Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | #ifndef _LINUX_SWAP_H |
| 2 | #define _LINUX_SWAP_H |
| 3 | |
| 4 | #include <linux/config.h> |
| 5 | #include <linux/spinlock.h> |
| 6 | #include <linux/linkage.h> |
| 7 | #include <linux/mmzone.h> |
| 8 | #include <linux/list.h> |
| 9 | #include <linux/sched.h> |
| 10 | #include <asm/atomic.h> |
| 11 | #include <asm/page.h> |
| 12 | |
| 13 | #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */ |
| 14 | #define SWAP_FLAG_PRIO_MASK 0x7fff |
| 15 | #define SWAP_FLAG_PRIO_SHIFT 0 |
| 16 | |
| 17 | static inline int current_is_kswapd(void) |
| 18 | { |
| 19 | return current->flags & PF_KSWAPD; |
| 20 | } |
| 21 | |
| 22 | /* |
| 23 | * MAX_SWAPFILES defines the maximum number of swaptypes: things which can |
| 24 | * be swapped to. The swap type and the offset into that swap type are |
| 25 | * encoded into pte's and into pgoff_t's in the swapcache. Using five bits |
| 26 | * for the type means that the maximum number of swapcache pages is 27 bits |
| 27 | * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs |
| 28 | * the type/offset into the pte as 5/27 as well. |
| 29 | */ |
| 30 | #define MAX_SWAPFILES_SHIFT 5 |
| 31 | #define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT) |
| 32 | |
| 33 | /* |
| 34 | * Magic header for a swap area. The first part of the union is |
| 35 | * what the swap magic looks like for the old (limited to 128MB) |
| 36 | * swap area format, the second part of the union adds - in the |
| 37 | * old reserved area - some extra information. Note that the first |
| 38 | * kilobyte is reserved for boot loader or disk label stuff... |
| 39 | * |
| 40 | * Having the magic at the end of the PAGE_SIZE makes detecting swap |
| 41 | * areas somewhat tricky on machines that support multiple page sizes. |
| 42 | * For 2.5 we'll probably want to move the magic to just beyond the |
| 43 | * bootbits... |
| 44 | */ |
| 45 | union swap_header { |
| 46 | struct { |
| 47 | char reserved[PAGE_SIZE - 10]; |
| 48 | char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */ |
| 49 | } magic; |
| 50 | struct { |
| 51 | char bootbits[1024]; /* Space for disklabel etc. */ |
| 52 | unsigned int version; |
| 53 | unsigned int last_page; |
| 54 | unsigned int nr_badpages; |
| 55 | unsigned int padding[125]; |
| 56 | unsigned int badpages[1]; |
| 57 | } info; |
| 58 | }; |
| 59 | |
| 60 | /* A swap entry has to fit into a "unsigned long", as |
| 61 | * the entry is hidden in the "index" field of the |
| 62 | * swapper address space. |
| 63 | */ |
| 64 | typedef struct { |
| 65 | unsigned long val; |
| 66 | } swp_entry_t; |
| 67 | |
| 68 | /* |
| 69 | * current->reclaim_state points to one of these when a task is running |
| 70 | * memory reclaim |
| 71 | */ |
| 72 | struct reclaim_state { |
| 73 | unsigned long reclaimed_slab; |
| 74 | }; |
| 75 | |
| 76 | #ifdef __KERNEL__ |
| 77 | |
| 78 | struct address_space; |
| 79 | struct sysinfo; |
| 80 | struct writeback_control; |
| 81 | struct zone; |
| 82 | |
| 83 | /* |
| 84 | * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of |
| 85 | * disk blocks. A list of swap extents maps the entire swapfile. (Where the |
| 86 | * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart |
| 87 | * from setup, they're handled identically. |
| 88 | * |
| 89 | * We always assume that blocks are of size PAGE_SIZE. |
| 90 | */ |
| 91 | struct swap_extent { |
| 92 | struct list_head list; |
| 93 | pgoff_t start_page; |
| 94 | pgoff_t nr_pages; |
| 95 | sector_t start_block; |
| 96 | }; |
| 97 | |
| 98 | /* |
| 99 | * Max bad pages in the new format.. |
| 100 | */ |
| 101 | #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x) |
| 102 | #define MAX_SWAP_BADPAGES \ |
| 103 | ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int)) |
| 104 | |
| 105 | enum { |
| 106 | SWP_USED = (1 << 0), /* is slot in swap_info[] used? */ |
| 107 | SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */ |
| 108 | SWP_ACTIVE = (SWP_USED | SWP_WRITEOK), |
| 109 | }; |
| 110 | |
| 111 | #define SWAP_CLUSTER_MAX 32 |
| 112 | |
| 113 | #define SWAP_MAP_MAX 0x7fff |
| 114 | #define SWAP_MAP_BAD 0x8000 |
| 115 | |
| 116 | /* |
| 117 | * The in-memory structure used to track swap areas. |
| 118 | * extent_list.prev points at the lowest-index extent. That list is |
| 119 | * sorted. |
| 120 | */ |
| 121 | struct swap_info_struct { |
| 122 | unsigned int flags; |
| 123 | spinlock_t sdev_lock; |
| 124 | struct file *swap_file; |
| 125 | struct block_device *bdev; |
| 126 | struct list_head extent_list; |
| 127 | int nr_extents; |
| 128 | struct swap_extent *curr_swap_extent; |
| 129 | unsigned old_block_size; |
| 130 | unsigned short * swap_map; |
| 131 | unsigned int lowest_bit; |
| 132 | unsigned int highest_bit; |
| 133 | unsigned int cluster_next; |
| 134 | unsigned int cluster_nr; |
| 135 | int prio; /* swap priority */ |
| 136 | int pages; |
| 137 | unsigned long max; |
| 138 | unsigned long inuse_pages; |
| 139 | int next; /* next entry on swap list */ |
| 140 | }; |
| 141 | |
| 142 | struct swap_list_t { |
| 143 | int head; /* head of priority-ordered swapfile list */ |
| 144 | int next; /* swapfile to be used next */ |
| 145 | }; |
| 146 | |
| 147 | /* Swap 50% full? Release swapcache more aggressively.. */ |
| 148 | #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages) |
| 149 | |
| 150 | /* linux/mm/oom_kill.c */ |
| 151 | extern void out_of_memory(unsigned int __nocast gfp_mask); |
| 152 | |
| 153 | /* linux/mm/memory.c */ |
| 154 | extern void swapin_readahead(swp_entry_t, unsigned long, struct vm_area_struct *); |
| 155 | |
| 156 | /* linux/mm/page_alloc.c */ |
| 157 | extern unsigned long totalram_pages; |
| 158 | extern unsigned long totalhigh_pages; |
| 159 | extern long nr_swap_pages; |
| 160 | extern unsigned int nr_free_pages(void); |
| 161 | extern unsigned int nr_free_pages_pgdat(pg_data_t *pgdat); |
| 162 | extern unsigned int nr_free_buffer_pages(void); |
| 163 | extern unsigned int nr_free_pagecache_pages(void); |
| 164 | |
| 165 | /* linux/mm/swap.c */ |
| 166 | extern void FASTCALL(lru_cache_add(struct page *)); |
| 167 | extern void FASTCALL(lru_cache_add_active(struct page *)); |
| 168 | extern void FASTCALL(activate_page(struct page *)); |
| 169 | extern void FASTCALL(mark_page_accessed(struct page *)); |
| 170 | extern void lru_add_drain(void); |
| 171 | extern int rotate_reclaimable_page(struct page *page); |
| 172 | extern void swap_setup(void); |
| 173 | |
| 174 | /* linux/mm/vmscan.c */ |
Darren Hart | 1ad539b | 2005-06-21 17:14:53 -0700 | [diff] [blame] | 175 | extern int try_to_free_pages(struct zone **, unsigned int); |
Martin Hicks | 753ee72 | 2005-06-21 17:14:41 -0700 | [diff] [blame] | 176 | extern int zone_reclaim(struct zone *, unsigned int, unsigned int); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | extern int shrink_all_memory(int); |
| 178 | extern int vm_swappiness; |
| 179 | |
| 180 | #ifdef CONFIG_MMU |
| 181 | /* linux/mm/shmem.c */ |
| 182 | extern int shmem_unuse(swp_entry_t entry, struct page *page); |
| 183 | #endif /* CONFIG_MMU */ |
| 184 | |
| 185 | extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *); |
| 186 | |
| 187 | #ifdef CONFIG_SWAP |
| 188 | /* linux/mm/page_io.c */ |
| 189 | extern int swap_readpage(struct file *, struct page *); |
| 190 | extern int swap_writepage(struct page *page, struct writeback_control *wbc); |
| 191 | extern int rw_swap_page_sync(int, swp_entry_t, struct page *); |
| 192 | |
| 193 | /* linux/mm/swap_state.c */ |
| 194 | extern struct address_space swapper_space; |
| 195 | #define total_swapcache_pages swapper_space.nrpages |
| 196 | extern void show_swap_cache_info(void); |
| 197 | extern int add_to_swap(struct page *); |
| 198 | extern void __delete_from_swap_cache(struct page *); |
| 199 | extern void delete_from_swap_cache(struct page *); |
| 200 | extern int move_to_swap_cache(struct page *, swp_entry_t); |
| 201 | extern int move_from_swap_cache(struct page *, unsigned long, |
| 202 | struct address_space *); |
| 203 | extern void free_page_and_swap_cache(struct page *); |
| 204 | extern void free_pages_and_swap_cache(struct page **, int); |
| 205 | extern struct page * lookup_swap_cache(swp_entry_t); |
| 206 | extern struct page * read_swap_cache_async(swp_entry_t, struct vm_area_struct *vma, |
| 207 | unsigned long addr); |
| 208 | /* linux/mm/swapfile.c */ |
| 209 | extern long total_swap_pages; |
| 210 | extern unsigned int nr_swapfiles; |
| 211 | extern struct swap_info_struct swap_info[]; |
| 212 | extern void si_swapinfo(struct sysinfo *); |
| 213 | extern swp_entry_t get_swap_page(void); |
| 214 | extern int swap_duplicate(swp_entry_t); |
| 215 | extern int valid_swaphandles(swp_entry_t, unsigned long *); |
| 216 | extern void swap_free(swp_entry_t); |
| 217 | extern void free_swap_and_cache(swp_entry_t); |
| 218 | extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t); |
| 219 | extern struct swap_info_struct *get_swap_info_struct(unsigned); |
| 220 | extern int can_share_swap_page(struct page *); |
| 221 | extern int remove_exclusive_swap_page(struct page *); |
| 222 | struct backing_dev_info; |
| 223 | |
| 224 | extern struct swap_list_t swap_list; |
| 225 | extern spinlock_t swaplock; |
| 226 | |
| 227 | #define swap_list_lock() spin_lock(&swaplock) |
| 228 | #define swap_list_unlock() spin_unlock(&swaplock) |
| 229 | #define swap_device_lock(p) spin_lock(&p->sdev_lock) |
| 230 | #define swap_device_unlock(p) spin_unlock(&p->sdev_lock) |
| 231 | |
| 232 | /* linux/mm/thrash.c */ |
| 233 | extern struct mm_struct * swap_token_mm; |
| 234 | extern unsigned long swap_token_default_timeout; |
| 235 | extern void grab_swap_token(void); |
| 236 | extern void __put_swap_token(struct mm_struct *); |
| 237 | |
| 238 | static inline int has_swap_token(struct mm_struct *mm) |
| 239 | { |
| 240 | return (mm == swap_token_mm); |
| 241 | } |
| 242 | |
| 243 | static inline void put_swap_token(struct mm_struct *mm) |
| 244 | { |
| 245 | if (has_swap_token(mm)) |
| 246 | __put_swap_token(mm); |
| 247 | } |
| 248 | |
| 249 | #else /* CONFIG_SWAP */ |
| 250 | |
| 251 | #define total_swap_pages 0 |
| 252 | #define total_swapcache_pages 0UL |
| 253 | |
| 254 | #define si_swapinfo(val) \ |
| 255 | do { (val)->freeswap = (val)->totalswap = 0; } while (0) |
| 256 | #define free_page_and_swap_cache(page) \ |
| 257 | page_cache_release(page) |
| 258 | #define free_pages_and_swap_cache(pages, nr) \ |
| 259 | release_pages((pages), (nr), 0); |
| 260 | |
| 261 | #define show_swap_cache_info() /*NOTHING*/ |
| 262 | #define free_swap_and_cache(swp) /*NOTHING*/ |
| 263 | #define swap_duplicate(swp) /*NOTHING*/ |
| 264 | #define swap_free(swp) /*NOTHING*/ |
| 265 | #define read_swap_cache_async(swp,vma,addr) NULL |
| 266 | #define lookup_swap_cache(swp) NULL |
| 267 | #define valid_swaphandles(swp, off) 0 |
| 268 | #define can_share_swap_page(p) 0 |
| 269 | #define move_to_swap_cache(p, swp) 1 |
| 270 | #define move_from_swap_cache(p, i, m) 1 |
| 271 | #define __delete_from_swap_cache(p) /*NOTHING*/ |
| 272 | #define delete_from_swap_cache(p) /*NOTHING*/ |
| 273 | #define swap_token_default_timeout 0 |
| 274 | |
| 275 | static inline int remove_exclusive_swap_page(struct page *p) |
| 276 | { |
| 277 | return 0; |
| 278 | } |
| 279 | |
| 280 | static inline swp_entry_t get_swap_page(void) |
| 281 | { |
| 282 | swp_entry_t entry; |
| 283 | entry.val = 0; |
| 284 | return entry; |
| 285 | } |
| 286 | |
| 287 | /* linux/mm/thrash.c */ |
| 288 | #define put_swap_token(x) do { } while(0) |
| 289 | #define grab_swap_token() do { } while(0) |
| 290 | #define has_swap_token(x) 0 |
| 291 | |
| 292 | #endif /* CONFIG_SWAP */ |
| 293 | #endif /* __KERNEL__*/ |
| 294 | #endif /* _LINUX_SWAP_H */ |