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 /* add others here before... */ 149 SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */ 150 }; 151 152 #define SWAP_CLUSTER_MAX 32 153 154 #define SWAP_MAP_MAX 0x7ffe 155 #define SWAP_MAP_BAD 0x7fff 156 #define SWAP_HAS_CACHE 0x8000 /* There is a swap cache of entry. */ 157 #define SWAP_COUNT_MASK (~SWAP_HAS_CACHE) 158 /* 159 * The in-memory structure used to track swap areas. 160 */ 161 struct swap_info_struct { 162 unsigned long flags; 163 int prio; /* swap priority */ 164 int next; /* next entry on swap list */ 165 struct file *swap_file; 166 struct block_device *bdev; 167 struct list_head extent_list; 168 struct swap_extent *curr_swap_extent; 169 unsigned short *swap_map; 170 unsigned int lowest_bit; 171 unsigned int highest_bit; 172 unsigned int lowest_alloc; /* while preparing discard cluster */ 173 unsigned int highest_alloc; /* while preparing discard cluster */ 174 unsigned int cluster_next; 175 unsigned int cluster_nr; 176 unsigned int pages; 177 unsigned int max; 178 unsigned int inuse_pages; 179 unsigned int old_block_size; 180 }; 181 182 struct swap_list_t { 183 int head; /* head of priority-ordered swapfile list */ 184 int next; /* swapfile to be used next */ 185 }; 186 187 /* Swap 50% full? Release swapcache more aggressively.. */ 188 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages) 189 190 /* linux/mm/page_alloc.c */ 191 extern unsigned long totalram_pages; 192 extern unsigned long totalreserve_pages; 193 extern unsigned int nr_free_buffer_pages(void); 194 extern unsigned int nr_free_pagecache_pages(void); 195 196 /* Definition of global_page_state not available yet */ 197 #define nr_free_pages() global_page_state(NR_FREE_PAGES) 198 199 200 /* linux/mm/swap.c */ 201 extern void __lru_cache_add(struct page *, enum lru_list lru); 202 extern void lru_cache_add_lru(struct page *, enum lru_list lru); 203 extern void activate_page(struct page *); 204 extern void mark_page_accessed(struct page *); 205 extern void lru_add_drain(void); 206 extern int lru_add_drain_all(void); 207 extern void rotate_reclaimable_page(struct page *page); 208 extern void swap_setup(void); 209 210 extern void add_page_to_unevictable_list(struct page *page); 211 212 /** 213 * lru_cache_add: add a page to the page lists 214 * @page: the page to add 215 */ 216 static inline void lru_cache_add_anon(struct page *page) 217 { 218 __lru_cache_add(page, LRU_INACTIVE_ANON); 219 } 220 221 static inline void lru_cache_add_active_anon(struct page *page) 222 { 223 __lru_cache_add(page, LRU_ACTIVE_ANON); 224 } 225 226 static inline void lru_cache_add_file(struct page *page) 227 { 228 __lru_cache_add(page, LRU_INACTIVE_FILE); 229 } 230 231 static inline void lru_cache_add_active_file(struct page *page) 232 { 233 __lru_cache_add(page, LRU_ACTIVE_FILE); 234 } 235 236 /* linux/mm/vmscan.c */ 237 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 238 gfp_t gfp_mask, nodemask_t *mask); 239 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem, 240 gfp_t gfp_mask, bool noswap, 241 unsigned int swappiness); 242 extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem, 243 gfp_t gfp_mask, bool noswap, 244 unsigned int swappiness, 245 struct zone *zone, 246 int nid); 247 extern int __isolate_lru_page(struct page *page, int mode, int file); 248 extern unsigned long shrink_all_memory(unsigned long nr_pages); 249 extern int vm_swappiness; 250 extern int remove_mapping(struct address_space *mapping, struct page *page); 251 extern long vm_total_pages; 252 253 #ifdef CONFIG_NUMA 254 extern int zone_reclaim_mode; 255 extern int sysctl_min_unmapped_ratio; 256 extern int sysctl_min_slab_ratio; 257 extern int zone_reclaim(struct zone *, gfp_t, unsigned int); 258 #else 259 #define zone_reclaim_mode 0 260 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order) 261 { 262 return 0; 263 } 264 #endif 265 266 extern int page_evictable(struct page *page, struct vm_area_struct *vma); 267 extern void scan_mapping_unevictable_pages(struct address_space *); 268 269 extern unsigned long scan_unevictable_pages; 270 extern int scan_unevictable_handler(struct ctl_table *, int, 271 void __user *, size_t *, loff_t *); 272 extern int scan_unevictable_register_node(struct node *node); 273 extern void scan_unevictable_unregister_node(struct node *node); 274 275 extern int kswapd_run(int nid); 276 277 #ifdef CONFIG_MMU 278 /* linux/mm/shmem.c */ 279 extern int shmem_unuse(swp_entry_t entry, struct page *page); 280 #endif /* CONFIG_MMU */ 281 282 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *); 283 284 #ifdef CONFIG_SWAP 285 /* linux/mm/page_io.c */ 286 extern int swap_readpage(struct page *); 287 extern int swap_writepage(struct page *page, struct writeback_control *wbc); 288 extern void end_swap_bio_read(struct bio *bio, int err); 289 290 /* linux/mm/swap_state.c */ 291 extern struct address_space swapper_space; 292 #define total_swapcache_pages swapper_space.nrpages 293 extern void show_swap_cache_info(void); 294 extern int add_to_swap(struct page *); 295 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t); 296 extern void __delete_from_swap_cache(struct page *); 297 extern void delete_from_swap_cache(struct page *); 298 extern void free_page_and_swap_cache(struct page *); 299 extern void free_pages_and_swap_cache(struct page **, int); 300 extern struct page *lookup_swap_cache(swp_entry_t); 301 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, 302 struct vm_area_struct *vma, unsigned long addr); 303 extern struct page *swapin_readahead(swp_entry_t, gfp_t, 304 struct vm_area_struct *vma, unsigned long addr); 305 306 /* linux/mm/swapfile.c */ 307 extern long nr_swap_pages; 308 extern long total_swap_pages; 309 extern void si_swapinfo(struct sysinfo *); 310 extern swp_entry_t get_swap_page(void); 311 extern swp_entry_t get_swap_page_of_type(int); 312 extern void swap_duplicate(swp_entry_t); 313 extern int swapcache_prepare(swp_entry_t); 314 extern int valid_swaphandles(swp_entry_t, unsigned long *); 315 extern void swap_free(swp_entry_t); 316 extern void swapcache_free(swp_entry_t, struct page *page); 317 extern int free_swap_and_cache(swp_entry_t); 318 extern int swap_type_of(dev_t, sector_t, struct block_device **); 319 extern unsigned int count_swap_pages(int, int); 320 extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t); 321 extern sector_t swapdev_block(int, pgoff_t); 322 extern struct swap_info_struct *get_swap_info_struct(unsigned); 323 extern int reuse_swap_page(struct page *); 324 extern int try_to_free_swap(struct page *); 325 struct backing_dev_info; 326 327 /* linux/mm/thrash.c */ 328 extern struct mm_struct *swap_token_mm; 329 extern void grab_swap_token(struct mm_struct *); 330 extern void __put_swap_token(struct mm_struct *); 331 332 static inline int has_swap_token(struct mm_struct *mm) 333 { 334 return (mm == swap_token_mm); 335 } 336 337 static inline void put_swap_token(struct mm_struct *mm) 338 { 339 if (has_swap_token(mm)) 340 __put_swap_token(mm); 341 } 342 343 static inline void disable_swap_token(void) 344 { 345 put_swap_token(swap_token_mm); 346 } 347 348 #ifdef CONFIG_CGROUP_MEM_RES_CTLR 349 extern void 350 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout); 351 #else 352 static inline void 353 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) 354 { 355 } 356 #endif 357 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 358 extern void mem_cgroup_uncharge_swap(swp_entry_t ent); 359 #else 360 static inline void mem_cgroup_uncharge_swap(swp_entry_t ent) 361 { 362 } 363 #endif 364 365 #else /* CONFIG_SWAP */ 366 367 #define nr_swap_pages 0L 368 #define total_swap_pages 0L 369 #define total_swapcache_pages 0UL 370 371 #define si_swapinfo(val) \ 372 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 373 /* only sparc can not include linux/pagemap.h in this file 374 * so leave page_cache_release and release_pages undeclared... */ 375 #define free_page_and_swap_cache(page) \ 376 page_cache_release(page) 377 #define free_pages_and_swap_cache(pages, nr) \ 378 release_pages((pages), (nr), 0); 379 380 static inline void show_swap_cache_info(void) 381 { 382 } 383 384 #define free_swap_and_cache(swp) is_migration_entry(swp) 385 #define swapcache_prepare(swp) is_migration_entry(swp) 386 387 static inline void swap_duplicate(swp_entry_t swp) 388 { 389 } 390 391 static inline void swap_free(swp_entry_t swp) 392 { 393 } 394 395 static inline void swapcache_free(swp_entry_t swp, struct page *page) 396 { 397 } 398 399 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 400 struct vm_area_struct *vma, unsigned long addr) 401 { 402 return NULL; 403 } 404 405 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 406 { 407 return 0; 408 } 409 410 static inline struct page *lookup_swap_cache(swp_entry_t swp) 411 { 412 return NULL; 413 } 414 415 static inline int add_to_swap(struct page *page) 416 { 417 return 0; 418 } 419 420 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, 421 gfp_t gfp_mask) 422 { 423 return -1; 424 } 425 426 static inline void __delete_from_swap_cache(struct page *page) 427 { 428 } 429 430 static inline void delete_from_swap_cache(struct page *page) 431 { 432 } 433 434 #define reuse_swap_page(page) (page_mapcount(page) == 1) 435 436 static inline int try_to_free_swap(struct page *page) 437 { 438 return 0; 439 } 440 441 static inline swp_entry_t get_swap_page(void) 442 { 443 swp_entry_t entry; 444 entry.val = 0; 445 return entry; 446 } 447 448 /* linux/mm/thrash.c */ 449 static inline void put_swap_token(struct mm_struct *mm) 450 { 451 } 452 453 static inline void grab_swap_token(struct mm_struct *mm) 454 { 455 } 456 457 static inline int has_swap_token(struct mm_struct *mm) 458 { 459 return 0; 460 } 461 462 static inline void disable_swap_token(void) 463 { 464 } 465 466 static inline void 467 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent) 468 { 469 } 470 471 #endif /* CONFIG_SWAP */ 472 #endif /* __KERNEL__*/ 473 #endif /* _LINUX_SWAP_H */ 474