Line data Source code
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 :
37 : static inline int current_is_kswapd(void)
38 : {
39 0 : 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 : */
172 : static inline void mm_account_reclaimed_pages(unsigned long pages)
173 : {
174 0 : if (current->reclaim_state)
175 0 : 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 : SWP_SCANNING = (1 << 14), /* refcount in scan_swap_map */
223 : };
224 :
225 : #define SWAP_CLUSTER_MAX 32UL
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 data field stores next cluster if the cluster is free or cluster usage
247 : * counter otherwise. The flags field determines if a cluster is free. This is
248 : * protected by swap_info_struct.lock.
249 : */
250 : struct swap_cluster_info {
251 : spinlock_t lock; /*
252 : * Protect swap_cluster_info fields
253 : * and swap_info_struct->swap_map
254 : * elements correspond to the swap
255 : * cluster
256 : */
257 : unsigned int data:24;
258 : unsigned int flags:8;
259 : };
260 : #define CLUSTER_FLAG_FREE 1 /* This cluster is free */
261 : #define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */
262 : #define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */
263 :
264 : /*
265 : * We assign a cluster to each CPU, so each CPU can allocate swap entry from
266 : * its own cluster and swapout sequentially. The purpose is to optimize swapout
267 : * throughput.
268 : */
269 : struct percpu_cluster {
270 : struct swap_cluster_info index; /* Current cluster index */
271 : unsigned int next; /* Likely next allocation offset */
272 : };
273 :
274 : struct swap_cluster_list {
275 : struct swap_cluster_info head;
276 : struct swap_cluster_info tail;
277 : };
278 :
279 : /*
280 : * The in-memory structure used to track swap areas.
281 : */
282 : struct swap_info_struct {
283 : struct percpu_ref users; /* indicate and keep swap device valid. */
284 : unsigned long flags; /* SWP_USED etc: see above */
285 : signed short prio; /* swap priority of this type */
286 : struct plist_node list; /* entry in swap_active_head */
287 : signed char type; /* strange name for an index */
288 : unsigned int max; /* extent of the swap_map */
289 : unsigned char *swap_map; /* vmalloc'ed array of usage counts */
290 : struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
291 : struct swap_cluster_list free_clusters; /* free clusters list */
292 : unsigned int lowest_bit; /* index of first free in swap_map */
293 : unsigned int highest_bit; /* index of last free in swap_map */
294 : unsigned int pages; /* total of usable pages of swap */
295 : unsigned int inuse_pages; /* number of those currently in use */
296 : unsigned int cluster_next; /* likely index for next allocation */
297 : unsigned int cluster_nr; /* countdown to next cluster search */
298 : unsigned int __percpu *cluster_next_cpu; /*percpu index for next allocation */
299 : struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
300 : struct rb_root swap_extent_root;/* root of the swap extent rbtree */
301 : struct block_device *bdev; /* swap device or bdev of swap file */
302 : struct file *swap_file; /* seldom referenced */
303 : unsigned int old_block_size; /* seldom referenced */
304 : struct completion comp; /* seldom referenced */
305 : #ifdef CONFIG_FRONTSWAP
306 : unsigned long *frontswap_map; /* frontswap in-use, one bit per page */
307 : atomic_t frontswap_pages; /* frontswap pages in-use counter */
308 : #endif
309 : spinlock_t lock; /*
310 : * protect map scan related fields like
311 : * swap_map, lowest_bit, highest_bit,
312 : * inuse_pages, cluster_next,
313 : * cluster_nr, lowest_alloc,
314 : * highest_alloc, free/discard cluster
315 : * list. other fields are only changed
316 : * at swapon/swapoff, so are protected
317 : * by swap_lock. changing flags need
318 : * hold this lock and swap_lock. If
319 : * both locks need hold, hold swap_lock
320 : * first.
321 : */
322 : spinlock_t cont_lock; /*
323 : * protect swap count continuation page
324 : * list.
325 : */
326 : struct work_struct discard_work; /* discard worker */
327 : struct swap_cluster_list discard_clusters; /* discard clusters list */
328 : struct plist_node avail_lists[]; /*
329 : * entries in swap_avail_heads, one
330 : * entry per node.
331 : * Must be last as the number of the
332 : * array is nr_node_ids, which is not
333 : * a fixed value so have to allocate
334 : * dynamically.
335 : * And it has to be an array so that
336 : * plist_for_each_* can work.
337 : */
338 : };
339 :
340 : static inline swp_entry_t folio_swap_entry(struct folio *folio)
341 : {
342 0 : swp_entry_t entry = { .val = page_private(&folio->page) };
343 : return entry;
344 : }
345 :
346 : static inline void folio_set_swap_entry(struct folio *folio, swp_entry_t entry)
347 : {
348 0 : folio->private = (void *)entry.val;
349 : }
350 :
351 : /* linux/mm/workingset.c */
352 : bool workingset_test_recent(void *shadow, bool file, bool *workingset);
353 : void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages);
354 : void *workingset_eviction(struct folio *folio, struct mem_cgroup *target_memcg);
355 : void workingset_refault(struct folio *folio, void *shadow);
356 : void workingset_activation(struct folio *folio);
357 :
358 : /* Only track the nodes of mappings with shadow entries */
359 : void workingset_update_node(struct xa_node *node);
360 : extern struct list_lru shadow_nodes;
361 : #define mapping_set_update(xas, mapping) do { \
362 : if (!dax_mapping(mapping) && !shmem_mapping(mapping)) { \
363 : xas_set_update(xas, workingset_update_node); \
364 : xas_set_lru(xas, &shadow_nodes); \
365 : } \
366 : } while (0)
367 :
368 : /* linux/mm/page_alloc.c */
369 : extern unsigned long totalreserve_pages;
370 :
371 : /* Definition of global_zone_page_state not available yet */
372 : #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
373 :
374 :
375 : /* linux/mm/swap.c */
376 : void lru_note_cost(struct lruvec *lruvec, bool file,
377 : unsigned int nr_io, unsigned int nr_rotated);
378 : void lru_note_cost_refault(struct folio *);
379 : void folio_add_lru(struct folio *);
380 : void folio_add_lru_vma(struct folio *, struct vm_area_struct *);
381 : void mark_page_accessed(struct page *);
382 : void folio_mark_accessed(struct folio *);
383 :
384 : extern atomic_t lru_disable_count;
385 :
386 : static inline bool lru_cache_disabled(void)
387 : {
388 0 : return atomic_read(&lru_disable_count);
389 : }
390 :
391 : static inline void lru_cache_enable(void)
392 : {
393 : atomic_dec(&lru_disable_count);
394 : }
395 :
396 : extern void lru_cache_disable(void);
397 : extern void lru_add_drain(void);
398 : extern void lru_add_drain_cpu(int cpu);
399 : extern void lru_add_drain_cpu_zone(struct zone *zone);
400 : extern void lru_add_drain_all(void);
401 : void folio_deactivate(struct folio *folio);
402 : void folio_mark_lazyfree(struct folio *folio);
403 : extern void swap_setup(void);
404 :
405 : extern void lru_cache_add_inactive_or_unevictable(struct page *page,
406 : struct vm_area_struct *vma);
407 :
408 : /* linux/mm/vmscan.c */
409 : extern unsigned long zone_reclaimable_pages(struct zone *zone);
410 : extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
411 : gfp_t gfp_mask, nodemask_t *mask);
412 :
413 : #define MEMCG_RECLAIM_MAY_SWAP (1 << 1)
414 : #define MEMCG_RECLAIM_PROACTIVE (1 << 2)
415 : extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
416 : unsigned long nr_pages,
417 : gfp_t gfp_mask,
418 : unsigned int reclaim_options);
419 : extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
420 : gfp_t gfp_mask, bool noswap,
421 : pg_data_t *pgdat,
422 : unsigned long *nr_scanned);
423 : extern unsigned long shrink_all_memory(unsigned long nr_pages);
424 : extern int vm_swappiness;
425 : long remove_mapping(struct address_space *mapping, struct folio *folio);
426 :
427 : #ifdef CONFIG_NUMA
428 : extern int node_reclaim_mode;
429 : extern int sysctl_min_unmapped_ratio;
430 : extern int sysctl_min_slab_ratio;
431 : #else
432 : #define node_reclaim_mode 0
433 : #endif
434 :
435 : static inline bool node_reclaim_enabled(void)
436 : {
437 : /* Is any node_reclaim_mode bit set? */
438 : return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP);
439 : }
440 :
441 : void check_move_unevictable_folios(struct folio_batch *fbatch);
442 :
443 : extern void __meminit kswapd_run(int nid);
444 : extern void __meminit kswapd_stop(int nid);
445 :
446 : #ifdef CONFIG_SWAP
447 :
448 : int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
449 : unsigned long nr_pages, sector_t start_block);
450 : int generic_swapfile_activate(struct swap_info_struct *, struct file *,
451 : sector_t *);
452 :
453 : static inline unsigned long total_swapcache_pages(void)
454 : {
455 0 : return global_node_page_state(NR_SWAPCACHE);
456 : }
457 :
458 : extern void free_swap_cache(struct page *page);
459 : extern void free_page_and_swap_cache(struct page *);
460 : extern void free_pages_and_swap_cache(struct encoded_page **, int);
461 : /* linux/mm/swapfile.c */
462 : extern atomic_long_t nr_swap_pages;
463 : extern long total_swap_pages;
464 : extern atomic_t nr_rotate_swap;
465 : extern bool has_usable_swap(void);
466 :
467 : /* Swap 50% full? Release swapcache more aggressively.. */
468 : static inline bool vm_swap_full(void)
469 : {
470 0 : return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
471 : }
472 :
473 : static inline long get_nr_swap_pages(void)
474 : {
475 0 : return atomic_long_read(&nr_swap_pages);
476 : }
477 :
478 : extern void si_swapinfo(struct sysinfo *);
479 : swp_entry_t folio_alloc_swap(struct folio *folio);
480 : bool folio_free_swap(struct folio *folio);
481 : void put_swap_folio(struct folio *folio, swp_entry_t entry);
482 : extern swp_entry_t get_swap_page_of_type(int);
483 : extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size);
484 : extern int add_swap_count_continuation(swp_entry_t, gfp_t);
485 : extern void swap_shmem_alloc(swp_entry_t);
486 : extern int swap_duplicate(swp_entry_t);
487 : extern int swapcache_prepare(swp_entry_t);
488 : extern void swap_free(swp_entry_t);
489 : extern void swapcache_free_entries(swp_entry_t *entries, int n);
490 : extern int free_swap_and_cache(swp_entry_t);
491 : int swap_type_of(dev_t device, sector_t offset);
492 : int find_first_swap(dev_t *device);
493 : extern unsigned int count_swap_pages(int, int);
494 : extern sector_t swapdev_block(int, pgoff_t);
495 : extern int __swap_count(swp_entry_t entry);
496 : extern int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry);
497 : extern int swp_swapcount(swp_entry_t entry);
498 : extern struct swap_info_struct *page_swap_info(struct page *);
499 : extern struct swap_info_struct *swp_swap_info(swp_entry_t entry);
500 : struct backing_dev_info;
501 : extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
502 : extern void exit_swap_address_space(unsigned int type);
503 : extern struct swap_info_struct *get_swap_device(swp_entry_t entry);
504 : sector_t swap_page_sector(struct page *page);
505 :
506 : static inline void put_swap_device(struct swap_info_struct *si)
507 : {
508 0 : percpu_ref_put(&si->users);
509 : }
510 :
511 : #else /* CONFIG_SWAP */
512 : static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry)
513 : {
514 : return NULL;
515 : }
516 :
517 : static inline struct swap_info_struct *get_swap_device(swp_entry_t entry)
518 : {
519 : return NULL;
520 : }
521 :
522 : static inline void put_swap_device(struct swap_info_struct *si)
523 : {
524 : }
525 :
526 : #define get_nr_swap_pages() 0L
527 : #define total_swap_pages 0L
528 : #define total_swapcache_pages() 0UL
529 : #define vm_swap_full() 0
530 :
531 : #define si_swapinfo(val) \
532 : do { (val)->freeswap = (val)->totalswap = 0; } while (0)
533 : /* only sparc can not include linux/pagemap.h in this file
534 : * so leave put_page and release_pages undeclared... */
535 : #define free_page_and_swap_cache(page) \
536 : put_page(page)
537 : #define free_pages_and_swap_cache(pages, nr) \
538 : release_pages((pages), (nr));
539 :
540 : /* used to sanity check ptes in zap_pte_range when CONFIG_SWAP=0 */
541 : #define free_swap_and_cache(e) is_pfn_swap_entry(e)
542 :
543 : static inline void free_swap_cache(struct page *page)
544 : {
545 : }
546 :
547 : static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
548 : {
549 : return 0;
550 : }
551 :
552 : static inline void swap_shmem_alloc(swp_entry_t swp)
553 : {
554 : }
555 :
556 : static inline int swap_duplicate(swp_entry_t swp)
557 : {
558 : return 0;
559 : }
560 :
561 : static inline void swap_free(swp_entry_t swp)
562 : {
563 : }
564 :
565 : static inline void put_swap_folio(struct folio *folio, swp_entry_t swp)
566 : {
567 : }
568 :
569 : static inline int __swap_count(swp_entry_t entry)
570 : {
571 : return 0;
572 : }
573 :
574 : static inline int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry)
575 : {
576 : return 0;
577 : }
578 :
579 : static inline int swp_swapcount(swp_entry_t entry)
580 : {
581 : return 0;
582 : }
583 :
584 : static inline swp_entry_t folio_alloc_swap(struct folio *folio)
585 : {
586 : swp_entry_t entry;
587 : entry.val = 0;
588 : return entry;
589 : }
590 :
591 : static inline bool folio_free_swap(struct folio *folio)
592 : {
593 : return false;
594 : }
595 :
596 : static inline int add_swap_extent(struct swap_info_struct *sis,
597 : unsigned long start_page,
598 : unsigned long nr_pages, sector_t start_block)
599 : {
600 : return -EINVAL;
601 : }
602 : #endif /* CONFIG_SWAP */
603 :
604 : #ifdef CONFIG_THP_SWAP
605 : extern int split_swap_cluster(swp_entry_t entry);
606 : #else
607 : static inline int split_swap_cluster(swp_entry_t entry)
608 : {
609 : return 0;
610 : }
611 : #endif
612 :
613 : #ifdef CONFIG_MEMCG
614 : static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
615 : {
616 : /* Cgroup2 doesn't have per-cgroup swappiness */
617 : if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
618 : return READ_ONCE(vm_swappiness);
619 :
620 : /* root ? */
621 : if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg))
622 : return READ_ONCE(vm_swappiness);
623 :
624 : return READ_ONCE(memcg->swappiness);
625 : }
626 : #else
627 : static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
628 : {
629 0 : return READ_ONCE(vm_swappiness);
630 : }
631 : #endif
632 :
633 : #ifdef CONFIG_ZSWAP
634 : extern u64 zswap_pool_total_size;
635 : extern atomic_t zswap_stored_pages;
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);
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
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);
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);
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
674 : static inline void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry)
675 : {
676 : }
677 :
678 : static inline int mem_cgroup_try_charge_swap(struct folio *folio,
679 : swp_entry_t entry)
680 : {
681 : return 0;
682 : }
683 :
684 : static inline void mem_cgroup_uncharge_swap(swp_entry_t entry,
685 : unsigned int nr_pages)
686 : {
687 : }
688 :
689 : static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
690 : {
691 : return get_nr_swap_pages();
692 : }
693 :
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 */
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