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/memory.c */ 162 extern void swapin_readahead(swp_entry_t, unsigned long, struct vm_area_struct *); 163 164 /* linux/mm/page_alloc.c */ 165 extern unsigned long totalram_pages; 166 extern unsigned long totalreserve_pages; 167 extern long nr_swap_pages; 168 extern unsigned int nr_free_buffer_pages(void); 169 extern unsigned int nr_free_pagecache_pages(void); 170 171 /* Definition of global_page_state not available yet */ 172 #define nr_free_pages() global_page_state(NR_FREE_PAGES) 173 174 175 /* linux/mm/swap.c */ 176 extern void FASTCALL(lru_cache_add(struct page *)); 177 extern void FASTCALL(lru_cache_add_active(struct page *)); 178 extern void FASTCALL(activate_page(struct page *)); 179 extern void FASTCALL(mark_page_accessed(struct page *)); 180 extern void lru_add_drain(void); 181 extern int lru_add_drain_all(void); 182 extern int rotate_reclaimable_page(struct page *page); 183 extern void swap_setup(void); 184 185 /* linux/mm/vmscan.c */ 186 extern unsigned long try_to_free_pages(struct zone **zones, int order, 187 gfp_t gfp_mask); 188 extern unsigned long shrink_all_memory(unsigned long nr_pages); 189 extern int vm_swappiness; 190 extern int remove_mapping(struct address_space *mapping, struct page *page); 191 extern long vm_total_pages; 192 193 #ifdef CONFIG_NUMA 194 extern int zone_reclaim_mode; 195 extern int sysctl_min_unmapped_ratio; 196 extern int sysctl_min_slab_ratio; 197 extern int zone_reclaim(struct zone *, gfp_t, unsigned int); 198 #else 199 #define zone_reclaim_mode 0 200 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order) 201 { 202 return 0; 203 } 204 #endif 205 206 extern int kswapd_run(int nid); 207 208 #ifdef CONFIG_MMU 209 /* linux/mm/shmem.c */ 210 extern int shmem_unuse(swp_entry_t entry, struct page *page); 211 #endif /* CONFIG_MMU */ 212 213 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *); 214 215 #ifdef CONFIG_SWAP 216 /* linux/mm/page_io.c */ 217 extern int swap_readpage(struct file *, struct page *); 218 extern int swap_writepage(struct page *page, struct writeback_control *wbc); 219 extern void end_swap_bio_read(struct bio *bio, int err); 220 221 /* linux/mm/swap_state.c */ 222 extern struct address_space swapper_space; 223 #define total_swapcache_pages swapper_space.nrpages 224 extern void show_swap_cache_info(void); 225 extern int add_to_swap(struct page *, gfp_t); 226 extern void __delete_from_swap_cache(struct page *); 227 extern void delete_from_swap_cache(struct page *); 228 extern int move_to_swap_cache(struct page *, swp_entry_t); 229 extern int move_from_swap_cache(struct page *, unsigned long, 230 struct address_space *); 231 extern void free_page_and_swap_cache(struct page *); 232 extern void free_pages_and_swap_cache(struct page **, int); 233 extern struct page * lookup_swap_cache(swp_entry_t); 234 extern struct page * read_swap_cache_async(swp_entry_t, struct vm_area_struct *vma, 235 unsigned long addr); 236 /* linux/mm/swapfile.c */ 237 extern long total_swap_pages; 238 extern unsigned int nr_swapfiles; 239 extern void si_swapinfo(struct sysinfo *); 240 extern swp_entry_t get_swap_page(void); 241 extern swp_entry_t get_swap_page_of_type(int); 242 extern int swap_duplicate(swp_entry_t); 243 extern int valid_swaphandles(swp_entry_t, unsigned long *); 244 extern void swap_free(swp_entry_t); 245 extern void free_swap_and_cache(swp_entry_t); 246 extern int swap_type_of(dev_t, sector_t, struct block_device **); 247 extern unsigned int count_swap_pages(int, int); 248 extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t); 249 extern sector_t swapdev_block(int, pgoff_t); 250 extern struct swap_info_struct *get_swap_info_struct(unsigned); 251 extern int can_share_swap_page(struct page *); 252 extern int remove_exclusive_swap_page(struct page *); 253 struct backing_dev_info; 254 255 extern spinlock_t swap_lock; 256 257 /* linux/mm/thrash.c */ 258 extern struct mm_struct * swap_token_mm; 259 extern void grab_swap_token(void); 260 extern void __put_swap_token(struct mm_struct *); 261 262 static inline int has_swap_token(struct mm_struct *mm) 263 { 264 return (mm == swap_token_mm); 265 } 266 267 static inline void put_swap_token(struct mm_struct *mm) 268 { 269 if (has_swap_token(mm)) 270 __put_swap_token(mm); 271 } 272 273 static inline void disable_swap_token(void) 274 { 275 put_swap_token(swap_token_mm); 276 } 277 278 #else /* CONFIG_SWAP */ 279 280 #define total_swap_pages 0 281 #define total_swapcache_pages 0UL 282 283 #define si_swapinfo(val) \ 284 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 285 /* only sparc can not include linux/pagemap.h in this file 286 * so leave page_cache_release and release_pages undeclared... */ 287 #define free_page_and_swap_cache(page) \ 288 page_cache_release(page) 289 #define free_pages_and_swap_cache(pages, nr) \ 290 release_pages((pages), (nr), 0); 291 292 static inline void show_swap_cache_info(void) 293 { 294 } 295 296 static inline void free_swap_and_cache(swp_entry_t swp) 297 { 298 } 299 300 static inline int swap_duplicate(swp_entry_t swp) 301 { 302 return 0; 303 } 304 305 static inline void swap_free(swp_entry_t swp) 306 { 307 } 308 309 static inline struct page *read_swap_cache_async(swp_entry_t swp, 310 struct vm_area_struct *vma, unsigned long addr) 311 { 312 return NULL; 313 } 314 315 static inline struct page *lookup_swap_cache(swp_entry_t swp) 316 { 317 return NULL; 318 } 319 320 static inline int valid_swaphandles(swp_entry_t entry, unsigned long *offset) 321 { 322 return 0; 323 } 324 325 #define can_share_swap_page(p) (page_mapcount(p) == 1) 326 327 static inline int move_to_swap_cache(struct page *page, swp_entry_t entry) 328 { 329 return 1; 330 } 331 332 static inline int move_from_swap_cache(struct page *page, unsigned long index, 333 struct address_space *mapping) 334 { 335 return 1; 336 } 337 338 static inline void __delete_from_swap_cache(struct page *page) 339 { 340 } 341 342 static inline void delete_from_swap_cache(struct page *page) 343 { 344 } 345 346 #define swap_token_default_timeout 0 347 348 static inline int remove_exclusive_swap_page(struct page *p) 349 { 350 return 0; 351 } 352 353 static inline swp_entry_t get_swap_page(void) 354 { 355 swp_entry_t entry; 356 entry.val = 0; 357 return entry; 358 } 359 360 /* linux/mm/thrash.c */ 361 #define put_swap_token(x) do { } while(0) 362 #define grab_swap_token() do { } while(0) 363 #define has_swap_token(x) 0 364 #define disable_swap_token() do { } while(0) 365 366 #endif /* CONFIG_SWAP */ 367 #endif /* __KERNEL__*/ 368 #endif /* _LINUX_SWAP_H */ 369