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 not added to the page allocator when onlining a section because 34 * they were excluded via the online_page_callback() or because they are 35 * PG_hwpoison. 36 * - Pages allocated in the context of kexec/kdump (loaded kernel image, 37 * control pages, vmcoreinfo) 38 * - MMIO/DMA pages. Some architectures don't allow to ioremap pages that are 39 * not marked PG_reserved (as they might be in use by somebody else who does 40 * not respect the caching strategy). 41 * - Pages part of an offline section (struct pages of offline sections should 42 * not be trusted as they will be initialized when first onlined). 43 * - MCA pages on ia64 44 * - Pages holding CPU notes for POWER Firmware Assisted Dump 45 * - Device memory (e.g. PMEM, DAX, HMM) 46 * Some PG_reserved pages will be excluded from the hibernation image. 47 * PG_reserved does in general not hinder anybody from dumping or swapping 48 * and is no longer required for remap_pfn_range(). ioremap might require it. 49 * Consequently, PG_reserved for a page mapped into user space can indicate 50 * the zero page, the vDSO, MMIO pages or device memory. 51 * 52 * The PG_private bitflag is set on pagecache pages if they contain filesystem 53 * specific data (which is normally at page->private). It can be used by 54 * private allocations for its own usage. 55 * 56 * During initiation of disk I/O, PG_locked is set. This bit is set before I/O 57 * and cleared when writeback _starts_ or when read _completes_. PG_writeback 58 * is set before writeback starts and cleared when it finishes. 59 * 60 * PG_locked also pins a page in pagecache, and blocks truncation of the file 61 * while it is held. 62 * 63 * page_waitqueue(page) is a wait queue of all tasks waiting for the page 64 * to become unlocked. 65 * 66 * PG_swapbacked is set when a page uses swap as a backing storage. This are 67 * usually PageAnon or shmem pages but please note that even anonymous pages 68 * might lose their PG_swapbacked flag when they simply can be dropped (e.g. as 69 * a result of MADV_FREE). 70 * 71 * PG_referenced, PG_reclaim are used for page reclaim for anonymous and 72 * file-backed pagecache (see mm/vmscan.c). 73 * 74 * PG_error is set to indicate that an I/O error occurred on this page. 75 * 76 * PG_arch_1 is an architecture specific page state bit. The generic code 77 * guarantees that this bit is cleared for a page when it first is entered into 78 * the page cache. 79 * 80 * PG_hwpoison indicates that a page got corrupted in hardware and contains 81 * data with incorrect ECC bits that triggered a machine check. Accessing is 82 * not safe since it may cause another machine check. Don't touch! 83 */ 84 85 /* 86 * Don't use the pageflags directly. Use the PageFoo macros. 87 * 88 * The page flags field is split into two parts, the main flags area 89 * which extends from the low bits upwards, and the fields area which 90 * extends from the high bits downwards. 91 * 92 * | FIELD | ... | FLAGS | 93 * N-1 ^ 0 94 * (NR_PAGEFLAGS) 95 * 96 * The fields area is reserved for fields mapping zone, node (for NUMA) and 97 * SPARSEMEM section (for variants of SPARSEMEM that require section ids like 98 * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP). 99 */ 100 enum pageflags { 101 PG_locked, /* Page is locked. Don't touch. */ 102 PG_referenced, 103 PG_uptodate, 104 PG_dirty, 105 PG_lru, 106 PG_active, 107 PG_workingset, 108 PG_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */ 109 PG_error, 110 PG_slab, 111 PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/ 112 PG_arch_1, 113 PG_reserved, 114 PG_private, /* If pagecache, has fs-private data */ 115 PG_private_2, /* If pagecache, has fs aux data */ 116 PG_writeback, /* Page is under writeback */ 117 PG_head, /* A head page */ 118 PG_mappedtodisk, /* Has blocks allocated on-disk */ 119 PG_reclaim, /* To be reclaimed asap */ 120 PG_swapbacked, /* Page is backed by RAM/swap */ 121 PG_unevictable, /* Page is "unevictable" */ 122 #ifdef CONFIG_MMU 123 PG_mlocked, /* Page is vma mlocked */ 124 #endif 125 #ifdef CONFIG_ARCH_USES_PG_UNCACHED 126 PG_uncached, /* Page has been mapped as uncached */ 127 #endif 128 #ifdef CONFIG_MEMORY_FAILURE 129 PG_hwpoison, /* hardware poisoned page. Don't touch */ 130 #endif 131 #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT) 132 PG_young, 133 PG_idle, 134 #endif 135 #ifdef CONFIG_64BIT 136 PG_arch_2, 137 #endif 138 #ifdef CONFIG_KASAN_HW_TAGS 139 PG_skip_kasan_poison, 140 #endif 141 __NR_PAGEFLAGS, 142 143 PG_readahead = PG_reclaim, 144 145 /* 146 * Depending on the way an anonymous folio can be mapped into a page 147 * table (e.g., single PMD/PUD/CONT of the head page vs. PTE-mapped 148 * THP), PG_anon_exclusive may be set only for the head page or for 149 * tail pages of an anonymous folio. For now, we only expect it to be 150 * set on tail pages for PTE-mapped THP. 151 */ 152 PG_anon_exclusive = PG_mappedtodisk, 153 154 /* Filesystems */ 155 PG_checked = PG_owner_priv_1, 156 157 /* SwapBacked */ 158 PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */ 159 160 /* Two page bits are conscripted by FS-Cache to maintain local caching 161 * state. These bits are set on pages belonging to the netfs's inodes 162 * when those inodes are being locally cached. 163 */ 164 PG_fscache = PG_private_2, /* page backed by cache */ 165 166 /* XEN */ 167 /* Pinned in Xen as a read-only pagetable page. */ 168 PG_pinned = PG_owner_priv_1, 169 /* Pinned as part of domain save (see xen_mm_pin_all()). */ 170 PG_savepinned = PG_dirty, 171 /* Has a grant mapping of another (foreign) domain's page. */ 172 PG_foreign = PG_owner_priv_1, 173 /* Remapped by swiotlb-xen. */ 174 PG_xen_remapped = PG_owner_priv_1, 175 176 /* SLOB */ 177 PG_slob_free = PG_private, 178 179 /* Compound pages. Stored in first tail page's flags */ 180 PG_double_map = PG_workingset, 181 182 #ifdef CONFIG_MEMORY_FAILURE 183 /* 184 * Compound pages. Stored in first tail page's flags. 185 * Indicates that at least one subpage is hwpoisoned in the 186 * THP. 187 */ 188 PG_has_hwpoisoned = PG_error, 189 #endif 190 191 /* non-lru isolated movable page */ 192 PG_isolated = PG_reclaim, 193 194 /* Only valid for buddy pages. Used to track pages that are reported */ 195 PG_reported = PG_uptodate, 196 197 #ifdef CONFIG_MEMORY_HOTPLUG 198 /* For self-hosted memmap pages */ 199 PG_vmemmap_self_hosted = PG_owner_priv_1, 200 #endif 201 }; 202 203 #define PAGEFLAGS_MASK ((1UL << NR_PAGEFLAGS) - 1) 204 205 #ifndef __GENERATING_BOUNDS_H 206 207 #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP 208 DECLARE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key); 209 210 /* 211 * Return the real head page struct iff the @page is a fake head page, otherwise 212 * return the @page itself. See Documentation/mm/vmemmap_dedup.rst. 213 */ 214 static __always_inline const struct page *page_fixed_fake_head(const struct page *page) 215 { 216 if (!static_branch_unlikely(&hugetlb_optimize_vmemmap_key)) 217 return page; 218 219 /* 220 * Only addresses aligned with PAGE_SIZE of struct page may be fake head 221 * struct page. The alignment check aims to avoid access the fields ( 222 * e.g. compound_head) of the @page[1]. It can avoid touch a (possibly) 223 * cold cacheline in some cases. 224 */ 225 if (IS_ALIGNED((unsigned long)page, PAGE_SIZE) && 226 test_bit(PG_head, &page->flags)) { 227 /* 228 * We can safely access the field of the @page[1] with PG_head 229 * because the @page is a compound page composed with at least 230 * two contiguous pages. 231 */ 232 unsigned long head = READ_ONCE(page[1].compound_head); 233 234 if (likely(head & 1)) 235 return (const struct page *)(head - 1); 236 } 237 return page; 238 } 239 #else 240 static inline const struct page *page_fixed_fake_head(const struct page *page) 241 { 242 return page; 243 } 244 #endif 245 246 static __always_inline int page_is_fake_head(struct page *page) 247 { 248 return page_fixed_fake_head(page) != page; 249 } 250 251 static inline unsigned long _compound_head(const struct page *page) 252 { 253 unsigned long head = READ_ONCE(page->compound_head); 254 255 if (unlikely(head & 1)) 256 return head - 1; 257 return (unsigned long)page_fixed_fake_head(page); 258 } 259 260 #define compound_head(page) ((typeof(page))_compound_head(page)) 261 262 /** 263 * page_folio - Converts from page to folio. 264 * @p: The page. 265 * 266 * Every page is part of a folio. This function cannot be called on a 267 * NULL pointer. 268 * 269 * Context: No reference, nor lock is required on @page. If the caller 270 * does not hold a reference, this call may race with a folio split, so 271 * it should re-check the folio still contains this page after gaining 272 * a reference on the folio. 273 * Return: The folio which contains this page. 274 */ 275 #define page_folio(p) (_Generic((p), \ 276 const struct page *: (const struct folio *)_compound_head(p), \ 277 struct page *: (struct folio *)_compound_head(p))) 278 279 /** 280 * folio_page - Return a page from a folio. 281 * @folio: The folio. 282 * @n: The page number to return. 283 * 284 * @n is relative to the start of the folio. This function does not 285 * check that the page number lies within @folio; the caller is presumed 286 * to have a reference to the page. 287 */ 288 #define folio_page(folio, n) nth_page(&(folio)->page, n) 289 290 static __always_inline int PageTail(struct page *page) 291 { 292 return READ_ONCE(page->compound_head) & 1 || page_is_fake_head(page); 293 } 294 295 static __always_inline int PageCompound(struct page *page) 296 { 297 return test_bit(PG_head, &page->flags) || 298 READ_ONCE(page->compound_head) & 1; 299 } 300 301 #define PAGE_POISON_PATTERN -1l 302 static inline int PagePoisoned(const struct page *page) 303 { 304 return READ_ONCE(page->flags) == PAGE_POISON_PATTERN; 305 } 306 307 #ifdef CONFIG_DEBUG_VM 308 void page_init_poison(struct page *page, size_t size); 309 #else 310 static inline void page_init_poison(struct page *page, size_t size) 311 { 312 } 313 #endif 314 315 static unsigned long *folio_flags(struct folio *folio, unsigned n) 316 { 317 struct page *page = &folio->page; 318 319 VM_BUG_ON_PGFLAGS(PageTail(page), page); 320 VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page); 321 return &page[n].flags; 322 } 323 324 /* 325 * Page flags policies wrt compound pages 326 * 327 * PF_POISONED_CHECK 328 * check if this struct page poisoned/uninitialized 329 * 330 * PF_ANY: 331 * the page flag is relevant for small, head and tail pages. 332 * 333 * PF_HEAD: 334 * for compound page all operations related to the page flag applied to 335 * head page. 336 * 337 * PF_ONLY_HEAD: 338 * for compound page, callers only ever operate on the head page. 339 * 340 * PF_NO_TAIL: 341 * modifications of the page flag must be done on small or head pages, 342 * checks can be done on tail pages too. 343 * 344 * PF_NO_COMPOUND: 345 * the page flag is not relevant for compound pages. 346 * 347 * PF_SECOND: 348 * the page flag is stored in the first tail page. 349 */ 350 #define PF_POISONED_CHECK(page) ({ \ 351 VM_BUG_ON_PGFLAGS(PagePoisoned(page), page); \ 352 page; }) 353 #define PF_ANY(page, enforce) PF_POISONED_CHECK(page) 354 #define PF_HEAD(page, enforce) PF_POISONED_CHECK(compound_head(page)) 355 #define PF_ONLY_HEAD(page, enforce) ({ \ 356 VM_BUG_ON_PGFLAGS(PageTail(page), page); \ 357 PF_POISONED_CHECK(page); }) 358 #define PF_NO_TAIL(page, enforce) ({ \ 359 VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \ 360 PF_POISONED_CHECK(compound_head(page)); }) 361 #define PF_NO_COMPOUND(page, enforce) ({ \ 362 VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \ 363 PF_POISONED_CHECK(page); }) 364 #define PF_SECOND(page, enforce) ({ \ 365 VM_BUG_ON_PGFLAGS(!PageHead(page), page); \ 366 PF_POISONED_CHECK(&page[1]); }) 367 368 /* Which page is the flag stored in */ 369 #define FOLIO_PF_ANY 0 370 #define FOLIO_PF_HEAD 0 371 #define FOLIO_PF_ONLY_HEAD 0 372 #define FOLIO_PF_NO_TAIL 0 373 #define FOLIO_PF_NO_COMPOUND 0 374 #define FOLIO_PF_SECOND 1 375 376 /* 377 * Macros to create function definitions for page flags 378 */ 379 #define TESTPAGEFLAG(uname, lname, policy) \ 380 static __always_inline bool folio_test_##lname(struct folio *folio) \ 381 { return test_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \ 382 static __always_inline int Page##uname(struct page *page) \ 383 { return test_bit(PG_##lname, &policy(page, 0)->flags); } 384 385 #define SETPAGEFLAG(uname, lname, policy) \ 386 static __always_inline \ 387 void folio_set_##lname(struct folio *folio) \ 388 { set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \ 389 static __always_inline void SetPage##uname(struct page *page) \ 390 { set_bit(PG_##lname, &policy(page, 1)->flags); } 391 392 #define CLEARPAGEFLAG(uname, lname, policy) \ 393 static __always_inline \ 394 void folio_clear_##lname(struct folio *folio) \ 395 { clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \ 396 static __always_inline void ClearPage##uname(struct page *page) \ 397 { clear_bit(PG_##lname, &policy(page, 1)->flags); } 398 399 #define __SETPAGEFLAG(uname, lname, policy) \ 400 static __always_inline \ 401 void __folio_set_##lname(struct folio *folio) \ 402 { __set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \ 403 static __always_inline void __SetPage##uname(struct page *page) \ 404 { __set_bit(PG_##lname, &policy(page, 1)->flags); } 405 406 #define __CLEARPAGEFLAG(uname, lname, policy) \ 407 static __always_inline \ 408 void __folio_clear_##lname(struct folio *folio) \ 409 { __clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \ 410 static __always_inline void __ClearPage##uname(struct page *page) \ 411 { __clear_bit(PG_##lname, &policy(page, 1)->flags); } 412 413 #define TESTSETFLAG(uname, lname, policy) \ 414 static __always_inline \ 415 bool folio_test_set_##lname(struct folio *folio) \ 416 { return test_and_set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \ 417 static __always_inline int TestSetPage##uname(struct page *page) \ 418 { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); } 419 420 #define TESTCLEARFLAG(uname, lname, policy) \ 421 static __always_inline \ 422 bool folio_test_clear_##lname(struct folio *folio) \ 423 { return test_and_clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \ 424 static __always_inline int TestClearPage##uname(struct page *page) \ 425 { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); } 426 427 #define PAGEFLAG(uname, lname, policy) \ 428 TESTPAGEFLAG(uname, lname, policy) \ 429 SETPAGEFLAG(uname, lname, policy) \ 430 CLEARPAGEFLAG(uname, lname, policy) 431 432 #define __PAGEFLAG(uname, lname, policy) \ 433 TESTPAGEFLAG(uname, lname, policy) \ 434 __SETPAGEFLAG(uname, lname, policy) \ 435 __CLEARPAGEFLAG(uname, lname, policy) 436 437 #define TESTSCFLAG(uname, lname, policy) \ 438 TESTSETFLAG(uname, lname, policy) \ 439 TESTCLEARFLAG(uname, lname, policy) 440 441 #define TESTPAGEFLAG_FALSE(uname, lname) \ 442 static inline bool folio_test_##lname(const struct folio *folio) { return false; } \ 443 static inline int Page##uname(const struct page *page) { return 0; } 444 445 #define SETPAGEFLAG_NOOP(uname, lname) \ 446 static inline void folio_set_##lname(struct folio *folio) { } \ 447 static inline void SetPage##uname(struct page *page) { } 448 449 #define CLEARPAGEFLAG_NOOP(uname, lname) \ 450 static inline void folio_clear_##lname(struct folio *folio) { } \ 451 static inline void ClearPage##uname(struct page *page) { } 452 453 #define __CLEARPAGEFLAG_NOOP(uname, lname) \ 454 static inline void __folio_clear_##lname(struct folio *folio) { } \ 455 static inline void __ClearPage##uname(struct page *page) { } 456 457 #define TESTSETFLAG_FALSE(uname, lname) \ 458 static inline bool folio_test_set_##lname(struct folio *folio) \ 459 { return 0; } \ 460 static inline int TestSetPage##uname(struct page *page) { return 0; } 461 462 #define TESTCLEARFLAG_FALSE(uname, lname) \ 463 static inline bool folio_test_clear_##lname(struct folio *folio) \ 464 { return 0; } \ 465 static inline int TestClearPage##uname(struct page *page) { return 0; } 466 467 #define PAGEFLAG_FALSE(uname, lname) TESTPAGEFLAG_FALSE(uname, lname) \ 468 SETPAGEFLAG_NOOP(uname, lname) CLEARPAGEFLAG_NOOP(uname, lname) 469 470 #define TESTSCFLAG_FALSE(uname, lname) \ 471 TESTSETFLAG_FALSE(uname, lname) TESTCLEARFLAG_FALSE(uname, lname) 472 473 __PAGEFLAG(Locked, locked, PF_NO_TAIL) 474 PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) 475 PAGEFLAG(Error, error, PF_NO_TAIL) TESTCLEARFLAG(Error, error, PF_NO_TAIL) 476 PAGEFLAG(Referenced, referenced, PF_HEAD) 477 TESTCLEARFLAG(Referenced, referenced, PF_HEAD) 478 __SETPAGEFLAG(Referenced, referenced, PF_HEAD) 479 PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD) 480 __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD) 481 PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD) 482 TESTCLEARFLAG(LRU, lru, PF_HEAD) 483 PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD) 484 TESTCLEARFLAG(Active, active, PF_HEAD) 485 PAGEFLAG(Workingset, workingset, PF_HEAD) 486 TESTCLEARFLAG(Workingset, workingset, PF_HEAD) 487 __PAGEFLAG(Slab, slab, PF_NO_TAIL) 488 __PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL) 489 PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */ 490 491 /* Xen */ 492 PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND) 493 TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND) 494 PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND); 495 PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND); 496 PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND) 497 TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND) 498 499 PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) 500 __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) 501 __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) 502 PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) 503 __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) 504 __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) 505 506 /* 507 * Private page markings that may be used by the filesystem that owns the page 508 * for its own purposes. 509 * - PG_private and PG_private_2 cause release_folio() and co to be invoked 510 */ 511 PAGEFLAG(Private, private, PF_ANY) 512 PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY) 513 PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY) 514 TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY) 515 516 /* 517 * Only test-and-set exist for PG_writeback. The unconditional operators are 518 * risky: they bypass page accounting. 519 */ 520 TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL) 521 TESTSCFLAG(Writeback, writeback, PF_NO_TAIL) 522 PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL) 523 524 /* PG_readahead is only used for reads; PG_reclaim is only for writes */ 525 PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL) 526 TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL) 527 PAGEFLAG(Readahead, readahead, PF_NO_COMPOUND) 528 TESTCLEARFLAG(Readahead, readahead, PF_NO_COMPOUND) 529 530 #ifdef CONFIG_HIGHMEM 531 /* 532 * Must use a macro here due to header dependency issues. page_zone() is not 533 * available at this point. 534 */ 535 #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p)) 536 #else 537 PAGEFLAG_FALSE(HighMem, highmem) 538 #endif 539 540 #ifdef CONFIG_SWAP 541 static __always_inline bool folio_test_swapcache(struct folio *folio) 542 { 543 return folio_test_swapbacked(folio) && 544 test_bit(PG_swapcache, folio_flags(folio, 0)); 545 } 546 547 static __always_inline bool PageSwapCache(struct page *page) 548 { 549 return folio_test_swapcache(page_folio(page)); 550 } 551 552 SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL) 553 CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL) 554 #else 555 PAGEFLAG_FALSE(SwapCache, swapcache) 556 #endif 557 558 PAGEFLAG(Unevictable, unevictable, PF_HEAD) 559 __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD) 560 TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD) 561 562 #ifdef CONFIG_MMU 563 PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL) 564 __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL) 565 TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL) 566 #else 567 PAGEFLAG_FALSE(Mlocked, mlocked) __CLEARPAGEFLAG_NOOP(Mlocked, mlocked) 568 TESTSCFLAG_FALSE(Mlocked, mlocked) 569 #endif 570 571 #ifdef CONFIG_ARCH_USES_PG_UNCACHED 572 PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND) 573 #else 574 PAGEFLAG_FALSE(Uncached, uncached) 575 #endif 576 577 #ifdef CONFIG_MEMORY_FAILURE 578 PAGEFLAG(HWPoison, hwpoison, PF_ANY) 579 TESTSCFLAG(HWPoison, hwpoison, PF_ANY) 580 #define __PG_HWPOISON (1UL << PG_hwpoison) 581 #define MAGIC_HWPOISON 0x48575053U /* HWPS */ 582 extern void SetPageHWPoisonTakenOff(struct page *page); 583 extern void ClearPageHWPoisonTakenOff(struct page *page); 584 extern bool take_page_off_buddy(struct page *page); 585 extern bool put_page_back_buddy(struct page *page); 586 #else 587 PAGEFLAG_FALSE(HWPoison, hwpoison) 588 #define __PG_HWPOISON 0 589 #endif 590 591 #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT) 592 TESTPAGEFLAG(Young, young, PF_ANY) 593 SETPAGEFLAG(Young, young, PF_ANY) 594 TESTCLEARFLAG(Young, young, PF_ANY) 595 PAGEFLAG(Idle, idle, PF_ANY) 596 #endif 597 598 #ifdef CONFIG_KASAN_HW_TAGS 599 PAGEFLAG(SkipKASanPoison, skip_kasan_poison, PF_HEAD) 600 #else 601 PAGEFLAG_FALSE(SkipKASanPoison, skip_kasan_poison) 602 #endif 603 604 /* 605 * PageReported() is used to track reported free pages within the Buddy 606 * allocator. We can use the non-atomic version of the test and set 607 * operations as both should be shielded with the zone lock to prevent 608 * any possible races on the setting or clearing of the bit. 609 */ 610 __PAGEFLAG(Reported, reported, PF_NO_COMPOUND) 611 612 #ifdef CONFIG_MEMORY_HOTPLUG 613 PAGEFLAG(VmemmapSelfHosted, vmemmap_self_hosted, PF_ANY) 614 #else 615 PAGEFLAG_FALSE(VmemmapSelfHosted, vmemmap_self_hosted) 616 #endif 617 618 /* 619 * On an anonymous page mapped into a user virtual memory area, 620 * page->mapping points to its anon_vma, not to a struct address_space; 621 * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h. 622 * 623 * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled, 624 * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON 625 * bit; and then page->mapping points, not to an anon_vma, but to a private 626 * structure which KSM associates with that merged page. See ksm.h. 627 * 628 * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable 629 * page and then page->mapping points to a struct movable_operations. 630 * 631 * Please note that, confusingly, "page_mapping" refers to the inode 632 * address_space which maps the page from disk; whereas "page_mapped" 633 * refers to user virtual address space into which the page is mapped. 634 */ 635 #define PAGE_MAPPING_ANON 0x1 636 #define PAGE_MAPPING_MOVABLE 0x2 637 #define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE) 638 #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE) 639 640 /* 641 * Different with flags above, this flag is used only for fsdax mode. It 642 * indicates that this page->mapping is now under reflink case. 643 */ 644 #define PAGE_MAPPING_DAX_COW 0x1 645 646 static __always_inline bool folio_mapping_flags(struct folio *folio) 647 { 648 return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) != 0; 649 } 650 651 static __always_inline int PageMappingFlags(struct page *page) 652 { 653 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0; 654 } 655 656 static __always_inline bool folio_test_anon(struct folio *folio) 657 { 658 return ((unsigned long)folio->mapping & PAGE_MAPPING_ANON) != 0; 659 } 660 661 static __always_inline bool PageAnon(struct page *page) 662 { 663 return folio_test_anon(page_folio(page)); 664 } 665 666 static __always_inline bool __folio_test_movable(const struct folio *folio) 667 { 668 return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) == 669 PAGE_MAPPING_MOVABLE; 670 } 671 672 static __always_inline int __PageMovable(struct page *page) 673 { 674 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == 675 PAGE_MAPPING_MOVABLE; 676 } 677 678 #ifdef CONFIG_KSM 679 /* 680 * A KSM page is one of those write-protected "shared pages" or "merged pages" 681 * which KSM maps into multiple mms, wherever identical anonymous page content 682 * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any 683 * anon_vma, but to that page's node of the stable tree. 684 */ 685 static __always_inline bool folio_test_ksm(struct folio *folio) 686 { 687 return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) == 688 PAGE_MAPPING_KSM; 689 } 690 691 static __always_inline bool PageKsm(struct page *page) 692 { 693 return folio_test_ksm(page_folio(page)); 694 } 695 #else 696 TESTPAGEFLAG_FALSE(Ksm, ksm) 697 #endif 698 699 u64 stable_page_flags(struct page *page); 700 701 /** 702 * folio_test_uptodate - Is this folio up to date? 703 * @folio: The folio. 704 * 705 * The uptodate flag is set on a folio when every byte in the folio is 706 * at least as new as the corresponding bytes on storage. Anonymous 707 * and CoW folios are always uptodate. If the folio is not uptodate, 708 * some of the bytes in it may be; see the is_partially_uptodate() 709 * address_space operation. 710 */ 711 static inline bool folio_test_uptodate(struct folio *folio) 712 { 713 bool ret = test_bit(PG_uptodate, folio_flags(folio, 0)); 714 /* 715 * Must ensure that the data we read out of the folio is loaded 716 * _after_ we've loaded folio->flags to check the uptodate bit. 717 * We can skip the barrier if the folio is not uptodate, because 718 * we wouldn't be reading anything from it. 719 * 720 * See folio_mark_uptodate() for the other side of the story. 721 */ 722 if (ret) 723 smp_rmb(); 724 725 return ret; 726 } 727 728 static inline int PageUptodate(struct page *page) 729 { 730 return folio_test_uptodate(page_folio(page)); 731 } 732 733 static __always_inline void __folio_mark_uptodate(struct folio *folio) 734 { 735 smp_wmb(); 736 __set_bit(PG_uptodate, folio_flags(folio, 0)); 737 } 738 739 static __always_inline void folio_mark_uptodate(struct folio *folio) 740 { 741 /* 742 * Memory barrier must be issued before setting the PG_uptodate bit, 743 * so that all previous stores issued in order to bring the folio 744 * uptodate are actually visible before folio_test_uptodate becomes true. 745 */ 746 smp_wmb(); 747 set_bit(PG_uptodate, folio_flags(folio, 0)); 748 } 749 750 static __always_inline void __SetPageUptodate(struct page *page) 751 { 752 __folio_mark_uptodate((struct folio *)page); 753 } 754 755 static __always_inline void SetPageUptodate(struct page *page) 756 { 757 folio_mark_uptodate((struct folio *)page); 758 } 759 760 CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL) 761 762 bool __folio_start_writeback(struct folio *folio, bool keep_write); 763 bool set_page_writeback(struct page *page); 764 765 #define folio_start_writeback(folio) \ 766 __folio_start_writeback(folio, false) 767 #define folio_start_writeback_keepwrite(folio) \ 768 __folio_start_writeback(folio, true) 769 770 static inline void set_page_writeback_keepwrite(struct page *page) 771 { 772 folio_start_writeback_keepwrite(page_folio(page)); 773 } 774 775 static inline bool test_set_page_writeback(struct page *page) 776 { 777 return set_page_writeback(page); 778 } 779 780 static __always_inline bool folio_test_head(struct folio *folio) 781 { 782 return test_bit(PG_head, folio_flags(folio, FOLIO_PF_ANY)); 783 } 784 785 static __always_inline int PageHead(struct page *page) 786 { 787 PF_POISONED_CHECK(page); 788 return test_bit(PG_head, &page->flags) && !page_is_fake_head(page); 789 } 790 791 __SETPAGEFLAG(Head, head, PF_ANY) 792 __CLEARPAGEFLAG(Head, head, PF_ANY) 793 CLEARPAGEFLAG(Head, head, PF_ANY) 794 795 /** 796 * folio_test_large() - Does this folio contain more than one page? 797 * @folio: The folio to test. 798 * 799 * Return: True if the folio is larger than one page. 800 */ 801 static inline bool folio_test_large(struct folio *folio) 802 { 803 return folio_test_head(folio); 804 } 805 806 static __always_inline void set_compound_head(struct page *page, struct page *head) 807 { 808 WRITE_ONCE(page->compound_head, (unsigned long)head + 1); 809 } 810 811 static __always_inline void clear_compound_head(struct page *page) 812 { 813 WRITE_ONCE(page->compound_head, 0); 814 } 815 816 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 817 static inline void ClearPageCompound(struct page *page) 818 { 819 BUG_ON(!PageHead(page)); 820 ClearPageHead(page); 821 } 822 #endif 823 824 #define PG_head_mask ((1UL << PG_head)) 825 826 #ifdef CONFIG_HUGETLB_PAGE 827 int PageHuge(struct page *page); 828 int PageHeadHuge(struct page *page); 829 static inline bool folio_test_hugetlb(struct folio *folio) 830 { 831 return PageHeadHuge(&folio->page); 832 } 833 #else 834 TESTPAGEFLAG_FALSE(Huge, hugetlb) 835 TESTPAGEFLAG_FALSE(HeadHuge, headhuge) 836 #endif 837 838 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 839 /* 840 * PageHuge() only returns true for hugetlbfs pages, but not for 841 * normal or transparent huge pages. 842 * 843 * PageTransHuge() returns true for both transparent huge and 844 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be 845 * called only in the core VM paths where hugetlbfs pages can't exist. 846 */ 847 static inline int PageTransHuge(struct page *page) 848 { 849 VM_BUG_ON_PAGE(PageTail(page), page); 850 return PageHead(page); 851 } 852 853 static inline bool folio_test_transhuge(struct folio *folio) 854 { 855 return folio_test_head(folio); 856 } 857 858 /* 859 * PageTransCompound returns true for both transparent huge pages 860 * and hugetlbfs pages, so it should only be called when it's known 861 * that hugetlbfs pages aren't involved. 862 */ 863 static inline int PageTransCompound(struct page *page) 864 { 865 return PageCompound(page); 866 } 867 868 /* 869 * PageTransTail returns true for both transparent huge pages 870 * and hugetlbfs pages, so it should only be called when it's known 871 * that hugetlbfs pages aren't involved. 872 */ 873 static inline int PageTransTail(struct page *page) 874 { 875 return PageTail(page); 876 } 877 878 /* 879 * PageDoubleMap indicates that the compound page is mapped with PTEs as well 880 * as PMDs. 881 * 882 * This is required for optimization of rmap operations for THP: we can postpone 883 * per small page mapcount accounting (and its overhead from atomic operations) 884 * until the first PMD split. 885 * 886 * For the page PageDoubleMap means ->_mapcount in all sub-pages is offset up 887 * by one. This reference will go away with last compound_mapcount. 888 * 889 * See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap(). 890 */ 891 PAGEFLAG(DoubleMap, double_map, PF_SECOND) 892 TESTSCFLAG(DoubleMap, double_map, PF_SECOND) 893 #else 894 TESTPAGEFLAG_FALSE(TransHuge, transhuge) 895 TESTPAGEFLAG_FALSE(TransCompound, transcompound) 896 TESTPAGEFLAG_FALSE(TransCompoundMap, transcompoundmap) 897 TESTPAGEFLAG_FALSE(TransTail, transtail) 898 PAGEFLAG_FALSE(DoubleMap, double_map) 899 TESTSCFLAG_FALSE(DoubleMap, double_map) 900 #endif 901 902 #if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_TRANSPARENT_HUGEPAGE) 903 /* 904 * PageHasHWPoisoned indicates that at least one subpage is hwpoisoned in the 905 * compound page. 906 * 907 * This flag is set by hwpoison handler. Cleared by THP split or free page. 908 */ 909 PAGEFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND) 910 TESTSCFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND) 911 #else 912 PAGEFLAG_FALSE(HasHWPoisoned, has_hwpoisoned) 913 TESTSCFLAG_FALSE(HasHWPoisoned, has_hwpoisoned) 914 #endif 915 916 /* 917 * Check if a page is currently marked HWPoisoned. Note that this check is 918 * best effort only and inherently racy: there is no way to synchronize with 919 * failing hardware. 920 */ 921 static inline bool is_page_hwpoison(struct page *page) 922 { 923 if (PageHWPoison(page)) 924 return true; 925 return PageHuge(page) && PageHWPoison(compound_head(page)); 926 } 927 928 /* 929 * For pages that are never mapped to userspace (and aren't PageSlab), 930 * page_type may be used. Because it is initialised to -1, we invert the 931 * sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and 932 * __ClearPageFoo *sets* the bit used for PageFoo. We reserve a few high and 933 * low bits so that an underflow or overflow of page_mapcount() won't be 934 * mistaken for a page type value. 935 */ 936 937 #define PAGE_TYPE_BASE 0xf0000000 938 /* Reserve 0x0000007f to catch underflows of page_mapcount */ 939 #define PAGE_MAPCOUNT_RESERVE -128 940 #define PG_buddy 0x00000080 941 #define PG_offline 0x00000100 942 #define PG_table 0x00000200 943 #define PG_guard 0x00000400 944 945 #define PageType(page, flag) \ 946 ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE) 947 948 static inline int page_has_type(struct page *page) 949 { 950 return (int)page->page_type < PAGE_MAPCOUNT_RESERVE; 951 } 952 953 #define PAGE_TYPE_OPS(uname, lname) \ 954 static __always_inline int Page##uname(struct page *page) \ 955 { \ 956 return PageType(page, PG_##lname); \ 957 } \ 958 static __always_inline void __SetPage##uname(struct page *page) \ 959 { \ 960 VM_BUG_ON_PAGE(!PageType(page, 0), page); \ 961 page->page_type &= ~PG_##lname; \ 962 } \ 963 static __always_inline void __ClearPage##uname(struct page *page) \ 964 { \ 965 VM_BUG_ON_PAGE(!Page##uname(page), page); \ 966 page->page_type |= PG_##lname; \ 967 } 968 969 /* 970 * PageBuddy() indicates that the page is free and in the buddy system 971 * (see mm/page_alloc.c). 972 */ 973 PAGE_TYPE_OPS(Buddy, buddy) 974 975 /* 976 * PageOffline() indicates that the page is logically offline although the 977 * containing section is online. (e.g. inflated in a balloon driver or 978 * not onlined when onlining the section). 979 * The content of these pages is effectively stale. Such pages should not 980 * be touched (read/write/dump/save) except by their owner. 981 * 982 * If a driver wants to allow to offline unmovable PageOffline() pages without 983 * putting them back to the buddy, it can do so via the memory notifier by 984 * decrementing the reference count in MEM_GOING_OFFLINE and incrementing the 985 * reference count in MEM_CANCEL_OFFLINE. When offlining, the PageOffline() 986 * pages (now with a reference count of zero) are treated like free pages, 987 * allowing the containing memory block to get offlined. A driver that 988 * relies on this feature is aware that re-onlining the memory block will 989 * require to re-set the pages PageOffline() and not giving them to the 990 * buddy via online_page_callback_t. 991 * 992 * There are drivers that mark a page PageOffline() and expect there won't be 993 * any further access to page content. PFN walkers that read content of random 994 * pages should check PageOffline() and synchronize with such drivers using 995 * page_offline_freeze()/page_offline_thaw(). 996 */ 997 PAGE_TYPE_OPS(Offline, offline) 998 999 extern void page_offline_freeze(void); 1000 extern void page_offline_thaw(void); 1001 extern void page_offline_begin(void); 1002 extern void page_offline_end(void); 1003 1004 /* 1005 * Marks pages in use as page tables. 1006 */ 1007 PAGE_TYPE_OPS(Table, table) 1008 1009 /* 1010 * Marks guardpages used with debug_pagealloc. 1011 */ 1012 PAGE_TYPE_OPS(Guard, guard) 1013 1014 extern bool is_free_buddy_page(struct page *page); 1015 1016 PAGEFLAG(Isolated, isolated, PF_ANY); 1017 1018 static __always_inline int PageAnonExclusive(struct page *page) 1019 { 1020 VM_BUG_ON_PGFLAGS(!PageAnon(page), page); 1021 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); 1022 return test_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags); 1023 } 1024 1025 static __always_inline void SetPageAnonExclusive(struct page *page) 1026 { 1027 VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page); 1028 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); 1029 set_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags); 1030 } 1031 1032 static __always_inline void ClearPageAnonExclusive(struct page *page) 1033 { 1034 VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page); 1035 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); 1036 clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags); 1037 } 1038 1039 static __always_inline void __ClearPageAnonExclusive(struct page *page) 1040 { 1041 VM_BUG_ON_PGFLAGS(!PageAnon(page), page); 1042 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); 1043 __clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags); 1044 } 1045 1046 #ifdef CONFIG_MMU 1047 #define __PG_MLOCKED (1UL << PG_mlocked) 1048 #else 1049 #define __PG_MLOCKED 0 1050 #endif 1051 1052 /* 1053 * Flags checked when a page is freed. Pages being freed should not have 1054 * these flags set. If they are, there is a problem. 1055 */ 1056 #define PAGE_FLAGS_CHECK_AT_FREE \ 1057 (1UL << PG_lru | 1UL << PG_locked | \ 1058 1UL << PG_private | 1UL << PG_private_2 | \ 1059 1UL << PG_writeback | 1UL << PG_reserved | \ 1060 1UL << PG_slab | 1UL << PG_active | \ 1061 1UL << PG_unevictable | __PG_MLOCKED | LRU_GEN_MASK) 1062 1063 /* 1064 * Flags checked when a page is prepped for return by the page allocator. 1065 * Pages being prepped should not have these flags set. If they are set, 1066 * there has been a kernel bug or struct page corruption. 1067 * 1068 * __PG_HWPOISON is exceptional because it needs to be kept beyond page's 1069 * alloc-free cycle to prevent from reusing the page. 1070 */ 1071 #define PAGE_FLAGS_CHECK_AT_PREP \ 1072 ((PAGEFLAGS_MASK & ~__PG_HWPOISON) | LRU_GEN_MASK | LRU_REFS_MASK) 1073 1074 #define PAGE_FLAGS_PRIVATE \ 1075 (1UL << PG_private | 1UL << PG_private_2) 1076 /** 1077 * page_has_private - Determine if page has private stuff 1078 * @page: The page to be checked 1079 * 1080 * Determine if a page has private stuff, indicating that release routines 1081 * should be invoked upon it. 1082 */ 1083 static inline int page_has_private(struct page *page) 1084 { 1085 return !!(page->flags & PAGE_FLAGS_PRIVATE); 1086 } 1087 1088 static inline bool folio_has_private(struct folio *folio) 1089 { 1090 return page_has_private(&folio->page); 1091 } 1092 1093 #undef PF_ANY 1094 #undef PF_HEAD 1095 #undef PF_ONLY_HEAD 1096 #undef PF_NO_TAIL 1097 #undef PF_NO_COMPOUND 1098 #undef PF_SECOND 1099 #endif /* !__GENERATING_BOUNDS_H */ 1100 1101 #endif /* PAGE_FLAGS_H */ 1102