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