1 /* 2 * Macros for manipulating and testing page->flags 3 */ 4 5 #ifndef PAGE_FLAGS_H 6 #define PAGE_FLAGS_H 7 8 #include <linux/types.h> 9 #include <linux/bug.h> 10 #include <linux/mmdebug.h> 11 #ifndef __GENERATING_BOUNDS_H 12 #include <linux/mm_types.h> 13 #include <generated/bounds.h> 14 #endif /* !__GENERATING_BOUNDS_H */ 15 16 /* 17 * Various page->flags bits: 18 * 19 * PG_reserved is set for special pages, which can never be swapped out. Some 20 * of them might not even exist (eg empty_bad_page)... 21 * 22 * The PG_private bitflag is set on pagecache pages if they contain filesystem 23 * specific data (which is normally at page->private). It can be used by 24 * private allocations for its own usage. 25 * 26 * During initiation of disk I/O, PG_locked is set. This bit is set before I/O 27 * and cleared when writeback _starts_ or when read _completes_. PG_writeback 28 * is set before writeback starts and cleared when it finishes. 29 * 30 * PG_locked also pins a page in pagecache, and blocks truncation of the file 31 * while it is held. 32 * 33 * page_waitqueue(page) is a wait queue of all tasks waiting for the page 34 * to become unlocked. 35 * 36 * PG_uptodate tells whether the page's contents is valid. When a read 37 * completes, the page becomes uptodate, unless a disk I/O error happened. 38 * 39 * PG_referenced, PG_reclaim are used for page reclaim for anonymous and 40 * file-backed pagecache (see mm/vmscan.c). 41 * 42 * PG_error is set to indicate that an I/O error occurred on this page. 43 * 44 * PG_arch_1 is an architecture specific page state bit. The generic code 45 * guarantees that this bit is cleared for a page when it first is entered into 46 * the page cache. 47 * 48 * PG_highmem pages are not permanently mapped into the kernel virtual address 49 * space, they need to be kmapped separately for doing IO on the pages. The 50 * struct page (these bits with information) are always mapped into kernel 51 * address space... 52 * 53 * PG_hwpoison indicates that a page got corrupted in hardware and contains 54 * data with incorrect ECC bits that triggered a machine check. Accessing is 55 * not safe since it may cause another machine check. Don't touch! 56 */ 57 58 /* 59 * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break 60 * locked- and dirty-page accounting. 61 * 62 * The page flags field is split into two parts, the main flags area 63 * which extends from the low bits upwards, and the fields area which 64 * extends from the high bits downwards. 65 * 66 * | FIELD | ... | FLAGS | 67 * N-1 ^ 0 68 * (NR_PAGEFLAGS) 69 * 70 * The fields area is reserved for fields mapping zone, node (for NUMA) and 71 * SPARSEMEM section (for variants of SPARSEMEM that require section ids like 72 * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP). 73 */ 74 enum pageflags { 75 PG_locked, /* Page is locked. Don't touch. */ 76 PG_error, 77 PG_referenced, 78 PG_uptodate, 79 PG_dirty, 80 PG_lru, 81 PG_active, 82 PG_slab, 83 PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/ 84 PG_arch_1, 85 PG_reserved, 86 PG_private, /* If pagecache, has fs-private data */ 87 PG_private_2, /* If pagecache, has fs aux data */ 88 PG_writeback, /* Page is under writeback */ 89 #ifdef CONFIG_PAGEFLAGS_EXTENDED 90 PG_head, /* A head page */ 91 PG_tail, /* A tail page */ 92 #else 93 PG_compound, /* A compound page */ 94 #endif 95 PG_swapcache, /* Swap page: swp_entry_t in private */ 96 PG_mappedtodisk, /* Has blocks allocated on-disk */ 97 PG_reclaim, /* To be reclaimed asap */ 98 PG_swapbacked, /* Page is backed by RAM/swap */ 99 PG_unevictable, /* Page is "unevictable" */ 100 #ifdef CONFIG_MMU 101 PG_mlocked, /* Page is vma mlocked */ 102 #endif 103 #ifdef CONFIG_ARCH_USES_PG_UNCACHED 104 PG_uncached, /* Page has been mapped as uncached */ 105 #endif 106 #ifdef CONFIG_MEMORY_FAILURE 107 PG_hwpoison, /* hardware poisoned page. Don't touch */ 108 #endif 109 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 110 PG_compound_lock, 111 #endif 112 #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT) 113 PG_young, 114 PG_idle, 115 #endif 116 __NR_PAGEFLAGS, 117 118 /* Filesystems */ 119 PG_checked = PG_owner_priv_1, 120 121 /* Two page bits are conscripted by FS-Cache to maintain local caching 122 * state. These bits are set on pages belonging to the netfs's inodes 123 * when those inodes are being locally cached. 124 */ 125 PG_fscache = PG_private_2, /* page backed by cache */ 126 127 /* XEN */ 128 /* Pinned in Xen as a read-only pagetable page. */ 129 PG_pinned = PG_owner_priv_1, 130 /* Pinned as part of domain save (see xen_mm_pin_all()). */ 131 PG_savepinned = PG_dirty, 132 /* Has a grant mapping of another (foreign) domain's page. */ 133 PG_foreign = PG_owner_priv_1, 134 135 /* SLOB */ 136 PG_slob_free = PG_private, 137 }; 138 139 #ifndef __GENERATING_BOUNDS_H 140 141 /* 142 * Macros to create function definitions for page flags 143 */ 144 #define TESTPAGEFLAG(uname, lname) \ 145 static inline int Page##uname(const struct page *page) \ 146 { return test_bit(PG_##lname, &page->flags); } 147 148 #define SETPAGEFLAG(uname, lname) \ 149 static inline void SetPage##uname(struct page *page) \ 150 { set_bit(PG_##lname, &page->flags); } 151 152 #define CLEARPAGEFLAG(uname, lname) \ 153 static inline void ClearPage##uname(struct page *page) \ 154 { clear_bit(PG_##lname, &page->flags); } 155 156 #define __SETPAGEFLAG(uname, lname) \ 157 static inline void __SetPage##uname(struct page *page) \ 158 { __set_bit(PG_##lname, &page->flags); } 159 160 #define __CLEARPAGEFLAG(uname, lname) \ 161 static inline void __ClearPage##uname(struct page *page) \ 162 { __clear_bit(PG_##lname, &page->flags); } 163 164 #define TESTSETFLAG(uname, lname) \ 165 static inline int TestSetPage##uname(struct page *page) \ 166 { return test_and_set_bit(PG_##lname, &page->flags); } 167 168 #define TESTCLEARFLAG(uname, lname) \ 169 static inline int TestClearPage##uname(struct page *page) \ 170 { return test_and_clear_bit(PG_##lname, &page->flags); } 171 172 #define __TESTCLEARFLAG(uname, lname) \ 173 static inline int __TestClearPage##uname(struct page *page) \ 174 { return __test_and_clear_bit(PG_##lname, &page->flags); } 175 176 #define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \ 177 SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname) 178 179 #define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \ 180 __SETPAGEFLAG(uname, lname) __CLEARPAGEFLAG(uname, lname) 181 182 #define TESTSCFLAG(uname, lname) \ 183 TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname) 184 185 #define TESTPAGEFLAG_FALSE(uname) \ 186 static inline int Page##uname(const struct page *page) { return 0; } 187 188 #define SETPAGEFLAG_NOOP(uname) \ 189 static inline void SetPage##uname(struct page *page) { } 190 191 #define CLEARPAGEFLAG_NOOP(uname) \ 192 static inline void ClearPage##uname(struct page *page) { } 193 194 #define __CLEARPAGEFLAG_NOOP(uname) \ 195 static inline void __ClearPage##uname(struct page *page) { } 196 197 #define TESTSETFLAG_FALSE(uname) \ 198 static inline int TestSetPage##uname(struct page *page) { return 0; } 199 200 #define TESTCLEARFLAG_FALSE(uname) \ 201 static inline int TestClearPage##uname(struct page *page) { return 0; } 202 203 #define __TESTCLEARFLAG_FALSE(uname) \ 204 static inline int __TestClearPage##uname(struct page *page) { return 0; } 205 206 #define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \ 207 SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname) 208 209 #define TESTSCFLAG_FALSE(uname) \ 210 TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname) 211 212 struct page; /* forward declaration */ 213 214 TESTPAGEFLAG(Locked, locked) 215 PAGEFLAG(Error, error) TESTCLEARFLAG(Error, error) 216 PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced) 217 __SETPAGEFLAG(Referenced, referenced) 218 PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty) 219 PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru) 220 PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active) 221 TESTCLEARFLAG(Active, active) 222 __PAGEFLAG(Slab, slab) 223 PAGEFLAG(Checked, checked) /* Used by some filesystems */ 224 PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */ 225 PAGEFLAG(SavePinned, savepinned); /* Xen */ 226 PAGEFLAG(Foreign, foreign); /* Xen */ 227 PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved) 228 PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked) 229 __SETPAGEFLAG(SwapBacked, swapbacked) 230 231 __PAGEFLAG(SlobFree, slob_free) 232 233 /* 234 * Private page markings that may be used by the filesystem that owns the page 235 * for its own purposes. 236 * - PG_private and PG_private_2 cause releasepage() and co to be invoked 237 */ 238 PAGEFLAG(Private, private) __SETPAGEFLAG(Private, private) 239 __CLEARPAGEFLAG(Private, private) 240 PAGEFLAG(Private2, private_2) TESTSCFLAG(Private2, private_2) 241 PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1) 242 243 /* 244 * Only test-and-set exist for PG_writeback. The unconditional operators are 245 * risky: they bypass page accounting. 246 */ 247 TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback) 248 PAGEFLAG(MappedToDisk, mappedtodisk) 249 250 /* PG_readahead is only used for reads; PG_reclaim is only for writes */ 251 PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim) 252 PAGEFLAG(Readahead, reclaim) TESTCLEARFLAG(Readahead, reclaim) 253 254 #ifdef CONFIG_HIGHMEM 255 /* 256 * Must use a macro here due to header dependency issues. page_zone() is not 257 * available at this point. 258 */ 259 #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p)) 260 #else 261 PAGEFLAG_FALSE(HighMem) 262 #endif 263 264 #ifdef CONFIG_SWAP 265 PAGEFLAG(SwapCache, swapcache) 266 #else 267 PAGEFLAG_FALSE(SwapCache) 268 #endif 269 270 PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable) 271 TESTCLEARFLAG(Unevictable, unevictable) 272 273 #ifdef CONFIG_MMU 274 PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked) 275 TESTSCFLAG(Mlocked, mlocked) __TESTCLEARFLAG(Mlocked, mlocked) 276 #else 277 PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked) 278 TESTSCFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked) 279 #endif 280 281 #ifdef CONFIG_ARCH_USES_PG_UNCACHED 282 PAGEFLAG(Uncached, uncached) 283 #else 284 PAGEFLAG_FALSE(Uncached) 285 #endif 286 287 #ifdef CONFIG_MEMORY_FAILURE 288 PAGEFLAG(HWPoison, hwpoison) 289 TESTSCFLAG(HWPoison, hwpoison) 290 #define __PG_HWPOISON (1UL << PG_hwpoison) 291 #else 292 PAGEFLAG_FALSE(HWPoison) 293 #define __PG_HWPOISON 0 294 #endif 295 296 #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT) 297 TESTPAGEFLAG(Young, young) 298 SETPAGEFLAG(Young, young) 299 TESTCLEARFLAG(Young, young) 300 PAGEFLAG(Idle, idle) 301 #endif 302 303 /* 304 * On an anonymous page mapped into a user virtual memory area, 305 * page->mapping points to its anon_vma, not to a struct address_space; 306 * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h. 307 * 308 * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled, 309 * the PAGE_MAPPING_KSM bit may be set along with the PAGE_MAPPING_ANON bit; 310 * and then page->mapping points, not to an anon_vma, but to a private 311 * structure which KSM associates with that merged page. See ksm.h. 312 * 313 * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is currently never used. 314 * 315 * Please note that, confusingly, "page_mapping" refers to the inode 316 * address_space which maps the page from disk; whereas "page_mapped" 317 * refers to user virtual address space into which the page is mapped. 318 */ 319 #define PAGE_MAPPING_ANON 1 320 #define PAGE_MAPPING_KSM 2 321 #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM) 322 323 static inline int PageAnon(struct page *page) 324 { 325 return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0; 326 } 327 328 #ifdef CONFIG_KSM 329 /* 330 * A KSM page is one of those write-protected "shared pages" or "merged pages" 331 * which KSM maps into multiple mms, wherever identical anonymous page content 332 * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any 333 * anon_vma, but to that page's node of the stable tree. 334 */ 335 static inline int PageKsm(struct page *page) 336 { 337 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == 338 (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM); 339 } 340 #else 341 TESTPAGEFLAG_FALSE(Ksm) 342 #endif 343 344 u64 stable_page_flags(struct page *page); 345 346 static inline int PageUptodate(struct page *page) 347 { 348 int ret = test_bit(PG_uptodate, &(page)->flags); 349 350 /* 351 * Must ensure that the data we read out of the page is loaded 352 * _after_ we've loaded page->flags to check for PageUptodate. 353 * We can skip the barrier if the page is not uptodate, because 354 * we wouldn't be reading anything from it. 355 * 356 * See SetPageUptodate() for the other side of the story. 357 */ 358 if (ret) 359 smp_rmb(); 360 361 return ret; 362 } 363 364 static inline void __SetPageUptodate(struct page *page) 365 { 366 smp_wmb(); 367 __set_bit(PG_uptodate, &(page)->flags); 368 } 369 370 static inline void SetPageUptodate(struct page *page) 371 { 372 /* 373 * Memory barrier must be issued before setting the PG_uptodate bit, 374 * so that all previous stores issued in order to bring the page 375 * uptodate are actually visible before PageUptodate becomes true. 376 */ 377 smp_wmb(); 378 set_bit(PG_uptodate, &(page)->flags); 379 } 380 381 CLEARPAGEFLAG(Uptodate, uptodate) 382 383 int test_clear_page_writeback(struct page *page); 384 int __test_set_page_writeback(struct page *page, bool keep_write); 385 386 #define test_set_page_writeback(page) \ 387 __test_set_page_writeback(page, false) 388 #define test_set_page_writeback_keepwrite(page) \ 389 __test_set_page_writeback(page, true) 390 391 static inline void set_page_writeback(struct page *page) 392 { 393 test_set_page_writeback(page); 394 } 395 396 static inline void set_page_writeback_keepwrite(struct page *page) 397 { 398 test_set_page_writeback_keepwrite(page); 399 } 400 401 #ifdef CONFIG_PAGEFLAGS_EXTENDED 402 /* 403 * System with lots of page flags available. This allows separate 404 * flags for PageHead() and PageTail() checks of compound pages so that bit 405 * tests can be used in performance sensitive paths. PageCompound is 406 * generally not used in hot code paths except arch/powerpc/mm/init_64.c 407 * and arch/powerpc/kvm/book3s_64_vio_hv.c which use it to detect huge pages 408 * and avoid handling those in real mode. 409 */ 410 __PAGEFLAG(Head, head) CLEARPAGEFLAG(Head, head) 411 __PAGEFLAG(Tail, tail) 412 413 static inline int PageCompound(struct page *page) 414 { 415 return page->flags & ((1L << PG_head) | (1L << PG_tail)); 416 417 } 418 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 419 static inline void ClearPageCompound(struct page *page) 420 { 421 BUG_ON(!PageHead(page)); 422 ClearPageHead(page); 423 } 424 #endif 425 426 #define PG_head_mask ((1L << PG_head)) 427 428 #else 429 /* 430 * Reduce page flag use as much as possible by overlapping 431 * compound page flags with the flags used for page cache pages. Possible 432 * because PageCompound is always set for compound pages and not for 433 * pages on the LRU and/or pagecache. 434 */ 435 TESTPAGEFLAG(Compound, compound) 436 __SETPAGEFLAG(Head, compound) __CLEARPAGEFLAG(Head, compound) 437 438 /* 439 * PG_reclaim is used in combination with PG_compound to mark the 440 * head and tail of a compound page. This saves one page flag 441 * but makes it impossible to use compound pages for the page cache. 442 * The PG_reclaim bit would have to be used for reclaim or readahead 443 * if compound pages enter the page cache. 444 * 445 * PG_compound & PG_reclaim => Tail page 446 * PG_compound & ~PG_reclaim => Head page 447 */ 448 #define PG_head_mask ((1L << PG_compound)) 449 #define PG_head_tail_mask ((1L << PG_compound) | (1L << PG_reclaim)) 450 451 static inline int PageHead(struct page *page) 452 { 453 return ((page->flags & PG_head_tail_mask) == PG_head_mask); 454 } 455 456 static inline int PageTail(struct page *page) 457 { 458 return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask); 459 } 460 461 static inline void __SetPageTail(struct page *page) 462 { 463 page->flags |= PG_head_tail_mask; 464 } 465 466 static inline void __ClearPageTail(struct page *page) 467 { 468 page->flags &= ~PG_head_tail_mask; 469 } 470 471 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 472 static inline void ClearPageCompound(struct page *page) 473 { 474 BUG_ON((page->flags & PG_head_tail_mask) != (1 << PG_compound)); 475 clear_bit(PG_compound, &page->flags); 476 } 477 #endif 478 479 #endif /* !PAGEFLAGS_EXTENDED */ 480 481 #ifdef CONFIG_HUGETLB_PAGE 482 int PageHuge(struct page *page); 483 int PageHeadHuge(struct page *page); 484 bool page_huge_active(struct page *page); 485 #else 486 TESTPAGEFLAG_FALSE(Huge) 487 TESTPAGEFLAG_FALSE(HeadHuge) 488 489 static inline bool page_huge_active(struct page *page) 490 { 491 return 0; 492 } 493 #endif 494 495 496 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 497 /* 498 * PageHuge() only returns true for hugetlbfs pages, but not for 499 * normal or transparent huge pages. 500 * 501 * PageTransHuge() returns true for both transparent huge and 502 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be 503 * called only in the core VM paths where hugetlbfs pages can't exist. 504 */ 505 static inline int PageTransHuge(struct page *page) 506 { 507 VM_BUG_ON_PAGE(PageTail(page), page); 508 return PageHead(page); 509 } 510 511 /* 512 * PageTransCompound returns true for both transparent huge pages 513 * and hugetlbfs pages, so it should only be called when it's known 514 * that hugetlbfs pages aren't involved. 515 */ 516 static inline int PageTransCompound(struct page *page) 517 { 518 return PageCompound(page); 519 } 520 521 /* 522 * PageTransTail returns true for both transparent huge pages 523 * and hugetlbfs pages, so it should only be called when it's known 524 * that hugetlbfs pages aren't involved. 525 */ 526 static inline int PageTransTail(struct page *page) 527 { 528 return PageTail(page); 529 } 530 531 #else 532 533 static inline int PageTransHuge(struct page *page) 534 { 535 return 0; 536 } 537 538 static inline int PageTransCompound(struct page *page) 539 { 540 return 0; 541 } 542 543 static inline int PageTransTail(struct page *page) 544 { 545 return 0; 546 } 547 #endif 548 549 /* 550 * PageBuddy() indicate that the page is free and in the buddy system 551 * (see mm/page_alloc.c). 552 * 553 * PAGE_BUDDY_MAPCOUNT_VALUE must be <= -2 but better not too close to 554 * -2 so that an underflow of the page_mapcount() won't be mistaken 555 * for a genuine PAGE_BUDDY_MAPCOUNT_VALUE. -128 can be created very 556 * efficiently by most CPU architectures. 557 */ 558 #define PAGE_BUDDY_MAPCOUNT_VALUE (-128) 559 560 static inline int PageBuddy(struct page *page) 561 { 562 return atomic_read(&page->_mapcount) == PAGE_BUDDY_MAPCOUNT_VALUE; 563 } 564 565 static inline void __SetPageBuddy(struct page *page) 566 { 567 VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page); 568 atomic_set(&page->_mapcount, PAGE_BUDDY_MAPCOUNT_VALUE); 569 } 570 571 static inline void __ClearPageBuddy(struct page *page) 572 { 573 VM_BUG_ON_PAGE(!PageBuddy(page), page); 574 atomic_set(&page->_mapcount, -1); 575 } 576 577 #define PAGE_BALLOON_MAPCOUNT_VALUE (-256) 578 579 static inline int PageBalloon(struct page *page) 580 { 581 return atomic_read(&page->_mapcount) == PAGE_BALLOON_MAPCOUNT_VALUE; 582 } 583 584 static inline void __SetPageBalloon(struct page *page) 585 { 586 VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page); 587 atomic_set(&page->_mapcount, PAGE_BALLOON_MAPCOUNT_VALUE); 588 } 589 590 static inline void __ClearPageBalloon(struct page *page) 591 { 592 VM_BUG_ON_PAGE(!PageBalloon(page), page); 593 atomic_set(&page->_mapcount, -1); 594 } 595 596 /* 597 * If network-based swap is enabled, sl*b must keep track of whether pages 598 * were allocated from pfmemalloc reserves. 599 */ 600 static inline int PageSlabPfmemalloc(struct page *page) 601 { 602 VM_BUG_ON_PAGE(!PageSlab(page), page); 603 return PageActive(page); 604 } 605 606 static inline void SetPageSlabPfmemalloc(struct page *page) 607 { 608 VM_BUG_ON_PAGE(!PageSlab(page), page); 609 SetPageActive(page); 610 } 611 612 static inline void __ClearPageSlabPfmemalloc(struct page *page) 613 { 614 VM_BUG_ON_PAGE(!PageSlab(page), page); 615 __ClearPageActive(page); 616 } 617 618 static inline void ClearPageSlabPfmemalloc(struct page *page) 619 { 620 VM_BUG_ON_PAGE(!PageSlab(page), page); 621 ClearPageActive(page); 622 } 623 624 #ifdef CONFIG_MMU 625 #define __PG_MLOCKED (1 << PG_mlocked) 626 #else 627 #define __PG_MLOCKED 0 628 #endif 629 630 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 631 #define __PG_COMPOUND_LOCK (1 << PG_compound_lock) 632 #else 633 #define __PG_COMPOUND_LOCK 0 634 #endif 635 636 /* 637 * Flags checked when a page is freed. Pages being freed should not have 638 * these flags set. It they are, there is a problem. 639 */ 640 #define PAGE_FLAGS_CHECK_AT_FREE \ 641 (1 << PG_lru | 1 << PG_locked | \ 642 1 << PG_private | 1 << PG_private_2 | \ 643 1 << PG_writeback | 1 << PG_reserved | \ 644 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \ 645 1 << PG_unevictable | __PG_MLOCKED | \ 646 __PG_COMPOUND_LOCK) 647 648 /* 649 * Flags checked when a page is prepped for return by the page allocator. 650 * Pages being prepped should not have these flags set. It they are set, 651 * there has been a kernel bug or struct page corruption. 652 * 653 * __PG_HWPOISON is exceptional because it needs to be kept beyond page's 654 * alloc-free cycle to prevent from reusing the page. 655 */ 656 #define PAGE_FLAGS_CHECK_AT_PREP \ 657 (((1 << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON) 658 659 #define PAGE_FLAGS_PRIVATE \ 660 (1 << PG_private | 1 << PG_private_2) 661 /** 662 * page_has_private - Determine if page has private stuff 663 * @page: The page to be checked 664 * 665 * Determine if a page has private stuff, indicating that release routines 666 * should be invoked upon it. 667 */ 668 static inline int page_has_private(struct page *page) 669 { 670 return !!(page->flags & PAGE_FLAGS_PRIVATE); 671 } 672 673 #endif /* !__GENERATING_BOUNDS_H */ 674 675 #endif /* PAGE_FLAGS_H */ 676