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 #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
14 #define SWAP_FLAG_PRIO_MASK 0x7fff
15 #define SWAP_FLAG_PRIO_SHIFT 0
17 static inline int current_is_kswapd(void)
19 return current
->flags
& PF_KSWAPD
;
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.
30 #define MAX_SWAPFILES_SHIFT 5
31 #ifndef CONFIG_MIGRATION
32 #define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
34 /* Use last two entries for page migration swap entries */
35 #define MAX_SWAPFILES ((1 << MAX_SWAPFILES_SHIFT)-2)
36 #define SWP_MIGRATION_READ MAX_SWAPFILES
37 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + 1)
41 * Magic header for a swap area. The first part of the union is
42 * what the swap magic looks like for the old (limited to 128MB)
43 * swap area format, the second part of the union adds - in the
44 * old reserved area - some extra information. Note that the first
45 * kilobyte is reserved for boot loader or disk label stuff...
47 * Having the magic at the end of the PAGE_SIZE makes detecting swap
48 * areas somewhat tricky on machines that support multiple page sizes.
49 * For 2.5 we'll probably want to move the magic to just beyond the
54 char reserved
[PAGE_SIZE
- 10];
55 char magic
[10]; /* SWAP-SPACE or SWAPSPACE2 */
58 char bootbits
[1024]; /* Space for disklabel etc. */
62 unsigned char sws_uuid
[16];
63 unsigned char sws_volume
[16];
69 /* A swap entry has to fit into a "unsigned long", as
70 * the entry is hidden in the "index" field of the
71 * swapper address space.
78 * current->reclaim_state points to one of these when a task is running
81 struct reclaim_state
{
82 unsigned long reclaimed_slab
;
89 struct writeback_control
;
93 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
94 * disk blocks. A list of swap extents maps the entire swapfile. (Where the
95 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
96 * from setup, they're handled identically.
98 * We always assume that blocks are of size PAGE_SIZE.
101 struct list_head list
;
104 sector_t start_block
;
108 * Max bad pages in the new format..
110 #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
111 #define MAX_SWAP_BADPAGES \
112 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
115 SWP_USED
= (1 << 0), /* is slot in swap_info[] used? */
116 SWP_WRITEOK
= (1 << 1), /* ok to write to this swap? */
117 SWP_ACTIVE
= (SWP_USED
| SWP_WRITEOK
),
118 /* add others here before... */
119 SWP_SCANNING
= (1 << 8), /* refcount in scan_swap_map */
122 #define SWAP_CLUSTER_MAX 32
124 #define SWAP_MAP_MAX 0x7fff
125 #define SWAP_MAP_BAD 0x8000
128 * The in-memory structure used to track swap areas.
130 struct swap_info_struct
{
132 int prio
; /* swap priority */
133 struct file
*swap_file
;
134 struct block_device
*bdev
;
135 struct list_head extent_list
;
136 struct swap_extent
*curr_swap_extent
;
137 unsigned old_block_size
;
138 unsigned short * swap_map
;
139 unsigned int lowest_bit
;
140 unsigned int highest_bit
;
141 unsigned int cluster_next
;
142 unsigned int cluster_nr
;
145 unsigned int inuse_pages
;
146 int next
; /* next entry on swap list */
150 int head
; /* head of priority-ordered swapfile list */
151 int next
; /* swapfile to be used next */
154 /* Swap 50% full? Release swapcache more aggressively.. */
155 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
157 /* linux/mm/oom_kill.c */
158 extern void out_of_memory(struct zonelist
*zonelist
, gfp_t gfp_mask
, int order
);
160 /* linux/mm/memory.c */
161 extern void swapin_readahead(swp_entry_t
, unsigned long, struct vm_area_struct
*);
163 /* linux/mm/page_alloc.c */
164 extern unsigned long totalram_pages
;
165 extern unsigned long totalreserve_pages
;
166 extern long nr_swap_pages
;
167 extern unsigned int nr_free_pages(void);
168 extern unsigned int nr_free_pages_pgdat(pg_data_t
*pgdat
);
169 extern unsigned int nr_free_buffer_pages(void);
170 extern unsigned int nr_free_pagecache_pages(void);
172 /* linux/mm/swap.c */
173 extern void FASTCALL(lru_cache_add(struct page
*));
174 extern void FASTCALL(lru_cache_add_active(struct page
*));
175 extern void FASTCALL(activate_page(struct page
*));
176 extern void FASTCALL(mark_page_accessed(struct page
*));
177 extern void lru_add_drain(void);
178 extern int lru_add_drain_all(void);
179 extern int rotate_reclaimable_page(struct page
*page
);
180 extern void swap_setup(void);
182 /* linux/mm/vmscan.c */
183 extern unsigned long try_to_free_pages(struct zone
**, gfp_t
);
184 extern unsigned long shrink_all_memory(unsigned long nr_pages
);
185 extern int vm_swappiness
;
186 extern int remove_mapping(struct address_space
*mapping
, struct page
*page
);
187 extern long vm_total_pages
;
190 extern int zone_reclaim_mode
;
191 extern int sysctl_min_unmapped_ratio
;
192 extern int zone_reclaim(struct zone
*, gfp_t
, unsigned int);
194 #define zone_reclaim_mode 0
195 static inline int zone_reclaim(struct zone
*z
, gfp_t mask
, unsigned int order
)
201 extern int kswapd_run(int nid
);
204 /* linux/mm/shmem.c */
205 extern int shmem_unuse(swp_entry_t entry
, struct page
*page
);
206 #endif /* CONFIG_MMU */
208 extern void swap_unplug_io_fn(struct backing_dev_info
*, struct page
*);
211 /* linux/mm/page_io.c */
212 extern int swap_readpage(struct file
*, struct page
*);
213 extern int swap_writepage(struct page
*page
, struct writeback_control
*wbc
);
214 extern int rw_swap_page_sync(int, swp_entry_t
, struct page
*);
216 /* linux/mm/swap_state.c */
217 extern struct address_space swapper_space
;
218 #define total_swapcache_pages swapper_space.nrpages
219 extern void show_swap_cache_info(void);
220 extern int add_to_swap(struct page
*, gfp_t
);
221 extern void __delete_from_swap_cache(struct page
*);
222 extern void delete_from_swap_cache(struct page
*);
223 extern int move_to_swap_cache(struct page
*, swp_entry_t
);
224 extern int move_from_swap_cache(struct page
*, unsigned long,
225 struct address_space
*);
226 extern void free_page_and_swap_cache(struct page
*);
227 extern void free_pages_and_swap_cache(struct page
**, int);
228 extern struct page
* lookup_swap_cache(swp_entry_t
);
229 extern struct page
* read_swap_cache_async(swp_entry_t
, struct vm_area_struct
*vma
,
231 /* linux/mm/swapfile.c */
232 extern long total_swap_pages
;
233 extern unsigned int nr_swapfiles
;
234 extern void si_swapinfo(struct sysinfo
*);
235 extern swp_entry_t
get_swap_page(void);
236 extern swp_entry_t
get_swap_page_of_type(int);
237 extern int swap_duplicate(swp_entry_t
);
238 extern int valid_swaphandles(swp_entry_t
, unsigned long *);
239 extern void swap_free(swp_entry_t
);
240 extern void free_swap_and_cache(swp_entry_t
);
241 extern int swap_type_of(dev_t
);
242 extern unsigned int count_swap_pages(int, int);
243 extern sector_t
map_swap_page(struct swap_info_struct
*, pgoff_t
);
244 extern struct swap_info_struct
*get_swap_info_struct(unsigned);
245 extern int can_share_swap_page(struct page
*);
246 extern int remove_exclusive_swap_page(struct page
*);
247 struct backing_dev_info
;
249 extern spinlock_t swap_lock
;
251 /* linux/mm/thrash.c */
252 extern struct mm_struct
* swap_token_mm
;
253 extern unsigned long swap_token_default_timeout
;
254 extern void grab_swap_token(void);
255 extern void __put_swap_token(struct mm_struct
*);
257 static inline int has_swap_token(struct mm_struct
*mm
)
259 return (mm
== swap_token_mm
);
262 static inline void put_swap_token(struct mm_struct
*mm
)
264 if (has_swap_token(mm
))
265 __put_swap_token(mm
);
268 static inline void disable_swap_token(void)
270 put_swap_token(swap_token_mm
);
273 #else /* CONFIG_SWAP */
275 #define total_swap_pages 0
276 #define total_swapcache_pages 0UL
278 #define si_swapinfo(val) \
279 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
280 /* only sparc can not include linux/pagemap.h in this file
281 * so leave page_cache_release and release_pages undeclared... */
282 #define free_page_and_swap_cache(page) \
283 page_cache_release(page)
284 #define free_pages_and_swap_cache(pages, nr) \
285 release_pages((pages), (nr), 0);
287 static inline void show_swap_cache_info(void)
291 static inline void free_swap_and_cache(swp_entry_t swp
)
295 static inline int swap_duplicate(swp_entry_t swp
)
300 static inline void swap_free(swp_entry_t swp
)
304 static inline struct page
*read_swap_cache_async(swp_entry_t swp
,
305 struct vm_area_struct
*vma
, unsigned long addr
)
310 static inline struct page
*lookup_swap_cache(swp_entry_t swp
)
315 static inline int valid_swaphandles(swp_entry_t entry
, unsigned long *offset
)
320 #define can_share_swap_page(p) (page_mapcount(p) == 1)
322 static inline int move_to_swap_cache(struct page
*page
, swp_entry_t entry
)
327 static inline int move_from_swap_cache(struct page
*page
, unsigned long index
,
328 struct address_space
*mapping
)
333 static inline void __delete_from_swap_cache(struct page
*page
)
337 static inline void delete_from_swap_cache(struct page
*page
)
341 #define swap_token_default_timeout 0
343 static inline int remove_exclusive_swap_page(struct page
*p
)
348 static inline swp_entry_t
get_swap_page(void)
355 /* linux/mm/thrash.c */
356 #define put_swap_token(x) do { } while(0)
357 #define grab_swap_token() do { } while(0)
358 #define has_swap_token(x) 0
359 #define disable_swap_token() do { } while(0)
361 #endif /* CONFIG_SWAP */
362 #endif /* __KERNEL__*/
363 #endif /* _LINUX_SWAP_H */