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[net-next-2.6.git] / include / linux / page-flags.h
CommitLineData
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
AM
8#include <linux/types.h>
9
1da177e4
LT
10/*
11 * Various page->flags bits:
12 *
13 * PG_reserved is set for special pages, which can never be swapped out. Some
14 * of them might not even exist (eg empty_bad_page)...
15 *
da6052f7
NP
16 * The PG_private bitflag is set on pagecache pages if they contain filesystem
17 * specific data (which is normally at page->private). It can be used by
18 * private allocations for its own usage.
1da177e4 19 *
da6052f7
NP
20 * During initiation of disk I/O, PG_locked is set. This bit is set before I/O
21 * and cleared when writeback _starts_ or when read _completes_. PG_writeback
22 * is set before writeback starts and cleared when it finishes.
23 *
24 * PG_locked also pins a page in pagecache, and blocks truncation of the file
25 * while it is held.
26 *
27 * page_waitqueue(page) is a wait queue of all tasks waiting for the page
28 * to become unlocked.
1da177e4
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29 *
30 * PG_uptodate tells whether the page's contents is valid. When a read
31 * completes, the page becomes uptodate, unless a disk I/O error happened.
32 *
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NP
33 * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
34 * file-backed pagecache (see mm/vmscan.c).
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35 *
36 * PG_error is set to indicate that an I/O error occurred on this page.
37 *
38 * PG_arch_1 is an architecture specific page state bit. The generic code
39 * guarantees that this bit is cleared for a page when it first is entered into
40 * the page cache.
41 *
42 * PG_highmem pages are not permanently mapped into the kernel virtual address
43 * space, they need to be kmapped separately for doing IO on the pages. The
44 * struct page (these bits with information) are always mapped into kernel
45 * address space...
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NP
46 *
47 * PG_buddy is set to indicate that the page is free and in the buddy system
48 * (see mm/page_alloc.c).
49 *
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50 */
51
52/*
53 * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
91fc8ab3
AW
54 * locked- and dirty-page accounting.
55 *
56 * The page flags field is split into two parts, the main flags area
57 * which extends from the low bits upwards, and the fields area which
58 * extends from the high bits downwards.
59 *
60 * | FIELD | ... | FLAGS |
61 * N-1 ^ 0
62 * (N-FLAGS_RESERVED)
63 *
64 * The fields area is reserved for fields mapping zone, node and SPARSEMEM
65 * section. The boundry between these two areas is defined by
66 * FLAGS_RESERVED which defines the width of the fields section
67 * (see linux/mmzone.h). New flags must _not_ overlap with this area.
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68 */
69#define PG_locked 0 /* Page is locked. Don't touch. */
70#define PG_error 1
71#define PG_referenced 2
72#define PG_uptodate 3
73
74#define PG_dirty 4
75#define PG_lru 5
76#define PG_active 6
77#define PG_slab 7 /* slab debug (Suparna wants this) */
78
cbe37d09
BP
79#define PG_checked 8 /* kill me in 2.5.<early>. */
80#define PG_arch_1 9
81#define PG_reserved 10
da6052f7 82#define PG_private 11 /* If pagecache, has fs-private data */
cbe37d09
BP
83
84#define PG_writeback 12 /* Page is under writeback */
85#define PG_nosave 13 /* Used for system suspend/resume */
86#define PG_compound 14 /* Part of a compound page */
87#define PG_swapcache 15 /* Swap page: swp_entry_t in private */
88
89#define PG_mappedtodisk 16 /* Has blocks allocated on-disk */
90#define PG_reclaim 17 /* To be reclaimed asap */
da6052f7 91#define PG_nosave_free 18 /* Used for system suspend/resume */
676165a8
NP
92#define PG_buddy 19 /* Page is free, on buddy lists */
93
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AM
94
95#if (BITS_PER_LONG > 32)
96/*
97 * 64-bit-only flags build down from bit 31
98 *
99 * 32 bit -------------------------------| FIELDS | FLAGS |
100 * 64 bit | FIELDS | ?????? FLAGS |
101 * 63 32 0
102 */
103#define PG_uncached 31 /* Page has been mapped as uncached */
104#endif
1da177e4 105
1da177e4
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106/*
107 * Manipulation of page state flags
108 */
109#define PageLocked(page) \
110 test_bit(PG_locked, &(page)->flags)
111#define SetPageLocked(page) \
112 set_bit(PG_locked, &(page)->flags)
113#define TestSetPageLocked(page) \
114 test_and_set_bit(PG_locked, &(page)->flags)
115#define ClearPageLocked(page) \
116 clear_bit(PG_locked, &(page)->flags)
117#define TestClearPageLocked(page) \
118 test_and_clear_bit(PG_locked, &(page)->flags)
119
120#define PageError(page) test_bit(PG_error, &(page)->flags)
121#define SetPageError(page) set_bit(PG_error, &(page)->flags)
122#define ClearPageError(page) clear_bit(PG_error, &(page)->flags)
123
124#define PageReferenced(page) test_bit(PG_referenced, &(page)->flags)
125#define SetPageReferenced(page) set_bit(PG_referenced, &(page)->flags)
126#define ClearPageReferenced(page) clear_bit(PG_referenced, &(page)->flags)
127#define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags)
128
129#define PageUptodate(page) test_bit(PG_uptodate, &(page)->flags)
f6ac2354
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130#ifdef CONFIG_S390
131#define SetPageUptodate(_page) \
132 do { \
133 struct page *__page = (_page); \
134 if (!test_and_set_bit(PG_uptodate, &__page->flags)) \
135 page_test_and_clear_dirty(_page); \
136 } while (0)
137#else
1da177e4
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138#define SetPageUptodate(page) set_bit(PG_uptodate, &(page)->flags)
139#endif
140#define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags)
141
142#define PageDirty(page) test_bit(PG_dirty, &(page)->flags)
143#define SetPageDirty(page) set_bit(PG_dirty, &(page)->flags)
144#define TestSetPageDirty(page) test_and_set_bit(PG_dirty, &(page)->flags)
145#define ClearPageDirty(page) clear_bit(PG_dirty, &(page)->flags)
242e5468 146#define __ClearPageDirty(page) __clear_bit(PG_dirty, &(page)->flags)
1da177e4
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147#define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags)
148
1da177e4 149#define PageLRU(page) test_bit(PG_lru, &(page)->flags)
8d438f96
NP
150#define SetPageLRU(page) set_bit(PG_lru, &(page)->flags)
151#define ClearPageLRU(page) clear_bit(PG_lru, &(page)->flags)
67453911 152#define __ClearPageLRU(page) __clear_bit(PG_lru, &(page)->flags)
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153
154#define PageActive(page) test_bit(PG_active, &(page)->flags)
155#define SetPageActive(page) set_bit(PG_active, &(page)->flags)
156#define ClearPageActive(page) clear_bit(PG_active, &(page)->flags)
67453911 157#define __ClearPageActive(page) __clear_bit(PG_active, &(page)->flags)
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158
159#define PageSlab(page) test_bit(PG_slab, &(page)->flags)
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NP
160#define __SetPageSlab(page) __set_bit(PG_slab, &(page)->flags)
161#define __ClearPageSlab(page) __clear_bit(PG_slab, &(page)->flags)
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162
163#ifdef CONFIG_HIGHMEM
cbe37d09 164#define PageHighMem(page) is_highmem(page_zone(page))
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165#else
166#define PageHighMem(page) 0 /* needed to optimize away at compile time */
167#endif
168
169#define PageChecked(page) test_bit(PG_checked, &(page)->flags)
170#define SetPageChecked(page) set_bit(PG_checked, &(page)->flags)
171#define ClearPageChecked(page) clear_bit(PG_checked, &(page)->flags)
172
173#define PageReserved(page) test_bit(PG_reserved, &(page)->flags)
174#define SetPageReserved(page) set_bit(PG_reserved, &(page)->flags)
175#define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags)
176#define __ClearPageReserved(page) __clear_bit(PG_reserved, &(page)->flags)
177
178#define SetPagePrivate(page) set_bit(PG_private, &(page)->flags)
179#define ClearPagePrivate(page) clear_bit(PG_private, &(page)->flags)
180#define PagePrivate(page) test_bit(PG_private, &(page)->flags)
181#define __SetPagePrivate(page) __set_bit(PG_private, &(page)->flags)
182#define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags)
183
184#define PageWriteback(page) test_bit(PG_writeback, &(page)->flags)
185#define SetPageWriteback(page) \
186 do { \
187 if (!test_and_set_bit(PG_writeback, \
188 &(page)->flags)) \
ce866b34 189 inc_zone_page_state(page, NR_WRITEBACK); \
1da177e4
LT
190 } while (0)
191#define TestSetPageWriteback(page) \
192 ({ \
193 int ret; \
194 ret = test_and_set_bit(PG_writeback, \
195 &(page)->flags); \
196 if (!ret) \
ce866b34 197 inc_zone_page_state(page, NR_WRITEBACK); \
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198 ret; \
199 })
200#define ClearPageWriteback(page) \
201 do { \
202 if (test_and_clear_bit(PG_writeback, \
203 &(page)->flags)) \
ce866b34 204 dec_zone_page_state(page, NR_WRITEBACK); \
1da177e4
LT
205 } while (0)
206#define TestClearPageWriteback(page) \
207 ({ \
208 int ret; \
209 ret = test_and_clear_bit(PG_writeback, \
210 &(page)->flags); \
211 if (ret) \
ce866b34 212 dec_zone_page_state(page, NR_WRITEBACK); \
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213 ret; \
214 })
215
216#define PageNosave(page) test_bit(PG_nosave, &(page)->flags)
217#define SetPageNosave(page) set_bit(PG_nosave, &(page)->flags)
218#define TestSetPageNosave(page) test_and_set_bit(PG_nosave, &(page)->flags)
219#define ClearPageNosave(page) clear_bit(PG_nosave, &(page)->flags)
220#define TestClearPageNosave(page) test_and_clear_bit(PG_nosave, &(page)->flags)
221
222#define PageNosaveFree(page) test_bit(PG_nosave_free, &(page)->flags)
223#define SetPageNosaveFree(page) set_bit(PG_nosave_free, &(page)->flags)
224#define ClearPageNosaveFree(page) clear_bit(PG_nosave_free, &(page)->flags)
225
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NP
226#define PageBuddy(page) test_bit(PG_buddy, &(page)->flags)
227#define __SetPageBuddy(page) __set_bit(PG_buddy, &(page)->flags)
228#define __ClearPageBuddy(page) __clear_bit(PG_buddy, &(page)->flags)
229
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230#define PageMappedToDisk(page) test_bit(PG_mappedtodisk, &(page)->flags)
231#define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags)
232#define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags)
233
234#define PageReclaim(page) test_bit(PG_reclaim, &(page)->flags)
235#define SetPageReclaim(page) set_bit(PG_reclaim, &(page)->flags)
236#define ClearPageReclaim(page) clear_bit(PG_reclaim, &(page)->flags)
237#define TestClearPageReclaim(page) test_and_clear_bit(PG_reclaim, &(page)->flags)
238
1da177e4 239#define PageCompound(page) test_bit(PG_compound, &(page)->flags)
5e9dace8
NP
240#define __SetPageCompound(page) __set_bit(PG_compound, &(page)->flags)
241#define __ClearPageCompound(page) __clear_bit(PG_compound, &(page)->flags)
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242
243#ifdef CONFIG_SWAP
244#define PageSwapCache(page) test_bit(PG_swapcache, &(page)->flags)
245#define SetPageSwapCache(page) set_bit(PG_swapcache, &(page)->flags)
246#define ClearPageSwapCache(page) clear_bit(PG_swapcache, &(page)->flags)
247#else
248#define PageSwapCache(page) 0
249#endif
250
251#define PageUncached(page) test_bit(PG_uncached, &(page)->flags)
252#define SetPageUncached(page) set_bit(PG_uncached, &(page)->flags)
253#define ClearPageUncached(page) clear_bit(PG_uncached, &(page)->flags)
254
255struct page; /* forward declaration */
256
257int test_clear_page_dirty(struct page *page);
258int test_clear_page_writeback(struct page *page);
259int test_set_page_writeback(struct page *page);
260
261static inline void clear_page_dirty(struct page *page)
262{
263 test_clear_page_dirty(page);
264}
265
266static inline void set_page_writeback(struct page *page)
267{
268 test_set_page_writeback(page);
269}
270
271#endif /* PAGE_FLAGS_H */