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/page_alloc.c */
162 extern unsigned long totalram_pages;
163 extern unsigned long totalreserve_pages;
164 extern long nr_swap_pages;
165 extern unsigned int nr_free_buffer_pages(void);
166 extern unsigned int nr_free_pagecache_pages(void);
168 /* Definition of global_page_state not available yet */
169 #define nr_free_pages() global_page_state(NR_FREE_PAGES)
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 **zones, int order,
185 extern unsigned long shrink_all_memory(unsigned long nr_pages);
186 extern int vm_swappiness;
187 extern int remove_mapping(struct address_space *mapping, struct page *page);
188 extern long vm_total_pages;
191 extern int zone_reclaim_mode;
192 extern int sysctl_min_unmapped_ratio;
193 extern int sysctl_min_slab_ratio;
194 extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
196 #define zone_reclaim_mode 0
197 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
203 extern int kswapd_run(int nid);
206 /* linux/mm/shmem.c */
207 extern int shmem_unuse(swp_entry_t entry, struct page *page);
208 #endif /* CONFIG_MMU */
210 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);
213 /* linux/mm/page_io.c */
214 extern int swap_readpage(struct file *, struct page *);
215 extern int swap_writepage(struct page *page, struct writeback_control *wbc);
216 extern void end_swap_bio_read(struct bio *bio, int err);
218 /* linux/mm/swap_state.c */
219 extern struct address_space swapper_space;
220 #define total_swapcache_pages swapper_space.nrpages
221 extern void show_swap_cache_info(void);
222 extern int add_to_swap(struct page *, gfp_t);
223 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
224 extern void __delete_from_swap_cache(struct page *);
225 extern void delete_from_swap_cache(struct page *);
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, gfp_t,
230 struct vm_area_struct *vma, unsigned long addr);
231 extern struct page *swapin_readahead(swp_entry_t, gfp_t,
232 struct vm_area_struct *vma, unsigned long addr);
234 /* linux/mm/swapfile.c */
235 extern long total_swap_pages;
236 extern unsigned int nr_swapfiles;
237 extern void si_swapinfo(struct sysinfo *);
238 extern swp_entry_t get_swap_page(void);
239 extern swp_entry_t get_swap_page_of_type(int);
240 extern int swap_duplicate(swp_entry_t);
241 extern int valid_swaphandles(swp_entry_t, unsigned long *);
242 extern void swap_free(swp_entry_t);
243 extern void free_swap_and_cache(swp_entry_t);
244 extern int swap_type_of(dev_t, sector_t, struct block_device **);
245 extern unsigned int count_swap_pages(int, int);
246 extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
247 extern sector_t swapdev_block(int, pgoff_t);
248 extern struct swap_info_struct *get_swap_info_struct(unsigned);
249 extern int can_share_swap_page(struct page *);
250 extern int remove_exclusive_swap_page(struct page *);
251 struct backing_dev_info;
253 extern spinlock_t swap_lock;
255 /* linux/mm/thrash.c */
256 extern struct mm_struct * swap_token_mm;
257 extern void grab_swap_token(void);
258 extern void __put_swap_token(struct mm_struct *);
260 static inline int has_swap_token(struct mm_struct *mm)
262 return (mm == swap_token_mm);
265 static inline void put_swap_token(struct mm_struct *mm)
267 if (has_swap_token(mm))
268 __put_swap_token(mm);
271 static inline void disable_swap_token(void)
273 put_swap_token(swap_token_mm);
276 #else /* CONFIG_SWAP */
278 #define total_swap_pages 0
279 #define total_swapcache_pages 0UL
281 #define si_swapinfo(val) \
282 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
283 /* only sparc can not include linux/pagemap.h in this file
284 * so leave page_cache_release and release_pages undeclared... */
285 #define free_page_and_swap_cache(page) \
286 page_cache_release(page)
287 #define free_pages_and_swap_cache(pages, nr) \
288 release_pages((pages), (nr), 0);
290 static inline void show_swap_cache_info(void)
294 static inline void free_swap_and_cache(swp_entry_t swp)
298 static inline int swap_duplicate(swp_entry_t swp)
303 static inline void swap_free(swp_entry_t swp)
307 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
308 struct vm_area_struct *vma, unsigned long addr)
313 static inline struct page *lookup_swap_cache(swp_entry_t swp)
318 #define can_share_swap_page(p) (page_mapcount(p) == 1)
320 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
326 static inline void __delete_from_swap_cache(struct page *page)
330 static inline void delete_from_swap_cache(struct page *page)
334 #define swap_token_default_timeout 0
336 static inline int remove_exclusive_swap_page(struct page *p)
341 static inline swp_entry_t get_swap_page(void)
348 /* linux/mm/thrash.c */
349 #define put_swap_token(x) do { } while(0)
350 #define grab_swap_token() do { } while(0)
351 #define has_swap_token(x) 0
352 #define disable_swap_token() do { } while(0)
354 #endif /* CONFIG_SWAP */
355 #endif /* __KERNEL__*/
356 #endif /* _LINUX_SWAP_H */