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 */
page_fixed_fake_head(const struct page * page)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
page_fixed_fake_head(const struct page * page)233 static inline const struct page *page_fixed_fake_head(const struct page *page)
234 {
235 return page;
236 }
237 #endif
238
page_is_fake_head(struct page * page)239 static __always_inline int page_is_fake_head(struct page *page)
240 {
241 return page_fixed_fake_head(page) != page;
242 }
243
_compound_head(const struct page * page)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
PageTail(struct page * page)283 static __always_inline int PageTail(struct page *page)
284 {
285 return READ_ONCE(page->compound_head) & 1 || page_is_fake_head(page);
286 }
287
PageCompound(struct page * page)288 static __always_inline int PageCompound(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
PagePoisoned(const struct page * page)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
page_init_poison(struct page * page,size_t size)303 static inline void page_init_poison(struct page *page, size_t size)
304 {
305 }
306 #endif
307
folio_flags(struct folio * folio,unsigned n)308 static unsigned long *folio_flags(struct folio *folio, unsigned n)
309 {
310 struct page *page = &folio->page;
311
312 VM_BUG_ON_PGFLAGS(PageTail(page), page);
313 VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page);
314 return &page[n].flags;
315 }
316
317 /*
318 * Page flags policies wrt compound pages
319 *
320 * PF_POISONED_CHECK
321 * check if this struct page poisoned/uninitialized
322 *
323 * PF_ANY:
324 * the page flag is relevant for small, head and tail pages.
325 *
326 * PF_HEAD:
327 * for compound page all operations related to the page flag applied to
328 * head page.
329 *
330 * PF_ONLY_HEAD:
331 * for compound page, callers only ever operate on the head page.
332 *
333 * PF_NO_TAIL:
334 * modifications of the page flag must be done on small or head pages,
335 * checks can be done on tail pages too.
336 *
337 * PF_NO_COMPOUND:
338 * the page flag is not relevant for compound pages.
339 *
340 * PF_SECOND:
341 * the page flag is stored in the first tail page.
342 */
343 #define PF_POISONED_CHECK(page) ({ \
344 VM_BUG_ON_PGFLAGS(PagePoisoned(page), page); \
345 page; })
346 #define PF_ANY(page, enforce) PF_POISONED_CHECK(page)
347 #define PF_HEAD(page, enforce) PF_POISONED_CHECK(compound_head(page))
348 #define PF_ONLY_HEAD(page, enforce) ({ \
349 VM_BUG_ON_PGFLAGS(PageTail(page), page); \
350 PF_POISONED_CHECK(page); })
351 #define PF_NO_TAIL(page, enforce) ({ \
352 VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
353 PF_POISONED_CHECK(compound_head(page)); })
354 #define PF_NO_COMPOUND(page, enforce) ({ \
355 VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
356 PF_POISONED_CHECK(page); })
357 #define PF_SECOND(page, enforce) ({ \
358 VM_BUG_ON_PGFLAGS(!PageHead(page), page); \
359 PF_POISONED_CHECK(&page[1]); })
360
361 /* Which page is the flag stored in */
362 #define FOLIO_PF_ANY 0
363 #define FOLIO_PF_HEAD 0
364 #define FOLIO_PF_ONLY_HEAD 0
365 #define FOLIO_PF_NO_TAIL 0
366 #define FOLIO_PF_NO_COMPOUND 0
367 #define FOLIO_PF_SECOND 1
368
369 /*
370 * Macros to create function definitions for page flags
371 */
372 #define TESTPAGEFLAG(uname, lname, policy) \
373 static __always_inline bool folio_test_##lname(struct folio *folio) \
374 { return test_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
375 static __always_inline int Page##uname(struct page *page) \
376 { return test_bit(PG_##lname, &policy(page, 0)->flags); }
377
378 #define SETPAGEFLAG(uname, lname, policy) \
379 static __always_inline \
380 void folio_set_##lname(struct folio *folio) \
381 { set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
382 static __always_inline void SetPage##uname(struct page *page) \
383 { set_bit(PG_##lname, &policy(page, 1)->flags); }
384
385 #define CLEARPAGEFLAG(uname, lname, policy) \
386 static __always_inline \
387 void folio_clear_##lname(struct folio *folio) \
388 { clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
389 static __always_inline void ClearPage##uname(struct page *page) \
390 { clear_bit(PG_##lname, &policy(page, 1)->flags); }
391
392 #define __SETPAGEFLAG(uname, lname, policy) \
393 static __always_inline \
394 void __folio_set_##lname(struct folio *folio) \
395 { __set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
396 static __always_inline void __SetPage##uname(struct page *page) \
397 { __set_bit(PG_##lname, &policy(page, 1)->flags); }
398
399 #define __CLEARPAGEFLAG(uname, lname, policy) \
400 static __always_inline \
401 void __folio_clear_##lname(struct folio *folio) \
402 { __clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
403 static __always_inline void __ClearPage##uname(struct page *page) \
404 { __clear_bit(PG_##lname, &policy(page, 1)->flags); }
405
406 #define TESTSETFLAG(uname, lname, policy) \
407 static __always_inline \
408 bool folio_test_set_##lname(struct folio *folio) \
409 { return test_and_set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
410 static __always_inline int TestSetPage##uname(struct page *page) \
411 { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
412
413 #define TESTCLEARFLAG(uname, lname, policy) \
414 static __always_inline \
415 bool folio_test_clear_##lname(struct folio *folio) \
416 { return test_and_clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
417 static __always_inline int TestClearPage##uname(struct page *page) \
418 { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
419
420 #define PAGEFLAG(uname, lname, policy) \
421 TESTPAGEFLAG(uname, lname, policy) \
422 SETPAGEFLAG(uname, lname, policy) \
423 CLEARPAGEFLAG(uname, lname, policy)
424
425 #define __PAGEFLAG(uname, lname, policy) \
426 TESTPAGEFLAG(uname, lname, policy) \
427 __SETPAGEFLAG(uname, lname, policy) \
428 __CLEARPAGEFLAG(uname, lname, policy)
429
430 #define TESTSCFLAG(uname, lname, policy) \
431 TESTSETFLAG(uname, lname, policy) \
432 TESTCLEARFLAG(uname, lname, policy)
433
434 #define FOLIO_TEST_FLAG_FALSE(name) \
435 static inline bool folio_test_##name(const struct folio *folio) \
436 { return false; }
437 #define FOLIO_SET_FLAG_NOOP(name) \
438 static inline void folio_set_##name(struct folio *folio) { }
439 #define FOLIO_CLEAR_FLAG_NOOP(name) \
440 static inline void folio_clear_##name(struct folio *folio) { }
441 #define __FOLIO_SET_FLAG_NOOP(name) \
442 static inline void __folio_set_##name(struct folio *folio) { }
443 #define __FOLIO_CLEAR_FLAG_NOOP(name) \
444 static inline void __folio_clear_##name(struct folio *folio) { }
445 #define FOLIO_TEST_SET_FLAG_FALSE(name) \
446 static inline bool folio_test_set_##name(struct folio *folio) \
447 { return false; }
448 #define FOLIO_TEST_CLEAR_FLAG_FALSE(name) \
449 static inline bool folio_test_clear_##name(struct folio *folio) \
450 { return false; }
451
452 #define FOLIO_FLAG_FALSE(name) \
453 FOLIO_TEST_FLAG_FALSE(name) \
454 FOLIO_SET_FLAG_NOOP(name) \
455 FOLIO_CLEAR_FLAG_NOOP(name)
456
457 #define TESTPAGEFLAG_FALSE(uname, lname) \
458 FOLIO_TEST_FLAG_FALSE(lname) \
459 static inline int Page##uname(const struct page *page) { return 0; }
460
461 #define SETPAGEFLAG_NOOP(uname, lname) \
462 FOLIO_SET_FLAG_NOOP(lname) \
463 static inline void SetPage##uname(struct page *page) { }
464
465 #define CLEARPAGEFLAG_NOOP(uname, lname) \
466 FOLIO_CLEAR_FLAG_NOOP(lname) \
467 static inline void ClearPage##uname(struct page *page) { }
468
469 #define __CLEARPAGEFLAG_NOOP(uname, lname) \
470 __FOLIO_CLEAR_FLAG_NOOP(lname) \
471 static inline void __ClearPage##uname(struct page *page) { }
472
473 #define TESTSETFLAG_FALSE(uname, lname) \
474 FOLIO_TEST_SET_FLAG_FALSE(lname) \
475 static inline int TestSetPage##uname(struct page *page) { return 0; }
476
477 #define TESTCLEARFLAG_FALSE(uname, lname) \
478 FOLIO_TEST_CLEAR_FLAG_FALSE(lname) \
479 static inline int TestClearPage##uname(struct page *page) { return 0; }
480
481 #define PAGEFLAG_FALSE(uname, lname) TESTPAGEFLAG_FALSE(uname, lname) \
482 SETPAGEFLAG_NOOP(uname, lname) CLEARPAGEFLAG_NOOP(uname, lname)
483
484 #define TESTSCFLAG_FALSE(uname, lname) \
485 TESTSETFLAG_FALSE(uname, lname) TESTCLEARFLAG_FALSE(uname, lname)
486
487 __PAGEFLAG(Locked, locked, PF_NO_TAIL)
488 PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD)
489 PAGEFLAG(Error, error, PF_NO_TAIL) TESTCLEARFLAG(Error, error, PF_NO_TAIL)
490 PAGEFLAG(Referenced, referenced, PF_HEAD)
491 TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
492 __SETPAGEFLAG(Referenced, referenced, PF_HEAD)
493 PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
494 __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
495 PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
496 TESTCLEARFLAG(LRU, lru, PF_HEAD)
497 PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
498 TESTCLEARFLAG(Active, active, PF_HEAD)
499 PAGEFLAG(Workingset, workingset, PF_HEAD)
500 TESTCLEARFLAG(Workingset, workingset, PF_HEAD)
501 __PAGEFLAG(Slab, slab, PF_NO_TAIL)
502 PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */
503
504 /* Xen */
505 PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
506 TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)
507 PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
508 PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
PAGEFLAG(XenRemapped,xen_remapped,PF_NO_COMPOUND)509 PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
510 TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
511
512 PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
513 __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
514 __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
515 PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
516 __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
517 __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
518
519 /*
520 * Private page markings that may be used by the filesystem that owns the page
521 * for its own purposes.
522 * - PG_private and PG_private_2 cause release_folio() and co to be invoked
523 */
524 PAGEFLAG(Private, private, PF_ANY)
525 PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY)
526 PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
527 TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
528
529 /*
530 * Only test-and-set exist for PG_writeback. The unconditional operators are
531 * risky: they bypass page accounting.
532 */
533 TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL)
534 TESTSCFLAG(Writeback, writeback, PF_NO_TAIL)
535 PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL)
536
537 /* PG_readahead is only used for reads; PG_reclaim is only for writes */
538 PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL)
539 TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL)
540 PAGEFLAG(Readahead, readahead, PF_NO_COMPOUND)
541 TESTCLEARFLAG(Readahead, readahead, PF_NO_COMPOUND)
542
543 #ifdef CONFIG_HIGHMEM
544 /*
545 * Must use a macro here due to header dependency issues. page_zone() is not
546 * available at this point.
547 */
548 #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
549 #define folio_test_highmem(__f) is_highmem_idx(folio_zonenum(__f))
550 #else
551 PAGEFLAG_FALSE(HighMem, highmem)
552 #endif
553
554 #ifdef CONFIG_SWAP
555 static __always_inline bool folio_test_swapcache(struct folio *folio)
556 {
557 return folio_test_swapbacked(folio) &&
558 test_bit(PG_swapcache, folio_flags(folio, 0));
559 }
560
PageSwapCache(struct page * page)561 static __always_inline bool PageSwapCache(struct page *page)
562 {
563 return folio_test_swapcache(page_folio(page));
564 }
565
566 SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
567 CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
568 #else
569 PAGEFLAG_FALSE(SwapCache, swapcache)
570 #endif
571
572 PAGEFLAG(Unevictable, unevictable, PF_HEAD)
573 __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD)
574 TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD)
575
576 #ifdef CONFIG_MMU
577 PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
578 __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
579 TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL)
580 #else
581 PAGEFLAG_FALSE(Mlocked, mlocked) __CLEARPAGEFLAG_NOOP(Mlocked, mlocked)
582 TESTSCFLAG_FALSE(Mlocked, mlocked)
583 #endif
584
585 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
586 PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND)
587 #else
588 PAGEFLAG_FALSE(Uncached, uncached)
589 #endif
590
591 #ifdef CONFIG_MEMORY_FAILURE
592 PAGEFLAG(HWPoison, hwpoison, PF_ANY)
593 TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
594 #define __PG_HWPOISON (1UL << PG_hwpoison)
595 #define MAGIC_HWPOISON 0x48575053U /* HWPS */
596 extern void SetPageHWPoisonTakenOff(struct page *page);
597 extern void ClearPageHWPoisonTakenOff(struct page *page);
598 extern bool take_page_off_buddy(struct page *page);
599 extern bool put_page_back_buddy(struct page *page);
600 #else
601 PAGEFLAG_FALSE(HWPoison, hwpoison)
602 #define __PG_HWPOISON 0
603 #endif
604
605 #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT)
TESTPAGEFLAG(Young,young,PF_ANY)606 TESTPAGEFLAG(Young, young, PF_ANY)
607 SETPAGEFLAG(Young, young, PF_ANY)
608 TESTCLEARFLAG(Young, young, PF_ANY)
609 PAGEFLAG(Idle, idle, PF_ANY)
610 #endif
611
612 /*
613 * PageReported() is used to track reported free pages within the Buddy
614 * allocator. We can use the non-atomic version of the test and set
615 * operations as both should be shielded with the zone lock to prevent
616 * any possible races on the setting or clearing of the bit.
617 */
618 __PAGEFLAG(Reported, reported, PF_NO_COMPOUND)
619
620 #ifdef CONFIG_MEMORY_HOTPLUG
621 PAGEFLAG(VmemmapSelfHosted, vmemmap_self_hosted, PF_ANY)
622 #else
623 PAGEFLAG_FALSE(VmemmapSelfHosted, vmemmap_self_hosted)
624 #endif
625
626 /*
627 * On an anonymous page mapped into a user virtual memory area,
628 * page->mapping points to its anon_vma, not to a struct address_space;
629 * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h.
630 *
631 * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
632 * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON
633 * bit; and then page->mapping points, not to an anon_vma, but to a private
634 * structure which KSM associates with that merged page. See ksm.h.
635 *
636 * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable
637 * page and then page->mapping points to a struct movable_operations.
638 *
639 * Please note that, confusingly, "page_mapping" refers to the inode
640 * address_space which maps the page from disk; whereas "page_mapped"
641 * refers to user virtual address space into which the page is mapped.
642 *
643 * For slab pages, since slab reuses the bits in struct page to store its
644 * internal states, the page->mapping does not exist as such, nor do these
645 * flags below. So in order to avoid testing non-existent bits, please
646 * make sure that PageSlab(page) actually evaluates to false before calling
647 * the following functions (e.g., PageAnon). See mm/slab.h.
648 */
649 #define PAGE_MAPPING_ANON 0x1
650 #define PAGE_MAPPING_MOVABLE 0x2
651 #define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
652 #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
653
654 /*
655 * Different with flags above, this flag is used only for fsdax mode. It
656 * indicates that this page->mapping is now under reflink case.
657 */
658 #define PAGE_MAPPING_DAX_SHARED ((void *)0x1)
659
660 static __always_inline bool folio_mapping_flags(struct folio *folio)
661 {
662 return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) != 0;
663 }
664
PageMappingFlags(struct page * page)665 static __always_inline int PageMappingFlags(struct page *page)
666 {
667 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0;
668 }
669
folio_test_anon(struct folio * folio)670 static __always_inline bool folio_test_anon(struct folio *folio)
671 {
672 return ((unsigned long)folio->mapping & PAGE_MAPPING_ANON) != 0;
673 }
674
PageAnon(struct page * page)675 static __always_inline bool PageAnon(struct page *page)
676 {
677 return folio_test_anon(page_folio(page));
678 }
679
__folio_test_movable(const struct folio * folio)680 static __always_inline bool __folio_test_movable(const struct folio *folio)
681 {
682 return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) ==
683 PAGE_MAPPING_MOVABLE;
684 }
685
__PageMovable(struct page * page)686 static __always_inline int __PageMovable(struct page *page)
687 {
688 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
689 PAGE_MAPPING_MOVABLE;
690 }
691
692 #ifdef CONFIG_KSM
693 /*
694 * A KSM page is one of those write-protected "shared pages" or "merged pages"
695 * which KSM maps into multiple mms, wherever identical anonymous page content
696 * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any
697 * anon_vma, but to that page's node of the stable tree.
698 */
folio_test_ksm(struct folio * folio)699 static __always_inline bool folio_test_ksm(struct folio *folio)
700 {
701 return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) ==
702 PAGE_MAPPING_KSM;
703 }
704
PageKsm(struct page * page)705 static __always_inline bool PageKsm(struct page *page)
706 {
707 return folio_test_ksm(page_folio(page));
708 }
709 #else
710 TESTPAGEFLAG_FALSE(Ksm, ksm)
711 #endif
712
713 u64 stable_page_flags(struct page *page);
714
715 /**
716 * folio_test_uptodate - Is this folio up to date?
717 * @folio: The folio.
718 *
719 * The uptodate flag is set on a folio when every byte in the folio is
720 * at least as new as the corresponding bytes on storage. Anonymous
721 * and CoW folios are always uptodate. If the folio is not uptodate,
722 * some of the bytes in it may be; see the is_partially_uptodate()
723 * address_space operation.
724 */
folio_test_uptodate(struct folio * folio)725 static inline bool folio_test_uptodate(struct folio *folio)
726 {
727 bool ret = test_bit(PG_uptodate, folio_flags(folio, 0));
728 /*
729 * Must ensure that the data we read out of the folio is loaded
730 * _after_ we've loaded folio->flags to check the uptodate bit.
731 * We can skip the barrier if the folio is not uptodate, because
732 * we wouldn't be reading anything from it.
733 *
734 * See folio_mark_uptodate() for the other side of the story.
735 */
736 if (ret)
737 smp_rmb();
738
739 return ret;
740 }
741
PageUptodate(struct page * page)742 static inline int PageUptodate(struct page *page)
743 {
744 return folio_test_uptodate(page_folio(page));
745 }
746
__folio_mark_uptodate(struct folio * folio)747 static __always_inline void __folio_mark_uptodate(struct folio *folio)
748 {
749 smp_wmb();
750 __set_bit(PG_uptodate, folio_flags(folio, 0));
751 }
752
folio_mark_uptodate(struct folio * folio)753 static __always_inline void folio_mark_uptodate(struct folio *folio)
754 {
755 /*
756 * Memory barrier must be issued before setting the PG_uptodate bit,
757 * so that all previous stores issued in order to bring the folio
758 * uptodate are actually visible before folio_test_uptodate becomes true.
759 */
760 smp_wmb();
761 set_bit(PG_uptodate, folio_flags(folio, 0));
762 }
763
__SetPageUptodate(struct page * page)764 static __always_inline void __SetPageUptodate(struct page *page)
765 {
766 __folio_mark_uptodate((struct folio *)page);
767 }
768
SetPageUptodate(struct page * page)769 static __always_inline void SetPageUptodate(struct page *page)
770 {
771 folio_mark_uptodate((struct folio *)page);
772 }
773
774 CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)
775
776 bool __folio_start_writeback(struct folio *folio, bool keep_write);
777 bool set_page_writeback(struct page *page);
778
779 #define folio_start_writeback(folio) \
780 __folio_start_writeback(folio, false)
781 #define folio_start_writeback_keepwrite(folio) \
782 __folio_start_writeback(folio, true)
783
test_set_page_writeback(struct page * page)784 static inline bool test_set_page_writeback(struct page *page)
785 {
786 return set_page_writeback(page);
787 }
788
folio_test_head(struct folio * folio)789 static __always_inline bool folio_test_head(struct folio *folio)
790 {
791 return test_bit(PG_head, folio_flags(folio, FOLIO_PF_ANY));
792 }
793
PageHead(struct page * page)794 static __always_inline int PageHead(struct page *page)
795 {
796 PF_POISONED_CHECK(page);
797 return test_bit(PG_head, &page->flags) && !page_is_fake_head(page);
798 }
799
__SETPAGEFLAG(Head,head,PF_ANY)800 __SETPAGEFLAG(Head, head, PF_ANY)
801 __CLEARPAGEFLAG(Head, head, PF_ANY)
802 CLEARPAGEFLAG(Head, head, PF_ANY)
803
804 /**
805 * folio_test_large() - Does this folio contain more than one page?
806 * @folio: The folio to test.
807 *
808 * Return: True if the folio is larger than one page.
809 */
810 static inline bool folio_test_large(struct folio *folio)
811 {
812 return folio_test_head(folio);
813 }
814
set_compound_head(struct page * page,struct page * head)815 static __always_inline void set_compound_head(struct page *page, struct page *head)
816 {
817 WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
818 }
819
clear_compound_head(struct page * page)820 static __always_inline void clear_compound_head(struct page *page)
821 {
822 WRITE_ONCE(page->compound_head, 0);
823 }
824
825 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
ClearPageCompound(struct page * page)826 static inline void ClearPageCompound(struct page *page)
827 {
828 BUG_ON(!PageHead(page));
829 ClearPageHead(page);
830 }
PAGEFLAG(LargeRmappable,large_rmappable,PF_SECOND)831 PAGEFLAG(LargeRmappable, large_rmappable, PF_SECOND)
832 #else
833 TESTPAGEFLAG_FALSE(LargeRmappable, large_rmappable)
834 #endif
835
836 #define PG_head_mask ((1UL << PG_head))
837
838 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
839 /*
840 * PageHuge() only returns true for hugetlbfs pages, but not for
841 * normal or transparent huge pages.
842 *
843 * PageTransHuge() returns true for both transparent huge and
844 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
845 * called only in the core VM paths where hugetlbfs pages can't exist.
846 */
847 static inline int PageTransHuge(struct page *page)
848 {
849 VM_BUG_ON_PAGE(PageTail(page), page);
850 return PageHead(page);
851 }
852
853 /*
854 * PageTransCompound returns true for both transparent huge pages
855 * and hugetlbfs pages, so it should only be called when it's known
856 * that hugetlbfs pages aren't involved.
857 */
PageTransCompound(struct page * page)858 static inline int PageTransCompound(struct page *page)
859 {
860 return PageCompound(page);
861 }
862
863 /*
864 * PageTransTail returns true for both transparent huge pages
865 * and hugetlbfs pages, so it should only be called when it's known
866 * that hugetlbfs pages aren't involved.
867 */
PageTransTail(struct page * page)868 static inline int PageTransTail(struct page *page)
869 {
870 return PageTail(page);
871 }
872 #else
873 TESTPAGEFLAG_FALSE(TransHuge, transhuge)
874 TESTPAGEFLAG_FALSE(TransCompound, transcompound)
875 TESTPAGEFLAG_FALSE(TransCompoundMap, transcompoundmap)
876 TESTPAGEFLAG_FALSE(TransTail, transtail)
877 #endif
878
879 #if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
880 /*
881 * PageHasHWPoisoned indicates that at least one subpage is hwpoisoned in the
882 * compound page.
883 *
884 * This flag is set by hwpoison handler. Cleared by THP split or free page.
885 */
PAGEFLAG(HasHWPoisoned,has_hwpoisoned,PF_SECOND)886 PAGEFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND)
887 TESTSCFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND)
888 #else
889 PAGEFLAG_FALSE(HasHWPoisoned, has_hwpoisoned)
890 TESTSCFLAG_FALSE(HasHWPoisoned, has_hwpoisoned)
891 #endif
892
893 /*
894 * For pages that are never mapped to userspace (and aren't PageSlab),
895 * page_type may be used. Because it is initialised to -1, we invert the
896 * sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and
897 * __ClearPageFoo *sets* the bit used for PageFoo. We reserve a few high and
898 * low bits so that an underflow or overflow of _mapcount won't be
899 * mistaken for a page type value.
900 */
901
902 #define PAGE_TYPE_BASE 0xf0000000
903 /* Reserve 0x0000007f to catch underflows of _mapcount */
904 #define PAGE_MAPCOUNT_RESERVE -128
905 #define PG_buddy 0x00000080
906 #define PG_offline 0x00000100
907 #define PG_table 0x00000200
908 #define PG_guard 0x00000400
909 #define PG_hugetlb 0x00000800
910
911 #define PageType(page, flag) \
912 ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
913 #define folio_test_type(folio, flag) \
914 ((folio->page.page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
915
916 static inline int page_type_has_type(unsigned int page_type)
917 {
918 return (int)page_type < PAGE_MAPCOUNT_RESERVE;
919 }
920
page_has_type(struct page * page)921 static inline int page_has_type(struct page *page)
922 {
923 return page_type_has_type(page->page_type);
924 }
925
926 #define FOLIO_TYPE_OPS(lname, fname) \
927 static __always_inline bool folio_test_##fname(const struct folio *folio)\
928 { \
929 return folio_test_type(folio, PG_##lname); \
930 } \
931 static __always_inline void __folio_set_##fname(struct folio *folio) \
932 { \
933 VM_BUG_ON_FOLIO(!folio_test_type(folio, 0), folio); \
934 folio->page.page_type &= ~PG_##lname; \
935 } \
936 static __always_inline void __folio_clear_##fname(struct folio *folio) \
937 { \
938 VM_BUG_ON_FOLIO(!folio_test_##fname(folio), folio); \
939 folio->page.page_type |= PG_##lname; \
940 }
941
942 #define PAGE_TYPE_OPS(uname, lname, fname) \
943 FOLIO_TYPE_OPS(lname, fname) \
944 static __always_inline int Page##uname(const struct page *page) \
945 { \
946 return PageType(page, PG_##lname); \
947 } \
948 static __always_inline void __SetPage##uname(struct page *page) \
949 { \
950 VM_BUG_ON_PAGE(!PageType(page, 0), page); \
951 page->page_type &= ~PG_##lname; \
952 } \
953 static __always_inline void __ClearPage##uname(struct page *page) \
954 { \
955 VM_BUG_ON_PAGE(!Page##uname(page), page); \
956 page->page_type |= PG_##lname; \
957 }
958
959 /*
960 * PageBuddy() indicates that the page is free and in the buddy system
961 * (see mm/page_alloc.c).
962 */
963 PAGE_TYPE_OPS(Buddy, buddy, buddy)
964
965 /*
966 * PageOffline() indicates that the page is logically offline although the
967 * containing section is online. (e.g. inflated in a balloon driver or
968 * not onlined when onlining the section).
969 * The content of these pages is effectively stale. Such pages should not
970 * be touched (read/write/dump/save) except by their owner.
971 *
972 * If a driver wants to allow to offline unmovable PageOffline() pages without
973 * putting them back to the buddy, it can do so via the memory notifier by
974 * decrementing the reference count in MEM_GOING_OFFLINE and incrementing the
975 * reference count in MEM_CANCEL_OFFLINE. When offlining, the PageOffline()
976 * pages (now with a reference count of zero) are treated like free pages,
977 * allowing the containing memory block to get offlined. A driver that
978 * relies on this feature is aware that re-onlining the memory block will
979 * require to re-set the pages PageOffline() and not giving them to the
980 * buddy via online_page_callback_t.
981 *
982 * There are drivers that mark a page PageOffline() and expect there won't be
983 * any further access to page content. PFN walkers that read content of random
984 * pages should check PageOffline() and synchronize with such drivers using
985 * page_offline_freeze()/page_offline_thaw().
986 */
987 PAGE_TYPE_OPS(Offline, offline, offline)
988
989 extern void page_offline_freeze(void);
990 extern void page_offline_thaw(void);
991 extern void page_offline_begin(void);
992 extern void page_offline_end(void);
993
994 /*
995 * Marks pages in use as page tables.
996 */
PAGE_TYPE_OPS(Table,table,pgtable)997 PAGE_TYPE_OPS(Table, table, pgtable)
998
999 /*
1000 * Marks guardpages used with debug_pagealloc.
1001 */
1002 PAGE_TYPE_OPS(Guard, guard, guard)
1003
1004 #ifdef CONFIG_HUGETLB_PAGE
1005 FOLIO_TYPE_OPS(hugetlb, hugetlb)
1006 #else
1007 FOLIO_TEST_FLAG_FALSE(hugetlb)
1008 #endif
1009
1010 /**
1011 * PageHuge - Determine if the page belongs to hugetlbfs
1012 * @page: The page to test.
1013 *
1014 * Context: Any context.
1015 * Return: True for hugetlbfs pages, false for anon pages or pages
1016 * belonging to other filesystems.
1017 */
1018 static inline bool PageHuge(const struct page *page)
1019 {
1020 return folio_test_hugetlb(page_folio(page));
1021 }
1022
1023 /*
1024 * Check if a page is currently marked HWPoisoned. Note that this check is
1025 * best effort only and inherently racy: there is no way to synchronize with
1026 * failing hardware.
1027 */
is_page_hwpoison(struct page * page)1028 static inline bool is_page_hwpoison(struct page *page)
1029 {
1030 if (PageHWPoison(page))
1031 return true;
1032 return PageHuge(page) && PageHWPoison(compound_head(page));
1033 }
1034
1035 extern bool is_free_buddy_page(struct page *page);
1036
1037 PAGEFLAG(Isolated, isolated, PF_ANY);
1038
PageAnonExclusive(struct page * page)1039 static __always_inline int PageAnonExclusive(struct page *page)
1040 {
1041 VM_BUG_ON_PGFLAGS(!PageAnon(page), page);
1042 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
1043 return test_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
1044 }
1045
SetPageAnonExclusive(struct page * page)1046 static __always_inline void SetPageAnonExclusive(struct page *page)
1047 {
1048 VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page);
1049 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
1050 set_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
1051 }
1052
ClearPageAnonExclusive(struct page * page)1053 static __always_inline void ClearPageAnonExclusive(struct page *page)
1054 {
1055 VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page);
1056 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
1057 clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
1058 }
1059
__ClearPageAnonExclusive(struct page * page)1060 static __always_inline void __ClearPageAnonExclusive(struct page *page)
1061 {
1062 VM_BUG_ON_PGFLAGS(!PageAnon(page), page);
1063 VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
1064 __clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
1065 }
1066
1067 #ifdef CONFIG_MMU
1068 #define __PG_MLOCKED (1UL << PG_mlocked)
1069 #else
1070 #define __PG_MLOCKED 0
1071 #endif
1072
1073 /*
1074 * Flags checked when a page is freed. Pages being freed should not have
1075 * these flags set. If they are, there is a problem.
1076 */
1077 #define PAGE_FLAGS_CHECK_AT_FREE \
1078 (1UL << PG_lru | 1UL << PG_locked | \
1079 1UL << PG_private | 1UL << PG_private_2 | \
1080 1UL << PG_writeback | 1UL << PG_reserved | \
1081 1UL << PG_slab | 1UL << PG_active | \
1082 1UL << PG_unevictable | __PG_MLOCKED | LRU_GEN_MASK)
1083
1084 /*
1085 * Flags checked when a page is prepped for return by the page allocator.
1086 * Pages being prepped should not have these flags set. If they are set,
1087 * there has been a kernel bug or struct page corruption.
1088 *
1089 * __PG_HWPOISON is exceptional because it needs to be kept beyond page's
1090 * alloc-free cycle to prevent from reusing the page.
1091 */
1092 #define PAGE_FLAGS_CHECK_AT_PREP \
1093 ((PAGEFLAGS_MASK & ~__PG_HWPOISON) | LRU_GEN_MASK | LRU_REFS_MASK)
1094
1095 /*
1096 * Flags stored in the second page of a compound page. They may overlap
1097 * the CHECK_AT_FREE flags above, so need to be cleared.
1098 */
1099 #define PAGE_FLAGS_SECOND \
1100 (0xffUL /* order */ | 1UL << PG_has_hwpoisoned | \
1101 1UL << PG_large_rmappable)
1102
1103 #define PAGE_FLAGS_PRIVATE \
1104 (1UL << PG_private | 1UL << PG_private_2)
1105 /**
1106 * page_has_private - Determine if page has private stuff
1107 * @page: The page to be checked
1108 *
1109 * Determine if a page has private stuff, indicating that release routines
1110 * should be invoked upon it.
1111 */
page_has_private(struct page * page)1112 static inline int page_has_private(struct page *page)
1113 {
1114 return !!(page->flags & PAGE_FLAGS_PRIVATE);
1115 }
1116
folio_has_private(struct folio * folio)1117 static inline bool folio_has_private(struct folio *folio)
1118 {
1119 return page_has_private(&folio->page);
1120 }
1121
1122 #undef PF_ANY
1123 #undef PF_HEAD
1124 #undef PF_ONLY_HEAD
1125 #undef PF_NO_TAIL
1126 #undef PF_NO_COMPOUND
1127 #undef PF_SECOND
1128 #endif /* !__GENERATING_BOUNDS_H */
1129
1130 #endif /* PAGE_FLAGS_H */
1131