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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
21struct pagevec;
22
23#define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
24#define SWAP_FLAG_PRIO_MASK 0x7fff
25#define SWAP_FLAG_PRIO_SHIFT 0
26#define SWAP_FLAG_DISCARD 0x10000 /* enable discard for swap */
27#define SWAP_FLAG_DISCARD_ONCE 0x20000 /* discard swap area at swapon-time */
28#define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */
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 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
42 * be swapped to. The swap type and the offset into that swap type are
43 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits
44 * for the type means that the maximum number of swapcache pages is 27 bits
45 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
46 * the type/offset into the pte as 5/27 as well.
47 */
48#define MAX_SWAPFILES_SHIFT 5
49
50/*
51 * Use some of the swap files numbers for other purposes. This
52 * is a convenient way to hook into the VM to trigger special
53 * actions on faults.
54 */
55
56/*
57 * Unaddressable device memory support. See include/linux/hmm.h and
58 * Documentation/vm/hmm.rst. Short description is we need struct pages for
59 * device memory that is unaddressable (inaccessible) by CPU, so that we can
60 * migrate part of a process memory to device memory.
61 *
62 * When a page is migrated from CPU to device, we set the CPU page table entry
63 * to a special SWP_DEVICE_* entry.
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 * NUMA node memory migration support
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 * Handling of hardware poisoned pages with memory corruption.
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 * Magic header for a swap area. The first part of the union is
100 * what the swap magic looks like for the old (limited to 128MB)
101 * swap area format, the second part of the union adds - in the
102 * old reserved area - some extra information. Note that the first
103 * kilobyte is reserved for boot loader or disk label stuff...
104 *
105 * Having the magic at the end of the PAGE_SIZE makes detecting swap
106 * areas somewhat tricky on machines that support multiple page sizes.
107 * For 2.5 we'll probably want to move the magic to just beyond the
108 * bootbits...
109 */
110union swap_header {
111 struct {
112 char reserved[PAGE_SIZE - 10];
113 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
114 } magic;
115 struct {
116 char bootbits[1024]; /* Space for disklabel etc. */
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 * current->reclaim_state points to one of these when a task is running
129 * memory reclaim
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 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
144 * disk blocks. A list of swap extents maps the entire swapfile. (Where the
145 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
146 * from setup, they're handled identically.
147 *
148 * We always assume that blocks are of size PAGE_SIZE.
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 * Max bad pages in the new format..
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), /* is slot in swap_info[] used? */
166 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
167 SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */
168 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
169 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
170 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
171 SWP_BLKDEV = (1 << 6), /* its a block device */
172 SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */
173 SWP_FS = (1 << 8), /* swap file goes through fs */
174 SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */
175 SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */
176 SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */
177 SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */
178 SWP_VALID = (1 << 13), /* swap is valid to be operated on? */
179 /* add others here before... */
180 SWP_SCANNING = (1 << 14), /* refcount in scan_swap_map */
181};
182
183#define SWAP_CLUSTER_MAX 32UL
184#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
185
186#define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */
187#define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */
188#define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
189#define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */
190#define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */
191#define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */
192
193/*
194 * We use this to track usage of a cluster. A cluster is a block of swap disk
195 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All
196 * free clusters are organized into a list. We fetch an entry from the list to
197 * get a free cluster.
198 *
199 * The data field stores next cluster if the cluster is free or cluster usage
200 * counter otherwise. The flags field determines if a cluster is free. This is
201 * protected by swap_info_struct.lock.
202 */
203struct swap_cluster_info {
204 spinlock_t lock; /*
205 * Protect swap_cluster_info fields
206 * and swap_info_struct->swap_map
207 * elements correspond to the swap
208 * cluster
209 */
210 unsigned int data:24;
211 unsigned int flags:8;
212};
213#define CLUSTER_FLAG_FREE 1 /* This cluster is free */
214#define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */
215#define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */
216
217/*
218 * We assign a cluster to each CPU, so each CPU can allocate swap entry from
219 * its own cluster and swapout sequentially. The purpose is to optimize swapout
220 * throughput.
221 */
222struct percpu_cluster {
223 struct swap_cluster_info index; /* Current cluster index */
224 unsigned int next; /* Likely next allocation offset */
225};
226
227struct swap_cluster_list {
228 struct swap_cluster_info head;
229 struct swap_cluster_info tail;
230};
231
232/*
233 * The in-memory structure used to track swap areas.
234 */
235struct swap_info_struct {
236 unsigned long flags; /* SWP_USED etc: see above */
237 signed short prio; /* swap priority of this type */
238 struct plist_node list; /* entry in swap_active_head */
239 signed char type; /* strange name for an index */
240 unsigned int max; /* extent of the swap_map */
241 unsigned char *swap_map; /* vmalloc'ed array of usage counts */
242 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
243 struct swap_cluster_list free_clusters; /* free clusters list */
244 unsigned int lowest_bit; /* index of first free in swap_map */
245 unsigned int highest_bit; /* index of last free in swap_map */
246 unsigned int pages; /* total of usable pages of swap */
247 unsigned int inuse_pages; /* number of those currently in use */
248 unsigned int cluster_next; /* likely index for next allocation */
249 unsigned int cluster_nr; /* countdown to next cluster search */
250 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
251 struct rb_root swap_extent_root;/* root of the swap extent rbtree */
252 struct block_device *bdev; /* swap device or bdev of swap file */
253 struct file *swap_file; /* seldom referenced */
254 unsigned int old_block_size; /* seldom referenced */
255#ifdef CONFIG_FRONTSWAP
256 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */
257 atomic_t frontswap_pages; /* frontswap pages in-use counter */
258#endif
259 spinlock_t lock; /*
260 * protect map scan related fields like
261 * swap_map, lowest_bit, highest_bit,
262 * inuse_pages, cluster_next,
263 * cluster_nr, lowest_alloc,
264 * highest_alloc, free/discard cluster
265 * list. other fields are only changed
266 * at swapon/swapoff, so are protected
267 * by swap_lock. changing flags need
268 * hold this lock and swap_lock. If
269 * both locks need hold, hold swap_lock
270 * first.
271 */
272 spinlock_t cont_lock; /*
273 * protect swap count continuation page
274 * list.
275 */
276 struct work_struct discard_work; /* discard worker */
277 struct swap_cluster_list discard_clusters; /* discard clusters list */
278 struct plist_node avail_lists[0]; /*
279 * entries in swap_avail_heads, one
280 * entry per node.
281 * Must be last as the number of the
282 * array is nr_node_ids, which is not
283 * a fixed value so have to allocate
284 * dynamically.
285 * And it has to be an array so that
286 * plist_for_each_* can work.
287 */
288};
289
290#ifdef CONFIG_64BIT
291#define SWAP_RA_ORDER_CEILING 5
292#else
293/* Avoid stack overflow, because we need to save part of page table */
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/* linux/mm/workingset.c */
310void *workingset_eviction(struct page *page);
311void workingset_refault(struct page *page, void *shadow);
312void workingset_activation(struct page *page);
313
314/* Only track the nodes of mappings with shadow entries */
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/* linux/mm/page_alloc.c */
322extern unsigned long totalreserve_pages;
323extern unsigned long nr_free_buffer_pages(void);
324extern unsigned long nr_free_pagecache_pages(void);
325
326/* Definition of global_zone_page_state not available yet */
327#define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
328
329
330/* linux/mm/swap.c */
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 mark_page_lazyfree(struct page *page);
344extern void swap_setup(void);
345
346extern void lru_cache_add_active_or_unevictable(struct page *page,
347 struct vm_area_struct *vma);
348
349/* linux/mm/vmscan.c */
350extern unsigned long zone_reclaimable_pages(struct zone *zone);
351extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
352 gfp_t gfp_mask, nodemask_t *mask);
353extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
354extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
355 unsigned long nr_pages,
356 gfp_t gfp_mask,
357 bool may_swap);
358extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
359 gfp_t gfp_mask, bool noswap,
360 pg_data_t *pgdat,
361 unsigned long *nr_scanned);
362extern unsigned long shrink_all_memory(unsigned long nr_pages);
363extern int vm_swappiness;
364extern int remove_mapping(struct address_space *mapping, struct page *page);
365extern unsigned long vm_total_pages;
366
367#ifdef CONFIG_NUMA
368extern int node_reclaim_mode;
369extern int sysctl_min_unmapped_ratio;
370extern int sysctl_min_slab_ratio;
371#else
372#define node_reclaim_mode 0
373#endif
374
375extern int page_evictable(struct page *page);
376extern void check_move_unevictable_pages(struct pagevec *pvec);
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[];
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 *, swp_entry_t entry);
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/* linux/mm/swapfile.c */
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/* Swap 50% full? Release swapcache more aggressively.. */
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, swp_entry_t swp_entries[], int entry_size);
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(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);
473extern struct swap_info_struct *get_swap_device(swp_entry_t entry);
474
475static inline void put_swap_device(struct swap_info_struct *si)
476{
477 rcu_read_unlock();
478}
479
480#else /* CONFIG_SWAP */
481
482static inline int swap_readpage(struct page *page, bool do_poll)
483{
484 return 0;
485}
486
487static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry)
488{
489 return NULL;
490}
491
492#define swap_address_space(entry) (NULL)
493#define get_nr_swap_pages() 0L
494#define total_swap_pages 0L
495#define total_swapcache_pages() 0UL
496#define vm_swap_full() 0
497
498#define si_swapinfo(val) \
499 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
500/* only sparc can not include linux/pagemap.h in this file
501 * so leave put_page and release_pages undeclared... */
502#define free_page_and_swap_cache(page) \
503 put_page(page)
504#define free_pages_and_swap_cache(pages, nr) \
505 release_pages((pages), (nr));
506
507static inline void show_swap_cache_info(void)
508{
509}
510
511#define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
512#define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
513
514static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
515{
516 return 0;
517}
518
519static inline void swap_shmem_alloc(swp_entry_t swp)
520{
521}
522
523static inline int swap_duplicate(swp_entry_t swp)
524{
525 return 0;
526}
527
528static inline void swap_free(swp_entry_t swp)
529{
530}
531
532static inline void put_swap_page(struct page *page, swp_entry_t swp)
533{
534}
535
536static inline struct page *swap_cluster_readahead(swp_entry_t entry,
537 gfp_t gfp_mask, struct vm_fault *vmf)
538{
539 return NULL;
540}
541
542static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
543 struct vm_fault *vmf)
544{
545 return NULL;
546}
547
548static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
549{
550 return 0;
551}
552
553static inline struct page *lookup_swap_cache(swp_entry_t swp,
554 struct vm_area_struct *vma,
555 unsigned long addr)
556{
557 return NULL;
558}
559
560static inline int add_to_swap(struct page *page)
561{
562 return 0;
563}
564
565static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
566 gfp_t gfp_mask)
567{
568 return -1;
569}
570
571static inline void __delete_from_swap_cache(struct page *page,
572 swp_entry_t entry)
573{
574}
575
576static inline void delete_from_swap_cache(struct page *page)
577{
578}
579
580static inline int page_swapcount(struct page *page)
581{
582 return 0;
583}
584
585static inline int __swap_count(swp_entry_t entry)
586{
587 return 0;
588}
589
590static inline int __swp_swapcount(swp_entry_t entry)
591{
592 return 0;
593}
594
595static inline int swp_swapcount(swp_entry_t entry)
596{
597 return 0;
598}
599
600#define reuse_swap_page(page, total_map_swapcount) \
601 (page_trans_huge_mapcount(page, total_map_swapcount) == 1)
602
603static inline int try_to_free_swap(struct page *page)
604{
605 return 0;
606}
607
608static inline swp_entry_t get_swap_page(struct page *page)
609{
610 swp_entry_t entry;
611 entry.val = 0;
612 return entry;
613}
614
615#endif /* CONFIG_SWAP */
616
617#ifdef CONFIG_THP_SWAP
618extern int split_swap_cluster(swp_entry_t entry);
619#else
620static inline int split_swap_cluster(swp_entry_t entry)
621{
622 return 0;
623}
624#endif
625
626#ifdef CONFIG_MEMCG
627static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
628{
629 /* Cgroup2 doesn't have per-cgroup swappiness */
630 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
631 return vm_swappiness;
632
633 /* root ? */
634 if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg))
635 return vm_swappiness;
636
637 return memcg->swappiness;
638}
639#else
640static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
641{
642 return vm_swappiness;
643}
644#endif
645
646#if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
647extern void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg, int node,
648 gfp_t gfp_mask);
649#else
650static inline void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg,
651 int node, gfp_t gfp_mask)
652{
653}
654#endif
655
656#ifdef CONFIG_MEMCG_SWAP
657extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);
658extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);
659extern void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
660extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
661extern bool mem_cgroup_swap_full(struct page *page);
662#else
663static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
664{
665}
666
667static inline int mem_cgroup_try_charge_swap(struct page *page,
668 swp_entry_t entry)
669{
670 return 0;
671}
672
673static inline void mem_cgroup_uncharge_swap(swp_entry_t entry,
674 unsigned int nr_pages)
675{
676}
677
678static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
679{
680 return get_nr_swap_pages();
681}
682
683static inline bool mem_cgroup_swap_full(struct page *page)
684{
685 return vm_swap_full();
686}
687#endif
688
689#endif /* __KERNEL__*/
690#endif /* _LINUX_SWAP_H */