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Rev | Author | Line No. | Line |
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422 | giacomo | 1 | /* |
2 | * Macros for manipulating and testing page->flags |
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3 | */ |
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4 | |||
5 | #ifndef PAGE_FLAGS_H |
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6 | #define PAGE_FLAGS_H |
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7 | |||
8 | #include <linux/percpu.h> |
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9 | #include <linux/cache.h> |
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10 | #include <asm/pgtable.h> |
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11 | |||
12 | /* |
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13 | * Various page->flags bits: |
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14 | * |
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15 | * PG_reserved is set for special pages, which can never be swapped out. Some |
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16 | * of them might not even exist (eg empty_bad_page)... |
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17 | * |
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18 | * The PG_private bitflag is set if page->private contains a valid value. |
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19 | * |
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20 | * During disk I/O, PG_locked is used. This bit is set before I/O and |
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21 | * reset when I/O completes. page_waitqueue(page) is a wait queue of all tasks |
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22 | * waiting for the I/O on this page to complete. |
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23 | * |
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24 | * PG_uptodate tells whether the page's contents is valid. When a read |
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25 | * completes, the page becomes uptodate, unless a disk I/O error happened. |
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26 | * |
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27 | * For choosing which pages to swap out, inode pages carry a PG_referenced bit, |
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28 | * which is set any time the system accesses that page through the (mapping, |
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29 | * index) hash table. This referenced bit, together with the referenced bit |
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30 | * in the page tables, is used to manipulate page->age and move the page across |
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31 | * the active, inactive_dirty and inactive_clean lists. |
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32 | * |
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33 | * Note that the referenced bit, the page->lru list_head and the active, |
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34 | * inactive_dirty and inactive_clean lists are protected by the |
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35 | * zone->lru_lock, and *NOT* by the usual PG_locked bit! |
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36 | * |
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37 | * PG_error is set to indicate that an I/O error occurred on this page. |
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38 | * |
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39 | * PG_arch_1 is an architecture specific page state bit. The generic code |
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40 | * guarantees that this bit is cleared for a page when it first is entered into |
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41 | * the page cache. |
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42 | * |
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43 | * PG_highmem pages are not permanently mapped into the kernel virtual address |
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44 | * space, they need to be kmapped separately for doing IO on the pages. The |
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45 | * struct page (these bits with information) are always mapped into kernel |
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46 | * address space... |
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47 | */ |
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48 | |||
49 | /* |
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50 | * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break |
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51 | * locked- and dirty-page accounting. The top eight bits of page->flags are |
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52 | * used for page->zone, so putting flag bits there doesn't work. |
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53 | */ |
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54 | #define PG_locked 0 /* Page is locked. Don't touch. */ |
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55 | #define PG_error 1 |
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56 | #define PG_referenced 2 |
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57 | #define PG_uptodate 3 |
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58 | |||
59 | #define PG_dirty 4 |
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60 | #define PG_lru 5 |
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61 | #define PG_active 6 |
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62 | #define PG_slab 7 /* slab debug (Suparna wants this) */ |
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63 | |||
64 | #define PG_highmem 8 |
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65 | #define PG_checked 9 /* kill me in 2.5.<early>. */ |
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66 | #define PG_arch_1 10 |
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67 | #define PG_reserved 11 |
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68 | |||
69 | #define PG_private 12 /* Has something at ->private */ |
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70 | #define PG_writeback 13 /* Page is under writeback */ |
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71 | #define PG_nosave 14 /* Used for system suspend/resume */ |
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72 | #define PG_chainlock 15 /* lock bit for ->pte_chain */ |
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73 | |||
74 | #define PG_direct 16 /* ->pte_chain points directly at pte */ |
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75 | #define PG_mappedtodisk 17 /* Has blocks allocated on-disk */ |
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76 | #define PG_reclaim 18 /* To be reclaimed asap */ |
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77 | #define PG_compound 19 /* Part of a compound page */ |
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78 | |||
79 | |||
80 | /* |
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81 | * Global page accounting. One instance per CPU. Only unsigned longs are |
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82 | * allowed. |
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83 | */ |
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84 | struct page_state { |
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85 | unsigned long nr_dirty; /* Dirty writeable pages */ |
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86 | unsigned long nr_writeback; /* Pages under writeback */ |
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87 | unsigned long nr_unstable; /* NFS unstable pages */ |
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88 | unsigned long nr_page_table_pages;/* Pages used for pagetables */ |
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89 | unsigned long nr_mapped; /* mapped into pagetables */ |
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90 | unsigned long nr_slab; /* In slab */ |
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91 | #define GET_PAGE_STATE_LAST nr_slab |
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92 | |||
93 | /* |
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94 | * The below are zeroed by get_page_state(). Use get_full_page_state() |
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95 | * to add up all these. |
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96 | */ |
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97 | unsigned long pgpgin; /* Disk reads */ |
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98 | unsigned long pgpgout; /* Disk writes */ |
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99 | unsigned long pswpin; /* swap reads */ |
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100 | unsigned long pswpout; /* swap writes */ |
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101 | unsigned long pgalloc; /* page allocations */ |
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102 | |||
103 | unsigned long pgfree; /* page freeings */ |
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104 | unsigned long pgactivate; /* pages moved inactive->active */ |
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105 | unsigned long pgdeactivate; /* pages moved active->inactive */ |
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106 | unsigned long pgfault; /* faults (major+minor) */ |
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107 | unsigned long pgmajfault; /* faults (major only) */ |
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108 | |||
109 | unsigned long pgscan; /* pages scanned by page reclaim */ |
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110 | unsigned long pgrefill; /* inspected in refill_inactive_zone */ |
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111 | unsigned long pgsteal; /* total pages reclaimed */ |
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112 | unsigned long pginodesteal; /* pages reclaimed via inode freeing */ |
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113 | unsigned long kswapd_steal; /* pages reclaimed by kswapd */ |
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114 | |||
115 | unsigned long kswapd_inodesteal;/* reclaimed via kswapd inode freeing */ |
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116 | unsigned long pageoutrun; /* kswapd's calls to page reclaim */ |
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117 | unsigned long allocstall; /* direct reclaim calls */ |
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118 | unsigned long pgrotated; /* pages rotated to tail of the LRU */ |
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119 | } ____cacheline_aligned; |
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120 | |||
121 | DECLARE_PER_CPU(struct page_state, page_states); |
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122 | |||
123 | extern void get_page_state(struct page_state *ret); |
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124 | extern void get_full_page_state(struct page_state *ret); |
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125 | |||
126 | #define mod_page_state(member, delta) \ |
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127 | do { \ |
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128 | unsigned long flags; \ |
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129 | local_irq_save(flags); \ |
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130 | __get_cpu_var(page_states).member += (delta); \ |
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131 | local_irq_restore(flags); \ |
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132 | } while (0) |
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133 | |||
134 | #define inc_page_state(member) mod_page_state(member, 1UL) |
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135 | #define dec_page_state(member) mod_page_state(member, 0UL - 1) |
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136 | #define sub_page_state(member,delta) mod_page_state(member, 0UL - (delta)) |
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137 | |||
138 | |||
139 | /* |
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140 | * Manipulation of page state flags |
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141 | */ |
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142 | #define PageLocked(page) \ |
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143 | test_bit(PG_locked, &(page)->flags) |
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144 | #define SetPageLocked(page) \ |
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145 | set_bit(PG_locked, &(page)->flags) |
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146 | #define TestSetPageLocked(page) \ |
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147 | test_and_set_bit(PG_locked, &(page)->flags) |
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148 | #define ClearPageLocked(page) \ |
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149 | clear_bit(PG_locked, &(page)->flags) |
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150 | #define TestClearPageLocked(page) \ |
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151 | test_and_clear_bit(PG_locked, &(page)->flags) |
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152 | |||
153 | #define PageError(page) test_bit(PG_error, &(page)->flags) |
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154 | #define SetPageError(page) set_bit(PG_error, &(page)->flags) |
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155 | #define ClearPageError(page) clear_bit(PG_error, &(page)->flags) |
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156 | |||
157 | #define PageReferenced(page) test_bit(PG_referenced, &(page)->flags) |
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158 | #define SetPageReferenced(page) set_bit(PG_referenced, &(page)->flags) |
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159 | #define ClearPageReferenced(page) clear_bit(PG_referenced, &(page)->flags) |
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160 | #define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags) |
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161 | |||
162 | #ifndef arch_set_page_uptodate |
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163 | #define arch_set_page_uptodate(page) do { } while (0) |
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164 | #endif |
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165 | |||
166 | #define PageUptodate(page) test_bit(PG_uptodate, &(page)->flags) |
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167 | #define SetPageUptodate(page) \ |
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168 | do { \ |
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169 | arch_set_page_uptodate(page); \ |
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170 | set_bit(PG_uptodate, &(page)->flags); \ |
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171 | } while (0) |
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172 | #define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags) |
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173 | |||
174 | #define PageDirty(page) test_bit(PG_dirty, &(page)->flags) |
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175 | #define SetPageDirty(page) set_bit(PG_dirty, &(page)->flags) |
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176 | #define TestSetPageDirty(page) test_and_set_bit(PG_dirty, &(page)->flags) |
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177 | #define ClearPageDirty(page) clear_bit(PG_dirty, &(page)->flags) |
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178 | #define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags) |
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179 | |||
180 | #define SetPageLRU(page) set_bit(PG_lru, &(page)->flags) |
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181 | #define PageLRU(page) test_bit(PG_lru, &(page)->flags) |
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182 | #define TestSetPageLRU(page) test_and_set_bit(PG_lru, &(page)->flags) |
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183 | #define TestClearPageLRU(page) test_and_clear_bit(PG_lru, &(page)->flags) |
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184 | |||
185 | #define PageActive(page) test_bit(PG_active, &(page)->flags) |
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186 | #define SetPageActive(page) set_bit(PG_active, &(page)->flags) |
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187 | #define ClearPageActive(page) clear_bit(PG_active, &(page)->flags) |
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188 | #define TestClearPageActive(page) test_and_clear_bit(PG_active, &(page)->flags) |
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189 | #define TestSetPageActive(page) test_and_set_bit(PG_active, &(page)->flags) |
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190 | |||
191 | #define PageSlab(page) test_bit(PG_slab, &(page)->flags) |
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192 | #define SetPageSlab(page) set_bit(PG_slab, &(page)->flags) |
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193 | #define ClearPageSlab(page) clear_bit(PG_slab, &(page)->flags) |
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194 | #define TestClearPageSlab(page) test_and_clear_bit(PG_slab, &(page)->flags) |
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195 | #define TestSetPageSlab(page) test_and_set_bit(PG_slab, &(page)->flags) |
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196 | |||
197 | #ifdef CONFIG_HIGHMEM |
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198 | #define PageHighMem(page) test_bit(PG_highmem, &(page)->flags) |
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199 | #else |
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200 | #define PageHighMem(page) 0 /* needed to optimize away at compile time */ |
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201 | #endif |
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202 | |||
203 | #define PageChecked(page) test_bit(PG_checked, &(page)->flags) |
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204 | #define SetPageChecked(page) set_bit(PG_checked, &(page)->flags) |
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205 | #define ClearPageChecked(page) clear_bit(PG_checked, &(page)->flags) |
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206 | |||
207 | #define PageReserved(page) test_bit(PG_reserved, &(page)->flags) |
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208 | #define SetPageReserved(page) set_bit(PG_reserved, &(page)->flags) |
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209 | #define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags) |
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210 | |||
211 | #define SetPagePrivate(page) set_bit(PG_private, &(page)->flags) |
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212 | #define ClearPagePrivate(page) clear_bit(PG_private, &(page)->flags) |
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213 | #define PagePrivate(page) test_bit(PG_private, &(page)->flags) |
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214 | |||
215 | #define PageWriteback(page) test_bit(PG_writeback, &(page)->flags) |
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216 | #define SetPageWriteback(page) \ |
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217 | do { \ |
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218 | if (!test_and_set_bit(PG_writeback, \ |
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219 | &(page)->flags)) \ |
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220 | inc_page_state(nr_writeback); \ |
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221 | } while (0) |
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222 | #define TestSetPageWriteback(page) \ |
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223 | ({ \ |
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224 | int ret; \ |
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225 | ret = test_and_set_bit(PG_writeback, \ |
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226 | &(page)->flags); \ |
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227 | if (!ret) \ |
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228 | inc_page_state(nr_writeback); \ |
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229 | ret; \ |
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230 | }) |
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231 | #define ClearPageWriteback(page) \ |
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232 | do { \ |
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233 | if (test_and_clear_bit(PG_writeback, \ |
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234 | &(page)->flags)) \ |
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235 | dec_page_state(nr_writeback); \ |
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236 | } while (0) |
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237 | #define TestClearPageWriteback(page) \ |
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238 | ({ \ |
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239 | int ret; \ |
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240 | ret = test_and_clear_bit(PG_writeback, \ |
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241 | &(page)->flags); \ |
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242 | if (ret) \ |
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243 | dec_page_state(nr_writeback); \ |
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244 | ret; \ |
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245 | }) |
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246 | |||
247 | #define PageNosave(page) test_bit(PG_nosave, &(page)->flags) |
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248 | #define SetPageNosave(page) set_bit(PG_nosave, &(page)->flags) |
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249 | #define TestSetPageNosave(page) test_and_set_bit(PG_nosave, &(page)->flags) |
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250 | #define ClearPageNosave(page) clear_bit(PG_nosave, &(page)->flags) |
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251 | #define TestClearPageNosave(page) test_and_clear_bit(PG_nosave, &(page)->flags) |
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252 | |||
253 | #define PageDirect(page) test_bit(PG_direct, &(page)->flags) |
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254 | #define SetPageDirect(page) set_bit(PG_direct, &(page)->flags) |
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255 | #define TestSetPageDirect(page) test_and_set_bit(PG_direct, &(page)->flags) |
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256 | #define ClearPageDirect(page) clear_bit(PG_direct, &(page)->flags) |
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257 | #define TestClearPageDirect(page) test_and_clear_bit(PG_direct, &(page)->flags) |
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258 | |||
259 | #define PageMappedToDisk(page) test_bit(PG_mappedtodisk, &(page)->flags) |
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260 | #define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags) |
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261 | #define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags) |
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262 | |||
263 | #define PageReclaim(page) test_bit(PG_reclaim, &(page)->flags) |
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264 | #define SetPageReclaim(page) set_bit(PG_reclaim, &(page)->flags) |
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265 | #define ClearPageReclaim(page) clear_bit(PG_reclaim, &(page)->flags) |
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266 | #define TestClearPageReclaim(page) test_and_clear_bit(PG_reclaim, &(page)->flags) |
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267 | |||
268 | #define PageCompound(page) test_bit(PG_compound, &(page)->flags) |
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269 | #define SetPageCompound(page) set_bit(PG_compound, &(page)->flags) |
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270 | #define ClearPageCompound(page) clear_bit(PG_compound, &(page)->flags) |
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271 | |||
272 | /* |
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273 | * The PageSwapCache predicate doesn't use a PG_flag at this time, |
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274 | * but it may again do so one day. |
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275 | */ |
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276 | #ifdef CONFIG_SWAP |
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277 | extern struct address_space swapper_space; |
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278 | #define PageSwapCache(page) ((page)->mapping == &swapper_space) |
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279 | #else |
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280 | #define PageSwapCache(page) 0 |
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281 | #endif |
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282 | |||
283 | struct page; /* forward declaration */ |
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284 | |||
285 | int test_clear_page_dirty(struct page *page); |
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286 | |||
287 | static inline void clear_page_dirty(struct page *page) |
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288 | { |
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289 | test_clear_page_dirty(page); |
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290 | } |
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291 | |||
292 | #endif /* PAGE_FLAGS_H */ |