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_writeback, /* Page is under writeback */ 103 PG_referenced, 104 PG_uptodate, 105 PG_dirty, 106 PG_lru, 107 PG_head, /* Must be in bit 6 */ 108 PG_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */ 109 PG_active, 110 PG_workingset, 111 PG_error, 112 PG_slab, 113 PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/ 114 PG_arch_1, 115 PG_reserved, 116 PG_private, /* If pagecache, has fs-private data */ 117 PG_private_2, /* If pagecache, has fs aux data */ 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_ARCH_USES_PG_ARCH_X 136 PG_arch_2, 137 PG_arch_3, 138 #endif 139 __NR_PAGEFLAGS, 140 141 PG_readahead = PG_reclaim, 142 143 /* 144 * Depending on the way an anonymous folio can be mapped into a page 145 * table (e.g., single PMD/PUD/CONT of the head page vs. PTE-mapped 146 * THP), PG_anon_exclusive may be set only for the head page or for 147 * tail pages of an anonymous folio. For now, we only expect it to be 148 * set on tail pages for PTE-mapped THP. 149 */ 150 PG_anon_exclusive = PG_mappedtodisk, 151 152 /* Filesystems */ 153 PG_checked = PG_owner_priv_1, 154 155 /* SwapBacked */ 156 PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */ 157 158 /* Two page bits are conscripted by FS-Cache to maintain local caching 159 * state. These bits are set on pages belonging to the netfs's inodes 160 * when those inodes are being locally cached. 161 */ 162 PG_fscache = PG_private_2, /* page backed by cache */ 163 164 /* XEN */ 165 /* Pinned in Xen as a read-only pagetable page. */ 166 PG_pinned = PG_owner_priv_1, 167 /* Pinned as part of domain save (see xen_mm_pin_all()). */ 168 PG_savepinned = PG_dirty, 169 /* Has a grant mapping of another (foreign) domain's page. */ 170 PG_foreign = PG_owner_priv_1, 171 /* Remapped by swiotlb-xen. */ 172 PG_xen_remapped = PG_owner_priv_1, 173 174 /* non-lru isolated movable page */ 175 PG_isolated = PG_reclaim, 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_error, 193 PG_large_rmappable = PG_workingset, /* anon or file-backed */ 194 }; 195 196 #define PAGEFLAGS_MASK ((1UL << NR_PAGEFLAGS) - 1) 197 198 #ifndef __GENERATING_BOUNDS_H 199 200 #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP 201 DECLARE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key); 202 203 /* 204 * Return the real head page struct iff the @page is a fake head page, otherwise 205 * return the @page itself. See Documentation/mm/vmemmap_dedup.rst. 206 */ 207 static __always_inline const struct page *page_fixed_fake_head(const struct page *page) 208 { 209 if (!static_branch_unlikely(&hugetlb_optimize_vmemmap_key)) 210 return page; 211 212 /* 213 * Only addresses aligned with PAGE_SIZE of struct page may be fake head 214 * struct page. The alignment check aims to avoid access the fields ( 215 * e.g. compound_head) of the @page[1]. It can avoid touch a (possibly) 216 * cold cacheline in some cases. 217 */ 218 if (IS_ALIGNED((unsigned long)page, PAGE_SIZE) && 219 test_bit(PG_head, &page->flags)) { 220 /* 221 * We can safely access the field of the @page[1] with PG_head 222 * because the @page is a compound page composed with at least 223 * two contiguous pages. 224 */ 225 unsigned long head = READ_ONCE(page[1].compound_head); 226 227 if (likely(head & 1)) 228 return (const struct page *)(head - 1); 229 } 230 return page; 231 } 232 #else 233 static inline const struct page *page_fixed_fake_head(const struct page *page) 234 { 235 return page; 236 } 237 #endif 238 239 static __always_inline int page_is_fake_head(const struct page *page) 240 { 241 return page_fixed_fake_head(page) != page; 242 } 243 244 static inline unsigned long _compound_head(const struct page *page) 245 { 246 unsigned long head = READ_ONCE(page->compound_head); 247 248 if (unlikely(head & 1)) 249 return head - 1; 250 return (unsigned long)page_fixed_fake_head(page); 251 } 252 253 #define compound_head(page) ((typeof(page))_compound_head(page)) 254 255 /** 256 * page_folio - Converts from page to folio. 257 * @p: The page. 258 * 259 * Every page is part of a folio. This function cannot be called on a 260 * NULL pointer. 261 * 262 * Context: No reference, nor lock is required on @page. If the caller 263 * does not hold a reference, this call may race with a folio split, so 264 * it should re-check the folio still contains this page after gaining 265 * a reference on the folio. 266 * Return: The folio which contains this page. 267 */ 268 #define page_folio(p) (_Generic((p), \ 269 const struct page *: (const struct folio *)_compound_head(p), \ 270 struct page *: (struct folio *)_compound_head(p))) 271 272 /** 273 * folio_page - Return a page from a folio. 274 * @folio: The folio. 275 * @n: The page number to return. 276 * 277 * @n is relative to the start of the folio. This function does not 278 * check that the page number lies within @folio; the caller is presumed 279 * to have a reference to the page. 280 */ 281 #define folio_page(folio, n) nth_page(&(folio)->page, n) 282 283 static __always_inline int PageTail(const struct page *page) 284 { 285 return READ_ONCE(page->compound_head) & 1 || page_is_fake_head(page); 286 } 287 288 static __always_inline int PageCompound(const struct page *page) 289 { 290 return test_bit(PG_head, &page->flags) || 291 READ_ONCE(page->compound_head) & 1; 292 } 293 294 #define PAGE_POISON_PATTERN -1l 295 static inline int PagePoisoned(const struct page *page) 296 { 297 return READ_ONCE(page->flags) == PAGE_POISON_PATTERN; 298 } 299 300 #ifdef CONFIG_DEBUG_VM 301 void page_init_poison(struct page *page, size_t size); 302 #else 303 static inline void page_init_poison(struct page *page, size_t size) 304 { 305 } 306 #endif 307 308 static const unsigned long *const_folio_flags(const struct folio *folio, 309 unsigned n) 310 { 311 const struct page *page = &folio->page; 312 313 VM_BUG_ON_PGFLAGS(PageTail(page), page); 314 VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page); 315 return &page[n].flags; 316 } 317 318 static unsigned long *folio_flags(struct folio *folio, unsigned n) 319 { 320 struct page *page = &folio->page; 321 322 VM_BUG_ON_PGFLAGS(PageTail(page), page); 323 VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page); 324 return &page[n].flags; 325 } 326 327 /* 328 * Page flags policies wrt compound pages 329 * 330 * PF_POISONED_CHECK 331 * check if this struct page poisoned/uninitialized 332 * 333 * PF_ANY: 334 * the page flag is relevant for small, head and tail pages. 335 * 336 * PF_HEAD: 337 * for compound page all operations related to the page flag applied to 338 * 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_NO_TAIL(page, enforce) ({ \ 356 VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \ 357 PF_POISONED_CHECK(compound_head(page)); }) 358 #define PF_NO_COMPOUND(page, enforce) ({ \ 359 VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \ 360 PF_POISONED_CHECK(page); }) 361 #define PF_SECOND(page, enforce) ({ \ 362 VM_BUG_ON_PGFLAGS(!PageHead(page), page); \ 363 PF_POISONED_CHECK(&page[1]); }) 364 365 /* Which page is the flag stored in */ 366 #define FOLIO_PF_ANY 0 367 #define FOLIO_PF_HEAD 0 368 #define FOLIO_PF_NO_TAIL 0 369 #define FOLIO_PF_NO_COMPOUND 0 370 #define FOLIO_PF_SECOND 1 371 372 #define FOLIO_HEAD_PAGE 0 373 #define FOLIO_SECOND_PAGE 1 374 375 /* 376 * Macros to create function definitions for page flags 377 */ 378 #define FOLIO_TEST_FLAG(name, page) \ 379 static __always_inline bool folio_test_##name(const struct folio *folio) \ 380 { return test_bit(PG_##name, const_folio_flags(folio, page)); } 381 382 #define FOLIO_SET_FLAG(name, page) \ 383 static __always_inline void folio_set_##name(struct folio *folio) \ 384 { set_bit(PG_##name, folio_flags(folio, page)); } 385 386 #define FOLIO_CLEAR_FLAG(name, page) \ 387 static __always_inline void folio_clear_##name(struct folio *folio) \ 388 { clear_bit(PG_##name, folio_flags(folio, page)); } 389 390 #define __FOLIO_SET_FLAG(name, page) \ 391 static __always_inline void __folio_set_##name(struct folio *folio) \ 392 { __set_bit(PG_##name, folio_flags(folio, page)); } 393 394 #define __FOLIO_CLEAR_FLAG(name, page) \ 395 static __always_inline void __folio_clear_##name(struct folio *folio) \ 396 { __clear_bit(PG_##name, folio_flags(folio, page)); } 397 398 #define FOLIO_TEST_SET_FLAG(name, page) \ 399 static __always_inline bool folio_test_set_##name(struct folio *folio) \ 400 { return test_and_set_bit(PG_##name, folio_flags(folio, page)); } 401 402 #define FOLIO_TEST_CLEAR_FLAG(name, page) \ 403 static __always_inline bool folio_test_clear_##name(struct folio *folio) \ 404 { return test_and_clear_bit(PG_##name, folio_flags(folio, page)); } 405 406 #define FOLIO_FLAG(name, page) \ 407 FOLIO_TEST_FLAG(name, page) \ 408 FOLIO_SET_FLAG(name, page) \ 409 FOLIO_CLEAR_FLAG(name, page) 410 411 #define TESTPAGEFLAG(uname, lname, policy) \ 412 FOLIO_TEST_FLAG(lname, FOLIO_##policy) \ 413 static __always_inline int Page##uname(const struct page *page) \ 414 { return test_bit(PG_##lname, &policy(page, 0)->flags); } 415 416 #define SETPAGEFLAG(uname, lname, policy) \ 417 FOLIO_SET_FLAG(lname, FOLIO_##policy) \ 418 static __always_inline void SetPage##uname(struct page *page) \ 419 { set_bit(PG_##lname, &policy(page, 1)->flags); } 420 421 #define CLEARPAGEFLAG(uname, lname, policy) \ 422 FOLIO_CLEAR_FLAG(lname, FOLIO_##policy) \ 423 static __always_inline void ClearPage##uname(struct page *page) \ 424 { clear_bit(PG_##lname, &policy(page, 1)->flags); } 425 426 #define __SETPAGEFLAG(uname, lname, policy) \ 427 __FOLIO_SET_FLAG(lname, FOLIO_##policy) \ 428 static __always_inline void __SetPage##uname(struct page *page) \ 429 { __set_bit(PG_##lname, &policy(page, 1)->flags); } 430 431 #define __CLEARPAGEFLAG(uname, lname, policy) \ 432 __FOLIO_CLEAR_FLAG(lname, FOLIO_##policy) \ 433 static __always_inline void __ClearPage##uname(struct page *page) \ 434 { __clear_bit(PG_##lname, &policy(page, 1)->flags); } 435 436 #define TESTSETFLAG(uname, lname, policy) \ 437 FOLIO_TEST_SET_FLAG(lname, FOLIO_##policy) \ 438 static __always_inline int TestSetPage##uname(struct page *page) \ 439 { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); } 440 441 #define TESTCLEARFLAG(uname, lname, policy) \ 442 FOLIO_TEST_CLEAR_FLAG(lname, FOLIO_##policy) \ 443 static __always_inline int TestClearPage##uname(struct page *page) \ 444 { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); } 445 446 #define PAGEFLAG(uname, lname, policy) \ 447 TESTPAGEFLAG(uname, lname, policy) \ 448 SETPAGEFLAG(uname, lname, policy) \ 449 CLEARPAGEFLAG(uname, lname, policy) 450 451 #define __PAGEFLAG(uname, lname, policy) \ 452 TESTPAGEFLAG(uname, lname, policy) \ 453 __SETPAGEFLAG(uname, lname, policy) \ 454 __CLEARPAGEFLAG(uname, lname, policy) 455 456 #define TESTSCFLAG(uname, lname, policy) \ 457 TESTSETFLAG(uname, lname, policy) \ 458 TESTCLEARFLAG(uname, lname, policy) 459 460 #define FOLIO_TEST_FLAG_FALSE(name) \ 461 static inline bool folio_test_##name(const struct folio *folio) \ 462 { return false; } 463 #define FOLIO_SET_FLAG_NOOP(name) \ 464 static inline void folio_set_##name(struct folio *folio) { } 465 #define FOLIO_CLEAR_FLAG_NOOP(name) \ 466 static inline void folio_clear_##name(struct folio *folio) { } 467 #define __FOLIO_SET_FLAG_NOOP(name) \ 468 static inline void __folio_set_##name(struct folio *folio) { } 469 #define __FOLIO_CLEAR_FLAG_NOOP(name) \ 470 static inline void __folio_clear_##name(struct folio *folio) { } 471 #define FOLIO_TEST_SET_FLAG_FALSE(name) \ 472 static inline bool folio_test_set_##name(struct folio *folio) \ 473 { return false; } 474 #define FOLIO_TEST_CLEAR_FLAG_FALSE(name) \ 475 static inline bool folio_test_clear_##name(struct folio *folio) \ 476 { return false; } 477 478 #define FOLIO_FLAG_FALSE(name) \ 479 FOLIO_TEST_FLAG_FALSE(name) \ 480 FOLIO_SET_FLAG_NOOP(name) \ 481 FOLIO_CLEAR_FLAG_NOOP(name) 482 483 #define TESTPAGEFLAG_FALSE(uname, lname) \ 484 FOLIO_TEST_FLAG_FALSE(lname) \ 485 static inline int Page##uname(const struct page *page) { return 0; } 486 487 #define SETPAGEFLAG_NOOP(uname, lname) \ 488 FOLIO_SET_FLAG_NOOP(lname) \ 489 static inline void SetPage##uname(struct page *page) { } 490 491 #define CLEARPAGEFLAG_NOOP(uname, lname) \ 492 FOLIO_CLEAR_FLAG_NOOP(lname) \ 493 static inline void ClearPage##uname(struct page *page) { } 494 495 #define __CLEARPAGEFLAG_NOOP(uname, lname) \ 496 __FOLIO_CLEAR_FLAG_NOOP(lname) \ 497 static inline void __ClearPage##uname(struct page *page) { } 498 499 #define TESTSETFLAG_FALSE(uname, lname) \ 500 FOLIO_TEST_SET_FLAG_FALSE(lname) \ 501 static inline int TestSetPage##uname(struct page *page) { return 0; } 502 503 #define TESTCLEARFLAG_FALSE(uname, lname) \ 504 FOLIO_TEST_CLEAR_FLAG_FALSE(lname) \ 505 static inline int TestClearPage##uname(struct page *page) { return 0; } 506 507 #define PAGEFLAG_FALSE(uname, lname) TESTPAGEFLAG_FALSE(uname, lname) \ 508 SETPAGEFLAG_NOOP(uname, lname) CLEARPAGEFLAG_NOOP(uname, lname) 509 510 #define TESTSCFLAG_FALSE(uname, lname) \ 511 TESTSETFLAG_FALSE(uname, lname) TESTCLEARFLAG_FALSE(uname, lname) 512 513 __PAGEFLAG(Locked, locked, PF_NO_TAIL) 514 FOLIO_FLAG(waiters, FOLIO_HEAD_PAGE) 515 PAGEFLAG(Error, error, PF_NO_TAIL) TESTCLEARFLAG(Error, error, PF_NO_TAIL) 516 PAGEFLAG(Referenced, referenced, PF_HEAD) 517 TESTCLEARFLAG(Referenced, referenced, PF_HEAD) 518 __SETPAGEFLAG(Referenced, referenced, PF_HEAD) 519 PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD) 520 __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD) 521 PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD) 522 TESTCLEARFLAG(LRU, lru, PF_HEAD) 523 PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD) 524 TESTCLEARFLAG(Active, active, PF_HEAD) 525 PAGEFLAG(Workingset, workingset, PF_HEAD) 526 TESTCLEARFLAG(Workingset, workingset, PF_HEAD) 527 __PAGEFLAG(Slab, slab, PF_NO_TAIL) 528 PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */ 529 530 /* Xen */ 531 PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND) 532 TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND) 533 PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND); 534 PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND); 535 PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND) 536 TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND) 537 538 PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) 539 __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) 540 __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) 541 PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) 542 __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) 543 __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) 544 545 /* 546 * Private page markings that may be used by the filesystem that owns the page 547 * for its own purposes. 548 * - PG_private and PG_private_2 cause release_folio() and co to be invoked 549 */ 550 PAGEFLAG(Private, private, PF_ANY) 551 PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY) 552 PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY) 553 TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY) 554 555 /* 556 * Only test-and-set exist for PG_writeback. The unconditional operators are 557 * risky: they bypass page accounting. 558 */ 559 TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL) 560 TESTSCFLAG(Writeback, writeback, PF_NO_TAIL) 561 PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL) 562 563 /* PG_readahead is only used for reads; PG_reclaim is only for writes */ 564 PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL) 565 TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL) 566 PAGEFLAG(Readahead, readahead, PF_NO_COMPOUND) 567 TESTCLEARFLAG(Readahead, readahead, PF_NO_COMPOUND) 568 569 #ifdef CONFIG_HIGHMEM 570 /* 571 * Must use a macro here due to header dependency issues. page_zone() is not 572 * available at this point. 573 */ 574 #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p)) 575 #define folio_test_highmem(__f) is_highmem_idx(folio_zonenum(__f)) 576 #else 577 PAGEFLAG_FALSE(HighMem, highmem) 578 #endif 579 580 #ifdef CONFIG_SWAP 581 static __always_inline bool folio_test_swapcache(const struct folio *folio) 582 { 583 return folio_test_swapbacked(folio) && 584 test_bit(PG_swapcache, const_folio_flags(folio, 0)); 585 } 586 587 static __always_inline bool PageSwapCache(const struct page *page) 588 { 589 return folio_test_swapcache(page_folio(page)); 590 } 591 592 SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL) 593 CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL) 594 #else 595 PAGEFLAG_FALSE(SwapCache, swapcache) 596 #endif 597 598 PAGEFLAG(Unevictable, unevictable, PF_HEAD) 599 __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD) 600 TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD) 601 602 #ifdef CONFIG_MMU 603 PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL) 604 __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL) 605 TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL) 606 #else 607 PAGEFLAG_FALSE(Mlocked, mlocked) __CLEARPAGEFLAG_NOOP(Mlocked, mlocked) 608 TESTSCFLAG_FALSE(Mlocked, mlocked) 609 #endif 610 611 #ifdef CONFIG_ARCH_USES_PG_UNCACHED 612 PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND) 613 #else 614 PAGEFLAG_FALSE(Uncached, uncached) 615 #endif 616 617 #ifdef CONFIG_MEMORY_FAILURE 618 PAGEFLAG(HWPoison, hwpoison, PF_ANY) 619 TESTSCFLAG(HWPoison, hwpoison, PF_ANY) 620 #define __PG_HWPOISON (1UL << PG_hwpoison) 621 #define MAGIC_HWPOISON 0x48575053U /* HWPS */ 622 extern void SetPageHWPoisonTakenOff(struct page *page); 623 extern void ClearPageHWPoisonTakenOff(struct page *page); 624 extern bool take_page_off_buddy(struct page *page); 625 extern bool put_page_back_buddy(struct page *page); 626 #else 627 PAGEFLAG_FALSE(HWPoison, hwpoison) 628 #define __PG_HWPOISON 0 629 #endif 630 631 #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT) 632 FOLIO_TEST_FLAG(young, FOLIO_HEAD_PAGE) 633 FOLIO_SET_FLAG(young, FOLIO_HEAD_PAGE) 634 FOLIO_TEST_CLEAR_FLAG(young, FOLIO_HEAD_PAGE) 635 FOLIO_FLAG(idle, FOLIO_HEAD_PAGE) 636 #endif 637 638 /* 639 * PageReported() is used to track reported free pages within the Buddy 640 * allocator. We can use the non-atomic version of the test and set 641 * operations as both should be shielded with the zone lock to prevent 642 * any possible races on the setting or clearing of the bit. 643 */ 644 __PAGEFLAG(Reported, reported, PF_NO_COMPOUND) 645 646 #ifdef CONFIG_MEMORY_HOTPLUG 647 PAGEFLAG(VmemmapSelfHosted, vmemmap_self_hosted, PF_ANY) 648 #else 649 PAGEFLAG_FALSE(VmemmapSelfHosted, vmemmap_self_hosted) 650 #endif 651 652 /* 653 * On an anonymous page mapped into a user virtual memory area, 654 * page->mapping points to its anon_vma, not to a struct address_space; 655 * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h. 656 * 657 * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled, 658 * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON 659 * bit; and then page->mapping points, not to an anon_vma, but to a private 660 * structure which KSM associates with that merged page. See ksm.h. 661 * 662 * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable 663 * page and then page->mapping points to a struct movable_operations. 664 * 665 * Please note that, confusingly, "page_mapping" refers to the inode 666 * address_space which maps the page from disk; whereas "page_mapped" 667 * refers to user virtual address space into which the page is mapped. 668 * 669 * For slab pages, since slab reuses the bits in struct page to store its 670 * internal states, the page->mapping does not exist as such, nor do these 671 * flags below. So in order to avoid testing non-existent bits, please 672 * make sure that PageSlab(page) actually evaluates to false before calling 673 * the following functions (e.g., PageAnon). See mm/slab.h. 674 */ 675 #define PAGE_MAPPING_ANON 0x1 676 #define PAGE_MAPPING_MOVABLE 0x2 677 #define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE) 678 #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE) 679 680 /* 681 * Different with flags above, this flag is used only for fsdax mode. It 682 * indicates that this page->mapping is now under reflink case. 683 */ 684 #define PAGE_MAPPING_DAX_SHARED ((void *)0x1) 685 686 static __always_inline bool folio_mapping_flags(const struct folio *folio) 687 { 688 return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) != 0; 689 } 690 691 static __always_inline int PageMappingFlags(const struct page *page) 692 { 693 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0; 694 } 695 696 static __always_inline bool folio_test_anon(const struct folio *folio) 697 { 698 return ((unsigned long)folio->mapping & PAGE_MAPPING_ANON) != 0; 699 } 700 701 static __always_inline bool PageAnon(const struct page *page) 702 { 703 return folio_test_anon(page_folio(page)); 704 } 705 706 static __always_inline bool __folio_test_movable(const struct folio *folio) 707 { 708 return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) == 709 PAGE_MAPPING_MOVABLE; 710 } 711 712 static __always_inline int __PageMovable(const struct page *page) 713 { 714 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == 715 PAGE_MAPPING_MOVABLE; 716 } 717 718 #ifdef CONFIG_KSM 719 /* 720 * A KSM page is one of those write-protected "shared pages" or "merged pages" 721 * which KSM maps into multiple mms, wherever identical anonymous page content 722 * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any 723 * anon_vma, but to that page's node of the stable tree. 724 */ 725 static __always_inline bool folio_test_ksm(const struct folio *folio) 726 { 727 return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) == 728 PAGE_MAPPING_KSM; 729 } 730 731 static __always_inline bool PageKsm(const struct page *page) 732 { 733 return folio_test_ksm(page_folio(page)); 734 } 735 #else 736 TESTPAGEFLAG_FALSE(Ksm, ksm) 737 #endif 738 739 u64 stable_page_flags(struct page *page); 740 741 /** 742 * folio_xor_flags_has_waiters - Change some folio flags. 743 * @folio: The folio. 744 * @mask: Bits set in this word will be changed. 745 * 746 * This must only be used for flags which are changed with the folio 747 * lock held. For example, it is unsafe to use for PG_dirty as that 748 * can be set without the folio lock held. It can also only be used 749 * on flags which are in the range 0-6 as some of the implementations 750 * only affect those bits. 751 * 752 * Return: Whether there are tasks waiting on the folio. 753 */ 754 static inline bool folio_xor_flags_has_waiters(struct folio *folio, 755 unsigned long mask) 756 { 757 return xor_unlock_is_negative_byte(mask, folio_flags(folio, 0)); 758 } 759 760 /** 761 * folio_test_uptodate - Is this folio up to date? 762 * @folio: The folio. 763 * 764 * The uptodate flag is set on a folio when every byte in the folio is 765 * at least as new as the corresponding bytes on storage. Anonymous 766 * and CoW folios are always uptodate. If the folio is not uptodate, 767 * some of the bytes in it may be; see the is_partially_uptodate() 768 * address_space operation. 769 */ 770 static inline bool folio_test_uptodate(const struct folio *folio) 771 { 772 bool ret = test_bit(PG_uptodate, const_folio_flags(folio, 0)); 773 /* 774 * Must ensure that the data we read out of the folio is loaded 775 * _after_ we've loaded folio->flags to check the uptodate bit. 776 * We can skip the barrier if the folio is not uptodate, because 777 * we wouldn't be reading anything from it. 778 * 779 * See folio_mark_uptodate() for the other side of the story. 780 */ 781 if (ret) 782 smp_rmb(); 783 784 return ret; 785 } 786 787 static inline int PageUptodate(const struct page *page) 788 { 789 return folio_test_uptodate(page_folio(page)); 790 } 791 792 static __always_inline void __folio_mark_uptodate(struct folio *folio) 793 { 794 smp_wmb(); 795 __set_bit(PG_uptodate, folio_flags(folio, 0)); 796 } 797 798 static __always_inline void folio_mark_uptodate(struct folio *folio) 799 { 800 /* 801 * Memory barrier must be issued before setting the PG_uptodate bit, 802 * so that all previous stores issued in order to bring the folio 803 * uptodate are actually visible before folio_test_uptodate becomes true. 804 */ 805 smp_wmb(); 806 set_bit(PG_uptodate, folio_flags(folio, 0)); 807 } 808 809 static __always_inline void __SetPageUptodate(struct page *page) 810 { 811 __folio_mark_uptodate((struct folio *)page); 812 } 813 814 static __always_inline void SetPageUptodate(struct page *page) 815 { 816 folio_mark_uptodate((struct folio *)page); 817 } 818 819 CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL) 820 821 void __folio_start_writeback(struct folio *folio, bool keep_write); 822 void set_page_writeback(struct page *page); 823 824 #define folio_start_writeback(folio) \ 825 __folio_start_writeback(folio, false) 826 #define folio_start_writeback_keepwrite(folio) \ 827 __folio_start_writeback(folio, true) 828 829 static __always_inline bool folio_test_head(const struct folio *folio) 830 { 831 return test_bit(PG_head, const_folio_flags(folio, FOLIO_PF_ANY)); 832 } 833 834 static __always_inline int PageHead(const struct page *page) 835 { 836 PF_POISONED_CHECK(page); 837 return test_bit(PG_head, &page->flags) && !page_is_fake_head(page); 838 } 839 840 __SETPAGEFLAG(Head, head, PF_ANY) 841 __CLEARPAGEFLAG(Head, head, PF_ANY) 842 CLEARPAGEFLAG(Head, head, PF_ANY) 843 844 /** 845 * folio_test_large() - Does this folio contain more than one page? 846 * @folio: The folio to test. 847 * 848 * Return: True if the folio is larger than one page. 849 */ 850 static inline bool folio_test_large(const struct folio *folio) 851 { 852 return folio_test_head(folio); 853 } 854 855 static __always_inline void set_compound_head(struct page *page, struct page *head) 856 { 857 WRITE_ONCE(page->compound_head, (unsigned long)head + 1); 858 } 859 860 static __always_inline void clear_compound_head(struct page *page) 861 { 862 WRITE_ONCE(page->compound_head, 0); 863 } 864 865 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 866 static inline void ClearPageCompound(struct page *page) 867 { 868 BUG_ON(!PageHead(page)); 869 ClearPageHead(page); 870 } 871 PAGEFLAG(LargeRmappable, large_rmappable, PF_SECOND) 872 #else 873 TESTPAGEFLAG_FALSE(LargeRmappable, large_rmappable) 874 #endif 875 876 #define PG_head_mask ((1UL << PG_head)) 877 878 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 879 /* 880 * PageHuge() only returns true for hugetlbfs pages, but not for 881 * normal or transparent huge pages. 882 * 883 * PageTransHuge() returns true for both transparent huge and 884 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be 885 * called only in the core VM paths where hugetlbfs pages can't exist. 886 */ 887 static inline int PageTransHuge(const struct page *page) 888 { 889 VM_BUG_ON_PAGE(PageTail(page), page); 890 return PageHead(page); 891 } 892 893 /* 894 * PageTransCompound returns true for both transparent huge pages 895 * and hugetlbfs pages, so it should only be called when it's known 896 * that hugetlbfs pages aren't involved. 897 */ 898 static inline int PageTransCompound(const struct page *page) 899 { 900 return PageCompound(page); 901 } 902 903 /* 904 * PageTransTail returns true for both transparent huge pages 905 * and hugetlbfs pages, so it should only be called when it's known 906 * that hugetlbfs pages aren't involved. 907 */ 908 static inline int PageTransTail(const struct page *page) 909 { 910 return PageTail(page); 911 } 912 #else 913 TESTPAGEFLAG_FALSE(TransHuge, transhuge) 914 TESTPAGEFLAG_FALSE(TransCompound, transcompound) 915 TESTPAGEFLAG_FALSE(TransCompoundMap, transcompoundmap) 916 TESTPAGEFLAG_FALSE(TransTail, transtail) 917 #endif 918 919 #if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_TRANSPARENT_HUGEPAGE) 920 /* 921 * PageHasHWPoisoned indicates that at least one subpage is hwpoisoned in the 922 * compound page. 923 * 924 * This flag is set by hwpoison handler. Cleared by THP split or free page. 925 */ 926 PAGEFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND) 927 TESTSCFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND) 928 #else 929 PAGEFLAG_FALSE(HasHWPoisoned, has_hwpoisoned) 930 TESTSCFLAG_FALSE(HasHWPoisoned, has_hwpoisoned) 931 #endif 932 933 /* 934 * For pages that are never mapped to userspace (and aren't PageSlab), 935 * page_type may be used. Because it is initialised to -1, we invert the 936 * sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and 937 * __ClearPageFoo *sets* the bit used for PageFoo. We reserve a few high and 938 * low bits so that an underflow or overflow of _mapcount won't be 939 * mistaken for a page type value. 940 */ 941 942 #define PAGE_TYPE_BASE 0xf0000000 943 /* Reserve 0x0000007f to catch underflows of _mapcount */ 944 #define PAGE_MAPCOUNT_RESERVE -128 945 #define PG_buddy 0x00000080 946 #define PG_offline 0x00000100 947 #define PG_table 0x00000200 948 #define PG_guard 0x00000400 949 #define PG_hugetlb 0x00000800 950 951 #define PageType(page, flag) \ 952 ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE) 953 #define folio_test_type(folio, flag) \ 954 ((folio->page.page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE) 955 956 static inline int page_type_has_type(unsigned int page_type) 957 { 958 return (int)page_type < PAGE_MAPCOUNT_RESERVE; 959 } 960 961 static inline int page_has_type(const struct page *page) 962 { 963 return page_type_has_type(page->page_type); 964 } 965 966 #define FOLIO_TYPE_OPS(lname, fname) \ 967 static __always_inline bool folio_test_##fname(const struct folio *folio)\ 968 { \ 969 return folio_test_type(folio, PG_##lname); \ 970 } \ 971 static __always_inline void __folio_set_##fname(struct folio *folio) \ 972 { \ 973 VM_BUG_ON_FOLIO(!folio_test_type(folio, 0), folio); \ 974 folio->page.page_type &= ~PG_##lname; \ 975 } \ 976 static __always_inline void __folio_clear_##fname(struct folio *folio) \ 977 { \ 978 VM_BUG_ON_FOLIO(!folio_test_##fname(folio), folio); \ 979 folio->page.page_type |= PG_##lname; \ 980 } 981 982 #define PAGE_TYPE_OPS(uname, lname, fname) \ 983 FOLIO_TYPE_OPS(lname, fname) \ 984 static __always_inline int Page##uname(const struct page *page) \ 985 { \ 986 return PageType(page, PG_##lname); \ 987 } \ 988 static __always_inline void __SetPage##uname(struct page *page) \ 989 { \ 990 VM_BUG_ON_PAGE(!PageType(page, 0), page); \ 991 page->page_type &= ~PG_##lname; \ 992 } \ 993 static __always_inline void __ClearPage##uname(struct page *page) \ 994 { \ 995 VM_BUG_ON_PAGE(!Page##uname(page), page); \ 996 page->page_type |= PG_##lname; \ 997 } 998 999 /* 1000 * PageBuddy() indicates that the page is free and in the buddy system 1001 * (see mm/page_alloc.c). 1002 */ 1003 PAGE_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 * If a driver wants to allow to offline unmovable PageOffline() pages without 1013 * putting them back to the buddy, it can do so via the memory notifier by 1014 * decrementing the reference count in MEM_GOING_OFFLINE and incrementing the 1015 * reference count in MEM_CANCEL_OFFLINE. When offlining, the PageOffline() 1016 * pages (now with a reference count of zero) are treated like free pages, 1017 * allowing the containing memory block to get offlined. A driver that 1018 * relies on this feature is aware that re-onlining the memory block will 1019 * require to re-set the pages PageOffline() and not giving them to the 1020 * buddy via online_page_callback_t. 1021 * 1022 * There are drivers that mark a page PageOffline() and expect there won't be 1023 * any further access to page content. PFN walkers that read content of random 1024 * pages should check PageOffline() and synchronize with such drivers using 1025 * page_offline_freeze()/page_offline_thaw(). 1026 */ 1027 PAGE_TYPE_OPS(Offline, offline, offline) 1028 1029 extern void page_offline_freeze(void); 1030 extern void page_offline_thaw(void); 1031 extern void page_offline_begin(void); 1032 extern void page_offline_end(void); 1033 1034 /* 1035 * Marks pages in use as page tables. 1036 */ 1037 PAGE_TYPE_OPS(Table, table, pgtable) 1038 1039 /* 1040 * Marks guardpages used with debug_pagealloc. 1041 */ 1042 PAGE_TYPE_OPS(Guard, guard, guard) 1043 1044 #ifdef CONFIG_HUGETLB_PAGE 1045 FOLIO_TYPE_OPS(hugetlb, hugetlb) 1046 #else 1047 FOLIO_TEST_FLAG_FALSE(hugetlb) 1048 #endif 1049 1050 /** 1051 * PageHuge - Determine if the page belongs to hugetlbfs 1052 * @page: The page to test. 1053 * 1054 * Context: Any context. 1055 * Return: True for hugetlbfs pages, false for anon pages or pages 1056 * belonging to other filesystems. 1057 */ 1058 static inline bool PageHuge(const struct page *page) 1059 { 1060 return folio_test_hugetlb(page_folio(page)); 1061 } 1062 1063 /* 1064 * Check if a page is currently marked HWPoisoned. Note that this check is 1065 * best effort only and inherently racy: there is no way to synchronize with 1066 * failing hardware. 1067 */ 1068 static inline bool is_page_hwpoison(struct page *page) 1069 { 1070 if (PageHWPoison(page)) 1071 return true; 1072 return PageHuge(page) && PageHWPoison(compound_head(page)); 1073 } 1074 1075 extern bool is_free_buddy_page(struct page *page); 1076 1077 PAGEFLAG(Isolated, isolated, PF_ANY); 1078 1079 static __always_inline int PageAnonExclusive(const struct page *page) 1080 { 1081 VM_BUG_ON_PGFLAGS(!PageAnon(page), page); 1082 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); 1083 return test_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags); 1084 } 1085 1086 static __always_inline void SetPageAnonExclusive(struct page *page) 1087 { 1088 VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page); 1089 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); 1090 set_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags); 1091 } 1092 1093 static __always_inline void ClearPageAnonExclusive(struct page *page) 1094 { 1095 VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page); 1096 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); 1097 clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags); 1098 } 1099 1100 static __always_inline void __ClearPageAnonExclusive(struct page *page) 1101 { 1102 VM_BUG_ON_PGFLAGS(!PageAnon(page), page); 1103 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page); 1104 __clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags); 1105 } 1106 1107 #ifdef CONFIG_MMU 1108 #define __PG_MLOCKED (1UL << PG_mlocked) 1109 #else 1110 #define __PG_MLOCKED 0 1111 #endif 1112 1113 /* 1114 * Flags checked when a page is freed. Pages being freed should not have 1115 * these flags set. If they are, there is a problem. 1116 */ 1117 #define PAGE_FLAGS_CHECK_AT_FREE \ 1118 (1UL << PG_lru | 1UL << PG_locked | \ 1119 1UL << PG_private | 1UL << PG_private_2 | \ 1120 1UL << PG_writeback | 1UL << PG_reserved | \ 1121 1UL << PG_slab | 1UL << PG_active | \ 1122 1UL << PG_unevictable | __PG_MLOCKED | LRU_GEN_MASK) 1123 1124 /* 1125 * Flags checked when a page is prepped for return by the page allocator. 1126 * Pages being prepped should not have these flags set. If they are set, 1127 * there has been a kernel bug or struct page corruption. 1128 * 1129 * __PG_HWPOISON is exceptional because it needs to be kept beyond page's 1130 * alloc-free cycle to prevent from reusing the page. 1131 */ 1132 #define PAGE_FLAGS_CHECK_AT_PREP \ 1133 ((PAGEFLAGS_MASK & ~__PG_HWPOISON) | LRU_GEN_MASK | LRU_REFS_MASK) 1134 1135 /* 1136 * Flags stored in the second page of a compound page. They may overlap 1137 * the CHECK_AT_FREE flags above, so need to be cleared. 1138 */ 1139 #define PAGE_FLAGS_SECOND \ 1140 (0xffUL /* order */ | 1UL << PG_has_hwpoisoned | \ 1141 1UL << PG_large_rmappable) 1142 1143 #define PAGE_FLAGS_PRIVATE \ 1144 (1UL << PG_private | 1UL << PG_private_2) 1145 /** 1146 * page_has_private - Determine if page has private stuff 1147 * @page: The page to be checked 1148 * 1149 * Determine if a page has private stuff, indicating that release routines 1150 * should be invoked upon it. 1151 */ 1152 static inline int page_has_private(const struct page *page) 1153 { 1154 return !!(page->flags & PAGE_FLAGS_PRIVATE); 1155 } 1156 1157 static inline bool folio_has_private(const struct folio *folio) 1158 { 1159 return page_has_private(&folio->page); 1160 } 1161 1162 #undef PF_ANY 1163 #undef PF_HEAD 1164 #undef PF_NO_TAIL 1165 #undef PF_NO_COMPOUND 1166 #undef PF_SECOND 1167 #endif /* !__GENERATING_BOUNDS_H */ 1168 1169 #endif /* PAGE_FLAGS_H */ 1170