| 1 | /* |
| 2 | * Macros for manipulating and testing page->flags |
| 3 | */ |
| 4 | |
| 5 | #ifndef PAGE_FLAGS_H |
| 6 | #define PAGE_FLAGS_H |
| 7 | |
| 8 | #include <linux/types.h> |
| 9 | #include <linux/bug.h> |
| 10 | #include <linux/mmdebug.h> |
| 11 | #ifndef __GENERATING_BOUNDS_H |
| 12 | #include <linux/mm_types.h> |
| 13 | #include <generated/bounds.h> |
| 14 | #endif /* !__GENERATING_BOUNDS_H */ |
| 15 | |
| 16 | /* |
| 17 | * Various page->flags bits: |
| 18 | * |
| 19 | * PG_reserved is set for special pages, which can never be swapped out. Some |
| 20 | * of them might not even exist (eg empty_bad_page)... |
| 21 | * |
| 22 | * The PG_private bitflag is set on pagecache pages if they contain filesystem |
| 23 | * specific data (which is normally at page->private). It can be used by |
| 24 | * private allocations for its own usage. |
| 25 | * |
| 26 | * During initiation of disk I/O, PG_locked is set. This bit is set before I/O |
| 27 | * and cleared when writeback _starts_ or when read _completes_. PG_writeback |
| 28 | * is set before writeback starts and cleared when it finishes. |
| 29 | * |
| 30 | * PG_locked also pins a page in pagecache, and blocks truncation of the file |
| 31 | * while it is held. |
| 32 | * |
| 33 | * page_waitqueue(page) is a wait queue of all tasks waiting for the page |
| 34 | * to become unlocked. |
| 35 | * |
| 36 | * PG_uptodate tells whether the page's contents is valid. When a read |
| 37 | * completes, the page becomes uptodate, unless a disk I/O error happened. |
| 38 | * |
| 39 | * PG_referenced, PG_reclaim are used for page reclaim for anonymous and |
| 40 | * file-backed pagecache (see mm/vmscan.c). |
| 41 | * |
| 42 | * PG_error is set to indicate that an I/O error occurred on this page. |
| 43 | * |
| 44 | * PG_arch_1 is an architecture specific page state bit. The generic code |
| 45 | * guarantees that this bit is cleared for a page when it first is entered into |
| 46 | * the page cache. |
| 47 | * |
| 48 | * PG_highmem pages are not permanently mapped into the kernel virtual address |
| 49 | * space, they need to be kmapped separately for doing IO on the pages. The |
| 50 | * struct page (these bits with information) are always mapped into kernel |
| 51 | * address space... |
| 52 | * |
| 53 | * PG_hwpoison indicates that a page got corrupted in hardware and contains |
| 54 | * data with incorrect ECC bits that triggered a machine check. Accessing is |
| 55 | * not safe since it may cause another machine check. Don't touch! |
| 56 | */ |
| 57 | |
| 58 | /* |
| 59 | * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break |
| 60 | * locked- and dirty-page accounting. |
| 61 | * |
| 62 | * The page flags field is split into two parts, the main flags area |
| 63 | * which extends from the low bits upwards, and the fields area which |
| 64 | * extends from the high bits downwards. |
| 65 | * |
| 66 | * | FIELD | ... | FLAGS | |
| 67 | * N-1 ^ 0 |
| 68 | * (NR_PAGEFLAGS) |
| 69 | * |
| 70 | * The fields area is reserved for fields mapping zone, node (for NUMA) and |
| 71 | * SPARSEMEM section (for variants of SPARSEMEM that require section ids like |
| 72 | * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP). |
| 73 | */ |
| 74 | enum pageflags { |
| 75 | PG_locked, /* Page is locked. Don't touch. */ |
| 76 | PG_error, |
| 77 | PG_referenced, |
| 78 | PG_uptodate, |
| 79 | PG_dirty, |
| 80 | PG_lru, |
| 81 | PG_active, |
| 82 | PG_slab, |
| 83 | PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/ |
| 84 | PG_arch_1, |
| 85 | PG_reserved, |
| 86 | PG_private, /* If pagecache, has fs-private data */ |
| 87 | PG_private_2, /* If pagecache, has fs aux data */ |
| 88 | PG_writeback, /* Page is under writeback */ |
| 89 | PG_head, /* A head page */ |
| 90 | PG_swapcache, /* Swap page: swp_entry_t in private */ |
| 91 | PG_mappedtodisk, /* Has blocks allocated on-disk */ |
| 92 | PG_reclaim, /* To be reclaimed asap */ |
| 93 | PG_swapbacked, /* Page is backed by RAM/swap */ |
| 94 | PG_unevictable, /* Page is "unevictable" */ |
| 95 | #ifdef CONFIG_MMU |
| 96 | PG_mlocked, /* Page is vma mlocked */ |
| 97 | #endif |
| 98 | #ifdef CONFIG_ARCH_USES_PG_UNCACHED |
| 99 | PG_uncached, /* Page has been mapped as uncached */ |
| 100 | #endif |
| 101 | #ifdef CONFIG_MEMORY_FAILURE |
| 102 | PG_hwpoison, /* hardware poisoned page. Don't touch */ |
| 103 | #endif |
| 104 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| 105 | PG_compound_lock, |
| 106 | #endif |
| 107 | #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT) |
| 108 | PG_young, |
| 109 | PG_idle, |
| 110 | #endif |
| 111 | __NR_PAGEFLAGS, |
| 112 | |
| 113 | /* Filesystems */ |
| 114 | PG_checked = PG_owner_priv_1, |
| 115 | |
| 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 | |
| 122 | /* XEN */ |
| 123 | /* Pinned in Xen as a read-only pagetable page. */ |
| 124 | PG_pinned = PG_owner_priv_1, |
| 125 | /* Pinned as part of domain save (see xen_mm_pin_all()). */ |
| 126 | PG_savepinned = PG_dirty, |
| 127 | /* Has a grant mapping of another (foreign) domain's page. */ |
| 128 | PG_foreign = PG_owner_priv_1, |
| 129 | |
| 130 | /* SLOB */ |
| 131 | PG_slob_free = PG_private, |
| 132 | }; |
| 133 | |
| 134 | #ifndef __GENERATING_BOUNDS_H |
| 135 | |
| 136 | struct page; /* forward declaration */ |
| 137 | |
| 138 | static inline struct page *compound_head(struct page *page) |
| 139 | { |
| 140 | unsigned long head = READ_ONCE(page->compound_head); |
| 141 | |
| 142 | if (unlikely(head & 1)) |
| 143 | return (struct page *) (head - 1); |
| 144 | return page; |
| 145 | } |
| 146 | |
| 147 | static inline int PageTail(struct page *page) |
| 148 | { |
| 149 | return READ_ONCE(page->compound_head) & 1; |
| 150 | } |
| 151 | |
| 152 | static inline int PageCompound(struct page *page) |
| 153 | { |
| 154 | return test_bit(PG_head, &page->flags) || PageTail(page); |
| 155 | } |
| 156 | |
| 157 | /* |
| 158 | * Page flags policies wrt compound pages |
| 159 | * |
| 160 | * PF_ANY: |
| 161 | * the page flag is relevant for small, head and tail pages. |
| 162 | * |
| 163 | * PF_HEAD: |
| 164 | * for compound page all operations related to the page flag applied to |
| 165 | * head page. |
| 166 | * |
| 167 | * PF_NO_TAIL: |
| 168 | * modifications of the page flag must be done on small or head pages, |
| 169 | * checks can be done on tail pages too. |
| 170 | * |
| 171 | * PF_NO_COMPOUND: |
| 172 | * the page flag is not relevant for compound pages. |
| 173 | */ |
| 174 | #define PF_ANY(page, enforce) page |
| 175 | #define PF_HEAD(page, enforce) compound_head(page) |
| 176 | #define PF_NO_TAIL(page, enforce) ({ \ |
| 177 | VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \ |
| 178 | compound_head(page);}) |
| 179 | #define PF_NO_COMPOUND(page, enforce) ({ \ |
| 180 | VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \ |
| 181 | page;}) |
| 182 | |
| 183 | /* |
| 184 | * Macros to create function definitions for page flags |
| 185 | */ |
| 186 | #define TESTPAGEFLAG(uname, lname, policy) \ |
| 187 | static inline int Page##uname(struct page *page) \ |
| 188 | { return test_bit(PG_##lname, &policy(page, 0)->flags); } |
| 189 | |
| 190 | #define SETPAGEFLAG(uname, lname, policy) \ |
| 191 | static inline void SetPage##uname(struct page *page) \ |
| 192 | { set_bit(PG_##lname, &policy(page, 1)->flags); } |
| 193 | |
| 194 | #define CLEARPAGEFLAG(uname, lname, policy) \ |
| 195 | static inline void ClearPage##uname(struct page *page) \ |
| 196 | { clear_bit(PG_##lname, &policy(page, 1)->flags); } |
| 197 | |
| 198 | #define __SETPAGEFLAG(uname, lname, policy) \ |
| 199 | static inline void __SetPage##uname(struct page *page) \ |
| 200 | { __set_bit(PG_##lname, &policy(page, 1)->flags); } |
| 201 | |
| 202 | #define __CLEARPAGEFLAG(uname, lname, policy) \ |
| 203 | static inline void __ClearPage##uname(struct page *page) \ |
| 204 | { __clear_bit(PG_##lname, &policy(page, 1)->flags); } |
| 205 | |
| 206 | #define TESTSETFLAG(uname, lname, policy) \ |
| 207 | static inline int TestSetPage##uname(struct page *page) \ |
| 208 | { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); } |
| 209 | |
| 210 | #define TESTCLEARFLAG(uname, lname, policy) \ |
| 211 | static inline int TestClearPage##uname(struct page *page) \ |
| 212 | { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); } |
| 213 | |
| 214 | #define __TESTCLEARFLAG(uname, lname, policy) \ |
| 215 | static inline int __TestClearPage##uname(struct page *page) \ |
| 216 | { return __test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); } |
| 217 | |
| 218 | #define PAGEFLAG(uname, lname, policy) \ |
| 219 | TESTPAGEFLAG(uname, lname, policy) \ |
| 220 | SETPAGEFLAG(uname, lname, policy) \ |
| 221 | CLEARPAGEFLAG(uname, lname, policy) |
| 222 | |
| 223 | #define __PAGEFLAG(uname, lname, policy) \ |
| 224 | TESTPAGEFLAG(uname, lname, policy) \ |
| 225 | __SETPAGEFLAG(uname, lname, policy) \ |
| 226 | __CLEARPAGEFLAG(uname, lname, policy) |
| 227 | |
| 228 | #define TESTSCFLAG(uname, lname, policy) \ |
| 229 | TESTSETFLAG(uname, lname, policy) \ |
| 230 | TESTCLEARFLAG(uname, lname, policy) |
| 231 | |
| 232 | #define TESTPAGEFLAG_FALSE(uname) \ |
| 233 | static inline int Page##uname(const struct page *page) { return 0; } |
| 234 | |
| 235 | #define SETPAGEFLAG_NOOP(uname) \ |
| 236 | static inline void SetPage##uname(struct page *page) { } |
| 237 | |
| 238 | #define CLEARPAGEFLAG_NOOP(uname) \ |
| 239 | static inline void ClearPage##uname(struct page *page) { } |
| 240 | |
| 241 | #define __CLEARPAGEFLAG_NOOP(uname) \ |
| 242 | static inline void __ClearPage##uname(struct page *page) { } |
| 243 | |
| 244 | #define TESTSETFLAG_FALSE(uname) \ |
| 245 | static inline int TestSetPage##uname(struct page *page) { return 0; } |
| 246 | |
| 247 | #define TESTCLEARFLAG_FALSE(uname) \ |
| 248 | static inline int TestClearPage##uname(struct page *page) { return 0; } |
| 249 | |
| 250 | #define __TESTCLEARFLAG_FALSE(uname) \ |
| 251 | static inline int __TestClearPage##uname(struct page *page) { return 0; } |
| 252 | |
| 253 | #define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \ |
| 254 | SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname) |
| 255 | |
| 256 | #define TESTSCFLAG_FALSE(uname) \ |
| 257 | TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname) |
| 258 | |
| 259 | __PAGEFLAG(Locked, locked, PF_NO_TAIL) |
| 260 | PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND) |
| 261 | PAGEFLAG(Referenced, referenced, PF_HEAD) |
| 262 | TESTCLEARFLAG(Referenced, referenced, PF_HEAD) |
| 263 | __SETPAGEFLAG(Referenced, referenced, PF_HEAD) |
| 264 | PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD) |
| 265 | __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD) |
| 266 | PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD) |
| 267 | PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD) |
| 268 | TESTCLEARFLAG(Active, active, PF_HEAD) |
| 269 | __PAGEFLAG(Slab, slab, PF_NO_TAIL) |
| 270 | __PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL) |
| 271 | PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */ |
| 272 | |
| 273 | /* Xen */ |
| 274 | PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND) |
| 275 | TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND) |
| 276 | PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND); |
| 277 | PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND); |
| 278 | |
| 279 | PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) |
| 280 | __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) |
| 281 | PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) |
| 282 | __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) |
| 283 | __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) |
| 284 | |
| 285 | /* |
| 286 | * Private page markings that may be used by the filesystem that owns the page |
| 287 | * for its own purposes. |
| 288 | * - PG_private and PG_private_2 cause releasepage() and co to be invoked |
| 289 | */ |
| 290 | PAGEFLAG(Private, private, PF_ANY) __SETPAGEFLAG(Private, private, PF_ANY) |
| 291 | __CLEARPAGEFLAG(Private, private, PF_ANY) |
| 292 | PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY) |
| 293 | PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY) |
| 294 | TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY) |
| 295 | |
| 296 | /* |
| 297 | * Only test-and-set exist for PG_writeback. The unconditional operators are |
| 298 | * risky: they bypass page accounting. |
| 299 | */ |
| 300 | TESTPAGEFLAG(Writeback, writeback, PF_NO_COMPOUND) |
| 301 | TESTSCFLAG(Writeback, writeback, PF_NO_COMPOUND) |
| 302 | PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_COMPOUND) |
| 303 | |
| 304 | /* PG_readahead is only used for reads; PG_reclaim is only for writes */ |
| 305 | PAGEFLAG(Reclaim, reclaim, PF_NO_COMPOUND) |
| 306 | TESTCLEARFLAG(Reclaim, reclaim, PF_NO_COMPOUND) |
| 307 | PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND) |
| 308 | TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND) |
| 309 | |
| 310 | #ifdef CONFIG_HIGHMEM |
| 311 | /* |
| 312 | * Must use a macro here due to header dependency issues. page_zone() is not |
| 313 | * available at this point. |
| 314 | */ |
| 315 | #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p)) |
| 316 | #else |
| 317 | PAGEFLAG_FALSE(HighMem) |
| 318 | #endif |
| 319 | |
| 320 | #ifdef CONFIG_SWAP |
| 321 | PAGEFLAG(SwapCache, swapcache, PF_NO_COMPOUND) |
| 322 | #else |
| 323 | PAGEFLAG_FALSE(SwapCache) |
| 324 | #endif |
| 325 | |
| 326 | PAGEFLAG(Unevictable, unevictable, PF_HEAD) |
| 327 | __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD) |
| 328 | TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD) |
| 329 | |
| 330 | #ifdef CONFIG_MMU |
| 331 | PAGEFLAG(Mlocked, mlocked, PF_ANY) __CLEARPAGEFLAG(Mlocked, mlocked, PF_ANY) |
| 332 | TESTSCFLAG(Mlocked, mlocked, PF_ANY) __TESTCLEARFLAG(Mlocked, mlocked, PF_ANY) |
| 333 | #else |
| 334 | PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked) |
| 335 | TESTSCFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked) |
| 336 | #endif |
| 337 | |
| 338 | #ifdef CONFIG_ARCH_USES_PG_UNCACHED |
| 339 | PAGEFLAG(Uncached, uncached, PF_ANY) |
| 340 | #else |
| 341 | PAGEFLAG_FALSE(Uncached) |
| 342 | #endif |
| 343 | |
| 344 | #ifdef CONFIG_MEMORY_FAILURE |
| 345 | PAGEFLAG(HWPoison, hwpoison, PF_ANY) |
| 346 | TESTSCFLAG(HWPoison, hwpoison, PF_ANY) |
| 347 | #define __PG_HWPOISON (1UL << PG_hwpoison) |
| 348 | #else |
| 349 | PAGEFLAG_FALSE(HWPoison) |
| 350 | #define __PG_HWPOISON 0 |
| 351 | #endif |
| 352 | |
| 353 | #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT) |
| 354 | TESTPAGEFLAG(Young, young, PF_ANY) |
| 355 | SETPAGEFLAG(Young, young, PF_ANY) |
| 356 | TESTCLEARFLAG(Young, young, PF_ANY) |
| 357 | PAGEFLAG(Idle, idle, PF_ANY) |
| 358 | #endif |
| 359 | |
| 360 | /* |
| 361 | * On an anonymous page mapped into a user virtual memory area, |
| 362 | * page->mapping points to its anon_vma, not to a struct address_space; |
| 363 | * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h. |
| 364 | * |
| 365 | * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled, |
| 366 | * the PAGE_MAPPING_KSM bit may be set along with the PAGE_MAPPING_ANON bit; |
| 367 | * and then page->mapping points, not to an anon_vma, but to a private |
| 368 | * structure which KSM associates with that merged page. See ksm.h. |
| 369 | * |
| 370 | * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is currently never used. |
| 371 | * |
| 372 | * Please note that, confusingly, "page_mapping" refers to the inode |
| 373 | * address_space which maps the page from disk; whereas "page_mapped" |
| 374 | * refers to user virtual address space into which the page is mapped. |
| 375 | */ |
| 376 | #define PAGE_MAPPING_ANON 1 |
| 377 | #define PAGE_MAPPING_KSM 2 |
| 378 | #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM) |
| 379 | |
| 380 | static inline int PageAnon(struct page *page) |
| 381 | { |
| 382 | return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0; |
| 383 | } |
| 384 | |
| 385 | #ifdef CONFIG_KSM |
| 386 | /* |
| 387 | * A KSM page is one of those write-protected "shared pages" or "merged pages" |
| 388 | * which KSM maps into multiple mms, wherever identical anonymous page content |
| 389 | * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any |
| 390 | * anon_vma, but to that page's node of the stable tree. |
| 391 | */ |
| 392 | static inline int PageKsm(struct page *page) |
| 393 | { |
| 394 | return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == |
| 395 | (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM); |
| 396 | } |
| 397 | #else |
| 398 | TESTPAGEFLAG_FALSE(Ksm) |
| 399 | #endif |
| 400 | |
| 401 | u64 stable_page_flags(struct page *page); |
| 402 | |
| 403 | static inline int PageUptodate(struct page *page) |
| 404 | { |
| 405 | int ret = test_bit(PG_uptodate, &(page)->flags); |
| 406 | |
| 407 | /* |
| 408 | * Must ensure that the data we read out of the page is loaded |
| 409 | * _after_ we've loaded page->flags to check for PageUptodate. |
| 410 | * We can skip the barrier if the page is not uptodate, because |
| 411 | * we wouldn't be reading anything from it. |
| 412 | * |
| 413 | * See SetPageUptodate() for the other side of the story. |
| 414 | */ |
| 415 | if (ret) |
| 416 | smp_rmb(); |
| 417 | |
| 418 | return ret; |
| 419 | } |
| 420 | |
| 421 | static inline void __SetPageUptodate(struct page *page) |
| 422 | { |
| 423 | smp_wmb(); |
| 424 | __set_bit(PG_uptodate, &page->flags); |
| 425 | } |
| 426 | |
| 427 | static inline void SetPageUptodate(struct page *page) |
| 428 | { |
| 429 | /* |
| 430 | * Memory barrier must be issued before setting the PG_uptodate bit, |
| 431 | * so that all previous stores issued in order to bring the page |
| 432 | * uptodate are actually visible before PageUptodate becomes true. |
| 433 | */ |
| 434 | smp_wmb(); |
| 435 | set_bit(PG_uptodate, &page->flags); |
| 436 | } |
| 437 | |
| 438 | CLEARPAGEFLAG(Uptodate, uptodate, PF_ANY) |
| 439 | |
| 440 | int test_clear_page_writeback(struct page *page); |
| 441 | int __test_set_page_writeback(struct page *page, bool keep_write); |
| 442 | |
| 443 | #define test_set_page_writeback(page) \ |
| 444 | __test_set_page_writeback(page, false) |
| 445 | #define test_set_page_writeback_keepwrite(page) \ |
| 446 | __test_set_page_writeback(page, true) |
| 447 | |
| 448 | static inline void set_page_writeback(struct page *page) |
| 449 | { |
| 450 | test_set_page_writeback(page); |
| 451 | } |
| 452 | |
| 453 | static inline void set_page_writeback_keepwrite(struct page *page) |
| 454 | { |
| 455 | test_set_page_writeback_keepwrite(page); |
| 456 | } |
| 457 | |
| 458 | __PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY) |
| 459 | |
| 460 | static inline void set_compound_head(struct page *page, struct page *head) |
| 461 | { |
| 462 | WRITE_ONCE(page->compound_head, (unsigned long)head + 1); |
| 463 | } |
| 464 | |
| 465 | static inline void clear_compound_head(struct page *page) |
| 466 | { |
| 467 | WRITE_ONCE(page->compound_head, 0); |
| 468 | } |
| 469 | |
| 470 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| 471 | static inline void ClearPageCompound(struct page *page) |
| 472 | { |
| 473 | BUG_ON(!PageHead(page)); |
| 474 | ClearPageHead(page); |
| 475 | } |
| 476 | #endif |
| 477 | |
| 478 | #define PG_head_mask ((1L << PG_head)) |
| 479 | |
| 480 | #ifdef CONFIG_HUGETLB_PAGE |
| 481 | int PageHuge(struct page *page); |
| 482 | int PageHeadHuge(struct page *page); |
| 483 | bool page_huge_active(struct page *page); |
| 484 | #else |
| 485 | TESTPAGEFLAG_FALSE(Huge) |
| 486 | TESTPAGEFLAG_FALSE(HeadHuge) |
| 487 | |
| 488 | static inline bool page_huge_active(struct page *page) |
| 489 | { |
| 490 | return 0; |
| 491 | } |
| 492 | #endif |
| 493 | |
| 494 | |
| 495 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| 496 | /* |
| 497 | * PageHuge() only returns true for hugetlbfs pages, but not for |
| 498 | * normal or transparent huge pages. |
| 499 | * |
| 500 | * PageTransHuge() returns true for both transparent huge and |
| 501 | * hugetlbfs pages, but not normal pages. PageTransHuge() can only be |
| 502 | * called only in the core VM paths where hugetlbfs pages can't exist. |
| 503 | */ |
| 504 | static inline int PageTransHuge(struct page *page) |
| 505 | { |
| 506 | VM_BUG_ON_PAGE(PageTail(page), page); |
| 507 | return PageHead(page); |
| 508 | } |
| 509 | |
| 510 | /* |
| 511 | * PageTransCompound returns true for both transparent huge pages |
| 512 | * and hugetlbfs pages, so it should only be called when it's known |
| 513 | * that hugetlbfs pages aren't involved. |
| 514 | */ |
| 515 | static inline int PageTransCompound(struct page *page) |
| 516 | { |
| 517 | return PageCompound(page); |
| 518 | } |
| 519 | |
| 520 | /* |
| 521 | * PageTransTail returns true for both transparent huge pages |
| 522 | * and hugetlbfs pages, so it should only be called when it's known |
| 523 | * that hugetlbfs pages aren't involved. |
| 524 | */ |
| 525 | static inline int PageTransTail(struct page *page) |
| 526 | { |
| 527 | return PageTail(page); |
| 528 | } |
| 529 | |
| 530 | #else |
| 531 | TESTPAGEFLAG_FALSE(TransHuge) |
| 532 | TESTPAGEFLAG_FALSE(TransCompound) |
| 533 | TESTPAGEFLAG_FALSE(TransTail) |
| 534 | #endif |
| 535 | |
| 536 | /* |
| 537 | * PageBuddy() indicate that the page is free and in the buddy system |
| 538 | * (see mm/page_alloc.c). |
| 539 | * |
| 540 | * PAGE_BUDDY_MAPCOUNT_VALUE must be <= -2 but better not too close to |
| 541 | * -2 so that an underflow of the page_mapcount() won't be mistaken |
| 542 | * for a genuine PAGE_BUDDY_MAPCOUNT_VALUE. -128 can be created very |
| 543 | * efficiently by most CPU architectures. |
| 544 | */ |
| 545 | #define PAGE_BUDDY_MAPCOUNT_VALUE (-128) |
| 546 | |
| 547 | static inline int PageBuddy(struct page *page) |
| 548 | { |
| 549 | return atomic_read(&page->_mapcount) == PAGE_BUDDY_MAPCOUNT_VALUE; |
| 550 | } |
| 551 | |
| 552 | static inline void __SetPageBuddy(struct page *page) |
| 553 | { |
| 554 | VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page); |
| 555 | atomic_set(&page->_mapcount, PAGE_BUDDY_MAPCOUNT_VALUE); |
| 556 | } |
| 557 | |
| 558 | static inline void __ClearPageBuddy(struct page *page) |
| 559 | { |
| 560 | VM_BUG_ON_PAGE(!PageBuddy(page), page); |
| 561 | atomic_set(&page->_mapcount, -1); |
| 562 | } |
| 563 | |
| 564 | #define PAGE_BALLOON_MAPCOUNT_VALUE (-256) |
| 565 | |
| 566 | static inline int PageBalloon(struct page *page) |
| 567 | { |
| 568 | return atomic_read(&page->_mapcount) == PAGE_BALLOON_MAPCOUNT_VALUE; |
| 569 | } |
| 570 | |
| 571 | static inline void __SetPageBalloon(struct page *page) |
| 572 | { |
| 573 | VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page); |
| 574 | atomic_set(&page->_mapcount, PAGE_BALLOON_MAPCOUNT_VALUE); |
| 575 | } |
| 576 | |
| 577 | static inline void __ClearPageBalloon(struct page *page) |
| 578 | { |
| 579 | VM_BUG_ON_PAGE(!PageBalloon(page), page); |
| 580 | atomic_set(&page->_mapcount, -1); |
| 581 | } |
| 582 | |
| 583 | /* |
| 584 | * If network-based swap is enabled, sl*b must keep track of whether pages |
| 585 | * were allocated from pfmemalloc reserves. |
| 586 | */ |
| 587 | static inline int PageSlabPfmemalloc(struct page *page) |
| 588 | { |
| 589 | VM_BUG_ON_PAGE(!PageSlab(page), page); |
| 590 | return PageActive(page); |
| 591 | } |
| 592 | |
| 593 | static inline void SetPageSlabPfmemalloc(struct page *page) |
| 594 | { |
| 595 | VM_BUG_ON_PAGE(!PageSlab(page), page); |
| 596 | SetPageActive(page); |
| 597 | } |
| 598 | |
| 599 | static inline void __ClearPageSlabPfmemalloc(struct page *page) |
| 600 | { |
| 601 | VM_BUG_ON_PAGE(!PageSlab(page), page); |
| 602 | __ClearPageActive(page); |
| 603 | } |
| 604 | |
| 605 | static inline void ClearPageSlabPfmemalloc(struct page *page) |
| 606 | { |
| 607 | VM_BUG_ON_PAGE(!PageSlab(page), page); |
| 608 | ClearPageActive(page); |
| 609 | } |
| 610 | |
| 611 | #ifdef CONFIG_MMU |
| 612 | #define __PG_MLOCKED (1 << PG_mlocked) |
| 613 | #else |
| 614 | #define __PG_MLOCKED 0 |
| 615 | #endif |
| 616 | |
| 617 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| 618 | #define __PG_COMPOUND_LOCK (1 << PG_compound_lock) |
| 619 | #else |
| 620 | #define __PG_COMPOUND_LOCK 0 |
| 621 | #endif |
| 622 | |
| 623 | /* |
| 624 | * Flags checked when a page is freed. Pages being freed should not have |
| 625 | * these flags set. It they are, there is a problem. |
| 626 | */ |
| 627 | #define PAGE_FLAGS_CHECK_AT_FREE \ |
| 628 | (1 << PG_lru | 1 << PG_locked | \ |
| 629 | 1 << PG_private | 1 << PG_private_2 | \ |
| 630 | 1 << PG_writeback | 1 << PG_reserved | \ |
| 631 | 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \ |
| 632 | 1 << PG_unevictable | __PG_MLOCKED | \ |
| 633 | __PG_COMPOUND_LOCK) |
| 634 | |
| 635 | /* |
| 636 | * Flags checked when a page is prepped for return by the page allocator. |
| 637 | * Pages being prepped should not have these flags set. It they are set, |
| 638 | * there has been a kernel bug or struct page corruption. |
| 639 | * |
| 640 | * __PG_HWPOISON is exceptional because it needs to be kept beyond page's |
| 641 | * alloc-free cycle to prevent from reusing the page. |
| 642 | */ |
| 643 | #define PAGE_FLAGS_CHECK_AT_PREP \ |
| 644 | (((1 << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON) |
| 645 | |
| 646 | #define PAGE_FLAGS_PRIVATE \ |
| 647 | (1 << PG_private | 1 << PG_private_2) |
| 648 | /** |
| 649 | * page_has_private - Determine if page has private stuff |
| 650 | * @page: The page to be checked |
| 651 | * |
| 652 | * Determine if a page has private stuff, indicating that release routines |
| 653 | * should be invoked upon it. |
| 654 | */ |
| 655 | static inline int page_has_private(struct page *page) |
| 656 | { |
| 657 | return !!(page->flags & PAGE_FLAGS_PRIVATE); |
| 658 | } |
| 659 | |
| 660 | #undef PF_ANY |
| 661 | #undef PF_HEAD |
| 662 | #undef PF_NO_TAIL |
| 663 | #undef PF_NO_COMPOUND |
| 664 | #endif /* !__GENERATING_BOUNDS_H */ |
| 665 | |
| 666 | #endif /* PAGE_FLAGS_H */ |