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_anon(struct page *page)
189 __lru_cache_add(page, LRU_INACTIVE_ANON);
192 static inline void lru_cache_add_active_anon(struct page *page)
194 __lru_cache_add(page, LRU_ACTIVE_ANON);
197 static inline void lru_cache_add_file(struct page *page)
199 __lru_cache_add(page, LRU_INACTIVE_FILE);
202 static inline void lru_cache_add_active_file(struct page *page)
204 __lru_cache_add(page, LRU_ACTIVE_FILE);
207 /* linux/mm/vmscan.c */
208 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
210 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
212 extern int __isolate_lru_page(struct page *page, int mode, int file);
213 extern unsigned long shrink_all_memory(unsigned long nr_pages);
214 extern int vm_swappiness;
215 extern int remove_mapping(struct address_space *mapping, struct page *page);
216 extern long vm_total_pages;
219 extern int zone_reclaim_mode;
220 extern int sysctl_min_unmapped_ratio;
221 extern int sysctl_min_slab_ratio;
222 extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
224 #define zone_reclaim_mode 0
225 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
231 extern int kswapd_run(int nid);
234 /* linux/mm/shmem.c */
235 extern int shmem_unuse(swp_entry_t entry, struct page *page);
236 #endif /* CONFIG_MMU */
238 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);
241 /* linux/mm/page_io.c */
242 extern int swap_readpage(struct file *, struct page *);
243 extern int swap_writepage(struct page *page, struct writeback_control *wbc);
244 extern void end_swap_bio_read(struct bio *bio, int err);
246 /* linux/mm/swap_state.c */
247 extern struct address_space swapper_space;
248 #define total_swapcache_pages swapper_space.nrpages
249 extern void show_swap_cache_info(void);
250 extern int add_to_swap(struct page *, gfp_t);
251 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
252 extern void __delete_from_swap_cache(struct page *);
253 extern void delete_from_swap_cache(struct page *);
254 extern void free_page_and_swap_cache(struct page *);
255 extern void free_pages_and_swap_cache(struct page **, int);
256 extern struct page *lookup_swap_cache(swp_entry_t);
257 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
258 struct vm_area_struct *vma, unsigned long addr);
259 extern struct page *swapin_readahead(swp_entry_t, gfp_t,
260 struct vm_area_struct *vma, unsigned long addr);
262 /* linux/mm/swapfile.c */
263 extern long total_swap_pages;
264 extern void si_swapinfo(struct sysinfo *);
265 extern swp_entry_t get_swap_page(void);
266 extern swp_entry_t get_swap_page_of_type(int);
267 extern int swap_duplicate(swp_entry_t);
268 extern int valid_swaphandles(swp_entry_t, unsigned long *);
269 extern void swap_free(swp_entry_t);
270 extern void free_swap_and_cache(swp_entry_t);
271 extern int swap_type_of(dev_t, sector_t, struct block_device **);
272 extern unsigned int count_swap_pages(int, int);
273 extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
274 extern sector_t swapdev_block(int, pgoff_t);
275 extern struct swap_info_struct *get_swap_info_struct(unsigned);
276 extern int can_share_swap_page(struct page *);
277 extern int remove_exclusive_swap_page(struct page *);
278 extern int remove_exclusive_swap_page_ref(struct page *);
279 struct backing_dev_info;
281 /* linux/mm/thrash.c */
282 extern struct mm_struct * swap_token_mm;
283 extern void grab_swap_token(void);
284 extern void __put_swap_token(struct mm_struct *);
286 static inline int has_swap_token(struct mm_struct *mm)
288 return (mm == swap_token_mm);
291 static inline void put_swap_token(struct mm_struct *mm)
293 if (has_swap_token(mm))
294 __put_swap_token(mm);
297 static inline void disable_swap_token(void)
299 put_swap_token(swap_token_mm);
302 #else /* CONFIG_SWAP */
304 #define total_swap_pages 0
305 #define total_swapcache_pages 0UL
307 #define si_swapinfo(val) \
308 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
309 /* only sparc can not include linux/pagemap.h in this file
310 * so leave page_cache_release and release_pages undeclared... */
311 #define free_page_and_swap_cache(page) \
312 page_cache_release(page)
313 #define free_pages_and_swap_cache(pages, nr) \
314 release_pages((pages), (nr), 0);
316 static inline void show_swap_cache_info(void)
320 static inline void free_swap_and_cache(swp_entry_t swp)
324 static inline int swap_duplicate(swp_entry_t swp)
329 static inline void swap_free(swp_entry_t swp)
333 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
334 struct vm_area_struct *vma, unsigned long addr)
339 static inline struct page *lookup_swap_cache(swp_entry_t swp)
344 #define can_share_swap_page(p) (page_mapcount(p) == 1)
346 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
352 static inline void __delete_from_swap_cache(struct page *page)
356 static inline void delete_from_swap_cache(struct page *page)
360 #define swap_token_default_timeout 0
362 static inline int remove_exclusive_swap_page(struct page *p)
367 static inline int remove_exclusive_swap_page_ref(struct page *page)
372 static inline swp_entry_t get_swap_page(void)
379 /* linux/mm/thrash.c */
380 #define put_swap_token(x) do { } while(0)
381 #define grab_swap_token() do { } while(0)
382 #define has_swap_token(x) 0
383 #define disable_swap_token() do { } while(0)
385 #endif /* CONFIG_SWAP */
386 #endif /* __KERNEL__*/
387 #endif /* _LINUX_SWAP_H */