1
2#ifndef _LINUX_SWAP_H
3#define _LINUX_SWAP_H
4
5#include <linux/spinlock.h>
6#include <linux/linkage.h>
7#include <linux/mmzone.h>
8#include <linux/list.h>
9#include <linux/memcontrol.h>
10#include <linux/sched.h>
11#include <linux/node.h>
12#include <linux/fs.h>
13#include <linux/atomic.h>
14#include <linux/page-flags.h>
15#include <asm/page.h>
16
17struct notifier_block;
18
19struct bio;
20
21struct pagevec;
22
23#define SWAP_FLAG_PREFER 0x8000
24#define SWAP_FLAG_PRIO_MASK 0x7fff
25#define SWAP_FLAG_PRIO_SHIFT 0
26#define SWAP_FLAG_DISCARD 0x10000
27#define SWAP_FLAG_DISCARD_ONCE 0x20000
28#define SWAP_FLAG_DISCARD_PAGES 0x40000
29
30#define SWAP_FLAGS_VALID (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \
31 SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \
32 SWAP_FLAG_DISCARD_PAGES)
33#define SWAP_BATCH 64
34
35static inline int current_is_kswapd(void)
36{
37 return current->flags & PF_KSWAPD;
38}
39
40
41
42
43
44
45
46
47
48#define MAX_SWAPFILES_SHIFT 5
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65#ifdef CONFIG_DEVICE_PRIVATE
66#define SWP_DEVICE_NUM 2
67#define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM)
68#define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1)
69#else
70#define SWP_DEVICE_NUM 0
71#endif
72
73
74
75
76#ifdef CONFIG_MIGRATION
77#define SWP_MIGRATION_NUM 2
78#define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
79#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
80#else
81#define SWP_MIGRATION_NUM 0
82#endif
83
84
85
86
87#ifdef CONFIG_MEMORY_FAILURE
88#define SWP_HWPOISON_NUM 1
89#define SWP_HWPOISON MAX_SWAPFILES
90#else
91#define SWP_HWPOISON_NUM 0
92#endif
93
94#define MAX_SWAPFILES \
95 ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \
96 SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)
97
98
99
100
101
102
103
104
105
106
107
108
109
110union swap_header {
111 struct {
112 char reserved[PAGE_SIZE - 10];
113 char magic[10];
114 } magic;
115 struct {
116 char bootbits[1024];
117 __u32 version;
118 __u32 last_page;
119 __u32 nr_badpages;
120 unsigned char sws_uuid[16];
121 unsigned char sws_volume[16];
122 __u32 padding[117];
123 __u32 badpages[1];
124 } info;
125};
126
127
128
129
130
131struct reclaim_state {
132 unsigned long reclaimed_slab;
133};
134
135#ifdef __KERNEL__
136
137struct address_space;
138struct sysinfo;
139struct writeback_control;
140struct zone;
141
142
143
144
145
146
147
148
149
150struct swap_extent {
151 struct rb_node rb_node;
152 pgoff_t start_page;
153 pgoff_t nr_pages;
154 sector_t start_block;
155};
156
157
158
159
160#define MAX_SWAP_BADPAGES \
161 ((offsetof(union swap_header, magic.magic) - \
162 offsetof(union swap_header, info.badpages)) / sizeof(int))
163
164enum {
165 SWP_USED = (1 << 0),
166 SWP_WRITEOK = (1 << 1),
167 SWP_DISCARDABLE = (1 << 2),
168 SWP_DISCARDING = (1 << 3),
169 SWP_SOLIDSTATE = (1 << 4),
170 SWP_CONTINUED = (1 << 5),
171 SWP_BLKDEV = (1 << 6),
172 SWP_ACTIVATED = (1 << 7),
173 SWP_FS = (1 << 8),
174 SWP_AREA_DISCARD = (1 << 9),
175 SWP_PAGE_DISCARD = (1 << 10),
176 SWP_STABLE_WRITES = (1 << 11),
177 SWP_SYNCHRONOUS_IO = (1 << 12),
178 SWP_VALID = (1 << 13),
179
180 SWP_SCANNING = (1 << 14),
181};
182
183#define SWAP_CLUSTER_MAX 32UL
184#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
185
186#define SWAP_MAP_MAX 0x3e
187#define SWAP_MAP_BAD 0x3f
188#define SWAP_HAS_CACHE 0x40
189#define SWAP_CONT_MAX 0x7f
190#define COUNT_CONTINUED 0x80
191#define SWAP_MAP_SHMEM 0xbf
192
193
194
195
196
197
198
199
200
201
202
203struct swap_cluster_info {
204 spinlock_t lock;
205
206
207
208
209
210 unsigned int data:24;
211 unsigned int flags:8;
212};
213#define CLUSTER_FLAG_FREE 1
214#define CLUSTER_FLAG_NEXT_NULL 2
215#define CLUSTER_FLAG_HUGE 4
216
217
218
219
220
221
222struct percpu_cluster {
223 struct swap_cluster_info index;
224 unsigned int next;
225};
226
227struct swap_cluster_list {
228 struct swap_cluster_info head;
229 struct swap_cluster_info tail;
230};
231
232
233
234
235struct swap_info_struct {
236 unsigned long flags;
237 signed short prio;
238 struct plist_node list;
239 signed char type;
240 unsigned int max;
241 unsigned char *swap_map;
242 struct swap_cluster_info *cluster_info;
243 struct swap_cluster_list free_clusters;
244 unsigned int lowest_bit;
245 unsigned int highest_bit;
246 unsigned int pages;
247 unsigned int inuse_pages;
248 unsigned int cluster_next;
249 unsigned int cluster_nr;
250 struct percpu_cluster __percpu *percpu_cluster;
251 struct rb_root swap_extent_root;
252 struct block_device *bdev;
253 struct file *swap_file;
254 unsigned int old_block_size;
255#ifdef CONFIG_FRONTSWAP
256 unsigned long *frontswap_map;
257 atomic_t frontswap_pages;
258#endif
259 spinlock_t lock;
260
261
262
263
264
265
266
267
268
269
270
271
272 spinlock_t cont_lock;
273
274
275
276 struct work_struct discard_work;
277 struct swap_cluster_list discard_clusters;
278 struct plist_node avail_lists[0];
279
280
281
282
283
284
285
286
287
288};
289
290#ifdef CONFIG_64BIT
291#define SWAP_RA_ORDER_CEILING 5
292#else
293
294#define SWAP_RA_ORDER_CEILING 3
295#define SWAP_RA_PTE_CACHE_SIZE (1 << SWAP_RA_ORDER_CEILING)
296#endif
297
298struct vma_swap_readahead {
299 unsigned short win;
300 unsigned short offset;
301 unsigned short nr_pte;
302#ifdef CONFIG_64BIT
303 pte_t *ptes;
304#else
305 pte_t ptes[SWAP_RA_PTE_CACHE_SIZE];
306#endif
307};
308
309
310void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg);
311void workingset_refault(struct page *page, void *shadow);
312void workingset_activation(struct page *page);
313
314
315void workingset_update_node(struct xa_node *node);
316#define mapping_set_update(xas, mapping) do { \
317 if (!dax_mapping(mapping) && !shmem_mapping(mapping)) \
318 xas_set_update(xas, workingset_update_node); \
319} while (0)
320
321
322extern unsigned long totalreserve_pages;
323extern unsigned long nr_free_buffer_pages(void);
324extern unsigned long nr_free_pagecache_pages(void);
325
326
327#define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
328
329
330
331extern void lru_cache_add(struct page *);
332extern void lru_cache_add_anon(struct page *page);
333extern void lru_cache_add_file(struct page *page);
334extern void lru_add_page_tail(struct page *page, struct page *page_tail,
335 struct lruvec *lruvec, struct list_head *head);
336extern void activate_page(struct page *);
337extern void mark_page_accessed(struct page *);
338extern void lru_add_drain(void);
339extern void lru_add_drain_cpu(int cpu);
340extern void lru_add_drain_all(void);
341extern void rotate_reclaimable_page(struct page *page);
342extern void deactivate_file_page(struct page *page);
343extern void deactivate_page(struct page *page);
344extern void mark_page_lazyfree(struct page *page);
345extern void swap_setup(void);
346
347extern void lru_cache_add_active_or_unevictable(struct page *page,
348 struct vm_area_struct *vma);
349
350
351extern unsigned long zone_reclaimable_pages(struct zone *zone);
352extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
353 gfp_t gfp_mask, nodemask_t *mask);
354extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
355extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
356 unsigned long nr_pages,
357 gfp_t gfp_mask,
358 bool may_swap);
359extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
360 gfp_t gfp_mask, bool noswap,
361 pg_data_t *pgdat,
362 unsigned long *nr_scanned);
363extern unsigned long shrink_all_memory(unsigned long nr_pages);
364extern int vm_swappiness;
365extern int remove_mapping(struct address_space *mapping, struct page *page);
366extern unsigned long vm_total_pages;
367
368extern unsigned long reclaim_pages(struct list_head *page_list);
369#ifdef CONFIG_NUMA
370extern int node_reclaim_mode;
371extern int sysctl_min_unmapped_ratio;
372extern int sysctl_min_slab_ratio;
373#else
374#define node_reclaim_mode 0
375#endif
376
377extern int page_evictable(struct page *page);
378extern void check_move_unevictable_pages(struct pagevec *pvec);
379
380extern int kswapd_run(int nid);
381extern void kswapd_stop(int nid);
382
383#ifdef CONFIG_SWAP
384
385#include <linux/blk_types.h>
386
387
388extern int swap_readpage(struct page *page, bool do_poll);
389extern int swap_writepage(struct page *page, struct writeback_control *wbc);
390extern void end_swap_bio_write(struct bio *bio);
391extern int __swap_writepage(struct page *page, struct writeback_control *wbc,
392 bio_end_io_t end_write_func);
393extern int swap_set_page_dirty(struct page *page);
394
395int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
396 unsigned long nr_pages, sector_t start_block);
397int generic_swapfile_activate(struct swap_info_struct *, struct file *,
398 sector_t *);
399
400
401
402#define SWAP_ADDRESS_SPACE_SHIFT 14
403#define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT)
404extern struct address_space *swapper_spaces[];
405#define swap_address_space(entry) \
406 (&swapper_spaces[swp_type(entry)][swp_offset(entry) \
407 >> SWAP_ADDRESS_SPACE_SHIFT])
408extern unsigned long total_swapcache_pages(void);
409extern void show_swap_cache_info(void);
410extern int add_to_swap(struct page *page);
411extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
412extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
413extern void __delete_from_swap_cache(struct page *, swp_entry_t entry);
414extern void delete_from_swap_cache(struct page *);
415extern void free_page_and_swap_cache(struct page *);
416extern void free_pages_and_swap_cache(struct page **, int);
417extern struct page *lookup_swap_cache(swp_entry_t entry,
418 struct vm_area_struct *vma,
419 unsigned long addr);
420extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
421 struct vm_area_struct *vma, unsigned long addr,
422 bool do_poll);
423extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t,
424 struct vm_area_struct *vma, unsigned long addr,
425 bool *new_page_allocated);
426extern struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
427 struct vm_fault *vmf);
428extern struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
429 struct vm_fault *vmf);
430
431
432extern atomic_long_t nr_swap_pages;
433extern long total_swap_pages;
434extern atomic_t nr_rotate_swap;
435extern bool has_usable_swap(void);
436
437
438static inline bool vm_swap_full(void)
439{
440 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
441}
442
443static inline long get_nr_swap_pages(void)
444{
445 return atomic_long_read(&nr_swap_pages);
446}
447
448extern void si_swapinfo(struct sysinfo *);
449extern swp_entry_t get_swap_page(struct page *page);
450extern void put_swap_page(struct page *page, swp_entry_t entry);
451extern swp_entry_t get_swap_page_of_type(int);
452extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size);
453extern int add_swap_count_continuation(swp_entry_t, gfp_t);
454extern void swap_shmem_alloc(swp_entry_t);
455extern int swap_duplicate(swp_entry_t);
456extern int swapcache_prepare(swp_entry_t);
457extern void swap_free(swp_entry_t);
458extern void swapcache_free_entries(swp_entry_t *entries, int n);
459extern int free_swap_and_cache(swp_entry_t);
460extern int swap_type_of(dev_t, sector_t, struct block_device **);
461extern unsigned int count_swap_pages(int, int);
462extern sector_t map_swap_page(struct page *, struct block_device **);
463extern sector_t swapdev_block(int, pgoff_t);
464extern int page_swapcount(struct page *);
465extern int __swap_count(swp_entry_t entry);
466extern int __swp_swapcount(swp_entry_t entry);
467extern int swp_swapcount(swp_entry_t entry);
468extern struct swap_info_struct *page_swap_info(struct page *);
469extern struct swap_info_struct *swp_swap_info(swp_entry_t entry);
470extern bool reuse_swap_page(struct page *, int *);
471extern int try_to_free_swap(struct page *);
472struct backing_dev_info;
473extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
474extern void exit_swap_address_space(unsigned int type);
475extern struct swap_info_struct *get_swap_device(swp_entry_t entry);
476
477static inline void put_swap_device(struct swap_info_struct *si)
478{
479 rcu_read_unlock();
480}
481
482#else
483
484static inline int swap_readpage(struct page *page, bool do_poll)
485{
486 return 0;
487}
488
489static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry)
490{
491 return NULL;
492}
493
494#define swap_address_space(entry) (NULL)
495#define get_nr_swap_pages() 0L
496#define total_swap_pages 0L
497#define total_swapcache_pages() 0UL
498#define vm_swap_full() 0
499
500#define si_swapinfo(val) \
501 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
502
503
504#define free_page_and_swap_cache(page) \
505 put_page(page)
506#define free_pages_and_swap_cache(pages, nr) \
507 release_pages((pages), (nr));
508
509static inline void show_swap_cache_info(void)
510{
511}
512
513#define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
514#define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
515
516static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
517{
518 return 0;
519}
520
521static inline void swap_shmem_alloc(swp_entry_t swp)
522{
523}
524
525static inline int swap_duplicate(swp_entry_t swp)
526{
527 return 0;
528}
529
530static inline void swap_free(swp_entry_t swp)
531{
532}
533
534static inline void put_swap_page(struct page *page, swp_entry_t swp)
535{
536}
537
538static inline struct page *swap_cluster_readahead(swp_entry_t entry,
539 gfp_t gfp_mask, struct vm_fault *vmf)
540{
541 return NULL;
542}
543
544static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
545 struct vm_fault *vmf)
546{
547 return NULL;
548}
549
550static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
551{
552 return 0;
553}
554
555static inline struct page *lookup_swap_cache(swp_entry_t swp,
556 struct vm_area_struct *vma,
557 unsigned long addr)
558{
559 return NULL;
560}
561
562static inline int add_to_swap(struct page *page)
563{
564 return 0;
565}
566
567static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
568 gfp_t gfp_mask)
569{
570 return -1;
571}
572
573static inline void __delete_from_swap_cache(struct page *page,
574 swp_entry_t entry)
575{
576}
577
578static inline void delete_from_swap_cache(struct page *page)
579{
580}
581
582static inline int page_swapcount(struct page *page)
583{
584 return 0;
585}
586
587static inline int __swap_count(swp_entry_t entry)
588{
589 return 0;
590}
591
592static inline int __swp_swapcount(swp_entry_t entry)
593{
594 return 0;
595}
596
597static inline int swp_swapcount(swp_entry_t entry)
598{
599 return 0;
600}
601
602#define reuse_swap_page(page, total_map_swapcount) \
603 (page_trans_huge_mapcount(page, total_map_swapcount) == 1)
604
605static inline int try_to_free_swap(struct page *page)
606{
607 return 0;
608}
609
610static inline swp_entry_t get_swap_page(struct page *page)
611{
612 swp_entry_t entry;
613 entry.val = 0;
614 return entry;
615}
616
617#endif
618
619#ifdef CONFIG_THP_SWAP
620extern int split_swap_cluster(swp_entry_t entry);
621#else
622static inline int split_swap_cluster(swp_entry_t entry)
623{
624 return 0;
625}
626#endif
627
628#ifdef CONFIG_MEMCG
629static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
630{
631
632 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
633 return vm_swappiness;
634
635
636 if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg))
637 return vm_swappiness;
638
639 return memcg->swappiness;
640}
641#else
642static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
643{
644 return vm_swappiness;
645}
646#endif
647
648#if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
649extern void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg, int node,
650 gfp_t gfp_mask);
651#else
652static inline void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg,
653 int node, gfp_t gfp_mask)
654{
655}
656#endif
657
658#ifdef CONFIG_MEMCG_SWAP
659extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);
660extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);
661extern void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
662extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
663extern bool mem_cgroup_swap_full(struct page *page);
664#else
665static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
666{
667}
668
669static inline int mem_cgroup_try_charge_swap(struct page *page,
670 swp_entry_t entry)
671{
672 return 0;
673}
674
675static inline void mem_cgroup_uncharge_swap(swp_entry_t entry,
676 unsigned int nr_pages)
677{
678}
679
680static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
681{
682 return get_nr_swap_pages();
683}
684
685static inline bool mem_cgroup_swap_full(struct page *page)
686{
687 return vm_swap_full();
688}
689#endif
690
691#endif
692#endif
693