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
109struct reclaim_state {
110 unsigned long reclaimed_slab;
111};
112
113#ifdef __KERNEL__
114
115struct address_space;
116struct sysinfo;
117struct writeback_control;
118struct zone;
119
120
121
122
123
124
125
126
127
128struct swap_extent {
129 struct list_head list;
130 pgoff_t start_page;
131 pgoff_t nr_pages;
132 sector_t start_block;
133};
134
135
136
137
138#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
139#define MAX_SWAP_BADPAGES \
140 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
141
142enum {
143 SWP_USED = (1 << 0),
144 SWP_WRITEOK = (1 << 1),
145 SWP_DISCARDABLE = (1 << 2),
146 SWP_DISCARDING = (1 << 3),
147 SWP_SOLIDSTATE = (1 << 4),
148 SWP_CONTINUED = (1 << 5),
149 SWP_BLKDEV = (1 << 6),
150 SWP_FILE = (1 << 7),
151 SWP_AREA_DISCARD = (1 << 8),
152 SWP_PAGE_DISCARD = (1 << 9),
153
154 SWP_SCANNING = (1 << 10),
155};
156
157#define SWAP_CLUSTER_MAX 32UL
158#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
159
160
161
162
163
164
165
166
167#define KSWAPD_ZONE_BALANCE_GAP_RATIO 100
168
169#define SWAP_MAP_MAX 0x3e
170#define SWAP_MAP_BAD 0x3f
171#define SWAP_HAS_CACHE 0x40
172#define SWAP_CONT_MAX 0x7f
173#define COUNT_CONTINUED 0x80
174#define SWAP_MAP_SHMEM 0xbf
175
176
177
178
179
180
181
182
183
184
185
186struct swap_cluster_info {
187 unsigned int data:24;
188 unsigned int flags:8;
189};
190#define CLUSTER_FLAG_FREE 1
191#define CLUSTER_FLAG_NEXT_NULL 2
192
193
194
195
196
197
198struct percpu_cluster {
199 struct swap_cluster_info index;
200 unsigned int next;
201};
202
203
204
205
206struct swap_info_struct {
207 unsigned long flags;
208 signed short prio;
209 struct plist_node list;
210 struct plist_node avail_list;
211 signed char type;
212 unsigned int max;
213 unsigned char *swap_map;
214 struct swap_cluster_info *cluster_info;
215 struct swap_cluster_info free_cluster_head;
216 struct swap_cluster_info free_cluster_tail;
217 unsigned int lowest_bit;
218 unsigned int highest_bit;
219 unsigned int pages;
220 unsigned int inuse_pages;
221 unsigned int cluster_next;
222 unsigned int cluster_nr;
223 struct percpu_cluster __percpu *percpu_cluster;
224 struct swap_extent *curr_swap_extent;
225 struct swap_extent first_swap_extent;
226 struct block_device *bdev;
227 struct file *swap_file;
228 unsigned int old_block_size;
229#ifdef CONFIG_FRONTSWAP
230 unsigned long *frontswap_map;
231 atomic_t frontswap_pages;
232#endif
233 spinlock_t lock;
234
235
236
237
238
239
240
241
242
243
244
245
246 struct work_struct discard_work;
247 struct swap_cluster_info discard_cluster_head;
248 struct swap_cluster_info discard_cluster_tail;
249};
250
251
252void *workingset_eviction(struct address_space *mapping, struct page *page);
253bool workingset_refault(void *shadow);
254void workingset_activation(struct page *page);
255extern struct list_lru workingset_shadow_nodes;
256
257static inline unsigned int workingset_node_pages(struct radix_tree_node *node)
258{
259 return node->count & RADIX_TREE_COUNT_MASK;
260}
261
262static inline void workingset_node_pages_inc(struct radix_tree_node *node)
263{
264 node->count++;
265}
266
267static inline void workingset_node_pages_dec(struct radix_tree_node *node)
268{
269 node->count--;
270}
271
272static inline unsigned int workingset_node_shadows(struct radix_tree_node *node)
273{
274 return node->count >> RADIX_TREE_COUNT_SHIFT;
275}
276
277static inline void workingset_node_shadows_inc(struct radix_tree_node *node)
278{
279 node->count += 1U << RADIX_TREE_COUNT_SHIFT;
280}
281
282static inline void workingset_node_shadows_dec(struct radix_tree_node *node)
283{
284 node->count -= 1U << RADIX_TREE_COUNT_SHIFT;
285}
286
287
288extern unsigned long totalram_pages;
289extern unsigned long totalreserve_pages;
290extern unsigned long nr_free_buffer_pages(void);
291extern unsigned long nr_free_pagecache_pages(void);
292
293
294#define nr_free_pages() global_page_state(NR_FREE_PAGES)
295
296
297
298extern void lru_cache_add(struct page *);
299extern void lru_cache_add_anon(struct page *page);
300extern void lru_cache_add_file(struct page *page);
301extern void lru_add_page_tail(struct page *page, struct page *page_tail,
302 struct lruvec *lruvec, struct list_head *head);
303extern void activate_page(struct page *);
304extern void mark_page_accessed(struct page *);
305extern void lru_add_drain(void);
306extern void lru_add_drain_cpu(int cpu);
307extern void lru_add_drain_all(void);
308extern void rotate_reclaimable_page(struct page *page);
309extern void deactivate_file_page(struct page *page);
310extern void deactivate_page(struct page *page);
311extern void swap_setup(void);
312
313extern void add_page_to_unevictable_list(struct page *page);
314
315extern void lru_cache_add_active_or_unevictable(struct page *page,
316 struct vm_area_struct *vma);
317
318
319extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
320 gfp_t gfp_mask, nodemask_t *mask);
321extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
322extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
323 unsigned long nr_pages,
324 gfp_t gfp_mask,
325 bool may_swap);
326extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
327 gfp_t gfp_mask, bool noswap,
328 struct zone *zone,
329 unsigned long *nr_scanned);
330extern unsigned long shrink_all_memory(unsigned long nr_pages);
331extern int vm_swappiness;
332extern int remove_mapping(struct address_space *mapping, struct page *page);
333extern unsigned long vm_total_pages;
334
335#ifdef CONFIG_NUMA
336extern int zone_reclaim_mode;
337extern int sysctl_min_unmapped_ratio;
338extern int sysctl_min_slab_ratio;
339extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
340#else
341#define zone_reclaim_mode 0
342static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
343{
344 return 0;
345}
346#endif
347
348extern int page_evictable(struct page *page);
349extern void check_move_unevictable_pages(struct page **, int nr_pages);
350
351extern int kswapd_run(int nid);
352extern void kswapd_stop(int nid);
353
354#ifdef CONFIG_SWAP
355
356extern int swap_readpage(struct page *);
357extern int swap_writepage(struct page *page, struct writeback_control *wbc);
358extern void end_swap_bio_write(struct bio *bio);
359extern int __swap_writepage(struct page *page, struct writeback_control *wbc,
360 bio_end_io_t end_write_func);
361extern int swap_set_page_dirty(struct page *page);
362
363int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
364 unsigned long nr_pages, sector_t start_block);
365int generic_swapfile_activate(struct swap_info_struct *, struct file *,
366 sector_t *);
367
368
369extern struct address_space swapper_spaces[];
370#define swap_address_space(entry) (&swapper_spaces[swp_type(entry)])
371extern unsigned long total_swapcache_pages(void);
372extern void show_swap_cache_info(void);
373extern int add_to_swap(struct page *, struct list_head *list);
374extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
375extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
376extern void __delete_from_swap_cache(struct page *);
377extern void delete_from_swap_cache(struct page *);
378extern void free_page_and_swap_cache(struct page *);
379extern void free_pages_and_swap_cache(struct page **, int);
380extern struct page *lookup_swap_cache(swp_entry_t);
381extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
382 struct vm_area_struct *vma, unsigned long addr);
383extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t,
384 struct vm_area_struct *vma, unsigned long addr,
385 bool *new_page_allocated);
386extern struct page *swapin_readahead(swp_entry_t, gfp_t,
387 struct vm_area_struct *vma, unsigned long addr);
388
389
390extern atomic_long_t nr_swap_pages;
391extern long total_swap_pages;
392
393
394static inline bool vm_swap_full(void)
395{
396 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
397}
398
399static inline long get_nr_swap_pages(void)
400{
401 return atomic_long_read(&nr_swap_pages);
402}
403
404extern void si_swapinfo(struct sysinfo *);
405extern swp_entry_t get_swap_page(void);
406extern swp_entry_t get_swap_page_of_type(int);
407extern int add_swap_count_continuation(swp_entry_t, gfp_t);
408extern void swap_shmem_alloc(swp_entry_t);
409extern int swap_duplicate(swp_entry_t);
410extern int swapcache_prepare(swp_entry_t);
411extern void swap_free(swp_entry_t);
412extern void swapcache_free(swp_entry_t);
413extern int free_swap_and_cache(swp_entry_t);
414extern int swap_type_of(dev_t, sector_t, struct block_device **);
415extern unsigned int count_swap_pages(int, int);
416extern sector_t map_swap_page(struct page *, struct block_device **);
417extern sector_t swapdev_block(int, pgoff_t);
418extern int page_swapcount(struct page *);
419extern int swp_swapcount(swp_entry_t entry);
420extern struct swap_info_struct *page_swap_info(struct page *);
421extern bool reuse_swap_page(struct page *, int *);
422extern int try_to_free_swap(struct page *);
423struct backing_dev_info;
424
425#else
426
427#define swap_address_space(entry) (NULL)
428#define get_nr_swap_pages() 0L
429#define total_swap_pages 0L
430#define total_swapcache_pages() 0UL
431#define vm_swap_full() 0
432
433#define si_swapinfo(val) \
434 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
435
436
437#define free_page_and_swap_cache(page) \
438 put_page(page)
439#define free_pages_and_swap_cache(pages, nr) \
440 release_pages((pages), (nr), false);
441
442static inline void show_swap_cache_info(void)
443{
444}
445
446#define free_swap_and_cache(swp) is_migration_entry(swp)
447#define swapcache_prepare(swp) is_migration_entry(swp)
448
449static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
450{
451 return 0;
452}
453
454static inline void swap_shmem_alloc(swp_entry_t swp)
455{
456}
457
458static inline int swap_duplicate(swp_entry_t swp)
459{
460 return 0;
461}
462
463static inline void swap_free(swp_entry_t swp)
464{
465}
466
467static inline void swapcache_free(swp_entry_t swp)
468{
469}
470
471static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
472 struct vm_area_struct *vma, unsigned long addr)
473{
474 return NULL;
475}
476
477static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
478{
479 return 0;
480}
481
482static inline struct page *lookup_swap_cache(swp_entry_t swp)
483{
484 return NULL;
485}
486
487static inline int add_to_swap(struct page *page, struct list_head *list)
488{
489 return 0;
490}
491
492static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
493 gfp_t gfp_mask)
494{
495 return -1;
496}
497
498static inline void __delete_from_swap_cache(struct page *page)
499{
500}
501
502static inline void delete_from_swap_cache(struct page *page)
503{
504}
505
506static inline int page_swapcount(struct page *page)
507{
508 return 0;
509}
510
511static inline int swp_swapcount(swp_entry_t entry)
512{
513 return 0;
514}
515
516#define reuse_swap_page(page, total_mapcount) \
517 (page_trans_huge_mapcount(page, total_mapcount) == 1)
518
519static inline int try_to_free_swap(struct page *page)
520{
521 return 0;
522}
523
524static inline swp_entry_t get_swap_page(void)
525{
526 swp_entry_t entry;
527 entry.val = 0;
528 return entry;
529}
530
531#endif
532
533#ifdef CONFIG_MEMCG
534static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
535{
536
537 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
538 return vm_swappiness;
539
540
541 if (mem_cgroup_disabled() || !memcg->css.parent)
542 return vm_swappiness;
543
544 return memcg->swappiness;
545}
546
547#else
548static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
549{
550 return vm_swappiness;
551}
552#endif
553
554#ifdef CONFIG_MEMCG_SWAP
555extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);
556extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);
557extern void mem_cgroup_uncharge_swap(swp_entry_t entry);
558extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
559extern bool mem_cgroup_swap_full(struct page *page);
560#else
561static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
562{
563}
564
565static inline int mem_cgroup_try_charge_swap(struct page *page,
566 swp_entry_t entry)
567{
568 return 0;
569}
570
571static inline void mem_cgroup_uncharge_swap(swp_entry_t entry)
572{
573}
574
575static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
576{
577 return get_nr_swap_pages();
578}
579
580static inline bool mem_cgroup_swap_full(struct page *page)
581{
582 return vm_swap_full();
583}
584#endif
585
586#endif
587#endif
588