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#define SWP_SWAPIN_ERROR_NUM 1
59#define SWP_SWAPIN_ERROR (MAX_SWAPFILES + SWP_HWPOISON_NUM + \
60 SWP_MIGRATION_NUM + SWP_DEVICE_NUM + \
61 SWP_PTE_MARKER_NUM)
62/*
63 * PTE markers are used to persist information onto PTEs that are mapped with
64 * file-backed memories. As its name "PTE" hints, it should only be applied to
65 * the leaves of pgtables.
66 */
67#ifdef CONFIG_PTE_MARKER
68#define SWP_PTE_MARKER_NUM 1
69#define SWP_PTE_MARKER (MAX_SWAPFILES + SWP_HWPOISON_NUM + \
70 SWP_MIGRATION_NUM + SWP_DEVICE_NUM)
71#else
72#define SWP_PTE_MARKER_NUM 0
73#endif
74
75/*
76 * Unaddressable device memory support. See include/linux/hmm.h and
77 * Documentation/mm/hmm.rst. Short description is we need struct pages for
78 * device memory that is unaddressable (inaccessible) by CPU, so that we can
79 * migrate part of a process memory to device memory.
80 *
81 * When a page is migrated from CPU to device, we set the CPU page table entry
82 * to a special SWP_DEVICE_{READ|WRITE} entry.
83 *
84 * When a page is mapped by the device for exclusive access we set the CPU page
85 * table entries to special SWP_DEVICE_EXCLUSIVE_* entries.
86 */
87#ifdef CONFIG_DEVICE_PRIVATE
88#define SWP_DEVICE_NUM 4
89#define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM)
90#define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1)
91#define SWP_DEVICE_EXCLUSIVE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2)
92#define SWP_DEVICE_EXCLUSIVE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+3)
93#else
94#define SWP_DEVICE_NUM 0
95#endif
96
97/*
98 * Page migration support.
99 *
100 * SWP_MIGRATION_READ_EXCLUSIVE is only applicable to anonymous pages and
101 * indicates that the referenced (part of) an anonymous page is exclusive to
102 * a single process. For SWP_MIGRATION_WRITE, that information is implicit:
103 * (part of) an anonymous page that are mapped writable are exclusive to a
104 * single process.
105 */
106#ifdef CONFIG_MIGRATION
107#define SWP_MIGRATION_NUM 3
108#define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
109#define SWP_MIGRATION_READ_EXCLUSIVE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
110#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 2)
111#else
112#define SWP_MIGRATION_NUM 0
113#endif
114
115/*
116 * Handling of hardware poisoned pages with memory corruption.
117 */
118#ifdef CONFIG_MEMORY_FAILURE
119#define SWP_HWPOISON_NUM 1
120#define SWP_HWPOISON MAX_SWAPFILES
121#else
122#define SWP_HWPOISON_NUM 0
123#endif
124
125#define MAX_SWAPFILES \
126 ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \
127 SWP_MIGRATION_NUM - SWP_HWPOISON_NUM - \
128 SWP_PTE_MARKER_NUM - SWP_SWAPIN_ERROR_NUM)
129
130/*
131 * Magic header for a swap area. The first part of the union is
132 * what the swap magic looks like for the old (limited to 128MB)
133 * swap area format, the second part of the union adds - in the
134 * old reserved area - some extra information. Note that the first
135 * kilobyte is reserved for boot loader or disk label stuff...
136 *
137 * Having the magic at the end of the PAGE_SIZE makes detecting swap
138 * areas somewhat tricky on machines that support multiple page sizes.
139 * For 2.5 we'll probably want to move the magic to just beyond the
140 * bootbits...
141 */
142union swap_header {
143 struct {
144 char reserved[PAGE_SIZE - 10];
145 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
146 } magic;
147 struct {
148 char bootbits[1024]; /* Space for disklabel etc. */
149 __u32 version;
150 __u32 last_page;
151 __u32 nr_badpages;
152 unsigned char sws_uuid[16];
153 unsigned char sws_volume[16];
154 __u32 padding[117];
155 __u32 badpages[1];
156 } info;
157};
158
159/*
160 * current->reclaim_state points to one of these when a task is running
161 * memory reclaim
162 */
163struct reclaim_state {
164 unsigned long reclaimed_slab;
165};
166
167#ifdef __KERNEL__
168
169struct address_space;
170struct sysinfo;
171struct writeback_control;
172struct zone;
173
174/*
175 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
176 * disk blocks. A rbtree of swap extents maps the entire swapfile (Where the
177 * term `swapfile' refers to either a blockdevice or an IS_REG file). Apart
178 * from setup, they're handled identically.
179 *
180 * We always assume that blocks are of size PAGE_SIZE.
181 */
182struct swap_extent {
183 struct rb_node rb_node;
184 pgoff_t start_page;
185 pgoff_t nr_pages;
186 sector_t start_block;
187};
188
189/*
190 * Max bad pages in the new format..
191 */
192#define MAX_SWAP_BADPAGES \
193 ((offsetof(union swap_header, magic.magic) - \
194 offsetof(union swap_header, info.badpages)) / sizeof(int))
195
196enum {
197 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
198 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
199 SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */
200 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
201 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
202 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
203 SWP_BLKDEV = (1 << 6), /* its a block device */
204 SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */
205 SWP_FS_OPS = (1 << 8), /* swapfile operations go through fs */
206 SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */
207 SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */
208 SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */
209 SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */
210 /* add others here before... */
211 SWP_SCANNING = (1 << 14), /* refcount in scan_swap_map */
212};
213
214#define SWAP_CLUSTER_MAX 32UL
215#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
216
217/* Bit flag in swap_map */
218#define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
219#define COUNT_CONTINUED 0x80 /* Flag swap_map continuation for full count */
220
221/* Special value in first swap_map */
222#define SWAP_MAP_MAX 0x3e /* Max count */
223#define SWAP_MAP_BAD 0x3f /* Note page is bad */
224#define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs */
225
226/* Special value in each swap_map continuation */
227#define SWAP_CONT_MAX 0x7f /* Max count */
228
229/*
230 * We use this to track usage of a cluster. A cluster is a block of swap disk
231 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All
232 * free clusters are organized into a list. We fetch an entry from the list to
233 * get a free cluster.
234 *
235 * The data field stores next cluster if the cluster is free or cluster usage
236 * counter otherwise. The flags field determines if a cluster is free. This is
237 * protected by swap_info_struct.lock.
238 */
239struct swap_cluster_info {
240 spinlock_t lock; /*
241 * Protect swap_cluster_info fields
242 * and swap_info_struct->swap_map
243 * elements correspond to the swap
244 * cluster
245 */
246 unsigned int data:24;
247 unsigned int flags:8;
248};
249#define CLUSTER_FLAG_FREE 1 /* This cluster is free */
250#define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */
251#define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */
252
253/*
254 * We assign a cluster to each CPU, so each CPU can allocate swap entry from
255 * its own cluster and swapout sequentially. The purpose is to optimize swapout
256 * throughput.
257 */
258struct percpu_cluster {
259 struct swap_cluster_info index; /* Current cluster index */
260 unsigned int next; /* Likely next allocation offset */
261};
262
263struct swap_cluster_list {
264 struct swap_cluster_info head;
265 struct swap_cluster_info tail;
266};
267
268/*
269 * The in-memory structure used to track swap areas.
270 */
271struct swap_info_struct {
272 struct percpu_ref users; /* indicate and keep swap device valid. */
273 unsigned long flags; /* SWP_USED etc: see above */
274 signed short prio; /* swap priority of this type */
275 struct plist_node list; /* entry in swap_active_head */
276 signed char type; /* strange name for an index */
277 unsigned int max; /* extent of the swap_map */
278 unsigned char *swap_map; /* vmalloc'ed array of usage counts */
279 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
280 struct swap_cluster_list free_clusters; /* free clusters list */
281 unsigned int lowest_bit; /* index of first free in swap_map */
282 unsigned int highest_bit; /* index of last free in swap_map */
283 unsigned int pages; /* total of usable pages of swap */
284 unsigned int inuse_pages; /* number of those currently in use */
285 unsigned int cluster_next; /* likely index for next allocation */
286 unsigned int cluster_nr; /* countdown to next cluster search */
287 unsigned int __percpu *cluster_next_cpu; /*percpu index for next allocation */
288 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
289 struct rb_root swap_extent_root;/* root of the swap extent rbtree */
290 struct block_device *bdev; /* swap device or bdev of swap file */
291 struct file *swap_file; /* seldom referenced */
292 unsigned int old_block_size; /* seldom referenced */
293 struct completion comp; /* seldom referenced */
294#ifdef CONFIG_FRONTSWAP
295 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */
296 atomic_t frontswap_pages; /* frontswap pages in-use counter */
297#endif
298 spinlock_t lock; /*
299 * protect map scan related fields like
300 * swap_map, lowest_bit, highest_bit,
301 * inuse_pages, cluster_next,
302 * cluster_nr, lowest_alloc,
303 * highest_alloc, free/discard cluster
304 * list. other fields are only changed
305 * at swapon/swapoff, so are protected
306 * by swap_lock. changing flags need
307 * hold this lock and swap_lock. If
308 * both locks need hold, hold swap_lock
309 * first.
310 */
311 spinlock_t cont_lock; /*
312 * protect swap count continuation page
313 * list.
314 */
315 struct work_struct discard_work; /* discard worker */
316 struct swap_cluster_list discard_clusters; /* discard clusters list */
317 struct plist_node avail_lists[]; /*
318 * entries in swap_avail_heads, one
319 * entry per node.
320 * Must be last as the number of the
321 * array is nr_node_ids, which is not
322 * a fixed value so have to allocate
323 * dynamically.
324 * And it has to be an array so that
325 * plist_for_each_* can work.
326 */
327};
328
329#ifdef CONFIG_64BIT
330#define SWAP_RA_ORDER_CEILING 5
331#else
332/* Avoid stack overflow, because we need to save part of page table */
333#define SWAP_RA_ORDER_CEILING 3
334#define SWAP_RA_PTE_CACHE_SIZE (1 << SWAP_RA_ORDER_CEILING)
335#endif
336
337struct vma_swap_readahead {
338 unsigned short win;
339 unsigned short offset;
340 unsigned short nr_pte;
341#ifdef CONFIG_64BIT
342 pte_t *ptes;
343#else
344 pte_t ptes[SWAP_RA_PTE_CACHE_SIZE];
345#endif
346};
347
348static inline swp_entry_t folio_swap_entry(struct folio *folio)
349{
350 swp_entry_t entry = { .val = page_private(&folio->page) };
351 return entry;
352}
353
354/* linux/mm/workingset.c */
355void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages);
356void *workingset_eviction(struct folio *folio, struct mem_cgroup *target_memcg);
357void workingset_refault(struct folio *folio, void *shadow);
358void workingset_activation(struct folio *folio);
359
360/* Only track the nodes of mappings with shadow entries */
361void workingset_update_node(struct xa_node *node);
362extern struct list_lru shadow_nodes;
363#define mapping_set_update(xas, mapping) do { \
364 if (!dax_mapping(mapping) && !shmem_mapping(mapping)) { \
365 xas_set_update(xas, workingset_update_node); \
366 xas_set_lru(xas, &shadow_nodes); \
367 } \
368} while (0)
369
370/* linux/mm/page_alloc.c */
371extern unsigned long totalreserve_pages;
372
373/* Definition of global_zone_page_state not available yet */
374#define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
375
376
377/* linux/mm/swap.c */
378extern void lru_note_cost(struct lruvec *lruvec, bool file,
379 unsigned int nr_pages);
380extern void lru_note_cost_folio(struct folio *);
381extern void folio_add_lru(struct folio *);
382extern void lru_cache_add(struct page *);
383void mark_page_accessed(struct page *);
384void folio_mark_accessed(struct folio *);
385
386extern atomic_t lru_disable_count;
387
388static inline bool lru_cache_disabled(void)
389{
390 return atomic_read(&lru_disable_count);
391}
392
393static inline void lru_cache_enable(void)
394{
395 atomic_dec(&lru_disable_count);
396}
397
398extern void lru_cache_disable(void);
399extern void lru_add_drain(void);
400extern void lru_add_drain_cpu(int cpu);
401extern void lru_add_drain_cpu_zone(struct zone *zone);
402extern void lru_add_drain_all(void);
403extern void deactivate_page(struct page *page);
404extern void mark_page_lazyfree(struct page *page);
405extern void swap_setup(void);
406
407extern void lru_cache_add_inactive_or_unevictable(struct page *page,
408 struct vm_area_struct *vma);
409
410/* linux/mm/vmscan.c */
411extern unsigned long zone_reclaimable_pages(struct zone *zone);
412extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
413 gfp_t gfp_mask, nodemask_t *mask);
414
415#define MEMCG_RECLAIM_MAY_SWAP (1 << 1)
416#define MEMCG_RECLAIM_PROACTIVE (1 << 2)
417extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
418 unsigned long nr_pages,
419 gfp_t gfp_mask,
420 unsigned int reclaim_options);
421extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
422 gfp_t gfp_mask, bool noswap,
423 pg_data_t *pgdat,
424 unsigned long *nr_scanned);
425extern unsigned long shrink_all_memory(unsigned long nr_pages);
426extern int vm_swappiness;
427long remove_mapping(struct address_space *mapping, struct folio *folio);
428
429extern unsigned long reclaim_pages(struct list_head *page_list);
430#ifdef CONFIG_NUMA
431extern int node_reclaim_mode;
432extern int sysctl_min_unmapped_ratio;
433extern int sysctl_min_slab_ratio;
434#else
435#define node_reclaim_mode 0
436#endif
437
438static inline bool node_reclaim_enabled(void)
439{
440 /* Is any node_reclaim_mode bit set? */
441 return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP);
442}
443
444void check_move_unevictable_folios(struct folio_batch *fbatch);
445void check_move_unevictable_pages(struct pagevec *pvec);
446
447extern void kswapd_run(int nid);
448extern void kswapd_stop(int nid);
449
450#ifdef CONFIG_SWAP
451
452int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
453 unsigned long nr_pages, sector_t start_block);
454int generic_swapfile_activate(struct swap_info_struct *, struct file *,
455 sector_t *);
456
457static inline unsigned long total_swapcache_pages(void)
458{
459 return global_node_page_state(NR_SWAPCACHE);
460}
461
462extern void free_swap_cache(struct page *page);
463extern void free_page_and_swap_cache(struct page *);
464extern void free_pages_and_swap_cache(struct page **, int);
465/* linux/mm/swapfile.c */
466extern atomic_long_t nr_swap_pages;
467extern long total_swap_pages;
468extern atomic_t nr_rotate_swap;
469extern bool has_usable_swap(void);
470
471/* Swap 50% full? Release swapcache more aggressively.. */
472static inline bool vm_swap_full(void)
473{
474 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
475}
476
477static inline long get_nr_swap_pages(void)
478{
479 return atomic_long_read(&nr_swap_pages);
480}
481
482extern void si_swapinfo(struct sysinfo *);
483swp_entry_t folio_alloc_swap(struct folio *folio);
484extern void put_swap_page(struct page *page, swp_entry_t entry);
485extern swp_entry_t get_swap_page_of_type(int);
486extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size);
487extern int add_swap_count_continuation(swp_entry_t, gfp_t);
488extern void swap_shmem_alloc(swp_entry_t);
489extern int swap_duplicate(swp_entry_t);
490extern int swapcache_prepare(swp_entry_t);
491extern void swap_free(swp_entry_t);
492extern void swapcache_free_entries(swp_entry_t *entries, int n);
493extern int free_swap_and_cache(swp_entry_t);
494int swap_type_of(dev_t device, sector_t offset);
495int find_first_swap(dev_t *device);
496extern unsigned int count_swap_pages(int, int);
497extern sector_t swapdev_block(int, pgoff_t);
498extern int __swap_count(swp_entry_t entry);
499extern int __swp_swapcount(swp_entry_t entry);
500extern int swp_swapcount(swp_entry_t entry);
501extern struct swap_info_struct *page_swap_info(struct page *);
502extern struct swap_info_struct *swp_swap_info(swp_entry_t entry);
503extern int try_to_free_swap(struct page *);
504struct backing_dev_info;
505extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
506extern void exit_swap_address_space(unsigned int type);
507extern struct swap_info_struct *get_swap_device(swp_entry_t entry);
508sector_t swap_page_sector(struct page *page);
509
510static inline void put_swap_device(struct swap_info_struct *si)
511{
512 percpu_ref_put(&si->users);
513}
514
515#else /* CONFIG_SWAP */
516static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry)
517{
518 return NULL;
519}
520
521static inline struct swap_info_struct *get_swap_device(swp_entry_t entry)
522{
523 return NULL;
524}
525
526static inline void put_swap_device(struct swap_info_struct *si)
527{
528}
529
530#define get_nr_swap_pages() 0L
531#define total_swap_pages 0L
532#define total_swapcache_pages() 0UL
533#define vm_swap_full() 0
534
535#define si_swapinfo(val) \
536 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
537/* only sparc can not include linux/pagemap.h in this file
538 * so leave put_page and release_pages undeclared... */
539#define free_page_and_swap_cache(page) \
540 put_page(page)
541#define free_pages_and_swap_cache(pages, nr) \
542 release_pages((pages), (nr));
543
544/* used to sanity check ptes in zap_pte_range when CONFIG_SWAP=0 */
545#define free_swap_and_cache(e) is_pfn_swap_entry(e)
546
547static inline void free_swap_cache(struct page *page)
548{
549}
550
551static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
552{
553 return 0;
554}
555
556static inline void swap_shmem_alloc(swp_entry_t swp)
557{
558}
559
560static inline int swap_duplicate(swp_entry_t swp)
561{
562 return 0;
563}
564
565static inline void swap_free(swp_entry_t swp)
566{
567}
568
569static inline void put_swap_page(struct page *page, swp_entry_t swp)
570{
571}
572
573static inline int __swap_count(swp_entry_t entry)
574{
575 return 0;
576}
577
578static inline int __swp_swapcount(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 try_to_free_swap(struct page *page)
589{
590 return 0;
591}
592
593static inline swp_entry_t folio_alloc_swap(struct folio *folio)
594{
595 swp_entry_t entry;
596 entry.val = 0;
597 return entry;
598}
599
600static inline int add_swap_extent(struct swap_info_struct *sis,
601 unsigned long start_page,
602 unsigned long nr_pages, sector_t start_block)
603{
604 return -EINVAL;
605}
606#endif /* CONFIG_SWAP */
607
608#ifdef CONFIG_THP_SWAP
609extern int split_swap_cluster(swp_entry_t entry);
610#else
611static inline int split_swap_cluster(swp_entry_t entry)
612{
613 return 0;
614}
615#endif
616
617#ifdef CONFIG_MEMCG
618static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
619{
620 /* Cgroup2 doesn't have per-cgroup swappiness */
621 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
622 return vm_swappiness;
623
624 /* root ? */
625 if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg))
626 return vm_swappiness;
627
628 return memcg->swappiness;
629}
630#else
631static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
632{
633 return vm_swappiness;
634}
635#endif
636
637#ifdef CONFIG_ZSWAP
638extern u64 zswap_pool_total_size;
639extern atomic_t zswap_stored_pages;
640#endif
641
642#if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
643extern void __cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask);
644static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
645{
646 if (mem_cgroup_disabled())
647 return;
648 __cgroup_throttle_swaprate(page, gfp_mask);
649}
650#else
651static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
652{
653}
654#endif
655static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp)
656{
657 cgroup_throttle_swaprate(&folio->page, gfp);
658}
659
660#ifdef CONFIG_MEMCG_SWAP
661void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry);
662int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry);
663static inline int mem_cgroup_try_charge_swap(struct folio *folio,
664 swp_entry_t entry)
665{
666 if (mem_cgroup_disabled())
667 return 0;
668 return __mem_cgroup_try_charge_swap(folio, entry);
669}
670
671extern void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
672static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
673{
674 if (mem_cgroup_disabled())
675 return;
676 __mem_cgroup_uncharge_swap(entry, nr_pages);
677}
678
679extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
680extern bool mem_cgroup_swap_full(struct page *page);
681#else
682static inline void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry)
683{
684}
685
686static inline int mem_cgroup_try_charge_swap(struct folio *folio,
687 swp_entry_t entry)
688{
689 return 0;
690}
691
692static inline void mem_cgroup_uncharge_swap(swp_entry_t entry,
693 unsigned int nr_pages)
694{
695}
696
697static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
698{
699 return get_nr_swap_pages();
700}
701
702static inline bool mem_cgroup_swap_full(struct page *page)
703{
704 return vm_swap_full();
705}
706#endif
707
708#endif /* __KERNEL__*/
709#endif /* _LINUX_SWAP_H */
710

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