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_uptodate tells whether the page's contents is valid. When a read 67 * completes, the page becomes uptodate, unless a disk I/O error happened. 68 * 69 * PG_referenced, PG_reclaim are used for page reclaim for anonymous and 70 * file-backed pagecache (see mm/vmscan.c). 71 * 72 * PG_error is set to indicate that an I/O error occurred on this page. 73 * 74 * PG_arch_1 is an architecture specific page state bit. The generic code 75 * guarantees that this bit is cleared for a page when it first is entered into 76 * the page cache. 77 * 78 * PG_hwpoison indicates that a page got corrupted in hardware and contains 79 * data with incorrect ECC bits that triggered a machine check. Accessing is 80 * not safe since it may cause another machine check. Don't touch! 81 */ 82 83 /* 84 * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break 85 * locked- and dirty-page accounting. 86 * 87 * The page flags field is split into two parts, the main flags area 88 * which extends from the low bits upwards, and the fields area which 89 * extends from the high bits downwards. 90 * 91 * | FIELD | ... | FLAGS | 92 * N-1 ^ 0 93 * (NR_PAGEFLAGS) 94 * 95 * The fields area is reserved for fields mapping zone, node (for NUMA) and 96 * SPARSEMEM section (for variants of SPARSEMEM that require section ids like 97 * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP). 98 */ 99 enum pageflags { 100 PG_locked, /* Page is locked. Don't touch. */ 101 PG_referenced, 102 PG_uptodate, 103 PG_dirty, 104 PG_lru, 105 PG_active, 106 PG_workingset, 107 PG_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */ 108 PG_error, 109 PG_slab, 110 PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/ 111 PG_arch_1, 112 PG_reserved, 113 PG_private, /* If pagecache, has fs-private data */ 114 PG_private_2, /* If pagecache, has fs aux data */ 115 PG_writeback, /* Page is under writeback */ 116 PG_head, /* A head page */ 117 PG_mappedtodisk, /* Has blocks allocated on-disk */ 118 PG_reclaim, /* To be reclaimed asap */ 119 PG_swapbacked, /* Page is backed by RAM/swap */ 120 PG_unevictable, /* Page is "unevictable" */ 121 #ifdef CONFIG_MMU 122 PG_mlocked, /* Page is vma mlocked */ 123 #endif 124 #ifdef CONFIG_ARCH_USES_PG_UNCACHED 125 PG_uncached, /* Page has been mapped as uncached */ 126 #endif 127 #ifdef CONFIG_MEMORY_FAILURE 128 PG_hwpoison, /* hardware poisoned page. Don't touch */ 129 #endif 130 #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT) 131 PG_young, 132 PG_idle, 133 #endif 134 __NR_PAGEFLAGS, 135 136 /* Filesystems */ 137 PG_checked = PG_owner_priv_1, 138 139 /* SwapBacked */ 140 PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */ 141 142 /* Two page bits are conscripted by FS-Cache to maintain local caching 143 * state. These bits are set on pages belonging to the netfs's inodes 144 * when those inodes are being locally cached. 145 */ 146 PG_fscache = PG_private_2, /* page backed by cache */ 147 148 /* XEN */ 149 /* Pinned in Xen as a read-only pagetable page. */ 150 PG_pinned = PG_owner_priv_1, 151 /* Pinned as part of domain save (see xen_mm_pin_all()). */ 152 PG_savepinned = PG_dirty, 153 /* Has a grant mapping of another (foreign) domain's page. */ 154 PG_foreign = PG_owner_priv_1, 155 /* Remapped by swiotlb-xen. */ 156 PG_xen_remapped = PG_owner_priv_1, 157 158 /* SLOB */ 159 PG_slob_free = PG_private, 160 161 /* Compound pages. Stored in first tail page's flags */ 162 PG_double_map = PG_private_2, 163 164 /* non-lru isolated movable page */ 165 PG_isolated = PG_reclaim, 166 }; 167 168 #ifndef __GENERATING_BOUNDS_H 169 170 struct page; /* forward declaration */ 171 172 static inline struct page *compound_head(struct page *page) 173 { 174 unsigned long head = READ_ONCE(page->compound_head); 175 176 if (unlikely(head & 1)) 177 return (struct page *) (head - 1); 178 return page; 179 } 180 181 static __always_inline int PageTail(struct page *page) 182 { 183 return READ_ONCE(page->compound_head) & 1; 184 } 185 186 static __always_inline int PageCompound(struct page *page) 187 { 188 return test_bit(PG_head, &page->flags) || PageTail(page); 189 } 190 191 #define PAGE_POISON_PATTERN -1l 192 static inline int PagePoisoned(const struct page *page) 193 { 194 return page->flags == PAGE_POISON_PATTERN; 195 } 196 197 #ifdef CONFIG_DEBUG_VM 198 void page_init_poison(struct page *page, size_t size); 199 #else 200 static inline void page_init_poison(struct page *page, size_t size) 201 { 202 } 203 #endif 204 205 /* 206 * Page flags policies wrt compound pages 207 * 208 * PF_POISONED_CHECK 209 * check if this struct page poisoned/uninitialized 210 * 211 * PF_ANY: 212 * the page flag is relevant for small, head and tail pages. 213 * 214 * PF_HEAD: 215 * for compound page all operations related to the page flag applied to 216 * head page. 217 * 218 * PF_ONLY_HEAD: 219 * for compound page, callers only ever operate on the head page. 220 * 221 * PF_NO_TAIL: 222 * modifications of the page flag must be done on small or head pages, 223 * checks can be done on tail pages too. 224 * 225 * PF_NO_COMPOUND: 226 * the page flag is not relevant for compound pages. 227 */ 228 #define PF_POISONED_CHECK(page) ({ \ 229 VM_BUG_ON_PGFLAGS(PagePoisoned(page), page); \ 230 page; }) 231 #define PF_ANY(page, enforce) PF_POISONED_CHECK(page) 232 #define PF_HEAD(page, enforce) PF_POISONED_CHECK(compound_head(page)) 233 #define PF_ONLY_HEAD(page, enforce) ({ \ 234 VM_BUG_ON_PGFLAGS(PageTail(page), page); \ 235 PF_POISONED_CHECK(page); }) 236 #define PF_NO_TAIL(page, enforce) ({ \ 237 VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \ 238 PF_POISONED_CHECK(compound_head(page)); }) 239 #define PF_NO_COMPOUND(page, enforce) ({ \ 240 VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \ 241 PF_POISONED_CHECK(page); }) 242 243 /* 244 * Macros to create function definitions for page flags 245 */ 246 #define TESTPAGEFLAG(uname, lname, policy) \ 247 static __always_inline int Page##uname(struct page *page) \ 248 { return test_bit(PG_##lname, &policy(page, 0)->flags); } 249 250 #define SETPAGEFLAG(uname, lname, policy) \ 251 static __always_inline void SetPage##uname(struct page *page) \ 252 { set_bit(PG_##lname, &policy(page, 1)->flags); } 253 254 #define CLEARPAGEFLAG(uname, lname, policy) \ 255 static __always_inline void ClearPage##uname(struct page *page) \ 256 { clear_bit(PG_##lname, &policy(page, 1)->flags); } 257 258 #define __SETPAGEFLAG(uname, lname, policy) \ 259 static __always_inline void __SetPage##uname(struct page *page) \ 260 { __set_bit(PG_##lname, &policy(page, 1)->flags); } 261 262 #define __CLEARPAGEFLAG(uname, lname, policy) \ 263 static __always_inline void __ClearPage##uname(struct page *page) \ 264 { __clear_bit(PG_##lname, &policy(page, 1)->flags); } 265 266 #define TESTSETFLAG(uname, lname, policy) \ 267 static __always_inline int TestSetPage##uname(struct page *page) \ 268 { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); } 269 270 #define TESTCLEARFLAG(uname, lname, policy) \ 271 static __always_inline int TestClearPage##uname(struct page *page) \ 272 { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); } 273 274 #define PAGEFLAG(uname, lname, policy) \ 275 TESTPAGEFLAG(uname, lname, policy) \ 276 SETPAGEFLAG(uname, lname, policy) \ 277 CLEARPAGEFLAG(uname, lname, policy) 278 279 #define __PAGEFLAG(uname, lname, policy) \ 280 TESTPAGEFLAG(uname, lname, policy) \ 281 __SETPAGEFLAG(uname, lname, policy) \ 282 __CLEARPAGEFLAG(uname, lname, policy) 283 284 #define TESTSCFLAG(uname, lname, policy) \ 285 TESTSETFLAG(uname, lname, policy) \ 286 TESTCLEARFLAG(uname, lname, policy) 287 288 #define TESTPAGEFLAG_FALSE(uname) \ 289 static inline int Page##uname(const struct page *page) { return 0; } 290 291 #define SETPAGEFLAG_NOOP(uname) \ 292 static inline void SetPage##uname(struct page *page) { } 293 294 #define CLEARPAGEFLAG_NOOP(uname) \ 295 static inline void ClearPage##uname(struct page *page) { } 296 297 #define __CLEARPAGEFLAG_NOOP(uname) \ 298 static inline void __ClearPage##uname(struct page *page) { } 299 300 #define TESTSETFLAG_FALSE(uname) \ 301 static inline int TestSetPage##uname(struct page *page) { return 0; } 302 303 #define TESTCLEARFLAG_FALSE(uname) \ 304 static inline int TestClearPage##uname(struct page *page) { return 0; } 305 306 #define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \ 307 SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname) 308 309 #define TESTSCFLAG_FALSE(uname) \ 310 TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname) 311 312 __PAGEFLAG(Locked, locked, PF_NO_TAIL) 313 PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) __CLEARPAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) 314 PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND) 315 PAGEFLAG(Referenced, referenced, PF_HEAD) 316 TESTCLEARFLAG(Referenced, referenced, PF_HEAD) 317 __SETPAGEFLAG(Referenced, referenced, PF_HEAD) 318 PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD) 319 __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD) 320 PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD) 321 PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD) 322 TESTCLEARFLAG(Active, active, PF_HEAD) 323 PAGEFLAG(Workingset, workingset, PF_HEAD) 324 TESTCLEARFLAG(Workingset, workingset, PF_HEAD) 325 __PAGEFLAG(Slab, slab, PF_NO_TAIL) 326 __PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL) 327 PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */ 328 329 /* Xen */ 330 PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND) 331 TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND) 332 PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND); 333 PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND); 334 PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND) 335 TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND) 336 337 PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) 338 __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) 339 __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) 340 PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) 341 __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) 342 __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) 343 344 /* 345 * Private page markings that may be used by the filesystem that owns the page 346 * for its own purposes. 347 * - PG_private and PG_private_2 cause releasepage() and co to be invoked 348 */ 349 PAGEFLAG(Private, private, PF_ANY) __SETPAGEFLAG(Private, private, PF_ANY) 350 __CLEARPAGEFLAG(Private, private, PF_ANY) 351 PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY) 352 PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY) 353 TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY) 354 355 /* 356 * Only test-and-set exist for PG_writeback. The unconditional operators are 357 * risky: they bypass page accounting. 358 */ 359 TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL) 360 TESTSCFLAG(Writeback, writeback, PF_NO_TAIL) 361 PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL) 362 363 /* PG_readahead is only used for reads; PG_reclaim is only for writes */ 364 PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL) 365 TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL) 366 PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND) 367 TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND) 368 369 #ifdef CONFIG_HIGHMEM 370 /* 371 * Must use a macro here due to header dependency issues. page_zone() is not 372 * available at this point. 373 */ 374 #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p)) 375 #else 376 PAGEFLAG_FALSE(HighMem) 377 #endif 378 379 #ifdef CONFIG_SWAP 380 static __always_inline int PageSwapCache(struct page *page) 381 { 382 #ifdef CONFIG_THP_SWAP 383 page = compound_head(page); 384 #endif 385 return PageSwapBacked(page) && test_bit(PG_swapcache, &page->flags); 386 387 } 388 SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL) 389 CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL) 390 #else 391 PAGEFLAG_FALSE(SwapCache) 392 #endif 393 394 PAGEFLAG(Unevictable, unevictable, PF_HEAD) 395 __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD) 396 TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD) 397 398 #ifdef CONFIG_MMU 399 PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL) 400 __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL) 401 TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL) 402 #else 403 PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked) 404 TESTSCFLAG_FALSE(Mlocked) 405 #endif 406 407 #ifdef CONFIG_ARCH_USES_PG_UNCACHED 408 PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND) 409 #else 410 PAGEFLAG_FALSE(Uncached) 411 #endif 412 413 #ifdef CONFIG_MEMORY_FAILURE 414 PAGEFLAG(HWPoison, hwpoison, PF_ANY) 415 TESTSCFLAG(HWPoison, hwpoison, PF_ANY) 416 #define __PG_HWPOISON (1UL << PG_hwpoison) 417 extern bool set_hwpoison_free_buddy_page(struct page *page); 418 #else 419 PAGEFLAG_FALSE(HWPoison) 420 static inline bool set_hwpoison_free_buddy_page(struct page *page) 421 { 422 return 0; 423 } 424 #define __PG_HWPOISON 0 425 #endif 426 427 #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT) 428 TESTPAGEFLAG(Young, young, PF_ANY) 429 SETPAGEFLAG(Young, young, PF_ANY) 430 TESTCLEARFLAG(Young, young, PF_ANY) 431 PAGEFLAG(Idle, idle, PF_ANY) 432 #endif 433 434 /* 435 * On an anonymous page mapped into a user virtual memory area, 436 * page->mapping points to its anon_vma, not to a struct address_space; 437 * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h. 438 * 439 * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled, 440 * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON 441 * bit; and then page->mapping points, not to an anon_vma, but to a private 442 * structure which KSM associates with that merged page. See ksm.h. 443 * 444 * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable 445 * page and then page->mapping points a struct address_space. 446 * 447 * Please note that, confusingly, "page_mapping" refers to the inode 448 * address_space which maps the page from disk; whereas "page_mapped" 449 * refers to user virtual address space into which the page is mapped. 450 */ 451 #define PAGE_MAPPING_ANON 0x1 452 #define PAGE_MAPPING_MOVABLE 0x2 453 #define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE) 454 #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE) 455 456 static __always_inline int PageMappingFlags(struct page *page) 457 { 458 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0; 459 } 460 461 static __always_inline int PageAnon(struct page *page) 462 { 463 page = compound_head(page); 464 return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0; 465 } 466 467 static __always_inline int __PageMovable(struct page *page) 468 { 469 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == 470 PAGE_MAPPING_MOVABLE; 471 } 472 473 #ifdef CONFIG_KSM 474 /* 475 * A KSM page is one of those write-protected "shared pages" or "merged pages" 476 * which KSM maps into multiple mms, wherever identical anonymous page content 477 * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any 478 * anon_vma, but to that page's node of the stable tree. 479 */ 480 static __always_inline int PageKsm(struct page *page) 481 { 482 page = compound_head(page); 483 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == 484 PAGE_MAPPING_KSM; 485 } 486 #else 487 TESTPAGEFLAG_FALSE(Ksm) 488 #endif 489 490 u64 stable_page_flags(struct page *page); 491 492 static inline int PageUptodate(struct page *page) 493 { 494 int ret; 495 page = compound_head(page); 496 ret = test_bit(PG_uptodate, &(page)->flags); 497 /* 498 * Must ensure that the data we read out of the page is loaded 499 * _after_ we've loaded page->flags to check for PageUptodate. 500 * We can skip the barrier if the page is not uptodate, because 501 * we wouldn't be reading anything from it. 502 * 503 * See SetPageUptodate() for the other side of the story. 504 */ 505 if (ret) 506 smp_rmb(); 507 508 return ret; 509 } 510 511 static __always_inline void __SetPageUptodate(struct page *page) 512 { 513 VM_BUG_ON_PAGE(PageTail(page), page); 514 smp_wmb(); 515 __set_bit(PG_uptodate, &page->flags); 516 } 517 518 static __always_inline void SetPageUptodate(struct page *page) 519 { 520 VM_BUG_ON_PAGE(PageTail(page), page); 521 /* 522 * Memory barrier must be issued before setting the PG_uptodate bit, 523 * so that all previous stores issued in order to bring the page 524 * uptodate are actually visible before PageUptodate becomes true. 525 */ 526 smp_wmb(); 527 set_bit(PG_uptodate, &page->flags); 528 } 529 530 CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL) 531 532 int test_clear_page_writeback(struct page *page); 533 int __test_set_page_writeback(struct page *page, bool keep_write); 534 535 #define test_set_page_writeback(page) \ 536 __test_set_page_writeback(page, false) 537 #define test_set_page_writeback_keepwrite(page) \ 538 __test_set_page_writeback(page, true) 539 540 static inline void set_page_writeback(struct page *page) 541 { 542 test_set_page_writeback(page); 543 } 544 545 static inline void set_page_writeback_keepwrite(struct page *page) 546 { 547 test_set_page_writeback_keepwrite(page); 548 } 549 550 __PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY) 551 552 static __always_inline void set_compound_head(struct page *page, struct page *head) 553 { 554 WRITE_ONCE(page->compound_head, (unsigned long)head + 1); 555 } 556 557 static __always_inline void clear_compound_head(struct page *page) 558 { 559 WRITE_ONCE(page->compound_head, 0); 560 } 561 562 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 563 static inline void ClearPageCompound(struct page *page) 564 { 565 BUG_ON(!PageHead(page)); 566 ClearPageHead(page); 567 } 568 #endif 569 570 #define PG_head_mask ((1UL << PG_head)) 571 572 #ifdef CONFIG_HUGETLB_PAGE 573 int PageHuge(struct page *page); 574 int PageHeadHuge(struct page *page); 575 bool page_huge_active(struct page *page); 576 #else 577 TESTPAGEFLAG_FALSE(Huge) 578 TESTPAGEFLAG_FALSE(HeadHuge) 579 580 static inline bool page_huge_active(struct page *page) 581 { 582 return 0; 583 } 584 #endif 585 586 587 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 588 /* 589 * PageHuge() only returns true for hugetlbfs pages, but not for 590 * normal or transparent huge pages. 591 * 592 * PageTransHuge() returns true for both transparent huge and 593 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be 594 * called only in the core VM paths where hugetlbfs pages can't exist. 595 */ 596 static inline int PageTransHuge(struct page *page) 597 { 598 VM_BUG_ON_PAGE(PageTail(page), page); 599 return PageHead(page); 600 } 601 602 /* 603 * PageTransCompound returns true for both transparent huge pages 604 * and hugetlbfs pages, so it should only be called when it's known 605 * that hugetlbfs pages aren't involved. 606 */ 607 static inline int PageTransCompound(struct page *page) 608 { 609 return PageCompound(page); 610 } 611 612 /* 613 * PageTransCompoundMap is the same as PageTransCompound, but it also 614 * guarantees the primary MMU has the entire compound page mapped 615 * through pmd_trans_huge, which in turn guarantees the secondary MMUs 616 * can also map the entire compound page. This allows the secondary 617 * MMUs to call get_user_pages() only once for each compound page and 618 * to immediately map the entire compound page with a single secondary 619 * MMU fault. If there will be a pmd split later, the secondary MMUs 620 * will get an update through the MMU notifier invalidation through 621 * split_huge_pmd(). 622 * 623 * Unlike PageTransCompound, this is safe to be called only while 624 * split_huge_pmd() cannot run from under us, like if protected by the 625 * MMU notifier, otherwise it may result in page->_mapcount check false 626 * positives. 627 * 628 * We have to treat page cache THP differently since every subpage of it 629 * would get _mapcount inc'ed once it is PMD mapped. But, it may be PTE 630 * mapped in the current process so comparing subpage's _mapcount to 631 * compound_mapcount to filter out PTE mapped case. 632 */ 633 static inline int PageTransCompoundMap(struct page *page) 634 { 635 struct page *head; 636 637 if (!PageTransCompound(page)) 638 return 0; 639 640 if (PageAnon(page)) 641 return atomic_read(&page->_mapcount) < 0; 642 643 head = compound_head(page); 644 /* File THP is PMD mapped and not PTE mapped */ 645 return atomic_read(&page->_mapcount) == 646 atomic_read(compound_mapcount_ptr(head)); 647 } 648 649 /* 650 * PageTransTail returns true for both transparent huge pages 651 * and hugetlbfs pages, so it should only be called when it's known 652 * that hugetlbfs pages aren't involved. 653 */ 654 static inline int PageTransTail(struct page *page) 655 { 656 return PageTail(page); 657 } 658 659 /* 660 * PageDoubleMap indicates that the compound page is mapped with PTEs as well 661 * as PMDs. 662 * 663 * This is required for optimization of rmap operations for THP: we can postpone 664 * per small page mapcount accounting (and its overhead from atomic operations) 665 * until the first PMD split. 666 * 667 * For the page PageDoubleMap means ->_mapcount in all sub-pages is offset up 668 * by one. This reference will go away with last compound_mapcount. 669 * 670 * See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap(). 671 */ 672 static inline int PageDoubleMap(struct page *page) 673 { 674 return PageHead(page) && test_bit(PG_double_map, &page[1].flags); 675 } 676 677 static inline void SetPageDoubleMap(struct page *page) 678 { 679 VM_BUG_ON_PAGE(!PageHead(page), page); 680 set_bit(PG_double_map, &page[1].flags); 681 } 682 683 static inline void ClearPageDoubleMap(struct page *page) 684 { 685 VM_BUG_ON_PAGE(!PageHead(page), page); 686 clear_bit(PG_double_map, &page[1].flags); 687 } 688 static inline int TestSetPageDoubleMap(struct page *page) 689 { 690 VM_BUG_ON_PAGE(!PageHead(page), page); 691 return test_and_set_bit(PG_double_map, &page[1].flags); 692 } 693 694 static inline int TestClearPageDoubleMap(struct page *page) 695 { 696 VM_BUG_ON_PAGE(!PageHead(page), page); 697 return test_and_clear_bit(PG_double_map, &page[1].flags); 698 } 699 700 #else 701 TESTPAGEFLAG_FALSE(TransHuge) 702 TESTPAGEFLAG_FALSE(TransCompound) 703 TESTPAGEFLAG_FALSE(TransCompoundMap) 704 TESTPAGEFLAG_FALSE(TransTail) 705 PAGEFLAG_FALSE(DoubleMap) 706 TESTSETFLAG_FALSE(DoubleMap) 707 TESTCLEARFLAG_FALSE(DoubleMap) 708 #endif 709 710 /* 711 * For pages that are never mapped to userspace (and aren't PageSlab), 712 * page_type may be used. Because it is initialised to -1, we invert the 713 * sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and 714 * __ClearPageFoo *sets* the bit used for PageFoo. We reserve a few high and 715 * low bits so that an underflow or overflow of page_mapcount() won't be 716 * mistaken for a page type value. 717 */ 718 719 #define PAGE_TYPE_BASE 0xf0000000 720 /* Reserve 0x0000007f to catch underflows of page_mapcount */ 721 #define PAGE_MAPCOUNT_RESERVE -128 722 #define PG_buddy 0x00000080 723 #define PG_offline 0x00000100 724 #define PG_kmemcg 0x00000200 725 #define PG_table 0x00000400 726 #define PG_guard 0x00000800 727 728 #define PageType(page, flag) \ 729 ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE) 730 731 static inline int page_has_type(struct page *page) 732 { 733 return (int)page->page_type < PAGE_MAPCOUNT_RESERVE; 734 } 735 736 #define PAGE_TYPE_OPS(uname, lname) \ 737 static __always_inline int Page##uname(struct page *page) \ 738 { \ 739 return PageType(page, PG_##lname); \ 740 } \ 741 static __always_inline void __SetPage##uname(struct page *page) \ 742 { \ 743 VM_BUG_ON_PAGE(!PageType(page, 0), page); \ 744 page->page_type &= ~PG_##lname; \ 745 } \ 746 static __always_inline void __ClearPage##uname(struct page *page) \ 747 { \ 748 VM_BUG_ON_PAGE(!Page##uname(page), page); \ 749 page->page_type |= PG_##lname; \ 750 } 751 752 /* 753 * PageBuddy() indicates that the page is free and in the buddy system 754 * (see mm/page_alloc.c). 755 */ 756 PAGE_TYPE_OPS(Buddy, buddy) 757 758 /* 759 * PageOffline() indicates that the page is logically offline although the 760 * containing section is online. (e.g. inflated in a balloon driver or 761 * not onlined when onlining the section). 762 * The content of these pages is effectively stale. Such pages should not 763 * be touched (read/write/dump/save) except by their owner. 764 */ 765 PAGE_TYPE_OPS(Offline, offline) 766 767 /* 768 * If kmemcg is enabled, the buddy allocator will set PageKmemcg() on 769 * pages allocated with __GFP_ACCOUNT. It gets cleared on page free. 770 */ 771 PAGE_TYPE_OPS(Kmemcg, kmemcg) 772 773 /* 774 * Marks pages in use as page tables. 775 */ 776 PAGE_TYPE_OPS(Table, table) 777 778 /* 779 * Marks guardpages used with debug_pagealloc. 780 */ 781 PAGE_TYPE_OPS(Guard, guard) 782 783 extern bool is_free_buddy_page(struct page *page); 784 785 __PAGEFLAG(Isolated, isolated, PF_ANY); 786 787 /* 788 * If network-based swap is enabled, sl*b must keep track of whether pages 789 * were allocated from pfmemalloc reserves. 790 */ 791 static inline int PageSlabPfmemalloc(struct page *page) 792 { 793 VM_BUG_ON_PAGE(!PageSlab(page), page); 794 return PageActive(page); 795 } 796 797 static inline void SetPageSlabPfmemalloc(struct page *page) 798 { 799 VM_BUG_ON_PAGE(!PageSlab(page), page); 800 SetPageActive(page); 801 } 802 803 static inline void __ClearPageSlabPfmemalloc(struct page *page) 804 { 805 VM_BUG_ON_PAGE(!PageSlab(page), page); 806 __ClearPageActive(page); 807 } 808 809 static inline void ClearPageSlabPfmemalloc(struct page *page) 810 { 811 VM_BUG_ON_PAGE(!PageSlab(page), page); 812 ClearPageActive(page); 813 } 814 815 #ifdef CONFIG_MMU 816 #define __PG_MLOCKED (1UL << PG_mlocked) 817 #else 818 #define __PG_MLOCKED 0 819 #endif 820 821 /* 822 * Flags checked when a page is freed. Pages being freed should not have 823 * these flags set. It they are, there is a problem. 824 */ 825 #define PAGE_FLAGS_CHECK_AT_FREE \ 826 (1UL << PG_lru | 1UL << PG_locked | \ 827 1UL << PG_private | 1UL << PG_private_2 | \ 828 1UL << PG_writeback | 1UL << PG_reserved | \ 829 1UL << PG_slab | 1UL << PG_active | \ 830 1UL << PG_unevictable | __PG_MLOCKED) 831 832 /* 833 * Flags checked when a page is prepped for return by the page allocator. 834 * Pages being prepped should not have these flags set. It they are set, 835 * there has been a kernel bug or struct page corruption. 836 * 837 * __PG_HWPOISON is exceptional because it needs to be kept beyond page's 838 * alloc-free cycle to prevent from reusing the page. 839 */ 840 #define PAGE_FLAGS_CHECK_AT_PREP \ 841 (((1UL << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON) 842 843 #define PAGE_FLAGS_PRIVATE \ 844 (1UL << PG_private | 1UL << PG_private_2) 845 /** 846 * page_has_private - Determine if page has private stuff 847 * @page: The page to be checked 848 * 849 * Determine if a page has private stuff, indicating that release routines 850 * should be invoked upon it. 851 */ 852 static inline int page_has_private(struct page *page) 853 { 854 return !!(page->flags & PAGE_FLAGS_PRIVATE); 855 } 856 857 #undef PF_ANY 858 #undef PF_HEAD 859 #undef PF_ONLY_HEAD 860 #undef PF_NO_TAIL 861 #undef PF_NO_COMPOUND 862 #endif /* !__GENERATING_BOUNDS_H */ 863 864 #endif /* PAGE_FLAGS_H */ 865