swap.h

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