test_slab(folio) actually evaluates to
 714 * false before calling the following functions (e.g., folio_test_anon).
 715 * See mm/slab.h.
 716 */
 717#define FOLIO_MAPPING_ANON	0x1
 718#define FOLIO_MAPPING_ANON_KSM	0x2
 719#define FOLIO_MAPPING_KSM	(FOLIO_MAPPING_ANON | FOLIO_MAPPING_ANON_KSM)
 720#define FOLIO_MAPPING_FLAGS	(FOLIO_MAPPING_ANON | FOLIO_MAPPING_ANON_KSM)
 721
 722static __always_inline bool folio_test_anon(const struct folio *folio)
 723{
 724	return ((unsigned long)folio->mapping & FOLIO_MAPPING_ANON) != 0;
 725}
 726
 727static __always_inline bool PageAnonNotKsm(const struct page *page)
 728{
 729	unsigned long flags = (unsigned long)page_folio(page)->mapping;
 730
 731	return (flags & FOLIO_MAPPING_FLAGS) == FOLIO_MAPPING_ANON;
 732}
 733
 734static __always_inline bool PageAnon(const struct page *page)
 735{
 736	return folio_test_anon(page_folio(page));
 737}
 738#ifdef CONFIG_KSM
 739/*
 740 * A KSM page is one of those write-protected "shared pages" or "merged pages"
 741 * which KSM maps into multiple mms, wherever identical anonymous page content
 742 * is found in VM_MERGEABLE vmas.  It's a PageAnon page, pointing not to any
 743 * anon_vma, but to that page's node of the stable tree.
 744 */
 745static __always_inline bool folio_test_ksm(const struct folio *folio)
 746{
 747	return ((unsigned long)folio->mapping & FOLIO_MAPPING_FLAGS) ==
 748				FOLIO_MAPPING_KSM;
 749}
 750#else
 751FOLIO_TEST_FLAG_FALSE(ksm)
 752#endif
 753
 754u64 stable_page_flags(const struct page *page);
 755
 756/**
 757 * folio_xor_flags_has_waiters - Change some folio flags.
 758 * @folio: The folio.
 759 * @mask: Bits set in this word will be changed.
 760 *
 761 * This must only be used for flags which are changed with the folio
 762 * lock held.  For example, it is unsafe to use for PG_dirty as that
 763 * can be set without the folio lock held.  It can also only be used
 764 * on flags which are in the range 0-6 as some of the implementations
 765 * only affect those bits.
 766 *
 767 * Return: Whether there are tasks waiting on the folio.
 768 */
 769static inline bool folio_xor_flags_has_waiters(struct folio *folio,
 770		unsigned long mask)
 771{
 772	return xor_unlock_is_negative_byte(mask, folio_flags(folio, 0));
 773}
 774
 775/**
 776 * folio_test_uptodate - Is this folio up to date?
 777 * @folio: The folio.
 778 *
 779 * The uptodate flag is set on a folio when every byte in the folio is
 780 * at least as new as the corresponding bytes on storage.  Anonymous
 781 * and CoW folios are always uptodate.  If the folio is not uptodate,
 782 * some of the bytes in it may be; see the is_partially_uptodate()
 783 * address_space operation.
 784 */
 785static inline bool folio_test_uptodate(const struct folio *folio)
 786{
 787	bool ret = test_bit(PG_uptodate, const_folio_flags(folio, 0));
 788	/*
 789	 * Must ensure that the data we read out of the folio is loaded
 790	 * _after_ we've loaded folio->flags to check the uptodate bit.
 791	 * We can skip the barrier if the folio is not uptodate, because
 792	 * we wouldn't be reading anything from it.
 793	 *
 794	 * See folio_mark_uptodate() for the other side of the story.
 795	 */
 796	if (ret)
 797		smp_rmb();
 798
 799	return ret;
 800}
 801
 802static inline bool PageUptodate(const struct page *page)
 803{
 804	return folio_test_uptodate(page_folio(page));
 805}
 806
 807static __always_inline void __folio_mark_uptodate(struct folio *folio)
 808{
 809	smp_wmb();
 810	__set_bit(PG_uptodate, folio_flags(folio, 0));
 811}
 812
 813static __always_inline void folio_mark_uptodate(struct folio *folio)
 814{
 815	/*
 816	 * Memory barrier must be issued before setting the PG_uptodate bit,
 817	 * so that all previous stores issued in order to bring the folio
 818	 * uptodate are actually visible before folio_test_uptodate becomes true.
 819	 */
 820	smp_wmb();
 821	set_bit(PG_uptodate, folio_flags(folio, 0));
 822}
 823
 824static __always_inline void __SetPageUptodate(struct page *page)
 825{
 826	__folio_mark_uptodate((struct folio *)page);
 827}
 828
 829static __always_inline void SetPageUptodate(struct page *page)
 830{
 831	folio_mark_uptodate((struct folio *)page);
 832}
 833
 834CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)
 835
 836void __folio_start_writeback(struct folio *folio, bool keep_write);
 837void set_page_writeback(struct page *page);
 838
 839#define folio_start_writeback(folio)			\
 840	__folio_start_writeback(folio, false)
 841
 842static __always_inline bool folio_test_head(const struct folio *folio)
 843{
 844	return test_bit(PG_head, const_folio_flags(folio, FOLIO_PF_ANY));
 845}
 846
 847static __always_inline int PageHead(const struct page *page)
 848{
 849	PF_POISONED_CHECK(page);
 850	return test_bit(PG_head, &page->flags.f) && !page_is_fake_head(page);
 851}
 852
 853__SETPAGEFLAG(Head, head, PF_ANY)
 854__CLEARPAGEFLAG(Head, head, PF_ANY)
 855CLEARPAGEFLAG(Head, head, PF_ANY)
 856
 857/**
 858 * folio_test_large() - Does this folio contain more than one page?
 859 * @folio: The folio to test.
 860 *
 861 * Return: True if the folio is larger than one page.
 862 */
 863static inline bool folio_test_large(const struct folio *folio)
 864{
 865	return folio_test_head(folio);
 866}
 867
 868static __always_inline void set_compound_head(struct page *page, struct page *head)
 869{
 870	WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
 871}
 872
 873static __always_inline void clear_compound_head(struct page *page)
 874{
 875	WRITE_ONCE(page->compound_head, 0);
 876}
 877
 878#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 879static inline void ClearPageCompound(struct page *page)
 880{
 881	BUG_ON(!PageHead(page));
 882	ClearPageHead(page);
 883}
 884FOLIO_FLAG(large_rmappable, FOLIO_SECOND_PAGE)
 885FOLIO_FLAG(partially_mapped, FOLIO_SECOND_PAGE)
 886#else
 887FOLIO_FLAG_FALSE(large_rmappable)
 888FOLIO_FLAG_FALSE(partially_mapped)
 889#endif
 890
 891#define PG_head_mask ((1UL << PG_head))
 892
 893#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 894/*
 895 * PageTransCompound returns true for both transparent huge pages
 896 * and hugetlbfs pages, so it should only be called when it's known
 897 * that hugetlbfs pages aren't involved.
 898 */
 899static inline int PageTransCompound(const struct page *page)
 900{
 901	return PageCompound(page);
 902}
 903#else
 904TESTPAGEFLAG_FALSE(TransCompound, transcompound)
 905#endif
 906
 907#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 908/*
 909 * PageHasHWPoisoned indicates that at least one subpage is hwpoisoned in the
 910 * compound page.
 911 *
 912 * This flag is set by hwpoison handler.  Cleared by THP split or free page.
 913 */
 914FOLIO_FLAG(has_hwpoisoned, FOLIO_SECOND_PAGE)
 915#else
 916FOLIO_FLAG_FALSE(has_hwpoisoned)
 917#endif
 918
 919/*
 920 * For pages that do not use mapcount, page_type may be used.
 921 * The low 24 bits of pagetype may be used for your own purposes, as long
 922 * as you are careful to not affect the top 8 bits.  The low bits of
 923 * pagetype will be overwritten when you clear the page_type from the page.
 924 */
 925enum pagetype {
 926	/* 0x00-0x7f are positive numbers, ie mapcount */
 927	/* Reserve 0x80-0xef for mapcount overflow. */
 928	PGTY_buddy		= 0xf0,
 929	PGTY_offline		= 0xf1,
 930	PGTY_table		= 0xf2,
 931	PGTY_guard		= 0xf3,
 932	PGTY_hugetlb		= 0xf4,
 933	PGTY_slab		= 0xf5,
 934	PGTY_zsmalloc		= 0xf6,
 935	PGTY_unaccepted		= 0xf7,
 936	PGTY_large_kmalloc	= 0xf8,
 937
 938	PGTY_mapcount_underflow = 0xff
 939};
 940
 941static inline bool page_type_has_type(int page_type)
 942{
 943	return page_type < (PGTY_mapcount_underflow << 24);
 944}
 945
 946/* This takes a mapcount which is one more than page->_mapcount */
 947static inline bool page_mapcount_is_type(unsigned int mapcount)
 948{
 949	return page_type_has_type(mapcount - 1);
 950}
 951
 952static inline bool page_has_type(const struct page *page)
 953{
 954	return page_type_has_type(data_race(page->page_type));
 955}
 956
 957#define FOLIO_TYPE_OPS(lname, fname)					\
 958static __always_inline bool folio_test_##fname(const struct folio *folio) \
 959{									\
 960	return data_race(folio->page.page_type >> 24) == PGTY_##lname;	\
 961}									\
 962static __always_inline void __folio_set_##fname(struct folio *folio)	\
 963{									\
 964	if (folio_test_##fname(folio))					\
 965		return;							\
 966	VM_BUG_ON_FOLIO(data_race(folio->page.page_type) != UINT_MAX,	\
 967			folio);						\
 968	folio->page.page_type = (unsigned int)PGTY_##lname << 24;	\
 969}									\
 970static __always_inline void __folio_clear_##fname(struct folio *folio)	\
 971{									\
 972	if (folio->page.page_type == UINT_MAX)				\
 973		return;							\
 974	VM_BUG_ON_FOLIO(!folio_test_##fname(folio), folio);		\
 975	folio->page.page_type = UINT_MAX;				\
 976}
 977
 978#define PAGE_TYPE_OPS(uname, lname, fname)				\
 979FOLIO_TYPE_OPS(lname, fname)						\
 980static __always_inline int Page##uname(const struct page *page)		\
 981{									\
 982	return data_race(page->page_type >> 24) == PGTY_##lname;	\
 983}									\
 984static __always_inline void __SetPage##uname(struct page *page)		\
 985{									\
 986	if (Page##uname(page))						\
 987		return;							\
 988	VM_BUG_ON_PAGE(data_race(page->page_type) != UINT_MAX, page);	\
 989	page->page_type = (unsigned int)PGTY_##lname << 24;		\
 990}									\
 991static __always_inline void __ClearPage##uname(struct page *page)	\
 992{									\
 993	if (page->page_type == UINT_MAX)				\
 994		return;							\
 995	VM_BUG_ON_PAGE(!Page##uname(page), page);			\
 996	page->page_type = UINT_MAX;					\
 997}
 998
 999/*
1000 * PageBuddy() indicates that the page is free and in the buddy system
1001 * (see mm/page_alloc.c).
1002 */
1003PAGE_TYPE_OPS(Buddy, buddy, buddy)
1004
1005/*
1006 * PageOffline() indicates that the page is logically offline although the
1007 * containing section is online. (e.g. inflated in a balloon driver or
1008 * not onlined when onlining the section).
1009 * The content of these pages is effectively stale. Such pages should not
1010 * be touched (read/write/dump/save) except by their owner.
1011 *
1012 * When a memory block gets onlined, all pages are initialized with a
1013 * refcount of 1 and PageOffline(). generic_online_page() will
1014 * take care of clearing PageOffline().
1015 *
1016 * If a driver wants to allow to offline unmovable PageOffline() pages without
1017 * putting them back to the buddy, it can do so via the memory notifier by
1018 * decrementing the reference count in MEM_GOING_OFFLINE and incrementing the
1019 * reference count in MEM_CANCEL_OFFLINE. When offlining, the PageOffline()
1020 * pages (now with a reference count of zero) are treated like free (unmanaged)
1021 * pages, allowing the containing memory block to get offlined. A driver that
1022 * relies on this feature is aware that re-onlining the memory block will
1023 * require not giving them to the buddy via generic_online_page().
1024 *
1025 * Memory offlining code will not adjust the managed page count for any
1026 * PageOffline() pages, treating them like they were never exposed to the
1027 * buddy using generic_online_page().
1028 *
1029 * There are drivers that mark a page PageOffline() and expect there won't be
1030 * any further access to page content. PFN walkers that read content of random
1031 * pages should check PageOffline() and synchronize with such drivers using
1032 * page_offline_freeze()/page_offline_thaw().
1033 */
1034PAGE_TYPE_OPS(Offline, offline, offline)
1035
1036extern void page_offline_freeze(void);
1037extern void page_offline_thaw(void);
1038extern void page_offline_begin(void);
1039extern void page_offline_end(void);
1040
1041/*
1042 * Marks pages in use as page tables.
1043 */
1044PAGE_TYPE_OPS(Table, table, pgtable)
1045
1046/*
1047 * Marks guardpages used with debug_pagealloc.
1048 */
1049PAGE_TYPE_OPS(Guard, guard, guard)
1050
1051PAGE_TYPE_OPS(Slab, slab, slab)
1052
1053#ifdef CONFIG_HUGETLB_PAGE
1054FOLIO_TYPE_OPS(hugetlb, hugetlb)
1055#else
1056FOLIO_TEST_FLAG_FALSE(hugetlb)
1057#endif
1058
1059PAGE_TYPE_OPS(Zsmalloc, zsmalloc, zsmalloc)
1060
1061/*
1062 * Mark pages that has to be accepted before touched for the first time.
1063 *
1064 * Serialized with zone lock.
1065 */
1066PAGE_TYPE_OPS(Unaccepted, unaccepted, unaccepted)
1067PAGE_TYPE_OPS(LargeKmalloc, large_kmalloc, large_kmalloc)
1068
1069/**
1070 * PageHuge - Determine if the page belongs to hugetlbfs
1071 * @page: The page to test.
1072 *
1073 * Context: Any context.
1074 * Return: True for hugetlbfs pages, false for anon pages or pages
1075 * belonging to other filesystems.
1076 */
1077static inline bool PageHuge(const struct page *page)
1078{
1079	return folio_test_hugetlb(page_folio(page));
1080}
1081
1082/*
1083 * Check if a page is currently marked HWPoisoned. Note that this check is
1084 * best effort only and inherently racy: there is no way to synchronize with
1085 * failing hardware.
1086 */
1087static inline bool is_page_hwpoison(const struct page *page)
1088{
1089	const struct folio *folio;
1090
1091	if (PageHWPoison(page))
1092		return true;
1093	folio = page_folio(page);
1094	return folio_test_hugetlb(folio) && PageHWPoison(&folio->page);
1095}
1096
1097static inline bool folio_contain_hwpoisoned_page(struct folio *folio)
1098{
1099	return folio_test_hwpoison(folio) ||
1100	    (folio_test_large(folio) && folio_test_has_hwpoisoned(folio));
1101}
1102
1103bool is_free_buddy_page(const struct page *page);
1104
1105#ifdef CONFIG_MIGRATION
1106/*
1107 * This page is migratable through movable_ops (for selected typed pages
1108 * only).
1109 *
1110 * Page migration of such pages might fail, for example, if the page is
1111 * already isolated by somebody else, or if the page is about to get freed.
1112 *
1113 * While a subsystem might set selected typed pages that support page migration
1114 * as being movable through movable_ops, it must never clear this flag.
1115 *
1116 * This flag is only cleared when the page is freed back to the buddy.
1117 *
1118 * Only selected page types support this flag (see page_movable_ops()) and
1119 * the flag might be used in other context for other pages. Always use
1120 * page_has_movable_ops() instead.
1121 */
1122TESTPAGEFLAG(MovableOps, movable_ops, PF_NO_TAIL);
1123SETPAGEFLAG(MovableOps, movable_ops, PF_NO_TAIL);
1124/*
1125 * A movable_ops page has this flag set while it is isolated for migration.
1126 * This flag primarily protects against concurrent migration attempts.
1127 *
1128 * Once migration ended (success or failure), the flag is cleared. The
1129 * flag is managed by the migration core.
1130 */
1131PAGEFLAG(MovableOpsIsolated, movable_ops_isolated, PF_NO_TAIL);
1132#else /* !CONFIG_MIGRATION */
1133TESTPAGEFLAG_FALSE(MovableOps, movable_ops);
1134SETPAGEFLAG_NOOP(MovableOps, movable_ops);
1135PAGEFLAG_FALSE(MovableOpsIsolated, movable_ops_isolated);
1136#endif /* CONFIG_MIGRATION */
1137
1138/**
1139 * page_has_movable_ops - test for a movable_ops page
1140 * @page: The page to test.
1141 *
1142 * Test whether this is a movable_ops page. Such pages will stay that
1143 * way until freed.
1144 *
1145 * Returns true if this is a movable_ops page, otherwise false.
1146 */
1147static inline bool page_has_movable_ops(const struct page *page)
1148{
1149	return PageMovableOps(page) &&
1150	       (PageOffline(page) || PageZsmalloc(page));
1151}
1152
1153static __always_inline int PageAnonExclusive(const struct page *page)
1154{
1155	VM_BUG_ON_PGFLAGS(!PageAnon(page), page);
1156	/*
1157	 * HugeTLB stores this information on the head page; THP keeps it per
1158	 * page
1159	 */
1160	if (PageHuge(page))
1161		page = compound_head(page);
1162	return test_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags.f);
1163}
1164
1165static __always_inline void SetPageAnonExclusive(struct page *page)
1166{
1167	VM_BUG_ON_PGFLAGS(!PageAnonNotKsm(page), page);
1168	VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
1169	set_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags.f);
1170}
1171
1172static __always_inline void ClearPageAnonExclusive(struct page *page)
1173{
1174	VM_BUG_ON_PGFLAGS(!PageAnonNotKsm(page), page);
1175	VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
1176	clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags.f);
1177}
1178
1179static __always_inline void __ClearPageAnonExclusive(struct page *page)
1180{
1181	VM_BUG_ON_PGFLAGS(!PageAnon(page), page);
1182	VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
1183	__clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags.f);
1184}
1185
1186#ifdef CONFIG_MMU
1187#define __PG_MLOCKED		(1UL << PG_mlocked)
1188#else
1189#define __PG_MLOCKED		0
1190#endif
1191
1192/*
1193 * Flags checked when a page is freed.  Pages being freed should not have
1194 * these flags set.  If they are, there is a problem.
1195 */
1196#define PAGE_FLAGS_CHECK_AT_FREE				\
1197	(1UL << PG_lru		| 1UL << PG_locked	|	\
1198	 1UL << PG_private	| 1UL << PG_private_2	|	\
1199	 1UL << PG_writeback	| 1UL << PG_reserved	|	\
1200	 1UL << PG_active 	|				\
1201	 1UL << PG_unevictable	| __PG_MLOCKED | LRU_GEN_MASK)
1202
1203/*
1204 * Flags checked when a page is prepped for return by the page allocator.
1205 * Pages being prepped should not have these flags set.  If they are set,
1206 * there has been a kernel bug or struct page corruption.
1207 *
1208 * __PG_HWPOISON is exceptional because it needs to be kept beyond page's
1209 * alloc-free cycle to prevent from reusing the page.
1210 */
1211#define PAGE_FLAGS_CHECK_AT_PREP	\
1212	((PAGEFLAGS_MASK & ~__PG_HWPOISON) | LRU_GEN_MASK | LRU_REFS_MASK)
1213
1214/*
1215 * Flags stored in the second page of a compound page.  They may overlap
1216 * the CHECK_AT_FREE flags above, so need to be cleared.
1217 */
1218#define PAGE_FLAGS_SECOND						\
1219	(0xffUL /* order */		| 1UL << PG_has_hwpoisoned |	\
1220	 1UL << PG_large_rmappable	| 1UL << PG_partially_mapped)
1221
1222#define PAGE_FLAGS_PRIVATE				\
1223	(1UL << PG_private | 1UL << PG_private_2)
1224/**
1225 * folio_has_private - Determine if folio has private stuff
1226 * @folio: The folio to be checked
1227 *
1228 * Determine if a folio has private stuff, indicating that release routines
1229 * should be invoked upon it.
1230 */
1231static inline int folio_has_private(const struct folio *folio)
1232{
1233	return !!(folio->flags.f & PAGE_FLAGS_PRIVATE);
1234}
1235
1236#undef PF_ANY
1237#undef PF_HEAD
1238#undef PF_NO_TAIL
1239#undef PF_NO_COMPOUND
1240#undef PF_SECOND
1241#endif /* !__GENERATING_BOUNDS_H */
1242
1243#endif	/* PAGE_FLAGS_H */