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_ACTIVE = (SWP_USED | SWP_WRITEOK), 124 /* add others here before... */ 125 SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */ 126 }; 127 128 #define SWAP_CLUSTER_MAX 32 129 130 #define SWAP_MAP_MAX 0x7fff 131 #define SWAP_MAP_BAD 0x8000 132 133 /* 134 * The in-memory structure used to track swap areas. 135 */ 136 struct swap_info_struct { 137 unsigned int flags; 138 int prio; /* swap priority */ 139 struct file *swap_file; 140 struct block_device *bdev; 141 struct list_head extent_list; 142 struct swap_extent *curr_swap_extent; 143 unsigned old_block_size; 144 unsigned short * swap_map; 145 unsigned int lowest_bit; 146 unsigned int highest_bit; 147 unsigned int cluster_next; 148 unsigned int cluster_nr; 149 unsigned int pages; 150 unsigned int max; 151 unsigned int inuse_pages; 152 int next; /* next entry on swap list */ 153 }; 154 155 struct swap_list_t { 156 int head; /* head of priority-ordered swapfile list */ 157 int next; /* swapfile to be used next */ 158 }; 159 160 /* Swap 50% full? Release swapcache more aggressively.. */ 161 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages) 162 163 /* linux/mm/page_alloc.c */ 164 extern unsigned long totalram_pages; 165 extern unsigned long totalreserve_pages; 166 extern long nr_swap_pages; 167 extern unsigned int nr_free_buffer_pages(void); 168 extern unsigned int nr_free_pagecache_pages(void); 169 170 /* Definition of global_page_state not available yet */ 171 #define nr_free_pages() global_page_state(NR_FREE_PAGES) 172 173 174 /* linux/mm/swap.c */ 175 extern void __lru_cache_add(struct page *, enum lru_list lru); 176 extern void lru_cache_add_lru(struct page *, enum lru_list lru); 177 extern void lru_cache_add_active_or_unevictable(struct page *, 178 struct vm_area_struct *); 179 extern void activate_page(struct page *); 180 extern void mark_page_accessed(struct page *); 181 extern void lru_add_drain(void); 182 extern int lru_add_drain_all(void); 183 extern void rotate_reclaimable_page(struct page *page); 184 extern void swap_setup(void); 185 186 extern void add_page_to_unevictable_list(struct page *page); 187 188 /** 189 * lru_cache_add: add a page to the page lists 190 * @page: the page to add 191 */ 192 static inline void lru_cache_add_anon(struct page *page) 193 { 194 __lru_cache_add(page, LRU_INACTIVE_ANON); 195 } 196 197 static inline void lru_cache_add_active_anon(struct page *page) 198 { 199 __lru_cache_add(page, LRU_ACTIVE_ANON); 200 } 201 202 static inline void lru_cache_add_file(struct page *page) 203 { 204 __lru_cache_add(page, LRU_INACTIVE_FILE); 205 } 206 207 static inline void lru_cache_add_active_file(struct page *page) 208 { 209 __lru_cache_add(page, LRU_ACTIVE_FILE); 210 } 211 212 /* linux/mm/vmscan.c */ 213 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 214 gfp_t gfp_mask); 215 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem, 216 gfp_t gfp_mask); 217 extern int __isolate_lru_page(struct page *page, int mode, int file); 218 extern unsigned long shrink_all_memory(unsigned long nr_pages); 219 extern int vm_swappiness; 220 extern int remove_mapping(struct address_space *mapping, struct page *page); 221 extern long vm_total_pages; 222 223 #ifdef CONFIG_NUMA 224 extern int zone_reclaim_mode; 225 extern int sysctl_min_unmapped_ratio; 226 extern int sysctl_min_slab_ratio; 227 extern int zone_reclaim(struct zone *, gfp_t, unsigned int); 228 #else 229 #define zone_reclaim_mode 0 230 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order) 231 { 232 return 0; 233 } 234 #endif 235 236 #ifdef CONFIG_UNEVICTABLE_LRU 237 extern int page_evictable(struct page *page, struct vm_area_struct *vma); 238 extern void scan_mapping_unevictable_pages(struct address_space *); 239 240 extern unsigned long scan_unevictable_pages; 241 extern int scan_unevictable_handler(struct ctl_table *, int, struct file *, 242 void __user *, size_t *, loff_t *); 243 extern int scan_unevictable_register_node(struct node *node); 244 extern void scan_unevictable_unregister_node(struct node *node); 245 #else 246 static inline int page_evictable(struct page *page, 247 struct vm_area_struct *vma) 248 { 249 return 1; 250 } 251 252 static inline void scan_mapping_unevictable_pages(struct address_space *mapping) 253 { 254 } 255 256 static inline int scan_unevictable_register_node(struct node *node) 257 { 258 return 0; 259 } 260 261 static inline void scan_unevictable_unregister_node(struct node *node) { } 262 #endif 263 264 extern int kswapd_run(int nid); 265 266 #ifdef CONFIG_MMU 267 /* linux/mm/shmem.c */ 268 extern int shmem_unuse(swp_entry_t entry, struct page *page); 269 #endif /* CONFIG_MMU */ 270 271 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *); 272 273 #ifdef CONFIG_SWAP 274 /* linux/mm/page_io.c */ 275 extern int swap_readpage(struct file *, struct page *); 276 extern int swap_writepage(struct page *page, struct writeback_control *wbc); 277 extern void end_swap_bio_read(struct bio *bio, int err); 278 279 /* linux/mm/swap_state.c */ 280 extern struct address_space swapper_space; 281 #define total_swapcache_pages swapper_space.nrpages 282 extern void show_swap_cache_info(void); 283 extern int add_to_swap(struct page *, gfp_t); 284 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t); 285 extern void __delete_from_swap_cache(struct page *); 286 extern void delete_from_swap_cache(struct page *); 287 extern void free_page_and_swap_cache(struct page *); 288 extern void free_pages_and_swap_cache(struct page **, int); 289 extern struct page *lookup_swap_cache(swp_entry_t); 290 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, 291 struct vm_area_struct *vma, unsigned long addr); 292 extern struct page *swapin_readahead(swp_entry_t, gfp_t, 293 struct vm_area_struct *vma, unsigned long addr); 294 295 /* linux/mm/swapfile.c */ 296 extern long total_swap_pages; 297 extern void si_swapinfo(struct sysinfo *); 298 extern swp_entry_t get_swap_page(void); 299 extern swp_entry_t get_swap_page_of_type(int); 300 extern int swap_duplicate(swp_entry_t); 301 extern int valid_swaphandles(swp_entry_t, unsigned long *); 302 extern void swap_free(swp_entry_t); 303 extern void free_swap_and_cache(swp_entry_t); 304 extern int swap_type_of(dev_t, sector_t, struct block_device **); 305 extern unsigned int count_swap_pages(int, int); 306 extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t); 307 extern sector_t swapdev_block(int, pgoff_t); 308 extern struct swap_info_struct *get_swap_info_struct(unsigned); 309 extern int can_share_swap_page(struct page *); 310 extern int remove_exclusive_swap_page(struct page *); 311 extern int remove_exclusive_swap_page_ref(struct page *); 312 struct backing_dev_info; 313 314 /* linux/mm/thrash.c */ 315 extern struct mm_struct * swap_token_mm; 316 extern void grab_swap_token(void); 317 extern void __put_swap_token(struct mm_struct *); 318 319 static inline int has_swap_token(struct mm_struct *mm) 320 { 321 return (mm == swap_token_mm); 322 } 323 324 static inline void put_swap_token(struct mm_struct *mm) 325 { 326 if (has_swap_token(mm)) 327 __put_swap_token(mm); 328 } 329 330 static inline void disable_swap_token(void) 331 { 332 put_swap_token(swap_token_mm); 333 } 334 335 #else /* CONFIG_SWAP */ 336 337 #define total_swap_pages 0 338 #define total_swapcache_pages 0UL 339 340 #define si_swapinfo(val) \ 341 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 342 /* only sparc can not include linux/pagemap.h in this file 343 * so leave page_cache_release and release_pages undeclared... */ 344 #define free_page_and_swap_cache(page) \ 345 page_cache_release(page) 346 #define free_pages_and_swap_cache(pages, nr) \ 347 release_pages((pages), (nr), 0); 348 349 static inline void show_swap_cache_info(void) 350 { 351 } 352 353 static inline void free_swap_and_cache(swp_entry_t swp) 354 { 355 } 356 357 static inline int swap_duplicate(swp_entry_t swp) 358 { 359 return 0; 360 } 361 362 static inline void swap_free(swp_entry_t swp) 363 { 364 } 365 366 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 367 struct vm_area_struct *vma, unsigned long addr) 368 { 369 return NULL; 370 } 371 372 static inline struct page *lookup_swap_cache(swp_entry_t swp) 373 { 374 return NULL; 375 } 376 377 #define can_share_swap_page(p) (page_mapcount(p) == 1) 378 379 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, 380 gfp_t gfp_mask) 381 { 382 return -1; 383 } 384 385 static inline void __delete_from_swap_cache(struct page *page) 386 { 387 } 388 389 static inline void delete_from_swap_cache(struct page *page) 390 { 391 } 392 393 #define swap_token_default_timeout 0 394 395 static inline int remove_exclusive_swap_page(struct page *p) 396 { 397 return 0; 398 } 399 400 static inline int remove_exclusive_swap_page_ref(struct page *page) 401 { 402 return 0; 403 } 404 405 static inline swp_entry_t get_swap_page(void) 406 { 407 swp_entry_t entry; 408 entry.val = 0; 409 return entry; 410 } 411 412 /* linux/mm/thrash.c */ 413 #define put_swap_token(x) do { } while(0) 414 #define grab_swap_token() do { } while(0) 415 #define has_swap_token(x) 0 416 #define disable_swap_token() do { } while(0) 417 418 #endif /* CONFIG_SWAP */ 419 #endif /* __KERNEL__*/ 420 #endif /* _LINUX_SWAP_H */ 421