Line data Source code
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_referenced,
103 : PG_uptodate,
104 : PG_dirty,
105 : PG_lru,
106 : PG_active,
107 : PG_workingset,
108 : PG_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
109 : PG_error,
110 : PG_slab,
111 : PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
112 : PG_arch_1,
113 : PG_reserved,
114 : PG_private, /* If pagecache, has fs-private data */
115 : PG_private_2, /* If pagecache, has fs aux data */
116 : PG_writeback, /* Page is under writeback */
117 : PG_head, /* A head page */
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 : #ifdef CONFIG_MEMORY_FAILURE
175 : /*
176 : * Compound pages. Stored in first tail page's flags.
177 : * Indicates that at least one subpage is hwpoisoned in the
178 : * THP.
179 : */
180 : PG_has_hwpoisoned = PG_error,
181 : #endif
182 :
183 : /* non-lru isolated movable page */
184 : PG_isolated = PG_reclaim,
185 :
186 : /* Only valid for buddy pages. Used to track pages that are reported */
187 : PG_reported = PG_uptodate,
188 :
189 : #ifdef CONFIG_MEMORY_HOTPLUG
190 : /* For self-hosted memmap pages */
191 : PG_vmemmap_self_hosted = PG_owner_priv_1,
192 : #endif
193 : };
194 :
195 : #define PAGEFLAGS_MASK ((1UL << NR_PAGEFLAGS) - 1)
196 :
197 : #ifndef __GENERATING_BOUNDS_H
198 :
199 : #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
200 : DECLARE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key);
201 :
202 : /*
203 : * Return the real head page struct iff the @page is a fake head page, otherwise
204 : * return the @page itself. See Documentation/mm/vmemmap_dedup.rst.
205 : */
206 : static __always_inline const struct page *page_fixed_fake_head(const struct page *page)
207 : {
208 : if (!static_branch_unlikely(&hugetlb_optimize_vmemmap_key))
209 : return page;
210 :
211 : /*
212 : * Only addresses aligned with PAGE_SIZE of struct page may be fake head
213 : * struct page. The alignment check aims to avoid access the fields (
214 : * e.g. compound_head) of the @page[1]. It can avoid touch a (possibly)
215 : * cold cacheline in some cases.
216 : */
217 : if (IS_ALIGNED((unsigned long)page, PAGE_SIZE) &&
218 : test_bit(PG_head, &page->flags)) {
219 : /*
220 : * We can safely access the field of the @page[1] with PG_head
221 : * because the @page is a compound page composed with at least
222 : * two contiguous pages.
223 : */
224 : unsigned long head = READ_ONCE(page[1].compound_head);
225 :
226 : if (likely(head & 1))
227 : return (const struct page *)(head - 1);
228 : }
229 : return page;
230 : }
231 : #else
232 : static inline const struct page *page_fixed_fake_head(const struct page *page)
233 : {
234 : return page;
235 : }
236 : #endif
237 :
238 : static __always_inline int page_is_fake_head(struct page *page)
239 : {
240 0 : return page_fixed_fake_head(page) != page;
241 : }
242 :
243 0 : static inline unsigned long _compound_head(const struct page *page)
244 : {
245 7657 : unsigned long head = READ_ONCE(page->compound_head);
246 :
247 7657 : if (unlikely(head & 1))
248 1768 : return head - 1;
249 5889 : return (unsigned long)page_fixed_fake_head(page);
250 : }
251 :
252 : #define compound_head(page) ((typeof(page))_compound_head(page))
253 :
254 : /**
255 : * page_folio - Converts from page to folio.
256 : * @p: The page.
257 : *
258 : * Every page is part of a folio. This function cannot be called on a
259 : * NULL pointer.
260 : *
261 : * Context: No reference, nor lock is required on @page. If the caller
262 : * does not hold a reference, this call may race with a folio split, so
263 : * it should re-check the folio still contains this page after gaining
264 : * a reference on the folio.
265 : * Return: The folio which contains this page.
266 : */
267 : #define page_folio(p) (_Generic((p), \
268 : const struct page *: (const struct folio *)_compound_head(p), \
269 : struct page *: (struct folio *)_compound_head(p)))
270 :
271 : /**
272 : * folio_page - Return a page from a folio.
273 : * @folio: The folio.
274 : * @n: The page number to return.
275 : *
276 : * @n is relative to the start of the folio. This function does not
277 : * check that the page number lies within @folio; the caller is presumed
278 : * to have a reference to the page.
279 : */
280 : #define folio_page(folio, n) nth_page(&(folio)->page, n)
281 :
282 : static __always_inline int PageTail(struct page *page)
283 : {
284 0 : return READ_ONCE(page->compound_head) & 1 || page_is_fake_head(page);
285 : }
286 :
287 : static __always_inline int PageCompound(struct page *page)
288 : {
289 774 : return test_bit(PG_head, &page->flags) ||
290 258 : READ_ONCE(page->compound_head) & 1;
291 : }
292 :
293 : #define PAGE_POISON_PATTERN -1l
294 : static inline int PagePoisoned(const struct page *page)
295 : {
296 0 : return READ_ONCE(page->flags) == PAGE_POISON_PATTERN;
297 : }
298 :
299 : #ifdef CONFIG_DEBUG_VM
300 : void page_init_poison(struct page *page, size_t size);
301 : #else
302 : static inline void page_init_poison(struct page *page, size_t size)
303 : {
304 : }
305 : #endif
306 :
307 : static unsigned long *folio_flags(struct folio *folio, unsigned n)
308 : {
309 9110 : struct page *page = &folio->page;
310 :
311 : VM_BUG_ON_PGFLAGS(PageTail(page), page);
312 : VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page);
313 435 : return &page[n].flags;
314 : }
315 :
316 : /*
317 : * Page flags policies wrt compound pages
318 : *
319 : * PF_POISONED_CHECK
320 : * check if this struct page poisoned/uninitialized
321 : *
322 : * PF_ANY:
323 : * the page flag is relevant for small, head and tail pages.
324 : *
325 : * PF_HEAD:
326 : * for compound page all operations related to the page flag applied to
327 : * head page.
328 : *
329 : * PF_ONLY_HEAD:
330 : * for compound page, callers only ever operate on the head page.
331 : *
332 : * PF_NO_TAIL:
333 : * modifications of the page flag must be done on small or head pages,
334 : * checks can be done on tail pages too.
335 : *
336 : * PF_NO_COMPOUND:
337 : * the page flag is not relevant for compound pages.
338 : *
339 : * PF_SECOND:
340 : * the page flag is stored in the first tail page.
341 : */
342 : #define PF_POISONED_CHECK(page) ({ \
343 : VM_BUG_ON_PGFLAGS(PagePoisoned(page), page); \
344 : page; })
345 : #define PF_ANY(page, enforce) PF_POISONED_CHECK(page)
346 : #define PF_HEAD(page, enforce) PF_POISONED_CHECK(compound_head(page))
347 : #define PF_ONLY_HEAD(page, enforce) ({ \
348 : VM_BUG_ON_PGFLAGS(PageTail(page), page); \
349 : PF_POISONED_CHECK(page); })
350 : #define PF_NO_TAIL(page, enforce) ({ \
351 : VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
352 : PF_POISONED_CHECK(compound_head(page)); })
353 : #define PF_NO_COMPOUND(page, enforce) ({ \
354 : VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
355 : PF_POISONED_CHECK(page); })
356 : #define PF_SECOND(page, enforce) ({ \
357 : VM_BUG_ON_PGFLAGS(!PageHead(page), page); \
358 : PF_POISONED_CHECK(&page[1]); })
359 :
360 : /* Which page is the flag stored in */
361 : #define FOLIO_PF_ANY 0
362 : #define FOLIO_PF_HEAD 0
363 : #define FOLIO_PF_ONLY_HEAD 0
364 : #define FOLIO_PF_NO_TAIL 0
365 : #define FOLIO_PF_NO_COMPOUND 0
366 : #define FOLIO_PF_SECOND 1
367 :
368 : /*
369 : * Macros to create function definitions for page flags
370 : */
371 : #define TESTPAGEFLAG(uname, lname, policy) \
372 : static __always_inline bool folio_test_##lname(struct folio *folio) \
373 : { return test_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
374 : static __always_inline int Page##uname(struct page *page) \
375 : { return test_bit(PG_##lname, &policy(page, 0)->flags); }
376 :
377 : #define SETPAGEFLAG(uname, lname, policy) \
378 : static __always_inline \
379 : void folio_set_##lname(struct folio *folio) \
380 : { set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
381 : static __always_inline void SetPage##uname(struct page *page) \
382 : { set_bit(PG_##lname, &policy(page, 1)->flags); }
383 :
384 : #define CLEARPAGEFLAG(uname, lname, policy) \
385 : static __always_inline \
386 : void folio_clear_##lname(struct folio *folio) \
387 : { clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
388 : static __always_inline void ClearPage##uname(struct page *page) \
389 : { clear_bit(PG_##lname, &policy(page, 1)->flags); }
390 :
391 : #define __SETPAGEFLAG(uname, lname, policy) \
392 : static __always_inline \
393 : void __folio_set_##lname(struct folio *folio) \
394 : { __set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
395 : static __always_inline void __SetPage##uname(struct page *page) \
396 : { __set_bit(PG_##lname, &policy(page, 1)->flags); }
397 :
398 : #define __CLEARPAGEFLAG(uname, lname, policy) \
399 : static __always_inline \
400 : void __folio_clear_##lname(struct folio *folio) \
401 : { __clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
402 : static __always_inline void __ClearPage##uname(struct page *page) \
403 : { __clear_bit(PG_##lname, &policy(page, 1)->flags); }
404 :
405 : #define TESTSETFLAG(uname, lname, policy) \
406 : static __always_inline \
407 : bool folio_test_set_##lname(struct folio *folio) \
408 : { return test_and_set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
409 : static __always_inline int TestSetPage##uname(struct page *page) \
410 : { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
411 :
412 : #define TESTCLEARFLAG(uname, lname, policy) \
413 : static __always_inline \
414 : bool folio_test_clear_##lname(struct folio *folio) \
415 : { return test_and_clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
416 : static __always_inline int TestClearPage##uname(struct page *page) \
417 : { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
418 :
419 : #define PAGEFLAG(uname, lname, policy) \
420 : TESTPAGEFLAG(uname, lname, policy) \
421 : SETPAGEFLAG(uname, lname, policy) \
422 : CLEARPAGEFLAG(uname, lname, policy)
423 :
424 : #define __PAGEFLAG(uname, lname, policy) \
425 : TESTPAGEFLAG(uname, lname, policy) \
426 : __SETPAGEFLAG(uname, lname, policy) \
427 : __CLEARPAGEFLAG(uname, lname, policy)
428 :
429 : #define TESTSCFLAG(uname, lname, policy) \
430 : TESTSETFLAG(uname, lname, policy) \
431 : TESTCLEARFLAG(uname, lname, policy)
432 :
433 : #define TESTPAGEFLAG_FALSE(uname, lname) \
434 : static inline bool folio_test_##lname(const struct folio *folio) { return false; } \
435 : static inline int Page##uname(const struct page *page) { return 0; }
436 :
437 : #define SETPAGEFLAG_NOOP(uname, lname) \
438 : static inline void folio_set_##lname(struct folio *folio) { } \
439 : static inline void SetPage##uname(struct page *page) { }
440 :
441 : #define CLEARPAGEFLAG_NOOP(uname, lname) \
442 : static inline void folio_clear_##lname(struct folio *folio) { } \
443 : static inline void ClearPage##uname(struct page *page) { }
444 :
445 : #define __CLEARPAGEFLAG_NOOP(uname, lname) \
446 : static inline void __folio_clear_##lname(struct folio *folio) { } \
447 : static inline void __ClearPage##uname(struct page *page) { }
448 :
449 : #define TESTSETFLAG_FALSE(uname, lname) \
450 : static inline bool folio_test_set_##lname(struct folio *folio) \
451 : { return 0; } \
452 : static inline int TestSetPage##uname(struct page *page) { return 0; }
453 :
454 : #define TESTCLEARFLAG_FALSE(uname, lname) \
455 : static inline bool folio_test_clear_##lname(struct folio *folio) \
456 : { return 0; } \
457 : static inline int TestClearPage##uname(struct page *page) { return 0; }
458 :
459 : #define PAGEFLAG_FALSE(uname, lname) TESTPAGEFLAG_FALSE(uname, lname) \
460 : SETPAGEFLAG_NOOP(uname, lname) CLEARPAGEFLAG_NOOP(uname, lname)
461 :
462 : #define TESTSCFLAG_FALSE(uname, lname) \
463 : TESTSETFLAG_FALSE(uname, lname) TESTCLEARFLAG_FALSE(uname, lname)
464 :
465 0 : __PAGEFLAG(Locked, locked, PF_NO_TAIL)
466 0 : PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD)
467 0 : PAGEFLAG(Error, error, PF_NO_TAIL) TESTCLEARFLAG(Error, error, PF_NO_TAIL)
468 0 : PAGEFLAG(Referenced, referenced, PF_HEAD)
469 0 : TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
470 0 : __SETPAGEFLAG(Referenced, referenced, PF_HEAD)
471 0 : PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
472 : __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
473 0 : PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
474 0 : TESTCLEARFLAG(LRU, lru, PF_HEAD)
475 1844 : PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
476 0 : TESTCLEARFLAG(Active, active, PF_HEAD)
477 0 : PAGEFLAG(Workingset, workingset, PF_HEAD)
478 : TESTCLEARFLAG(Workingset, workingset, PF_HEAD)
479 16184 : __PAGEFLAG(Slab, slab, PF_NO_TAIL)
480 0 : PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */
481 :
482 : /* Xen */
483 : PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
484 : TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)
485 : PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
486 : PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
487 : PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
488 : TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
489 :
490 0 : PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
491 509490 : __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
492 21420 : __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
493 0 : PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
494 : __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
495 0 : __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
496 :
497 : /*
498 : * Private page markings that may be used by the filesystem that owns the page
499 : * for its own purposes.
500 : * - PG_private and PG_private_2 cause release_folio() and co to be invoked
501 : */
502 0 : PAGEFLAG(Private, private, PF_ANY)
503 0 : PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY)
504 : PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
505 : TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
506 :
507 : /*
508 : * Only test-and-set exist for PG_writeback. The unconditional operators are
509 : * risky: they bypass page accounting.
510 : */
511 0 : TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL)
512 0 : TESTSCFLAG(Writeback, writeback, PF_NO_TAIL)
513 0 : PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL)
514 :
515 : /* PG_readahead is only used for reads; PG_reclaim is only for writes */
516 0 : PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL)
517 : TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL)
518 0 : PAGEFLAG(Readahead, readahead, PF_NO_COMPOUND)
519 0 : TESTCLEARFLAG(Readahead, readahead, PF_NO_COMPOUND)
520 :
521 : #ifdef CONFIG_HIGHMEM
522 : /*
523 : * Must use a macro here due to header dependency issues. page_zone() is not
524 : * available at this point.
525 : */
526 : #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
527 : #define folio_test_highmem(__f) is_highmem_idx(folio_zonenum(__f))
528 : #else
529 : PAGEFLAG_FALSE(HighMem, highmem)
530 : #endif
531 :
532 : #ifdef CONFIG_SWAP
533 : static __always_inline bool folio_test_swapcache(struct folio *folio)
534 : {
535 0 : return folio_test_swapbacked(folio) &&
536 0 : test_bit(PG_swapcache, folio_flags(folio, 0));
537 : }
538 :
539 : static __always_inline bool PageSwapCache(struct page *page)
540 : {
541 0 : return folio_test_swapcache(page_folio(page));
542 : }
543 :
544 0 : SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
545 0 : CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
546 : #else
547 : PAGEFLAG_FALSE(SwapCache, swapcache)
548 : #endif
549 :
550 0 : PAGEFLAG(Unevictable, unevictable, PF_HEAD)
551 0 : __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD)
552 0 : TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD)
553 :
554 : #ifdef CONFIG_MMU
555 0 : PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
556 0 : __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
557 0 : TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL)
558 : #else
559 : PAGEFLAG_FALSE(Mlocked, mlocked) __CLEARPAGEFLAG_NOOP(Mlocked, mlocked)
560 : TESTSCFLAG_FALSE(Mlocked, mlocked)
561 : #endif
562 :
563 : #ifdef CONFIG_ARCH_USES_PG_UNCACHED
564 : PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND)
565 : #else
566 : PAGEFLAG_FALSE(Uncached, uncached)
567 : #endif
568 :
569 : #ifdef CONFIG_MEMORY_FAILURE
570 : PAGEFLAG(HWPoison, hwpoison, PF_ANY)
571 : TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
572 : #define __PG_HWPOISON (1UL << PG_hwpoison)
573 : #define MAGIC_HWPOISON 0x48575053U /* HWPS */
574 : extern void SetPageHWPoisonTakenOff(struct page *page);
575 : extern void ClearPageHWPoisonTakenOff(struct page *page);
576 : extern bool take_page_off_buddy(struct page *page);
577 : extern bool put_page_back_buddy(struct page *page);
578 : #else
579 : PAGEFLAG_FALSE(HWPoison, hwpoison)
580 : #define __PG_HWPOISON 0
581 : #endif
582 :
583 : #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT)
584 : TESTPAGEFLAG(Young, young, PF_ANY)
585 : SETPAGEFLAG(Young, young, PF_ANY)
586 : TESTCLEARFLAG(Young, young, PF_ANY)
587 : PAGEFLAG(Idle, idle, PF_ANY)
588 : #endif
589 :
590 : /*
591 : * PageReported() is used to track reported free pages within the Buddy
592 : * allocator. We can use the non-atomic version of the test and set
593 : * operations as both should be shielded with the zone lock to prevent
594 : * any possible races on the setting or clearing of the bit.
595 : */
596 : __PAGEFLAG(Reported, reported, PF_NO_COMPOUND)
597 :
598 : #ifdef CONFIG_MEMORY_HOTPLUG
599 : PAGEFLAG(VmemmapSelfHosted, vmemmap_self_hosted, PF_ANY)
600 : #else
601 : PAGEFLAG_FALSE(VmemmapSelfHosted, vmemmap_self_hosted)
602 : #endif
603 :
604 : /*
605 : * On an anonymous page mapped into a user virtual memory area,
606 : * page->mapping points to its anon_vma, not to a struct address_space;
607 : * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h.
608 : *
609 : * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
610 : * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON
611 : * bit; and then page->mapping points, not to an anon_vma, but to a private
612 : * structure which KSM associates with that merged page. See ksm.h.
613 : *
614 : * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable
615 : * page and then page->mapping points to a struct movable_operations.
616 : *
617 : * Please note that, confusingly, "page_mapping" refers to the inode
618 : * address_space which maps the page from disk; whereas "page_mapped"
619 : * refers to user virtual address space into which the page is mapped.
620 : *
621 : * For slab pages, since slab reuses the bits in struct page to store its
622 : * internal states, the page->mapping does not exist as such, nor do these
623 : * flags below. So in order to avoid testing non-existent bits, please
624 : * make sure that PageSlab(page) actually evaluates to false before calling
625 : * the following functions (e.g., PageAnon). See mm/slab.h.
626 : */
627 : #define PAGE_MAPPING_ANON 0x1
628 : #define PAGE_MAPPING_MOVABLE 0x2
629 : #define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
630 : #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
631 :
632 : /*
633 : * Different with flags above, this flag is used only for fsdax mode. It
634 : * indicates that this page->mapping is now under reflink case.
635 : */
636 : #define PAGE_MAPPING_DAX_SHARED ((void *)0x1)
637 :
638 : static __always_inline bool folio_mapping_flags(struct folio *folio)
639 : {
640 0 : return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) != 0;
641 : }
642 :
643 : static __always_inline int PageMappingFlags(struct page *page)
644 : {
645 259 : return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0;
646 : }
647 :
648 : static __always_inline bool folio_test_anon(struct folio *folio)
649 : {
650 0 : return ((unsigned long)folio->mapping & PAGE_MAPPING_ANON) != 0;
651 : }
652 :
653 : static __always_inline bool PageAnon(struct page *page)
654 : {
655 0 : return folio_test_anon(page_folio(page));
656 : }
657 :
658 : static __always_inline bool __folio_test_movable(const struct folio *folio)
659 : {
660 0 : return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) ==
661 : PAGE_MAPPING_MOVABLE;
662 : }
663 :
664 : static __always_inline int __PageMovable(struct page *page)
665 : {
666 0 : return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
667 : PAGE_MAPPING_MOVABLE;
668 : }
669 :
670 : #ifdef CONFIG_KSM
671 : /*
672 : * A KSM page is one of those write-protected "shared pages" or "merged pages"
673 : * which KSM maps into multiple mms, wherever identical anonymous page content
674 : * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any
675 : * anon_vma, but to that page's node of the stable tree.
676 : */
677 : static __always_inline bool folio_test_ksm(struct folio *folio)
678 : {
679 : return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) ==
680 : PAGE_MAPPING_KSM;
681 : }
682 :
683 : static __always_inline bool PageKsm(struct page *page)
684 : {
685 : return folio_test_ksm(page_folio(page));
686 : }
687 : #else
688 : TESTPAGEFLAG_FALSE(Ksm, ksm)
689 : #endif
690 :
691 : u64 stable_page_flags(struct page *page);
692 :
693 : /**
694 : * folio_test_uptodate - Is this folio up to date?
695 : * @folio: The folio.
696 : *
697 : * The uptodate flag is set on a folio when every byte in the folio is
698 : * at least as new as the corresponding bytes on storage. Anonymous
699 : * and CoW folios are always uptodate. If the folio is not uptodate,
700 : * some of the bytes in it may be; see the is_partially_uptodate()
701 : * address_space operation.
702 : */
703 : static inline bool folio_test_uptodate(struct folio *folio)
704 : {
705 0 : bool ret = test_bit(PG_uptodate, folio_flags(folio, 0));
706 : /*
707 : * Must ensure that the data we read out of the folio is loaded
708 : * _after_ we've loaded folio->flags to check the uptodate bit.
709 : * We can skip the barrier if the folio is not uptodate, because
710 : * we wouldn't be reading anything from it.
711 : *
712 : * See folio_mark_uptodate() for the other side of the story.
713 : */
714 0 : if (ret)
715 0 : smp_rmb();
716 :
717 : return ret;
718 : }
719 :
720 : static inline int PageUptodate(struct page *page)
721 : {
722 0 : return folio_test_uptodate(page_folio(page));
723 : }
724 :
725 : static __always_inline void __folio_mark_uptodate(struct folio *folio)
726 : {
727 0 : smp_wmb();
728 0 : __set_bit(PG_uptodate, folio_flags(folio, 0));
729 : }
730 :
731 : static __always_inline void folio_mark_uptodate(struct folio *folio)
732 : {
733 : /*
734 : * Memory barrier must be issued before setting the PG_uptodate bit,
735 : * so that all previous stores issued in order to bring the folio
736 : * uptodate are actually visible before folio_test_uptodate becomes true.
737 : */
738 0 : smp_wmb();
739 0 : set_bit(PG_uptodate, folio_flags(folio, 0));
740 : }
741 :
742 : static __always_inline void __SetPageUptodate(struct page *page)
743 : {
744 0 : __folio_mark_uptodate((struct folio *)page);
745 : }
746 :
747 : static __always_inline void SetPageUptodate(struct page *page)
748 : {
749 0 : folio_mark_uptodate((struct folio *)page);
750 : }
751 :
752 0 : CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)
753 :
754 : bool __folio_start_writeback(struct folio *folio, bool keep_write);
755 : bool set_page_writeback(struct page *page);
756 :
757 : #define folio_start_writeback(folio) \
758 : __folio_start_writeback(folio, false)
759 : #define folio_start_writeback_keepwrite(folio) \
760 : __folio_start_writeback(folio, true)
761 :
762 : static inline bool test_set_page_writeback(struct page *page)
763 : {
764 : return set_page_writeback(page);
765 : }
766 :
767 : static __always_inline bool folio_test_head(struct folio *folio)
768 : {
769 192 : return test_bit(PG_head, folio_flags(folio, FOLIO_PF_ANY));
770 : }
771 :
772 : static __always_inline int PageHead(struct page *page)
773 : {
774 : PF_POISONED_CHECK(page);
775 0 : return test_bit(PG_head, &page->flags) && !page_is_fake_head(page);
776 : }
777 :
778 192 : __SETPAGEFLAG(Head, head, PF_ANY)
779 : __CLEARPAGEFLAG(Head, head, PF_ANY)
780 : CLEARPAGEFLAG(Head, head, PF_ANY)
781 :
782 : /**
783 : * folio_test_large() - Does this folio contain more than one page?
784 : * @folio: The folio to test.
785 : *
786 : * Return: True if the folio is larger than one page.
787 : */
788 : static inline bool folio_test_large(struct folio *folio)
789 : {
790 96 : return folio_test_head(folio);
791 : }
792 :
793 : static __always_inline void set_compound_head(struct page *page, struct page *head)
794 : {
795 142 : WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
796 : }
797 :
798 : static __always_inline void clear_compound_head(struct page *page)
799 : {
800 0 : WRITE_ONCE(page->compound_head, 0);
801 : }
802 :
803 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
804 : static inline void ClearPageCompound(struct page *page)
805 : {
806 : BUG_ON(!PageHead(page));
807 : ClearPageHead(page);
808 : }
809 : #endif
810 :
811 : #define PG_head_mask ((1UL << PG_head))
812 :
813 : #ifdef CONFIG_HUGETLB_PAGE
814 : int PageHuge(struct page *page);
815 : bool folio_test_hugetlb(struct folio *folio);
816 : #else
817 : TESTPAGEFLAG_FALSE(Huge, hugetlb)
818 : #endif
819 :
820 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
821 : /*
822 : * PageHuge() only returns true for hugetlbfs pages, but not for
823 : * normal or transparent huge pages.
824 : *
825 : * PageTransHuge() returns true for both transparent huge and
826 : * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
827 : * called only in the core VM paths where hugetlbfs pages can't exist.
828 : */
829 : static inline int PageTransHuge(struct page *page)
830 : {
831 : VM_BUG_ON_PAGE(PageTail(page), page);
832 : return PageHead(page);
833 : }
834 :
835 : static inline bool folio_test_transhuge(struct folio *folio)
836 : {
837 : return folio_test_head(folio);
838 : }
839 :
840 : /*
841 : * PageTransCompound returns true for both transparent huge pages
842 : * and hugetlbfs pages, so it should only be called when it's known
843 : * that hugetlbfs pages aren't involved.
844 : */
845 : static inline int PageTransCompound(struct page *page)
846 : {
847 : return PageCompound(page);
848 : }
849 :
850 : /*
851 : * PageTransTail returns true for both transparent huge pages
852 : * and hugetlbfs pages, so it should only be called when it's known
853 : * that hugetlbfs pages aren't involved.
854 : */
855 : static inline int PageTransTail(struct page *page)
856 : {
857 : return PageTail(page);
858 : }
859 : #else
860 : TESTPAGEFLAG_FALSE(TransHuge, transhuge)
861 : TESTPAGEFLAG_FALSE(TransCompound, transcompound)
862 : TESTPAGEFLAG_FALSE(TransCompoundMap, transcompoundmap)
863 : TESTPAGEFLAG_FALSE(TransTail, transtail)
864 : #endif
865 :
866 : #if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
867 : /*
868 : * PageHasHWPoisoned indicates that at least one subpage is hwpoisoned in the
869 : * compound page.
870 : *
871 : * This flag is set by hwpoison handler. Cleared by THP split or free page.
872 : */
873 : PAGEFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND)
874 : TESTSCFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND)
875 : #else
876 : PAGEFLAG_FALSE(HasHWPoisoned, has_hwpoisoned)
877 : TESTSCFLAG_FALSE(HasHWPoisoned, has_hwpoisoned)
878 : #endif
879 :
880 : /*
881 : * Check if a page is currently marked HWPoisoned. Note that this check is
882 : * best effort only and inherently racy: there is no way to synchronize with
883 : * failing hardware.
884 : */
885 : static inline bool is_page_hwpoison(struct page *page)
886 : {
887 : if (PageHWPoison(page))
888 : return true;
889 : return PageHuge(page) && PageHWPoison(compound_head(page));
890 : }
891 :
892 : /*
893 : * For pages that are never mapped to userspace (and aren't PageSlab),
894 : * page_type may be used. Because it is initialised to -1, we invert the
895 : * sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and
896 : * __ClearPageFoo *sets* the bit used for PageFoo. We reserve a few high and
897 : * low bits so that an underflow or overflow of page_mapcount() won't be
898 : * mistaken for a page type value.
899 : */
900 :
901 : #define PAGE_TYPE_BASE 0xf0000000
902 : /* Reserve 0x0000007f to catch underflows of page_mapcount */
903 : #define PAGE_MAPCOUNT_RESERVE -128
904 : #define PG_buddy 0x00000080
905 : #define PG_offline 0x00000100
906 : #define PG_table 0x00000200
907 : #define PG_guard 0x00000400
908 :
909 : #define PageType(page, flag) \
910 : ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
911 :
912 : static inline int page_type_has_type(unsigned int page_type)
913 : {
914 0 : return (int)page_type < PAGE_MAPCOUNT_RESERVE;
915 : }
916 :
917 : static inline int page_has_type(struct page *page)
918 : {
919 0 : return page_type_has_type(page->page_type);
920 : }
921 :
922 : #define PAGE_TYPE_OPS(uname, lname) \
923 : static __always_inline int Page##uname(struct page *page) \
924 : { \
925 : return PageType(page, PG_##lname); \
926 : } \
927 : static __always_inline void __SetPage##uname(struct page *page) \
928 : { \
929 : VM_BUG_ON_PAGE(!PageType(page, 0), page); \
930 : page->page_type &= ~PG_##lname; \
931 : } \
932 : static __always_inline void __ClearPage##uname(struct page *page) \
933 : { \
934 : VM_BUG_ON_PAGE(!Page##uname(page), page); \
935 : page->page_type |= PG_##lname; \
936 : }
937 :
938 : /*
939 : * PageBuddy() indicates that the page is free and in the buddy system
940 : * (see mm/page_alloc.c).
941 : */
942 1631 : PAGE_TYPE_OPS(Buddy, buddy)
943 :
944 : /*
945 : * PageOffline() indicates that the page is logically offline although the
946 : * containing section is online. (e.g. inflated in a balloon driver or
947 : * not onlined when onlining the section).
948 : * The content of these pages is effectively stale. Such pages should not
949 : * be touched (read/write/dump/save) except by their owner.
950 : *
951 : * If a driver wants to allow to offline unmovable PageOffline() pages without
952 : * putting them back to the buddy, it can do so via the memory notifier by
953 : * decrementing the reference count in MEM_GOING_OFFLINE and incrementing the
954 : * reference count in MEM_CANCEL_OFFLINE. When offlining, the PageOffline()
955 : * pages (now with a reference count of zero) are treated like free pages,
956 : * allowing the containing memory block to get offlined. A driver that
957 : * relies on this feature is aware that re-onlining the memory block will
958 : * require to re-set the pages PageOffline() and not giving them to the
959 : * buddy via online_page_callback_t.
960 : *
961 : * There are drivers that mark a page PageOffline() and expect there won't be
962 : * any further access to page content. PFN walkers that read content of random
963 : * pages should check PageOffline() and synchronize with such drivers using
964 : * page_offline_freeze()/page_offline_thaw().
965 : */
966 0 : PAGE_TYPE_OPS(Offline, offline)
967 :
968 : extern void page_offline_freeze(void);
969 : extern void page_offline_thaw(void);
970 : extern void page_offline_begin(void);
971 : extern void page_offline_end(void);
972 :
973 : /*
974 : * Marks pages in use as page tables.
975 : */
976 1 : PAGE_TYPE_OPS(Table, table)
977 :
978 : /*
979 : * Marks guardpages used with debug_pagealloc.
980 : */
981 : PAGE_TYPE_OPS(Guard, guard)
982 :
983 : extern bool is_free_buddy_page(struct page *page);
984 :
985 0 : PAGEFLAG(Isolated, isolated, PF_ANY);
986 :
987 : static __always_inline int PageAnonExclusive(struct page *page)
988 : {
989 : VM_BUG_ON_PGFLAGS(!PageAnon(page), page);
990 : VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
991 0 : return test_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
992 : }
993 :
994 : static __always_inline void SetPageAnonExclusive(struct page *page)
995 : {
996 : VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page);
997 : VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
998 0 : set_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
999 : }
1000 :
1001 : static __always_inline void ClearPageAnonExclusive(struct page *page)
1002 : {
1003 : VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page);
1004 : VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
1005 0 : clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
1006 : }
1007 :
1008 : static __always_inline void __ClearPageAnonExclusive(struct page *page)
1009 : {
1010 : VM_BUG_ON_PGFLAGS(!PageAnon(page), page);
1011 : VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
1012 : __clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
1013 : }
1014 :
1015 : #ifdef CONFIG_MMU
1016 : #define __PG_MLOCKED (1UL << PG_mlocked)
1017 : #else
1018 : #define __PG_MLOCKED 0
1019 : #endif
1020 :
1021 : /*
1022 : * Flags checked when a page is freed. Pages being freed should not have
1023 : * these flags set. If they are, there is a problem.
1024 : */
1025 : #define PAGE_FLAGS_CHECK_AT_FREE \
1026 : (1UL << PG_lru | 1UL << PG_locked | \
1027 : 1UL << PG_private | 1UL << PG_private_2 | \
1028 : 1UL << PG_writeback | 1UL << PG_reserved | \
1029 : 1UL << PG_slab | 1UL << PG_active | \
1030 : 1UL << PG_unevictable | __PG_MLOCKED | LRU_GEN_MASK)
1031 :
1032 : /*
1033 : * Flags checked when a page is prepped for return by the page allocator.
1034 : * Pages being prepped should not have these flags set. If they are set,
1035 : * there has been a kernel bug or struct page corruption.
1036 : *
1037 : * __PG_HWPOISON is exceptional because it needs to be kept beyond page's
1038 : * alloc-free cycle to prevent from reusing the page.
1039 : */
1040 : #define PAGE_FLAGS_CHECK_AT_PREP \
1041 : ((PAGEFLAGS_MASK & ~__PG_HWPOISON) | LRU_GEN_MASK | LRU_REFS_MASK)
1042 :
1043 : #define PAGE_FLAGS_PRIVATE \
1044 : (1UL << PG_private | 1UL << PG_private_2)
1045 : /**
1046 : * page_has_private - Determine if page has private stuff
1047 : * @page: The page to be checked
1048 : *
1049 : * Determine if a page has private stuff, indicating that release routines
1050 : * should be invoked upon it.
1051 : */
1052 : static inline int page_has_private(struct page *page)
1053 : {
1054 0 : return !!(page->flags & PAGE_FLAGS_PRIVATE);
1055 : }
1056 :
1057 : static inline bool folio_has_private(struct folio *folio)
1058 : {
1059 0 : return page_has_private(&folio->page);
1060 : }
1061 :
1062 : #undef PF_ANY
1063 : #undef PF_HEAD
1064 : #undef PF_ONLY_HEAD
1065 : #undef PF_NO_TAIL
1066 : #undef PF_NO_COMPOUND
1067 : #undef PF_SECOND
1068 : #endif /* !__GENERATING_BOUNDS_H */
1069 :
1070 : #endif /* PAGE_FLAGS_H */
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