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Commit | Line | Data |
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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> |
6d777953 | 9 | #include <linux/mm_types.h> |
f886ed44 | 10 | |
1da177e4 LT |
11 | /* |
12 | * Various page->flags bits: | |
13 | * | |
14 | * PG_reserved is set for special pages, which can never be swapped out. Some | |
15 | * of them might not even exist (eg empty_bad_page)... | |
16 | * | |
da6052f7 NP |
17 | * The PG_private bitflag is set on pagecache pages if they contain filesystem |
18 | * specific data (which is normally at page->private). It can be used by | |
19 | * private allocations for its own usage. | |
1da177e4 | 20 | * |
da6052f7 NP |
21 | * During initiation of disk I/O, PG_locked is set. This bit is set before I/O |
22 | * and cleared when writeback _starts_ or when read _completes_. PG_writeback | |
23 | * is set before writeback starts and cleared when it finishes. | |
24 | * | |
25 | * PG_locked also pins a page in pagecache, and blocks truncation of the file | |
26 | * while it is held. | |
27 | * | |
28 | * page_waitqueue(page) is a wait queue of all tasks waiting for the page | |
29 | * to become unlocked. | |
1da177e4 LT |
30 | * |
31 | * PG_uptodate tells whether the page's contents is valid. When a read | |
32 | * completes, the page becomes uptodate, unless a disk I/O error happened. | |
33 | * | |
da6052f7 NP |
34 | * PG_referenced, PG_reclaim are used for page reclaim for anonymous and |
35 | * file-backed pagecache (see mm/vmscan.c). | |
1da177e4 LT |
36 | * |
37 | * PG_error is set to indicate that an I/O error occurred on this page. | |
38 | * | |
39 | * PG_arch_1 is an architecture specific page state bit. The generic code | |
40 | * guarantees that this bit is cleared for a page when it first is entered into | |
41 | * the page cache. | |
42 | * | |
43 | * PG_highmem pages are not permanently mapped into the kernel virtual address | |
44 | * space, they need to be kmapped separately for doing IO on the pages. The | |
45 | * struct page (these bits with information) are always mapped into kernel | |
46 | * address space... | |
da6052f7 NP |
47 | * |
48 | * PG_buddy is set to indicate that the page is free and in the buddy system | |
49 | * (see mm/page_alloc.c). | |
50 | * | |
1da177e4 LT |
51 | */ |
52 | ||
53 | /* | |
54 | * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break | |
91fc8ab3 AW |
55 | * locked- and dirty-page accounting. |
56 | * | |
57 | * The page flags field is split into two parts, the main flags area | |
58 | * which extends from the low bits upwards, and the fields area which | |
59 | * extends from the high bits downwards. | |
60 | * | |
61 | * | FIELD | ... | FLAGS | | |
62 | * N-1 ^ 0 | |
63 | * (N-FLAGS_RESERVED) | |
64 | * | |
65 | * The fields area is reserved for fields mapping zone, node and SPARSEMEM | |
66 | * section. The boundry between these two areas is defined by | |
67 | * FLAGS_RESERVED which defines the width of the fields section | |
68 | * (see linux/mmzone.h). New flags must _not_ overlap with this area. | |
1da177e4 | 69 | */ |
e2683181 CL |
70 | enum pageflags { |
71 | PG_locked, /* Page is locked. Don't touch. */ | |
72 | PG_error, | |
73 | PG_referenced, | |
74 | PG_uptodate, | |
75 | PG_dirty, | |
76 | PG_lru, | |
77 | PG_active, | |
78 | PG_slab, | |
79 | PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/ | |
80 | PG_checked = PG_owner_priv_1, /* Used by some filesystems */ | |
81 | PG_pinned = PG_owner_priv_1, /* Xen pinned pagetable */ | |
82 | PG_arch_1, | |
83 | PG_reserved, | |
84 | PG_private, /* If pagecache, has fs-private data */ | |
85 | PG_writeback, /* Page is under writeback */ | |
86 | PG_compound, /* A compound page */ | |
87 | PG_swapcache, /* Swap page: swp_entry_t in private */ | |
88 | PG_mappedtodisk, /* Has blocks allocated on-disk */ | |
89 | PG_reclaim, /* To be reclaimed asap */ | |
90 | /* PG_readahead is only used for file reads; PG_reclaim is only for writes */ | |
91 | PG_readahead = PG_reclaim, /* Reminder to do async read-ahead */ | |
92 | PG_buddy, /* Page is free, on buddy lists */ | |
f886ed44 AM |
93 | |
94 | #if (BITS_PER_LONG > 32) | |
95 | /* | |
96 | * 64-bit-only flags build down from bit 31 | |
97 | * | |
98 | * 32 bit -------------------------------| FIELDS | FLAGS | | |
99 | * 64 bit | FIELDS | ?????? FLAGS | | |
100 | * 63 32 0 | |
101 | */ | |
e2683181 | 102 | PG_uncached = 31, /* Page has been mapped as uncached */ |
f886ed44 | 103 | #endif |
e2683181 CL |
104 | NR_PAGEFLAGS |
105 | }; | |
1da177e4 | 106 | |
1da177e4 LT |
107 | /* |
108 | * Manipulation of page state flags | |
109 | */ | |
110 | #define PageLocked(page) \ | |
111 | test_bit(PG_locked, &(page)->flags) | |
112 | #define SetPageLocked(page) \ | |
113 | set_bit(PG_locked, &(page)->flags) | |
114 | #define TestSetPageLocked(page) \ | |
115 | test_and_set_bit(PG_locked, &(page)->flags) | |
116 | #define ClearPageLocked(page) \ | |
117 | clear_bit(PG_locked, &(page)->flags) | |
118 | #define TestClearPageLocked(page) \ | |
119 | test_and_clear_bit(PG_locked, &(page)->flags) | |
120 | ||
121 | #define PageError(page) test_bit(PG_error, &(page)->flags) | |
122 | #define SetPageError(page) set_bit(PG_error, &(page)->flags) | |
123 | #define ClearPageError(page) clear_bit(PG_error, &(page)->flags) | |
124 | ||
125 | #define PageReferenced(page) test_bit(PG_referenced, &(page)->flags) | |
126 | #define SetPageReferenced(page) set_bit(PG_referenced, &(page)->flags) | |
127 | #define ClearPageReferenced(page) clear_bit(PG_referenced, &(page)->flags) | |
128 | #define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags) | |
129 | ||
0ed361de NP |
130 | static inline int PageUptodate(struct page *page) |
131 | { | |
132 | int ret = test_bit(PG_uptodate, &(page)->flags); | |
133 | ||
134 | /* | |
135 | * Must ensure that the data we read out of the page is loaded | |
136 | * _after_ we've loaded page->flags to check for PageUptodate. | |
137 | * We can skip the barrier if the page is not uptodate, because | |
138 | * we wouldn't be reading anything from it. | |
139 | * | |
140 | * See SetPageUptodate() for the other side of the story. | |
141 | */ | |
142 | if (ret) | |
143 | smp_rmb(); | |
144 | ||
145 | return ret; | |
146 | } | |
147 | ||
148 | static inline void __SetPageUptodate(struct page *page) | |
149 | { | |
150 | smp_wmb(); | |
151 | __set_bit(PG_uptodate, &(page)->flags); | |
f6ac2354 | 152 | #ifdef CONFIG_S390 |
0ed361de NP |
153 | page_clear_dirty(page); |
154 | #endif | |
155 | } | |
156 | ||
2dcea57a HC |
157 | static inline void SetPageUptodate(struct page *page) |
158 | { | |
0ed361de | 159 | #ifdef CONFIG_S390 |
2dcea57a | 160 | if (!test_and_set_bit(PG_uptodate, &page->flags)) |
6c210482 | 161 | page_clear_dirty(page); |
f6ac2354 | 162 | #else |
0ed361de NP |
163 | /* |
164 | * Memory barrier must be issued before setting the PG_uptodate bit, | |
165 | * so that all previous stores issued in order to bring the page | |
166 | * uptodate are actually visible before PageUptodate becomes true. | |
167 | * | |
168 | * s390 doesn't need an explicit smp_wmb here because the test and | |
169 | * set bit already provides full barriers. | |
170 | */ | |
171 | smp_wmb(); | |
172 | set_bit(PG_uptodate, &(page)->flags); | |
1da177e4 | 173 | #endif |
0ed361de NP |
174 | } |
175 | ||
1da177e4 LT |
176 | #define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags) |
177 | ||
178 | #define PageDirty(page) test_bit(PG_dirty, &(page)->flags) | |
179 | #define SetPageDirty(page) set_bit(PG_dirty, &(page)->flags) | |
180 | #define TestSetPageDirty(page) test_and_set_bit(PG_dirty, &(page)->flags) | |
181 | #define ClearPageDirty(page) clear_bit(PG_dirty, &(page)->flags) | |
242e5468 | 182 | #define __ClearPageDirty(page) __clear_bit(PG_dirty, &(page)->flags) |
1da177e4 LT |
183 | #define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags) |
184 | ||
1da177e4 | 185 | #define PageLRU(page) test_bit(PG_lru, &(page)->flags) |
8d438f96 NP |
186 | #define SetPageLRU(page) set_bit(PG_lru, &(page)->flags) |
187 | #define ClearPageLRU(page) clear_bit(PG_lru, &(page)->flags) | |
67453911 | 188 | #define __ClearPageLRU(page) __clear_bit(PG_lru, &(page)->flags) |
1da177e4 LT |
189 | |
190 | #define PageActive(page) test_bit(PG_active, &(page)->flags) | |
191 | #define SetPageActive(page) set_bit(PG_active, &(page)->flags) | |
192 | #define ClearPageActive(page) clear_bit(PG_active, &(page)->flags) | |
67453911 | 193 | #define __ClearPageActive(page) __clear_bit(PG_active, &(page)->flags) |
1da177e4 LT |
194 | |
195 | #define PageSlab(page) test_bit(PG_slab, &(page)->flags) | |
f205b2fe NP |
196 | #define __SetPageSlab(page) __set_bit(PG_slab, &(page)->flags) |
197 | #define __ClearPageSlab(page) __clear_bit(PG_slab, &(page)->flags) | |
1da177e4 LT |
198 | |
199 | #ifdef CONFIG_HIGHMEM | |
cbe37d09 | 200 | #define PageHighMem(page) is_highmem(page_zone(page)) |
1da177e4 LT |
201 | #else |
202 | #define PageHighMem(page) 0 /* needed to optimize away at compile time */ | |
203 | #endif | |
204 | ||
205 | #define PageChecked(page) test_bit(PG_checked, &(page)->flags) | |
206 | #define SetPageChecked(page) set_bit(PG_checked, &(page)->flags) | |
207 | #define ClearPageChecked(page) clear_bit(PG_checked, &(page)->flags) | |
208 | ||
c85b04c3 JF |
209 | #define PagePinned(page) test_bit(PG_pinned, &(page)->flags) |
210 | #define SetPagePinned(page) set_bit(PG_pinned, &(page)->flags) | |
211 | #define ClearPagePinned(page) clear_bit(PG_pinned, &(page)->flags) | |
212 | ||
1da177e4 LT |
213 | #define PageReserved(page) test_bit(PG_reserved, &(page)->flags) |
214 | #define SetPageReserved(page) set_bit(PG_reserved, &(page)->flags) | |
215 | #define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags) | |
216 | #define __ClearPageReserved(page) __clear_bit(PG_reserved, &(page)->flags) | |
217 | ||
218 | #define SetPagePrivate(page) set_bit(PG_private, &(page)->flags) | |
219 | #define ClearPagePrivate(page) clear_bit(PG_private, &(page)->flags) | |
220 | #define PagePrivate(page) test_bit(PG_private, &(page)->flags) | |
221 | #define __SetPagePrivate(page) __set_bit(PG_private, &(page)->flags) | |
222 | #define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags) | |
223 | ||
d688abf5 AM |
224 | /* |
225 | * Only test-and-set exist for PG_writeback. The unconditional operators are | |
226 | * risky: they bypass page accounting. | |
227 | */ | |
1da177e4 | 228 | #define PageWriteback(page) test_bit(PG_writeback, &(page)->flags) |
d688abf5 AM |
229 | #define TestSetPageWriteback(page) test_and_set_bit(PG_writeback, \ |
230 | &(page)->flags) | |
231 | #define TestClearPageWriteback(page) test_and_clear_bit(PG_writeback, \ | |
232 | &(page)->flags) | |
1da177e4 | 233 | |
676165a8 NP |
234 | #define PageBuddy(page) test_bit(PG_buddy, &(page)->flags) |
235 | #define __SetPageBuddy(page) __set_bit(PG_buddy, &(page)->flags) | |
236 | #define __ClearPageBuddy(page) __clear_bit(PG_buddy, &(page)->flags) | |
237 | ||
1da177e4 LT |
238 | #define PageMappedToDisk(page) test_bit(PG_mappedtodisk, &(page)->flags) |
239 | #define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags) | |
240 | #define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags) | |
d77c2d7c FW |
241 | |
242 | #define PageReadahead(page) test_bit(PG_readahead, &(page)->flags) | |
243 | #define SetPageReadahead(page) set_bit(PG_readahead, &(page)->flags) | |
244 | #define ClearPageReadahead(page) clear_bit(PG_readahead, &(page)->flags) | |
1da177e4 LT |
245 | |
246 | #define PageReclaim(page) test_bit(PG_reclaim, &(page)->flags) | |
247 | #define SetPageReclaim(page) set_bit(PG_reclaim, &(page)->flags) | |
248 | #define ClearPageReclaim(page) clear_bit(PG_reclaim, &(page)->flags) | |
249 | #define TestClearPageReclaim(page) test_and_clear_bit(PG_reclaim, &(page)->flags) | |
250 | ||
1da177e4 | 251 | #define PageCompound(page) test_bit(PG_compound, &(page)->flags) |
5e9dace8 NP |
252 | #define __SetPageCompound(page) __set_bit(PG_compound, &(page)->flags) |
253 | #define __ClearPageCompound(page) __clear_bit(PG_compound, &(page)->flags) | |
1da177e4 | 254 | |
d85f3385 | 255 | /* |
6d777953 CL |
256 | * PG_reclaim is used in combination with PG_compound to mark the |
257 | * head and tail of a compound page | |
258 | * | |
259 | * PG_compound & PG_reclaim => Tail page | |
260 | * PG_compound & ~PG_reclaim => Head page | |
d85f3385 | 261 | */ |
6d777953 CL |
262 | |
263 | #define PG_head_tail_mask ((1L << PG_compound) | (1L << PG_reclaim)) | |
264 | ||
a62f735c | 265 | #define PageTail(page) (((page)->flags & PG_head_tail_mask) \ |
6d777953 CL |
266 | == PG_head_tail_mask) |
267 | ||
268 | static inline void __SetPageTail(struct page *page) | |
269 | { | |
270 | page->flags |= PG_head_tail_mask; | |
271 | } | |
272 | ||
273 | static inline void __ClearPageTail(struct page *page) | |
274 | { | |
275 | page->flags &= ~PG_head_tail_mask; | |
276 | } | |
277 | ||
a62f735c | 278 | #define PageHead(page) (((page)->flags & PG_head_tail_mask) \ |
6d777953 CL |
279 | == (1L << PG_compound)) |
280 | #define __SetPageHead(page) __SetPageCompound(page) | |
281 | #define __ClearPageHead(page) __ClearPageCompound(page) | |
d85f3385 | 282 | |
1da177e4 LT |
283 | #ifdef CONFIG_SWAP |
284 | #define PageSwapCache(page) test_bit(PG_swapcache, &(page)->flags) | |
285 | #define SetPageSwapCache(page) set_bit(PG_swapcache, &(page)->flags) | |
286 | #define ClearPageSwapCache(page) clear_bit(PG_swapcache, &(page)->flags) | |
287 | #else | |
288 | #define PageSwapCache(page) 0 | |
289 | #endif | |
290 | ||
291 | #define PageUncached(page) test_bit(PG_uncached, &(page)->flags) | |
292 | #define SetPageUncached(page) set_bit(PG_uncached, &(page)->flags) | |
293 | #define ClearPageUncached(page) clear_bit(PG_uncached, &(page)->flags) | |
294 | ||
295 | struct page; /* forward declaration */ | |
296 | ||
fba2591b LT |
297 | extern void cancel_dirty_page(struct page *page, unsigned int account_size); |
298 | ||
1da177e4 LT |
299 | int test_clear_page_writeback(struct page *page); |
300 | int test_set_page_writeback(struct page *page); | |
301 | ||
1da177e4 LT |
302 | static inline void set_page_writeback(struct page *page) |
303 | { | |
304 | test_set_page_writeback(page); | |
305 | } | |
306 | ||
307 | #endif /* PAGE_FLAGS_H */ |