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