Branch data 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_uptodate tells whether the page's contents is valid. When a read
67 : : * completes, the page becomes uptodate, unless a disk I/O error happened.
68 : : *
69 : : * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
70 : : * file-backed pagecache (see mm/vmscan.c).
71 : : *
72 : : * PG_error is set to indicate that an I/O error occurred on this page.
73 : : *
74 : : * PG_arch_1 is an architecture specific page state bit. The generic code
75 : : * guarantees that this bit is cleared for a page when it first is entered into
76 : : * the page cache.
77 : : *
78 : : * PG_hwpoison indicates that a page got corrupted in hardware and contains
79 : : * data with incorrect ECC bits that triggered a machine check. Accessing is
80 : : * not safe since it may cause another machine check. Don't touch!
81 : : */
82 : :
83 : : /*
84 : : * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
85 : : * locked- and dirty-page accounting.
86 : : *
87 : : * The page flags field is split into two parts, the main flags area
88 : : * which extends from the low bits upwards, and the fields area which
89 : : * extends from the high bits downwards.
90 : : *
91 : : * | FIELD | ... | FLAGS |
92 : : * N-1 ^ 0
93 : : * (NR_PAGEFLAGS)
94 : : *
95 : : * The fields area is reserved for fields mapping zone, node (for NUMA) and
96 : : * SPARSEMEM section (for variants of SPARSEMEM that require section ids like
97 : : * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
98 : : */
99 : : enum pageflags {
100 : : PG_locked, /* Page is locked. Don't touch. */
101 : : PG_referenced,
102 : : PG_uptodate,
103 : : PG_dirty,
104 : : PG_lru,
105 : : PG_active,
106 : : PG_workingset,
107 : : PG_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
108 : : PG_error,
109 : : PG_slab,
110 : : PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
111 : : PG_arch_1,
112 : : PG_reserved,
113 : : PG_private, /* If pagecache, has fs-private data */
114 : : PG_private_2, /* If pagecache, has fs aux data */
115 : : PG_writeback, /* Page is under writeback */
116 : : PG_head, /* A head page */
117 : : PG_mappedtodisk, /* Has blocks allocated on-disk */
118 : : PG_reclaim, /* To be reclaimed asap */
119 : : PG_swapbacked, /* Page is backed by RAM/swap */
120 : : PG_unevictable, /* Page is "unevictable" */
121 : : #ifdef CONFIG_MMU
122 : : PG_mlocked, /* Page is vma mlocked */
123 : : #endif
124 : : #ifdef CONFIG_ARCH_USES_PG_UNCACHED
125 : : PG_uncached, /* Page has been mapped as uncached */
126 : : #endif
127 : : #ifdef CONFIG_MEMORY_FAILURE
128 : : PG_hwpoison, /* hardware poisoned page. Don't touch */
129 : : #endif
130 : : #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
131 : : PG_young,
132 : : PG_idle,
133 : : #endif
134 : : __NR_PAGEFLAGS,
135 : :
136 : : /* Filesystems */
137 : : PG_checked = PG_owner_priv_1,
138 : :
139 : : /* SwapBacked */
140 : : PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */
141 : :
142 : : /* Two page bits are conscripted by FS-Cache to maintain local caching
143 : : * state. These bits are set on pages belonging to the netfs's inodes
144 : : * when those inodes are being locally cached.
145 : : */
146 : : PG_fscache = PG_private_2, /* page backed by cache */
147 : :
148 : : /* XEN */
149 : : /* Pinned in Xen as a read-only pagetable page. */
150 : : PG_pinned = PG_owner_priv_1,
151 : : /* Pinned as part of domain save (see xen_mm_pin_all()). */
152 : : PG_savepinned = PG_dirty,
153 : : /* Has a grant mapping of another (foreign) domain's page. */
154 : : PG_foreign = PG_owner_priv_1,
155 : : /* Remapped by swiotlb-xen. */
156 : : PG_xen_remapped = PG_owner_priv_1,
157 : :
158 : : /* SLOB */
159 : : PG_slob_free = PG_private,
160 : :
161 : : /* Compound pages. Stored in first tail page's flags */
162 : : PG_double_map = PG_private_2,
163 : :
164 : : /* non-lru isolated movable page */
165 : : PG_isolated = PG_reclaim,
166 : : };
167 : :
168 : : #ifndef __GENERATING_BOUNDS_H
169 : :
170 : : struct page; /* forward declaration */
171 : :
172 : 3 : static inline struct page *compound_head(struct page *page)
173 : : {
174 : : unsigned long head = READ_ONCE(page->compound_head);
175 : :
176 : 3 : if (unlikely(head & 1))
177 : 3 : return (struct page *) (head - 1);
178 : : return page;
179 : : }
180 : :
181 : : static __always_inline int PageTail(struct page *page)
182 : : {
183 : 3 : return READ_ONCE(page->compound_head) & 1;
184 : : }
185 : :
186 : : static __always_inline int PageCompound(struct page *page)
187 : : {
188 : 3 : return test_bit(PG_head, &page->flags) || PageTail(page);
189 : : }
190 : :
191 : : #define PAGE_POISON_PATTERN -1l
192 : : static inline int PagePoisoned(const struct page *page)
193 : : {
194 : 0 : return page->flags == PAGE_POISON_PATTERN;
195 : : }
196 : :
197 : : #ifdef CONFIG_DEBUG_VM
198 : : void page_init_poison(struct page *page, size_t size);
199 : : #else
200 : : static inline void page_init_poison(struct page *page, size_t size)
201 : : {
202 : : }
203 : : #endif
204 : :
205 : : /*
206 : : * Page flags policies wrt compound pages
207 : : *
208 : : * PF_POISONED_CHECK
209 : : * check if this struct page poisoned/uninitialized
210 : : *
211 : : * PF_ANY:
212 : : * the page flag is relevant for small, head and tail pages.
213 : : *
214 : : * PF_HEAD:
215 : : * for compound page all operations related to the page flag applied to
216 : : * head page.
217 : : *
218 : : * PF_ONLY_HEAD:
219 : : * for compound page, callers only ever operate on the head page.
220 : : *
221 : : * PF_NO_TAIL:
222 : : * modifications of the page flag must be done on small or head pages,
223 : : * checks can be done on tail pages too.
224 : : *
225 : : * PF_NO_COMPOUND:
226 : : * the page flag is not relevant for compound pages.
227 : : */
228 : : #define PF_POISONED_CHECK(page) ({ \
229 : : VM_BUG_ON_PGFLAGS(PagePoisoned(page), page); \
230 : : page; })
231 : : #define PF_ANY(page, enforce) PF_POISONED_CHECK(page)
232 : : #define PF_HEAD(page, enforce) PF_POISONED_CHECK(compound_head(page))
233 : : #define PF_ONLY_HEAD(page, enforce) ({ \
234 : : VM_BUG_ON_PGFLAGS(PageTail(page), page); \
235 : : PF_POISONED_CHECK(page); })
236 : : #define PF_NO_TAIL(page, enforce) ({ \
237 : : VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
238 : : PF_POISONED_CHECK(compound_head(page)); })
239 : : #define PF_NO_COMPOUND(page, enforce) ({ \
240 : : VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
241 : : PF_POISONED_CHECK(page); })
242 : :
243 : : /*
244 : : * Macros to create function definitions for page flags
245 : : */
246 : : #define TESTPAGEFLAG(uname, lname, policy) \
247 : : static __always_inline int Page##uname(struct page *page) \
248 : : { return test_bit(PG_##lname, &policy(page, 0)->flags); }
249 : :
250 : : #define SETPAGEFLAG(uname, lname, policy) \
251 : : static __always_inline void SetPage##uname(struct page *page) \
252 : : { set_bit(PG_##lname, &policy(page, 1)->flags); }
253 : :
254 : : #define CLEARPAGEFLAG(uname, lname, policy) \
255 : : static __always_inline void ClearPage##uname(struct page *page) \
256 : : { clear_bit(PG_##lname, &policy(page, 1)->flags); }
257 : :
258 : : #define __SETPAGEFLAG(uname, lname, policy) \
259 : : static __always_inline void __SetPage##uname(struct page *page) \
260 : : { __set_bit(PG_##lname, &policy(page, 1)->flags); }
261 : :
262 : : #define __CLEARPAGEFLAG(uname, lname, policy) \
263 : : static __always_inline void __ClearPage##uname(struct page *page) \
264 : : { __clear_bit(PG_##lname, &policy(page, 1)->flags); }
265 : :
266 : : #define TESTSETFLAG(uname, lname, policy) \
267 : : static __always_inline int TestSetPage##uname(struct page *page) \
268 : : { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
269 : :
270 : : #define TESTCLEARFLAG(uname, lname, policy) \
271 : : static __always_inline int TestClearPage##uname(struct page *page) \
272 : : { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
273 : :
274 : : #define PAGEFLAG(uname, lname, policy) \
275 : : TESTPAGEFLAG(uname, lname, policy) \
276 : : SETPAGEFLAG(uname, lname, policy) \
277 : : CLEARPAGEFLAG(uname, lname, policy)
278 : :
279 : : #define __PAGEFLAG(uname, lname, policy) \
280 : : TESTPAGEFLAG(uname, lname, policy) \
281 : : __SETPAGEFLAG(uname, lname, policy) \
282 : : __CLEARPAGEFLAG(uname, lname, policy)
283 : :
284 : : #define TESTSCFLAG(uname, lname, policy) \
285 : : TESTSETFLAG(uname, lname, policy) \
286 : : TESTCLEARFLAG(uname, lname, policy)
287 : :
288 : : #define TESTPAGEFLAG_FALSE(uname) \
289 : : static inline int Page##uname(const struct page *page) { return 0; }
290 : :
291 : : #define SETPAGEFLAG_NOOP(uname) \
292 : : static inline void SetPage##uname(struct page *page) { }
293 : :
294 : : #define CLEARPAGEFLAG_NOOP(uname) \
295 : : static inline void ClearPage##uname(struct page *page) { }
296 : :
297 : : #define __CLEARPAGEFLAG_NOOP(uname) \
298 : : static inline void __ClearPage##uname(struct page *page) { }
299 : :
300 : : #define TESTSETFLAG_FALSE(uname) \
301 : : static inline int TestSetPage##uname(struct page *page) { return 0; }
302 : :
303 : : #define TESTCLEARFLAG_FALSE(uname) \
304 : : static inline int TestClearPage##uname(struct page *page) { return 0; }
305 : :
306 : : #define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \
307 : : SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname)
308 : :
309 : : #define TESTSCFLAG_FALSE(uname) \
310 : : TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
311 : :
312 : 3 : __PAGEFLAG(Locked, locked, PF_NO_TAIL)
313 : 3 : PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) __CLEARPAGEFLAG(Waiters, waiters, PF_ONLY_HEAD)
314 : 3 : PAGEFLAG(Error, error, PF_NO_TAIL) TESTCLEARFLAG(Error, error, PF_NO_TAIL)
315 : 3 : PAGEFLAG(Referenced, referenced, PF_HEAD)
316 : 0 : TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
317 : 3 : __SETPAGEFLAG(Referenced, referenced, PF_HEAD)
318 : 3 : PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
319 : : __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
320 : 3 : PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
321 : 3 : PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
322 : 0 : TESTCLEARFLAG(Active, active, PF_HEAD)
323 : 3 : PAGEFLAG(Workingset, workingset, PF_HEAD)
324 : : TESTCLEARFLAG(Workingset, workingset, PF_HEAD)
325 : 3 : __PAGEFLAG(Slab, slab, PF_NO_TAIL)
326 : : __PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
327 : 3 : PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */
328 : :
329 : : /* Xen */
330 : : PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
331 : : TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)
332 : : PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
333 : : PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
334 : : PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
335 : : TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
336 : :
337 : 3 : PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
338 : 3 : __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
339 : 3 : __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
340 : 3 : PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
341 : : __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
342 : 3 : __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
343 : :
344 : : /*
345 : : * Private page markings that may be used by the filesystem that owns the page
346 : : * for its own purposes.
347 : : * - PG_private and PG_private_2 cause releasepage() and co to be invoked
348 : : */
349 : 3 : PAGEFLAG(Private, private, PF_ANY) __SETPAGEFLAG(Private, private, PF_ANY)
350 : : __CLEARPAGEFLAG(Private, private, PF_ANY)
351 : 0 : PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY)
352 : : PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
353 : : TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
354 : :
355 : : /*
356 : : * Only test-and-set exist for PG_writeback. The unconditional operators are
357 : : * risky: they bypass page accounting.
358 : : */
359 : 3 : TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL)
360 : 3 : TESTSCFLAG(Writeback, writeback, PF_NO_TAIL)
361 : 3 : PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL)
362 : :
363 : : /* PG_readahead is only used for reads; PG_reclaim is only for writes */
364 : 3 : PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL)
365 : : TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL)
366 : 3 : PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND)
367 : 0 : TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND)
368 : :
369 : : #ifdef CONFIG_HIGHMEM
370 : : /*
371 : : * Must use a macro here due to header dependency issues. page_zone() is not
372 : : * available at this point.
373 : : */
374 : : #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
375 : : #else
376 : : PAGEFLAG_FALSE(HighMem)
377 : : #endif
378 : :
379 : : #ifdef CONFIG_SWAP
380 : : static __always_inline int PageSwapCache(struct page *page)
381 : : {
382 : : #ifdef CONFIG_THP_SWAP
383 : : page = compound_head(page);
384 : : #endif
385 : 3 : return PageSwapBacked(page) && test_bit(PG_swapcache, &page->flags);
386 : :
387 : : }
388 : 0 : SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
389 : 0 : CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
390 : : #else
391 : : PAGEFLAG_FALSE(SwapCache)
392 : : #endif
393 : :
394 : 3 : PAGEFLAG(Unevictable, unevictable, PF_HEAD)
395 : 0 : __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD)
396 : 3 : TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD)
397 : :
398 : : #ifdef CONFIG_MMU
399 : 3 : PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
400 : : __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
401 : 3 : TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL)
402 : : #else
403 : : PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked)
404 : : TESTSCFLAG_FALSE(Mlocked)
405 : : #endif
406 : :
407 : : #ifdef CONFIG_ARCH_USES_PG_UNCACHED
408 : : PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND)
409 : : #else
410 : : PAGEFLAG_FALSE(Uncached)
411 : : #endif
412 : :
413 : : #ifdef CONFIG_MEMORY_FAILURE
414 : : PAGEFLAG(HWPoison, hwpoison, PF_ANY)
415 : : TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
416 : : #define __PG_HWPOISON (1UL << PG_hwpoison)
417 : : extern bool set_hwpoison_free_buddy_page(struct page *page);
418 : : #else
419 : : PAGEFLAG_FALSE(HWPoison)
420 : : static inline bool set_hwpoison_free_buddy_page(struct page *page)
421 : : {
422 : : return 0;
423 : : }
424 : : #define __PG_HWPOISON 0
425 : : #endif
426 : :
427 : : #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
428 : : TESTPAGEFLAG(Young, young, PF_ANY)
429 : : SETPAGEFLAG(Young, young, PF_ANY)
430 : : TESTCLEARFLAG(Young, young, PF_ANY)
431 : : PAGEFLAG(Idle, idle, PF_ANY)
432 : : #endif
433 : :
434 : : /*
435 : : * On an anonymous page mapped into a user virtual memory area,
436 : : * page->mapping points to its anon_vma, not to a struct address_space;
437 : : * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h.
438 : : *
439 : : * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
440 : : * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON
441 : : * bit; and then page->mapping points, not to an anon_vma, but to a private
442 : : * structure which KSM associates with that merged page. See ksm.h.
443 : : *
444 : : * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable
445 : : * page and then page->mapping points a struct address_space.
446 : : *
447 : : * Please note that, confusingly, "page_mapping" refers to the inode
448 : : * address_space which maps the page from disk; whereas "page_mapped"
449 : : * refers to user virtual address space into which the page is mapped.
450 : : */
451 : : #define PAGE_MAPPING_ANON 0x1
452 : : #define PAGE_MAPPING_MOVABLE 0x2
453 : : #define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
454 : : #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
455 : :
456 : : static __always_inline int PageMappingFlags(struct page *page)
457 : : {
458 : 3 : return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0;
459 : : }
460 : :
461 : : static __always_inline int PageAnon(struct page *page)
462 : : {
463 : 3 : page = compound_head(page);
464 : 3 : return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
465 : : }
466 : :
467 : : static __always_inline int __PageMovable(struct page *page)
468 : : {
469 : 0 : return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
470 : : PAGE_MAPPING_MOVABLE;
471 : : }
472 : :
473 : : #ifdef CONFIG_KSM
474 : : /*
475 : : * A KSM page is one of those write-protected "shared pages" or "merged pages"
476 : : * which KSM maps into multiple mms, wherever identical anonymous page content
477 : : * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any
478 : : * anon_vma, but to that page's node of the stable tree.
479 : : */
480 : : static __always_inline int PageKsm(struct page *page)
481 : : {
482 : : page = compound_head(page);
483 : : return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
484 : : PAGE_MAPPING_KSM;
485 : : }
486 : : #else
487 : : TESTPAGEFLAG_FALSE(Ksm)
488 : : #endif
489 : :
490 : : u64 stable_page_flags(struct page *page);
491 : :
492 : : static inline int PageUptodate(struct page *page)
493 : : {
494 : : int ret;
495 : : page = compound_head(page);
496 : : ret = test_bit(PG_uptodate, &(page)->flags);
497 : : /*
498 : : * Must ensure that the data we read out of the page is loaded
499 : : * _after_ we've loaded page->flags to check for PageUptodate.
500 : : * We can skip the barrier if the page is not uptodate, because
501 : : * we wouldn't be reading anything from it.
502 : : *
503 : : * See SetPageUptodate() for the other side of the story.
504 : : */
505 : 3 : if (ret)
506 : 3 : smp_rmb();
507 : :
508 : : return ret;
509 : : }
510 : :
511 : : static __always_inline void __SetPageUptodate(struct page *page)
512 : : {
513 : : VM_BUG_ON_PAGE(PageTail(page), page);
514 : 3 : smp_wmb();
515 : 3 : __set_bit(PG_uptodate, &page->flags);
516 : : }
517 : :
518 : : static __always_inline void SetPageUptodate(struct page *page)
519 : : {
520 : : VM_BUG_ON_PAGE(PageTail(page), page);
521 : : /*
522 : : * Memory barrier must be issued before setting the PG_uptodate bit,
523 : : * so that all previous stores issued in order to bring the page
524 : : * uptodate are actually visible before PageUptodate becomes true.
525 : : */
526 : 3 : smp_wmb();
527 : 3 : set_bit(PG_uptodate, &page->flags);
528 : : }
529 : :
530 : 3 : CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)
531 : :
532 : : int test_clear_page_writeback(struct page *page);
533 : : int __test_set_page_writeback(struct page *page, bool keep_write);
534 : :
535 : : #define test_set_page_writeback(page) \
536 : : __test_set_page_writeback(page, false)
537 : : #define test_set_page_writeback_keepwrite(page) \
538 : : __test_set_page_writeback(page, true)
539 : :
540 : : static inline void set_page_writeback(struct page *page)
541 : : {
542 : 3 : test_set_page_writeback(page);
543 : : }
544 : :
545 : : static inline void set_page_writeback_keepwrite(struct page *page)
546 : : {
547 : 0 : test_set_page_writeback_keepwrite(page);
548 : : }
549 : :
550 : 3 : __PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY)
551 : :
552 : : static __always_inline void set_compound_head(struct page *page, struct page *head)
553 : : {
554 : 3 : WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
555 : : }
556 : :
557 : : static __always_inline void clear_compound_head(struct page *page)
558 : : {
559 : : WRITE_ONCE(page->compound_head, 0);
560 : : }
561 : :
562 : : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
563 : : static inline void ClearPageCompound(struct page *page)
564 : : {
565 : : BUG_ON(!PageHead(page));
566 : : ClearPageHead(page);
567 : : }
568 : : #endif
569 : :
570 : : #define PG_head_mask ((1UL << PG_head))
571 : :
572 : : #ifdef CONFIG_HUGETLB_PAGE
573 : : int PageHuge(struct page *page);
574 : : int PageHeadHuge(struct page *page);
575 : : bool page_huge_active(struct page *page);
576 : : #else
577 : : TESTPAGEFLAG_FALSE(Huge)
578 : : TESTPAGEFLAG_FALSE(HeadHuge)
579 : :
580 : : static inline bool page_huge_active(struct page *page)
581 : : {
582 : : return 0;
583 : : }
584 : : #endif
585 : :
586 : :
587 : : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
588 : : /*
589 : : * PageHuge() only returns true for hugetlbfs pages, but not for
590 : : * normal or transparent huge pages.
591 : : *
592 : : * PageTransHuge() returns true for both transparent huge and
593 : : * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
594 : : * called only in the core VM paths where hugetlbfs pages can't exist.
595 : : */
596 : : static inline int PageTransHuge(struct page *page)
597 : : {
598 : : VM_BUG_ON_PAGE(PageTail(page), page);
599 : : return PageHead(page);
600 : : }
601 : :
602 : : /*
603 : : * PageTransCompound returns true for both transparent huge pages
604 : : * and hugetlbfs pages, so it should only be called when it's known
605 : : * that hugetlbfs pages aren't involved.
606 : : */
607 : : static inline int PageTransCompound(struct page *page)
608 : : {
609 : : return PageCompound(page);
610 : : }
611 : :
612 : : /*
613 : : * PageTransCompoundMap is the same as PageTransCompound, but it also
614 : : * guarantees the primary MMU has the entire compound page mapped
615 : : * through pmd_trans_huge, which in turn guarantees the secondary MMUs
616 : : * can also map the entire compound page. This allows the secondary
617 : : * MMUs to call get_user_pages() only once for each compound page and
618 : : * to immediately map the entire compound page with a single secondary
619 : : * MMU fault. If there will be a pmd split later, the secondary MMUs
620 : : * will get an update through the MMU notifier invalidation through
621 : : * split_huge_pmd().
622 : : *
623 : : * Unlike PageTransCompound, this is safe to be called only while
624 : : * split_huge_pmd() cannot run from under us, like if protected by the
625 : : * MMU notifier, otherwise it may result in page->_mapcount check false
626 : : * positives.
627 : : *
628 : : * We have to treat page cache THP differently since every subpage of it
629 : : * would get _mapcount inc'ed once it is PMD mapped. But, it may be PTE
630 : : * mapped in the current process so comparing subpage's _mapcount to
631 : : * compound_mapcount to filter out PTE mapped case.
632 : : */
633 : : static inline int PageTransCompoundMap(struct page *page)
634 : : {
635 : : struct page *head;
636 : :
637 : : if (!PageTransCompound(page))
638 : : return 0;
639 : :
640 : : if (PageAnon(page))
641 : : return atomic_read(&page->_mapcount) < 0;
642 : :
643 : : head = compound_head(page);
644 : : /* File THP is PMD mapped and not PTE mapped */
645 : : return atomic_read(&page->_mapcount) ==
646 : : atomic_read(compound_mapcount_ptr(head));
647 : : }
648 : :
649 : : /*
650 : : * PageTransTail returns true for both transparent huge pages
651 : : * and hugetlbfs pages, so it should only be called when it's known
652 : : * that hugetlbfs pages aren't involved.
653 : : */
654 : : static inline int PageTransTail(struct page *page)
655 : : {
656 : : return PageTail(page);
657 : : }
658 : :
659 : : /*
660 : : * PageDoubleMap indicates that the compound page is mapped with PTEs as well
661 : : * as PMDs.
662 : : *
663 : : * This is required for optimization of rmap operations for THP: we can postpone
664 : : * per small page mapcount accounting (and its overhead from atomic operations)
665 : : * until the first PMD split.
666 : : *
667 : : * For the page PageDoubleMap means ->_mapcount in all sub-pages is offset up
668 : : * by one. This reference will go away with last compound_mapcount.
669 : : *
670 : : * See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap().
671 : : */
672 : : static inline int PageDoubleMap(struct page *page)
673 : : {
674 : : return PageHead(page) && test_bit(PG_double_map, &page[1].flags);
675 : : }
676 : :
677 : : static inline void SetPageDoubleMap(struct page *page)
678 : : {
679 : : VM_BUG_ON_PAGE(!PageHead(page), page);
680 : : set_bit(PG_double_map, &page[1].flags);
681 : : }
682 : :
683 : : static inline void ClearPageDoubleMap(struct page *page)
684 : : {
685 : : VM_BUG_ON_PAGE(!PageHead(page), page);
686 : : clear_bit(PG_double_map, &page[1].flags);
687 : : }
688 : : static inline int TestSetPageDoubleMap(struct page *page)
689 : : {
690 : : VM_BUG_ON_PAGE(!PageHead(page), page);
691 : : return test_and_set_bit(PG_double_map, &page[1].flags);
692 : : }
693 : :
694 : : static inline int TestClearPageDoubleMap(struct page *page)
695 : : {
696 : : VM_BUG_ON_PAGE(!PageHead(page), page);
697 : : return test_and_clear_bit(PG_double_map, &page[1].flags);
698 : : }
699 : :
700 : : #else
701 : : TESTPAGEFLAG_FALSE(TransHuge)
702 : : TESTPAGEFLAG_FALSE(TransCompound)
703 : : TESTPAGEFLAG_FALSE(TransCompoundMap)
704 : : TESTPAGEFLAG_FALSE(TransTail)
705 : : PAGEFLAG_FALSE(DoubleMap)
706 : : TESTSETFLAG_FALSE(DoubleMap)
707 : : TESTCLEARFLAG_FALSE(DoubleMap)
708 : : #endif
709 : :
710 : : /*
711 : : * For pages that are never mapped to userspace (and aren't PageSlab),
712 : : * page_type may be used. Because it is initialised to -1, we invert the
713 : : * sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and
714 : : * __ClearPageFoo *sets* the bit used for PageFoo. We reserve a few high and
715 : : * low bits so that an underflow or overflow of page_mapcount() won't be
716 : : * mistaken for a page type value.
717 : : */
718 : :
719 : : #define PAGE_TYPE_BASE 0xf0000000
720 : : /* Reserve 0x0000007f to catch underflows of page_mapcount */
721 : : #define PAGE_MAPCOUNT_RESERVE -128
722 : : #define PG_buddy 0x00000080
723 : : #define PG_offline 0x00000100
724 : : #define PG_kmemcg 0x00000200
725 : : #define PG_table 0x00000400
726 : : #define PG_guard 0x00000800
727 : :
728 : : #define PageType(page, flag) \
729 : : ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
730 : :
731 : : static inline int page_has_type(struct page *page)
732 : : {
733 : 0 : return (int)page->page_type < PAGE_MAPCOUNT_RESERVE;
734 : : }
735 : :
736 : : #define PAGE_TYPE_OPS(uname, lname) \
737 : : static __always_inline int Page##uname(struct page *page) \
738 : : { \
739 : : return PageType(page, PG_##lname); \
740 : : } \
741 : : static __always_inline void __SetPage##uname(struct page *page) \
742 : : { \
743 : : VM_BUG_ON_PAGE(!PageType(page, 0), page); \
744 : : page->page_type &= ~PG_##lname; \
745 : : } \
746 : : static __always_inline void __ClearPage##uname(struct page *page) \
747 : : { \
748 : : VM_BUG_ON_PAGE(!Page##uname(page), page); \
749 : : page->page_type |= PG_##lname; \
750 : : }
751 : :
752 : : /*
753 : : * PageBuddy() indicates that the page is free and in the buddy system
754 : : * (see mm/page_alloc.c).
755 : : */
756 : 3 : PAGE_TYPE_OPS(Buddy, buddy)
757 : :
758 : : /*
759 : : * PageOffline() indicates that the page is logically offline although the
760 : : * containing section is online. (e.g. inflated in a balloon driver or
761 : : * not onlined when onlining the section).
762 : : * The content of these pages is effectively stale. Such pages should not
763 : : * be touched (read/write/dump/save) except by their owner.
764 : : */
765 : 0 : PAGE_TYPE_OPS(Offline, offline)
766 : :
767 : : /*
768 : : * If kmemcg is enabled, the buddy allocator will set PageKmemcg() on
769 : : * pages allocated with __GFP_ACCOUNT. It gets cleared on page free.
770 : : */
771 : 0 : PAGE_TYPE_OPS(Kmemcg, kmemcg)
772 : :
773 : : /*
774 : : * Marks pages in use as page tables.
775 : : */
776 : 3 : PAGE_TYPE_OPS(Table, table)
777 : :
778 : : /*
779 : : * Marks guardpages used with debug_pagealloc.
780 : : */
781 : : PAGE_TYPE_OPS(Guard, guard)
782 : :
783 : : extern bool is_free_buddy_page(struct page *page);
784 : :
785 : 0 : __PAGEFLAG(Isolated, isolated, PF_ANY);
786 : :
787 : : /*
788 : : * If network-based swap is enabled, sl*b must keep track of whether pages
789 : : * were allocated from pfmemalloc reserves.
790 : : */
791 : 3 : static inline int PageSlabPfmemalloc(struct page *page)
792 : : {
793 : : VM_BUG_ON_PAGE(!PageSlab(page), page);
794 : 3 : return PageActive(page);
795 : : }
796 : :
797 : 0 : static inline void SetPageSlabPfmemalloc(struct page *page)
798 : : {
799 : : VM_BUG_ON_PAGE(!PageSlab(page), page);
800 : : SetPageActive(page);
801 : 0 : }
802 : :
803 : 3 : static inline void __ClearPageSlabPfmemalloc(struct page *page)
804 : : {
805 : : VM_BUG_ON_PAGE(!PageSlab(page), page);
806 : : __ClearPageActive(page);
807 : 3 : }
808 : :
809 : : static inline void ClearPageSlabPfmemalloc(struct page *page)
810 : : {
811 : : VM_BUG_ON_PAGE(!PageSlab(page), page);
812 : : ClearPageActive(page);
813 : : }
814 : :
815 : : #ifdef CONFIG_MMU
816 : : #define __PG_MLOCKED (1UL << PG_mlocked)
817 : : #else
818 : : #define __PG_MLOCKED 0
819 : : #endif
820 : :
821 : : /*
822 : : * Flags checked when a page is freed. Pages being freed should not have
823 : : * these flags set. It they are, there is a problem.
824 : : */
825 : : #define PAGE_FLAGS_CHECK_AT_FREE \
826 : : (1UL << PG_lru | 1UL << PG_locked | \
827 : : 1UL << PG_private | 1UL << PG_private_2 | \
828 : : 1UL << PG_writeback | 1UL << PG_reserved | \
829 : : 1UL << PG_slab | 1UL << PG_active | \
830 : : 1UL << PG_unevictable | __PG_MLOCKED)
831 : :
832 : : /*
833 : : * Flags checked when a page is prepped for return by the page allocator.
834 : : * Pages being prepped should not have these flags set. It they are set,
835 : : * there has been a kernel bug or struct page corruption.
836 : : *
837 : : * __PG_HWPOISON is exceptional because it needs to be kept beyond page's
838 : : * alloc-free cycle to prevent from reusing the page.
839 : : */
840 : : #define PAGE_FLAGS_CHECK_AT_PREP \
841 : : (((1UL << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON)
842 : :
843 : : #define PAGE_FLAGS_PRIVATE \
844 : : (1UL << PG_private | 1UL << PG_private_2)
845 : : /**
846 : : * page_has_private - Determine if page has private stuff
847 : : * @page: The page to be checked
848 : : *
849 : : * Determine if a page has private stuff, indicating that release routines
850 : : * should be invoked upon it.
851 : : */
852 : : static inline int page_has_private(struct page *page)
853 : : {
854 : 3 : return !!(page->flags & PAGE_FLAGS_PRIVATE);
855 : : }
856 : :
857 : : #undef PF_ANY
858 : : #undef PF_HEAD
859 : : #undef PF_ONLY_HEAD
860 : : #undef PF_NO_TAIL
861 : : #undef PF_NO_COMPOUND
862 : : #endif /* !__GENERATING_BOUNDS_H */
863 : :
864 : : #endif /* PAGE_FLAGS_H */
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