Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_SWAP_H
3#define _LINUX_SWAP_H
4
5#include <linux/spinlock.h>
6#include <linux/linkage.h>
7#include <linux/mmzone.h>
8#include <linux/list.h>
9#include <linux/memcontrol.h>
10#include <linux/sched.h>
11#include <linux/node.h>
12#include <linux/fs.h>
13#include <linux/pagemap.h>
14#include <linux/atomic.h>
15#include <linux/page-flags.h>
16#include <uapi/linux/mempolicy.h>
17#include <asm/page.h>
18
19struct notifier_block;
20
21struct bio;
22
23struct pagevec;
24
25#define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
26#define SWAP_FLAG_PRIO_MASK 0x7fff
27#define SWAP_FLAG_PRIO_SHIFT 0
28#define SWAP_FLAG_DISCARD 0x10000 /* enable discard for swap */
29#define SWAP_FLAG_DISCARD_ONCE 0x20000 /* discard swap area at swapon-time */
30#define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */
31
32#define SWAP_FLAGS_VALID (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \
33 SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \
34 SWAP_FLAG_DISCARD_PAGES)
35#define SWAP_BATCH 64
36
37static inline int current_is_kswapd(void)
38{
39 return current->flags & PF_KSWAPD;
40}
41
42/*
43 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
44 * be swapped to. The swap type and the offset into that swap type are
45 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits
46 * for the type means that the maximum number of swapcache pages is 27 bits
47 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
48 * the type/offset into the pte as 5/27 as well.
49 */
50#define MAX_SWAPFILES_SHIFT 5
51
52/*
53 * Use some of the swap files numbers for other purposes. This
54 * is a convenient way to hook into the VM to trigger special
55 * actions on faults.
56 */
57
58/*
59 * Unaddressable device memory support. See include/linux/hmm.h and
60 * Documentation/vm/hmm.rst. Short description is we need struct pages for
61 * device memory that is unaddressable (inaccessible) by CPU, so that we can
62 * migrate part of a process memory to device memory.
63 *
64 * When a page is migrated from CPU to device, we set the CPU page table entry
65 * to a special SWP_DEVICE_{READ|WRITE} entry.
66 *
67 * When a page is mapped by the device for exclusive access we set the CPU page
68 * table entries to special SWP_DEVICE_EXCLUSIVE_* entries.
69 */
70#ifdef CONFIG_DEVICE_PRIVATE
71#define SWP_DEVICE_NUM 4
72#define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM)
73#define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1)
74#define SWP_DEVICE_EXCLUSIVE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2)
75#define SWP_DEVICE_EXCLUSIVE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+3)
76#else
77#define SWP_DEVICE_NUM 0
78#endif
79
80/*
81 * NUMA node memory migration support
82 */
83#ifdef CONFIG_MIGRATION
84#define SWP_MIGRATION_NUM 2
85#define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
86#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
87#else
88#define SWP_MIGRATION_NUM 0
89#endif
90
91/*
92 * Handling of hardware poisoned pages with memory corruption.
93 */
94#ifdef CONFIG_MEMORY_FAILURE
95#define SWP_HWPOISON_NUM 1
96#define SWP_HWPOISON MAX_SWAPFILES
97#else
98#define SWP_HWPOISON_NUM 0
99#endif
100
101#define MAX_SWAPFILES \
102 ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \
103 SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)
104
105/*
106 * Magic header for a swap area. The first part of the union is
107 * what the swap magic looks like for the old (limited to 128MB)
108 * swap area format, the second part of the union adds - in the
109 * old reserved area - some extra information. Note that the first
110 * kilobyte is reserved for boot loader or disk label stuff...
111 *
112 * Having the magic at the end of the PAGE_SIZE makes detecting swap
113 * areas somewhat tricky on machines that support multiple page sizes.
114 * For 2.5 we'll probably want to move the magic to just beyond the
115 * bootbits...
116 */
117union swap_header {
118 struct {
119 char reserved[PAGE_SIZE - 10];
120 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
121 } magic;
122 struct {
123 char bootbits[1024]; /* Space for disklabel etc. */
124 __u32 version;
125 __u32 last_page;
126 __u32 nr_badpages;
127 unsigned char sws_uuid[16];
128 unsigned char sws_volume[16];
129 __u32 padding[117];
130 __u32 badpages[1];
131 } info;
132};
133
134/*
135 * current->reclaim_state points to one of these when a task is running
136 * memory reclaim
137 */
138struct reclaim_state {
139 unsigned long reclaimed_slab;
140};
141
142#ifdef __KERNEL__
143
144struct address_space;
145struct sysinfo;
146struct writeback_control;
147struct zone;
148
149/*
150 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
151 * disk blocks. A list of swap extents maps the entire swapfile. (Where the
152 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
153 * from setup, they're handled identically.
154 *
155 * We always assume that blocks are of size PAGE_SIZE.
156 */
157struct swap_extent {
158 struct rb_node rb_node;
159 pgoff_t start_page;
160 pgoff_t nr_pages;
161 sector_t start_block;
162};
163
164/*
165 * Max bad pages in the new format..
166 */
167#define MAX_SWAP_BADPAGES \
168 ((offsetof(union swap_header, magic.magic) - \
169 offsetof(union swap_header, info.badpages)) / sizeof(int))
170
171enum {
172 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
173 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
174 SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */
175 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
176 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
177 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
178 SWP_BLKDEV = (1 << 6), /* its a block device */
179 SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */
180 SWP_FS_OPS = (1 << 8), /* swapfile operations go through fs */
181 SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */
182 SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */
183 SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */
184 SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */
185 /* add others here before... */
186 SWP_SCANNING = (1 << 14), /* refcount in scan_swap_map */
187};
188
189#define SWAP_CLUSTER_MAX 32UL
190#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
191
192/* Bit flag in swap_map */
193#define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
194#define COUNT_CONTINUED 0x80 /* Flag swap_map continuation for full count */
195
196/* Special value in first swap_map */
197#define SWAP_MAP_MAX 0x3e /* Max count */
198#define SWAP_MAP_BAD 0x3f /* Note page is bad */
199#define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs */
200
201/* Special value in each swap_map continuation */
202#define SWAP_CONT_MAX 0x7f /* Max count */
203
204/*
205 * We use this to track usage of a cluster. A cluster is a block of swap disk
206 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All
207 * free clusters are organized into a list. We fetch an entry from the list to
208 * get a free cluster.
209 *
210 * The data field stores next cluster if the cluster is free or cluster usage
211 * counter otherwise. The flags field determines if a cluster is free. This is
212 * protected by swap_info_struct.lock.
213 */
214struct swap_cluster_info {
215 spinlock_t lock; /*
216 * Protect swap_cluster_info fields
217 * and swap_info_struct->swap_map
218 * elements correspond to the swap
219 * cluster
220 */
221 unsigned int data:24;
222 unsigned int flags:8;
223};
224#define CLUSTER_FLAG_FREE 1 /* This cluster is free */
225#define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */
226#define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */
227
228/*
229 * We assign a cluster to each CPU, so each CPU can allocate swap entry from
230 * its own cluster and swapout sequentially. The purpose is to optimize swapout
231 * throughput.
232 */
233struct percpu_cluster {
234 struct swap_cluster_info index; /* Current cluster index */
235 unsigned int next; /* Likely next allocation offset */
236};
237
238struct swap_cluster_list {
239 struct swap_cluster_info head;
240 struct swap_cluster_info tail;
241};
242
243/*
244 * The in-memory structure used to track swap areas.
245 */
246struct swap_info_struct {
247 struct percpu_ref users; /* indicate and keep swap device valid. */
248 unsigned long flags; /* SWP_USED etc: see above */
249 signed short prio; /* swap priority of this type */
250 struct plist_node list; /* entry in swap_active_head */
251 signed char type; /* strange name for an index */
252 unsigned int max; /* extent of the swap_map */
253 unsigned char *swap_map; /* vmalloc'ed array of usage counts */
254 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
255 struct swap_cluster_list free_clusters; /* free clusters list */
256 unsigned int lowest_bit; /* index of first free in swap_map */
257 unsigned int highest_bit; /* index of last free in swap_map */
258 unsigned int pages; /* total of usable pages of swap */
259 unsigned int inuse_pages; /* number of those currently in use */
260 unsigned int cluster_next; /* likely index for next allocation */
261 unsigned int cluster_nr; /* countdown to next cluster search */
262 unsigned int __percpu *cluster_next_cpu; /*percpu index for next allocation */
263 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
264 struct rb_root swap_extent_root;/* root of the swap extent rbtree */
265 struct block_device *bdev; /* swap device or bdev of swap file */
266 struct file *swap_file; /* seldom referenced */
267 unsigned int old_block_size; /* seldom referenced */
268 struct completion comp; /* seldom referenced */
269#ifdef CONFIG_FRONTSWAP
270 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */
271 atomic_t frontswap_pages; /* frontswap pages in-use counter */
272#endif
273 spinlock_t lock; /*
274 * protect map scan related fields like
275 * swap_map, lowest_bit, highest_bit,
276 * inuse_pages, cluster_next,
277 * cluster_nr, lowest_alloc,
278 * highest_alloc, free/discard cluster
279 * list. other fields are only changed
280 * at swapon/swapoff, so are protected
281 * by swap_lock. changing flags need
282 * hold this lock and swap_lock. If
283 * both locks need hold, hold swap_lock
284 * first.
285 */
286 spinlock_t cont_lock; /*
287 * protect swap count continuation page
288 * list.
289 */
290 struct work_struct discard_work; /* discard worker */
291 struct swap_cluster_list discard_clusters; /* discard clusters list */
292 struct plist_node avail_lists[]; /*
293 * entries in swap_avail_heads, one
294 * entry per node.
295 * Must be last as the number of the
296 * array is nr_node_ids, which is not
297 * a fixed value so have to allocate
298 * dynamically.
299 * And it has to be an array so that
300 * plist_for_each_* can work.
301 */
302};
303
304#ifdef CONFIG_64BIT
305#define SWAP_RA_ORDER_CEILING 5
306#else
307/* Avoid stack overflow, because we need to save part of page table */
308#define SWAP_RA_ORDER_CEILING 3
309#define SWAP_RA_PTE_CACHE_SIZE (1 << SWAP_RA_ORDER_CEILING)
310#endif
311
312struct vma_swap_readahead {
313 unsigned short win;
314 unsigned short offset;
315 unsigned short nr_pte;
316#ifdef CONFIG_64BIT
317 pte_t *ptes;
318#else
319 pte_t ptes[SWAP_RA_PTE_CACHE_SIZE];
320#endif
321};
322
323static inline swp_entry_t folio_swap_entry(struct folio *folio)
324{
325 swp_entry_t entry = { .val = page_private(&folio->page) };
326 return entry;
327}
328
329/* linux/mm/workingset.c */
330void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages);
331void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg);
332void workingset_refault(struct folio *folio, void *shadow);
333void workingset_activation(struct folio *folio);
334
335/* Only track the nodes of mappings with shadow entries */
336void workingset_update_node(struct xa_node *node);
337#define mapping_set_update(xas, mapping) do { \
338 if (!dax_mapping(mapping) && !shmem_mapping(mapping)) \
339 xas_set_update(xas, workingset_update_node); \
340} while (0)
341
342/* linux/mm/page_alloc.c */
343extern unsigned long totalreserve_pages;
344
345/* Definition of global_zone_page_state not available yet */
346#define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
347
348
349/* linux/mm/swap.c */
350extern void lru_note_cost(struct lruvec *lruvec, bool file,
351 unsigned int nr_pages);
352extern void lru_note_cost_folio(struct folio *);
353extern void folio_add_lru(struct folio *);
354extern void lru_cache_add(struct page *);
355void mark_page_accessed(struct page *);
356void folio_mark_accessed(struct folio *);
357
358extern atomic_t lru_disable_count;
359
360static inline bool lru_cache_disabled(void)
361{
362 return atomic_read(&lru_disable_count);
363}
364
365static inline void lru_cache_enable(void)
366{
367 atomic_dec(&lru_disable_count);
368}
369
370extern void lru_cache_disable(void);
371extern void lru_add_drain(void);
372extern void lru_add_drain_cpu(int cpu);
373extern void lru_add_drain_cpu_zone(struct zone *zone);
374extern void lru_add_drain_all(void);
375extern void deactivate_file_page(struct page *page);
376extern void deactivate_page(struct page *page);
377extern void mark_page_lazyfree(struct page *page);
378extern void swap_setup(void);
379
380extern void lru_cache_add_inactive_or_unevictable(struct page *page,
381 struct vm_area_struct *vma);
382
383/* linux/mm/vmscan.c */
384extern unsigned long zone_reclaimable_pages(struct zone *zone);
385extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
386 gfp_t gfp_mask, nodemask_t *mask);
387extern bool __isolate_lru_page_prepare(struct page *page, isolate_mode_t mode);
388extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
389 unsigned long nr_pages,
390 gfp_t gfp_mask,
391 bool may_swap);
392extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
393 gfp_t gfp_mask, bool noswap,
394 pg_data_t *pgdat,
395 unsigned long *nr_scanned);
396extern unsigned long shrink_all_memory(unsigned long nr_pages);
397extern int vm_swappiness;
398extern int remove_mapping(struct address_space *mapping, struct page *page);
399
400extern unsigned long reclaim_pages(struct list_head *page_list);
401#ifdef CONFIG_NUMA
402extern int node_reclaim_mode;
403extern int sysctl_min_unmapped_ratio;
404extern int sysctl_min_slab_ratio;
405#else
406#define node_reclaim_mode 0
407#endif
408
409static inline bool node_reclaim_enabled(void)
410{
411 /* Is any node_reclaim_mode bit set? */
412 return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP);
413}
414
415extern void check_move_unevictable_pages(struct pagevec *pvec);
416
417extern void kswapd_run(int nid);
418extern void kswapd_stop(int nid);
419
420#ifdef CONFIG_SWAP
421
422#include <linux/blk_types.h> /* for bio_end_io_t */
423
424/* linux/mm/page_io.c */
425extern int swap_readpage(struct page *page, bool do_poll);
426extern int swap_writepage(struct page *page, struct writeback_control *wbc);
427extern void end_swap_bio_write(struct bio *bio);
428extern int __swap_writepage(struct page *page, struct writeback_control *wbc,
429 bio_end_io_t end_write_func);
430extern int swap_set_page_dirty(struct page *page);
431
432int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
433 unsigned long nr_pages, sector_t start_block);
434int generic_swapfile_activate(struct swap_info_struct *, struct file *,
435 sector_t *);
436
437/* linux/mm/swap_state.c */
438/* One swap address space for each 64M swap space */
439#define SWAP_ADDRESS_SPACE_SHIFT 14
440#define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT)
441extern struct address_space *swapper_spaces[];
442#define swap_address_space(entry) \
443 (&swapper_spaces[swp_type(entry)][swp_offset(entry) \
444 >> SWAP_ADDRESS_SPACE_SHIFT])
445static inline unsigned long total_swapcache_pages(void)
446{
447 return global_node_page_state(NR_SWAPCACHE);
448}
449
450extern void show_swap_cache_info(void);
451extern int add_to_swap(struct page *page);
452extern void *get_shadow_from_swap_cache(swp_entry_t entry);
453extern int add_to_swap_cache(struct page *page, swp_entry_t entry,
454 gfp_t gfp, void **shadowp);
455extern void __delete_from_swap_cache(struct page *page,
456 swp_entry_t entry, void *shadow);
457extern void delete_from_swap_cache(struct page *);
458extern void clear_shadow_from_swap_cache(int type, unsigned long begin,
459 unsigned long end);
460extern void free_swap_cache(struct page *);
461extern void free_page_and_swap_cache(struct page *);
462extern void free_pages_and_swap_cache(struct page **, int);
463extern struct page *lookup_swap_cache(swp_entry_t entry,
464 struct vm_area_struct *vma,
465 unsigned long addr);
466struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index);
467extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
468 struct vm_area_struct *vma, unsigned long addr,
469 bool do_poll);
470extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t,
471 struct vm_area_struct *vma, unsigned long addr,
472 bool *new_page_allocated);
473extern struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
474 struct vm_fault *vmf);
475extern struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
476 struct vm_fault *vmf);
477
478/* linux/mm/swapfile.c */
479extern atomic_long_t nr_swap_pages;
480extern long total_swap_pages;
481extern atomic_t nr_rotate_swap;
482extern bool has_usable_swap(void);
483
484/* Swap 50% full? Release swapcache more aggressively.. */
485static inline bool vm_swap_full(void)
486{
487 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
488}
489
490static inline long get_nr_swap_pages(void)
491{
492 return atomic_long_read(&nr_swap_pages);
493}
494
495extern void si_swapinfo(struct sysinfo *);
496extern swp_entry_t get_swap_page(struct page *page);
497extern void put_swap_page(struct page *page, swp_entry_t entry);
498extern swp_entry_t get_swap_page_of_type(int);
499extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size);
500extern int add_swap_count_continuation(swp_entry_t, gfp_t);
501extern void swap_shmem_alloc(swp_entry_t);
502extern int swap_duplicate(swp_entry_t);
503extern int swapcache_prepare(swp_entry_t);
504extern void swap_free(swp_entry_t);
505extern void swapcache_free_entries(swp_entry_t *entries, int n);
506extern int free_swap_and_cache(swp_entry_t);
507int swap_type_of(dev_t device, sector_t offset);
508int find_first_swap(dev_t *device);
509extern unsigned int count_swap_pages(int, int);
510extern sector_t swapdev_block(int, pgoff_t);
511extern int page_swapcount(struct page *);
512extern int __swap_count(swp_entry_t entry);
513extern int __swp_swapcount(swp_entry_t entry);
514extern int swp_swapcount(swp_entry_t entry);
515extern struct swap_info_struct *page_swap_info(struct page *);
516extern struct swap_info_struct *swp_swap_info(swp_entry_t entry);
517extern bool reuse_swap_page(struct page *, int *);
518extern int try_to_free_swap(struct page *);
519struct backing_dev_info;
520extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
521extern void exit_swap_address_space(unsigned int type);
522extern struct swap_info_struct *get_swap_device(swp_entry_t entry);
523sector_t swap_page_sector(struct page *page);
524
525static inline void put_swap_device(struct swap_info_struct *si)
526{
527 percpu_ref_put(&si->users);
528}
529
530#else /* CONFIG_SWAP */
531
532static inline int swap_readpage(struct page *page, bool do_poll)
533{
534 return 0;
535}
536
537static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry)
538{
539 return NULL;
540}
541
542static inline struct swap_info_struct *get_swap_device(swp_entry_t entry)
543{
544 return NULL;
545}
546
547static inline void put_swap_device(struct swap_info_struct *si)
548{
549}
550
551static inline struct address_space *swap_address_space(swp_entry_t entry)
552{
553 return NULL;
554}
555
556#define get_nr_swap_pages() 0L
557#define total_swap_pages 0L
558#define total_swapcache_pages() 0UL
559#define vm_swap_full() 0
560
561#define si_swapinfo(val) \
562 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
563/* only sparc can not include linux/pagemap.h in this file
564 * so leave put_page and release_pages undeclared... */
565#define free_page_and_swap_cache(page) \
566 put_page(page)
567#define free_pages_and_swap_cache(pages, nr) \
568 release_pages((pages), (nr));
569
570static inline void free_swap_cache(struct page *page)
571{
572}
573
574static inline void show_swap_cache_info(void)
575{
576}
577
578/* used to sanity check ptes in zap_pte_range when CONFIG_SWAP=0 */
579#define free_swap_and_cache(e) is_pfn_swap_entry(e)
580
581static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
582{
583 return 0;
584}
585
586static inline void swap_shmem_alloc(swp_entry_t swp)
587{
588}
589
590static inline int swap_duplicate(swp_entry_t swp)
591{
592 return 0;
593}
594
595static inline void swap_free(swp_entry_t swp)
596{
597}
598
599static inline void put_swap_page(struct page *page, swp_entry_t swp)
600{
601}
602
603static inline struct page *swap_cluster_readahead(swp_entry_t entry,
604 gfp_t gfp_mask, struct vm_fault *vmf)
605{
606 return NULL;
607}
608
609static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
610 struct vm_fault *vmf)
611{
612 return NULL;
613}
614
615static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
616{
617 return 0;
618}
619
620static inline struct page *lookup_swap_cache(swp_entry_t swp,
621 struct vm_area_struct *vma,
622 unsigned long addr)
623{
624 return NULL;
625}
626
627static inline
628struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index)
629{
630 return find_get_page(mapping, index);
631}
632
633static inline int add_to_swap(struct page *page)
634{
635 return 0;
636}
637
638static inline void *get_shadow_from_swap_cache(swp_entry_t entry)
639{
640 return NULL;
641}
642
643static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
644 gfp_t gfp_mask, void **shadowp)
645{
646 return -1;
647}
648
649static inline void __delete_from_swap_cache(struct page *page,
650 swp_entry_t entry, void *shadow)
651{
652}
653
654static inline void delete_from_swap_cache(struct page *page)
655{
656}
657
658static inline void clear_shadow_from_swap_cache(int type, unsigned long begin,
659 unsigned long end)
660{
661}
662
663static inline int page_swapcount(struct page *page)
664{
665 return 0;
666}
667
668static inline int __swap_count(swp_entry_t entry)
669{
670 return 0;
671}
672
673static inline int __swp_swapcount(swp_entry_t entry)
674{
675 return 0;
676}
677
678static inline int swp_swapcount(swp_entry_t entry)
679{
680 return 0;
681}
682
683#define reuse_swap_page(page, total_map_swapcount) \
684 (page_trans_huge_mapcount(page, total_map_swapcount) == 1)
685
686static inline int try_to_free_swap(struct page *page)
687{
688 return 0;
689}
690
691static inline swp_entry_t get_swap_page(struct page *page)
692{
693 swp_entry_t entry;
694 entry.val = 0;
695 return entry;
696}
697
698#endif /* CONFIG_SWAP */
699
700#ifdef CONFIG_THP_SWAP
701extern int split_swap_cluster(swp_entry_t entry);
702#else
703static inline int split_swap_cluster(swp_entry_t entry)
704{
705 return 0;
706}
707#endif
708
709#ifdef CONFIG_MEMCG
710static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
711{
712 /* Cgroup2 doesn't have per-cgroup swappiness */
713 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
714 return vm_swappiness;
715
716 /* root ? */
717 if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg))
718 return vm_swappiness;
719
720 return memcg->swappiness;
721}
722#else
723static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
724{
725 return vm_swappiness;
726}
727#endif
728
729#if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
730extern void __cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask);
731static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
732{
733 if (mem_cgroup_disabled())
734 return;
735 __cgroup_throttle_swaprate(page, gfp_mask);
736}
737#else
738static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
739{
740}
741#endif
742
743#ifdef CONFIG_MEMCG_SWAP
744extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);
745extern int __mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);
746static inline int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
747{
748 if (mem_cgroup_disabled())
749 return 0;
750 return __mem_cgroup_try_charge_swap(page, entry);
751}
752
753extern void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
754static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
755{
756 if (mem_cgroup_disabled())
757 return;
758 __mem_cgroup_uncharge_swap(entry, nr_pages);
759}
760
761extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
762extern bool mem_cgroup_swap_full(struct page *page);
763#else
764static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
765{
766}
767
768static inline int mem_cgroup_try_charge_swap(struct page *page,
769 swp_entry_t entry)
770{
771 return 0;
772}
773
774static inline void mem_cgroup_uncharge_swap(swp_entry_t entry,
775 unsigned int nr_pages)
776{
777}
778
779static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
780{
781 return get_nr_swap_pages();
782}
783
784static inline bool mem_cgroup_swap_full(struct page *page)
785{
786 return vm_swap_full();
787}
788#endif
789
790#endif /* __KERNEL__*/
791#endif /* _LINUX_SWAP_H */