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#include <linux/fs.h>
12#include <linux/atomic.h>
13#include <linux/page-flags.h>
14#include <asm/page.h>
15
16struct notifier_block;
17
18struct bio;
19
20#define SWAP_FLAG_PREFER 0x8000
21#define SWAP_FLAG_PRIO_MASK 0x7fff
22#define SWAP_FLAG_PRIO_SHIFT 0
23#define SWAP_FLAG_DISCARD 0x10000
24#define SWAP_FLAG_DISCARD_ONCE 0x20000
25#define SWAP_FLAG_DISCARD_PAGES 0x40000
26
27#define SWAP_FLAGS_VALID (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \
28 SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \
29 SWAP_FLAG_DISCARD_PAGES)
30
31static inline int current_is_kswapd(void)
32{
33 return current->flags & PF_KSWAPD;
34}
35
36
37
38
39
40
41
42
43
44#define MAX_SWAPFILES_SHIFT 5
45
46
47
48
49
50
51
52
53
54
55#ifdef CONFIG_MIGRATION
56#define SWP_MIGRATION_NUM 2
57#define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
58#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
59#else
60#define SWP_MIGRATION_NUM 0
61#endif
62
63
64
65
66#ifdef CONFIG_MEMORY_FAILURE
67#define SWP_HWPOISON_NUM 1
68#define SWP_HWPOISON MAX_SWAPFILES
69#else
70#define SWP_HWPOISON_NUM 0
71#endif
72
73#define MAX_SWAPFILES \
74 ((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)
75
76
77
78
79
80
81
82
83
84
85
86
87
88union swap_header {
89 struct {
90 char reserved[PAGE_SIZE - 10];
91 char magic[10];
92 } magic;
93 struct {
94 char bootbits[1024];
95 __u32 version;
96 __u32 last_page;
97 __u32 nr_badpages;
98 unsigned char sws_uuid[16];
99 unsigned char sws_volume[16];
100 __u32 padding[117];
101 __u32 badpages[1];
102 } info;
103};
104
105
106
107
108
109typedef struct {
110 unsigned long val;
111} swp_entry_t;
112
113
114
115
116
117struct reclaim_state {
118 unsigned long reclaimed_slab;
119};
120
121#ifdef __KERNEL__
122
123struct address_space;
124struct sysinfo;
125struct writeback_control;
126struct zone;
127
128
129
130
131
132
133
134
135
136struct swap_extent {
137 struct list_head list;
138 pgoff_t start_page;
139 pgoff_t nr_pages;
140 sector_t start_block;
141};
142
143
144
145
146#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
147#define MAX_SWAP_BADPAGES \
148 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
149
150enum {
151 SWP_USED = (1 << 0),
152 SWP_WRITEOK = (1 << 1),
153 SWP_DISCARDABLE = (1 << 2),
154 SWP_DISCARDING = (1 << 3),
155 SWP_SOLIDSTATE = (1 << 4),
156 SWP_CONTINUED = (1 << 5),
157 SWP_BLKDEV = (1 << 6),
158 SWP_FILE = (1 << 7),
159 SWP_AREA_DISCARD = (1 << 8),
160 SWP_PAGE_DISCARD = (1 << 9),
161
162 SWP_SCANNING = (1 << 10),
163};
164
165#define SWAP_CLUSTER_MAX 32UL
166#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
167
168
169
170
171
172
173
174
175#define KSWAPD_ZONE_BALANCE_GAP_RATIO 100
176
177#define SWAP_MAP_MAX 0x3e
178#define SWAP_MAP_BAD 0x3f
179#define SWAP_HAS_CACHE 0x40
180#define SWAP_CONT_MAX 0x7f
181#define COUNT_CONTINUED 0x80
182#define SWAP_MAP_SHMEM 0xbf
183
184
185
186
187struct swap_info_struct {
188 unsigned long flags;
189 signed short prio;
190 signed char type;
191 signed char next;
192 unsigned int max;
193 unsigned char *swap_map;
194 unsigned int lowest_bit;
195 unsigned int highest_bit;
196 unsigned int pages;
197 unsigned int inuse_pages;
198 unsigned int cluster_next;
199 unsigned int cluster_nr;
200 unsigned int lowest_alloc;
201 unsigned int highest_alloc;
202 struct swap_extent *curr_swap_extent;
203 struct swap_extent first_swap_extent;
204 struct block_device *bdev;
205 struct file *swap_file;
206 unsigned int old_block_size;
207#ifdef CONFIG_FRONTSWAP
208 unsigned long *frontswap_map;
209 atomic_t frontswap_pages;
210#endif
211 spinlock_t lock;
212
213
214
215
216
217
218
219
220
221
222
223};
224
225struct swap_list_t {
226 int head;
227 int next;
228};
229
230
231extern unsigned long totalram_pages;
232extern unsigned long totalreserve_pages;
233extern unsigned long dirty_balance_reserve;
234extern unsigned long nr_free_buffer_pages(void);
235extern unsigned long nr_free_pagecache_pages(void);
236
237
238#define nr_free_pages() global_page_state(NR_FREE_PAGES)
239
240
241
242extern void __lru_cache_add(struct page *);
243extern void lru_cache_add(struct page *);
244extern void lru_add_page_tail(struct page *page, struct page *page_tail,
245 struct lruvec *lruvec, struct list_head *head);
246extern void activate_page(struct page *);
247extern void mark_page_accessed(struct page *);
248extern void lru_add_drain(void);
249extern void lru_add_drain_cpu(int cpu);
250extern int lru_add_drain_all(void);
251extern void rotate_reclaimable_page(struct page *page);
252extern void deactivate_page(struct page *page);
253extern void swap_setup(void);
254
255extern void add_page_to_unevictable_list(struct page *page);
256
257
258
259
260
261static inline void lru_cache_add_anon(struct page *page)
262{
263 ClearPageActive(page);
264 __lru_cache_add(page);
265}
266
267static inline void lru_cache_add_file(struct page *page)
268{
269 ClearPageActive(page);
270 __lru_cache_add(page);
271}
272
273
274extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
275 gfp_t gfp_mask, nodemask_t *mask);
276extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
277extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
278 gfp_t gfp_mask, bool noswap);
279extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
280 gfp_t gfp_mask, bool noswap,
281 struct zone *zone,
282 unsigned long *nr_scanned);
283extern unsigned long shrink_all_memory(unsigned long nr_pages);
284extern int vm_swappiness;
285extern int remove_mapping(struct address_space *mapping, struct page *page);
286extern unsigned long vm_total_pages;
287
288#ifdef CONFIG_NUMA
289extern int zone_reclaim_mode;
290extern int sysctl_min_unmapped_ratio;
291extern int sysctl_min_slab_ratio;
292extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
293#else
294#define zone_reclaim_mode 0
295static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
296{
297 return 0;
298}
299#endif
300
301extern int page_evictable(struct page *page);
302extern void check_move_unevictable_pages(struct page **, int nr_pages);
303
304extern unsigned long scan_unevictable_pages;
305extern int scan_unevictable_handler(struct ctl_table *, int,
306 void __user *, size_t *, loff_t *);
307#ifdef CONFIG_NUMA
308extern int scan_unevictable_register_node(struct node *node);
309extern void scan_unevictable_unregister_node(struct node *node);
310#else
311static inline int scan_unevictable_register_node(struct node *node)
312{
313 return 0;
314}
315static inline void scan_unevictable_unregister_node(struct node *node)
316{
317}
318#endif
319
320extern int kswapd_run(int nid);
321extern void kswapd_stop(int nid);
322#ifdef CONFIG_MEMCG
323extern int mem_cgroup_swappiness(struct mem_cgroup *mem);
324#else
325static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
326{
327 return vm_swappiness;
328}
329#endif
330#ifdef CONFIG_MEMCG_SWAP
331extern void mem_cgroup_uncharge_swap(swp_entry_t ent);
332#else
333static inline void mem_cgroup_uncharge_swap(swp_entry_t ent)
334{
335}
336#endif
337#ifdef CONFIG_SWAP
338
339extern int swap_readpage(struct page *);
340extern int swap_writepage(struct page *page, struct writeback_control *wbc);
341extern void end_swap_bio_write(struct bio *bio, int err);
342extern int __swap_writepage(struct page *page, struct writeback_control *wbc,
343 void (*end_write_func)(struct bio *, int));
344extern int swap_set_page_dirty(struct page *page);
345extern void end_swap_bio_read(struct bio *bio, int err);
346
347int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
348 unsigned long nr_pages, sector_t start_block);
349int generic_swapfile_activate(struct swap_info_struct *, struct file *,
350 sector_t *);
351
352
353extern struct address_space swapper_spaces[];
354#define swap_address_space(entry) (&swapper_spaces[swp_type(entry)])
355extern unsigned long total_swapcache_pages(void);
356extern void show_swap_cache_info(void);
357extern int add_to_swap(struct page *, struct list_head *list);
358extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
359extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
360extern void __delete_from_swap_cache(struct page *);
361extern void delete_from_swap_cache(struct page *);
362extern void free_page_and_swap_cache(struct page *);
363extern void free_pages_and_swap_cache(struct page **, int);
364extern struct page *lookup_swap_cache(swp_entry_t);
365extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
366 struct vm_area_struct *vma, unsigned long addr);
367extern struct page *swapin_readahead(swp_entry_t, gfp_t,
368 struct vm_area_struct *vma, unsigned long addr);
369
370
371extern atomic_long_t nr_swap_pages;
372extern long total_swap_pages;
373
374
375static inline bool vm_swap_full(void)
376{
377 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
378}
379
380static inline long get_nr_swap_pages(void)
381{
382 return atomic_long_read(&nr_swap_pages);
383}
384
385extern void si_swapinfo(struct sysinfo *);
386extern swp_entry_t get_swap_page(void);
387extern swp_entry_t get_swap_page_of_type(int);
388extern int add_swap_count_continuation(swp_entry_t, gfp_t);
389extern void swap_shmem_alloc(swp_entry_t);
390extern int swap_duplicate(swp_entry_t);
391extern int swapcache_prepare(swp_entry_t);
392extern void swap_free(swp_entry_t);
393extern void swapcache_free(swp_entry_t, struct page *page);
394extern int free_swap_and_cache(swp_entry_t);
395extern int swap_type_of(dev_t, sector_t, struct block_device **);
396extern unsigned int count_swap_pages(int, int);
397extern sector_t map_swap_page(struct page *, struct block_device **);
398extern sector_t swapdev_block(int, pgoff_t);
399extern int page_swapcount(struct page *);
400extern struct swap_info_struct *page_swap_info(struct page *);
401extern int reuse_swap_page(struct page *);
402extern int try_to_free_swap(struct page *);
403struct backing_dev_info;
404
405#ifdef CONFIG_MEMCG
406extern void
407mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout);
408#else
409static inline void
410mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
411{
412}
413#endif
414
415#else
416
417#define get_nr_swap_pages() 0L
418#define total_swap_pages 0L
419#define total_swapcache_pages() 0UL
420#define vm_swap_full() 0
421
422#define si_swapinfo(val) \
423 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
424
425
426#define free_page_and_swap_cache(page) \
427 page_cache_release(page)
428#define free_pages_and_swap_cache(pages, nr) \
429 release_pages((pages), (nr), 0);
430
431static inline void show_swap_cache_info(void)
432{
433}
434
435#define free_swap_and_cache(swp) is_migration_entry(swp)
436#define swapcache_prepare(swp) is_migration_entry(swp)
437
438static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
439{
440 return 0;
441}
442
443static inline void swap_shmem_alloc(swp_entry_t swp)
444{
445}
446
447static inline int swap_duplicate(swp_entry_t swp)
448{
449 return 0;
450}
451
452static inline void swap_free(swp_entry_t swp)
453{
454}
455
456static inline void swapcache_free(swp_entry_t swp, struct page *page)
457{
458}
459
460static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
461 struct vm_area_struct *vma, unsigned long addr)
462{
463 return NULL;
464}
465
466static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
467{
468 return 0;
469}
470
471static inline struct page *lookup_swap_cache(swp_entry_t swp)
472{
473 return NULL;
474}
475
476static inline int add_to_swap(struct page *page, struct list_head *list)
477{
478 return 0;
479}
480
481static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
482 gfp_t gfp_mask)
483{
484 return -1;
485}
486
487static inline void __delete_from_swap_cache(struct page *page)
488{
489}
490
491static inline void delete_from_swap_cache(struct page *page)
492{
493}
494
495static inline int page_swapcount(struct page *page)
496{
497 return 0;
498}
499
500#define reuse_swap_page(page) (page_mapcount(page) == 1)
501
502static inline int try_to_free_swap(struct page *page)
503{
504 return 0;
505}
506
507static inline swp_entry_t get_swap_page(void)
508{
509 swp_entry_t entry;
510 entry.val = 0;
511 return entry;
512}
513
514static inline void
515mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
516{
517}
518
519#endif
520#endif
521#endif
522