1/* SPDX-License-Identifier: GPL-2.0 */
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/pagemap.h>
14#include <linux/atomic.h>
15#include <linux/page-flags.h>
16#include <uapi/linux/mempolicy.h>
17#include <asm/page.h>
18
19struct notifier_block;
20
21struct bio;
22
23struct pagevec;
24
25#define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
26#define SWAP_FLAG_PRIO_MASK 0x7fff
27#define SWAP_FLAG_PRIO_SHIFT 0
28#define SWAP_FLAG_DISCARD 0x10000 /* enable discard for swap */
29#define SWAP_FLAG_DISCARD_ONCE 0x20000 /* discard swap area at swapon-time */
30#define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */
31
32#define SWAP_FLAGS_VALID (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \
33 SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \
34 SWAP_FLAG_DISCARD_PAGES)
35#define SWAP_BATCH 64
36
37static inline int current_is_kswapd(void)
38{
39 return current->flags & PF_KSWAPD;
40}
41
42/*
43 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
44 * be swapped to. The swap type and the offset into that swap type are
45 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits
46 * for the type means that the maximum number of swapcache pages is 27 bits
47 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
48 * the type/offset into the pte as 5/27 as well.
49 */
50#define MAX_SWAPFILES_SHIFT 5
51
52/*
53 * Use some of the swap files numbers for other purposes. This
54 * is a convenient way to hook into the VM to trigger special
55 * actions on faults.
56 */
57
58/*
59 * PTE markers are used to persist information onto PTEs that otherwise
60 * should be a none pte. As its name "PTE" hints, it should only be
61 * applied to the leaves of pgtables.
62 */
63#define SWP_PTE_MARKER_NUM 1
64#define SWP_PTE_MARKER (MAX_SWAPFILES + SWP_HWPOISON_NUM + \
65 SWP_MIGRATION_NUM + SWP_DEVICE_NUM)
66
67/*
68 * Unaddressable device memory support. See include/linux/hmm.h and
69 * Documentation/mm/hmm.rst. Short description is we need struct pages for
70 * device memory that is unaddressable (inaccessible) by CPU, so that we can
71 * migrate part of a process memory to device memory.
72 *
73 * When a page is migrated from CPU to device, we set the CPU page table entry
74 * to a special SWP_DEVICE_{READ|WRITE} entry.
75 *
76 * When a page is mapped by the device for exclusive access we set the CPU page
77 * table entries to special SWP_DEVICE_EXCLUSIVE_* entries.
78 */
79#ifdef CONFIG_DEVICE_PRIVATE
80#define SWP_DEVICE_NUM 4
81#define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM)
82#define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1)
83#define SWP_DEVICE_EXCLUSIVE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2)
84#define SWP_DEVICE_EXCLUSIVE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+3)
85#else
86#define SWP_DEVICE_NUM 0
87#endif
88
89/*
90 * Page migration support.
91 *
92 * SWP_MIGRATION_READ_EXCLUSIVE is only applicable to anonymous pages and
93 * indicates that the referenced (part of) an anonymous page is exclusive to
94 * a single process. For SWP_MIGRATION_WRITE, that information is implicit:
95 * (part of) an anonymous page that are mapped writable are exclusive to a
96 * single process.
97 */
98#ifdef CONFIG_MIGRATION
99#define SWP_MIGRATION_NUM 3
100#define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
101#define SWP_MIGRATION_READ_EXCLUSIVE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
102#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 2)
103#else
104#define SWP_MIGRATION_NUM 0
105#endif
106
107/*
108 * Handling of hardware poisoned pages with memory corruption.
109 */
110#ifdef CONFIG_MEMORY_FAILURE
111#define SWP_HWPOISON_NUM 1
112#define SWP_HWPOISON MAX_SWAPFILES
113#else
114#define SWP_HWPOISON_NUM 0
115#endif
116
117#define MAX_SWAPFILES \
118 ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \
119 SWP_MIGRATION_NUM - SWP_HWPOISON_NUM - \
120 SWP_PTE_MARKER_NUM)
121
122/*
123 * Magic header for a swap area. The first part of the union is
124 * what the swap magic looks like for the old (limited to 128MB)
125 * swap area format, the second part of the union adds - in the
126 * old reserved area - some extra information. Note that the first
127 * kilobyte is reserved for boot loader or disk label stuff...
128 *
129 * Having the magic at the end of the PAGE_SIZE makes detecting swap
130 * areas somewhat tricky on machines that support multiple page sizes.
131 * For 2.5 we'll probably want to move the magic to just beyond the
132 * bootbits...
133 */
134union swap_header {
135 struct {
136 char reserved[PAGE_SIZE - 10];
137 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
138 } magic;
139 struct {
140 char bootbits[1024]; /* Space for disklabel etc. */
141 __u32 version;
142 __u32 last_page;
143 __u32 nr_badpages;
144 unsigned char sws_uuid[16];
145 unsigned char sws_volume[16];
146 __u32 padding[117];
147 __u32 badpages[1];
148 } info;
149};
150
151/*
152 * current->reclaim_state points to one of these when a task is running
153 * memory reclaim
154 */
155struct reclaim_state {
156 /* pages reclaimed outside of LRU-based reclaim */
157 unsigned long reclaimed;
158#ifdef CONFIG_LRU_GEN
159 /* per-thread mm walk data */
160 struct lru_gen_mm_walk *mm_walk;
161#endif
162};
163
164/*
165 * mm_account_reclaimed_pages(): account reclaimed pages outside of LRU-based
166 * reclaim
167 * @pages: number of pages reclaimed
168 *
169 * If the current process is undergoing a reclaim operation, increment the
170 * number of reclaimed pages by @pages.
171 */
172static inline void mm_account_reclaimed_pages(unsigned long pages)
173{
174 if (current->reclaim_state)
175 current->reclaim_state->reclaimed += pages;
176}
177
178#ifdef __KERNEL__
179
180struct address_space;
181struct sysinfo;
182struct writeback_control;
183struct zone;
184
185/*
186 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
187 * disk blocks. A rbtree of swap extents maps the entire swapfile (Where the
188 * term `swapfile' refers to either a blockdevice or an IS_REG file). Apart
189 * from setup, they're handled identically.
190 *
191 * We always assume that blocks are of size PAGE_SIZE.
192 */
193struct swap_extent {
194 struct rb_node rb_node;
195 pgoff_t start_page;
196 pgoff_t nr_pages;
197 sector_t start_block;
198};
199
200/*
201 * Max bad pages in the new format..
202 */
203#define MAX_SWAP_BADPAGES \
204 ((offsetof(union swap_header, magic.magic) - \
205 offsetof(union swap_header, info.badpages)) / sizeof(int))
206
207enum {
208 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
209 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
210 SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */
211 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
212 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
213 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
214 SWP_BLKDEV = (1 << 6), /* its a block device */
215 SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */
216 SWP_FS_OPS = (1 << 8), /* swapfile operations go through fs */
217 SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */
218 SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */
219 SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */
220 SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */
221 /* add others here before... */
222 SWP_SCANNING = (1 << 14), /* refcount in scan_swap_map */
223};
224
225#define SWAP_CLUSTER_MAX 32UL
226#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
227
228/* Bit flag in swap_map */
229#define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
230#define COUNT_CONTINUED 0x80 /* Flag swap_map continuation for full count */
231
232/* Special value in first swap_map */
233#define SWAP_MAP_MAX 0x3e /* Max count */
234#define SWAP_MAP_BAD 0x3f /* Note page is bad */
235#define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs */
236
237/* Special value in each swap_map continuation */
238#define SWAP_CONT_MAX 0x7f /* Max count */
239
240/*
241 * We use this to track usage of a cluster. A cluster is a block of swap disk
242 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All
243 * free clusters are organized into a list. We fetch an entry from the list to
244 * get a free cluster.
245 *
246 * The data field stores next cluster if the cluster is free or cluster usage
247 * counter otherwise. The flags field determines if a cluster is free. This is
248 * protected by swap_info_struct.lock.
249 */
250struct swap_cluster_info {
251 spinlock_t lock; /*
252 * Protect swap_cluster_info fields
253 * and swap_info_struct->swap_map
254 * elements correspond to the swap
255 * cluster
256 */
257 unsigned int data:24;
258 unsigned int flags:8;
259};
260#define CLUSTER_FLAG_FREE 1 /* This cluster is free */
261#define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */
262#define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */
263
264/*
265 * We assign a cluster to each CPU, so each CPU can allocate swap entry from
266 * its own cluster and swapout sequentially. The purpose is to optimize swapout
267 * throughput.
268 */
269struct percpu_cluster {
270 struct swap_cluster_info index; /* Current cluster index */
271 unsigned int next; /* Likely next allocation offset */
272};
273
274struct swap_cluster_list {
275 struct swap_cluster_info head;
276 struct swap_cluster_info tail;
277};
278
279/*
280 * The in-memory structure used to track swap areas.
281 */
282struct swap_info_struct {
283 struct percpu_ref users; /* indicate and keep swap device valid. */
284 unsigned long flags; /* SWP_USED etc: see above */
285 signed short prio; /* swap priority of this type */
286 struct plist_node list; /* entry in swap_active_head */
287 signed char type; /* strange name for an index */
288 unsigned int max; /* extent of the swap_map */
289 unsigned char *swap_map; /* vmalloc'ed array of usage counts */
290 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
291 struct swap_cluster_list free_clusters; /* free clusters list */
292 unsigned int lowest_bit; /* index of first free in swap_map */
293 unsigned int highest_bit; /* index of last free in swap_map */
294 unsigned int pages; /* total of usable pages of swap */
295 unsigned int inuse_pages; /* number of those currently in use */
296 unsigned int cluster_next; /* likely index for next allocation */
297 unsigned int cluster_nr; /* countdown to next cluster search */
298 unsigned int __percpu *cluster_next_cpu; /*percpu index for next allocation */
299 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
300 struct rb_root swap_extent_root;/* root of the swap extent rbtree */
301 struct file *bdev_file; /* open handle of the bdev */
302 struct block_device *bdev; /* swap device or bdev of swap file */
303 struct file *swap_file; /* seldom referenced */
304 unsigned int old_block_size; /* seldom referenced */
305 struct completion comp; /* seldom referenced */
306 spinlock_t lock; /*
307 * protect map scan related fields like
308 * swap_map, lowest_bit, highest_bit,
309 * inuse_pages, cluster_next,
310 * cluster_nr, lowest_alloc,
311 * highest_alloc, free/discard cluster
312 * list. other fields are only changed
313 * at swapon/swapoff, so are protected
314 * by swap_lock. changing flags need
315 * hold this lock and swap_lock. If
316 * both locks need hold, hold swap_lock
317 * first.
318 */
319 spinlock_t cont_lock; /*
320 * protect swap count continuation page
321 * list.
322 */
323 struct work_struct discard_work; /* discard worker */
324 struct swap_cluster_list discard_clusters; /* discard clusters list */
325 struct plist_node avail_lists[]; /*
326 * entries in swap_avail_heads, one
327 * entry per node.
328 * Must be last as the number of the
329 * array is nr_node_ids, which is not
330 * a fixed value so have to allocate
331 * dynamically.
332 * And it has to be an array so that
333 * plist_for_each_* can work.
334 */
335};
336
337static inline swp_entry_t page_swap_entry(struct page *page)
338{
339 struct folio *folio = page_folio(page);
340 swp_entry_t entry = folio->swap;
341
342 entry.val += folio_page_idx(folio, page);
343 return entry;
344}
345
346/* linux/mm/workingset.c */
347bool workingset_test_recent(void *shadow, bool file, bool *workingset);
348void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages);
349void *workingset_eviction(struct folio *folio, struct mem_cgroup *target_memcg);
350void workingset_refault(struct folio *folio, void *shadow);
351void workingset_activation(struct folio *folio);
352
353/* linux/mm/page_alloc.c */
354extern unsigned long totalreserve_pages;
355
356/* Definition of global_zone_page_state not available yet */
357#define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
358
359
360/* linux/mm/swap.c */
361void lru_note_cost(struct lruvec *lruvec, bool file,
362 unsigned int nr_io, unsigned int nr_rotated);
363void lru_note_cost_refault(struct folio *);
364void folio_add_lru(struct folio *);
365void folio_add_lru_vma(struct folio *, struct vm_area_struct *);
366void mark_page_accessed(struct page *);
367void folio_mark_accessed(struct folio *);
368
369extern atomic_t lru_disable_count;
370
371static inline bool lru_cache_disabled(void)
372{
373 return atomic_read(v: &lru_disable_count);
374}
375
376static inline void lru_cache_enable(void)
377{
378 atomic_dec(v: &lru_disable_count);
379}
380
381extern void lru_cache_disable(void);
382extern void lru_add_drain(void);
383extern void lru_add_drain_cpu(int cpu);
384extern void lru_add_drain_cpu_zone(struct zone *zone);
385extern void lru_add_drain_all(void);
386void folio_deactivate(struct folio *folio);
387void folio_mark_lazyfree(struct folio *folio);
388extern void swap_setup(void);
389
390/* linux/mm/vmscan.c */
391extern unsigned long zone_reclaimable_pages(struct zone *zone);
392extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
393 gfp_t gfp_mask, nodemask_t *mask);
394
395#define MEMCG_RECLAIM_MAY_SWAP (1 << 1)
396#define MEMCG_RECLAIM_PROACTIVE (1 << 2)
397extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
398 unsigned long nr_pages,
399 gfp_t gfp_mask,
400 unsigned int reclaim_options);
401extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
402 gfp_t gfp_mask, bool noswap,
403 pg_data_t *pgdat,
404 unsigned long *nr_scanned);
405extern unsigned long shrink_all_memory(unsigned long nr_pages);
406extern int vm_swappiness;
407long remove_mapping(struct address_space *mapping, struct folio *folio);
408
409#ifdef CONFIG_NUMA
410extern int node_reclaim_mode;
411extern int sysctl_min_unmapped_ratio;
412extern int sysctl_min_slab_ratio;
413#else
414#define node_reclaim_mode 0
415#endif
416
417static inline bool node_reclaim_enabled(void)
418{
419 /* Is any node_reclaim_mode bit set? */
420 return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP);
421}
422
423void check_move_unevictable_folios(struct folio_batch *fbatch);
424
425extern void __meminit kswapd_run(int nid);
426extern void __meminit kswapd_stop(int nid);
427
428#ifdef CONFIG_SWAP
429
430int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
431 unsigned long nr_pages, sector_t start_block);
432int generic_swapfile_activate(struct swap_info_struct *, struct file *,
433 sector_t *);
434
435static inline unsigned long total_swapcache_pages(void)
436{
437 return global_node_page_state(item: NR_SWAPCACHE);
438}
439
440void free_swap_cache(struct folio *folio);
441void free_page_and_swap_cache(struct page *);
442void free_pages_and_swap_cache(struct encoded_page **, int);
443/* linux/mm/swapfile.c */
444extern atomic_long_t nr_swap_pages;
445extern long total_swap_pages;
446extern atomic_t nr_rotate_swap;
447extern bool has_usable_swap(void);
448
449/* Swap 50% full? Release swapcache more aggressively.. */
450static inline bool vm_swap_full(void)
451{
452 return atomic_long_read(v: &nr_swap_pages) * 2 < total_swap_pages;
453}
454
455static inline long get_nr_swap_pages(void)
456{
457 return atomic_long_read(v: &nr_swap_pages);
458}
459
460extern void si_swapinfo(struct sysinfo *);
461swp_entry_t folio_alloc_swap(struct folio *folio);
462bool folio_free_swap(struct folio *folio);
463void put_swap_folio(struct folio *folio, swp_entry_t entry);
464extern swp_entry_t get_swap_page_of_type(int);
465extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size);
466extern int add_swap_count_continuation(swp_entry_t, gfp_t);
467extern void swap_shmem_alloc(swp_entry_t);
468extern int swap_duplicate(swp_entry_t);
469extern int swapcache_prepare(swp_entry_t);
470extern void swap_free(swp_entry_t);
471extern void swapcache_free_entries(swp_entry_t *entries, int n);
472extern int free_swap_and_cache(swp_entry_t);
473int swap_type_of(dev_t device, sector_t offset);
474int find_first_swap(dev_t *device);
475extern unsigned int count_swap_pages(int, int);
476extern sector_t swapdev_block(int, pgoff_t);
477extern int __swap_count(swp_entry_t entry);
478extern int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry);
479extern int swp_swapcount(swp_entry_t entry);
480struct swap_info_struct *swp_swap_info(swp_entry_t entry);
481struct backing_dev_info;
482extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
483extern void exit_swap_address_space(unsigned int type);
484extern struct swap_info_struct *get_swap_device(swp_entry_t entry);
485sector_t swap_folio_sector(struct folio *folio);
486
487static inline void put_swap_device(struct swap_info_struct *si)
488{
489 percpu_ref_put(ref: &si->users);
490}
491
492#else /* CONFIG_SWAP */
493static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry)
494{
495 return NULL;
496}
497
498static inline struct swap_info_struct *get_swap_device(swp_entry_t entry)
499{
500 return NULL;
501}
502
503static inline void put_swap_device(struct swap_info_struct *si)
504{
505}
506
507#define get_nr_swap_pages() 0L
508#define total_swap_pages 0L
509#define total_swapcache_pages() 0UL
510#define vm_swap_full() 0
511
512#define si_swapinfo(val) \
513 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
514/* only sparc can not include linux/pagemap.h in this file
515 * so leave put_page and release_pages undeclared... */
516#define free_page_and_swap_cache(page) \
517 put_page(page)
518#define free_pages_and_swap_cache(pages, nr) \
519 release_pages((pages), (nr));
520
521/* used to sanity check ptes in zap_pte_range when CONFIG_SWAP=0 */
522#define free_swap_and_cache(e) is_pfn_swap_entry(e)
523
524static inline void free_swap_cache(struct folio *folio)
525{
526}
527
528static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
529{
530 return 0;
531}
532
533static inline void swap_shmem_alloc(swp_entry_t swp)
534{
535}
536
537static inline int swap_duplicate(swp_entry_t swp)
538{
539 return 0;
540}
541
542static inline int swapcache_prepare(swp_entry_t swp)
543{
544 return 0;
545}
546
547static inline void swap_free(swp_entry_t swp)
548{
549}
550
551static inline void put_swap_folio(struct folio *folio, swp_entry_t swp)
552{
553}
554
555static inline int __swap_count(swp_entry_t entry)
556{
557 return 0;
558}
559
560static inline int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry)
561{
562 return 0;
563}
564
565static inline int swp_swapcount(swp_entry_t entry)
566{
567 return 0;
568}
569
570static inline swp_entry_t folio_alloc_swap(struct folio *folio)
571{
572 swp_entry_t entry;
573 entry.val = 0;
574 return entry;
575}
576
577static inline bool folio_free_swap(struct folio *folio)
578{
579 return false;
580}
581
582static inline int add_swap_extent(struct swap_info_struct *sis,
583 unsigned long start_page,
584 unsigned long nr_pages, sector_t start_block)
585{
586 return -EINVAL;
587}
588#endif /* CONFIG_SWAP */
589
590#ifdef CONFIG_THP_SWAP
591extern int split_swap_cluster(swp_entry_t entry);
592#else
593static inline int split_swap_cluster(swp_entry_t entry)
594{
595 return 0;
596}
597#endif
598
599#ifdef CONFIG_MEMCG
600static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
601{
602 /* Cgroup2 doesn't have per-cgroup swappiness */
603 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
604 return READ_ONCE(vm_swappiness);
605
606 /* root ? */
607 if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg))
608 return READ_ONCE(vm_swappiness);
609
610 return READ_ONCE(memcg->swappiness);
611}
612#else
613static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
614{
615 return READ_ONCE(vm_swappiness);
616}
617#endif
618
619#if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
620void __folio_throttle_swaprate(struct folio *folio, gfp_t gfp);
621static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp)
622{
623 if (mem_cgroup_disabled())
624 return;
625 __folio_throttle_swaprate(folio, gfp);
626}
627#else
628static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp)
629{
630}
631#endif
632
633#if defined(CONFIG_MEMCG) && defined(CONFIG_SWAP)
634void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry);
635int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry);
636static inline int mem_cgroup_try_charge_swap(struct folio *folio,
637 swp_entry_t entry)
638{
639 if (mem_cgroup_disabled())
640 return 0;
641 return __mem_cgroup_try_charge_swap(folio, entry);
642}
643
644extern void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
645static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
646{
647 if (mem_cgroup_disabled())
648 return;
649 __mem_cgroup_uncharge_swap(entry, nr_pages);
650}
651
652extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
653extern bool mem_cgroup_swap_full(struct folio *folio);
654#else
655static inline void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry)
656{
657}
658
659static inline int mem_cgroup_try_charge_swap(struct folio *folio,
660 swp_entry_t entry)
661{
662 return 0;
663}
664
665static inline void mem_cgroup_uncharge_swap(swp_entry_t entry,
666 unsigned int nr_pages)
667{
668}
669
670static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
671{
672 return get_nr_swap_pages();
673}
674
675static inline bool mem_cgroup_swap_full(struct folio *folio)
676{
677 return vm_swap_full();
678}
679#endif
680
681#endif /* __KERNEL__*/
682#endif /* _LINUX_SWAP_H */
683

source code of linux/include/linux/swap.h