1 #ifndef _LINUX_SWAP_H
2 #define _LINUX_SWAP_H
3
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>
10 #include <linux/node.h>
11
12 #include <asm/atomic.h>
13 #include <asm/page.h>
14
15 struct notifier_block;
16
17 struct bio;
18
19 #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
20 #define SWAP_FLAG_PRIO_MASK 0x7fff
21 #define SWAP_FLAG_PRIO_SHIFT 0
22
current_is_kswapd(void)23 static inline int current_is_kswapd(void)
24 {
25 return current->flags & PF_KSWAPD;
26 }
27
28 /*
29 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
30 * be swapped to. The swap type and the offset into that swap type are
31 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits
32 * for the type means that the maximum number of swapcache pages is 27 bits
33 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
34 * the type/offset into the pte as 5/27 as well.
35 */
36 #define MAX_SWAPFILES_SHIFT 5
37 #ifndef CONFIG_MIGRATION
38 #define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
39 #else
40 /* Use last two entries for page migration swap entries */
41 #define MAX_SWAPFILES ((1 << MAX_SWAPFILES_SHIFT)-2)
42 #define SWP_MIGRATION_READ MAX_SWAPFILES
43 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + 1)
44 #endif
45
46 /*
47 * Magic header for a swap area. The first part of the union is
48 * what the swap magic looks like for the old (limited to 128MB)
49 * swap area format, the second part of the union adds - in the
50 * old reserved area - some extra information. Note that the first
51 * kilobyte is reserved for boot loader or disk label stuff...
52 *
53 * Having the magic at the end of the PAGE_SIZE makes detecting swap
54 * areas somewhat tricky on machines that support multiple page sizes.
55 * For 2.5 we'll probably want to move the magic to just beyond the
56 * bootbits...
57 */
58 union swap_header {
59 struct {
60 char reserved[PAGE_SIZE - 10];
61 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
62 } magic;
63 struct {
64 char bootbits[1024]; /* Space for disklabel etc. */
65 __u32 version;
66 __u32 last_page;
67 __u32 nr_badpages;
68 unsigned char sws_uuid[16];
69 unsigned char sws_volume[16];
70 __u32 padding[117];
71 __u32 badpages[1];
72 } info;
73 };
74
75 /* A swap entry has to fit into a "unsigned long", as
76 * the entry is hidden in the "index" field of the
77 * swapper address space.
78 */
79 typedef struct {
80 unsigned long val;
81 } swp_entry_t;
82
83 /*
84 * current->reclaim_state points to one of these when a task is running
85 * memory reclaim
86 */
87 struct reclaim_state {
88 unsigned long reclaimed_slab;
89 };
90
91 #ifdef __KERNEL__
92
93 struct address_space;
94 struct sysinfo;
95 struct writeback_control;
96 struct zone;
97
98 /*
99 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
100 * disk blocks. A list of swap extents maps the entire swapfile. (Where the
101 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
102 * from setup, they're handled identically.
103 *
104 * We always assume that blocks are of size PAGE_SIZE.
105 */
106 struct swap_extent {
107 struct list_head list;
108 pgoff_t start_page;
109 pgoff_t nr_pages;
110 sector_t start_block;
111 };
112
113 /*
114 * Max bad pages in the new format..
115 */
116 #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
117 #define MAX_SWAP_BADPAGES \
118 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
119
120 enum {
121 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
122 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
123 SWP_DISCARDABLE = (1 << 2), /* blkdev supports discard */
124 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
125 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
126 /* add others here before... */
127 SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
128 };
129
130 #define SWAP_CLUSTER_MAX 32
131
132 #define SWAP_MAP_MAX 0x7fff
133 #define SWAP_MAP_BAD 0x8000
134
135 /*
136 * The in-memory structure used to track swap areas.
137 */
138 struct swap_info_struct {
139 unsigned long flags;
140 int prio; /* swap priority */
141 int next; /* next entry on swap list */
142 struct file *swap_file;
143 struct block_device *bdev;
144 struct list_head extent_list;
145 struct swap_extent *curr_swap_extent;
146 unsigned short *swap_map;
147 unsigned int lowest_bit;
148 unsigned int highest_bit;
149 unsigned int lowest_alloc; /* while preparing discard cluster */
150 unsigned int highest_alloc; /* while preparing discard cluster */
151 unsigned int cluster_next;
152 unsigned int cluster_nr;
153 unsigned int pages;
154 unsigned int max;
155 unsigned int inuse_pages;
156 unsigned int old_block_size;
157 };
158
159 struct swap_list_t {
160 int head; /* head of priority-ordered swapfile list */
161 int next; /* swapfile to be used next */
162 };
163
164 /* Swap 50% full? Release swapcache more aggressively.. */
165 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
166
167 /* linux/mm/page_alloc.c */
168 extern unsigned long totalram_pages;
169 extern unsigned long totalreserve_pages;
170 extern unsigned int nr_free_buffer_pages(void);
171 extern unsigned int nr_free_pagecache_pages(void);
172
173 /* Definition of global_page_state not available yet */
174 #define nr_free_pages() global_page_state(NR_FREE_PAGES)
175
176
177 /* linux/mm/swap.c */
178 extern void __lru_cache_add(struct page *, enum lru_list lru);
179 extern void lru_cache_add_lru(struct page *, enum lru_list lru);
180 extern void activate_page(struct page *);
181 extern void mark_page_accessed(struct page *);
182 extern void lru_add_drain(void);
183 extern int lru_add_drain_all(void);
184 extern void rotate_reclaimable_page(struct page *page);
185 extern void swap_setup(void);
186
187 extern void add_page_to_unevictable_list(struct page *page);
188
189 /**
190 * lru_cache_add: add a page to the page lists
191 * @page: the page to add
192 */
lru_cache_add_anon(struct page * page)193 static inline void lru_cache_add_anon(struct page *page)
194 {
195 __lru_cache_add(page, LRU_INACTIVE_ANON);
196 }
197
lru_cache_add_active_anon(struct page * page)198 static inline void lru_cache_add_active_anon(struct page *page)
199 {
200 __lru_cache_add(page, LRU_ACTIVE_ANON);
201 }
202
lru_cache_add_file(struct page * page)203 static inline void lru_cache_add_file(struct page *page)
204 {
205 __lru_cache_add(page, LRU_INACTIVE_FILE);
206 }
207
lru_cache_add_active_file(struct page * page)208 static inline void lru_cache_add_active_file(struct page *page)
209 {
210 __lru_cache_add(page, LRU_ACTIVE_FILE);
211 }
212
213 /* linux/mm/vmscan.c */
214 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
215 gfp_t gfp_mask);
216 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
217 gfp_t gfp_mask, bool noswap,
218 unsigned int swappiness);
219 extern int __isolate_lru_page(struct page *page, int mode, int file);
220 extern unsigned long shrink_all_memory(unsigned long nr_pages);
221 extern int vm_swappiness;
222 extern int remove_mapping(struct address_space *mapping, struct page *page);
223 extern long vm_total_pages;
224
225 #ifdef CONFIG_NUMA
226 extern int zone_reclaim_mode;
227 extern int sysctl_min_unmapped_ratio;
228 extern int sysctl_min_slab_ratio;
229 extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
230 #else
231 #define zone_reclaim_mode 0
zone_reclaim(struct zone * z,gfp_t mask,unsigned int order)232 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
233 {
234 return 0;
235 }
236 #endif
237
238 #ifdef CONFIG_UNEVICTABLE_LRU
239 extern int page_evictable(struct page *page, struct vm_area_struct *vma);
240 extern void scan_mapping_unevictable_pages(struct address_space *);
241
242 extern unsigned long scan_unevictable_pages;
243 extern int scan_unevictable_handler(struct ctl_table *, int, struct file *,
244 void __user *, size_t *, loff_t *);
245 extern int scan_unevictable_register_node(struct node *node);
246 extern void scan_unevictable_unregister_node(struct node *node);
247 #else
page_evictable(struct page * page,struct vm_area_struct * vma)248 static inline int page_evictable(struct page *page,
249 struct vm_area_struct *vma)
250 {
251 return 1;
252 }
253
scan_mapping_unevictable_pages(struct address_space * mapping)254 static inline void scan_mapping_unevictable_pages(struct address_space *mapping)
255 {
256 }
257
scan_unevictable_register_node(struct node * node)258 static inline int scan_unevictable_register_node(struct node *node)
259 {
260 return 0;
261 }
262
scan_unevictable_unregister_node(struct node * node)263 static inline void scan_unevictable_unregister_node(struct node *node) { }
264 #endif
265
266 extern int kswapd_run(int nid);
267
268 #ifdef CONFIG_MMU
269 /* linux/mm/shmem.c */
270 extern int shmem_unuse(swp_entry_t entry, struct page *page);
271 #endif /* CONFIG_MMU */
272
273 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);
274
275 #ifdef CONFIG_SWAP
276 /* linux/mm/page_io.c */
277 extern int swap_readpage(struct file *, struct page *);
278 extern int swap_writepage(struct page *page, struct writeback_control *wbc);
279 extern void end_swap_bio_read(struct bio *bio, int err);
280
281 /* linux/mm/swap_state.c */
282 extern struct address_space swapper_space;
283 #define total_swapcache_pages swapper_space.nrpages
284 extern void show_swap_cache_info(void);
285 extern int add_to_swap(struct page *);
286 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
287 extern void __delete_from_swap_cache(struct page *);
288 extern void delete_from_swap_cache(struct page *);
289 extern void free_page_and_swap_cache(struct page *);
290 extern void free_pages_and_swap_cache(struct page **, int);
291 extern struct page *lookup_swap_cache(swp_entry_t);
292 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
293 struct vm_area_struct *vma, unsigned long addr);
294 extern struct page *swapin_readahead(swp_entry_t, gfp_t,
295 struct vm_area_struct *vma, unsigned long addr);
296
297 /* linux/mm/swapfile.c */
298 extern long nr_swap_pages;
299 extern long total_swap_pages;
300 extern void si_swapinfo(struct sysinfo *);
301 extern swp_entry_t get_swap_page(void);
302 extern swp_entry_t get_swap_page_of_type(int);
303 extern int swap_duplicate(swp_entry_t);
304 extern int valid_swaphandles(swp_entry_t, unsigned long *);
305 extern void swap_free(swp_entry_t);
306 extern int free_swap_and_cache(swp_entry_t);
307 extern int swap_type_of(dev_t, sector_t, struct block_device **);
308 extern unsigned int count_swap_pages(int, int);
309 extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
310 extern sector_t swapdev_block(int, pgoff_t);
311 extern struct swap_info_struct *get_swap_info_struct(unsigned);
312 extern int reuse_swap_page(struct page *);
313 extern int try_to_free_swap(struct page *);
314 struct backing_dev_info;
315
316 /* linux/mm/thrash.c */
317 extern struct mm_struct * swap_token_mm;
318 extern void grab_swap_token(void);
319 extern void __put_swap_token(struct mm_struct *);
320
has_swap_token(struct mm_struct * mm)321 static inline int has_swap_token(struct mm_struct *mm)
322 {
323 return (mm == swap_token_mm);
324 }
325
put_swap_token(struct mm_struct * mm)326 static inline void put_swap_token(struct mm_struct *mm)
327 {
328 if (has_swap_token(mm))
329 __put_swap_token(mm);
330 }
331
disable_swap_token(void)332 static inline void disable_swap_token(void)
333 {
334 put_swap_token(swap_token_mm);
335 }
336
337 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
338 extern void mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent);
339 #else
340 static inline void
mem_cgroup_uncharge_swapcache(struct page * page,swp_entry_t ent)341 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
342 {
343 }
344 #endif
345 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
346 extern void mem_cgroup_uncharge_swap(swp_entry_t ent);
347 #else
mem_cgroup_uncharge_swap(swp_entry_t ent)348 static inline void mem_cgroup_uncharge_swap(swp_entry_t ent)
349 {
350 }
351 #endif
352
353 #else /* CONFIG_SWAP */
354
355 #define nr_swap_pages 0L
356 #define total_swap_pages 0L
357 #define total_swapcache_pages 0UL
358
359 #define si_swapinfo(val) \
360 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
361 /* only sparc can not include linux/pagemap.h in this file
362 * so leave page_cache_release and release_pages undeclared... */
363 #define free_page_and_swap_cache(page) \
364 page_cache_release(page)
365 #define free_pages_and_swap_cache(pages, nr) \
366 release_pages((pages), (nr), 0);
367
show_swap_cache_info(void)368 static inline void show_swap_cache_info(void)
369 {
370 }
371
372 #define free_swap_and_cache(swp) is_migration_entry(swp)
373 #define swap_duplicate(swp) is_migration_entry(swp)
374
swap_free(swp_entry_t swp)375 static inline void swap_free(swp_entry_t swp)
376 {
377 }
378
swapin_readahead(swp_entry_t swp,gfp_t gfp_mask,struct vm_area_struct * vma,unsigned long addr)379 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
380 struct vm_area_struct *vma, unsigned long addr)
381 {
382 return NULL;
383 }
384
lookup_swap_cache(swp_entry_t swp)385 static inline struct page *lookup_swap_cache(swp_entry_t swp)
386 {
387 return NULL;
388 }
389
add_to_swap(struct page * page)390 static inline int add_to_swap(struct page *page)
391 {
392 return 0;
393 }
394
add_to_swap_cache(struct page * page,swp_entry_t entry,gfp_t gfp_mask)395 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
396 gfp_t gfp_mask)
397 {
398 return -1;
399 }
400
__delete_from_swap_cache(struct page * page)401 static inline void __delete_from_swap_cache(struct page *page)
402 {
403 }
404
delete_from_swap_cache(struct page * page)405 static inline void delete_from_swap_cache(struct page *page)
406 {
407 }
408
409 #define reuse_swap_page(page) (page_mapcount(page) == 1)
410
try_to_free_swap(struct page * page)411 static inline int try_to_free_swap(struct page *page)
412 {
413 return 0;
414 }
415
get_swap_page(void)416 static inline swp_entry_t get_swap_page(void)
417 {
418 swp_entry_t entry;
419 entry.val = 0;
420 return entry;
421 }
422
423 /* linux/mm/thrash.c */
424 #define put_swap_token(x) do { } while(0)
425 #define grab_swap_token() do { } while(0)
426 #define has_swap_token(x) 0
427 #define disable_swap_token() do { } while(0)
428
mem_cgroup_cache_charge_swapin(struct page * page,struct mm_struct * mm,gfp_t mask,bool locked)429 static inline int mem_cgroup_cache_charge_swapin(struct page *page,
430 struct mm_struct *mm, gfp_t mask, bool locked)
431 {
432 return 0;
433 }
434
435 #endif /* CONFIG_SWAP */
436 #endif /* __KERNEL__*/
437 #endif /* _LINUX_SWAP_H */
438