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 #ifndef CONFIG_MIGRATION 38 #define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT) 39 #else 40 /* Use last two entries for page migration swap entries */ 41 #define MAX_SWAPFILES ((1 << MAX_SWAPFILES_SHIFT)-2) 42 #define SWP_MIGRATION_READ MAX_SWAPFILES 43 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + 1) 44 #endif 45 46 /* 47 * Magic header for a swap area. The first part of the union is 48 * what the swap magic looks like for the old (limited to 128MB) 49 * swap area format, the second part of the union adds - in the 50 * old reserved area - some extra information. Note that the first 51 * kilobyte is reserved for boot loader or disk label stuff... 52 * 53 * Having the magic at the end of the PAGE_SIZE makes detecting swap 54 * areas somewhat tricky on machines that support multiple page sizes. 55 * For 2.5 we'll probably want to move the magic to just beyond the 56 * bootbits... 57 */ 58 union swap_header { 59 struct { 60 char reserved[PAGE_SIZE - 10]; 61 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */ 62 } magic; 63 struct { 64 char bootbits[1024]; /* Space for disklabel etc. */ 65 __u32 version; 66 __u32 last_page; 67 __u32 nr_badpages; 68 unsigned char sws_uuid[16]; 69 unsigned char sws_volume[16]; 70 __u32 padding[117]; 71 __u32 badpages[1]; 72 } info; 73 }; 74 75 /* A swap entry has to fit into a "unsigned long", as 76 * the entry is hidden in the "index" field of the 77 * swapper address space. 78 */ 79 typedef struct { 80 unsigned long val; 81 } swp_entry_t; 82 83 /* 84 * current->reclaim_state points to one of these when a task is running 85 * memory reclaim 86 */ 87 struct reclaim_state { 88 unsigned long reclaimed_slab; 89 }; 90 91 #ifdef __KERNEL__ 92 93 struct address_space; 94 struct sysinfo; 95 struct writeback_control; 96 struct zone; 97 98 /* 99 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of 100 * disk blocks. A list of swap extents maps the entire swapfile. (Where the 101 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart 102 * from setup, they're handled identically. 103 * 104 * We always assume that blocks are of size PAGE_SIZE. 105 */ 106 struct swap_extent { 107 struct list_head list; 108 pgoff_t start_page; 109 pgoff_t nr_pages; 110 sector_t start_block; 111 }; 112 113 /* 114 * Max bad pages in the new format.. 115 */ 116 #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x) 117 #define MAX_SWAP_BADPAGES \ 118 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int)) 119 120 enum { 121 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */ 122 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */ 123 SWP_DISCARDABLE = (1 << 2), /* blkdev supports discard */ 124 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */ 125 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */ 126 /* add others here before... */ 127 SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */ 128 }; 129 130 #define SWAP_CLUSTER_MAX 32 131 132 #define SWAP_MAP_MAX 0x7ffe 133 #define SWAP_MAP_BAD 0x7fff 134 #define SWAP_HAS_CACHE 0x8000 /* There is a swap cache of entry. */ 135 #define SWAP_COUNT_MASK (~SWAP_HAS_CACHE) 136 /* 137 * The in-memory structure used to track swap areas. 138 */ 139 struct swap_info_struct { 140 unsigned long flags; 141 int prio; /* swap priority */ 142 int next; /* next entry on swap list */ 143 struct file *swap_file; 144 struct block_device *bdev; 145 struct list_head extent_list; 146 struct swap_extent *curr_swap_extent; 147 unsigned short *swap_map; 148 unsigned int lowest_bit; 149 unsigned int highest_bit; 150 unsigned int lowest_alloc; /* while preparing discard cluster */ 151 unsigned int highest_alloc; /* while preparing discard cluster */ 152 unsigned int cluster_next; 153 unsigned int cluster_nr; 154 unsigned int pages; 155 unsigned int max; 156 unsigned int inuse_pages; 157 unsigned int old_block_size; 158 }; 159 160 struct swap_list_t { 161 int head; /* head of priority-ordered swapfile list */ 162 int next; /* swapfile to be used next */ 163 }; 164 165 /* Swap 50% full? Release swapcache more aggressively.. */ 166 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages) 167 168 /* linux/mm/page_alloc.c */ 169 extern unsigned long totalram_pages; 170 extern unsigned long totalreserve_pages; 171 extern unsigned int nr_free_buffer_pages(void); 172 extern unsigned int nr_free_pagecache_pages(void); 173 174 /* Definition of global_page_state not available yet */ 175 #define nr_free_pages() global_page_state(NR_FREE_PAGES) 176 177 178 /* linux/mm/swap.c */ 179 extern void __lru_cache_add(struct page *, enum lru_list lru); 180 extern void lru_cache_add_lru(struct page *, enum lru_list lru); 181 extern void activate_page(struct page *); 182 extern void mark_page_accessed(struct page *); 183 extern void lru_add_drain(void); 184 extern int lru_add_drain_all(void); 185 extern void rotate_reclaimable_page(struct page *page); 186 extern void swap_setup(void); 187 188 extern void add_page_to_unevictable_list(struct page *page); 189 190 /** 191 * lru_cache_add: add a page to the page lists 192 * @page: the page to add 193 */ 194 static inline void lru_cache_add_anon(struct page *page) 195 { 196 __lru_cache_add(page, LRU_INACTIVE_ANON); 197 } 198 199 static inline void lru_cache_add_active_anon(struct page *page) 200 { 201 __lru_cache_add(page, LRU_ACTIVE_ANON); 202 } 203 204 static inline void lru_cache_add_file(struct page *page) 205 { 206 __lru_cache_add(page, LRU_INACTIVE_FILE); 207 } 208 209 static inline void lru_cache_add_active_file(struct page *page) 210 { 211 __lru_cache_add(page, LRU_ACTIVE_FILE); 212 } 213 214 /* linux/mm/vmscan.c */ 215 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 216 gfp_t gfp_mask, nodemask_t *mask); 217 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem, 218 gfp_t gfp_mask, bool noswap, 219 unsigned int swappiness); 220 extern int __isolate_lru_page(struct page *page, int mode, int file); 221 extern unsigned long shrink_all_memory(unsigned long nr_pages); 222 extern int vm_swappiness; 223 extern int remove_mapping(struct address_space *mapping, struct page *page); 224 extern long vm_total_pages; 225 226 #ifdef CONFIG_NUMA 227 extern int zone_reclaim_mode; 228 extern int sysctl_min_unmapped_ratio; 229 extern int sysctl_min_slab_ratio; 230 extern int zone_reclaim(struct zone *, gfp_t, unsigned int); 231 #else 232 #define zone_reclaim_mode 0 233 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order) 234 { 235 return 0; 236 } 237 #endif 238 239 extern int page_evictable(struct page *page, struct vm_area_struct *vma); 240 extern void scan_mapping_unevictable_pages(struct address_space *); 241 242 extern unsigned long scan_unevictable_pages; 243 extern int scan_unevictable_handler(struct ctl_table *, int, struct file *, 244 void __user *, size_t *, loff_t *); 245 extern int scan_unevictable_register_node(struct node *node); 246 extern void scan_unevictable_unregister_node(struct node *node); 247 248 extern int kswapd_run(int nid); 249 250 #ifdef CONFIG_MMU 251 /* linux/mm/shmem.c */ 252 extern int shmem_unuse(swp_entry_t entry, struct page *page); 253 #endif /* CONFIG_MMU */ 254 255 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *); 256 257 #ifdef CONFIG_SWAP 258 /* linux/mm/page_io.c */ 259 extern int swap_readpage(struct page *); 260 extern int swap_writepage(struct page *page, struct writeback_control *wbc); 261 extern void end_swap_bio_read(struct bio *bio, int err); 262 263 /* linux/mm/swap_state.c */ 264 extern struct address_space swapper_space; 265 #define total_swapcache_pages swapper_space.nrpages 266 extern void show_swap_cache_info(void); 267 extern int add_to_swap(struct page *); 268 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t); 269 extern void __delete_from_swap_cache(struct page *); 270 extern void delete_from_swap_cache(struct page *); 271 extern void free_page_and_swap_cache(struct page *); 272 extern void free_pages_and_swap_cache(struct page **, int); 273 extern struct page *lookup_swap_cache(swp_entry_t); 274 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, 275 struct vm_area_struct *vma, unsigned long addr); 276 extern struct page *swapin_readahead(swp_entry_t, gfp_t, 277 struct vm_area_struct *vma, unsigned long addr); 278 279 /* linux/mm/swapfile.c */ 280 extern long nr_swap_pages; 281 extern long total_swap_pages; 282 extern void si_swapinfo(struct sysinfo *); 283 extern swp_entry_t get_swap_page(void); 284 extern swp_entry_t get_swap_page_of_type(int); 285 extern void swap_duplicate(swp_entry_t); 286 extern int swapcache_prepare(swp_entry_t); 287 extern int valid_swaphandles(swp_entry_t, unsigned long *); 288 extern void swap_free(swp_entry_t); 289 extern void swapcache_free(swp_entry_t, struct page *page); 290 extern int free_swap_and_cache(swp_entry_t); 291 extern int swap_type_of(dev_t, sector_t, struct block_device **); 292 extern unsigned int count_swap_pages(int, int); 293 extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t); 294 extern sector_t swapdev_block(int, pgoff_t); 295 extern struct swap_info_struct *get_swap_info_struct(unsigned); 296 extern int reuse_swap_page(struct page *); 297 extern int try_to_free_swap(struct page *); 298 struct backing_dev_info; 299 300 /* linux/mm/thrash.c */ 301 extern struct mm_struct *swap_token_mm; 302 extern void grab_swap_token(struct mm_struct *); 303 extern void __put_swap_token(struct mm_struct *); 304 305 static inline int has_swap_token(struct mm_struct *mm) 306 { 307 return (mm == swap_token_mm); 308 } 309 310 static inline void put_swap_token(struct mm_struct *mm) 311 { 312 if (has_swap_token(mm)) 313 __put_swap_token(mm); 314 } 315 316 static inline void disable_swap_token(void) 317 { 318 put_swap_token(swap_token_mm); 319 } 320 321 #ifdef CONFIG_CGROUP_MEM_RES_CTLR 322 extern void 323 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout); 324 #else 325 static inline void 326 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) 327 { 328 } 329 #endif 330 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 331 extern void mem_cgroup_uncharge_swap(swp_entry_t ent); 332 #else 333 static inline void mem_cgroup_uncharge_swap(swp_entry_t ent) 334 { 335 } 336 #endif 337 338 #else /* CONFIG_SWAP */ 339 340 #define nr_swap_pages 0L 341 #define total_swap_pages 0L 342 #define total_swapcache_pages 0UL 343 344 #define si_swapinfo(val) \ 345 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 346 /* only sparc can not include linux/pagemap.h in this file 347 * so leave page_cache_release and release_pages undeclared... */ 348 #define free_page_and_swap_cache(page) \ 349 page_cache_release(page) 350 #define free_pages_and_swap_cache(pages, nr) \ 351 release_pages((pages), (nr), 0); 352 353 static inline void show_swap_cache_info(void) 354 { 355 } 356 357 #define free_swap_and_cache(swp) is_migration_entry(swp) 358 #define swapcache_prepare(swp) is_migration_entry(swp) 359 360 static inline void swap_duplicate(swp_entry_t swp) 361 { 362 } 363 364 static inline void swap_free(swp_entry_t swp) 365 { 366 } 367 368 static inline void swapcache_free(swp_entry_t swp, struct page *page) 369 { 370 } 371 372 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 373 struct vm_area_struct *vma, unsigned long addr) 374 { 375 return NULL; 376 } 377 378 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 379 { 380 return 0; 381 } 382 383 static inline struct page *lookup_swap_cache(swp_entry_t swp) 384 { 385 return NULL; 386 } 387 388 static inline int add_to_swap(struct page *page) 389 { 390 return 0; 391 } 392 393 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, 394 gfp_t gfp_mask) 395 { 396 return -1; 397 } 398 399 static inline void __delete_from_swap_cache(struct page *page) 400 { 401 } 402 403 static inline void delete_from_swap_cache(struct page *page) 404 { 405 } 406 407 #define reuse_swap_page(page) (page_mapcount(page) == 1) 408 409 static inline int try_to_free_swap(struct page *page) 410 { 411 return 0; 412 } 413 414 static inline swp_entry_t get_swap_page(void) 415 { 416 swp_entry_t entry; 417 entry.val = 0; 418 return entry; 419 } 420 421 /* linux/mm/thrash.c */ 422 #define put_swap_token(mm) do { } while (0) 423 #define grab_swap_token(mm) do { } while (0) 424 #define has_swap_token(mm) 0 425 #define disable_swap_token() do { } while (0) 426 427 static inline void 428 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent) 429 { 430 } 431 432 #endif /* CONFIG_SWAP */ 433 #endif /* __KERNEL__*/ 434 #endif /* _LINUX_SWAP_H */ 435