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