| 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 0x7fff |
| 133 | #define SWAP_MAP_BAD 0x8000 |
| 134 | |
| 135 | /* |
| 136 | * The in-memory structure used to track swap areas. |
| 137 | */ |
| 138 | struct swap_info_struct { |
| 139 | unsigned long flags; |
| 140 | int prio; /* swap priority */ |
| 141 | int next; /* next entry on swap list */ |
| 142 | struct file *swap_file; |
| 143 | struct block_device *bdev; |
| 144 | struct list_head extent_list; |
| 145 | struct swap_extent *curr_swap_extent; |
| 146 | unsigned short *swap_map; |
| 147 | unsigned int lowest_bit; |
| 148 | unsigned int highest_bit; |
| 149 | unsigned int lowest_alloc; /* while preparing discard cluster */ |
| 150 | unsigned int highest_alloc; /* while preparing discard cluster */ |
| 151 | unsigned int cluster_next; |
| 152 | unsigned int cluster_nr; |
| 153 | unsigned int pages; |
| 154 | unsigned int max; |
| 155 | unsigned int inuse_pages; |
| 156 | unsigned int old_block_size; |
| 157 | }; |
| 158 | |
| 159 | struct swap_list_t { |
| 160 | int head; /* head of priority-ordered swapfile list */ |
| 161 | int next; /* swapfile to be used next */ |
| 162 | }; |
| 163 | |
| 164 | /* Swap 50% full? Release swapcache more aggressively.. */ |
| 165 | #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages) |
| 166 | |
| 167 | /* linux/mm/page_alloc.c */ |
| 168 | extern unsigned long totalram_pages; |
| 169 | extern unsigned long totalreserve_pages; |
| 170 | extern unsigned int nr_free_buffer_pages(void); |
| 171 | extern unsigned int nr_free_pagecache_pages(void); |
| 172 | |
| 173 | /* Definition of global_page_state not available yet */ |
| 174 | #define nr_free_pages() global_page_state(NR_FREE_PAGES) |
| 175 | |
| 176 | |
| 177 | /* linux/mm/swap.c */ |
| 178 | extern void __lru_cache_add(struct page *, enum lru_list lru); |
| 179 | extern void lru_cache_add_lru(struct page *, enum lru_list lru); |
| 180 | extern void activate_page(struct page *); |
| 181 | extern void mark_page_accessed(struct page *); |
| 182 | extern void lru_add_drain(void); |
| 183 | extern int lru_add_drain_all(void); |
| 184 | extern void rotate_reclaimable_page(struct page *page); |
| 185 | extern void swap_setup(void); |
| 186 | |
| 187 | extern void add_page_to_unevictable_list(struct page *page); |
| 188 | |
| 189 | /** |
| 190 | * lru_cache_add: add a page to the page lists |
| 191 | * @page: the page to add |
| 192 | */ |
| 193 | static inline void lru_cache_add_anon(struct page *page) |
| 194 | { |
| 195 | __lru_cache_add(page, LRU_INACTIVE_ANON); |
| 196 | } |
| 197 | |
| 198 | static inline void lru_cache_add_active_anon(struct page *page) |
| 199 | { |
| 200 | __lru_cache_add(page, LRU_ACTIVE_ANON); |
| 201 | } |
| 202 | |
| 203 | static inline void lru_cache_add_file(struct page *page) |
| 204 | { |
| 205 | __lru_cache_add(page, LRU_INACTIVE_FILE); |
| 206 | } |
| 207 | |
| 208 | static inline void lru_cache_add_active_file(struct page *page) |
| 209 | { |
| 210 | __lru_cache_add(page, LRU_ACTIVE_FILE); |
| 211 | } |
| 212 | |
| 213 | /* linux/mm/vmscan.c */ |
| 214 | extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, |
| 215 | gfp_t gfp_mask, nodemask_t *mask); |
| 216 | extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem, |
| 217 | gfp_t gfp_mask, bool noswap, |
| 218 | unsigned int swappiness); |
| 219 | extern int __isolate_lru_page(struct page *page, int mode, int file); |
| 220 | extern unsigned long shrink_all_memory(unsigned long nr_pages); |
| 221 | extern int vm_swappiness; |
| 222 | extern int remove_mapping(struct address_space *mapping, struct page *page); |
| 223 | extern long vm_total_pages; |
| 224 | |
| 225 | #ifdef CONFIG_NUMA |
| 226 | extern int zone_reclaim_mode; |
| 227 | extern int sysctl_min_unmapped_ratio; |
| 228 | extern int sysctl_min_slab_ratio; |
| 229 | extern int zone_reclaim(struct zone *, gfp_t, unsigned int); |
| 230 | #else |
| 231 | #define zone_reclaim_mode 0 |
| 232 | static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order) |
| 233 | { |
| 234 | return 0; |
| 235 | } |
| 236 | #endif |
| 237 | |
| 238 | #ifdef CONFIG_UNEVICTABLE_LRU |
| 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 | #else |
| 248 | static inline int page_evictable(struct page *page, |
| 249 | struct vm_area_struct *vma) |
| 250 | { |
| 251 | return 1; |
| 252 | } |
| 253 | |
| 254 | static inline void scan_mapping_unevictable_pages(struct address_space *mapping) |
| 255 | { |
| 256 | } |
| 257 | |
| 258 | static inline int scan_unevictable_register_node(struct node *node) |
| 259 | { |
| 260 | return 0; |
| 261 | } |
| 262 | |
| 263 | static inline void scan_unevictable_unregister_node(struct node *node) { } |
| 264 | #endif |
| 265 | |
| 266 | extern int kswapd_run(int nid); |
| 267 | |
| 268 | #ifdef CONFIG_MMU |
| 269 | /* linux/mm/shmem.c */ |
| 270 | extern int shmem_unuse(swp_entry_t entry, struct page *page); |
| 271 | #endif /* CONFIG_MMU */ |
| 272 | |
| 273 | extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *); |
| 274 | |
| 275 | #ifdef CONFIG_SWAP |
| 276 | /* linux/mm/page_io.c */ |
| 277 | extern int swap_readpage(struct file *, struct page *); |
| 278 | extern int swap_writepage(struct page *page, struct writeback_control *wbc); |
| 279 | extern void end_swap_bio_read(struct bio *bio, int err); |
| 280 | |
| 281 | /* linux/mm/swap_state.c */ |
| 282 | extern struct address_space swapper_space; |
| 283 | #define total_swapcache_pages swapper_space.nrpages |
| 284 | extern void show_swap_cache_info(void); |
| 285 | extern int add_to_swap(struct page *); |
| 286 | extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t); |
| 287 | extern void __delete_from_swap_cache(struct page *); |
| 288 | extern void delete_from_swap_cache(struct page *); |
| 289 | extern void free_page_and_swap_cache(struct page *); |
| 290 | extern void free_pages_and_swap_cache(struct page **, int); |
| 291 | extern struct page *lookup_swap_cache(swp_entry_t); |
| 292 | extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, |
| 293 | struct vm_area_struct *vma, unsigned long addr); |
| 294 | extern struct page *swapin_readahead(swp_entry_t, gfp_t, |
| 295 | struct vm_area_struct *vma, unsigned long addr); |
| 296 | |
| 297 | /* linux/mm/swapfile.c */ |
| 298 | extern long nr_swap_pages; |
| 299 | extern long total_swap_pages; |
| 300 | extern void si_swapinfo(struct sysinfo *); |
| 301 | extern swp_entry_t get_swap_page(void); |
| 302 | extern swp_entry_t get_swap_page_of_type(int); |
| 303 | extern int swap_duplicate(swp_entry_t); |
| 304 | extern int valid_swaphandles(swp_entry_t, unsigned long *); |
| 305 | extern void swap_free(swp_entry_t); |
| 306 | extern int free_swap_and_cache(swp_entry_t); |
| 307 | extern int swap_type_of(dev_t, sector_t, struct block_device **); |
| 308 | extern unsigned int count_swap_pages(int, int); |
| 309 | extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t); |
| 310 | extern sector_t swapdev_block(int, pgoff_t); |
| 311 | extern struct swap_info_struct *get_swap_info_struct(unsigned); |
| 312 | extern int reuse_swap_page(struct page *); |
| 313 | extern int try_to_free_swap(struct page *); |
| 314 | struct backing_dev_info; |
| 315 | |
| 316 | /* linux/mm/thrash.c */ |
| 317 | extern struct mm_struct * swap_token_mm; |
| 318 | extern void grab_swap_token(void); |
| 319 | extern void __put_swap_token(struct mm_struct *); |
| 320 | |
| 321 | static inline int has_swap_token(struct mm_struct *mm) |
| 322 | { |
| 323 | return (mm == swap_token_mm); |
| 324 | } |
| 325 | |
| 326 | static inline void put_swap_token(struct mm_struct *mm) |
| 327 | { |
| 328 | if (has_swap_token(mm)) |
| 329 | __put_swap_token(mm); |
| 330 | } |
| 331 | |
| 332 | static inline void disable_swap_token(void) |
| 333 | { |
| 334 | put_swap_token(swap_token_mm); |
| 335 | } |
| 336 | |
| 337 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
| 338 | extern void mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent); |
| 339 | #else |
| 340 | static inline void |
| 341 | mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent) |
| 342 | { |
| 343 | } |
| 344 | #endif |
| 345 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP |
| 346 | extern void mem_cgroup_uncharge_swap(swp_entry_t ent); |
| 347 | #else |
| 348 | static inline void mem_cgroup_uncharge_swap(swp_entry_t ent) |
| 349 | { |
| 350 | } |
| 351 | #endif |
| 352 | |
| 353 | #else /* CONFIG_SWAP */ |
| 354 | |
| 355 | #define nr_swap_pages 0L |
| 356 | #define total_swap_pages 0L |
| 357 | #define total_swapcache_pages 0UL |
| 358 | |
| 359 | #define si_swapinfo(val) \ |
| 360 | do { (val)->freeswap = (val)->totalswap = 0; } while (0) |
| 361 | /* only sparc can not include linux/pagemap.h in this file |
| 362 | * so leave page_cache_release and release_pages undeclared... */ |
| 363 | #define free_page_and_swap_cache(page) \ |
| 364 | page_cache_release(page) |
| 365 | #define free_pages_and_swap_cache(pages, nr) \ |
| 366 | release_pages((pages), (nr), 0); |
| 367 | |
| 368 | static inline void show_swap_cache_info(void) |
| 369 | { |
| 370 | } |
| 371 | |
| 372 | #define free_swap_and_cache(swp) is_migration_entry(swp) |
| 373 | #define swap_duplicate(swp) is_migration_entry(swp) |
| 374 | |
| 375 | static inline void swap_free(swp_entry_t swp) |
| 376 | { |
| 377 | } |
| 378 | |
| 379 | static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, |
| 380 | struct vm_area_struct *vma, unsigned long addr) |
| 381 | { |
| 382 | return NULL; |
| 383 | } |
| 384 | |
| 385 | static inline int swap_writepage(struct page *p, struct writeback_control *wbc) |
| 386 | { |
| 387 | return 0; |
| 388 | } |
| 389 | |
| 390 | static inline struct page *lookup_swap_cache(swp_entry_t swp) |
| 391 | { |
| 392 | return NULL; |
| 393 | } |
| 394 | |
| 395 | static inline int add_to_swap(struct page *page) |
| 396 | { |
| 397 | return 0; |
| 398 | } |
| 399 | |
| 400 | static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, |
| 401 | gfp_t gfp_mask) |
| 402 | { |
| 403 | return -1; |
| 404 | } |
| 405 | |
| 406 | static inline void __delete_from_swap_cache(struct page *page) |
| 407 | { |
| 408 | } |
| 409 | |
| 410 | static inline void delete_from_swap_cache(struct page *page) |
| 411 | { |
| 412 | } |
| 413 | |
| 414 | #define reuse_swap_page(page) (page_mapcount(page) == 1) |
| 415 | |
| 416 | static inline int try_to_free_swap(struct page *page) |
| 417 | { |
| 418 | return 0; |
| 419 | } |
| 420 | |
| 421 | static inline swp_entry_t get_swap_page(void) |
| 422 | { |
| 423 | swp_entry_t entry; |
| 424 | entry.val = 0; |
| 425 | return entry; |
| 426 | } |
| 427 | |
| 428 | /* linux/mm/thrash.c */ |
| 429 | #define put_swap_token(x) do { } while(0) |
| 430 | #define grab_swap_token() do { } while(0) |
| 431 | #define has_swap_token(x) 0 |
| 432 | #define disable_swap_token() do { } while(0) |
| 433 | |
| 434 | static inline int mem_cgroup_cache_charge_swapin(struct page *page, |
| 435 | struct mm_struct *mm, gfp_t mask, bool locked) |
| 436 | { |
| 437 | return 0; |
| 438 | } |
| 439 | |
| 440 | #endif /* CONFIG_SWAP */ |
| 441 | #endif /* __KERNEL__*/ |
| 442 | #endif /* _LINUX_SWAP_H */ |