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1da177e4 LT |
1 | #ifndef _LINUX_SWAP_H |
2 | #define _LINUX_SWAP_H | |
3 | ||
1da177e4 LT |
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> | |
542d1c88 | 9 | |
1da177e4 LT |
10 | #include <asm/atomic.h> |
11 | #include <asm/page.h> | |
12 | ||
8bc719d3 MS |
13 | struct notifier_block; |
14 | ||
1da177e4 LT |
15 | #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */ |
16 | #define SWAP_FLAG_PRIO_MASK 0x7fff | |
17 | #define SWAP_FLAG_PRIO_SHIFT 0 | |
18 | ||
19 | static inline int current_is_kswapd(void) | |
20 | { | |
21 | return current->flags & PF_KSWAPD; | |
22 | } | |
23 | ||
24 | /* | |
25 | * MAX_SWAPFILES defines the maximum number of swaptypes: things which can | |
26 | * be swapped to. The swap type and the offset into that swap type are | |
27 | * encoded into pte's and into pgoff_t's in the swapcache. Using five bits | |
28 | * for the type means that the maximum number of swapcache pages is 27 bits | |
29 | * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs | |
30 | * the type/offset into the pte as 5/27 as well. | |
31 | */ | |
32 | #define MAX_SWAPFILES_SHIFT 5 | |
0697212a | 33 | #ifndef CONFIG_MIGRATION |
1da177e4 | 34 | #define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT) |
0697212a CL |
35 | #else |
36 | /* Use last two entries for page migration swap entries */ | |
37 | #define MAX_SWAPFILES ((1 << MAX_SWAPFILES_SHIFT)-2) | |
38 | #define SWP_MIGRATION_READ MAX_SWAPFILES | |
39 | #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + 1) | |
40 | #endif | |
1da177e4 LT |
41 | |
42 | /* | |
43 | * Magic header for a swap area. The first part of the union is | |
44 | * what the swap magic looks like for the old (limited to 128MB) | |
45 | * swap area format, the second part of the union adds - in the | |
46 | * old reserved area - some extra information. Note that the first | |
47 | * kilobyte is reserved for boot loader or disk label stuff... | |
48 | * | |
49 | * Having the magic at the end of the PAGE_SIZE makes detecting swap | |
50 | * areas somewhat tricky on machines that support multiple page sizes. | |
51 | * For 2.5 we'll probably want to move the magic to just beyond the | |
52 | * bootbits... | |
53 | */ | |
54 | union swap_header { | |
55 | struct { | |
56 | char reserved[PAGE_SIZE - 10]; | |
57 | char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */ | |
58 | } magic; | |
59 | struct { | |
e8f03d02 AD |
60 | char bootbits[1024]; /* Space for disklabel etc. */ |
61 | __u32 version; | |
62 | __u32 last_page; | |
63 | __u32 nr_badpages; | |
64 | unsigned char sws_uuid[16]; | |
65 | unsigned char sws_volume[16]; | |
66 | __u32 padding[117]; | |
67 | __u32 badpages[1]; | |
1da177e4 LT |
68 | } info; |
69 | }; | |
70 | ||
71 | /* A swap entry has to fit into a "unsigned long", as | |
72 | * the entry is hidden in the "index" field of the | |
73 | * swapper address space. | |
74 | */ | |
75 | typedef struct { | |
76 | unsigned long val; | |
77 | } swp_entry_t; | |
78 | ||
79 | /* | |
80 | * current->reclaim_state points to one of these when a task is running | |
81 | * memory reclaim | |
82 | */ | |
83 | struct reclaim_state { | |
84 | unsigned long reclaimed_slab; | |
85 | }; | |
86 | ||
87 | #ifdef __KERNEL__ | |
88 | ||
89 | struct address_space; | |
90 | struct sysinfo; | |
91 | struct writeback_control; | |
92 | struct zone; | |
93 | ||
94 | /* | |
95 | * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of | |
96 | * disk blocks. A list of swap extents maps the entire swapfile. (Where the | |
97 | * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart | |
98 | * from setup, they're handled identically. | |
99 | * | |
100 | * We always assume that blocks are of size PAGE_SIZE. | |
101 | */ | |
102 | struct swap_extent { | |
103 | struct list_head list; | |
104 | pgoff_t start_page; | |
105 | pgoff_t nr_pages; | |
106 | sector_t start_block; | |
107 | }; | |
108 | ||
109 | /* | |
110 | * Max bad pages in the new format.. | |
111 | */ | |
112 | #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x) | |
113 | #define MAX_SWAP_BADPAGES \ | |
114 | ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int)) | |
115 | ||
116 | enum { | |
117 | SWP_USED = (1 << 0), /* is slot in swap_info[] used? */ | |
118 | SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */ | |
119 | SWP_ACTIVE = (SWP_USED | SWP_WRITEOK), | |
52b7efdb HD |
120 | /* add others here before... */ |
121 | SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */ | |
1da177e4 LT |
122 | }; |
123 | ||
124 | #define SWAP_CLUSTER_MAX 32 | |
125 | ||
126 | #define SWAP_MAP_MAX 0x7fff | |
127 | #define SWAP_MAP_BAD 0x8000 | |
128 | ||
129 | /* | |
130 | * The in-memory structure used to track swap areas. | |
1da177e4 LT |
131 | */ |
132 | struct swap_info_struct { | |
133 | unsigned int flags; | |
5d337b91 | 134 | int prio; /* swap priority */ |
1da177e4 LT |
135 | struct file *swap_file; |
136 | struct block_device *bdev; | |
137 | struct list_head extent_list; | |
1da177e4 LT |
138 | struct swap_extent *curr_swap_extent; |
139 | unsigned old_block_size; | |
140 | unsigned short * swap_map; | |
141 | unsigned int lowest_bit; | |
142 | unsigned int highest_bit; | |
143 | unsigned int cluster_next; | |
144 | unsigned int cluster_nr; | |
6eb396dc HD |
145 | unsigned int pages; |
146 | unsigned int max; | |
147 | unsigned int inuse_pages; | |
1da177e4 LT |
148 | int next; /* next entry on swap list */ |
149 | }; | |
150 | ||
151 | struct swap_list_t { | |
152 | int head; /* head of priority-ordered swapfile list */ | |
153 | int next; /* swapfile to be used next */ | |
154 | }; | |
155 | ||
156 | /* Swap 50% full? Release swapcache more aggressively.. */ | |
157 | #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages) | |
158 | ||
159 | /* linux/mm/oom_kill.c */ | |
9b0f8b04 | 160 | extern void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order); |
8bc719d3 MS |
161 | extern int register_oom_notifier(struct notifier_block *nb); |
162 | extern int unregister_oom_notifier(struct notifier_block *nb); | |
1da177e4 LT |
163 | |
164 | /* linux/mm/memory.c */ | |
165 | extern void swapin_readahead(swp_entry_t, unsigned long, struct vm_area_struct *); | |
166 | ||
167 | /* linux/mm/page_alloc.c */ | |
168 | extern unsigned long totalram_pages; | |
cb45b0e9 | 169 | extern unsigned long totalreserve_pages; |
1da177e4 LT |
170 | extern long nr_swap_pages; |
171 | extern unsigned int nr_free_pages(void); | |
172 | extern unsigned int nr_free_pages_pgdat(pg_data_t *pgdat); | |
173 | extern unsigned int nr_free_buffer_pages(void); | |
174 | extern unsigned int nr_free_pagecache_pages(void); | |
175 | ||
176 | /* linux/mm/swap.c */ | |
177 | extern void FASTCALL(lru_cache_add(struct page *)); | |
178 | extern void FASTCALL(lru_cache_add_active(struct page *)); | |
179 | extern void FASTCALL(activate_page(struct page *)); | |
180 | extern void FASTCALL(mark_page_accessed(struct page *)); | |
181 | extern void lru_add_drain(void); | |
053837fc | 182 | extern int lru_add_drain_all(void); |
1da177e4 LT |
183 | extern int rotate_reclaimable_page(struct page *page); |
184 | extern void swap_setup(void); | |
185 | ||
186 | /* linux/mm/vmscan.c */ | |
69e05944 AM |
187 | extern unsigned long try_to_free_pages(struct zone **, gfp_t); |
188 | extern unsigned long shrink_all_memory(unsigned long nr_pages); | |
1da177e4 | 189 | extern int vm_swappiness; |
b20a3503 | 190 | extern int remove_mapping(struct address_space *mapping, struct page *page); |
bd1e22b8 | 191 | extern long vm_total_pages; |
b20a3503 | 192 | |
9eeff239 CL |
193 | #ifdef CONFIG_NUMA |
194 | extern int zone_reclaim_mode; | |
9614634f | 195 | extern int sysctl_min_unmapped_ratio; |
9eeff239 CL |
196 | extern int zone_reclaim(struct zone *, gfp_t, unsigned int); |
197 | #else | |
198 | #define zone_reclaim_mode 0 | |
199 | static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order) | |
200 | { | |
201 | return 0; | |
202 | } | |
203 | #endif | |
204 | ||
3218ae14 YG |
205 | extern int kswapd_run(int nid); |
206 | ||
1da177e4 LT |
207 | #ifdef CONFIG_MMU |
208 | /* linux/mm/shmem.c */ | |
209 | extern int shmem_unuse(swp_entry_t entry, struct page *page); | |
210 | #endif /* CONFIG_MMU */ | |
211 | ||
212 | extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *); | |
213 | ||
214 | #ifdef CONFIG_SWAP | |
215 | /* linux/mm/page_io.c */ | |
216 | extern int swap_readpage(struct file *, struct page *); | |
217 | extern int swap_writepage(struct page *page, struct writeback_control *wbc); | |
218 | extern int rw_swap_page_sync(int, swp_entry_t, struct page *); | |
219 | ||
220 | /* linux/mm/swap_state.c */ | |
221 | extern struct address_space swapper_space; | |
222 | #define total_swapcache_pages swapper_space.nrpages | |
223 | extern void show_swap_cache_info(void); | |
1480a540 | 224 | extern int add_to_swap(struct page *, gfp_t); |
1da177e4 LT |
225 | extern void __delete_from_swap_cache(struct page *); |
226 | extern void delete_from_swap_cache(struct page *); | |
227 | extern int move_to_swap_cache(struct page *, swp_entry_t); | |
228 | extern int move_from_swap_cache(struct page *, unsigned long, | |
229 | struct address_space *); | |
230 | extern void free_page_and_swap_cache(struct page *); | |
231 | extern void free_pages_and_swap_cache(struct page **, int); | |
232 | extern struct page * lookup_swap_cache(swp_entry_t); | |
233 | extern struct page * read_swap_cache_async(swp_entry_t, struct vm_area_struct *vma, | |
234 | unsigned long addr); | |
235 | /* linux/mm/swapfile.c */ | |
236 | extern long total_swap_pages; | |
237 | extern unsigned int nr_swapfiles; | |
1da177e4 LT |
238 | extern void si_swapinfo(struct sysinfo *); |
239 | extern swp_entry_t get_swap_page(void); | |
f577eb30 | 240 | extern swp_entry_t get_swap_page_of_type(int); |
1da177e4 LT |
241 | extern int swap_duplicate(swp_entry_t); |
242 | extern int valid_swaphandles(swp_entry_t, unsigned long *); | |
243 | extern void swap_free(swp_entry_t); | |
244 | extern void free_swap_and_cache(swp_entry_t); | |
f577eb30 RW |
245 | extern int swap_type_of(dev_t); |
246 | extern unsigned int count_swap_pages(int, int); | |
1da177e4 LT |
247 | extern sector_t map_swap_page(struct swap_info_struct *, 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; | |
252 | ||
5d337b91 | 253 | extern spinlock_t swap_lock; |
1da177e4 LT |
254 | |
255 | /* linux/mm/thrash.c */ | |
256 | extern struct mm_struct * swap_token_mm; | |
257 | extern unsigned long swap_token_default_timeout; | |
258 | extern void grab_swap_token(void); | |
259 | extern void __put_swap_token(struct mm_struct *); | |
260 | ||
261 | static inline int has_swap_token(struct mm_struct *mm) | |
262 | { | |
263 | return (mm == swap_token_mm); | |
264 | } | |
265 | ||
266 | static inline void put_swap_token(struct mm_struct *mm) | |
267 | { | |
268 | if (has_swap_token(mm)) | |
269 | __put_swap_token(mm); | |
270 | } | |
271 | ||
f7b7fd8f RR |
272 | static inline void disable_swap_token(void) |
273 | { | |
274 | put_swap_token(swap_token_mm); | |
275 | } | |
276 | ||
1da177e4 LT |
277 | #else /* CONFIG_SWAP */ |
278 | ||
279 | #define total_swap_pages 0 | |
280 | #define total_swapcache_pages 0UL | |
281 | ||
282 | #define si_swapinfo(val) \ | |
283 | do { (val)->freeswap = (val)->totalswap = 0; } while (0) | |
9ae5b3c7 OH |
284 | /* only sparc can not include linux/pagemap.h in this file |
285 | * so leave page_cache_release and release_pages undeclared... */ | |
1da177e4 LT |
286 | #define free_page_and_swap_cache(page) \ |
287 | page_cache_release(page) | |
288 | #define free_pages_and_swap_cache(pages, nr) \ | |
289 | release_pages((pages), (nr), 0); | |
290 | ||
bd96b9eb CK |
291 | static inline void show_swap_cache_info(void) |
292 | { | |
293 | } | |
294 | ||
295 | static inline void free_swap_and_cache(swp_entry_t swp) | |
296 | { | |
297 | } | |
298 | ||
299 | static inline int swap_duplicate(swp_entry_t swp) | |
300 | { | |
301 | return 0; | |
302 | } | |
303 | ||
304 | static inline void swap_free(swp_entry_t swp) | |
305 | { | |
306 | } | |
307 | ||
308 | static inline struct page *read_swap_cache_async(swp_entry_t swp, | |
309 | struct vm_area_struct *vma, unsigned long addr) | |
310 | { | |
311 | return NULL; | |
312 | } | |
313 | ||
314 | static inline struct page *lookup_swap_cache(swp_entry_t swp) | |
315 | { | |
316 | return NULL; | |
317 | } | |
318 | ||
319 | static inline int valid_swaphandles(swp_entry_t entry, unsigned long *offset) | |
320 | { | |
321 | return 0; | |
322 | } | |
323 | ||
e6333fd4 | 324 | #define can_share_swap_page(p) (page_mapcount(p) == 1) |
bd96b9eb CK |
325 | |
326 | static inline int move_to_swap_cache(struct page *page, swp_entry_t entry) | |
327 | { | |
328 | return 1; | |
329 | } | |
330 | ||
331 | static inline int move_from_swap_cache(struct page *page, unsigned long index, | |
332 | struct address_space *mapping) | |
333 | { | |
334 | return 1; | |
335 | } | |
336 | ||
337 | static inline void __delete_from_swap_cache(struct page *page) | |
338 | { | |
339 | } | |
340 | ||
341 | static inline void delete_from_swap_cache(struct page *page) | |
342 | { | |
343 | } | |
344 | ||
1da177e4 LT |
345 | #define swap_token_default_timeout 0 |
346 | ||
347 | static inline int remove_exclusive_swap_page(struct page *p) | |
348 | { | |
349 | return 0; | |
350 | } | |
351 | ||
352 | static inline swp_entry_t get_swap_page(void) | |
353 | { | |
354 | swp_entry_t entry; | |
355 | entry.val = 0; | |
356 | return entry; | |
357 | } | |
358 | ||
359 | /* linux/mm/thrash.c */ | |
360 | #define put_swap_token(x) do { } while(0) | |
361 | #define grab_swap_token() do { } while(0) | |
362 | #define has_swap_token(x) 0 | |
f7b7fd8f | 363 | #define disable_swap_token() do { } while(0) |
1da177e4 LT |
364 | |
365 | #endif /* CONFIG_SWAP */ | |
366 | #endif /* __KERNEL__*/ | |
367 | #endif /* _LINUX_SWAP_H */ |