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