1 #ifndef _LINUX_SWAP_H 2 #define _LINUX_SWAP_H 3 4 #include <linux/spinlock.h> 5 #include <linux/linkage.h> 6 #include <linux/mmzone.h> 7 #include <linux/list.h> 8 #include <linux/memcontrol.h> 9 #include <linux/sched.h> 10 #include <linux/node.h> 11 12 #include <asm/atomic.h> 13 #include <asm/page.h> 14 15 struct notifier_block; 16 17 struct bio; 18 19 #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */ 20 #define SWAP_FLAG_PRIO_MASK 0x7fff 21 #define SWAP_FLAG_PRIO_SHIFT 0 22 #define SWAP_FLAG_DISCARD 0x10000 /* discard swap cluster after use */ 23 24 static inline int current_is_kswapd(void) 25 { 26 return current->flags & PF_KSWAPD; 27 } 28 29 /* 30 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can 31 * be swapped to. The swap type and the offset into that swap type are 32 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits 33 * for the type means that the maximum number of swapcache pages is 27 bits 34 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs 35 * the type/offset into the pte as 5/27 as well. 36 */ 37 #define MAX_SWAPFILES_SHIFT 5 38 39 /* 40 * Use some of the swap files numbers for other purposes. This 41 * is a convenient way to hook into the VM to trigger special 42 * actions on faults. 43 */ 44 45 /* 46 * NUMA node memory migration support 47 */ 48 #ifdef CONFIG_MIGRATION 49 #define SWP_MIGRATION_NUM 2 50 #define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM) 51 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1) 52 #else 53 #define SWP_MIGRATION_NUM 0 54 #endif 55 56 /* 57 * Handling of hardware poisoned pages with memory corruption. 58 */ 59 #ifdef CONFIG_MEMORY_FAILURE 60 #define SWP_HWPOISON_NUM 1 61 #define SWP_HWPOISON MAX_SWAPFILES 62 #else 63 #define SWP_HWPOISON_NUM 0 64 #endif 65 66 #define MAX_SWAPFILES \ 67 ((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM) 68 69 /* 70 * Magic header for a swap area. The first part of the union is 71 * what the swap magic looks like for the old (limited to 128MB) 72 * swap area format, the second part of the union adds - in the 73 * old reserved area - some extra information. Note that the first 74 * kilobyte is reserved for boot loader or disk label stuff... 75 * 76 * Having the magic at the end of the PAGE_SIZE makes detecting swap 77 * areas somewhat tricky on machines that support multiple page sizes. 78 * For 2.5 we'll probably want to move the magic to just beyond the 79 * bootbits... 80 */ 81 union swap_header { 82 struct { 83 char reserved[PAGE_SIZE - 10]; 84 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */ 85 } magic; 86 struct { 87 char bootbits[1024]; /* Space for disklabel etc. */ 88 __u32 version; 89 __u32 last_page; 90 __u32 nr_badpages; 91 unsigned char sws_uuid[16]; 92 unsigned char sws_volume[16]; 93 __u32 padding[117]; 94 __u32 badpages[1]; 95 } info; 96 }; 97 98 /* A swap entry has to fit into a "unsigned long", as 99 * the entry is hidden in the "index" field of the 100 * swapper address space. 101 */ 102 typedef struct { 103 unsigned long val; 104 } swp_entry_t; 105 106 /* 107 * current->reclaim_state points to one of these when a task is running 108 * memory reclaim 109 */ 110 struct reclaim_state { 111 unsigned long reclaimed_slab; 112 }; 113 114 #ifdef __KERNEL__ 115 116 struct address_space; 117 struct sysinfo; 118 struct writeback_control; 119 struct zone; 120 121 /* 122 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of 123 * disk blocks. A list of swap extents maps the entire swapfile. (Where the 124 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart 125 * from setup, they're handled identically. 126 * 127 * We always assume that blocks are of size PAGE_SIZE. 128 */ 129 struct swap_extent { 130 struct list_head list; 131 pgoff_t start_page; 132 pgoff_t nr_pages; 133 sector_t start_block; 134 }; 135 136 /* 137 * Max bad pages in the new format.. 138 */ 139 #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x) 140 #define MAX_SWAP_BADPAGES \ 141 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int)) 142 143 enum { 144 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */ 145 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */ 146 SWP_DISCARDABLE = (1 << 2), /* swapon+blkdev support discard */ 147 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */ 148 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */ 149 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */ 150 SWP_BLKDEV = (1 << 6), /* its a block device */ 151 /* add others here before... */ 152 SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */ 153 }; 154 155 #define SWAP_CLUSTER_MAX 32 156 #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX 157 158 #define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */ 159 #define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */ 160 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */ 161 #define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */ 162 #define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */ 163 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */ 164 165 /* 166 * The in-memory structure used to track swap areas. 167 */ 168 struct swap_info_struct { 169 unsigned long flags; /* SWP_USED etc: see above */ 170 signed short prio; /* swap priority of this type */ 171 signed char type; /* strange name for an index */ 172 signed char next; /* next type on the swap list */ 173 unsigned int max; /* extent of the swap_map */ 174 unsigned char *swap_map; /* vmalloc'ed array of usage counts */ 175 unsigned int lowest_bit; /* index of first free in swap_map */ 176 unsigned int highest_bit; /* index of last free in swap_map */ 177 unsigned int pages; /* total of usable pages of swap */ 178 unsigned int inuse_pages; /* number of those currently in use */ 179 unsigned int cluster_next; /* likely index for next allocation */ 180 unsigned int cluster_nr; /* countdown to next cluster search */ 181 unsigned int lowest_alloc; /* while preparing discard cluster */ 182 unsigned int highest_alloc; /* while preparing discard cluster */ 183 struct swap_extent *curr_swap_extent; 184 struct swap_extent first_swap_extent; 185 struct block_device *bdev; /* swap device or bdev of swap file */ 186 struct file *swap_file; /* seldom referenced */ 187 unsigned int old_block_size; /* seldom referenced */ 188 }; 189 190 struct swap_list_t { 191 int head; /* head of priority-ordered swapfile list */ 192 int next; /* swapfile to be used next */ 193 }; 194 195 /* Swap 50% full? Release swapcache more aggressively.. */ 196 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages) 197 198 /* linux/mm/page_alloc.c */ 199 extern unsigned long totalram_pages; 200 extern unsigned long totalreserve_pages; 201 extern unsigned int nr_free_buffer_pages(void); 202 extern unsigned int nr_free_pagecache_pages(void); 203 204 /* Definition of global_page_state not available yet */ 205 #define nr_free_pages() global_page_state(NR_FREE_PAGES) 206 207 208 /* linux/mm/swap.c */ 209 extern void __lru_cache_add(struct page *, enum lru_list lru); 210 extern void lru_cache_add_lru(struct page *, enum lru_list lru); 211 extern void activate_page(struct page *); 212 extern void mark_page_accessed(struct page *); 213 extern void lru_add_drain(void); 214 extern int lru_add_drain_all(void); 215 extern void rotate_reclaimable_page(struct page *page); 216 extern void swap_setup(void); 217 218 extern void add_page_to_unevictable_list(struct page *page); 219 220 /** 221 * lru_cache_add: add a page to the page lists 222 * @page: the page to add 223 */ 224 static inline void lru_cache_add_anon(struct page *page) 225 { 226 __lru_cache_add(page, LRU_INACTIVE_ANON); 227 } 228 229 static inline void lru_cache_add_file(struct page *page) 230 { 231 __lru_cache_add(page, LRU_INACTIVE_FILE); 232 } 233 234 /* LRU Isolation modes. */ 235 #define ISOLATE_INACTIVE 0 /* Isolate inactive pages. */ 236 #define ISOLATE_ACTIVE 1 /* Isolate active pages. */ 237 #define ISOLATE_BOTH 2 /* Isolate both active and inactive pages. */ 238 239 /* linux/mm/vmscan.c */ 240 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 241 gfp_t gfp_mask, nodemask_t *mask); 242 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem, 243 gfp_t gfp_mask, bool noswap, 244 unsigned int swappiness); 245 extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem, 246 gfp_t gfp_mask, bool noswap, 247 unsigned int swappiness, 248 struct zone *zone); 249 extern int __isolate_lru_page(struct page *page, int mode, int file); 250 extern unsigned long shrink_all_memory(unsigned long nr_pages); 251 extern int vm_swappiness; 252 extern int remove_mapping(struct address_space *mapping, struct page *page); 253 extern long vm_total_pages; 254 255 #ifdef CONFIG_NUMA 256 extern int zone_reclaim_mode; 257 extern int sysctl_min_unmapped_ratio; 258 extern int sysctl_min_slab_ratio; 259 extern int zone_reclaim(struct zone *, gfp_t, unsigned int); 260 #else 261 #define zone_reclaim_mode 0 262 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order) 263 { 264 return 0; 265 } 266 #endif 267 268 extern int page_evictable(struct page *page, struct vm_area_struct *vma); 269 extern void scan_mapping_unevictable_pages(struct address_space *); 270 271 extern unsigned long scan_unevictable_pages; 272 extern int scan_unevictable_handler(struct ctl_table *, int, 273 void __user *, size_t *, loff_t *); 274 #ifdef CONFIG_NUMA 275 extern int scan_unevictable_register_node(struct node *node); 276 extern void scan_unevictable_unregister_node(struct node *node); 277 #else 278 static inline int scan_unevictable_register_node(struct node *node) 279 { 280 return 0; 281 } 282 static inline void scan_unevictable_unregister_node(struct node *node) 283 { 284 } 285 #endif 286 287 extern int kswapd_run(int nid); 288 extern void kswapd_stop(int nid); 289 290 #ifdef CONFIG_MMU 291 /* linux/mm/shmem.c */ 292 extern int shmem_unuse(swp_entry_t entry, struct page *page); 293 #endif /* CONFIG_MMU */ 294 295 #ifdef CONFIG_CGROUP_MEM_RES_CTLR 296 extern void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff, 297 struct page **pagep, swp_entry_t *ent); 298 #endif 299 300 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *); 301 302 #ifdef CONFIG_SWAP 303 /* linux/mm/page_io.c */ 304 extern int swap_readpage(struct page *); 305 extern int swap_writepage(struct page *page, struct writeback_control *wbc); 306 extern void end_swap_bio_read(struct bio *bio, int err); 307 308 /* linux/mm/swap_state.c */ 309 extern struct address_space swapper_space; 310 #define total_swapcache_pages swapper_space.nrpages 311 extern void show_swap_cache_info(void); 312 extern int add_to_swap(struct page *); 313 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t); 314 extern void __delete_from_swap_cache(struct page *); 315 extern void delete_from_swap_cache(struct page *); 316 extern void free_page_and_swap_cache(struct page *); 317 extern void free_pages_and_swap_cache(struct page **, int); 318 extern struct page *lookup_swap_cache(swp_entry_t); 319 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, 320 struct vm_area_struct *vma, unsigned long addr); 321 extern struct page *swapin_readahead(swp_entry_t, gfp_t, 322 struct vm_area_struct *vma, unsigned long addr); 323 324 /* linux/mm/swapfile.c */ 325 extern long nr_swap_pages; 326 extern long total_swap_pages; 327 extern void si_swapinfo(struct sysinfo *); 328 extern swp_entry_t get_swap_page(void); 329 extern swp_entry_t get_swap_page_of_type(int); 330 extern int valid_swaphandles(swp_entry_t, unsigned long *); 331 extern int add_swap_count_continuation(swp_entry_t, gfp_t); 332 extern void swap_shmem_alloc(swp_entry_t); 333 extern int swap_duplicate(swp_entry_t); 334 extern int swapcache_prepare(swp_entry_t); 335 extern void swap_free(swp_entry_t); 336 extern void swapcache_free(swp_entry_t, struct page *page); 337 extern int free_swap_and_cache(swp_entry_t); 338 extern int swap_type_of(dev_t, sector_t, struct block_device **); 339 extern unsigned int count_swap_pages(int, int); 340 extern sector_t map_swap_page(struct page *, struct block_device **); 341 extern sector_t swapdev_block(int, pgoff_t); 342 extern int reuse_swap_page(struct page *); 343 extern int try_to_free_swap(struct page *); 344 struct backing_dev_info; 345 346 /* linux/mm/thrash.c */ 347 extern struct mm_struct *swap_token_mm; 348 extern void grab_swap_token(struct mm_struct *); 349 extern void __put_swap_token(struct mm_struct *); 350 351 static inline int has_swap_token(struct mm_struct *mm) 352 { 353 return (mm == swap_token_mm); 354 } 355 356 static inline void put_swap_token(struct mm_struct *mm) 357 { 358 if (has_swap_token(mm)) 359 __put_swap_token(mm); 360 } 361 362 static inline void disable_swap_token(void) 363 { 364 put_swap_token(swap_token_mm); 365 } 366 367 #ifdef CONFIG_CGROUP_MEM_RES_CTLR 368 extern void 369 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout); 370 extern int mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep); 371 #else 372 static inline void 373 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) 374 { 375 } 376 #endif 377 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 378 extern void mem_cgroup_uncharge_swap(swp_entry_t ent); 379 #else 380 static inline void mem_cgroup_uncharge_swap(swp_entry_t ent) 381 { 382 } 383 #endif 384 385 #else /* CONFIG_SWAP */ 386 387 #define nr_swap_pages 0L 388 #define total_swap_pages 0L 389 #define total_swapcache_pages 0UL 390 391 #define si_swapinfo(val) \ 392 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 393 /* only sparc can not include linux/pagemap.h in this file 394 * so leave page_cache_release and release_pages undeclared... */ 395 #define free_page_and_swap_cache(page) \ 396 page_cache_release(page) 397 #define free_pages_and_swap_cache(pages, nr) \ 398 release_pages((pages), (nr), 0); 399 400 static inline void show_swap_cache_info(void) 401 { 402 } 403 404 #define free_swap_and_cache(swp) is_migration_entry(swp) 405 #define swapcache_prepare(swp) is_migration_entry(swp) 406 407 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) 408 { 409 return 0; 410 } 411 412 static inline void swap_shmem_alloc(swp_entry_t swp) 413 { 414 } 415 416 static inline int swap_duplicate(swp_entry_t swp) 417 { 418 return 0; 419 } 420 421 static inline void swap_free(swp_entry_t swp) 422 { 423 } 424 425 static inline void swapcache_free(swp_entry_t swp, struct page *page) 426 { 427 } 428 429 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 430 struct vm_area_struct *vma, unsigned long addr) 431 { 432 return NULL; 433 } 434 435 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 436 { 437 return 0; 438 } 439 440 static inline struct page *lookup_swap_cache(swp_entry_t swp) 441 { 442 return NULL; 443 } 444 445 static inline int add_to_swap(struct page *page) 446 { 447 return 0; 448 } 449 450 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, 451 gfp_t gfp_mask) 452 { 453 return -1; 454 } 455 456 static inline void __delete_from_swap_cache(struct page *page) 457 { 458 } 459 460 static inline void delete_from_swap_cache(struct page *page) 461 { 462 } 463 464 #define reuse_swap_page(page) (page_mapcount(page) == 1) 465 466 static inline int try_to_free_swap(struct page *page) 467 { 468 return 0; 469 } 470 471 static inline swp_entry_t get_swap_page(void) 472 { 473 swp_entry_t entry; 474 entry.val = 0; 475 return entry; 476 } 477 478 /* linux/mm/thrash.c */ 479 static inline void put_swap_token(struct mm_struct *mm) 480 { 481 } 482 483 static inline void grab_swap_token(struct mm_struct *mm) 484 { 485 } 486 487 static inline int has_swap_token(struct mm_struct *mm) 488 { 489 return 0; 490 } 491 492 static inline void disable_swap_token(void) 493 { 494 } 495 496 static inline void 497 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent) 498 { 499 } 500 501 #ifdef CONFIG_CGROUP_MEM_RES_CTLR 502 static inline int 503 mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep) 504 { 505 return 0; 506 } 507 #endif 508 509 #endif /* CONFIG_SWAP */ 510 #endif /* __KERNEL__*/ 511 #endif /* _LINUX_SWAP_H */ 512