4 #include <linux/spinlock.h>
5 #include <linux/linkage.h>
6 #include <linux/mmzone.h>
7 #include <linux/list.h>
8 #include <linux/memcontrol.h>
9 #include <linux/sched.h>
11 #include <asm/atomic.h>
14 struct notifier_block
;
18 #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
19 #define SWAP_FLAG_PRIO_MASK 0x7fff
20 #define SWAP_FLAG_PRIO_SHIFT 0
22 static inline int current_is_kswapd(void)
24 return current
->flags
& PF_KSWAPD
;
28 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
29 * be swapped to. The swap type and the offset into that swap type are
30 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits
31 * for the type means that the maximum number of swapcache pages is 27 bits
32 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
33 * the type/offset into the pte as 5/27 as well.
35 #define MAX_SWAPFILES_SHIFT 5
36 #ifndef CONFIG_MIGRATION
37 #define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
39 /* Use last two entries for page migration swap entries */
40 #define MAX_SWAPFILES ((1 << MAX_SWAPFILES_SHIFT)-2)
41 #define SWP_MIGRATION_READ MAX_SWAPFILES
42 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + 1)
46 * Magic header for a swap area. The first part of the union is
47 * what the swap magic looks like for the old (limited to 128MB)
48 * swap area format, the second part of the union adds - in the
49 * old reserved area - some extra information. Note that the first
50 * kilobyte is reserved for boot loader or disk label stuff...
52 * Having the magic at the end of the PAGE_SIZE makes detecting swap
53 * areas somewhat tricky on machines that support multiple page sizes.
54 * For 2.5 we'll probably want to move the magic to just beyond the
59 char reserved
[PAGE_SIZE
- 10];
60 char magic
[10]; /* SWAP-SPACE or SWAPSPACE2 */
63 char bootbits
[1024]; /* Space for disklabel etc. */
67 unsigned char sws_uuid
[16];
68 unsigned char sws_volume
[16];
74 /* A swap entry has to fit into a "unsigned long", as
75 * the entry is hidden in the "index" field of the
76 * swapper address space.
83 * current->reclaim_state points to one of these when a task is running
86 struct reclaim_state
{
87 unsigned long reclaimed_slab
;
94 struct writeback_control
;
98 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
99 * disk blocks. A list of swap extents maps the entire swapfile. (Where the
100 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
101 * from setup, they're handled identically.
103 * We always assume that blocks are of size PAGE_SIZE.
106 struct list_head list
;
109 sector_t start_block
;
113 * Max bad pages in the new format..
115 #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
116 #define MAX_SWAP_BADPAGES \
117 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
120 SWP_USED
= (1 << 0), /* is slot in swap_info[] used? */
121 SWP_WRITEOK
= (1 << 1), /* ok to write to this swap? */
122 SWP_ACTIVE
= (SWP_USED
| SWP_WRITEOK
),
123 /* add others here before... */
124 SWP_SCANNING
= (1 << 8), /* refcount in scan_swap_map */
127 #define SWAP_CLUSTER_MAX 32
129 #define SWAP_MAP_MAX 0x7fff
130 #define SWAP_MAP_BAD 0x8000
133 * The in-memory structure used to track swap areas.
135 struct swap_info_struct
{
137 int prio
; /* swap priority */
138 struct file
*swap_file
;
139 struct block_device
*bdev
;
140 struct list_head extent_list
;
141 struct swap_extent
*curr_swap_extent
;
142 unsigned old_block_size
;
143 unsigned short * swap_map
;
144 unsigned int lowest_bit
;
145 unsigned int highest_bit
;
146 unsigned int cluster_next
;
147 unsigned int cluster_nr
;
150 unsigned int inuse_pages
;
151 int next
; /* next entry on swap list */
155 int head
; /* head of priority-ordered swapfile list */
156 int next
; /* swapfile to be used next */
159 /* Swap 50% full? Release swapcache more aggressively.. */
160 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
162 /* linux/mm/page_alloc.c */
163 extern unsigned long totalram_pages
;
164 extern unsigned long totalreserve_pages
;
165 extern long nr_swap_pages
;
166 extern unsigned int nr_free_buffer_pages(void);
167 extern unsigned int nr_free_pagecache_pages(void);
169 /* Definition of global_page_state not available yet */
170 #define nr_free_pages() global_page_state(NR_FREE_PAGES)
173 /* linux/mm/swap.c */
174 extern void __lru_cache_add(struct page
*, enum lru_list lru
);
175 extern void lru_cache_add_lru(struct page
*, enum lru_list lru
);
176 extern void activate_page(struct page
*);
177 extern void mark_page_accessed(struct page
*);
178 extern void lru_add_drain(void);
179 extern int lru_add_drain_all(void);
180 extern void rotate_reclaimable_page(struct page
*page
);
181 extern void swap_setup(void);
184 * lru_cache_add: add a page to the page lists
185 * @page: the page to add
187 static inline void lru_cache_add(struct page
*page
)
189 __lru_cache_add(page
, LRU_INACTIVE
);
192 static inline void lru_cache_add_active(struct page
*page
)
194 __lru_cache_add(page
, LRU_ACTIVE
);
197 /* linux/mm/vmscan.c */
198 extern unsigned long try_to_free_pages(struct zonelist
*zonelist
, int order
,
200 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup
*mem
,
202 extern int __isolate_lru_page(struct page
*page
, int mode
);
203 extern unsigned long shrink_all_memory(unsigned long nr_pages
);
204 extern int vm_swappiness
;
205 extern int remove_mapping(struct address_space
*mapping
, struct page
*page
);
206 extern long vm_total_pages
;
209 extern int zone_reclaim_mode
;
210 extern int sysctl_min_unmapped_ratio
;
211 extern int sysctl_min_slab_ratio
;
212 extern int zone_reclaim(struct zone
*, gfp_t
, unsigned int);
214 #define zone_reclaim_mode 0
215 static inline int zone_reclaim(struct zone
*z
, gfp_t mask
, unsigned int order
)
221 extern int kswapd_run(int nid
);
224 /* linux/mm/shmem.c */
225 extern int shmem_unuse(swp_entry_t entry
, struct page
*page
);
226 #endif /* CONFIG_MMU */
228 extern void swap_unplug_io_fn(struct backing_dev_info
*, struct page
*);
231 /* linux/mm/page_io.c */
232 extern int swap_readpage(struct file
*, struct page
*);
233 extern int swap_writepage(struct page
*page
, struct writeback_control
*wbc
);
234 extern void end_swap_bio_read(struct bio
*bio
, int err
);
236 /* linux/mm/swap_state.c */
237 extern struct address_space swapper_space
;
238 #define total_swapcache_pages swapper_space.nrpages
239 extern void show_swap_cache_info(void);
240 extern int add_to_swap(struct page
*, gfp_t
);
241 extern int add_to_swap_cache(struct page
*, swp_entry_t
, gfp_t
);
242 extern void __delete_from_swap_cache(struct page
*);
243 extern void delete_from_swap_cache(struct page
*);
244 extern void free_page_and_swap_cache(struct page
*);
245 extern void free_pages_and_swap_cache(struct page
**, int);
246 extern struct page
*lookup_swap_cache(swp_entry_t
);
247 extern struct page
*read_swap_cache_async(swp_entry_t
, gfp_t
,
248 struct vm_area_struct
*vma
, unsigned long addr
);
249 extern struct page
*swapin_readahead(swp_entry_t
, gfp_t
,
250 struct vm_area_struct
*vma
, unsigned long addr
);
252 /* linux/mm/swapfile.c */
253 extern long total_swap_pages
;
254 extern void si_swapinfo(struct sysinfo
*);
255 extern swp_entry_t
get_swap_page(void);
256 extern swp_entry_t
get_swap_page_of_type(int);
257 extern int swap_duplicate(swp_entry_t
);
258 extern int valid_swaphandles(swp_entry_t
, unsigned long *);
259 extern void swap_free(swp_entry_t
);
260 extern void free_swap_and_cache(swp_entry_t
);
261 extern int swap_type_of(dev_t
, sector_t
, struct block_device
**);
262 extern unsigned int count_swap_pages(int, int);
263 extern sector_t
map_swap_page(struct swap_info_struct
*, pgoff_t
);
264 extern sector_t
swapdev_block(int, pgoff_t
);
265 extern struct swap_info_struct
*get_swap_info_struct(unsigned);
266 extern int can_share_swap_page(struct page
*);
267 extern int remove_exclusive_swap_page(struct page
*);
268 extern int remove_exclusive_swap_page_ref(struct page
*);
269 struct backing_dev_info
;
271 /* linux/mm/thrash.c */
272 extern struct mm_struct
* swap_token_mm
;
273 extern void grab_swap_token(void);
274 extern void __put_swap_token(struct mm_struct
*);
276 static inline int has_swap_token(struct mm_struct
*mm
)
278 return (mm
== swap_token_mm
);
281 static inline void put_swap_token(struct mm_struct
*mm
)
283 if (has_swap_token(mm
))
284 __put_swap_token(mm
);
287 static inline void disable_swap_token(void)
289 put_swap_token(swap_token_mm
);
292 #else /* CONFIG_SWAP */
294 #define total_swap_pages 0
295 #define total_swapcache_pages 0UL
297 #define si_swapinfo(val) \
298 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
299 /* only sparc can not include linux/pagemap.h in this file
300 * so leave page_cache_release and release_pages undeclared... */
301 #define free_page_and_swap_cache(page) \
302 page_cache_release(page)
303 #define free_pages_and_swap_cache(pages, nr) \
304 release_pages((pages), (nr), 0);
306 static inline void show_swap_cache_info(void)
310 static inline void free_swap_and_cache(swp_entry_t swp
)
314 static inline int swap_duplicate(swp_entry_t swp
)
319 static inline void swap_free(swp_entry_t swp
)
323 static inline struct page
*swapin_readahead(swp_entry_t swp
, gfp_t gfp_mask
,
324 struct vm_area_struct
*vma
, unsigned long addr
)
329 static inline struct page
*lookup_swap_cache(swp_entry_t swp
)
334 #define can_share_swap_page(p) (page_mapcount(p) == 1)
336 static inline int add_to_swap_cache(struct page
*page
, swp_entry_t entry
,
342 static inline void __delete_from_swap_cache(struct page
*page
)
346 static inline void delete_from_swap_cache(struct page
*page
)
350 #define swap_token_default_timeout 0
352 static inline int remove_exclusive_swap_page(struct page
*p
)
357 static inline int remove_exclusive_swap_page_ref(struct page
*page
)
362 static inline swp_entry_t
get_swap_page(void)
369 /* linux/mm/thrash.c */
370 #define put_swap_token(x) do { } while(0)
371 #define grab_swap_token() do { } while(0)
372 #define has_swap_token(x) 0
373 #define disable_swap_token() do { } while(0)
375 #endif /* CONFIG_SWAP */
376 #endif /* __KERNEL__*/
377 #endif /* _LINUX_SWAP_H */