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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> | |
66e1707b | 8 | #include <linux/memcontrol.h> |
1da177e4 | 9 | #include <linux/sched.h> |
542d1c88 | 10 | |
1da177e4 LT |
11 | #include <asm/atomic.h> |
12 | #include <asm/page.h> | |
13 | ||
8bc719d3 MS |
14 | struct notifier_block; |
15 | ||
ab954160 AM |
16 | struct bio; |
17 | ||
1da177e4 LT |
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 | |
21 | ||
22 | static inline int current_is_kswapd(void) | |
23 | { | |
24 | return current->flags & PF_KSWAPD; | |
25 | } | |
26 | ||
27 | /* | |
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. | |
34 | */ | |
35 | #define MAX_SWAPFILES_SHIFT 5 | |
0697212a | 36 | #ifndef CONFIG_MIGRATION |
1da177e4 | 37 | #define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT) |
0697212a CL |
38 | #else |
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) | |
43 | #endif | |
1da177e4 LT |
44 | |
45 | /* | |
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... | |
51 | * | |
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 | |
55 | * bootbits... | |
56 | */ | |
57 | union swap_header { | |
58 | struct { | |
59 | char reserved[PAGE_SIZE - 10]; | |
60 | char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */ | |
61 | } magic; | |
62 | struct { | |
e8f03d02 AD |
63 | char bootbits[1024]; /* Space for disklabel etc. */ |
64 | __u32 version; | |
65 | __u32 last_page; | |
66 | __u32 nr_badpages; | |
67 | unsigned char sws_uuid[16]; | |
68 | unsigned char sws_volume[16]; | |
69 | __u32 padding[117]; | |
70 | __u32 badpages[1]; | |
1da177e4 LT |
71 | } info; |
72 | }; | |
73 | ||
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. | |
77 | */ | |
78 | typedef struct { | |
79 | unsigned long val; | |
80 | } swp_entry_t; | |
81 | ||
82 | /* | |
83 | * current->reclaim_state points to one of these when a task is running | |
84 | * memory reclaim | |
85 | */ | |
86 | struct reclaim_state { | |
87 | unsigned long reclaimed_slab; | |
88 | }; | |
89 | ||
90 | #ifdef __KERNEL__ | |
91 | ||
92 | struct address_space; | |
93 | struct sysinfo; | |
94 | struct writeback_control; | |
95 | struct zone; | |
96 | ||
97 | /* | |
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. | |
102 | * | |
103 | * We always assume that blocks are of size PAGE_SIZE. | |
104 | */ | |
105 | struct swap_extent { | |
106 | struct list_head list; | |
107 | pgoff_t start_page; | |
108 | pgoff_t nr_pages; | |
109 | sector_t start_block; | |
110 | }; | |
111 | ||
112 | /* | |
113 | * Max bad pages in the new format.. | |
114 | */ | |
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)) | |
118 | ||
119 | enum { | |
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), | |
52b7efdb HD |
123 | /* add others here before... */ |
124 | SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */ | |
1da177e4 LT |
125 | }; |
126 | ||
127 | #define SWAP_CLUSTER_MAX 32 | |
128 | ||
129 | #define SWAP_MAP_MAX 0x7fff | |
130 | #define SWAP_MAP_BAD 0x8000 | |
131 | ||
132 | /* | |
133 | * The in-memory structure used to track swap areas. | |
1da177e4 LT |
134 | */ |
135 | struct swap_info_struct { | |
136 | unsigned int flags; | |
5d337b91 | 137 | int prio; /* swap priority */ |
1da177e4 LT |
138 | struct file *swap_file; |
139 | struct block_device *bdev; | |
140 | struct list_head extent_list; | |
1da177e4 LT |
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; | |
6eb396dc HD |
148 | unsigned int pages; |
149 | unsigned int max; | |
150 | unsigned int inuse_pages; | |
1da177e4 LT |
151 | int next; /* next entry on swap list */ |
152 | }; | |
153 | ||
154 | struct swap_list_t { | |
155 | int head; /* head of priority-ordered swapfile list */ | |
156 | int next; /* swapfile to be used next */ | |
157 | }; | |
158 | ||
159 | /* Swap 50% full? Release swapcache more aggressively.. */ | |
160 | #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages) | |
161 | ||
1da177e4 LT |
162 | /* linux/mm/page_alloc.c */ |
163 | extern unsigned long totalram_pages; | |
cb45b0e9 | 164 | extern unsigned long totalreserve_pages; |
1da177e4 | 165 | extern long nr_swap_pages; |
1da177e4 LT |
166 | extern unsigned int nr_free_buffer_pages(void); |
167 | extern unsigned int nr_free_pagecache_pages(void); | |
168 | ||
96177299 CL |
169 | /* Definition of global_page_state not available yet */ |
170 | #define nr_free_pages() global_page_state(NR_FREE_PAGES) | |
171 | ||
172 | ||
1da177e4 | 173 | /* linux/mm/swap.c */ |
b3c97528 HH |
174 | extern void lru_cache_add(struct page *); |
175 | extern void lru_cache_add_active(struct page *); | |
176 | extern void activate_page(struct page *); | |
177 | extern void mark_page_accessed(struct page *); | |
1da177e4 | 178 | extern void lru_add_drain(void); |
053837fc | 179 | extern int lru_add_drain_all(void); |
ac6aadb2 | 180 | extern void rotate_reclaimable_page(struct page *page); |
1da177e4 LT |
181 | extern void swap_setup(void); |
182 | ||
183 | /* linux/mm/vmscan.c */ | |
dac1d27b | 184 | extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, |
5ad333eb | 185 | gfp_t gfp_mask); |
e1a1cd59 BS |
186 | extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem, |
187 | gfp_t gfp_mask); | |
66e1707b | 188 | extern int __isolate_lru_page(struct page *page, int mode); |
69e05944 | 189 | extern unsigned long shrink_all_memory(unsigned long nr_pages); |
1da177e4 | 190 | extern int vm_swappiness; |
b20a3503 | 191 | extern int remove_mapping(struct address_space *mapping, struct page *page); |
bd1e22b8 | 192 | extern long vm_total_pages; |
b20a3503 | 193 | |
9eeff239 CL |
194 | #ifdef CONFIG_NUMA |
195 | extern int zone_reclaim_mode; | |
9614634f | 196 | extern int sysctl_min_unmapped_ratio; |
0ff38490 | 197 | extern int sysctl_min_slab_ratio; |
9eeff239 CL |
198 | extern int zone_reclaim(struct zone *, gfp_t, unsigned int); |
199 | #else | |
200 | #define zone_reclaim_mode 0 | |
201 | static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order) | |
202 | { | |
203 | return 0; | |
204 | } | |
205 | #endif | |
206 | ||
3218ae14 YG |
207 | extern int kswapd_run(int nid); |
208 | ||
1da177e4 LT |
209 | #ifdef CONFIG_MMU |
210 | /* linux/mm/shmem.c */ | |
211 | extern int shmem_unuse(swp_entry_t entry, struct page *page); | |
212 | #endif /* CONFIG_MMU */ | |
213 | ||
214 | extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *); | |
215 | ||
216 | #ifdef CONFIG_SWAP | |
217 | /* linux/mm/page_io.c */ | |
218 | extern int swap_readpage(struct file *, struct page *); | |
219 | extern int swap_writepage(struct page *page, struct writeback_control *wbc); | |
6712ecf8 | 220 | extern void end_swap_bio_read(struct bio *bio, int err); |
1da177e4 LT |
221 | |
222 | /* linux/mm/swap_state.c */ | |
223 | extern struct address_space swapper_space; | |
224 | #define total_swapcache_pages swapper_space.nrpages | |
225 | extern void show_swap_cache_info(void); | |
1480a540 | 226 | extern int add_to_swap(struct page *, gfp_t); |
73b1262f | 227 | extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t); |
1da177e4 LT |
228 | extern void __delete_from_swap_cache(struct page *); |
229 | extern void delete_from_swap_cache(struct page *); | |
1da177e4 LT |
230 | extern void free_page_and_swap_cache(struct page *); |
231 | extern void free_pages_and_swap_cache(struct page **, int); | |
46017e95 | 232 | extern struct page *lookup_swap_cache(swp_entry_t); |
02098fea | 233 | extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, |
46017e95 | 234 | struct vm_area_struct *vma, unsigned long addr); |
02098fea | 235 | extern struct page *swapin_readahead(swp_entry_t, gfp_t, |
46017e95 HD |
236 | struct vm_area_struct *vma, unsigned long addr); |
237 | ||
1da177e4 LT |
238 | /* linux/mm/swapfile.c */ |
239 | extern long total_swap_pages; | |
240 | extern unsigned int nr_swapfiles; | |
1da177e4 LT |
241 | extern void si_swapinfo(struct sysinfo *); |
242 | extern swp_entry_t get_swap_page(void); | |
f577eb30 | 243 | extern swp_entry_t get_swap_page_of_type(int); |
1da177e4 LT |
244 | extern int swap_duplicate(swp_entry_t); |
245 | extern int valid_swaphandles(swp_entry_t, unsigned long *); | |
246 | extern void swap_free(swp_entry_t); | |
247 | extern void free_swap_and_cache(swp_entry_t); | |
7bf23687 | 248 | extern int swap_type_of(dev_t, sector_t, struct block_device **); |
f577eb30 | 249 | extern unsigned int count_swap_pages(int, int); |
1da177e4 | 250 | extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t); |
3aef83e0 | 251 | extern sector_t swapdev_block(int, pgoff_t); |
1da177e4 LT |
252 | extern struct swap_info_struct *get_swap_info_struct(unsigned); |
253 | extern int can_share_swap_page(struct page *); | |
254 | extern int remove_exclusive_swap_page(struct page *); | |
255 | struct backing_dev_info; | |
256 | ||
5d337b91 | 257 | extern spinlock_t swap_lock; |
1da177e4 LT |
258 | |
259 | /* linux/mm/thrash.c */ | |
260 | extern struct mm_struct * swap_token_mm; | |
1da177e4 LT |
261 | extern void grab_swap_token(void); |
262 | extern void __put_swap_token(struct mm_struct *); | |
263 | ||
264 | static inline int has_swap_token(struct mm_struct *mm) | |
265 | { | |
266 | return (mm == swap_token_mm); | |
267 | } | |
268 | ||
269 | static inline void put_swap_token(struct mm_struct *mm) | |
270 | { | |
271 | if (has_swap_token(mm)) | |
272 | __put_swap_token(mm); | |
273 | } | |
274 | ||
f7b7fd8f RR |
275 | static inline void disable_swap_token(void) |
276 | { | |
277 | put_swap_token(swap_token_mm); | |
278 | } | |
279 | ||
1da177e4 LT |
280 | #else /* CONFIG_SWAP */ |
281 | ||
282 | #define total_swap_pages 0 | |
283 | #define total_swapcache_pages 0UL | |
284 | ||
285 | #define si_swapinfo(val) \ | |
286 | do { (val)->freeswap = (val)->totalswap = 0; } while (0) | |
9ae5b3c7 OH |
287 | /* only sparc can not include linux/pagemap.h in this file |
288 | * so leave page_cache_release and release_pages undeclared... */ | |
1da177e4 LT |
289 | #define free_page_and_swap_cache(page) \ |
290 | page_cache_release(page) | |
291 | #define free_pages_and_swap_cache(pages, nr) \ | |
292 | release_pages((pages), (nr), 0); | |
293 | ||
bd96b9eb CK |
294 | static inline void show_swap_cache_info(void) |
295 | { | |
296 | } | |
297 | ||
298 | static inline void free_swap_and_cache(swp_entry_t swp) | |
299 | { | |
300 | } | |
301 | ||
302 | static inline int swap_duplicate(swp_entry_t swp) | |
303 | { | |
304 | return 0; | |
305 | } | |
306 | ||
307 | static inline void swap_free(swp_entry_t swp) | |
308 | { | |
309 | } | |
310 | ||
02098fea | 311 | static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, |
bd96b9eb CK |
312 | struct vm_area_struct *vma, unsigned long addr) |
313 | { | |
314 | return NULL; | |
315 | } | |
316 | ||
317 | static inline struct page *lookup_swap_cache(swp_entry_t swp) | |
318 | { | |
319 | return NULL; | |
320 | } | |
321 | ||
e6333fd4 | 322 | #define can_share_swap_page(p) (page_mapcount(p) == 1) |
bd96b9eb | 323 | |
73b1262f HD |
324 | static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, |
325 | gfp_t gfp_mask) | |
bd96b9eb | 326 | { |
73b1262f | 327 | return -1; |
bd96b9eb CK |
328 | } |
329 | ||
330 | static inline void __delete_from_swap_cache(struct page *page) | |
331 | { | |
332 | } | |
333 | ||
334 | static inline void delete_from_swap_cache(struct page *page) | |
335 | { | |
336 | } | |
337 | ||
1da177e4 LT |
338 | #define swap_token_default_timeout 0 |
339 | ||
340 | static inline int remove_exclusive_swap_page(struct page *p) | |
341 | { | |
342 | return 0; | |
343 | } | |
344 | ||
345 | static inline swp_entry_t get_swap_page(void) | |
346 | { | |
347 | swp_entry_t entry; | |
348 | entry.val = 0; | |
349 | return entry; | |
350 | } | |
351 | ||
352 | /* linux/mm/thrash.c */ | |
353 | #define put_swap_token(x) do { } while(0) | |
354 | #define grab_swap_token() do { } while(0) | |
355 | #define has_swap_token(x) 0 | |
f7b7fd8f | 356 | #define disable_swap_token() do { } while(0) |
1da177e4 LT |
357 | |
358 | #endif /* CONFIG_SWAP */ | |
359 | #endif /* __KERNEL__*/ | |
360 | #endif /* _LINUX_SWAP_H */ |