Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Macros for manipulating and testing page->flags |
| 3 | */ |
| 4 | |
| 5 | #ifndef PAGE_FLAGS_H |
| 6 | #define PAGE_FLAGS_H |
| 7 | |
Andrew Morton | f886ed4 | 2006-06-23 02:03:06 -0700 | [diff] [blame] | 8 | #include <linux/types.h> |
Christoph Lameter | 9223b41 | 2008-04-28 02:12:48 -0700 | [diff] [blame] | 9 | #ifndef __GENERATING_BOUNDS_H |
Christoph Lameter | 6d77795 | 2007-05-06 14:49:40 -0700 | [diff] [blame] | 10 | #include <linux/mm_types.h> |
Christoph Lameter | 9223b41 | 2008-04-28 02:12:48 -0700 | [diff] [blame] | 11 | #include <linux/bounds.h> |
| 12 | #endif /* !__GENERATING_BOUNDS_H */ |
Andrew Morton | f886ed4 | 2006-06-23 02:03:06 -0700 | [diff] [blame] | 13 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | * |
Nick Piggin | da6052f | 2006-09-25 23:31:35 -0700 | [diff] [blame] | 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. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | * |
Nick Piggin | da6052f | 2006-09-25 23:31:35 -0700 | [diff] [blame] | 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. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | * |
Nick Piggin | da6052f | 2006-09-25 23:31:35 -0700 | [diff] [blame] | 37 | * PG_referenced, PG_reclaim are used for page reclaim for anonymous and |
| 38 | * file-backed pagecache (see mm/vmscan.c). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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... |
Nick Piggin | da6052f | 2006-09-25 23:31:35 -0700 | [diff] [blame] | 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 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | */ |
| 55 | |
| 56 | /* |
| 57 | * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break |
Andy Whitcroft | 91fc8ab | 2006-04-10 22:53:01 -0700 | [diff] [blame] | 58 | * locked- and dirty-page accounting. |
| 59 | * |
| 60 | * The page flags field is split into two parts, the main flags area |
| 61 | * which extends from the low bits upwards, and the fields area which |
| 62 | * extends from the high bits downwards. |
| 63 | * |
| 64 | * | FIELD | ... | FLAGS | |
Christoph Lameter | 9223b41 | 2008-04-28 02:12:48 -0700 | [diff] [blame] | 65 | * N-1 ^ 0 |
| 66 | * (NR_PAGEFLAGS) |
Andy Whitcroft | 91fc8ab | 2006-04-10 22:53:01 -0700 | [diff] [blame] | 67 | * |
Christoph Lameter | 9223b41 | 2008-04-28 02:12:48 -0700 | [diff] [blame] | 68 | * The fields area is reserved for fields mapping zone, node (for NUMA) and |
| 69 | * SPARSEMEM section (for variants of SPARSEMEM that require section ids like |
| 70 | * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | */ |
Christoph Lameter | e268318 | 2008-04-28 02:12:47 -0700 | [diff] [blame] | 72 | enum pageflags { |
| 73 | PG_locked, /* Page is locked. Don't touch. */ |
| 74 | PG_error, |
| 75 | PG_referenced, |
| 76 | PG_uptodate, |
| 77 | PG_dirty, |
| 78 | PG_lru, |
| 79 | PG_active, |
| 80 | PG_slab, |
| 81 | PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/ |
| 82 | PG_checked = PG_owner_priv_1, /* Used by some filesystems */ |
| 83 | PG_pinned = PG_owner_priv_1, /* Xen pinned pagetable */ |
| 84 | PG_arch_1, |
| 85 | PG_reserved, |
| 86 | PG_private, /* If pagecache, has fs-private data */ |
| 87 | PG_writeback, /* Page is under writeback */ |
| 88 | PG_compound, /* A compound page */ |
| 89 | PG_swapcache, /* Swap page: swp_entry_t in private */ |
| 90 | PG_mappedtodisk, /* Has blocks allocated on-disk */ |
| 91 | PG_reclaim, /* To be reclaimed asap */ |
| 92 | /* PG_readahead is only used for file reads; PG_reclaim is only for writes */ |
| 93 | PG_readahead = PG_reclaim, /* Reminder to do async read-ahead */ |
| 94 | PG_buddy, /* Page is free, on buddy lists */ |
Andrew Morton | f886ed4 | 2006-06-23 02:03:06 -0700 | [diff] [blame] | 95 | |
| 96 | #if (BITS_PER_LONG > 32) |
| 97 | /* |
| 98 | * 64-bit-only flags build down from bit 31 |
| 99 | * |
| 100 | * 32 bit -------------------------------| FIELDS | FLAGS | |
| 101 | * 64 bit | FIELDS | ?????? FLAGS | |
| 102 | * 63 32 0 |
| 103 | */ |
Christoph Lameter | e268318 | 2008-04-28 02:12:47 -0700 | [diff] [blame] | 104 | PG_uncached = 31, /* Page has been mapped as uncached */ |
Andrew Morton | f886ed4 | 2006-06-23 02:03:06 -0700 | [diff] [blame] | 105 | #endif |
Christoph Lameter | 9223b41 | 2008-04-28 02:12:48 -0700 | [diff] [blame] | 106 | __NR_PAGEFLAGS |
Christoph Lameter | e268318 | 2008-04-28 02:12:47 -0700 | [diff] [blame] | 107 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | |
Christoph Lameter | 9223b41 | 2008-04-28 02:12:48 -0700 | [diff] [blame] | 109 | #ifndef __GENERATING_BOUNDS_H |
| 110 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | /* |
Christoph Lameter | f94a62e | 2008-04-28 02:12:49 -0700 | [diff] [blame] | 112 | * Macros to create function definitions for page flags |
| 113 | */ |
| 114 | #define TESTPAGEFLAG(uname, lname) \ |
| 115 | static inline int Page##uname(struct page *page) \ |
| 116 | { return test_bit(PG_##lname, &page->flags); } |
| 117 | |
| 118 | #define SETPAGEFLAG(uname, lname) \ |
| 119 | static inline void SetPage##uname(struct page *page) \ |
| 120 | { set_bit(PG_##lname, &page->flags); } |
| 121 | |
| 122 | #define CLEARPAGEFLAG(uname, lname) \ |
| 123 | static inline void ClearPage##uname(struct page *page) \ |
| 124 | { clear_bit(PG_##lname, &page->flags); } |
| 125 | |
| 126 | #define __SETPAGEFLAG(uname, lname) \ |
| 127 | static inline void __SetPage##uname(struct page *page) \ |
| 128 | { __set_bit(PG_##lname, &page->flags); } |
| 129 | |
| 130 | #define __CLEARPAGEFLAG(uname, lname) \ |
| 131 | static inline void __ClearPage##uname(struct page *page) \ |
| 132 | { __clear_bit(PG_##lname, &page->flags); } |
| 133 | |
| 134 | #define TESTSETFLAG(uname, lname) \ |
| 135 | static inline int TestSetPage##uname(struct page *page) \ |
| 136 | { return test_and_set_bit(PG_##lname, &page->flags); } |
| 137 | |
| 138 | #define TESTCLEARFLAG(uname, lname) \ |
| 139 | static inline int TestClearPage##uname(struct page *page) \ |
| 140 | { return test_and_clear_bit(PG_##lname, &page->flags); } |
| 141 | |
| 142 | |
| 143 | #define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \ |
| 144 | SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname) |
| 145 | |
| 146 | #define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \ |
| 147 | __SETPAGEFLAG(uname, lname) __CLEARPAGEFLAG(uname, lname) |
| 148 | |
| 149 | #define TESTSCFLAG(uname, lname) \ |
| 150 | TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname) |
| 151 | |
Christoph Lameter | 6a1e7f77 | 2008-04-28 02:12:50 -0700 | [diff] [blame^] | 152 | struct page; /* forward declaration */ |
| 153 | |
| 154 | PAGEFLAG(Locked, locked) TESTSCFLAG(Locked, locked) |
| 155 | PAGEFLAG(Error, error) |
| 156 | PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced) |
| 157 | PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty) |
| 158 | PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru) |
| 159 | PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active) |
| 160 | __PAGEFLAG(Slab, slab) |
| 161 | PAGEFLAG(Checked, checked) /* Used by some filesystems */ |
| 162 | PAGEFLAG(Pinned, pinned) /* Xen pinned pagetable */ |
| 163 | PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved) |
| 164 | PAGEFLAG(Private, private) __CLEARPAGEFLAG(Private, private) |
| 165 | __SETPAGEFLAG(Private, private) |
| 166 | |
Christoph Lameter | f94a62e | 2008-04-28 02:12:49 -0700 | [diff] [blame] | 167 | /* |
Christoph Lameter | 6a1e7f77 | 2008-04-28 02:12:50 -0700 | [diff] [blame^] | 168 | * Only test-and-set exist for PG_writeback. The unconditional operators are |
| 169 | * risky: they bypass page accounting. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | */ |
Christoph Lameter | 6a1e7f77 | 2008-04-28 02:12:50 -0700 | [diff] [blame^] | 171 | TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback) |
| 172 | __PAGEFLAG(Buddy, buddy) |
| 173 | PAGEFLAG(MappedToDisk, mappedtodisk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 174 | |
Christoph Lameter | 6a1e7f77 | 2008-04-28 02:12:50 -0700 | [diff] [blame^] | 175 | /* PG_readahead is only used for file reads; PG_reclaim is only for writes */ |
| 176 | PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim) |
| 177 | PAGEFLAG(Readahead, readahead) /* Reminder to do async read-ahead */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | |
Christoph Lameter | 6a1e7f77 | 2008-04-28 02:12:50 -0700 | [diff] [blame^] | 179 | #ifdef CONFIG_HIGHMEM |
| 180 | /* |
| 181 | * Must use a macro here due to header dependency issues. page_zone() is not |
| 182 | * available at this point. |
| 183 | */ |
| 184 | #define PageHighMem(__p) is_highmem(page_zone(page)) |
| 185 | #else |
| 186 | static inline int PageHighMem(struct page *page) |
| 187 | { |
| 188 | return 0; |
| 189 | } |
| 190 | #endif |
| 191 | |
| 192 | #ifdef CONFIG_SWAP |
| 193 | PAGEFLAG(SwapCache, swapcache) |
| 194 | #else |
| 195 | static inline int PageSwapCache(struct page *page) |
| 196 | { |
| 197 | return 0; |
| 198 | } |
| 199 | #endif |
| 200 | |
| 201 | #if (BITS_PER_LONG > 32) |
| 202 | PAGEFLAG(Uncached, uncached) |
| 203 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | |
Nick Piggin | 0ed361d | 2008-02-04 22:29:34 -0800 | [diff] [blame] | 205 | static inline int PageUptodate(struct page *page) |
| 206 | { |
| 207 | int ret = test_bit(PG_uptodate, &(page)->flags); |
| 208 | |
| 209 | /* |
| 210 | * Must ensure that the data we read out of the page is loaded |
| 211 | * _after_ we've loaded page->flags to check for PageUptodate. |
| 212 | * We can skip the barrier if the page is not uptodate, because |
| 213 | * we wouldn't be reading anything from it. |
| 214 | * |
| 215 | * See SetPageUptodate() for the other side of the story. |
| 216 | */ |
| 217 | if (ret) |
| 218 | smp_rmb(); |
| 219 | |
| 220 | return ret; |
| 221 | } |
| 222 | |
| 223 | static inline void __SetPageUptodate(struct page *page) |
| 224 | { |
| 225 | smp_wmb(); |
| 226 | __set_bit(PG_uptodate, &(page)->flags); |
Christoph Lameter | f6ac235 | 2006-06-30 01:55:32 -0700 | [diff] [blame] | 227 | #ifdef CONFIG_S390 |
Nick Piggin | 0ed361d | 2008-02-04 22:29:34 -0800 | [diff] [blame] | 228 | page_clear_dirty(page); |
| 229 | #endif |
| 230 | } |
| 231 | |
Heiko Carstens | 2dcea57 | 2006-09-29 01:58:41 -0700 | [diff] [blame] | 232 | static inline void SetPageUptodate(struct page *page) |
| 233 | { |
Nick Piggin | 0ed361d | 2008-02-04 22:29:34 -0800 | [diff] [blame] | 234 | #ifdef CONFIG_S390 |
Heiko Carstens | 2dcea57 | 2006-09-29 01:58:41 -0700 | [diff] [blame] | 235 | if (!test_and_set_bit(PG_uptodate, &page->flags)) |
Martin Schwidefsky | 6c21048 | 2007-04-27 16:01:57 +0200 | [diff] [blame] | 236 | page_clear_dirty(page); |
Christoph Lameter | f6ac235 | 2006-06-30 01:55:32 -0700 | [diff] [blame] | 237 | #else |
Nick Piggin | 0ed361d | 2008-02-04 22:29:34 -0800 | [diff] [blame] | 238 | /* |
| 239 | * Memory barrier must be issued before setting the PG_uptodate bit, |
| 240 | * so that all previous stores issued in order to bring the page |
| 241 | * uptodate are actually visible before PageUptodate becomes true. |
| 242 | * |
| 243 | * s390 doesn't need an explicit smp_wmb here because the test and |
| 244 | * set bit already provides full barriers. |
| 245 | */ |
| 246 | smp_wmb(); |
| 247 | set_bit(PG_uptodate, &(page)->flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 248 | #endif |
Nick Piggin | 0ed361d | 2008-02-04 22:29:34 -0800 | [diff] [blame] | 249 | } |
| 250 | |
Christoph Lameter | 6a1e7f77 | 2008-04-28 02:12:50 -0700 | [diff] [blame^] | 251 | CLEARPAGEFLAG(Uptodate, uptodate) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | |
Linus Torvalds | fba2591 | 2006-12-20 13:46:42 -0800 | [diff] [blame] | 253 | extern void cancel_dirty_page(struct page *page, unsigned int account_size); |
| 254 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 255 | int test_clear_page_writeback(struct page *page); |
| 256 | int test_set_page_writeback(struct page *page); |
| 257 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | static inline void set_page_writeback(struct page *page) |
| 259 | { |
| 260 | test_set_page_writeback(page); |
| 261 | } |
| 262 | |
Christoph Lameter | 6a1e7f77 | 2008-04-28 02:12:50 -0700 | [diff] [blame^] | 263 | TESTPAGEFLAG(Compound, compound) |
| 264 | __PAGEFLAG(Head, compound) |
| 265 | |
| 266 | /* |
| 267 | * PG_reclaim is used in combination with PG_compound to mark the |
| 268 | * head and tail of a compound page. This saves one page flag |
| 269 | * but makes it impossible to use compound pages for the page cache. |
| 270 | * The PG_reclaim bit would have to be used for reclaim or readahead |
| 271 | * if compound pages enter the page cache. |
| 272 | * |
| 273 | * PG_compound & PG_reclaim => Tail page |
| 274 | * PG_compound & ~PG_reclaim => Head page |
| 275 | */ |
| 276 | #define PG_head_tail_mask ((1L << PG_compound) | (1L << PG_reclaim)) |
| 277 | |
| 278 | static inline int PageTail(struct page *page) |
| 279 | { |
| 280 | return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask); |
| 281 | } |
| 282 | |
| 283 | static inline void __SetPageTail(struct page *page) |
| 284 | { |
| 285 | page->flags |= PG_head_tail_mask; |
| 286 | } |
| 287 | |
| 288 | static inline void __ClearPageTail(struct page *page) |
| 289 | { |
| 290 | page->flags &= ~PG_head_tail_mask; |
| 291 | } |
| 292 | |
Christoph Lameter | 9223b41 | 2008-04-28 02:12:48 -0700 | [diff] [blame] | 293 | #endif /* !__GENERATING_BOUNDS_H */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 294 | #endif /* PAGE_FLAGS_H */ |