include/linux/swap.h

   1 #ifndef _LINUX_SWAP_H
   2 #define _LINUX_SWAP_H
   3
   4 #include <asm/page.h>
   5
   6 #define SWAP_FLAG_PREFER        0x8000  /* set if swap priority specified */
   7 #define SWAP_FLAG_PRIO_MASK     0x7fff
   8 #define SWAP_FLAG_PRIO_SHIFT    0
   9
  10 #define MAX_SWAPFILES 8
  11
  12 union swap_header {
  13         struct
  14         {
  15                 char reserved[PAGE_SIZE - 10];
  16                 char magic[10];
  17         } magic;
  18         struct
  19         {
  20                 char         bootbits[1024];    /* Space for disklabel etc. */
  21                 unsigned int version;
  22                 unsigned int last_page;
  23                 unsigned int nr_badpages;
  24                 unsigned int padding[125];
  25                 unsigned int badpages[1];
  26         } info;
  27 };
  28
  29 #ifdef __KERNEL__
  30
  31 /*
  32  * Max bad pages in the new format..
  33  */
  34 #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
  35 #define MAX_SWAP_BADPAGES \
  36         ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
  37
  38 #undef DEBUG_SWAP
  39
  40 #include <asm/atomic.h>
  41
  42 #define SWP_USED        1
  43 #define SWP_WRITEOK     3
  44
  45 #define SWAP_CLUSTER_MAX 32
  46
  47 #define SWAP_MAP_MAX    0x7fff
  48 #define SWAP_MAP_BAD    0x8000
  49
  50 struct swap_info_struct {
  51         unsigned int flags;
  52         kdev_t swap_device;
  53         struct dentry * swap_file;
  54         unsigned short * swap_map;
  55         unsigned char * swap_lockmap;
  56         unsigned int lowest_bit;
  57         unsigned int highest_bit;
  58         unsigned int cluster_next;
  59         unsigned int cluster_nr;
  60         int prio;                       /* swap priority */
  61         int pages;
  62         unsigned long max;
  63         int next;                       /* next entry on swap list */
  64 };
  65
  66 extern int nr_swap_pages;
  67 extern int nr_free_pages;
  68 extern atomic_t nr_async_pages;
  69 extern struct inode swapper_inode;
  70 extern unsigned long page_cache_size;
  71 extern int buffermem;
  72
  73 /* Incomplete types for prototype declarations: */
  74 struct task_struct;
  75 struct vm_area_struct;
  76 struct sysinfo;
  77
  78 /* linux/ipc/shm.c */
  79 extern int shm_swap (int, int);
  80
  81 /* linux/mm/swap.c */
  82 extern void swap_setup (void);
  83
  84 /* linux/mm/vmscan.c */
  85 extern int try_to_free_pages(unsigned int gfp_mask);
  86
  87 /* linux/mm/page_io.c */
  88 extern void rw_swap_page(int, unsigned long, char *, int);
  89 extern void rw_swap_page_nocache(int, unsigned long, char *);
  90 extern void rw_swap_page_nolock(int, unsigned long, char *, int);
  91 extern void swap_after_unlock_page (unsigned long entry);
  92
  93 /* linux/mm/page_alloc.c */
  94 extern void swap_in(struct task_struct *, struct vm_area_struct *,
  95                     pte_t *, unsigned long, int);
  96
  97
  98 /* linux/mm/swap_state.c */
  99 extern void show_swap_cache_info(void);
 100 extern int add_to_swap_cache(struct page *, unsigned long);
 101 extern int swap_duplicate(unsigned long);
 102 extern int swap_check_entry(unsigned long);
 103 struct page * lookup_swap_cache(unsigned long);
 104 extern struct page * read_swap_cache_async(unsigned long, int);
 105 #define read_swap_cache(entry) read_swap_cache_async(entry, 1);
 106 extern int FASTCALL(swap_count(unsigned long));
 107 /*
 108  * Make these inline later once they are working properly.
 109  */
 110 extern void delete_from_swap_cache(struct page *page);
 111 extern void free_page_and_swap_cache(unsigned long addr);
 112
 113 /* linux/mm/swapfile.c */
 114 extern unsigned int nr_swapfiles;
 115 extern struct swap_info_struct swap_info[];
 116 void si_swapinfo(struct sysinfo *);
 117 unsigned long get_swap_page(void);
 118 extern void FASTCALL(swap_free(unsigned long));
 119 struct swap_list_t {
 120         int head;       /* head of priority-ordered swapfile list */
 121         int next;       /* swapfile to be used next */
 122 };
 123 extern struct swap_list_t swap_list;
 124 asmlinkage int sys_swapoff(const char *);
 125 asmlinkage int sys_swapon(const char *, int);
 126
 127 /*
 128  * vm_ops not present page codes for shared memory.
 129  *
 130  * Will go away eventually..
 131  */
 132 #define SHM_SWP_TYPE 0x20
 133
 134 /*
 135  * swap cache stuff (in linux/mm/swap_state.c)
 136  */
 137
 138 #define SWAP_CACHE_INFO
 139
 140 #ifdef SWAP_CACHE_INFO
 141 extern unsigned long swap_cache_add_total;
 142 extern unsigned long swap_cache_del_total;
 143 extern unsigned long swap_cache_find_total;
 144 extern unsigned long swap_cache_find_success;
 145 #endif
 146
 147 extern inline unsigned long in_swap_cache(struct page *page)
 148 {
 149         if (PageSwapCache(page))
 150                 return page->offset;
 151         return 0;
 152 }
 153
 154 /*
 155  * Work out if there are any other processes sharing this page, ignoring
 156  * any page reference coming from the swap cache, or from outstanding
 157  * swap IO on this page.  (The page cache _does_ count as another valid
 158  * reference to the page, however.)
 159  */
 160 static inline int is_page_shared(struct page *page)
 161 {
 162         unsigned int count;
 163         if (PageReserved(page))
 164                 return 1;
 165         count = atomic_read(&page->count);
 166         if (PageSwapCache(page))
 167                 count += swap_count(page->offset) - 2;
 168         if (PageFreeAfter(page))
 169                 count--;
 170         return  count > 1;
 171 }
 172
 173 #endif /* __KERNEL__*/
 174
 175 #endif /* _LINUX_SWAP_H */