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
;
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
21 static inline int current_is_kswapd(void)
23 return current
->flags
& PF_KSWAPD
;
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.
34 #define MAX_SWAPFILES_SHIFT 5
35 #ifndef CONFIG_MIGRATION
36 #define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
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)
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...
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
58 char reserved
[PAGE_SIZE
- 10];
59 char magic
[10]; /* SWAP-SPACE or SWAPSPACE2 */
62 char bootbits
[1024]; /* Space for disklabel etc. */
66 unsigned char sws_uuid
[16];
67 unsigned char sws_volume
[16];
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.
82 * current->reclaim_state points to one of these when a task is running
85 struct reclaim_state
{
86 unsigned long reclaimed_slab
;
93 struct writeback_control
;
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.
102 * We always assume that blocks are of size PAGE_SIZE.
105 struct list_head list
;
108 sector_t start_block
;
112 * Max bad pages in the new format..
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))
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 */
126 #define SWAP_CLUSTER_MAX 32
128 #define SWAP_MAP_MAX 0x7fff
129 #define SWAP_MAP_BAD 0x8000
132 * The in-memory structure used to track swap areas.
134 struct swap_info_struct
{
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
;
149 unsigned int inuse_pages
;
150 int next
; /* next entry on swap list */
154 int head
; /* head of priority-ordered swapfile list */
155 int next
; /* swapfile to be used next */
158 /* Swap 50% full? Release swapcache more aggressively.. */
159 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
161 /* linux/mm/oom_kill.c */
162 extern void out_of_memory(struct zonelist
*zonelist
, gfp_t gfp_mask
, int order
);
163 extern int register_oom_notifier(struct notifier_block
*nb
);
164 extern int unregister_oom_notifier(struct notifier_block
*nb
);
166 /* linux/mm/memory.c */
167 extern void swapin_readahead(swp_entry_t
, unsigned long, struct vm_area_struct
*);
169 /* linux/mm/page_alloc.c */
170 extern unsigned long totalram_pages
;
171 extern unsigned long totalreserve_pages
;
172 extern long nr_swap_pages
;
173 extern unsigned int nr_free_pages(void);
174 extern unsigned int nr_free_pages_pgdat(pg_data_t
*pgdat
);
175 extern unsigned int nr_free_buffer_pages(void);
176 extern unsigned int nr_free_pagecache_pages(void);
178 /* linux/mm/swap.c */
179 extern void FASTCALL(lru_cache_add(struct page
*));
180 extern void FASTCALL(lru_cache_add_active(struct page
*));
181 extern void FASTCALL(activate_page(struct page
*));
182 extern void FASTCALL(mark_page_accessed(struct page
*));
183 extern void lru_add_drain(void);
184 extern int lru_add_drain_all(void);
185 extern int rotate_reclaimable_page(struct page
*page
);
186 extern void swap_setup(void);
188 /* linux/mm/vmscan.c */
189 extern unsigned long try_to_free_pages(struct zone
**, gfp_t
);
190 extern unsigned long shrink_all_memory(unsigned long nr_pages
);
191 extern int vm_swappiness
;
192 extern int remove_mapping(struct address_space
*mapping
, struct page
*page
);
193 extern long vm_total_pages
;
196 extern int zone_reclaim_mode
;
197 extern int sysctl_min_unmapped_ratio
;
198 extern int sysctl_min_slab_ratio
;
199 extern int zone_reclaim(struct zone
*, gfp_t
, unsigned int);
201 #define zone_reclaim_mode 0
202 static inline int zone_reclaim(struct zone
*z
, gfp_t mask
, unsigned int order
)
208 extern int kswapd_run(int nid
);
211 /* linux/mm/shmem.c */
212 extern int shmem_unuse(swp_entry_t entry
, struct page
*page
);
213 #endif /* CONFIG_MMU */
215 extern void swap_unplug_io_fn(struct backing_dev_info
*, struct page
*);
218 /* linux/mm/page_io.c */
219 extern int swap_readpage(struct file
*, struct page
*);
220 extern int swap_writepage(struct page
*page
, struct writeback_control
*wbc
);
221 extern int end_swap_bio_read(struct bio
*bio
, unsigned int bytes_done
, int err
);
223 /* linux/mm/swap_state.c */
224 extern struct address_space swapper_space
;
225 #define total_swapcache_pages swapper_space.nrpages
226 extern void show_swap_cache_info(void);
227 extern int add_to_swap(struct page
*, gfp_t
);
228 extern void __delete_from_swap_cache(struct page
*);
229 extern void delete_from_swap_cache(struct page
*);
230 extern int move_to_swap_cache(struct page
*, swp_entry_t
);
231 extern int move_from_swap_cache(struct page
*, unsigned long,
232 struct address_space
*);
233 extern void free_page_and_swap_cache(struct page
*);
234 extern void free_pages_and_swap_cache(struct page
**, int);
235 extern struct page
* lookup_swap_cache(swp_entry_t
);
236 extern struct page
* read_swap_cache_async(swp_entry_t
, struct vm_area_struct
*vma
,
238 /* linux/mm/swapfile.c */
239 extern long total_swap_pages
;
240 extern unsigned int nr_swapfiles
;
241 extern void si_swapinfo(struct sysinfo
*);
242 extern swp_entry_t
get_swap_page(void);
243 extern swp_entry_t
get_swap_page_of_type(int);
244 extern int swap_duplicate(swp_entry_t
);
245 extern int valid_swaphandles(swp_entry_t
, unsigned long *);
246 extern void swap_free(swp_entry_t
);
247 extern void free_swap_and_cache(swp_entry_t
);
248 extern int swap_type_of(dev_t
, sector_t
);
249 extern unsigned int count_swap_pages(int, int);
250 extern sector_t
map_swap_page(struct swap_info_struct
*, pgoff_t
);
251 extern sector_t
swapdev_block(int, pgoff_t
);
252 extern struct swap_info_struct
*get_swap_info_struct(unsigned);
253 extern int can_share_swap_page(struct page
*);
254 extern int remove_exclusive_swap_page(struct page
*);
255 struct backing_dev_info
;
257 extern spinlock_t swap_lock
;
259 /* linux/mm/thrash.c */
260 extern struct mm_struct
* swap_token_mm
;
261 extern void grab_swap_token(void);
262 extern void __put_swap_token(struct mm_struct
*);
264 static inline int has_swap_token(struct mm_struct
*mm
)
266 return (mm
== swap_token_mm
);
269 static inline void put_swap_token(struct mm_struct
*mm
)
271 if (has_swap_token(mm
))
272 __put_swap_token(mm
);
275 static inline void disable_swap_token(void)
277 put_swap_token(swap_token_mm
);
280 #else /* CONFIG_SWAP */
282 #define total_swap_pages 0
283 #define total_swapcache_pages 0UL
285 #define si_swapinfo(val) \
286 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
287 /* only sparc can not include linux/pagemap.h in this file
288 * so leave page_cache_release and release_pages undeclared... */
289 #define free_page_and_swap_cache(page) \
290 page_cache_release(page)
291 #define free_pages_and_swap_cache(pages, nr) \
292 release_pages((pages), (nr), 0);
294 static inline void show_swap_cache_info(void)
298 static inline void free_swap_and_cache(swp_entry_t swp
)
302 static inline int swap_duplicate(swp_entry_t swp
)
307 static inline void swap_free(swp_entry_t swp
)
311 static inline struct page
*read_swap_cache_async(swp_entry_t swp
,
312 struct vm_area_struct
*vma
, unsigned long addr
)
317 static inline struct page
*lookup_swap_cache(swp_entry_t swp
)
322 static inline int valid_swaphandles(swp_entry_t entry
, unsigned long *offset
)
327 #define can_share_swap_page(p) (page_mapcount(p) == 1)
329 static inline int move_to_swap_cache(struct page
*page
, swp_entry_t entry
)
334 static inline int move_from_swap_cache(struct page
*page
, unsigned long index
,
335 struct address_space
*mapping
)
340 static inline void __delete_from_swap_cache(struct page
*page
)
344 static inline void delete_from_swap_cache(struct page
*page
)
348 #define swap_token_default_timeout 0
350 static inline int remove_exclusive_swap_page(struct page
*p
)
355 static inline swp_entry_t
get_swap_page(void)
362 /* linux/mm/thrash.c */
363 #define put_swap_token(x) do { } while(0)
364 #define grab_swap_token() do { } while(0)
365 #define has_swap_token(x) 0
366 #define disable_swap_token() do { } while(0)
368 #endif /* CONFIG_SWAP */
369 #endif /* __KERNEL__*/
370 #endif /* _LINUX_SWAP_H */