2 * Macros for manipulating and testing page->flags
8 #include <linux/types.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 */
17 * Various page->flags bits:
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)...
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.
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.
30 * PG_locked also pins a page in pagecache, and blocks truncation of the file
33 * page_waitqueue(page) is a wait queue of all tasks waiting for the page
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.
39 * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
40 * file-backed pagecache (see mm/vmscan.c).
42 * PG_error is set to indicate that an I/O error occurred on this page.
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
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
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!
59 * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
60 * locked- and dirty-page accounting.
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.
66 * | FIELD | ... | FLAGS |
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).
75 PG_locked, /* Page is locked. Don't touch. */
82 PG_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
84 PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
87 PG_private, /* If pagecache, has fs-private data */
88 PG_private_2, /* If pagecache, has fs aux data */
89 PG_writeback, /* Page is under writeback */
90 PG_head, /* A head page */
91 PG_mappedtodisk, /* Has blocks allocated on-disk */
92 PG_reclaim, /* To be reclaimed asap */
93 PG_swapbacked, /* Page is backed by RAM/swap */
94 PG_unevictable, /* Page is "unevictable" */
96 PG_mlocked, /* Page is vma mlocked */
98 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
99 PG_uncached, /* Page has been mapped as uncached */
101 #ifdef CONFIG_MEMORY_FAILURE
102 PG_hwpoison, /* hardware poisoned page. Don't touch */
104 #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
111 PG_checked = PG_owner_priv_1,
114 PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */
116 /* Two page bits are conscripted by FS-Cache to maintain local caching
117 * state. These bits are set on pages belonging to the netfs's inodes
118 * when those inodes are being locally cached.
120 PG_fscache = PG_private_2, /* page backed by cache */
123 /* Pinned in Xen as a read-only pagetable page. */
124 PG_pinned = PG_owner_priv_1,
125 /* Pinned as part of domain save (see xen_mm_pin_all()). */
126 PG_savepinned = PG_dirty,
127 /* Has a grant mapping of another (foreign) domain's page. */
128 PG_foreign = PG_owner_priv_1,
131 PG_slob_free = PG_private,
133 /* Compound pages. Stored in first tail page's flags */
134 PG_double_map = PG_private_2,
136 /* non-lru isolated movable page */
137 PG_isolated = PG_reclaim,
140 #ifndef __GENERATING_BOUNDS_H
142 struct page; /* forward declaration */
144 static inline struct page *compound_head(struct page *page)
146 unsigned long head = READ_ONCE(page->compound_head);
148 if (unlikely(head & 1))
149 return (struct page *) (head - 1);
153 static __always_inline int PageTail(struct page *page)
155 return READ_ONCE(page->compound_head) & 1;
158 static __always_inline int PageCompound(struct page *page)
160 return test_bit(PG_head, &page->flags) || PageTail(page);
164 * Page flags policies wrt compound pages
167 * the page flag is relevant for small, head and tail pages.
170 * for compound page all operations related to the page flag applied to
174 * for compound page, callers only ever operate on the head page.
177 * modifications of the page flag must be done on small or head pages,
178 * checks can be done on tail pages too.
181 * the page flag is not relevant for compound pages.
183 #define PF_ANY(page, enforce) page
184 #define PF_HEAD(page, enforce) compound_head(page)
185 #define PF_ONLY_HEAD(page, enforce) ({ \
186 VM_BUG_ON_PGFLAGS(PageTail(page), page); \
188 #define PF_NO_TAIL(page, enforce) ({ \
189 VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
190 compound_head(page);})
191 #define PF_NO_COMPOUND(page, enforce) ({ \
192 VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
196 * Macros to create function definitions for page flags
198 #define TESTPAGEFLAG(uname, lname, policy) \
199 static __always_inline int Page##uname(struct page *page) \
200 { return test_bit(PG_##lname, &policy(page, 0)->flags); }
202 #define SETPAGEFLAG(uname, lname, policy) \
203 static __always_inline void SetPage##uname(struct page *page) \
204 { set_bit(PG_##lname, &policy(page, 1)->flags); }
206 #define CLEARPAGEFLAG(uname, lname, policy) \
207 static __always_inline void ClearPage##uname(struct page *page) \
208 { clear_bit(PG_##lname, &policy(page, 1)->flags); }
210 #define __SETPAGEFLAG(uname, lname, policy) \
211 static __always_inline void __SetPage##uname(struct page *page) \
212 { __set_bit(PG_##lname, &policy(page, 1)->flags); }
214 #define __CLEARPAGEFLAG(uname, lname, policy) \
215 static __always_inline void __ClearPage##uname(struct page *page) \
216 { __clear_bit(PG_##lname, &policy(page, 1)->flags); }
218 #define TESTSETFLAG(uname, lname, policy) \
219 static __always_inline int TestSetPage##uname(struct page *page) \
220 { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
222 #define TESTCLEARFLAG(uname, lname, policy) \
223 static __always_inline int TestClearPage##uname(struct page *page) \
224 { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
226 #define PAGEFLAG(uname, lname, policy) \
227 TESTPAGEFLAG(uname, lname, policy) \
228 SETPAGEFLAG(uname, lname, policy) \
229 CLEARPAGEFLAG(uname, lname, policy)
231 #define __PAGEFLAG(uname, lname, policy) \
232 TESTPAGEFLAG(uname, lname, policy) \
233 __SETPAGEFLAG(uname, lname, policy) \
234 __CLEARPAGEFLAG(uname, lname, policy)
236 #define TESTSCFLAG(uname, lname, policy) \
237 TESTSETFLAG(uname, lname, policy) \
238 TESTCLEARFLAG(uname, lname, policy)
240 #define TESTPAGEFLAG_FALSE(uname) \
241 static inline int Page##uname(const struct page *page) { return 0; }
243 #define SETPAGEFLAG_NOOP(uname) \
244 static inline void SetPage##uname(struct page *page) { }
246 #define CLEARPAGEFLAG_NOOP(uname) \
247 static inline void ClearPage##uname(struct page *page) { }
249 #define __CLEARPAGEFLAG_NOOP(uname) \
250 static inline void __ClearPage##uname(struct page *page) { }
252 #define TESTSETFLAG_FALSE(uname) \
253 static inline int TestSetPage##uname(struct page *page) { return 0; }
255 #define TESTCLEARFLAG_FALSE(uname) \
256 static inline int TestClearPage##uname(struct page *page) { return 0; }
258 #define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \
259 SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname)
261 #define TESTSCFLAG_FALSE(uname) \
262 TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
264 __PAGEFLAG(Locked, locked, PF_NO_TAIL)
265 PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) __CLEARPAGEFLAG(Waiters, waiters, PF_ONLY_HEAD)
266 PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND)
267 PAGEFLAG(Referenced, referenced, PF_HEAD)
268 TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
269 __SETPAGEFLAG(Referenced, referenced, PF_HEAD)
270 PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
271 __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
272 PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
273 PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
274 TESTCLEARFLAG(Active, active, PF_HEAD)
275 __PAGEFLAG(Slab, slab, PF_NO_TAIL)
276 __PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
277 PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */
280 PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
281 TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)
282 PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
283 PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
285 PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
286 __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
287 PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
288 __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
289 __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
292 * Private page markings that may be used by the filesystem that owns the page
293 * for its own purposes.
294 * - PG_private and PG_private_2 cause releasepage() and co to be invoked
296 PAGEFLAG(Private, private, PF_ANY) __SETPAGEFLAG(Private, private, PF_ANY)
297 __CLEARPAGEFLAG(Private, private, PF_ANY)
298 PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY)
299 PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
300 TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
303 * Only test-and-set exist for PG_writeback. The unconditional operators are
304 * risky: they bypass page accounting.
306 TESTPAGEFLAG(Writeback, writeback, PF_NO_COMPOUND)
307 TESTSCFLAG(Writeback, writeback, PF_NO_COMPOUND)
308 PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL)
310 /* PG_readahead is only used for reads; PG_reclaim is only for writes */
311 PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL)
312 TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL)
313 PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND)
314 TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND)
316 #ifdef CONFIG_HIGHMEM
318 * Must use a macro here due to header dependency issues. page_zone() is not
319 * available at this point.
321 #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
323 PAGEFLAG_FALSE(HighMem)
327 static __always_inline int PageSwapCache(struct page *page)
329 #ifdef CONFIG_THP_SWAP
330 page = compound_head(page);
332 return PageSwapBacked(page) && test_bit(PG_swapcache, &page->flags);
335 SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
336 CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
338 PAGEFLAG_FALSE(SwapCache)
341 PAGEFLAG(Unevictable, unevictable, PF_HEAD)
342 __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD)
343 TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD)
346 PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
347 __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
348 TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL)
350 PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked)
351 TESTSCFLAG_FALSE(Mlocked)
354 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
355 PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND)
357 PAGEFLAG_FALSE(Uncached)
360 #ifdef CONFIG_MEMORY_FAILURE
361 PAGEFLAG(HWPoison, hwpoison, PF_ANY)
362 TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
363 #define __PG_HWPOISON (1UL << PG_hwpoison)
365 PAGEFLAG_FALSE(HWPoison)
366 #define __PG_HWPOISON 0
369 #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
370 TESTPAGEFLAG(Young, young, PF_ANY)
371 SETPAGEFLAG(Young, young, PF_ANY)
372 TESTCLEARFLAG(Young, young, PF_ANY)
373 PAGEFLAG(Idle, idle, PF_ANY)
377 * On an anonymous page mapped into a user virtual memory area,
378 * page->mapping points to its anon_vma, not to a struct address_space;
379 * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h.
381 * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
382 * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON
383 * bit; and then page->mapping points, not to an anon_vma, but to a private
384 * structure which KSM associates with that merged page. See ksm.h.
386 * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable
387 * page and then page->mapping points a struct address_space.
389 * Please note that, confusingly, "page_mapping" refers to the inode
390 * address_space which maps the page from disk; whereas "page_mapped"
391 * refers to user virtual address space into which the page is mapped.
393 #define PAGE_MAPPING_ANON 0x1
394 #define PAGE_MAPPING_MOVABLE 0x2
395 #define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
396 #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
398 static __always_inline int PageMappingFlags(struct page *page)
400 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0;
403 static __always_inline int PageAnon(struct page *page)
405 page = compound_head(page);
406 return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
409 static __always_inline int __PageMovable(struct page *page)
411 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
412 PAGE_MAPPING_MOVABLE;
417 * A KSM page is one of those write-protected "shared pages" or "merged pages"
418 * which KSM maps into multiple mms, wherever identical anonymous page content
419 * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any
420 * anon_vma, but to that page's node of the stable tree.
422 static __always_inline int PageKsm(struct page *page)
424 page = compound_head(page);
425 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
429 TESTPAGEFLAG_FALSE(Ksm)
432 u64 stable_page_flags(struct page *page);
434 static inline int PageUptodate(struct page *page)
437 page = compound_head(page);
438 ret = test_bit(PG_uptodate, &(page)->flags);
440 * Must ensure that the data we read out of the page is loaded
441 * _after_ we've loaded page->flags to check for PageUptodate.
442 * We can skip the barrier if the page is not uptodate, because
443 * we wouldn't be reading anything from it.
445 * See SetPageUptodate() for the other side of the story.
453 static __always_inline void __SetPageUptodate(struct page *page)
455 VM_BUG_ON_PAGE(PageTail(page), page);
457 __set_bit(PG_uptodate, &page->flags);
460 static __always_inline void SetPageUptodate(struct page *page)
462 VM_BUG_ON_PAGE(PageTail(page), page);
464 * Memory barrier must be issued before setting the PG_uptodate bit,
465 * so that all previous stores issued in order to bring the page
466 * uptodate are actually visible before PageUptodate becomes true.
469 set_bit(PG_uptodate, &page->flags);
472 CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)
474 int test_clear_page_writeback(struct page *page);
475 int __test_set_page_writeback(struct page *page, bool keep_write);
477 #define test_set_page_writeback(page) \
478 __test_set_page_writeback(page, false)
479 #define test_set_page_writeback_keepwrite(page) \
480 __test_set_page_writeback(page, true)
482 static inline void set_page_writeback(struct page *page)
484 test_set_page_writeback(page);
487 static inline void set_page_writeback_keepwrite(struct page *page)
489 test_set_page_writeback_keepwrite(page);
492 __PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY)
494 static __always_inline void set_compound_head(struct page *page, struct page *head)
496 WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
499 static __always_inline void clear_compound_head(struct page *page)
501 WRITE_ONCE(page->compound_head, 0);
504 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
505 static inline void ClearPageCompound(struct page *page)
507 BUG_ON(!PageHead(page));
512 #define PG_head_mask ((1UL << PG_head))
514 #ifdef CONFIG_HUGETLB_PAGE
515 int PageHuge(struct page *page);
516 int PageHeadHuge(struct page *page);
517 bool page_huge_active(struct page *page);
519 TESTPAGEFLAG_FALSE(Huge)
520 TESTPAGEFLAG_FALSE(HeadHuge)
522 static inline bool page_huge_active(struct page *page)
529 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
531 * PageHuge() only returns true for hugetlbfs pages, but not for
532 * normal or transparent huge pages.
534 * PageTransHuge() returns true for both transparent huge and
535 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
536 * called only in the core VM paths where hugetlbfs pages can't exist.
538 static inline int PageTransHuge(struct page *page)
540 VM_BUG_ON_PAGE(PageTail(page), page);
541 return PageHead(page);
545 * PageTransCompound returns true for both transparent huge pages
546 * and hugetlbfs pages, so it should only be called when it's known
547 * that hugetlbfs pages aren't involved.
549 static inline int PageTransCompound(struct page *page)
551 return PageCompound(page);
555 * PageTransCompoundMap is the same as PageTransCompound, but it also
556 * guarantees the primary MMU has the entire compound page mapped
557 * through pmd_trans_huge, which in turn guarantees the secondary MMUs
558 * can also map the entire compound page. This allows the secondary
559 * MMUs to call get_user_pages() only once for each compound page and
560 * to immediately map the entire compound page with a single secondary
561 * MMU fault. If there will be a pmd split later, the secondary MMUs
562 * will get an update through the MMU notifier invalidation through
565 * Unlike PageTransCompound, this is safe to be called only while
566 * split_huge_pmd() cannot run from under us, like if protected by the
567 * MMU notifier, otherwise it may result in page->_mapcount < 0 false
570 static inline int PageTransCompoundMap(struct page *page)
572 return PageTransCompound(page) && atomic_read(&page->_mapcount) < 0;
576 * PageTransTail returns true for both transparent huge pages
577 * and hugetlbfs pages, so it should only be called when it's known
578 * that hugetlbfs pages aren't involved.
580 static inline int PageTransTail(struct page *page)
582 return PageTail(page);
586 * PageDoubleMap indicates that the compound page is mapped with PTEs as well
589 * This is required for optimization of rmap operations for THP: we can postpone
590 * per small page mapcount accounting (and its overhead from atomic operations)
591 * until the first PMD split.
593 * For the page PageDoubleMap means ->_mapcount in all sub-pages is offset up
594 * by one. This reference will go away with last compound_mapcount.
596 * See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap().
598 static inline int PageDoubleMap(struct page *page)
600 return PageHead(page) && test_bit(PG_double_map, &page[1].flags);
603 static inline void SetPageDoubleMap(struct page *page)
605 VM_BUG_ON_PAGE(!PageHead(page), page);
606 set_bit(PG_double_map, &page[1].flags);
609 static inline void ClearPageDoubleMap(struct page *page)
611 VM_BUG_ON_PAGE(!PageHead(page), page);
612 clear_bit(PG_double_map, &page[1].flags);
614 static inline int TestSetPageDoubleMap(struct page *page)
616 VM_BUG_ON_PAGE(!PageHead(page), page);
617 return test_and_set_bit(PG_double_map, &page[1].flags);
620 static inline int TestClearPageDoubleMap(struct page *page)
622 VM_BUG_ON_PAGE(!PageHead(page), page);
623 return test_and_clear_bit(PG_double_map, &page[1].flags);
627 TESTPAGEFLAG_FALSE(TransHuge)
628 TESTPAGEFLAG_FALSE(TransCompound)
629 TESTPAGEFLAG_FALSE(TransCompoundMap)
630 TESTPAGEFLAG_FALSE(TransTail)
631 PAGEFLAG_FALSE(DoubleMap)
632 TESTSETFLAG_FALSE(DoubleMap)
633 TESTCLEARFLAG_FALSE(DoubleMap)
637 * For pages that are never mapped to userspace, page->mapcount may be
638 * used for storing extra information about page type. Any value used
639 * for this purpose must be <= -2, but it's better start not too close
640 * to -2 so that an underflow of the page_mapcount() won't be mistaken
641 * for a special page.
643 #define PAGE_MAPCOUNT_OPS(uname, lname) \
644 static __always_inline int Page##uname(struct page *page) \
646 return atomic_read(&page->_mapcount) == \
647 PAGE_##lname##_MAPCOUNT_VALUE; \
649 static __always_inline void __SetPage##uname(struct page *page) \
651 VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page); \
652 atomic_set(&page->_mapcount, PAGE_##lname##_MAPCOUNT_VALUE); \
654 static __always_inline void __ClearPage##uname(struct page *page) \
656 VM_BUG_ON_PAGE(!Page##uname(page), page); \
657 atomic_set(&page->_mapcount, -1); \
661 * PageBuddy() indicate that the page is free and in the buddy system
662 * (see mm/page_alloc.c).
664 #define PAGE_BUDDY_MAPCOUNT_VALUE (-128)
665 PAGE_MAPCOUNT_OPS(Buddy, BUDDY)
668 * PageBalloon() is set on pages that are on the balloon page list
669 * (see mm/balloon_compaction.c).
671 #define PAGE_BALLOON_MAPCOUNT_VALUE (-256)
672 PAGE_MAPCOUNT_OPS(Balloon, BALLOON)
675 * If kmemcg is enabled, the buddy allocator will set PageKmemcg() on
676 * pages allocated with __GFP_ACCOUNT. It gets cleared on page free.
678 #define PAGE_KMEMCG_MAPCOUNT_VALUE (-512)
679 PAGE_MAPCOUNT_OPS(Kmemcg, KMEMCG)
681 extern bool is_free_buddy_page(struct page *page);
683 __PAGEFLAG(Isolated, isolated, PF_ANY);
686 * If network-based swap is enabled, sl*b must keep track of whether pages
687 * were allocated from pfmemalloc reserves.
689 static inline int PageSlabPfmemalloc(struct page *page)
691 VM_BUG_ON_PAGE(!PageSlab(page), page);
692 return PageActive(page);
695 static inline void SetPageSlabPfmemalloc(struct page *page)
697 VM_BUG_ON_PAGE(!PageSlab(page), page);
701 static inline void __ClearPageSlabPfmemalloc(struct page *page)
703 VM_BUG_ON_PAGE(!PageSlab(page), page);
704 __ClearPageActive(page);
707 static inline void ClearPageSlabPfmemalloc(struct page *page)
709 VM_BUG_ON_PAGE(!PageSlab(page), page);
710 ClearPageActive(page);
714 #define __PG_MLOCKED (1UL << PG_mlocked)
716 #define __PG_MLOCKED 0
720 * Flags checked when a page is freed. Pages being freed should not have
721 * these flags set. It they are, there is a problem.
723 #define PAGE_FLAGS_CHECK_AT_FREE \
724 (1UL << PG_lru | 1UL << PG_locked | \
725 1UL << PG_private | 1UL << PG_private_2 | \
726 1UL << PG_writeback | 1UL << PG_reserved | \
727 1UL << PG_slab | 1UL << PG_active | \
728 1UL << PG_unevictable | __PG_MLOCKED)
731 * Flags checked when a page is prepped for return by the page allocator.
732 * Pages being prepped should not have these flags set. It they are set,
733 * there has been a kernel bug or struct page corruption.
735 * __PG_HWPOISON is exceptional because it needs to be kept beyond page's
736 * alloc-free cycle to prevent from reusing the page.
738 #define PAGE_FLAGS_CHECK_AT_PREP \
739 (((1UL << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON)
741 #define PAGE_FLAGS_PRIVATE \
742 (1UL << PG_private | 1UL << PG_private_2)
744 * page_has_private - Determine if page has private stuff
745 * @page: The page to be checked
747 * Determine if a page has private stuff, indicating that release routines
748 * should be invoked upon it.
750 static inline int page_has_private(struct page *page)
752 return !!(page->flags & PAGE_FLAGS_PRIVATE);
759 #undef PF_NO_COMPOUND
760 #endif /* !__GENERATING_BOUNDS_H */
762 #endif /* PAGE_FLAGS_H */