Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Macros for manipulating and testing page->flags | |
3 | */ | |
4 | ||
5 | #ifndef PAGE_FLAGS_H | |
6 | #define PAGE_FLAGS_H | |
7 | ||
f886ed44 | 8 | #include <linux/types.h> |
9223b419 | 9 | #ifndef __GENERATING_BOUNDS_H |
6d777953 | 10 | #include <linux/mm_types.h> |
01fc0ac1 | 11 | #include <generated/bounds.h> |
9223b419 | 12 | #endif /* !__GENERATING_BOUNDS_H */ |
f886ed44 | 13 | |
1da177e4 LT |
14 | /* |
15 | * Various page->flags bits: | |
16 | * | |
17 | * PG_reserved is set for special pages, which can never be swapped out. Some | |
18 | * of them might not even exist (eg empty_bad_page)... | |
19 | * | |
da6052f7 NP |
20 | * The PG_private bitflag is set on pagecache pages if they contain filesystem |
21 | * specific data (which is normally at page->private). It can be used by | |
22 | * private allocations for its own usage. | |
1da177e4 | 23 | * |
da6052f7 NP |
24 | * During initiation of disk I/O, PG_locked is set. This bit is set before I/O |
25 | * and cleared when writeback _starts_ or when read _completes_. PG_writeback | |
26 | * is set before writeback starts and cleared when it finishes. | |
27 | * | |
28 | * PG_locked also pins a page in pagecache, and blocks truncation of the file | |
29 | * while it is held. | |
30 | * | |
31 | * page_waitqueue(page) is a wait queue of all tasks waiting for the page | |
32 | * to become unlocked. | |
1da177e4 LT |
33 | * |
34 | * PG_uptodate tells whether the page's contents is valid. When a read | |
35 | * completes, the page becomes uptodate, unless a disk I/O error happened. | |
36 | * | |
da6052f7 NP |
37 | * PG_referenced, PG_reclaim are used for page reclaim for anonymous and |
38 | * file-backed pagecache (see mm/vmscan.c). | |
1da177e4 LT |
39 | * |
40 | * PG_error is set to indicate that an I/O error occurred on this page. | |
41 | * | |
42 | * PG_arch_1 is an architecture specific page state bit. The generic code | |
43 | * guarantees that this bit is cleared for a page when it first is entered into | |
44 | * the page cache. | |
45 | * | |
46 | * PG_highmem pages are not permanently mapped into the kernel virtual address | |
47 | * space, they need to be kmapped separately for doing IO on the pages. The | |
48 | * struct page (these bits with information) are always mapped into kernel | |
49 | * address space... | |
da6052f7 NP |
50 | * |
51 | * PG_buddy is set to indicate that the page is free and in the buddy system | |
52 | * (see mm/page_alloc.c). | |
53 | * | |
d466f2fc AK |
54 | * PG_hwpoison indicates that a page got corrupted in hardware and contains |
55 | * data with incorrect ECC bits that triggered a machine check. Accessing is | |
56 | * not safe since it may cause another machine check. Don't touch! | |
1da177e4 LT |
57 | */ |
58 | ||
59 | /* | |
60 | * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break | |
91fc8ab3 AW |
61 | * locked- and dirty-page accounting. |
62 | * | |
63 | * The page flags field is split into two parts, the main flags area | |
64 | * which extends from the low bits upwards, and the fields area which | |
65 | * extends from the high bits downwards. | |
66 | * | |
67 | * | FIELD | ... | FLAGS | | |
9223b419 CL |
68 | * N-1 ^ 0 |
69 | * (NR_PAGEFLAGS) | |
91fc8ab3 | 70 | * |
9223b419 CL |
71 | * The fields area is reserved for fields mapping zone, node (for NUMA) and |
72 | * SPARSEMEM section (for variants of SPARSEMEM that require section ids like | |
73 | * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP). | |
1da177e4 | 74 | */ |
e2683181 CL |
75 | enum pageflags { |
76 | PG_locked, /* Page is locked. Don't touch. */ | |
77 | PG_error, | |
78 | PG_referenced, | |
79 | PG_uptodate, | |
80 | PG_dirty, | |
81 | PG_lru, | |
82 | PG_active, | |
83 | PG_slab, | |
84 | PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/ | |
e2683181 CL |
85 | PG_arch_1, |
86 | PG_reserved, | |
87 | PG_private, /* If pagecache, has fs-private data */ | |
266cf658 | 88 | PG_private_2, /* If pagecache, has fs aux data */ |
e2683181 | 89 | PG_writeback, /* Page is under writeback */ |
e20b8cca CL |
90 | #ifdef CONFIG_PAGEFLAGS_EXTENDED |
91 | PG_head, /* A head page */ | |
92 | PG_tail, /* A tail page */ | |
93 | #else | |
e2683181 | 94 | PG_compound, /* A compound page */ |
e20b8cca | 95 | #endif |
e2683181 CL |
96 | PG_swapcache, /* Swap page: swp_entry_t in private */ |
97 | PG_mappedtodisk, /* Has blocks allocated on-disk */ | |
98 | PG_reclaim, /* To be reclaimed asap */ | |
e2683181 | 99 | PG_buddy, /* Page is free, on buddy lists */ |
b2e18538 | 100 | PG_swapbacked, /* Page is backed by RAM/swap */ |
894bc310 | 101 | PG_unevictable, /* Page is "unevictable" */ |
af8e3354 | 102 | #ifdef CONFIG_MMU |
b291f000 | 103 | PG_mlocked, /* Page is vma mlocked */ |
894bc310 | 104 | #endif |
46cf98cd | 105 | #ifdef CONFIG_ARCH_USES_PG_UNCACHED |
602c4d11 | 106 | PG_uncached, /* Page has been mapped as uncached */ |
d466f2fc AK |
107 | #endif |
108 | #ifdef CONFIG_MEMORY_FAILURE | |
109 | PG_hwpoison, /* hardware poisoned page. Don't touch */ | |
f886ed44 | 110 | #endif |
0cad47cf AW |
111 | __NR_PAGEFLAGS, |
112 | ||
113 | /* Filesystems */ | |
114 | PG_checked = PG_owner_priv_1, | |
115 | ||
266cf658 DH |
116 | /* Two page bits are conscripted by FS-Cache to maintain local caching |
117 | * state. These bits are set on pages belonging to the netfs's inodes | |
118 | * when those inodes are being locally cached. | |
119 | */ | |
120 | PG_fscache = PG_private_2, /* page backed by cache */ | |
121 | ||
0cad47cf AW |
122 | /* XEN */ |
123 | PG_pinned = PG_owner_priv_1, | |
124 | PG_savepinned = PG_dirty, | |
8a38082d | 125 | |
9023cb7e | 126 | /* SLOB */ |
9023cb7e AW |
127 | PG_slob_free = PG_private, |
128 | ||
8a38082d AW |
129 | /* SLUB */ |
130 | PG_slub_frozen = PG_active, | |
131 | PG_slub_debug = PG_error, | |
e2683181 | 132 | }; |
1da177e4 | 133 | |
9223b419 CL |
134 | #ifndef __GENERATING_BOUNDS_H |
135 | ||
f94a62e9 CL |
136 | /* |
137 | * Macros to create function definitions for page flags | |
138 | */ | |
139 | #define TESTPAGEFLAG(uname, lname) \ | |
140 | static inline int Page##uname(struct page *page) \ | |
141 | { return test_bit(PG_##lname, &page->flags); } | |
142 | ||
143 | #define SETPAGEFLAG(uname, lname) \ | |
144 | static inline void SetPage##uname(struct page *page) \ | |
145 | { set_bit(PG_##lname, &page->flags); } | |
146 | ||
147 | #define CLEARPAGEFLAG(uname, lname) \ | |
148 | static inline void ClearPage##uname(struct page *page) \ | |
149 | { clear_bit(PG_##lname, &page->flags); } | |
150 | ||
151 | #define __SETPAGEFLAG(uname, lname) \ | |
152 | static inline void __SetPage##uname(struct page *page) \ | |
153 | { __set_bit(PG_##lname, &page->flags); } | |
154 | ||
155 | #define __CLEARPAGEFLAG(uname, lname) \ | |
156 | static inline void __ClearPage##uname(struct page *page) \ | |
157 | { __clear_bit(PG_##lname, &page->flags); } | |
158 | ||
159 | #define TESTSETFLAG(uname, lname) \ | |
160 | static inline int TestSetPage##uname(struct page *page) \ | |
161 | { return test_and_set_bit(PG_##lname, &page->flags); } | |
162 | ||
163 | #define TESTCLEARFLAG(uname, lname) \ | |
164 | static inline int TestClearPage##uname(struct page *page) \ | |
165 | { return test_and_clear_bit(PG_##lname, &page->flags); } | |
166 | ||
451ea25d JW |
167 | #define __TESTCLEARFLAG(uname, lname) \ |
168 | static inline int __TestClearPage##uname(struct page *page) \ | |
169 | { return __test_and_clear_bit(PG_##lname, &page->flags); } | |
f94a62e9 CL |
170 | |
171 | #define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \ | |
172 | SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname) | |
173 | ||
174 | #define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \ | |
175 | __SETPAGEFLAG(uname, lname) __CLEARPAGEFLAG(uname, lname) | |
176 | ||
ec7cade8 CL |
177 | #define PAGEFLAG_FALSE(uname) \ |
178 | static inline int Page##uname(struct page *page) \ | |
179 | { return 0; } | |
180 | ||
f94a62e9 CL |
181 | #define TESTSCFLAG(uname, lname) \ |
182 | TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname) | |
183 | ||
8a7a8544 LS |
184 | #define SETPAGEFLAG_NOOP(uname) \ |
185 | static inline void SetPage##uname(struct page *page) { } | |
186 | ||
187 | #define CLEARPAGEFLAG_NOOP(uname) \ | |
188 | static inline void ClearPage##uname(struct page *page) { } | |
189 | ||
190 | #define __CLEARPAGEFLAG_NOOP(uname) \ | |
191 | static inline void __ClearPage##uname(struct page *page) { } | |
192 | ||
193 | #define TESTCLEARFLAG_FALSE(uname) \ | |
194 | static inline int TestClearPage##uname(struct page *page) { return 0; } | |
195 | ||
451ea25d JW |
196 | #define __TESTCLEARFLAG_FALSE(uname) \ |
197 | static inline int __TestClearPage##uname(struct page *page) { return 0; } | |
198 | ||
6a1e7f77 CL |
199 | struct page; /* forward declaration */ |
200 | ||
03fb3d2a | 201 | TESTPAGEFLAG(Locked, locked) TESTSETFLAG(Locked, locked) |
6a1e7f77 CL |
202 | PAGEFLAG(Error, error) |
203 | PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced) | |
204 | PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty) | |
205 | PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru) | |
206 | PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active) | |
894bc310 | 207 | TESTCLEARFLAG(Active, active) |
6a1e7f77 | 208 | __PAGEFLAG(Slab, slab) |
0cad47cf AW |
209 | PAGEFLAG(Checked, checked) /* Used by some filesystems */ |
210 | PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */ | |
211 | PAGEFLAG(SavePinned, savepinned); /* Xen */ | |
6a1e7f77 | 212 | PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved) |
b2e18538 | 213 | PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked) |
6a1e7f77 | 214 | |
9023cb7e AW |
215 | __PAGEFLAG(SlobFree, slob_free) |
216 | ||
8a38082d AW |
217 | __PAGEFLAG(SlubFrozen, slub_frozen) |
218 | __PAGEFLAG(SlubDebug, slub_debug) | |
219 | ||
266cf658 DH |
220 | /* |
221 | * Private page markings that may be used by the filesystem that owns the page | |
222 | * for its own purposes. | |
223 | * - PG_private and PG_private_2 cause releasepage() and co to be invoked | |
224 | */ | |
225 | PAGEFLAG(Private, private) __SETPAGEFLAG(Private, private) | |
226 | __CLEARPAGEFLAG(Private, private) | |
227 | PAGEFLAG(Private2, private_2) TESTSCFLAG(Private2, private_2) | |
228 | PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1) | |
229 | ||
6a1e7f77 CL |
230 | /* |
231 | * Only test-and-set exist for PG_writeback. The unconditional operators are | |
232 | * risky: they bypass page accounting. | |
233 | */ | |
234 | TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback) | |
235 | __PAGEFLAG(Buddy, buddy) | |
236 | PAGEFLAG(MappedToDisk, mappedtodisk) | |
237 | ||
238 | /* PG_readahead is only used for file reads; PG_reclaim is only for writes */ | |
239 | PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim) | |
0a128b2b | 240 | PAGEFLAG(Readahead, reclaim) /* Reminder to do async read-ahead */ |
6a1e7f77 CL |
241 | |
242 | #ifdef CONFIG_HIGHMEM | |
1da177e4 | 243 | /* |
6a1e7f77 CL |
244 | * Must use a macro here due to header dependency issues. page_zone() is not |
245 | * available at this point. | |
1da177e4 | 246 | */ |
0a128b2b | 247 | #define PageHighMem(__p) is_highmem(page_zone(__p)) |
6a1e7f77 | 248 | #else |
ec7cade8 | 249 | PAGEFLAG_FALSE(HighMem) |
6a1e7f77 CL |
250 | #endif |
251 | ||
252 | #ifdef CONFIG_SWAP | |
253 | PAGEFLAG(SwapCache, swapcache) | |
254 | #else | |
ec7cade8 | 255 | PAGEFLAG_FALSE(SwapCache) |
6d91add0 | 256 | SETPAGEFLAG_NOOP(SwapCache) CLEARPAGEFLAG_NOOP(SwapCache) |
6a1e7f77 CL |
257 | #endif |
258 | ||
894bc310 LS |
259 | PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable) |
260 | TESTCLEARFLAG(Unevictable, unevictable) | |
b291f000 | 261 | |
af8e3354 | 262 | #ifdef CONFIG_MMU |
b291f000 | 263 | PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked) |
451ea25d | 264 | TESTSCFLAG(Mlocked, mlocked) __TESTCLEARFLAG(Mlocked, mlocked) |
894bc310 | 265 | #else |
451ea25d JW |
266 | PAGEFLAG_FALSE(Mlocked) SETPAGEFLAG_NOOP(Mlocked) |
267 | TESTCLEARFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked) | |
894bc310 LS |
268 | #endif |
269 | ||
46cf98cd | 270 | #ifdef CONFIG_ARCH_USES_PG_UNCACHED |
6a1e7f77 | 271 | PAGEFLAG(Uncached, uncached) |
602c4d11 | 272 | #else |
ec7cade8 | 273 | PAGEFLAG_FALSE(Uncached) |
6a1e7f77 | 274 | #endif |
1da177e4 | 275 | |
d466f2fc AK |
276 | #ifdef CONFIG_MEMORY_FAILURE |
277 | PAGEFLAG(HWPoison, hwpoison) | |
847ce401 | 278 | TESTSCFLAG(HWPoison, hwpoison) |
d466f2fc AK |
279 | #define __PG_HWPOISON (1UL << PG_hwpoison) |
280 | #else | |
281 | PAGEFLAG_FALSE(HWPoison) | |
282 | #define __PG_HWPOISON 0 | |
283 | #endif | |
284 | ||
1a9b5b7f WF |
285 | u64 stable_page_flags(struct page *page); |
286 | ||
0ed361de NP |
287 | static inline int PageUptodate(struct page *page) |
288 | { | |
289 | int ret = test_bit(PG_uptodate, &(page)->flags); | |
290 | ||
291 | /* | |
292 | * Must ensure that the data we read out of the page is loaded | |
293 | * _after_ we've loaded page->flags to check for PageUptodate. | |
294 | * We can skip the barrier if the page is not uptodate, because | |
295 | * we wouldn't be reading anything from it. | |
296 | * | |
297 | * See SetPageUptodate() for the other side of the story. | |
298 | */ | |
299 | if (ret) | |
300 | smp_rmb(); | |
301 | ||
302 | return ret; | |
303 | } | |
304 | ||
305 | static inline void __SetPageUptodate(struct page *page) | |
306 | { | |
307 | smp_wmb(); | |
308 | __set_bit(PG_uptodate, &(page)->flags); | |
0ed361de NP |
309 | } |
310 | ||
2dcea57a HC |
311 | static inline void SetPageUptodate(struct page *page) |
312 | { | |
0ed361de | 313 | #ifdef CONFIG_S390 |
2dcea57a | 314 | if (!test_and_set_bit(PG_uptodate, &page->flags)) |
6c210482 | 315 | page_clear_dirty(page); |
f6ac2354 | 316 | #else |
0ed361de NP |
317 | /* |
318 | * Memory barrier must be issued before setting the PG_uptodate bit, | |
319 | * so that all previous stores issued in order to bring the page | |
320 | * uptodate are actually visible before PageUptodate becomes true. | |
321 | * | |
322 | * s390 doesn't need an explicit smp_wmb here because the test and | |
323 | * set bit already provides full barriers. | |
324 | */ | |
325 | smp_wmb(); | |
326 | set_bit(PG_uptodate, &(page)->flags); | |
1da177e4 | 327 | #endif |
0ed361de NP |
328 | } |
329 | ||
6a1e7f77 | 330 | CLEARPAGEFLAG(Uptodate, uptodate) |
1da177e4 | 331 | |
6a1e7f77 | 332 | extern void cancel_dirty_page(struct page *page, unsigned int account_size); |
d77c2d7c | 333 | |
6a1e7f77 CL |
334 | int test_clear_page_writeback(struct page *page); |
335 | int test_set_page_writeback(struct page *page); | |
1da177e4 | 336 | |
6a1e7f77 CL |
337 | static inline void set_page_writeback(struct page *page) |
338 | { | |
339 | test_set_page_writeback(page); | |
340 | } | |
1da177e4 | 341 | |
e20b8cca CL |
342 | #ifdef CONFIG_PAGEFLAGS_EXTENDED |
343 | /* | |
344 | * System with lots of page flags available. This allows separate | |
345 | * flags for PageHead() and PageTail() checks of compound pages so that bit | |
346 | * tests can be used in performance sensitive paths. PageCompound is | |
347 | * generally not used in hot code paths. | |
348 | */ | |
349 | __PAGEFLAG(Head, head) | |
350 | __PAGEFLAG(Tail, tail) | |
351 | ||
352 | static inline int PageCompound(struct page *page) | |
353 | { | |
354 | return page->flags & ((1L << PG_head) | (1L << PG_tail)); | |
355 | ||
356 | } | |
357 | #else | |
358 | /* | |
359 | * Reduce page flag use as much as possible by overlapping | |
360 | * compound page flags with the flags used for page cache pages. Possible | |
361 | * because PageCompound is always set for compound pages and not for | |
362 | * pages on the LRU and/or pagecache. | |
363 | */ | |
6a1e7f77 CL |
364 | TESTPAGEFLAG(Compound, compound) |
365 | __PAGEFLAG(Head, compound) | |
1da177e4 | 366 | |
d85f3385 | 367 | /* |
6d777953 | 368 | * PG_reclaim is used in combination with PG_compound to mark the |
6a1e7f77 CL |
369 | * head and tail of a compound page. This saves one page flag |
370 | * but makes it impossible to use compound pages for the page cache. | |
371 | * The PG_reclaim bit would have to be used for reclaim or readahead | |
372 | * if compound pages enter the page cache. | |
6d777953 CL |
373 | * |
374 | * PG_compound & PG_reclaim => Tail page | |
375 | * PG_compound & ~PG_reclaim => Head page | |
d85f3385 | 376 | */ |
6d777953 CL |
377 | #define PG_head_tail_mask ((1L << PG_compound) | (1L << PG_reclaim)) |
378 | ||
6a1e7f77 CL |
379 | static inline int PageTail(struct page *page) |
380 | { | |
381 | return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask); | |
382 | } | |
6d777953 CL |
383 | |
384 | static inline void __SetPageTail(struct page *page) | |
385 | { | |
386 | page->flags |= PG_head_tail_mask; | |
387 | } | |
388 | ||
389 | static inline void __ClearPageTail(struct page *page) | |
390 | { | |
391 | page->flags &= ~PG_head_tail_mask; | |
392 | } | |
393 | ||
e20b8cca | 394 | #endif /* !PAGEFLAGS_EXTENDED */ |
dfa7e20c | 395 | |
af8e3354 | 396 | #ifdef CONFIG_MMU |
33925b25 DH |
397 | #define __PG_MLOCKED (1 << PG_mlocked) |
398 | #else | |
b291f000 | 399 | #define __PG_MLOCKED 0 |
894bc310 LS |
400 | #endif |
401 | ||
dfa7e20c RA |
402 | /* |
403 | * Flags checked when a page is freed. Pages being freed should not have | |
404 | * these flags set. It they are, there is a problem. | |
405 | */ | |
79f4b7bf | 406 | #define PAGE_FLAGS_CHECK_AT_FREE \ |
266cf658 DH |
407 | (1 << PG_lru | 1 << PG_locked | \ |
408 | 1 << PG_private | 1 << PG_private_2 | \ | |
409 | 1 << PG_buddy | 1 << PG_writeback | 1 << PG_reserved | \ | |
410 | 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \ | |
d466f2fc | 411 | 1 << PG_unevictable | __PG_MLOCKED | __PG_HWPOISON) |
dfa7e20c RA |
412 | |
413 | /* | |
414 | * Flags checked when a page is prepped for return by the page allocator. | |
79f4b7bf HD |
415 | * Pages being prepped should not have any flags set. It they are set, |
416 | * there has been a kernel bug or struct page corruption. | |
dfa7e20c | 417 | */ |
79f4b7bf | 418 | #define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1) |
dfa7e20c | 419 | |
edcf4748 JW |
420 | #define PAGE_FLAGS_PRIVATE \ |
421 | (1 << PG_private | 1 << PG_private_2) | |
266cf658 DH |
422 | /** |
423 | * page_has_private - Determine if page has private stuff | |
424 | * @page: The page to be checked | |
425 | * | |
426 | * Determine if a page has private stuff, indicating that release routines | |
427 | * should be invoked upon it. | |
428 | */ | |
edcf4748 JW |
429 | static inline int page_has_private(struct page *page) |
430 | { | |
431 | return !!(page->flags & PAGE_FLAGS_PRIVATE); | |
432 | } | |
433 | ||
434 | #endif /* !__GENERATING_BOUNDS_H */ | |
266cf658 | 435 | |
1da177e4 | 436 | #endif /* PAGE_FLAGS_H */ |