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>
10 #include <asm/atomic.h>
13 struct notifier_block;
15 #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
16 #define SWAP_FLAG_PRIO_MASK 0x7fff
17 #define SWAP_FLAG_PRIO_SHIFT 0
19 static inline int current_is_kswapd(void)
21 return current->flags & PF_KSWAPD;
25 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
26 * be swapped to. The swap type and the offset into that swap type are
27 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits
28 * for the type means that the maximum number of swapcache pages is 27 bits
29 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
30 * the type/offset into the pte as 5/27 as well.
32 #define MAX_SWAPFILES_SHIFT 5
33 #ifndef CONFIG_MIGRATION
34 #define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
36 /* Use last two entries for page migration swap entries */
37 #define MAX_SWAPFILES ((1 << MAX_SWAPFILES_SHIFT)-2)
38 #define SWP_MIGRATION_READ MAX_SWAPFILES
39 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + 1)
43 * Magic header for a swap area. The first part of the union is
44 * what the swap magic looks like for the old (limited to 128MB)
45 * swap area format, the second part of the union adds - in the
46 * old reserved area - some extra information. Note that the first
47 * kilobyte is reserved for boot loader or disk label stuff...
49 * Having the magic at the end of the PAGE_SIZE makes detecting swap
50 * areas somewhat tricky on machines that support multiple page sizes.
51 * For 2.5 we'll probably want to move the magic to just beyond the
56 char reserved[PAGE_SIZE - 10];
57 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
60 char bootbits[1024]; /* Space for disklabel etc. */
64 unsigned char sws_uuid[16];
65 unsigned char sws_volume[16];
71 /* A swap entry has to fit into a "unsigned long", as
72 * the entry is hidden in the "index" field of the
73 * swapper address space.
80 * current->reclaim_state points to one of these when a task is running
83 struct reclaim_state {
84 unsigned long reclaimed_slab;
91 struct writeback_control;
95 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
96 * disk blocks. A list of swap extents maps the entire swapfile. (Where the
97 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
98 * from setup, they're handled identically.
100 * We always assume that blocks are of size PAGE_SIZE.
103 struct list_head list;
106 sector_t start_block;
110 * Max bad pages in the new format..
112 #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
113 #define MAX_SWAP_BADPAGES \
114 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
117 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
118 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
119 SWP_ACTIVE = (SWP_USED | SWP_WRITEOK),
120 /* add others here before... */
121 SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
124 #define SWAP_CLUSTER_MAX 32
126 #define SWAP_MAP_MAX 0x7fff
127 #define SWAP_MAP_BAD 0x8000
130 * The in-memory structure used to track swap areas.
132 struct swap_info_struct {
134 int prio; /* swap priority */
135 struct file *swap_file;
136 struct block_device *bdev;
137 struct list_head extent_list;
138 struct swap_extent *curr_swap_extent;
139 unsigned old_block_size;
140 unsigned short * swap_map;
141 unsigned int lowest_bit;
142 unsigned int highest_bit;
143 unsigned int cluster_next;
144 unsigned int cluster_nr;
147 unsigned int inuse_pages;
148 int next; /* next entry on swap list */
152 int head; /* head of priority-ordered swapfile list */
153 int next; /* swapfile to be used next */
156 /* Swap 50% full? Release swapcache more aggressively.. */
157 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
159 /* linux/mm/oom_kill.c */
160 extern void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order);
161 extern int register_oom_notifier(struct notifier_block *nb);
162 extern int unregister_oom_notifier(struct notifier_block *nb);
164 /* linux/mm/memory.c */
165 extern void swapin_readahead(swp_entry_t, unsigned long, struct vm_area_struct *);
167 /* linux/mm/page_alloc.c */
168 extern unsigned long totalram_pages;
169 extern unsigned long totalreserve_pages;
170 extern long nr_swap_pages;
171 extern unsigned int nr_free_pages(void);
172 extern unsigned int nr_free_pages_pgdat(pg_data_t *pgdat);
173 extern unsigned int nr_free_buffer_pages(void);
174 extern unsigned int nr_free_pagecache_pages(void);
176 /* linux/mm/swap.c */
177 extern void FASTCALL(lru_cache_add(struct page *));
178 extern void FASTCALL(lru_cache_add_active(struct page *));
179 extern void FASTCALL(activate_page(struct page *));
180 extern void FASTCALL(mark_page_accessed(struct page *));
181 extern void lru_add_drain(void);
182 extern int lru_add_drain_all(void);
183 extern int rotate_reclaimable_page(struct page *page);
184 extern void swap_setup(void);
186 /* linux/mm/vmscan.c */
187 extern unsigned long try_to_free_pages(struct zone **, gfp_t);
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;
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);
199 #define zone_reclaim_mode 0
200 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
206 extern int kswapd_run(int nid);
209 /* linux/mm/shmem.c */
210 extern int shmem_unuse(swp_entry_t entry, struct page *page);
211 #endif /* CONFIG_MMU */
213 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);
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 int rw_swap_page_sync(int, swp_entry_t, struct page *);
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,
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);
247 extern unsigned int count_swap_pages(int, int);
248 extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
249 extern struct swap_info_struct *get_swap_info_struct(unsigned);
250 extern int can_share_swap_page(struct page *);
251 extern int remove_exclusive_swap_page(struct page *);
252 struct backing_dev_info;
254 extern spinlock_t swap_lock;
256 /* linux/mm/thrash.c */
257 extern struct mm_struct * swap_token_mm;
258 extern unsigned long swap_token_default_timeout;
259 extern void grab_swap_token(void);
260 extern void __put_swap_token(struct mm_struct *);
262 static inline int has_swap_token(struct mm_struct *mm)
264 return (mm == swap_token_mm);
267 static inline void put_swap_token(struct mm_struct *mm)
269 if (has_swap_token(mm))
270 __put_swap_token(mm);
273 static inline void disable_swap_token(void)
275 put_swap_token(swap_token_mm);
278 #else /* CONFIG_SWAP */
280 #define total_swap_pages 0
281 #define total_swapcache_pages 0UL
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);
292 static inline void show_swap_cache_info(void)
296 static inline void free_swap_and_cache(swp_entry_t swp)
300 static inline int swap_duplicate(swp_entry_t swp)
305 static inline void swap_free(swp_entry_t swp)
309 static inline struct page *read_swap_cache_async(swp_entry_t swp,
310 struct vm_area_struct *vma, unsigned long addr)
315 static inline struct page *lookup_swap_cache(swp_entry_t swp)
320 static inline int valid_swaphandles(swp_entry_t entry, unsigned long *offset)
325 #define can_share_swap_page(p) (page_mapcount(p) == 1)
327 static inline int move_to_swap_cache(struct page *page, swp_entry_t entry)
332 static inline int move_from_swap_cache(struct page *page, unsigned long index,
333 struct address_space *mapping)
338 static inline void __delete_from_swap_cache(struct page *page)
342 static inline void delete_from_swap_cache(struct page *page)
346 #define swap_token_default_timeout 0
348 static inline int remove_exclusive_swap_page(struct page *p)
353 static inline swp_entry_t get_swap_page(void)
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)
366 #endif /* CONFIG_SWAP */
367 #endif /* __KERNEL__*/
368 #endif /* _LINUX_SWAP_H */