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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/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 /* set if swap priority specified */
22#define SWAP_FLAG_PRIO_MASK 0x7fff
23#define SWAP_FLAG_PRIO_SHIFT 0
24#define SWAP_FLAG_DISCARD 0x10000 /* enable discard for swap */
25#define SWAP_FLAG_DISCARD_ONCE 0x20000 /* discard swap area at swapon-time */
26#define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */
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 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
40 * be swapped to. The swap type and the offset into that swap type are
41 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits
42 * for the type means that the maximum number of swapcache pages is 27 bits
43 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
44 * the type/offset into the pte as 5/27 as well.
45 */
46#define MAX_SWAPFILES_SHIFT 5
47
48/*
49 * Use some of the swap files numbers for other purposes. This
50 * is a convenient way to hook into the VM to trigger special
51 * actions on faults.
52 */
53
54/*
55 * Unaddressable device memory support. See include/linux/hmm.h and
56 * Documentation/vm/hmm.txt. Short description is we need struct pages for
57 * device memory that is unaddressable (inaccessible) by CPU, so that we can
58 * migrate part of a process memory to device memory.
59 *
60 * When a page is migrated from CPU to device, we set the CPU page table entry
61 * to a special SWP_DEVICE_* entry.
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 * NUMA node memory migration support
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 * Handling of hardware poisoned pages with memory corruption.
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 * Magic header for a swap area. The first part of the union is
98 * what the swap magic looks like for the old (limited to 128MB)
99 * swap area format, the second part of the union adds - in the
100 * old reserved area - some extra information. Note that the first
101 * kilobyte is reserved for boot loader or disk label stuff...
102 *
103 * Having the magic at the end of the PAGE_SIZE makes detecting swap
104 * areas somewhat tricky on machines that support multiple page sizes.
105 * For 2.5 we'll probably want to move the magic to just beyond the
106 * bootbits...
107 */
108union swap_header {
109 struct {
110 char reserved[PAGE_SIZE - 10];
111 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
112 } magic;
113 struct {
114 char bootbits[1024]; /* Space for disklabel etc. */
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 * current->reclaim_state points to one of these when a task is running
127 * memory reclaim
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 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
142 * disk blocks. A list of swap extents maps the entire swapfile. (Where the
143 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
144 * from setup, they're handled identically.
145 *
146 * We always assume that blocks are of size PAGE_SIZE.
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 * Max bad pages in the new format..
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), /* is slot in swap_info[] used? */
164 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
165 SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */
166 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
167 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
168 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
169 SWP_BLKDEV = (1 << 6), /* its a block device */
170 SWP_FILE = (1 << 7), /* set after swap_activate success */
171 SWP_AREA_DISCARD = (1 << 8), /* single-time swap area discards */
172 SWP_PAGE_DISCARD = (1 << 9), /* freed swap page-cluster discards */
173 SWP_STABLE_WRITES = (1 << 10), /* no overwrite PG_writeback pages */
174 SWP_SYNCHRONOUS_IO = (1 << 11), /* synchronous IO is efficient */
175 /* add others here before... */
176 SWP_SCANNING = (1 << 12), /* refcount in scan_swap_map */
177};
178
179#define SWAP_CLUSTER_MAX 32UL
180#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
181
182#define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */
183#define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */
184#define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
185#define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */
186#define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */
187#define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */
188
189/*
190 * We use this to track usage of a cluster. A cluster is a block of swap disk
191 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All
192 * free clusters are organized into a list. We fetch an entry from the list to
193 * get a free cluster.
194 *
195 * The data field stores next cluster if the cluster is free or cluster usage
196 * counter otherwise. The flags field determines if a cluster is free. This is
197 * protected by swap_info_struct.lock.
198 */
199struct swap_cluster_info {
200 spinlock_t lock; /*
201 * Protect swap_cluster_info fields
202 * and swap_info_struct->swap_map
203 * elements correspond to the swap
204 * cluster
205 */
206 unsigned int data:24;
207 unsigned int flags:8;
208};
209#define CLUSTER_FLAG_FREE 1 /* This cluster is free */
210#define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */
211#define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */
212
213/*
214 * We assign a cluster to each CPU, so each CPU can allocate swap entry from
215 * its own cluster and swapout sequentially. The purpose is to optimize swapout
216 * throughput.
217 */
218struct percpu_cluster {
219 struct swap_cluster_info index; /* Current cluster index */
220 unsigned int next; /* Likely next allocation offset */
221};
222
223struct swap_cluster_list {
224 struct swap_cluster_info head;
225 struct swap_cluster_info tail;
226};
227
228/*
229 * The in-memory structure used to track swap areas.
230 */
231struct swap_info_struct {
232 unsigned long flags; /* SWP_USED etc: see above */
233 signed short prio; /* swap priority of this type */
234 struct plist_node list; /* entry in swap_active_head */
235 struct plist_node avail_lists[MAX_NUMNODES];/* entry in swap_avail_heads */
236 signed char type; /* strange name for an index */
237 unsigned int max; /* extent of the swap_map */
238 unsigned char *swap_map; /* vmalloc'ed array of usage counts */
239 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
240 struct swap_cluster_list free_clusters; /* free clusters list */
241 unsigned int lowest_bit; /* index of first free in swap_map */
242 unsigned int highest_bit; /* index of last free in swap_map */
243 unsigned int pages; /* total of usable pages of swap */
244 unsigned int inuse_pages; /* number of those currently in use */
245 unsigned int cluster_next; /* likely index for next allocation */
246 unsigned int cluster_nr; /* countdown to next cluster search */
247 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
248 struct swap_extent *curr_swap_extent;
249 struct swap_extent first_swap_extent;
250 struct block_device *bdev; /* swap device or bdev of swap file */
251 struct file *swap_file; /* seldom referenced */
252 unsigned int old_block_size; /* seldom referenced */
253#ifdef CONFIG_FRONTSWAP
254 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */
255 atomic_t frontswap_pages; /* frontswap pages in-use counter */
256#endif
257 spinlock_t lock; /*
258 * protect map scan related fields like
259 * swap_map, lowest_bit, highest_bit,
260 * inuse_pages, cluster_next,
261 * cluster_nr, lowest_alloc,
262 * highest_alloc, free/discard cluster
263 * list. other fields are only changed
264 * at swapon/swapoff, so are protected
265 * by swap_lock. changing flags need
266 * hold this lock and swap_lock. If
267 * both locks need hold, hold swap_lock
268 * first.
269 */
270 spinlock_t cont_lock; /*
271 * protect swap count continuation page
272 * list.
273 */
274 struct work_struct discard_work; /* discard worker */
275 struct swap_cluster_list discard_clusters; /* discard clusters list */
276};
277
278#ifdef CONFIG_64BIT
279#define SWAP_RA_ORDER_CEILING 5
280#else
281/* Avoid stack overflow, because we need to save part of page table */
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/* linux/mm/workingset.c */
298void *workingset_eviction(struct address_space *mapping, struct page *page);
299bool workingset_refault(void *shadow);
300void workingset_activation(struct page *page);
301
302/* Do not use directly, use workingset_lookup_update */
303void workingset_update_node(struct radix_tree_node *node);
304
305/* Returns workingset_update_node() if the mapping has shadow entries. */
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/* linux/mm/page_alloc.c */
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/* Definition of global_zone_page_state not available yet */
321#define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
322
323
324/* linux/mm/swap.c */
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/* linux/mm/vmscan.c */
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> /* for bio_end_io_t */
384
385/* linux/mm/page_io.c */
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/* linux/mm/swap_state.c */
399/* One swap address space for each 64M swap space */
400#define SWAP_ADDRESS_SPACE_SHIFT 14
401#define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT)
402extern struct address_space *swapper_spaces[];
403extern bool swap_vma_readahead;
404#define swap_address_space(entry) \
405 (&swapper_spaces[swp_type(entry)][swp_offset(entry) \
406 >> SWAP_ADDRESS_SPACE_SHIFT])
407extern unsigned long total_swapcache_pages(void);
408extern void show_swap_cache_info(void);
409extern int add_to_swap(struct page *page);
410extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
411extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
412extern void __delete_from_swap_cache(struct page *);
413extern void delete_from_swap_cache(struct page *);
414extern void free_page_and_swap_cache(struct page *);
415extern void free_pages_and_swap_cache(struct page **, int);
416extern struct page *lookup_swap_cache(swp_entry_t entry,
417 struct vm_area_struct *vma,
418 unsigned long addr);
419extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
420 struct vm_area_struct *vma, unsigned long addr,
421 bool do_poll);
422extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t,
423 struct vm_area_struct *vma, unsigned long addr,
424 bool *new_page_allocated);
425extern struct page *swapin_readahead(swp_entry_t, gfp_t,
426 struct vm_area_struct *vma, unsigned long addr);
427
428extern struct page *swap_readahead_detect(struct vm_fault *vmf,
429 struct vma_swap_readahead *swap_ra);
430extern struct page *do_swap_page_readahead(swp_entry_t fentry, gfp_t gfp_mask,
431 struct vm_fault *vmf,
432 struct vma_swap_readahead *swap_ra);
433
434/* linux/mm/swapfile.c */
435extern atomic_long_t nr_swap_pages;
436extern long total_swap_pages;
437extern atomic_t nr_rotate_swap;
438extern bool has_usable_swap(void);
439
440static inline bool swap_use_vma_readahead(void)
441{
442 return READ_ONCE(swap_vma_readahead) && !atomic_read(&nr_rotate_swap);
443}
444
445/* Swap 50% full? Release swapcache more aggressively.. */
446static inline bool vm_swap_full(void)
447{
448 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
449}
450
451static inline long get_nr_swap_pages(void)
452{
453 return atomic_long_read(&nr_swap_pages);
454}
455
456extern void si_swapinfo(struct sysinfo *);
457extern swp_entry_t get_swap_page(struct page *page);
458extern void put_swap_page(struct page *page, swp_entry_t entry);
459extern swp_entry_t get_swap_page_of_type(int);
460extern int get_swap_pages(int n, bool cluster, swp_entry_t swp_entries[]);
461extern int add_swap_count_continuation(swp_entry_t, gfp_t);
462extern void swap_shmem_alloc(swp_entry_t);
463extern int swap_duplicate(swp_entry_t);
464extern int swapcache_prepare(swp_entry_t);
465extern void swap_free(swp_entry_t);
466extern void swapcache_free_entries(swp_entry_t *entries, int n);
467extern int free_swap_and_cache(swp_entry_t);
468extern int swap_type_of(dev_t, sector_t, struct block_device **);
469extern unsigned int count_swap_pages(int, int);
470extern sector_t map_swap_page(struct page *, struct block_device **);
471extern sector_t swapdev_block(int, pgoff_t);
472extern int page_swapcount(struct page *);
473extern int __swap_count(struct swap_info_struct *si, swp_entry_t entry);
474extern int __swp_swapcount(swp_entry_t entry);
475extern int swp_swapcount(swp_entry_t entry);
476extern struct swap_info_struct *page_swap_info(struct page *);
477extern struct swap_info_struct *swp_swap_info(swp_entry_t entry);
478extern bool reuse_swap_page(struct page *, int *);
479extern int try_to_free_swap(struct page *);
480struct backing_dev_info;
481extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
482extern void exit_swap_address_space(unsigned int type);
483
484#else /* CONFIG_SWAP */
485
486static inline int swap_readpage(struct page *page, bool do_poll)
487{
488 return 0;
489}
490
491static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry)
492{
493 return NULL;
494}
495
496#define swap_address_space(entry) (NULL)
497#define get_nr_swap_pages() 0L
498#define total_swap_pages 0L
499#define total_swapcache_pages() 0UL
500#define vm_swap_full() 0
501
502#define si_swapinfo(val) \
503 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
504/* only sparc can not include linux/pagemap.h in this file
505 * so leave put_page and release_pages undeclared... */
506#define free_page_and_swap_cache(page) \
507 put_page(page)
508#define free_pages_and_swap_cache(pages, nr) \
509 release_pages((pages), (nr));
510
511static inline void show_swap_cache_info(void)
512{
513}
514
515#define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
516#define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
517
518static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
519{
520 return 0;
521}
522
523static inline void swap_shmem_alloc(swp_entry_t swp)
524{
525}
526
527static inline int swap_duplicate(swp_entry_t swp)
528{
529 return 0;
530}
531
532static inline void swap_free(swp_entry_t swp)
533{
534}
535
536static inline void put_swap_page(struct page *page, swp_entry_t swp)
537{
538}
539
540static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
541 struct vm_area_struct *vma, unsigned long addr)
542{
543 return NULL;
544}
545
546static inline bool swap_use_vma_readahead(void)
547{
548 return false;
549}
550
551static inline struct page *swap_readahead_detect(
552 struct vm_fault *vmf, struct vma_swap_readahead *swap_ra)
553{
554 return NULL;
555}
556
557static inline struct page *do_swap_page_readahead(
558 swp_entry_t fentry, gfp_t gfp_mask,
559 struct vm_fault *vmf, struct vma_swap_readahead *swap_ra)
560{
561 return NULL;
562}
563
564static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
565{
566 return 0;
567}
568
569static inline struct page *lookup_swap_cache(swp_entry_t swp,
570 struct vm_area_struct *vma,
571 unsigned long addr)
572{
573 return NULL;
574}
575
576static inline int add_to_swap(struct page *page)
577{
578 return 0;
579}
580
581static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
582 gfp_t gfp_mask)
583{
584 return -1;
585}
586
587static inline void __delete_from_swap_cache(struct page *page)
588{
589}
590
591static inline void delete_from_swap_cache(struct page *page)
592{
593}
594
595static inline int page_swapcount(struct page *page)
596{
597 return 0;
598}
599
600static inline int __swap_count(struct swap_info_struct *si, swp_entry_t entry)
601{
602 return 0;
603}
604
605static inline int __swp_swapcount(swp_entry_t entry)
606{
607 return 0;
608}
609
610static inline int swp_swapcount(swp_entry_t entry)
611{
612 return 0;
613}
614
615#define reuse_swap_page(page, total_map_swapcount) \
616 (page_trans_huge_mapcount(page, total_map_swapcount) == 1)
617
618static inline int try_to_free_swap(struct page *page)
619{
620 return 0;
621}
622
623static inline swp_entry_t get_swap_page(struct page *page)
624{
625 swp_entry_t entry;
626 entry.val = 0;
627 return entry;
628}
629
630#endif /* CONFIG_SWAP */
631
632#ifdef CONFIG_THP_SWAP
633extern int split_swap_cluster(swp_entry_t entry);
634#else
635static inline int split_swap_cluster(swp_entry_t entry)
636{
637 return 0;
638}
639#endif
640
641#ifdef CONFIG_MEMCG
642static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
643{
644 /* Cgroup2 doesn't have per-cgroup swappiness */
645 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
646 return vm_swappiness;
647
648 /* root ? */
649 if (mem_cgroup_disabled() || !memcg->css.parent)
650 return vm_swappiness;
651
652 return memcg->swappiness;
653}
654
655#else
656static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
657{
658 return vm_swappiness;
659}
660#endif
661
662#ifdef CONFIG_MEMCG_SWAP
663extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);
664extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);
665extern void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
666extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
667extern bool mem_cgroup_swap_full(struct page *page);
668#else
669static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
670{
671}
672
673static inline int mem_cgroup_try_charge_swap(struct page *page,
674 swp_entry_t entry)
675{
676 return 0;
677}
678
679static inline void mem_cgroup_uncharge_swap(swp_entry_t entry,
680 unsigned int nr_pages)
681{
682}
683
684static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
685{
686 return get_nr_swap_pages();
687}
688
689static inline bool mem_cgroup_swap_full(struct page *page)
690{
691 return vm_swap_full();
692}
693#endif
694
695#endif /* __KERNEL__*/
696#endif /* _LINUX_SWAP_H */