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 lru_cache_add_active_or_unevictable(struct page *,
177 struct vm_area_struct *);
178 extern void activate_page(struct page *);
179 extern void mark_page_accessed(struct page *);
180 extern void lru_add_drain(void);
181 extern int lru_add_drain_all(void);
182 extern void rotate_reclaimable_page(struct page *page);
183 extern void swap_setup(void);
185 extern void add_page_to_unevictable_list(struct page *page);
188 * lru_cache_add: add a page to the page lists
189 * @page: the page to add
191 static inline void lru_cache_add_anon(struct page *page)
193 __lru_cache_add(page, LRU_INACTIVE_ANON);
196 static inline void lru_cache_add_active_anon(struct page *page)
198 __lru_cache_add(page, LRU_ACTIVE_ANON);
201 static inline void lru_cache_add_file(struct page *page)
203 __lru_cache_add(page, LRU_INACTIVE_FILE);
206 static inline void lru_cache_add_active_file(struct page *page)
208 __lru_cache_add(page, LRU_ACTIVE_FILE);
211 /* linux/mm/vmscan.c */
212 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
214 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
216 extern int __isolate_lru_page(struct page *page, int mode, int file);
217 extern unsigned long shrink_all_memory(unsigned long nr_pages);
218 extern int vm_swappiness;
219 extern int remove_mapping(struct address_space *mapping, struct page *page);
220 extern long vm_total_pages;
223 extern int zone_reclaim_mode;
224 extern int sysctl_min_unmapped_ratio;
225 extern int sysctl_min_slab_ratio;
226 extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
228 #define zone_reclaim_mode 0
229 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
235 #ifdef CONFIG_UNEVICTABLE_LRU
236 extern int page_evictable(struct page *page, struct vm_area_struct *vma);
237 extern void scan_mapping_unevictable_pages(struct address_space *);
239 static inline int page_evictable(struct page *page,
240 struct vm_area_struct *vma)
244 static inline void scan_mapping_unevictable_pages(struct address_space *mapping)
249 extern int kswapd_run(int nid);
252 /* linux/mm/shmem.c */
253 extern int shmem_unuse(swp_entry_t entry, struct page *page);
254 #endif /* CONFIG_MMU */
256 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);
259 /* linux/mm/page_io.c */
260 extern int swap_readpage(struct file *, struct page *);
261 extern int swap_writepage(struct page *page, struct writeback_control *wbc);
262 extern void end_swap_bio_read(struct bio *bio, int err);
264 /* linux/mm/swap_state.c */
265 extern struct address_space swapper_space;
266 #define total_swapcache_pages swapper_space.nrpages
267 extern void show_swap_cache_info(void);
268 extern int add_to_swap(struct page *, gfp_t);
269 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
270 extern void __delete_from_swap_cache(struct page *);
271 extern void delete_from_swap_cache(struct page *);
272 extern void free_page_and_swap_cache(struct page *);
273 extern void free_pages_and_swap_cache(struct page **, int);
274 extern struct page *lookup_swap_cache(swp_entry_t);
275 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
276 struct vm_area_struct *vma, unsigned long addr);
277 extern struct page *swapin_readahead(swp_entry_t, gfp_t,
278 struct vm_area_struct *vma, unsigned long addr);
280 /* linux/mm/swapfile.c */
281 extern long total_swap_pages;
282 extern void si_swapinfo(struct sysinfo *);
283 extern swp_entry_t get_swap_page(void);
284 extern swp_entry_t get_swap_page_of_type(int);
285 extern int swap_duplicate(swp_entry_t);
286 extern int valid_swaphandles(swp_entry_t, unsigned long *);
287 extern void swap_free(swp_entry_t);
288 extern void free_swap_and_cache(swp_entry_t);
289 extern int swap_type_of(dev_t, sector_t, struct block_device **);
290 extern unsigned int count_swap_pages(int, int);
291 extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
292 extern sector_t swapdev_block(int, pgoff_t);
293 extern struct swap_info_struct *get_swap_info_struct(unsigned);
294 extern int can_share_swap_page(struct page *);
295 extern int remove_exclusive_swap_page(struct page *);
296 extern int remove_exclusive_swap_page_ref(struct page *);
297 struct backing_dev_info;
299 /* linux/mm/thrash.c */
300 extern struct mm_struct * swap_token_mm;
301 extern void grab_swap_token(void);
302 extern void __put_swap_token(struct mm_struct *);
304 static inline int has_swap_token(struct mm_struct *mm)
306 return (mm == swap_token_mm);
309 static inline void put_swap_token(struct mm_struct *mm)
311 if (has_swap_token(mm))
312 __put_swap_token(mm);
315 static inline void disable_swap_token(void)
317 put_swap_token(swap_token_mm);
320 #else /* CONFIG_SWAP */
322 #define total_swap_pages 0
323 #define total_swapcache_pages 0UL
325 #define si_swapinfo(val) \
326 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
327 /* only sparc can not include linux/pagemap.h in this file
328 * so leave page_cache_release and release_pages undeclared... */
329 #define free_page_and_swap_cache(page) \
330 page_cache_release(page)
331 #define free_pages_and_swap_cache(pages, nr) \
332 release_pages((pages), (nr), 0);
334 static inline void show_swap_cache_info(void)
338 static inline void free_swap_and_cache(swp_entry_t swp)
342 static inline int swap_duplicate(swp_entry_t swp)
347 static inline void swap_free(swp_entry_t swp)
351 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
352 struct vm_area_struct *vma, unsigned long addr)
357 static inline struct page *lookup_swap_cache(swp_entry_t swp)
362 #define can_share_swap_page(p) (page_mapcount(p) == 1)
364 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
370 static inline void __delete_from_swap_cache(struct page *page)
374 static inline void delete_from_swap_cache(struct page *page)
378 #define swap_token_default_timeout 0
380 static inline int remove_exclusive_swap_page(struct page *p)
385 static inline int remove_exclusive_swap_page_ref(struct page *page)
390 static inline swp_entry_t get_swap_page(void)
397 /* linux/mm/thrash.c */
398 #define put_swap_token(x) do { } while(0)
399 #define grab_swap_token() do { } while(0)
400 #define has_swap_token(x) 0
401 #define disable_swap_token() do { } while(0)
403 #endif /* CONFIG_SWAP */
404 #endif /* __KERNEL__*/
405 #endif /* _LINUX_SWAP_H */