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/sched.h> 9 10 #include <asm/atomic.h> 11 #include <asm/page.h> 12 13 struct notifier_block; 14 15 struct bio; 16 17 #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */ 18 #define SWAP_FLAG_PRIO_MASK 0x7fff 19 #define SWAP_FLAG_PRIO_SHIFT 0 20 21 static inline int current_is_kswapd(void) 22 { 23 return current->flags & PF_KSWAPD; 24 } 25 26 /* 27 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can 28 * be swapped to. The swap type and the offset into that swap type are 29 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits 30 * for the type means that the maximum number of swapcache pages is 27 bits 31 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs 32 * the type/offset into the pte as 5/27 as well. 33 */ 34 #define MAX_SWAPFILES_SHIFT 5 35 #ifndef CONFIG_MIGRATION 36 #define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT) 37 #else 38 /* Use last two entries for page migration swap entries */ 39 #define MAX_SWAPFILES ((1 << MAX_SWAPFILES_SHIFT)-2) 40 #define SWP_MIGRATION_READ MAX_SWAPFILES 41 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + 1) 42 #endif 43 44 /* 45 * Magic header for a swap area. The first part of the union is 46 * what the swap magic looks like for the old (limited to 128MB) 47 * swap area format, the second part of the union adds - in the 48 * old reserved area - some extra information. Note that the first 49 * kilobyte is reserved for boot loader or disk label stuff... 50 * 51 * Having the magic at the end of the PAGE_SIZE makes detecting swap 52 * areas somewhat tricky on machines that support multiple page sizes. 53 * For 2.5 we'll probably want to move the magic to just beyond the 54 * bootbits... 55 */ 56 union swap_header { 57 struct { 58 char reserved[PAGE_SIZE - 10]; 59 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */ 60 } magic; 61 struct { 62 char bootbits[1024]; /* Space for disklabel etc. */ 63 __u32 version; 64 __u32 last_page; 65 __u32 nr_badpages; 66 unsigned char sws_uuid[16]; 67 unsigned char sws_volume[16]; 68 __u32 padding[117]; 69 __u32 badpages[1]; 70 } info; 71 }; 72 73 /* A swap entry has to fit into a "unsigned long", as 74 * the entry is hidden in the "index" field of the 75 * swapper address space. 76 */ 77 typedef struct { 78 unsigned long val; 79 } swp_entry_t; 80 81 /* 82 * current->reclaim_state points to one of these when a task is running 83 * memory reclaim 84 */ 85 struct reclaim_state { 86 unsigned long reclaimed_slab; 87 }; 88 89 #ifdef __KERNEL__ 90 91 struct address_space; 92 struct sysinfo; 93 struct writeback_control; 94 struct zone; 95 96 /* 97 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of 98 * disk blocks. A list of swap extents maps the entire swapfile. (Where the 99 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart 100 * from setup, they're handled identically. 101 * 102 * We always assume that blocks are of size PAGE_SIZE. 103 */ 104 struct swap_extent { 105 struct list_head list; 106 pgoff_t start_page; 107 pgoff_t nr_pages; 108 sector_t start_block; 109 }; 110 111 /* 112 * Max bad pages in the new format.. 113 */ 114 #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x) 115 #define MAX_SWAP_BADPAGES \ 116 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int)) 117 118 enum { 119 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */ 120 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */ 121 SWP_ACTIVE = (SWP_USED | SWP_WRITEOK), 122 /* add others here before... */ 123 SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */ 124 }; 125 126 #define SWAP_CLUSTER_MAX 32 127 128 #define SWAP_MAP_MAX 0x7fff 129 #define SWAP_MAP_BAD 0x8000 130 131 /* 132 * The in-memory structure used to track swap areas. 133 */ 134 struct swap_info_struct { 135 unsigned int flags; 136 int prio; /* swap priority */ 137 struct file *swap_file; 138 struct block_device *bdev; 139 struct list_head extent_list; 140 struct swap_extent *curr_swap_extent; 141 unsigned old_block_size; 142 unsigned short * swap_map; 143 unsigned int lowest_bit; 144 unsigned int highest_bit; 145 unsigned int cluster_next; 146 unsigned int cluster_nr; 147 unsigned int pages; 148 unsigned int max; 149 unsigned int inuse_pages; 150 int next; /* next entry on swap list */ 151 }; 152 153 struct swap_list_t { 154 int head; /* head of priority-ordered swapfile list */ 155 int next; /* swapfile to be used next */ 156 }; 157 158 /* Swap 50% full? Release swapcache more aggressively.. */ 159 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages) 160 161 /* linux/mm/oom_kill.c */ 162 extern void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order); 163 extern int register_oom_notifier(struct notifier_block *nb); 164 extern int unregister_oom_notifier(struct notifier_block *nb); 165 166 /* linux/mm/memory.c */ 167 extern void swapin_readahead(swp_entry_t, unsigned long, struct vm_area_struct *); 168 169 /* linux/mm/page_alloc.c */ 170 extern unsigned long totalram_pages; 171 extern unsigned long totalreserve_pages; 172 extern long nr_swap_pages; 173 extern unsigned int nr_free_buffer_pages(void); 174 extern unsigned int nr_free_pagecache_pages(void); 175 176 /* Definition of global_page_state not available yet */ 177 #define nr_free_pages() global_page_state(NR_FREE_PAGES) 178 179 180 /* linux/mm/swap.c */ 181 extern void FASTCALL(lru_cache_add(struct page *)); 182 extern void FASTCALL(lru_cache_add_active(struct page *)); 183 extern void FASTCALL(activate_page(struct page *)); 184 extern void FASTCALL(mark_page_accessed(struct page *)); 185 extern void lru_add_drain(void); 186 extern int lru_add_drain_all(void); 187 extern int rotate_reclaimable_page(struct page *page); 188 extern void swap_setup(void); 189 190 /* linux/mm/vmscan.c */ 191 extern unsigned long try_to_free_pages(struct zone **, gfp_t); 192 extern unsigned long shrink_all_memory(unsigned long nr_pages); 193 extern int vm_swappiness; 194 extern int remove_mapping(struct address_space *mapping, struct page *page); 195 extern long vm_total_pages; 196 197 #ifdef CONFIG_NUMA 198 extern int zone_reclaim_mode; 199 extern int sysctl_min_unmapped_ratio; 200 extern int sysctl_min_slab_ratio; 201 extern int zone_reclaim(struct zone *, gfp_t, unsigned int); 202 #else 203 #define zone_reclaim_mode 0 204 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order) 205 { 206 return 0; 207 } 208 #endif 209 210 extern int kswapd_run(int nid); 211 212 #ifdef CONFIG_MMU 213 /* linux/mm/shmem.c */ 214 extern int shmem_unuse(swp_entry_t entry, struct page *page); 215 #endif /* CONFIG_MMU */ 216 217 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *); 218 219 #ifdef CONFIG_SWAP 220 /* linux/mm/page_io.c */ 221 extern int swap_readpage(struct file *, struct page *); 222 extern int swap_writepage(struct page *page, struct writeback_control *wbc); 223 extern int end_swap_bio_read(struct bio *bio, unsigned int bytes_done, int err); 224 225 /* linux/mm/swap_state.c */ 226 extern struct address_space swapper_space; 227 #define total_swapcache_pages swapper_space.nrpages 228 extern void show_swap_cache_info(void); 229 extern int add_to_swap(struct page *, gfp_t); 230 extern void __delete_from_swap_cache(struct page *); 231 extern void delete_from_swap_cache(struct page *); 232 extern int move_to_swap_cache(struct page *, swp_entry_t); 233 extern int move_from_swap_cache(struct page *, unsigned long, 234 struct address_space *); 235 extern void free_page_and_swap_cache(struct page *); 236 extern void free_pages_and_swap_cache(struct page **, int); 237 extern struct page * lookup_swap_cache(swp_entry_t); 238 extern struct page * read_swap_cache_async(swp_entry_t, struct vm_area_struct *vma, 239 unsigned long addr); 240 /* linux/mm/swapfile.c */ 241 extern long total_swap_pages; 242 extern unsigned int nr_swapfiles; 243 extern void si_swapinfo(struct sysinfo *); 244 extern swp_entry_t get_swap_page(void); 245 extern swp_entry_t get_swap_page_of_type(int); 246 extern int swap_duplicate(swp_entry_t); 247 extern int valid_swaphandles(swp_entry_t, unsigned long *); 248 extern void swap_free(swp_entry_t); 249 extern void free_swap_and_cache(swp_entry_t); 250 extern int swap_type_of(dev_t, sector_t, struct block_device **); 251 extern unsigned int count_swap_pages(int, int); 252 extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t); 253 extern sector_t swapdev_block(int, pgoff_t); 254 extern struct swap_info_struct *get_swap_info_struct(unsigned); 255 extern int can_share_swap_page(struct page *); 256 extern int remove_exclusive_swap_page(struct page *); 257 struct backing_dev_info; 258 259 extern spinlock_t swap_lock; 260 261 /* linux/mm/thrash.c */ 262 extern struct mm_struct * swap_token_mm; 263 extern void grab_swap_token(void); 264 extern void __put_swap_token(struct mm_struct *); 265 266 static inline int has_swap_token(struct mm_struct *mm) 267 { 268 return (mm == swap_token_mm); 269 } 270 271 static inline void put_swap_token(struct mm_struct *mm) 272 { 273 if (has_swap_token(mm)) 274 __put_swap_token(mm); 275 } 276 277 static inline void disable_swap_token(void) 278 { 279 put_swap_token(swap_token_mm); 280 } 281 282 #else /* CONFIG_SWAP */ 283 284 #define total_swap_pages 0 285 #define total_swapcache_pages 0UL 286 287 #define si_swapinfo(val) \ 288 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 289 /* only sparc can not include linux/pagemap.h in this file 290 * so leave page_cache_release and release_pages undeclared... */ 291 #define free_page_and_swap_cache(page) \ 292 page_cache_release(page) 293 #define free_pages_and_swap_cache(pages, nr) \ 294 release_pages((pages), (nr), 0); 295 296 static inline void show_swap_cache_info(void) 297 { 298 } 299 300 static inline void free_swap_and_cache(swp_entry_t swp) 301 { 302 } 303 304 static inline int swap_duplicate(swp_entry_t swp) 305 { 306 return 0; 307 } 308 309 static inline void swap_free(swp_entry_t swp) 310 { 311 } 312 313 static inline struct page *read_swap_cache_async(swp_entry_t swp, 314 struct vm_area_struct *vma, unsigned long addr) 315 { 316 return NULL; 317 } 318 319 static inline struct page *lookup_swap_cache(swp_entry_t swp) 320 { 321 return NULL; 322 } 323 324 static inline int valid_swaphandles(swp_entry_t entry, unsigned long *offset) 325 { 326 return 0; 327 } 328 329 #define can_share_swap_page(p) (page_mapcount(p) == 1) 330 331 static inline int move_to_swap_cache(struct page *page, swp_entry_t entry) 332 { 333 return 1; 334 } 335 336 static inline int move_from_swap_cache(struct page *page, unsigned long index, 337 struct address_space *mapping) 338 { 339 return 1; 340 } 341 342 static inline void __delete_from_swap_cache(struct page *page) 343 { 344 } 345 346 static inline void delete_from_swap_cache(struct page *page) 347 { 348 } 349 350 #define swap_token_default_timeout 0 351 352 static inline int remove_exclusive_swap_page(struct page *p) 353 { 354 return 0; 355 } 356 357 static inline swp_entry_t get_swap_page(void) 358 { 359 swp_entry_t entry; 360 entry.val = 0; 361 return entry; 362 } 363 364 /* linux/mm/thrash.c */ 365 #define put_swap_token(x) do { } while(0) 366 #define grab_swap_token() do { } while(0) 367 #define has_swap_token(x) 0 368 #define disable_swap_token() do { } while(0) 369 370 #endif /* CONFIG_SWAP */ 371 #endif /* __KERNEL__*/ 372 #endif /* _LINUX_SWAP_H */ 373