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
19 struct notifier_block;
20
21 struct bio;
22
23 struct 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
current_is_kswapd(void)37 static 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 * PTE markers are used to persist information onto PTEs that otherwise
60 * should be a none pte. As its name "PTE" hints, it should only be
61 * applied to the leaves of pgtables.
62 */
63 #define SWP_PTE_MARKER_NUM 1
64 #define SWP_PTE_MARKER (MAX_SWAPFILES + SWP_HWPOISON_NUM + \
65 SWP_MIGRATION_NUM + SWP_DEVICE_NUM)
66
67 /*
68 * Unaddressable device memory support. See include/linux/hmm.h and
69 * Documentation/mm/hmm.rst. Short description is we need struct pages for
70 * device memory that is unaddressable (inaccessible) by CPU, so that we can
71 * migrate part of a process memory to device memory.
72 *
73 * When a page is migrated from CPU to device, we set the CPU page table entry
74 * to a special SWP_DEVICE_{READ|WRITE} entry.
75 *
76 * When a page is mapped by the device for exclusive access we set the CPU page
77 * table entries to special SWP_DEVICE_EXCLUSIVE_* entries.
78 */
79 #ifdef CONFIG_DEVICE_PRIVATE
80 #define SWP_DEVICE_NUM 4
81 #define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM)
82 #define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1)
83 #define SWP_DEVICE_EXCLUSIVE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2)
84 #define SWP_DEVICE_EXCLUSIVE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+3)
85 #else
86 #define SWP_DEVICE_NUM 0
87 #endif
88
89 /*
90 * Page migration support.
91 *
92 * SWP_MIGRATION_READ_EXCLUSIVE is only applicable to anonymous pages and
93 * indicates that the referenced (part of) an anonymous page is exclusive to
94 * a single process. For SWP_MIGRATION_WRITE, that information is implicit:
95 * (part of) an anonymous page that are mapped writable are exclusive to a
96 * single process.
97 */
98 #ifdef CONFIG_MIGRATION
99 #define SWP_MIGRATION_NUM 3
100 #define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
101 #define SWP_MIGRATION_READ_EXCLUSIVE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
102 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 2)
103 #else
104 #define SWP_MIGRATION_NUM 0
105 #endif
106
107 /*
108 * Handling of hardware poisoned pages with memory corruption.
109 */
110 #ifdef CONFIG_MEMORY_FAILURE
111 #define SWP_HWPOISON_NUM 1
112 #define SWP_HWPOISON MAX_SWAPFILES
113 #else
114 #define SWP_HWPOISON_NUM 0
115 #endif
116
117 #define MAX_SWAPFILES \
118 ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \
119 SWP_MIGRATION_NUM - SWP_HWPOISON_NUM - \
120 SWP_PTE_MARKER_NUM)
121
122 /*
123 * Magic header for a swap area. The first part of the union is
124 * what the swap magic looks like for the old (limited to 128MB)
125 * swap area format, the second part of the union adds - in the
126 * old reserved area - some extra information. Note that the first
127 * kilobyte is reserved for boot loader or disk label stuff...
128 *
129 * Having the magic at the end of the PAGE_SIZE makes detecting swap
130 * areas somewhat tricky on machines that support multiple page sizes.
131 * For 2.5 we'll probably want to move the magic to just beyond the
132 * bootbits...
133 */
134 union swap_header {
135 struct {
136 char reserved[PAGE_SIZE - 10];
137 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
138 } magic;
139 struct {
140 char bootbits[1024]; /* Space for disklabel etc. */
141 __u32 version;
142 __u32 last_page;
143 __u32 nr_badpages;
144 unsigned char sws_uuid[16];
145 unsigned char sws_volume[16];
146 __u32 padding[117];
147 __u32 badpages[1];
148 } info;
149 };
150
151 /*
152 * current->reclaim_state points to one of these when a task is running
153 * memory reclaim
154 */
155 struct reclaim_state {
156 /* pages reclaimed outside of LRU-based reclaim */
157 unsigned long reclaimed;
158 #ifdef CONFIG_LRU_GEN
159 /* per-thread mm walk data */
160 struct lru_gen_mm_walk *mm_walk;
161 #endif
162 };
163
164 /*
165 * mm_account_reclaimed_pages(): account reclaimed pages outside of LRU-based
166 * reclaim
167 * @pages: number of pages reclaimed
168 *
169 * If the current process is undergoing a reclaim operation, increment the
170 * number of reclaimed pages by @pages.
171 */
mm_account_reclaimed_pages(unsigned long pages)172 static inline void mm_account_reclaimed_pages(unsigned long pages)
173 {
174 if (current->reclaim_state)
175 current->reclaim_state->reclaimed += pages;
176 }
177
178 #ifdef __KERNEL__
179
180 struct address_space;
181 struct sysinfo;
182 struct writeback_control;
183 struct zone;
184
185 /*
186 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
187 * disk blocks. A rbtree of swap extents maps the entire swapfile (Where the
188 * term `swapfile' refers to either a blockdevice or an IS_REG file). Apart
189 * from setup, they're handled identically.
190 *
191 * We always assume that blocks are of size PAGE_SIZE.
192 */
193 struct swap_extent {
194 struct rb_node rb_node;
195 pgoff_t start_page;
196 pgoff_t nr_pages;
197 sector_t start_block;
198 };
199
200 /*
201 * Max bad pages in the new format..
202 */
203 #define MAX_SWAP_BADPAGES \
204 ((offsetof(union swap_header, magic.magic) - \
205 offsetof(union swap_header, info.badpages)) / sizeof(int))
206
207 enum {
208 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
209 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
210 SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */
211 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
212 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
213 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
214 SWP_BLKDEV = (1 << 6), /* its a block device */
215 SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */
216 SWP_FS_OPS = (1 << 8), /* swapfile operations go through fs */
217 SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */
218 SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */
219 SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */
220 SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */
221 /* add others here before... */
222 };
223
224 #define SWAP_CLUSTER_MAX 32UL
225 #define SWAP_CLUSTER_MAX_SKIPPED (SWAP_CLUSTER_MAX << 10)
226 #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
227
228 /* Bit flag in swap_map */
229 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
230 #define COUNT_CONTINUED 0x80 /* Flag swap_map continuation for full count */
231
232 /* Special value in first swap_map */
233 #define SWAP_MAP_MAX 0x3e /* Max count */
234 #define SWAP_MAP_BAD 0x3f /* Note page is bad */
235 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs */
236
237 /* Special value in each swap_map continuation */
238 #define SWAP_CONT_MAX 0x7f /* Max count */
239
240 /*
241 * We use this to track usage of a cluster. A cluster is a block of swap disk
242 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All
243 * free clusters are organized into a list. We fetch an entry from the list to
244 * get a free cluster.
245 *
246 * The flags field determines if a cluster is free. This is
247 * protected by cluster lock.
248 */
249 struct swap_cluster_info {
250 spinlock_t lock; /*
251 * Protect swap_cluster_info fields
252 * other than list, and swap_info_struct->swap_map
253 * elements corresponding to the swap cluster.
254 */
255 u16 count;
256 u8 flags;
257 u8 order;
258 struct list_head list;
259 };
260
261 /* All on-list cluster must have a non-zero flag. */
262 enum swap_cluster_flags {
263 CLUSTER_FLAG_NONE = 0, /* For temporary off-list cluster */
264 CLUSTER_FLAG_FREE,
265 CLUSTER_FLAG_NONFULL,
266 CLUSTER_FLAG_FRAG,
267 /* Clusters with flags above are allocatable */
268 CLUSTER_FLAG_USABLE = CLUSTER_FLAG_FRAG,
269 CLUSTER_FLAG_FULL,
270 CLUSTER_FLAG_DISCARD,
271 CLUSTER_FLAG_MAX,
272 };
273
274 /*
275 * The first page in the swap file is the swap header, which is always marked
276 * bad to prevent it from being allocated as an entry. This also prevents the
277 * cluster to which it belongs being marked free. Therefore 0 is safe to use as
278 * a sentinel to indicate an entry is not valid.
279 */
280 #define SWAP_ENTRY_INVALID 0
281
282 #ifdef CONFIG_THP_SWAP
283 #define SWAP_NR_ORDERS (PMD_ORDER + 1)
284 #else
285 #define SWAP_NR_ORDERS 1
286 #endif
287
288 /*
289 * We assign a cluster to each CPU, so each CPU can allocate swap entry from
290 * its own cluster and swapout sequentially. The purpose is to optimize swapout
291 * throughput.
292 */
293 struct percpu_cluster {
294 local_lock_t lock; /* Protect the percpu_cluster above */
295 unsigned int next[SWAP_NR_ORDERS]; /* Likely next allocation offset */
296 };
297
298 /*
299 * The in-memory structure used to track swap areas.
300 */
301 struct swap_info_struct {
302 struct percpu_ref users; /* indicate and keep swap device valid. */
303 unsigned long flags; /* SWP_USED etc: see above */
304 signed short prio; /* swap priority of this type */
305 struct plist_node list; /* entry in swap_active_head */
306 signed char type; /* strange name for an index */
307 unsigned int max; /* extent of the swap_map */
308 unsigned char *swap_map; /* vmalloc'ed array of usage counts */
309 unsigned long *zeromap; /* kvmalloc'ed bitmap to track zero pages */
310 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
311 struct list_head free_clusters; /* free clusters list */
312 struct list_head full_clusters; /* full clusters list */
313 struct list_head nonfull_clusters[SWAP_NR_ORDERS];
314 /* list of cluster that contains at least one free slot */
315 struct list_head frag_clusters[SWAP_NR_ORDERS];
316 /* list of cluster that are fragmented or contented */
317 atomic_long_t frag_cluster_nr[SWAP_NR_ORDERS];
318 unsigned int pages; /* total of usable pages of swap */
319 atomic_long_t inuse_pages; /* number of those currently in use */
320 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
321 struct percpu_cluster *global_cluster; /* Use one global cluster for rotating device */
322 spinlock_t global_cluster_lock; /* Serialize usage of global cluster */
323 struct rb_root swap_extent_root;/* root of the swap extent rbtree */
324 struct block_device *bdev; /* swap device or bdev of swap file */
325 struct file *swap_file; /* seldom referenced */
326 struct completion comp; /* seldom referenced */
327 spinlock_t lock; /*
328 * protect map scan related fields like
329 * swap_map, lowest_bit, highest_bit,
330 * inuse_pages, cluster_next,
331 * cluster_nr, lowest_alloc,
332 * highest_alloc, free/discard cluster
333 * list. other fields are only changed
334 * at swapon/swapoff, so are protected
335 * by swap_lock. changing flags need
336 * hold this lock and swap_lock. If
337 * both locks need hold, hold swap_lock
338 * first.
339 */
340 spinlock_t cont_lock; /*
341 * protect swap count continuation page
342 * list.
343 */
344 struct work_struct discard_work; /* discard worker */
345 struct work_struct reclaim_work; /* reclaim worker */
346 struct list_head discard_clusters; /* discard clusters list */
347 struct plist_node avail_lists[]; /*
348 * entries in swap_avail_heads, one
349 * entry per node.
350 * Must be last as the number of the
351 * array is nr_node_ids, which is not
352 * a fixed value so have to allocate
353 * dynamically.
354 * And it has to be an array so that
355 * plist_for_each_* can work.
356 */
357 };
358
page_swap_entry(struct page * page)359 static inline swp_entry_t page_swap_entry(struct page *page)
360 {
361 struct folio *folio = page_folio(page);
362 swp_entry_t entry = folio->swap;
363
364 entry.val += folio_page_idx(folio, page);
365 return entry;
366 }
367
368 /* linux/mm/workingset.c */
369 bool workingset_test_recent(void *shadow, bool file, bool *workingset,
370 bool flush);
371 void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages);
372 void *workingset_eviction(struct folio *folio, struct mem_cgroup *target_memcg);
373 void workingset_refault(struct folio *folio, void *shadow);
374 void workingset_activation(struct folio *folio);
375
376 /* linux/mm/page_alloc.c */
377 extern unsigned long totalreserve_pages;
378
379 /* Definition of global_zone_page_state not available yet */
380 #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
381
382
383 /* linux/mm/swap.c */
384 void lru_note_cost(struct lruvec *lruvec, bool file,
385 unsigned int nr_io, unsigned int nr_rotated);
386 void lru_note_cost_refault(struct folio *);
387 void folio_add_lru(struct folio *);
388 void folio_add_lru_vma(struct folio *, struct vm_area_struct *);
389 void mark_page_accessed(struct page *);
390 void folio_mark_accessed(struct folio *);
391
392 extern atomic_t lru_disable_count;
393
lru_cache_disabled(void)394 static inline bool lru_cache_disabled(void)
395 {
396 return atomic_read(&lru_disable_count);
397 }
398
lru_cache_enable(void)399 static inline void lru_cache_enable(void)
400 {
401 atomic_dec(&lru_disable_count);
402 }
403
404 extern void lru_cache_disable(void);
405 extern void lru_add_drain(void);
406 extern void lru_add_drain_cpu(int cpu);
407 extern void lru_add_drain_cpu_zone(struct zone *zone);
408 extern void lru_add_drain_all(void);
409 void folio_deactivate(struct folio *folio);
410 void folio_mark_lazyfree(struct folio *folio);
411 extern void swap_setup(void);
412
413 /* linux/mm/vmscan.c */
414 extern unsigned long zone_reclaimable_pages(struct zone *zone);
415 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
416 gfp_t gfp_mask, nodemask_t *mask);
417
418 #define MEMCG_RECLAIM_MAY_SWAP (1 << 1)
419 #define MEMCG_RECLAIM_PROACTIVE (1 << 2)
420 #define MIN_SWAPPINESS 0
421 #define MAX_SWAPPINESS 200
422 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
423 unsigned long nr_pages,
424 gfp_t gfp_mask,
425 unsigned int reclaim_options,
426 int *swappiness);
427 extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
428 gfp_t gfp_mask, bool noswap,
429 pg_data_t *pgdat,
430 unsigned long *nr_scanned);
431 extern unsigned long shrink_all_memory(unsigned long nr_pages);
432 extern int vm_swappiness;
433 long remove_mapping(struct address_space *mapping, struct folio *folio);
434
435 #ifdef CONFIG_NUMA
436 extern int sysctl_min_unmapped_ratio;
437 extern int sysctl_min_slab_ratio;
438 #endif
439
440 void check_move_unevictable_folios(struct folio_batch *fbatch);
441
442 extern void __meminit kswapd_run(int nid);
443 extern void __meminit kswapd_stop(int nid);
444
445 #ifdef CONFIG_SWAP
446
447 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
448 unsigned long nr_pages, sector_t start_block);
449 int generic_swapfile_activate(struct swap_info_struct *, struct file *,
450 sector_t *);
451
total_swapcache_pages(void)452 static inline unsigned long total_swapcache_pages(void)
453 {
454 return global_node_page_state(NR_SWAPCACHE);
455 }
456
457 void free_swap_cache(struct folio *folio);
458 void free_page_and_swap_cache(struct page *);
459 void free_pages_and_swap_cache(struct encoded_page **, int);
460 /* linux/mm/swapfile.c */
461 extern atomic_long_t nr_swap_pages;
462 extern long total_swap_pages;
463 extern atomic_t nr_rotate_swap;
464 extern bool has_usable_swap(void);
465
466 /* Swap 50% full? Release swapcache more aggressively.. */
vm_swap_full(void)467 static inline bool vm_swap_full(void)
468 {
469 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
470 }
471
get_nr_swap_pages(void)472 static inline long get_nr_swap_pages(void)
473 {
474 return atomic_long_read(&nr_swap_pages);
475 }
476
477 extern void si_swapinfo(struct sysinfo *);
478 swp_entry_t folio_alloc_swap(struct folio *folio);
479 bool folio_free_swap(struct folio *folio);
480 void put_swap_folio(struct folio *folio, swp_entry_t entry);
481 extern swp_entry_t get_swap_page_of_type(int);
482 extern int get_swap_pages(int n, swp_entry_t swp_entries[], int order);
483 extern int add_swap_count_continuation(swp_entry_t, gfp_t);
484 extern void swap_shmem_alloc(swp_entry_t, int);
485 extern int swap_duplicate(swp_entry_t);
486 extern int swapcache_prepare(swp_entry_t entry, int nr);
487 extern void swap_free_nr(swp_entry_t entry, int nr_pages);
488 extern void swapcache_free_entries(swp_entry_t *entries, int n);
489 extern void free_swap_and_cache_nr(swp_entry_t entry, int nr);
490 int swap_type_of(dev_t device, sector_t offset);
491 int find_first_swap(dev_t *device);
492 extern unsigned int count_swap_pages(int, int);
493 extern sector_t swapdev_block(int, pgoff_t);
494 extern int __swap_count(swp_entry_t entry);
495 extern int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry);
496 extern int swp_swapcount(swp_entry_t entry);
497 struct swap_info_struct *swp_swap_info(swp_entry_t entry);
498 struct backing_dev_info;
499 extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
500 extern void exit_swap_address_space(unsigned int type);
501 extern struct swap_info_struct *get_swap_device(swp_entry_t entry);
502 sector_t swap_folio_sector(struct folio *folio);
503
put_swap_device(struct swap_info_struct * si)504 static inline void put_swap_device(struct swap_info_struct *si)
505 {
506 percpu_ref_put(&si->users);
507 }
508
509 #else /* CONFIG_SWAP */
swp_swap_info(swp_entry_t entry)510 static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry)
511 {
512 return NULL;
513 }
514
get_swap_device(swp_entry_t entry)515 static inline struct swap_info_struct *get_swap_device(swp_entry_t entry)
516 {
517 return NULL;
518 }
519
put_swap_device(struct swap_info_struct * si)520 static inline void put_swap_device(struct swap_info_struct *si)
521 {
522 }
523
524 #define get_nr_swap_pages() 0L
525 #define total_swap_pages 0L
526 #define total_swapcache_pages() 0UL
527 #define vm_swap_full() 0
528
529 #define si_swapinfo(val) \
530 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
531 /* only sparc can not include linux/pagemap.h in this file
532 * so leave put_page and release_pages undeclared... */
533 #define free_page_and_swap_cache(page) \
534 put_page(page)
535 #define free_pages_and_swap_cache(pages, nr) \
536 release_pages((pages), (nr));
537
free_swap_and_cache_nr(swp_entry_t entry,int nr)538 static inline void free_swap_and_cache_nr(swp_entry_t entry, int nr)
539 {
540 }
541
free_swap_cache(struct folio * folio)542 static inline void free_swap_cache(struct folio *folio)
543 {
544 }
545
add_swap_count_continuation(swp_entry_t swp,gfp_t gfp_mask)546 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
547 {
548 return 0;
549 }
550
swap_shmem_alloc(swp_entry_t swp,int nr)551 static inline void swap_shmem_alloc(swp_entry_t swp, int nr)
552 {
553 }
554
swap_duplicate(swp_entry_t swp)555 static inline int swap_duplicate(swp_entry_t swp)
556 {
557 return 0;
558 }
559
swapcache_prepare(swp_entry_t swp,int nr)560 static inline int swapcache_prepare(swp_entry_t swp, int nr)
561 {
562 return 0;
563 }
564
swap_free_nr(swp_entry_t entry,int nr_pages)565 static inline void swap_free_nr(swp_entry_t entry, int nr_pages)
566 {
567 }
568
put_swap_folio(struct folio * folio,swp_entry_t swp)569 static inline void put_swap_folio(struct folio *folio, swp_entry_t swp)
570 {
571 }
572
__swap_count(swp_entry_t entry)573 static inline int __swap_count(swp_entry_t entry)
574 {
575 return 0;
576 }
577
swap_swapcount(struct swap_info_struct * si,swp_entry_t entry)578 static inline int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry)
579 {
580 return 0;
581 }
582
swp_swapcount(swp_entry_t entry)583 static inline int swp_swapcount(swp_entry_t entry)
584 {
585 return 0;
586 }
587
folio_alloc_swap(struct folio * folio)588 static inline swp_entry_t folio_alloc_swap(struct folio *folio)
589 {
590 swp_entry_t entry;
591 entry.val = 0;
592 return entry;
593 }
594
folio_free_swap(struct folio * folio)595 static inline bool folio_free_swap(struct folio *folio)
596 {
597 return false;
598 }
599
add_swap_extent(struct swap_info_struct * sis,unsigned long start_page,unsigned long nr_pages,sector_t start_block)600 static 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
free_swap_and_cache(swp_entry_t entry)608 static inline void free_swap_and_cache(swp_entry_t entry)
609 {
610 free_swap_and_cache_nr(entry, 1);
611 }
612
swap_free(swp_entry_t entry)613 static inline void swap_free(swp_entry_t entry)
614 {
615 swap_free_nr(entry, 1);
616 }
617
618 #ifdef CONFIG_MEMCG
mem_cgroup_swappiness(struct mem_cgroup * memcg)619 static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
620 {
621 /* Cgroup2 doesn't have per-cgroup swappiness */
622 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
623 return READ_ONCE(vm_swappiness);
624
625 /* root ? */
626 if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg))
627 return READ_ONCE(vm_swappiness);
628
629 return READ_ONCE(memcg->swappiness);
630 }
631 #else
mem_cgroup_swappiness(struct mem_cgroup * mem)632 static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
633 {
634 return READ_ONCE(vm_swappiness);
635 }
636 #endif
637
638 #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
639 void __folio_throttle_swaprate(struct folio *folio, gfp_t gfp);
folio_throttle_swaprate(struct folio * folio,gfp_t gfp)640 static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp)
641 {
642 if (mem_cgroup_disabled())
643 return;
644 __folio_throttle_swaprate(folio, gfp);
645 }
646 #else
folio_throttle_swaprate(struct folio * folio,gfp_t gfp)647 static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp)
648 {
649 }
650 #endif
651
652 #if defined(CONFIG_MEMCG) && defined(CONFIG_SWAP)
653 void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry);
654 int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry);
mem_cgroup_try_charge_swap(struct folio * folio,swp_entry_t entry)655 static inline int mem_cgroup_try_charge_swap(struct folio *folio,
656 swp_entry_t entry)
657 {
658 if (mem_cgroup_disabled())
659 return 0;
660 return __mem_cgroup_try_charge_swap(folio, entry);
661 }
662
663 extern void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
mem_cgroup_uncharge_swap(swp_entry_t entry,unsigned int nr_pages)664 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
665 {
666 if (mem_cgroup_disabled())
667 return;
668 __mem_cgroup_uncharge_swap(entry, nr_pages);
669 }
670
671 extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
672 extern bool mem_cgroup_swap_full(struct folio *folio);
673 #else
mem_cgroup_swapout(struct folio * folio,swp_entry_t entry)674 static inline void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry)
675 {
676 }
677
mem_cgroup_try_charge_swap(struct folio * folio,swp_entry_t entry)678 static inline int mem_cgroup_try_charge_swap(struct folio *folio,
679 swp_entry_t entry)
680 {
681 return 0;
682 }
683
mem_cgroup_uncharge_swap(swp_entry_t entry,unsigned int nr_pages)684 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry,
685 unsigned int nr_pages)
686 {
687 }
688
mem_cgroup_get_nr_swap_pages(struct mem_cgroup * memcg)689 static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
690 {
691 return get_nr_swap_pages();
692 }
693
mem_cgroup_swap_full(struct folio * folio)694 static inline bool mem_cgroup_swap_full(struct folio *folio)
695 {
696 return vm_swap_full();
697 }
698 #endif
699
700 #endif /* __KERNEL__*/
701 #endif /* _LINUX_SWAP_H */
702