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 <linux/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 /* 159 * Ratio between the present memory in the zone and the "gap" that 160 * we're allowing kswapd to shrink in addition to the per-zone high 161 * wmark, even for zones that already have the high wmark satisfied, 162 * in order to provide better per-zone lru behavior. We are ok to 163 * spend not more than 1% of the memory for this zone balancing "gap". 164 */ 165 #define KSWAPD_ZONE_BALANCE_GAP_RATIO 100 166 167 #define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */ 168 #define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */ 169 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */ 170 #define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */ 171 #define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */ 172 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */ 173 174 /* 175 * The in-memory structure used to track swap areas. 176 */ 177 struct swap_info_struct { 178 unsigned long flags; /* SWP_USED etc: see above */ 179 signed short prio; /* swap priority of this type */ 180 signed char type; /* strange name for an index */ 181 signed char next; /* next type on the swap list */ 182 unsigned int max; /* extent of the swap_map */ 183 unsigned char *swap_map; /* vmalloc'ed array of usage counts */ 184 unsigned int lowest_bit; /* index of first free in swap_map */ 185 unsigned int highest_bit; /* index of last free in swap_map */ 186 unsigned int pages; /* total of usable pages of swap */ 187 unsigned int inuse_pages; /* number of those currently in use */ 188 unsigned int cluster_next; /* likely index for next allocation */ 189 unsigned int cluster_nr; /* countdown to next cluster search */ 190 unsigned int lowest_alloc; /* while preparing discard cluster */ 191 unsigned int highest_alloc; /* while preparing discard cluster */ 192 struct swap_extent *curr_swap_extent; 193 struct swap_extent first_swap_extent; 194 struct block_device *bdev; /* swap device or bdev of swap file */ 195 struct file *swap_file; /* seldom referenced */ 196 unsigned int old_block_size; /* seldom referenced */ 197 }; 198 199 struct swap_list_t { 200 int head; /* head of priority-ordered swapfile list */ 201 int next; /* swapfile to be used next */ 202 }; 203 204 /* Swap 50% full? Release swapcache more aggressively.. */ 205 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages) 206 207 /* linux/mm/page_alloc.c */ 208 extern unsigned long totalram_pages; 209 extern unsigned long totalreserve_pages; 210 extern unsigned long dirty_balance_reserve; 211 extern unsigned int nr_free_buffer_pages(void); 212 extern unsigned int nr_free_pagecache_pages(void); 213 214 /* Definition of global_page_state not available yet */ 215 #define nr_free_pages() global_page_state(NR_FREE_PAGES) 216 217 218 /* linux/mm/swap.c */ 219 extern void __lru_cache_add(struct page *, enum lru_list lru); 220 extern void lru_cache_add_lru(struct page *, enum lru_list lru); 221 extern void lru_add_page_tail(struct zone* zone, 222 struct page *page, struct page *page_tail); 223 extern void activate_page(struct page *); 224 extern void mark_page_accessed(struct page *); 225 extern void lru_add_drain(void); 226 extern int lru_add_drain_all(void); 227 extern void rotate_reclaimable_page(struct page *page); 228 extern void deactivate_page(struct page *page); 229 extern void swap_setup(void); 230 231 extern void add_page_to_unevictable_list(struct page *page); 232 233 /** 234 * lru_cache_add: add a page to the page lists 235 * @page: the page to add 236 */ 237 static inline void lru_cache_add_anon(struct page *page) 238 { 239 __lru_cache_add(page, LRU_INACTIVE_ANON); 240 } 241 242 static inline void lru_cache_add_file(struct page *page) 243 { 244 __lru_cache_add(page, LRU_INACTIVE_FILE); 245 } 246 247 /* linux/mm/vmscan.c */ 248 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 249 gfp_t gfp_mask, nodemask_t *mask); 250 extern int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file); 251 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem, 252 gfp_t gfp_mask, bool noswap); 253 extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem, 254 gfp_t gfp_mask, bool noswap, 255 struct zone *zone, 256 unsigned long *nr_scanned); 257 extern unsigned long shrink_all_memory(unsigned long nr_pages); 258 extern int vm_swappiness; 259 extern int remove_mapping(struct address_space *mapping, struct page *page); 260 extern long vm_total_pages; 261 262 #ifdef CONFIG_NUMA 263 extern int zone_reclaim_mode; 264 extern int sysctl_min_unmapped_ratio; 265 extern int sysctl_min_slab_ratio; 266 extern int zone_reclaim(struct zone *, gfp_t, unsigned int); 267 #else 268 #define zone_reclaim_mode 0 269 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order) 270 { 271 return 0; 272 } 273 #endif 274 275 extern int page_evictable(struct page *page, struct vm_area_struct *vma); 276 extern void scan_mapping_unevictable_pages(struct address_space *); 277 278 extern unsigned long scan_unevictable_pages; 279 extern int scan_unevictable_handler(struct ctl_table *, int, 280 void __user *, size_t *, loff_t *); 281 #ifdef CONFIG_NUMA 282 extern int scan_unevictable_register_node(struct node *node); 283 extern void scan_unevictable_unregister_node(struct node *node); 284 #else 285 static inline int scan_unevictable_register_node(struct node *node) 286 { 287 return 0; 288 } 289 static inline void scan_unevictable_unregister_node(struct node *node) 290 { 291 } 292 #endif 293 294 extern int kswapd_run(int nid); 295 extern void kswapd_stop(int nid); 296 #ifdef CONFIG_CGROUP_MEM_RES_CTLR 297 extern int mem_cgroup_swappiness(struct mem_cgroup *mem); 298 #else 299 static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) 300 { 301 return vm_swappiness; 302 } 303 #endif 304 #ifdef CONFIG_SWAP 305 /* linux/mm/page_io.c */ 306 extern int swap_readpage(struct page *); 307 extern int swap_writepage(struct page *page, struct writeback_control *wbc); 308 extern void end_swap_bio_read(struct bio *bio, int err); 309 310 /* linux/mm/swap_state.c */ 311 extern struct address_space swapper_space; 312 #define total_swapcache_pages swapper_space.nrpages 313 extern void show_swap_cache_info(void); 314 extern int add_to_swap(struct page *); 315 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t); 316 extern void __delete_from_swap_cache(struct page *); 317 extern void delete_from_swap_cache(struct page *); 318 extern void free_page_and_swap_cache(struct page *); 319 extern void free_pages_and_swap_cache(struct page **, int); 320 extern struct page *lookup_swap_cache(swp_entry_t); 321 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, 322 struct vm_area_struct *vma, unsigned long addr); 323 extern struct page *swapin_readahead(swp_entry_t, gfp_t, 324 struct vm_area_struct *vma, unsigned long addr); 325 326 /* linux/mm/swapfile.c */ 327 extern long nr_swap_pages; 328 extern long total_swap_pages; 329 extern void si_swapinfo(struct sysinfo *); 330 extern swp_entry_t get_swap_page(void); 331 extern swp_entry_t get_swap_page_of_type(int); 332 extern int valid_swaphandles(swp_entry_t, unsigned long *); 333 extern int add_swap_count_continuation(swp_entry_t, gfp_t); 334 extern void swap_shmem_alloc(swp_entry_t); 335 extern int swap_duplicate(swp_entry_t); 336 extern int swapcache_prepare(swp_entry_t); 337 extern void swap_free(swp_entry_t); 338 extern void swapcache_free(swp_entry_t, struct page *page); 339 extern int free_swap_and_cache(swp_entry_t); 340 extern int swap_type_of(dev_t, sector_t, struct block_device **); 341 extern unsigned int count_swap_pages(int, int); 342 extern sector_t map_swap_page(struct page *, struct block_device **); 343 extern sector_t swapdev_block(int, pgoff_t); 344 extern int reuse_swap_page(struct page *); 345 extern int try_to_free_swap(struct page *); 346 struct backing_dev_info; 347 348 /* linux/mm/thrash.c */ 349 extern struct mm_struct *swap_token_mm; 350 extern void grab_swap_token(struct mm_struct *); 351 extern void __put_swap_token(struct mm_struct *); 352 extern void disable_swap_token(struct mem_cgroup *memcg); 353 354 static inline int has_swap_token(struct mm_struct *mm) 355 { 356 return (mm == swap_token_mm); 357 } 358 359 static inline void put_swap_token(struct mm_struct *mm) 360 { 361 if (has_swap_token(mm)) 362 __put_swap_token(mm); 363 } 364 365 #ifdef CONFIG_CGROUP_MEM_RES_CTLR 366 extern void 367 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout); 368 extern int mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep); 369 #else 370 static inline void 371 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) 372 { 373 } 374 #endif 375 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 376 extern void mem_cgroup_uncharge_swap(swp_entry_t ent); 377 #else 378 static inline void mem_cgroup_uncharge_swap(swp_entry_t ent) 379 { 380 } 381 #endif 382 383 #else /* CONFIG_SWAP */ 384 385 #define nr_swap_pages 0L 386 #define total_swap_pages 0L 387 #define total_swapcache_pages 0UL 388 389 #define si_swapinfo(val) \ 390 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 391 /* only sparc can not include linux/pagemap.h in this file 392 * so leave page_cache_release and release_pages undeclared... */ 393 #define free_page_and_swap_cache(page) \ 394 page_cache_release(page) 395 #define free_pages_and_swap_cache(pages, nr) \ 396 release_pages((pages), (nr), 0); 397 398 static inline void show_swap_cache_info(void) 399 { 400 } 401 402 #define free_swap_and_cache(swp) is_migration_entry(swp) 403 #define swapcache_prepare(swp) is_migration_entry(swp) 404 405 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) 406 { 407 return 0; 408 } 409 410 static inline void swap_shmem_alloc(swp_entry_t swp) 411 { 412 } 413 414 static inline int swap_duplicate(swp_entry_t swp) 415 { 416 return 0; 417 } 418 419 static inline void swap_free(swp_entry_t swp) 420 { 421 } 422 423 static inline void swapcache_free(swp_entry_t swp, struct page *page) 424 { 425 } 426 427 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 428 struct vm_area_struct *vma, unsigned long addr) 429 { 430 return NULL; 431 } 432 433 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 434 { 435 return 0; 436 } 437 438 static inline struct page *lookup_swap_cache(swp_entry_t swp) 439 { 440 return NULL; 441 } 442 443 static inline int add_to_swap(struct page *page) 444 { 445 return 0; 446 } 447 448 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, 449 gfp_t gfp_mask) 450 { 451 return -1; 452 } 453 454 static inline void __delete_from_swap_cache(struct page *page) 455 { 456 } 457 458 static inline void delete_from_swap_cache(struct page *page) 459 { 460 } 461 462 #define reuse_swap_page(page) (page_mapcount(page) == 1) 463 464 static inline int try_to_free_swap(struct page *page) 465 { 466 return 0; 467 } 468 469 static inline swp_entry_t get_swap_page(void) 470 { 471 swp_entry_t entry; 472 entry.val = 0; 473 return entry; 474 } 475 476 /* linux/mm/thrash.c */ 477 static inline void put_swap_token(struct mm_struct *mm) 478 { 479 } 480 481 static inline void grab_swap_token(struct mm_struct *mm) 482 { 483 } 484 485 static inline int has_swap_token(struct mm_struct *mm) 486 { 487 return 0; 488 } 489 490 static inline void disable_swap_token(struct mem_cgroup *memcg) 491 { 492 } 493 494 static inline void 495 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent) 496 { 497 } 498 499 #ifdef CONFIG_CGROUP_MEM_RES_CTLR 500 static inline int 501 mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep) 502 { 503 return 0; 504 } 505 #endif 506 507 #endif /* CONFIG_SWAP */ 508 #endif /* __KERNEL__*/ 509 #endif /* _LINUX_SWAP_H */ 510