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 /* add others here before... */ 150 SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */ 151 }; 152 153 #define SWAP_CLUSTER_MAX 32 154 155 #define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */ 156 #define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */ 157 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */ 158 #define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */ 159 #define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */ 160 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */ 161 162 /* 163 * The in-memory structure used to track swap areas. 164 */ 165 struct swap_info_struct { 166 unsigned long flags; /* SWP_USED etc: see above */ 167 signed short prio; /* swap priority of this type */ 168 signed char type; /* strange name for an index */ 169 signed char next; /* next type on the swap list */ 170 unsigned int max; /* extent of the swap_map */ 171 unsigned char *swap_map; /* vmalloc'ed array of usage counts */ 172 unsigned int lowest_bit; /* index of first free in swap_map */ 173 unsigned int highest_bit; /* index of last free in swap_map */ 174 unsigned int pages; /* total of usable pages of swap */ 175 unsigned int inuse_pages; /* number of those currently in use */ 176 unsigned int cluster_next; /* likely index for next allocation */ 177 unsigned int cluster_nr; /* countdown to next cluster search */ 178 unsigned int lowest_alloc; /* while preparing discard cluster */ 179 unsigned int highest_alloc; /* while preparing discard cluster */ 180 struct swap_extent *curr_swap_extent; 181 struct swap_extent first_swap_extent; 182 struct block_device *bdev; /* swap device or bdev of swap file */ 183 struct file *swap_file; /* seldom referenced */ 184 unsigned int old_block_size; /* seldom referenced */ 185 }; 186 187 struct swap_list_t { 188 int head; /* head of priority-ordered swapfile list */ 189 int next; /* swapfile to be used next */ 190 }; 191 192 /* Swap 50% full? Release swapcache more aggressively.. */ 193 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages) 194 195 /* linux/mm/page_alloc.c */ 196 extern unsigned long totalram_pages; 197 extern unsigned long totalreserve_pages; 198 extern unsigned int nr_free_buffer_pages(void); 199 extern unsigned int nr_free_pagecache_pages(void); 200 201 /* Definition of global_page_state not available yet */ 202 #define nr_free_pages() global_page_state(NR_FREE_PAGES) 203 204 205 /* linux/mm/swap.c */ 206 extern void __lru_cache_add(struct page *, enum lru_list lru); 207 extern void lru_cache_add_lru(struct page *, enum lru_list lru); 208 extern void activate_page(struct page *); 209 extern void mark_page_accessed(struct page *); 210 extern void lru_add_drain(void); 211 extern int lru_add_drain_all(void); 212 extern void rotate_reclaimable_page(struct page *page); 213 extern void swap_setup(void); 214 215 extern void add_page_to_unevictable_list(struct page *page); 216 217 /** 218 * lru_cache_add: add a page to the page lists 219 * @page: the page to add 220 */ 221 static inline void lru_cache_add_anon(struct page *page) 222 { 223 __lru_cache_add(page, LRU_INACTIVE_ANON); 224 } 225 226 static inline void lru_cache_add_active_anon(struct page *page) 227 { 228 __lru_cache_add(page, LRU_ACTIVE_ANON); 229 } 230 231 static inline void lru_cache_add_file(struct page *page) 232 { 233 __lru_cache_add(page, LRU_INACTIVE_FILE); 234 } 235 236 static inline void lru_cache_add_active_file(struct page *page) 237 { 238 __lru_cache_add(page, LRU_ACTIVE_FILE); 239 } 240 241 /* linux/mm/vmscan.c */ 242 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 243 gfp_t gfp_mask, nodemask_t *mask); 244 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem, 245 gfp_t gfp_mask, bool noswap, 246 unsigned int swappiness); 247 extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem, 248 gfp_t gfp_mask, bool noswap, 249 unsigned int swappiness, 250 struct zone *zone, 251 int nid); 252 extern int __isolate_lru_page(struct page *page, int mode, int file); 253 extern unsigned long shrink_all_memory(unsigned long nr_pages); 254 extern int vm_swappiness; 255 extern int remove_mapping(struct address_space *mapping, struct page *page); 256 extern long vm_total_pages; 257 258 #ifdef CONFIG_NUMA 259 extern int zone_reclaim_mode; 260 extern int sysctl_min_unmapped_ratio; 261 extern int sysctl_min_slab_ratio; 262 extern int zone_reclaim(struct zone *, gfp_t, unsigned int); 263 #else 264 #define zone_reclaim_mode 0 265 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order) 266 { 267 return 0; 268 } 269 #endif 270 271 extern int page_evictable(struct page *page, struct vm_area_struct *vma); 272 extern void scan_mapping_unevictable_pages(struct address_space *); 273 274 extern unsigned long scan_unevictable_pages; 275 extern int scan_unevictable_handler(struct ctl_table *, int, 276 void __user *, size_t *, loff_t *); 277 extern int scan_unevictable_register_node(struct node *node); 278 extern void scan_unevictable_unregister_node(struct node *node); 279 280 extern int kswapd_run(int nid); 281 extern void kswapd_stop(int nid); 282 283 #ifdef CONFIG_MMU 284 /* linux/mm/shmem.c */ 285 extern int shmem_unuse(swp_entry_t entry, struct page *page); 286 #endif /* CONFIG_MMU */ 287 288 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *); 289 290 #ifdef CONFIG_SWAP 291 /* linux/mm/page_io.c */ 292 extern int swap_readpage(struct page *); 293 extern int swap_writepage(struct page *page, struct writeback_control *wbc); 294 extern void end_swap_bio_read(struct bio *bio, int err); 295 296 /* linux/mm/swap_state.c */ 297 extern struct address_space swapper_space; 298 #define total_swapcache_pages swapper_space.nrpages 299 extern void show_swap_cache_info(void); 300 extern int add_to_swap(struct page *); 301 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t); 302 extern void __delete_from_swap_cache(struct page *); 303 extern void delete_from_swap_cache(struct page *); 304 extern void free_page_and_swap_cache(struct page *); 305 extern void free_pages_and_swap_cache(struct page **, int); 306 extern struct page *lookup_swap_cache(swp_entry_t); 307 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, 308 struct vm_area_struct *vma, unsigned long addr); 309 extern struct page *swapin_readahead(swp_entry_t, gfp_t, 310 struct vm_area_struct *vma, unsigned long addr); 311 312 /* linux/mm/swapfile.c */ 313 extern long nr_swap_pages; 314 extern long total_swap_pages; 315 extern void si_swapinfo(struct sysinfo *); 316 extern swp_entry_t get_swap_page(void); 317 extern swp_entry_t get_swap_page_of_type(int); 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 /* linux/mm/thrash.c */ 335 extern struct mm_struct *swap_token_mm; 336 extern void grab_swap_token(struct mm_struct *); 337 extern void __put_swap_token(struct mm_struct *); 338 339 static inline int has_swap_token(struct mm_struct *mm) 340 { 341 return (mm == swap_token_mm); 342 } 343 344 static inline void put_swap_token(struct mm_struct *mm) 345 { 346 if (has_swap_token(mm)) 347 __put_swap_token(mm); 348 } 349 350 static inline void disable_swap_token(void) 351 { 352 put_swap_token(swap_token_mm); 353 } 354 355 #ifdef CONFIG_CGROUP_MEM_RES_CTLR 356 extern void 357 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout); 358 #else 359 static inline void 360 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) 361 { 362 } 363 #endif 364 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 365 extern void mem_cgroup_uncharge_swap(swp_entry_t ent); 366 #else 367 static inline void mem_cgroup_uncharge_swap(swp_entry_t ent) 368 { 369 } 370 #endif 371 372 #else /* CONFIG_SWAP */ 373 374 #define nr_swap_pages 0L 375 #define total_swap_pages 0L 376 #define total_swapcache_pages 0UL 377 378 #define si_swapinfo(val) \ 379 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 380 /* only sparc can not include linux/pagemap.h in this file 381 * so leave page_cache_release and release_pages undeclared... */ 382 #define free_page_and_swap_cache(page) \ 383 page_cache_release(page) 384 #define free_pages_and_swap_cache(pages, nr) \ 385 release_pages((pages), (nr), 0); 386 387 static inline void show_swap_cache_info(void) 388 { 389 } 390 391 #define free_swap_and_cache(swp) is_migration_entry(swp) 392 #define swapcache_prepare(swp) is_migration_entry(swp) 393 394 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) 395 { 396 return 0; 397 } 398 399 static inline void swap_shmem_alloc(swp_entry_t swp) 400 { 401 } 402 403 static inline int swap_duplicate(swp_entry_t swp) 404 { 405 return 0; 406 } 407 408 static inline void swap_free(swp_entry_t swp) 409 { 410 } 411 412 static inline void swapcache_free(swp_entry_t swp, struct page *page) 413 { 414 } 415 416 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 417 struct vm_area_struct *vma, unsigned long addr) 418 { 419 return NULL; 420 } 421 422 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 423 { 424 return 0; 425 } 426 427 static inline struct page *lookup_swap_cache(swp_entry_t swp) 428 { 429 return NULL; 430 } 431 432 static inline int add_to_swap(struct page *page) 433 { 434 return 0; 435 } 436 437 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, 438 gfp_t gfp_mask) 439 { 440 return -1; 441 } 442 443 static inline void __delete_from_swap_cache(struct page *page) 444 { 445 } 446 447 static inline void delete_from_swap_cache(struct page *page) 448 { 449 } 450 451 #define reuse_swap_page(page) (page_mapcount(page) == 1) 452 453 static inline int try_to_free_swap(struct page *page) 454 { 455 return 0; 456 } 457 458 static inline swp_entry_t get_swap_page(void) 459 { 460 swp_entry_t entry; 461 entry.val = 0; 462 return entry; 463 } 464 465 /* linux/mm/thrash.c */ 466 static inline void put_swap_token(struct mm_struct *mm) 467 { 468 } 469 470 static inline void grab_swap_token(struct mm_struct *mm) 471 { 472 } 473 474 static inline int has_swap_token(struct mm_struct *mm) 475 { 476 return 0; 477 } 478 479 static inline void disable_swap_token(void) 480 { 481 } 482 483 static inline void 484 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent) 485 { 486 } 487 488 #endif /* CONFIG_SWAP */ 489 #endif /* __KERNEL__*/ 490 #endif /* _LINUX_SWAP_H */ 491