4 #include <linux/config.h>
5 #include <linux/spinlock.h>
6 #include <linux/linkage.h>
7 #include <linux/mmzone.h>
8 #include <linux/list.h>
9 #include <linux/sched.h>
11 #include <asm/atomic.h>
14 #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
15 #define SWAP_FLAG_PRIO_MASK 0x7fff
16 #define SWAP_FLAG_PRIO_SHIFT 0
18 static inline int current_is_kswapd(void)
20 return current->flags & PF_KSWAPD;
24 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
25 * be swapped to. The swap type and the offset into that swap type are
26 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits
27 * for the type means that the maximum number of swapcache pages is 27 bits
28 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
29 * the type/offset into the pte as 5/27 as well.
31 #define MAX_SWAPFILES_SHIFT 5
32 #define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
35 * Magic header for a swap area. The first part of the union is
36 * what the swap magic looks like for the old (limited to 128MB)
37 * swap area format, the second part of the union adds - in the
38 * old reserved area - some extra information. Note that the first
39 * kilobyte is reserved for boot loader or disk label stuff...
41 * Having the magic at the end of the PAGE_SIZE makes detecting swap
42 * areas somewhat tricky on machines that support multiple page sizes.
43 * For 2.5 we'll probably want to move the magic to just beyond the
48 char reserved[PAGE_SIZE - 10];
49 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
52 char bootbits[1024]; /* Space for disklabel etc. */
54 unsigned int last_page;
55 unsigned int nr_badpages;
56 unsigned int padding[125];
57 unsigned int badpages[1];
61 /* A swap entry has to fit into a "unsigned long", as
62 * the entry is hidden in the "index" field of the
63 * swapper address space.
70 * current->reclaim_state points to one of these when a task is running
73 struct reclaim_state {
74 unsigned long reclaimed_slab;
81 struct writeback_control;
85 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
86 * disk blocks. A list of swap extents maps the entire swapfile. (Where the
87 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
88 * from setup, they're handled identically.
90 * We always assume that blocks are of size PAGE_SIZE.
93 struct list_head list;
100 * Max bad pages in the new format..
102 #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
103 #define MAX_SWAP_BADPAGES \
104 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
107 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
108 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
109 SWP_ACTIVE = (SWP_USED | SWP_WRITEOK),
110 /* add others here before... */
111 SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
114 #define SWAP_CLUSTER_MAX 32
116 #define SWAP_MAP_MAX 0x7fff
117 #define SWAP_MAP_BAD 0x8000
120 * The in-memory structure used to track swap areas.
122 struct swap_info_struct {
124 int prio; /* swap priority */
125 struct file *swap_file;
126 struct block_device *bdev;
127 struct list_head extent_list;
128 struct swap_extent *curr_swap_extent;
129 unsigned old_block_size;
130 unsigned short * swap_map;
131 unsigned int lowest_bit;
132 unsigned int highest_bit;
133 unsigned int cluster_next;
134 unsigned int cluster_nr;
137 unsigned int inuse_pages;
138 int next; /* next entry on swap list */
142 int head; /* head of priority-ordered swapfile list */
143 int next; /* swapfile to be used next */
146 /* Swap 50% full? Release swapcache more aggressively.. */
147 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
149 /* linux/mm/oom_kill.c */
150 extern void out_of_memory(gfp_t gfp_mask, int order);
152 /* linux/mm/memory.c */
153 extern void swapin_readahead(swp_entry_t, unsigned long, struct vm_area_struct *);
155 /* linux/mm/page_alloc.c */
156 extern unsigned long totalram_pages;
157 extern unsigned long totalhigh_pages;
158 extern long nr_swap_pages;
159 extern unsigned int nr_free_pages(void);
160 extern unsigned int nr_free_pages_pgdat(pg_data_t *pgdat);
161 extern unsigned int nr_free_buffer_pages(void);
162 extern unsigned int nr_free_pagecache_pages(void);
164 /* linux/mm/swap.c */
165 extern void FASTCALL(lru_cache_add(struct page *));
166 extern void FASTCALL(lru_cache_add_active(struct page *));
167 extern void FASTCALL(activate_page(struct page *));
168 extern void FASTCALL(mark_page_accessed(struct page *));
169 extern void lru_add_drain(void);
170 extern int lru_add_drain_all(void);
171 extern int rotate_reclaimable_page(struct page *page);
172 extern void swap_setup(void);
174 /* linux/mm/vmscan.c */
175 extern int try_to_free_pages(struct zone **, gfp_t);
176 extern int shrink_all_memory(int);
177 extern int vm_swappiness;
180 extern int zone_reclaim_mode;
181 extern int zone_reclaim_interval;
182 extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
184 #define zone_reclaim_mode 0
185 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
191 #ifdef CONFIG_MIGRATION
192 extern int isolate_lru_page(struct page *p);
193 extern int putback_lru_pages(struct list_head *l);
194 extern int migrate_pages(struct list_head *l, struct list_head *t,
195 struct list_head *moved, struct list_head *failed);
197 static inline int isolate_lru_page(struct page *p) { return -ENOSYS; }
198 static inline int putback_lru_pages(struct list_head *l) { return 0; }
199 static inline int migrate_pages(struct list_head *l, struct list_head *t,
200 struct list_head *moved, struct list_head *failed) { return -ENOSYS; }
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 struct swap_info_struct swap_info[];
235 extern void si_swapinfo(struct sysinfo *);
236 extern swp_entry_t get_swap_page(void);
237 extern swp_entry_t get_swap_page_of_type(int type);
238 extern int swap_duplicate(swp_entry_t);
239 extern int valid_swaphandles(swp_entry_t, unsigned long *);
240 extern void swap_free(swp_entry_t);
241 extern void free_swap_and_cache(swp_entry_t);
242 extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
243 extern struct swap_info_struct *get_swap_info_struct(unsigned);
244 extern int can_share_swap_page(struct page *);
245 extern int remove_exclusive_swap_page(struct page *);
246 struct backing_dev_info;
248 extern spinlock_t swap_lock;
250 /* linux/mm/thrash.c */
251 extern struct mm_struct * swap_token_mm;
252 extern unsigned long swap_token_default_timeout;
253 extern void grab_swap_token(void);
254 extern void __put_swap_token(struct mm_struct *);
256 static inline int has_swap_token(struct mm_struct *mm)
258 return (mm == swap_token_mm);
261 static inline void put_swap_token(struct mm_struct *mm)
263 if (has_swap_token(mm))
264 __put_swap_token(mm);
267 static inline void disable_swap_token(void)
269 put_swap_token(swap_token_mm);
272 #else /* CONFIG_SWAP */
274 #define total_swap_pages 0
275 #define total_swapcache_pages 0UL
277 #define si_swapinfo(val) \
278 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
279 /* only sparc can not include linux/pagemap.h in this file
280 * so leave page_cache_release and release_pages undeclared... */
281 #define free_page_and_swap_cache(page) \
282 page_cache_release(page)
283 #define free_pages_and_swap_cache(pages, nr) \
284 release_pages((pages), (nr), 0);
286 #define show_swap_cache_info() /*NOTHING*/
287 #define free_swap_and_cache(swp) /*NOTHING*/
288 #define swap_duplicate(swp) /*NOTHING*/
289 #define swap_free(swp) /*NOTHING*/
290 #define read_swap_cache_async(swp,vma,addr) NULL
291 #define lookup_swap_cache(swp) NULL
292 #define valid_swaphandles(swp, off) 0
293 #define can_share_swap_page(p) 0
294 #define move_to_swap_cache(p, swp) 1
295 #define move_from_swap_cache(p, i, m) 1
296 #define __delete_from_swap_cache(p) /*NOTHING*/
297 #define delete_from_swap_cache(p) /*NOTHING*/
298 #define swap_token_default_timeout 0
300 static inline int remove_exclusive_swap_page(struct page *p)
305 static inline swp_entry_t get_swap_page(void)
312 /* linux/mm/thrash.c */
313 #define put_swap_token(x) do { } while(0)
314 #define grab_swap_token() do { } while(0)
315 #define has_swap_token(x) 0
316 #define disable_swap_token() do { } while(0)
318 #endif /* CONFIG_SWAP */
319 #endif /* __KERNEL__*/
320 #endif /* _LINUX_SWAP_H */