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_uptodate tells whether the page's contents is valid. When a read
72 : * completes, the page becomes uptodate, unless a disk I/O error happened.
73 : *
74 : * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
75 : * file-backed pagecache (see mm/vmscan.c).
76 : *
77 : * PG_error is set to indicate that an I/O error occurred on this page.
78 : *
79 : * PG_arch_1 is an architecture specific page state bit. The generic code
80 : * guarantees that this bit is cleared for a page when it first is entered into
81 : * the page cache.
82 : *
83 : * PG_hwpoison indicates that a page got corrupted in hardware and contains
84 : * data with incorrect ECC bits that triggered a machine check. Accessing is
85 : * not safe since it may cause another machine check. Don't touch!
86 : */
87 :
88 : /*
89 : * Don't use the pageflags directly. Use the PageFoo macros.
90 : *
91 : * The page flags field is split into two parts, the main flags area
92 : * which extends from the low bits upwards, and the fields area which
93 : * extends from the high bits downwards.
94 : *
95 : * | FIELD | ... | FLAGS |
96 : * N-1 ^ 0
97 : * (NR_PAGEFLAGS)
98 : *
99 : * The fields area is reserved for fields mapping zone, node (for NUMA) and
100 : * SPARSEMEM section (for variants of SPARSEMEM that require section ids like
101 : * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
102 : */
103 : enum pageflags {
104 : PG_locked, /* Page is locked. Don't touch. */
105 : PG_referenced,
106 : PG_uptodate,
107 : PG_dirty,
108 : PG_lru,
109 : PG_active,
110 : PG_workingset,
111 : PG_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
112 : PG_error,
113 : PG_slab,
114 : PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
115 : PG_arch_1,
116 : PG_reserved,
117 : PG_private, /* If pagecache, has fs-private data */
118 : PG_private_2, /* If pagecache, has fs aux data */
119 : PG_writeback, /* Page is under writeback */
120 : PG_head, /* A head page */
121 : PG_mappedtodisk, /* Has blocks allocated on-disk */
122 : PG_reclaim, /* To be reclaimed asap */
123 : PG_swapbacked, /* Page is backed by RAM/swap */
124 : PG_unevictable, /* Page is "unevictable" */
125 : #ifdef CONFIG_MMU
126 : PG_mlocked, /* Page is vma mlocked */
127 : #endif
128 : #ifdef CONFIG_ARCH_USES_PG_UNCACHED
129 : PG_uncached, /* Page has been mapped as uncached */
130 : #endif
131 : #ifdef CONFIG_MEMORY_FAILURE
132 : PG_hwpoison, /* hardware poisoned page. Don't touch */
133 : #endif
134 : #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
135 : PG_young,
136 : PG_idle,
137 : #endif
138 : #ifdef CONFIG_64BIT
139 : PG_arch_2,
140 : #endif
141 : __NR_PAGEFLAGS,
142 :
143 : /* Filesystems */
144 : PG_checked = PG_owner_priv_1,
145 :
146 : /* SwapBacked */
147 : PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */
148 :
149 : /* Two page bits are conscripted by FS-Cache to maintain local caching
150 : * state. These bits are set on pages belonging to the netfs's inodes
151 : * when those inodes are being locally cached.
152 : */
153 : PG_fscache = PG_private_2, /* page backed by cache */
154 :
155 : /* XEN */
156 : /* Pinned in Xen as a read-only pagetable page. */
157 : PG_pinned = PG_owner_priv_1,
158 : /* Pinned as part of domain save (see xen_mm_pin_all()). */
159 : PG_savepinned = PG_dirty,
160 : /* Has a grant mapping of another (foreign) domain's page. */
161 : PG_foreign = PG_owner_priv_1,
162 : /* Remapped by swiotlb-xen. */
163 : PG_xen_remapped = PG_owner_priv_1,
164 :
165 : /* SLOB */
166 : PG_slob_free = PG_private,
167 :
168 : /* Compound pages. Stored in first tail page's flags */
169 : PG_double_map = PG_workingset,
170 :
171 : /* non-lru isolated movable page */
172 : PG_isolated = PG_reclaim,
173 :
174 : /* Only valid for buddy pages. Used to track pages that are reported */
175 : PG_reported = PG_uptodate,
176 : };
177 :
178 : #ifndef __GENERATING_BOUNDS_H
179 :
180 : struct page; /* forward declaration */
181 :
182 19901558 : static inline struct page *compound_head(struct page *page)
183 : {
184 19901558 : unsigned long head = READ_ONCE(page->compound_head);
185 :
186 11748467 : if (unlikely(head & 1))
187 2219363 : return (struct page *) (head - 1);
188 : return page;
189 : }
190 :
191 2569831 : static __always_inline int PageTail(struct page *page)
192 : {
193 2547225 : return READ_ONCE(page->compound_head) & 1;
194 : }
195 :
196 2093068 : static __always_inline int PageCompound(struct page *page)
197 : {
198 2093049 : return test_bit(PG_head, &page->flags) || PageTail(page);
199 : }
200 :
201 : #define PAGE_POISON_PATTERN -1l
202 0 : static inline int PagePoisoned(const struct page *page)
203 : {
204 0 : return page->flags == PAGE_POISON_PATTERN;
205 : }
206 :
207 : #ifdef CONFIG_DEBUG_VM
208 : void page_init_poison(struct page *page, size_t size);
209 : #else
210 : static inline void page_init_poison(struct page *page, size_t size)
211 : {
212 : }
213 : #endif
214 :
215 : /*
216 : * Page flags policies wrt compound pages
217 : *
218 : * PF_POISONED_CHECK
219 : * check if this struct page poisoned/uninitialized
220 : *
221 : * PF_ANY:
222 : * the page flag is relevant for small, head and tail pages.
223 : *
224 : * PF_HEAD:
225 : * for compound page all operations related to the page flag applied to
226 : * head page.
227 : *
228 : * PF_ONLY_HEAD:
229 : * for compound page, callers only ever operate on the head page.
230 : *
231 : * PF_NO_TAIL:
232 : * modifications of the page flag must be done on small or head pages,
233 : * checks can be done on tail pages too.
234 : *
235 : * PF_NO_COMPOUND:
236 : * the page flag is not relevant for compound pages.
237 : *
238 : * PF_SECOND:
239 : * the page flag is stored in the first tail page.
240 : */
241 : #define PF_POISONED_CHECK(page) ({ \
242 : VM_BUG_ON_PGFLAGS(PagePoisoned(page), page); \
243 : page; })
244 : #define PF_ANY(page, enforce) PF_POISONED_CHECK(page)
245 : #define PF_HEAD(page, enforce) PF_POISONED_CHECK(compound_head(page))
246 : #define PF_ONLY_HEAD(page, enforce) ({ \
247 : VM_BUG_ON_PGFLAGS(PageTail(page), page); \
248 : PF_POISONED_CHECK(page); })
249 : #define PF_NO_TAIL(page, enforce) ({ \
250 : VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
251 : PF_POISONED_CHECK(compound_head(page)); })
252 : #define PF_NO_COMPOUND(page, enforce) ({ \
253 : VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
254 : PF_POISONED_CHECK(page); })
255 : #define PF_SECOND(page, enforce) ({ \
256 : VM_BUG_ON_PGFLAGS(!PageHead(page), page); \
257 : PF_POISONED_CHECK(&page[1]); })
258 :
259 : /*
260 : * Macros to create function definitions for page flags
261 : */
262 : #define TESTPAGEFLAG(uname, lname, policy) \
263 : static __always_inline int Page##uname(struct page *page) \
264 : { return test_bit(PG_##lname, &policy(page, 0)->flags); }
265 :
266 : #define SETPAGEFLAG(uname, lname, policy) \
267 : static __always_inline void SetPage##uname(struct page *page) \
268 : { set_bit(PG_##lname, &policy(page, 1)->flags); }
269 :
270 : #define CLEARPAGEFLAG(uname, lname, policy) \
271 : static __always_inline void ClearPage##uname(struct page *page) \
272 : { clear_bit(PG_##lname, &policy(page, 1)->flags); }
273 :
274 : #define __SETPAGEFLAG(uname, lname, policy) \
275 : static __always_inline void __SetPage##uname(struct page *page) \
276 : { __set_bit(PG_##lname, &policy(page, 1)->flags); }
277 :
278 : #define __CLEARPAGEFLAG(uname, lname, policy) \
279 : static __always_inline void __ClearPage##uname(struct page *page) \
280 : { __clear_bit(PG_##lname, &policy(page, 1)->flags); }
281 :
282 : #define TESTSETFLAG(uname, lname, policy) \
283 : static __always_inline int TestSetPage##uname(struct page *page) \
284 : { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
285 :
286 : #define TESTCLEARFLAG(uname, lname, policy) \
287 : static __always_inline int TestClearPage##uname(struct page *page) \
288 : { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
289 :
290 : #define PAGEFLAG(uname, lname, policy) \
291 : TESTPAGEFLAG(uname, lname, policy) \
292 : SETPAGEFLAG(uname, lname, policy) \
293 : CLEARPAGEFLAG(uname, lname, policy)
294 :
295 : #define __PAGEFLAG(uname, lname, policy) \
296 : TESTPAGEFLAG(uname, lname, policy) \
297 : __SETPAGEFLAG(uname, lname, policy) \
298 : __CLEARPAGEFLAG(uname, lname, policy)
299 :
300 : #define TESTSCFLAG(uname, lname, policy) \
301 : TESTSETFLAG(uname, lname, policy) \
302 : TESTCLEARFLAG(uname, lname, policy)
303 :
304 : #define TESTPAGEFLAG_FALSE(uname) \
305 : static inline int Page##uname(const struct page *page) { return 0; }
306 :
307 : #define SETPAGEFLAG_NOOP(uname) \
308 : static inline void SetPage##uname(struct page *page) { }
309 :
310 : #define CLEARPAGEFLAG_NOOP(uname) \
311 : static inline void ClearPage##uname(struct page *page) { }
312 :
313 : #define __CLEARPAGEFLAG_NOOP(uname) \
314 : static inline void __ClearPage##uname(struct page *page) { }
315 :
316 : #define TESTSETFLAG_FALSE(uname) \
317 : static inline int TestSetPage##uname(struct page *page) { return 0; }
318 :
319 : #define TESTCLEARFLAG_FALSE(uname) \
320 : static inline int TestClearPage##uname(struct page *page) { return 0; }
321 :
322 : #define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \
323 : SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname)
324 :
325 : #define TESTSCFLAG_FALSE(uname) \
326 : TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
327 :
328 53497 : __PAGEFLAG(Locked, locked, PF_NO_TAIL)
329 161957 : PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) __CLEARPAGEFLAG(Waiters, waiters, PF_ONLY_HEAD)
330 21545 : PAGEFLAG(Error, error, PF_NO_TAIL) TESTCLEARFLAG(Error, error, PF_NO_TAIL)
331 803935 : PAGEFLAG(Referenced, referenced, PF_HEAD)
332 0 : TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
333 2694 : __SETPAGEFLAG(Referenced, referenced, PF_HEAD)
334 16812 : PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
335 : __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
336 545626 : PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
337 17394 : TESTCLEARFLAG(LRU, lru, PF_HEAD)
338 2071475 : PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
339 0 : TESTCLEARFLAG(Active, active, PF_HEAD)
340 12588 : PAGEFLAG(Workingset, workingset, PF_HEAD)
341 : TESTCLEARFLAG(Workingset, workingset, PF_HEAD)
342 1666758 : __PAGEFLAG(Slab, slab, PF_NO_TAIL)
343 : __PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
344 496 : PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */
345 :
346 : /* Xen */
347 : PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
348 : TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)
349 : PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
350 : PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
351 : PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
352 : TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
353 :
354 1078 : PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
355 405384 : __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
356 381164 : __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
357 1745627 : PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
358 : __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
359 140248 : __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
360 :
361 : /*
362 : * Private page markings that may be used by the filesystem that owns the page
363 : * for its own purposes.
364 : * - PG_private and PG_private_2 cause releasepage() and co to be invoked
365 : */
366 65696 : PAGEFLAG(Private, private, PF_ANY)
367 : PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY)
368 : PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
369 : TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
370 :
371 : /*
372 : * Only test-and-set exist for PG_writeback. The unconditional operators are
373 : * risky: they bypass page accounting.
374 : */
375 7901 : TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL)
376 2568 : TESTSCFLAG(Writeback, writeback, PF_NO_TAIL)
377 23525 : PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL)
378 :
379 : /* PG_readahead is only used for reads; PG_reclaim is only for writes */
380 3061 : PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL)
381 : TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL)
382 1817 : PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND)
383 : TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND)
384 :
385 : #ifdef CONFIG_HIGHMEM
386 : /*
387 : * Must use a macro here due to header dependency issues. page_zone() is not
388 : * available at this point.
389 : */
390 : #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
391 : #else
392 501999 : PAGEFLAG_FALSE(HighMem)
393 : #endif
394 :
395 : #ifdef CONFIG_SWAP
396 : static __always_inline int PageSwapCache(struct page *page)
397 : {
398 : #ifdef CONFIG_THP_SWAP
399 : page = compound_head(page);
400 : #endif
401 : return PageSwapBacked(page) && test_bit(PG_swapcache, &page->flags);
402 :
403 : }
404 : SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
405 : CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
406 : #else
407 116307 : PAGEFLAG_FALSE(SwapCache)
408 : #endif
409 :
410 979296 : PAGEFLAG(Unevictable, unevictable, PF_HEAD)
411 129996 : __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD)
412 96343 : TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD)
413 :
414 : #ifdef CONFIG_MMU
415 259463 : PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
416 : __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
417 47 : TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL)
418 : #else
419 : PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked)
420 : TESTSCFLAG_FALSE(Mlocked)
421 : #endif
422 :
423 : #ifdef CONFIG_ARCH_USES_PG_UNCACHED
424 : PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND)
425 : #else
426 : PAGEFLAG_FALSE(Uncached)
427 : #endif
428 :
429 : #ifdef CONFIG_MEMORY_FAILURE
430 : PAGEFLAG(HWPoison, hwpoison, PF_ANY)
431 : TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
432 : #define __PG_HWPOISON (1UL << PG_hwpoison)
433 : extern bool take_page_off_buddy(struct page *page);
434 : #else
435 158924 : PAGEFLAG_FALSE(HWPoison)
436 : #define __PG_HWPOISON 0
437 : #endif
438 :
439 : #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
440 : TESTPAGEFLAG(Young, young, PF_ANY)
441 : SETPAGEFLAG(Young, young, PF_ANY)
442 : TESTCLEARFLAG(Young, young, PF_ANY)
443 : PAGEFLAG(Idle, idle, PF_ANY)
444 : #endif
445 :
446 : /*
447 : * PageReported() is used to track reported free pages within the Buddy
448 : * allocator. We can use the non-atomic version of the test and set
449 : * operations as both should be shielded with the zone lock to prevent
450 : * any possible races on the setting or clearing of the bit.
451 : */
452 97180 : __PAGEFLAG(Reported, reported, PF_NO_COMPOUND)
453 :
454 : /*
455 : * On an anonymous page mapped into a user virtual memory area,
456 : * page->mapping points to its anon_vma, not to a struct address_space;
457 : * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h.
458 : *
459 : * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
460 : * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON
461 : * bit; and then page->mapping points, not to an anon_vma, but to a private
462 : * structure which KSM associates with that merged page. See ksm.h.
463 : *
464 : * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable
465 : * page and then page->mapping points a struct address_space.
466 : *
467 : * Please note that, confusingly, "page_mapping" refers to the inode
468 : * address_space which maps the page from disk; whereas "page_mapped"
469 : * refers to user virtual address space into which the page is mapped.
470 : */
471 : #define PAGE_MAPPING_ANON 0x1
472 : #define PAGE_MAPPING_MOVABLE 0x2
473 : #define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
474 : #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
475 :
476 148341 : static __always_inline int PageMappingFlags(struct page *page)
477 : {
478 148341 : return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0;
479 : }
480 :
481 2906455 : static __always_inline int PageAnon(struct page *page)
482 : {
483 2906455 : page = compound_head(page);
484 2906465 : return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
485 : }
486 :
487 0 : static __always_inline int __PageMovable(struct page *page)
488 : {
489 0 : return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
490 : PAGE_MAPPING_MOVABLE;
491 : }
492 :
493 : #ifdef CONFIG_KSM
494 : /*
495 : * A KSM page is one of those write-protected "shared pages" or "merged pages"
496 : * which KSM maps into multiple mms, wherever identical anonymous page content
497 : * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any
498 : * anon_vma, but to that page's node of the stable tree.
499 : */
500 50600 : static __always_inline int PageKsm(struct page *page)
501 : {
502 50600 : page = compound_head(page);
503 50600 : return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
504 : PAGE_MAPPING_KSM;
505 : }
506 : #else
507 : TESTPAGEFLAG_FALSE(Ksm)
508 : #endif
509 :
510 : u64 stable_page_flags(struct page *page);
511 :
512 35254 : static inline int PageUptodate(struct page *page)
513 : {
514 35254 : int ret;
515 35254 : page = compound_head(page);
516 35254 : ret = test_bit(PG_uptodate, &(page)->flags);
517 : /*
518 : * Must ensure that the data we read out of the page is loaded
519 : * _after_ we've loaded page->flags to check for PageUptodate.
520 : * We can skip the barrier if the page is not uptodate, because
521 : * we wouldn't be reading anything from it.
522 : *
523 : * See SetPageUptodate() for the other side of the story.
524 : */
525 35254 : if (ret)
526 3855 : smp_rmb();
527 :
528 35254 : return ret;
529 : }
530 :
531 68316 : static __always_inline void __SetPageUptodate(struct page *page)
532 : {
533 68316 : VM_BUG_ON_PAGE(PageTail(page), page);
534 68316 : smp_wmb();
535 136632 : __set_bit(PG_uptodate, &page->flags);
536 : }
537 :
538 24369 : static __always_inline void SetPageUptodate(struct page *page)
539 : {
540 24369 : VM_BUG_ON_PAGE(PageTail(page), page);
541 : /*
542 : * Memory barrier must be issued before setting the PG_uptodate bit,
543 : * so that all previous stores issued in order to bring the page
544 : * uptodate are actually visible before PageUptodate becomes true.
545 : */
546 24369 : smp_wmb();
547 24369 : set_bit(PG_uptodate, &page->flags);
548 24322 : }
549 :
550 0 : CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)
551 :
552 : int test_clear_page_writeback(struct page *page);
553 : int __test_set_page_writeback(struct page *page, bool keep_write);
554 :
555 : #define test_set_page_writeback(page) \
556 : __test_set_page_writeback(page, false)
557 : #define test_set_page_writeback_keepwrite(page) \
558 : __test_set_page_writeback(page, true)
559 :
560 1386 : static inline void set_page_writeback(struct page *page)
561 : {
562 1386 : test_set_page_writeback(page);
563 1386 : }
564 :
565 0 : static inline void set_page_writeback_keepwrite(struct page *page)
566 : {
567 0 : test_set_page_writeback_keepwrite(page);
568 0 : }
569 :
570 610552 : __PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY)
571 :
572 85991 : static __always_inline void set_compound_head(struct page *page, struct page *head)
573 : {
574 85991 : WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
575 : }
576 :
577 68885 : static __always_inline void clear_compound_head(struct page *page)
578 : {
579 68885 : WRITE_ONCE(page->compound_head, 0);
580 : }
581 :
582 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
583 0 : static inline void ClearPageCompound(struct page *page)
584 : {
585 0 : BUG_ON(!PageHead(page));
586 0 : ClearPageHead(page);
587 0 : }
588 : #endif
589 :
590 : #define PG_head_mask ((1UL << PG_head))
591 :
592 : #ifdef CONFIG_HUGETLB_PAGE
593 : int PageHuge(struct page *page);
594 : int PageHeadHuge(struct page *page);
595 : #else
596 776511 : TESTPAGEFLAG_FALSE(Huge)
597 136 : TESTPAGEFLAG_FALSE(HeadHuge)
598 : #endif
599 :
600 :
601 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
602 : /*
603 : * PageHuge() only returns true for hugetlbfs pages, but not for
604 : * normal or transparent huge pages.
605 : *
606 : * PageTransHuge() returns true for both transparent huge and
607 : * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
608 : * called only in the core VM paths where hugetlbfs pages can't exist.
609 : */
610 6045 : static inline int PageTransHuge(struct page *page)
611 : {
612 6045 : VM_BUG_ON_PAGE(PageTail(page), page);
613 6045 : return PageHead(page);
614 : }
615 :
616 : /*
617 : * PageTransCompound returns true for both transparent huge pages
618 : * and hugetlbfs pages, so it should only be called when it's known
619 : * that hugetlbfs pages aren't involved.
620 : */
621 935505 : static inline int PageTransCompound(struct page *page)
622 : {
623 935505 : return PageCompound(page);
624 : }
625 :
626 : /*
627 : * PageTransCompoundMap is the same as PageTransCompound, but it also
628 : * guarantees the primary MMU has the entire compound page mapped
629 : * through pmd_trans_huge, which in turn guarantees the secondary MMUs
630 : * can also map the entire compound page. This allows the secondary
631 : * MMUs to call get_user_pages() only once for each compound page and
632 : * to immediately map the entire compound page with a single secondary
633 : * MMU fault. If there will be a pmd split later, the secondary MMUs
634 : * will get an update through the MMU notifier invalidation through
635 : * split_huge_pmd().
636 : *
637 : * Unlike PageTransCompound, this is safe to be called only while
638 : * split_huge_pmd() cannot run from under us, like if protected by the
639 : * MMU notifier, otherwise it may result in page->_mapcount check false
640 : * positives.
641 : *
642 : * We have to treat page cache THP differently since every subpage of it
643 : * would get _mapcount inc'ed once it is PMD mapped. But, it may be PTE
644 : * mapped in the current process so comparing subpage's _mapcount to
645 : * compound_mapcount to filter out PTE mapped case.
646 : */
647 : static inline int PageTransCompoundMap(struct page *page)
648 : {
649 : struct page *head;
650 :
651 : if (!PageTransCompound(page))
652 : return 0;
653 :
654 : if (PageAnon(page))
655 : return atomic_read(&page->_mapcount) < 0;
656 :
657 : head = compound_head(page);
658 : /* File THP is PMD mapped and not PTE mapped */
659 : return atomic_read(&page->_mapcount) ==
660 : atomic_read(compound_mapcount_ptr(head));
661 : }
662 :
663 : /*
664 : * PageTransTail returns true for both transparent huge pages
665 : * and hugetlbfs pages, so it should only be called when it's known
666 : * that hugetlbfs pages aren't involved.
667 : */
668 138 : static inline int PageTransTail(struct page *page)
669 : {
670 138 : return PageTail(page);
671 : }
672 :
673 : /*
674 : * PageDoubleMap indicates that the compound page is mapped with PTEs as well
675 : * as PMDs.
676 : *
677 : * This is required for optimization of rmap operations for THP: we can postpone
678 : * per small page mapcount accounting (and its overhead from atomic operations)
679 : * until the first PMD split.
680 : *
681 : * For the page PageDoubleMap means ->_mapcount in all sub-pages is offset up
682 : * by one. This reference will go away with last compound_mapcount.
683 : *
684 : * See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap().
685 : */
686 13494 : PAGEFLAG(DoubleMap, double_map, PF_SECOND)
687 19 : TESTSCFLAG(DoubleMap, double_map, PF_SECOND)
688 : #else
689 : TESTPAGEFLAG_FALSE(TransHuge)
690 : TESTPAGEFLAG_FALSE(TransCompound)
691 : TESTPAGEFLAG_FALSE(TransCompoundMap)
692 : TESTPAGEFLAG_FALSE(TransTail)
693 : PAGEFLAG_FALSE(DoubleMap)
694 : TESTSCFLAG_FALSE(DoubleMap)
695 : #endif
696 :
697 : /*
698 : * For pages that are never mapped to userspace (and aren't PageSlab),
699 : * page_type may be used. Because it is initialised to -1, we invert the
700 : * sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and
701 : * __ClearPageFoo *sets* the bit used for PageFoo. We reserve a few high and
702 : * low bits so that an underflow or overflow of page_mapcount() won't be
703 : * mistaken for a page type value.
704 : */
705 :
706 : #define PAGE_TYPE_BASE 0xf0000000
707 : /* Reserve 0x0000007f to catch underflows of page_mapcount */
708 : #define PAGE_MAPCOUNT_RESERVE -128
709 : #define PG_buddy 0x00000080
710 : #define PG_offline 0x00000100
711 : #define PG_table 0x00000200
712 : #define PG_guard 0x00000400
713 :
714 : #define PageType(page, flag) \
715 : ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
716 :
717 0 : static inline int page_has_type(struct page *page)
718 : {
719 0 : return (int)page->page_type < PAGE_MAPCOUNT_RESERVE;
720 : }
721 :
722 : #define PAGE_TYPE_OPS(uname, lname) \
723 : static __always_inline int Page##uname(struct page *page) \
724 : { \
725 : return PageType(page, PG_##lname); \
726 : } \
727 : static __always_inline void __SetPage##uname(struct page *page) \
728 : { \
729 : VM_BUG_ON_PAGE(!PageType(page, 0), page); \
730 : page->page_type &= ~PG_##lname; \
731 : } \
732 : static __always_inline void __ClearPage##uname(struct page *page) \
733 : { \
734 : VM_BUG_ON_PAGE(!Page##uname(page), page); \
735 : page->page_type |= PG_##lname; \
736 : }
737 :
738 : /*
739 : * PageBuddy() indicates that the page is free and in the buddy system
740 : * (see mm/page_alloc.c).
741 : */
742 283243 : PAGE_TYPE_OPS(Buddy, buddy)
743 :
744 : /*
745 : * PageOffline() indicates that the page is logically offline although the
746 : * containing section is online. (e.g. inflated in a balloon driver or
747 : * not onlined when onlining the section).
748 : * The content of these pages is effectively stale. Such pages should not
749 : * be touched (read/write/dump/save) except by their owner.
750 : *
751 : * If a driver wants to allow to offline unmovable PageOffline() pages without
752 : * putting them back to the buddy, it can do so via the memory notifier by
753 : * decrementing the reference count in MEM_GOING_OFFLINE and incrementing the
754 : * reference count in MEM_CANCEL_OFFLINE. When offlining, the PageOffline()
755 : * pages (now with a reference count of zero) are treated like free pages,
756 : * allowing the containing memory block to get offlined. A driver that
757 : * relies on this feature is aware that re-onlining the memory block will
758 : * require to re-set the pages PageOffline() and not giving them to the
759 : * buddy via online_page_callback_t.
760 : */
761 0 : PAGE_TYPE_OPS(Offline, offline)
762 :
763 : /*
764 : * Marks pages in use as page tables.
765 : */
766 118699 : PAGE_TYPE_OPS(Table, table)
767 :
768 : /*
769 : * Marks guardpages used with debug_pagealloc.
770 : */
771 : PAGE_TYPE_OPS(Guard, guard)
772 :
773 : extern bool is_free_buddy_page(struct page *page);
774 :
775 0 : __PAGEFLAG(Isolated, isolated, PF_ANY);
776 :
777 : /*
778 : * If network-based swap is enabled, sl*b must keep track of whether pages
779 : * were allocated from pfmemalloc reserves.
780 : */
781 646409 : static inline int PageSlabPfmemalloc(struct page *page)
782 : {
783 1292839 : VM_BUG_ON_PAGE(!PageSlab(page), page);
784 646430 : return PageActive(page);
785 : }
786 :
787 0 : static inline void SetPageSlabPfmemalloc(struct page *page)
788 : {
789 0 : VM_BUG_ON_PAGE(!PageSlab(page), page);
790 0 : SetPageActive(page);
791 0 : }
792 :
793 17351 : static inline void __ClearPageSlabPfmemalloc(struct page *page)
794 : {
795 34702 : VM_BUG_ON_PAGE(!PageSlab(page), page);
796 17351 : __ClearPageActive(page);
797 17351 : }
798 :
799 : static inline void ClearPageSlabPfmemalloc(struct page *page)
800 : {
801 : VM_BUG_ON_PAGE(!PageSlab(page), page);
802 : ClearPageActive(page);
803 : }
804 :
805 : #ifdef CONFIG_MMU
806 : #define __PG_MLOCKED (1UL << PG_mlocked)
807 : #else
808 : #define __PG_MLOCKED 0
809 : #endif
810 :
811 : /*
812 : * Flags checked when a page is freed. Pages being freed should not have
813 : * these flags set. If they are, there is a problem.
814 : */
815 : #define PAGE_FLAGS_CHECK_AT_FREE \
816 : (1UL << PG_lru | 1UL << PG_locked | \
817 : 1UL << PG_private | 1UL << PG_private_2 | \
818 : 1UL << PG_writeback | 1UL << PG_reserved | \
819 : 1UL << PG_slab | 1UL << PG_active | \
820 : 1UL << PG_unevictable | __PG_MLOCKED)
821 :
822 : /*
823 : * Flags checked when a page is prepped for return by the page allocator.
824 : * Pages being prepped should not have these flags set. If they are set,
825 : * there has been a kernel bug or struct page corruption.
826 : *
827 : * __PG_HWPOISON is exceptional because it needs to be kept beyond page's
828 : * alloc-free cycle to prevent from reusing the page.
829 : */
830 : #define PAGE_FLAGS_CHECK_AT_PREP \
831 : (((1UL << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON)
832 :
833 : #define PAGE_FLAGS_PRIVATE \
834 : (1UL << PG_private | 1UL << PG_private_2)
835 : /**
836 : * page_has_private - Determine if page has private stuff
837 : * @page: The page to be checked
838 : *
839 : * Determine if a page has private stuff, indicating that release routines
840 : * should be invoked upon it.
841 : */
842 1981 : static inline int page_has_private(struct page *page)
843 : {
844 1981 : return !!(page->flags & PAGE_FLAGS_PRIVATE);
845 : }
846 :
847 : #undef PF_ANY
848 : #undef PF_HEAD
849 : #undef PF_ONLY_HEAD
850 : #undef PF_NO_TAIL
851 : #undef PF_NO_COMPOUND
852 : #undef PF_SECOND
853 : #endif /* !__GENERATING_BOUNDS_H */
854 :
855 : #endif /* PAGE_FLAGS_H */
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