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 : unsigned long reclaimed_slab;
157 : #ifdef CONFIG_LRU_GEN
158 : /* per-thread mm walk data */
159 : struct lru_gen_mm_walk *mm_walk;
160 : #endif
161 : };
162 :
163 : #ifdef __KERNEL__
164 :
165 : struct address_space;
166 : struct sysinfo;
167 : struct writeback_control;
168 : struct zone;
169 :
170 : /*
171 : * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
172 : * disk blocks. A rbtree of swap extents maps the entire swapfile (Where the
173 : * term `swapfile' refers to either a blockdevice or an IS_REG file). Apart
174 : * from setup, they're handled identically.
175 : *
176 : * We always assume that blocks are of size PAGE_SIZE.
177 : */
178 : struct swap_extent {
179 : struct rb_node rb_node;
180 : pgoff_t start_page;
181 : pgoff_t nr_pages;
182 : sector_t start_block;
183 : };
184 :
185 : /*
186 : * Max bad pages in the new format..
187 : */
188 : #define MAX_SWAP_BADPAGES \
189 : ((offsetof(union swap_header, magic.magic) - \
190 : offsetof(union swap_header, info.badpages)) / sizeof(int))
191 :
192 : enum {
193 : SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
194 : SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
195 : SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */
196 : SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
197 : SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
198 : SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
199 : SWP_BLKDEV = (1 << 6), /* its a block device */
200 : SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */
201 : SWP_FS_OPS = (1 << 8), /* swapfile operations go through fs */
202 : SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */
203 : SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */
204 : SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */
205 : SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */
206 : /* add others here before... */
207 : SWP_SCANNING = (1 << 14), /* refcount in scan_swap_map */
208 : };
209 :
210 : #define SWAP_CLUSTER_MAX 32UL
211 : #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
212 :
213 : /* Bit flag in swap_map */
214 : #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
215 : #define COUNT_CONTINUED 0x80 /* Flag swap_map continuation for full count */
216 :
217 : /* Special value in first swap_map */
218 : #define SWAP_MAP_MAX 0x3e /* Max count */
219 : #define SWAP_MAP_BAD 0x3f /* Note page is bad */
220 : #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs */
221 :
222 : /* Special value in each swap_map continuation */
223 : #define SWAP_CONT_MAX 0x7f /* Max count */
224 :
225 : /*
226 : * We use this to track usage of a cluster. A cluster is a block of swap disk
227 : * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All
228 : * free clusters are organized into a list. We fetch an entry from the list to
229 : * get a free cluster.
230 : *
231 : * The data field stores next cluster if the cluster is free or cluster usage
232 : * counter otherwise. The flags field determines if a cluster is free. This is
233 : * protected by swap_info_struct.lock.
234 : */
235 : struct swap_cluster_info {
236 : spinlock_t lock; /*
237 : * Protect swap_cluster_info fields
238 : * and swap_info_struct->swap_map
239 : * elements correspond to the swap
240 : * cluster
241 : */
242 : unsigned int data:24;
243 : unsigned int flags:8;
244 : };
245 : #define CLUSTER_FLAG_FREE 1 /* This cluster is free */
246 : #define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */
247 : #define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */
248 :
249 : /*
250 : * We assign a cluster to each CPU, so each CPU can allocate swap entry from
251 : * its own cluster and swapout sequentially. The purpose is to optimize swapout
252 : * throughput.
253 : */
254 : struct percpu_cluster {
255 : struct swap_cluster_info index; /* Current cluster index */
256 : unsigned int next; /* Likely next allocation offset */
257 : };
258 :
259 : struct swap_cluster_list {
260 : struct swap_cluster_info head;
261 : struct swap_cluster_info tail;
262 : };
263 :
264 : /*
265 : * The in-memory structure used to track swap areas.
266 : */
267 : struct swap_info_struct {
268 : struct percpu_ref users; /* indicate and keep swap device valid. */
269 : unsigned long flags; /* SWP_USED etc: see above */
270 : signed short prio; /* swap priority of this type */
271 : struct plist_node list; /* entry in swap_active_head */
272 : signed char type; /* strange name for an index */
273 : unsigned int max; /* extent of the swap_map */
274 : unsigned char *swap_map; /* vmalloc'ed array of usage counts */
275 : struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
276 : struct swap_cluster_list free_clusters; /* free clusters list */
277 : unsigned int lowest_bit; /* index of first free in swap_map */
278 : unsigned int highest_bit; /* index of last free in swap_map */
279 : unsigned int pages; /* total of usable pages of swap */
280 : unsigned int inuse_pages; /* number of those currently in use */
281 : unsigned int cluster_next; /* likely index for next allocation */
282 : unsigned int cluster_nr; /* countdown to next cluster search */
283 : unsigned int __percpu *cluster_next_cpu; /*percpu index for next allocation */
284 : struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
285 : struct rb_root swap_extent_root;/* root of the swap extent rbtree */
286 : struct block_device *bdev; /* swap device or bdev of swap file */
287 : struct file *swap_file; /* seldom referenced */
288 : unsigned int old_block_size; /* seldom referenced */
289 : struct completion comp; /* seldom referenced */
290 : #ifdef CONFIG_FRONTSWAP
291 : unsigned long *frontswap_map; /* frontswap in-use, one bit per page */
292 : atomic_t frontswap_pages; /* frontswap pages in-use counter */
293 : #endif
294 : spinlock_t lock; /*
295 : * protect map scan related fields like
296 : * swap_map, lowest_bit, highest_bit,
297 : * inuse_pages, cluster_next,
298 : * cluster_nr, lowest_alloc,
299 : * highest_alloc, free/discard cluster
300 : * list. other fields are only changed
301 : * at swapon/swapoff, so are protected
302 : * by swap_lock. changing flags need
303 : * hold this lock and swap_lock. If
304 : * both locks need hold, hold swap_lock
305 : * first.
306 : */
307 : spinlock_t cont_lock; /*
308 : * protect swap count continuation page
309 : * list.
310 : */
311 : struct work_struct discard_work; /* discard worker */
312 : struct swap_cluster_list discard_clusters; /* discard clusters list */
313 : struct plist_node avail_lists[]; /*
314 : * entries in swap_avail_heads, one
315 : * entry per node.
316 : * Must be last as the number of the
317 : * array is nr_node_ids, which is not
318 : * a fixed value so have to allocate
319 : * dynamically.
320 : * And it has to be an array so that
321 : * plist_for_each_* can work.
322 : */
323 : };
324 :
325 : #ifdef CONFIG_64BIT
326 : #define SWAP_RA_ORDER_CEILING 5
327 : #else
328 : /* Avoid stack overflow, because we need to save part of page table */
329 : #define SWAP_RA_ORDER_CEILING 3
330 : #define SWAP_RA_PTE_CACHE_SIZE (1 << SWAP_RA_ORDER_CEILING)
331 : #endif
332 :
333 : struct vma_swap_readahead {
334 : unsigned short win;
335 : unsigned short offset;
336 : unsigned short nr_pte;
337 : #ifdef CONFIG_64BIT
338 : pte_t *ptes;
339 : #else
340 : pte_t ptes[SWAP_RA_PTE_CACHE_SIZE];
341 : #endif
342 : };
343 :
344 : static inline swp_entry_t folio_swap_entry(struct folio *folio)
345 : {
346 0 : swp_entry_t entry = { .val = page_private(&folio->page) };
347 : return entry;
348 : }
349 :
350 : static inline void folio_set_swap_entry(struct folio *folio, swp_entry_t entry)
351 : {
352 0 : folio->private = (void *)entry.val;
353 : }
354 :
355 : /* linux/mm/workingset.c */
356 : void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages);
357 : void *workingset_eviction(struct folio *folio, struct mem_cgroup *target_memcg);
358 : void workingset_refault(struct folio *folio, void *shadow);
359 : void workingset_activation(struct folio *folio);
360 :
361 : /* Only track the nodes of mappings with shadow entries */
362 : void workingset_update_node(struct xa_node *node);
363 : extern struct list_lru shadow_nodes;
364 : #define mapping_set_update(xas, mapping) do { \
365 : if (!dax_mapping(mapping) && !shmem_mapping(mapping)) { \
366 : xas_set_update(xas, workingset_update_node); \
367 : xas_set_lru(xas, &shadow_nodes); \
368 : } \
369 : } while (0)
370 :
371 : /* linux/mm/page_alloc.c */
372 : extern unsigned long totalreserve_pages;
373 :
374 : /* Definition of global_zone_page_state not available yet */
375 : #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
376 :
377 :
378 : /* linux/mm/swap.c */
379 : void lru_note_cost(struct lruvec *lruvec, bool file,
380 : unsigned int nr_io, unsigned int nr_rotated);
381 : void lru_note_cost_refault(struct folio *);
382 : void folio_add_lru(struct folio *);
383 : void folio_add_lru_vma(struct folio *, struct vm_area_struct *);
384 : void mark_page_accessed(struct page *);
385 : void folio_mark_accessed(struct folio *);
386 :
387 : extern atomic_t lru_disable_count;
388 :
389 : static inline bool lru_cache_disabled(void)
390 : {
391 0 : return atomic_read(&lru_disable_count);
392 : }
393 :
394 : static inline void lru_cache_enable(void)
395 : {
396 : atomic_dec(&lru_disable_count);
397 : }
398 :
399 : extern void lru_cache_disable(void);
400 : extern void lru_add_drain(void);
401 : extern void lru_add_drain_cpu(int cpu);
402 : extern void lru_add_drain_cpu_zone(struct zone *zone);
403 : extern void lru_add_drain_all(void);
404 : void folio_deactivate(struct folio *folio);
405 : void folio_mark_lazyfree(struct folio *folio);
406 : extern void swap_setup(void);
407 :
408 : extern void lru_cache_add_inactive_or_unevictable(struct page *page,
409 : struct vm_area_struct *vma);
410 :
411 : /* linux/mm/vmscan.c */
412 : extern unsigned long zone_reclaimable_pages(struct zone *zone);
413 : extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
414 : gfp_t gfp_mask, nodemask_t *mask);
415 :
416 : #define MEMCG_RECLAIM_MAY_SWAP (1 << 1)
417 : #define MEMCG_RECLAIM_PROACTIVE (1 << 2)
418 : extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
419 : unsigned long nr_pages,
420 : gfp_t gfp_mask,
421 : unsigned int reclaim_options);
422 : extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
423 : gfp_t gfp_mask, bool noswap,
424 : pg_data_t *pgdat,
425 : unsigned long *nr_scanned);
426 : extern unsigned long shrink_all_memory(unsigned long nr_pages);
427 : extern int vm_swappiness;
428 : long remove_mapping(struct address_space *mapping, struct folio *folio);
429 :
430 : extern unsigned long reclaim_pages(struct list_head *page_list);
431 : #ifdef CONFIG_NUMA
432 : extern int node_reclaim_mode;
433 : extern int sysctl_min_unmapped_ratio;
434 : extern int sysctl_min_slab_ratio;
435 : #else
436 : #define node_reclaim_mode 0
437 : #endif
438 :
439 : static inline bool node_reclaim_enabled(void)
440 : {
441 : /* Is any node_reclaim_mode bit set? */
442 : return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP);
443 : }
444 :
445 : void check_move_unevictable_folios(struct folio_batch *fbatch);
446 : void check_move_unevictable_pages(struct pagevec *pvec);
447 :
448 : extern void kswapd_run(int nid);
449 : extern void kswapd_stop(int nid);
450 :
451 : #ifdef CONFIG_SWAP
452 :
453 : int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
454 : unsigned long nr_pages, sector_t start_block);
455 : int generic_swapfile_activate(struct swap_info_struct *, struct file *,
456 : sector_t *);
457 :
458 : static inline unsigned long total_swapcache_pages(void)
459 : {
460 0 : return global_node_page_state(NR_SWAPCACHE);
461 : }
462 :
463 : extern void free_swap_cache(struct page *page);
464 : extern void free_page_and_swap_cache(struct page *);
465 : extern void free_pages_and_swap_cache(struct encoded_page **, int);
466 : /* linux/mm/swapfile.c */
467 : extern atomic_long_t nr_swap_pages;
468 : extern long total_swap_pages;
469 : extern atomic_t nr_rotate_swap;
470 : extern bool has_usable_swap(void);
471 :
472 : /* Swap 50% full? Release swapcache more aggressively.. */
473 : static inline bool vm_swap_full(void)
474 : {
475 0 : return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
476 : }
477 :
478 : static inline long get_nr_swap_pages(void)
479 : {
480 0 : return atomic_long_read(&nr_swap_pages);
481 : }
482 :
483 : extern void si_swapinfo(struct sysinfo *);
484 : swp_entry_t folio_alloc_swap(struct folio *folio);
485 : bool folio_free_swap(struct folio *folio);
486 : void put_swap_folio(struct folio *folio, swp_entry_t entry);
487 : extern swp_entry_t get_swap_page_of_type(int);
488 : extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size);
489 : extern int add_swap_count_continuation(swp_entry_t, gfp_t);
490 : extern void swap_shmem_alloc(swp_entry_t);
491 : extern int swap_duplicate(swp_entry_t);
492 : extern int swapcache_prepare(swp_entry_t);
493 : extern void swap_free(swp_entry_t);
494 : extern void swapcache_free_entries(swp_entry_t *entries, int n);
495 : extern int free_swap_and_cache(swp_entry_t);
496 : int swap_type_of(dev_t device, sector_t offset);
497 : int find_first_swap(dev_t *device);
498 : extern unsigned int count_swap_pages(int, int);
499 : extern sector_t swapdev_block(int, pgoff_t);
500 : extern int __swap_count(swp_entry_t entry);
501 : extern int __swp_swapcount(swp_entry_t entry);
502 : extern int swp_swapcount(swp_entry_t entry);
503 : extern struct swap_info_struct *page_swap_info(struct page *);
504 : extern struct swap_info_struct *swp_swap_info(swp_entry_t entry);
505 : struct backing_dev_info;
506 : extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
507 : extern void exit_swap_address_space(unsigned int type);
508 : extern struct swap_info_struct *get_swap_device(swp_entry_t entry);
509 : sector_t swap_page_sector(struct page *page);
510 :
511 : static inline void put_swap_device(struct swap_info_struct *si)
512 : {
513 0 : percpu_ref_put(&si->users);
514 : }
515 :
516 : #else /* CONFIG_SWAP */
517 : static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry)
518 : {
519 : return NULL;
520 : }
521 :
522 : static inline struct swap_info_struct *get_swap_device(swp_entry_t entry)
523 : {
524 : return NULL;
525 : }
526 :
527 : static inline void put_swap_device(struct swap_info_struct *si)
528 : {
529 : }
530 :
531 : #define get_nr_swap_pages() 0L
532 : #define total_swap_pages 0L
533 : #define total_swapcache_pages() 0UL
534 : #define vm_swap_full() 0
535 :
536 : #define si_swapinfo(val) \
537 : do { (val)->freeswap = (val)->totalswap = 0; } while (0)
538 : /* only sparc can not include linux/pagemap.h in this file
539 : * so leave put_page and release_pages undeclared... */
540 : #define free_page_and_swap_cache(page) \
541 : put_page(page)
542 : #define free_pages_and_swap_cache(pages, nr) \
543 : release_pages((pages), (nr));
544 :
545 : /* used to sanity check ptes in zap_pte_range when CONFIG_SWAP=0 */
546 : #define free_swap_and_cache(e) is_pfn_swap_entry(e)
547 :
548 : static inline void free_swap_cache(struct page *page)
549 : {
550 : }
551 :
552 : static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
553 : {
554 : return 0;
555 : }
556 :
557 : static inline void swap_shmem_alloc(swp_entry_t swp)
558 : {
559 : }
560 :
561 : static inline int swap_duplicate(swp_entry_t swp)
562 : {
563 : return 0;
564 : }
565 :
566 : static inline void swap_free(swp_entry_t swp)
567 : {
568 : }
569 :
570 : static inline void put_swap_folio(struct folio *folio, swp_entry_t swp)
571 : {
572 : }
573 :
574 : static inline int __swap_count(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 int swp_swapcount(swp_entry_t entry)
585 : {
586 : return 0;
587 : }
588 :
589 : static inline swp_entry_t folio_alloc_swap(struct folio *folio)
590 : {
591 : swp_entry_t entry;
592 : entry.val = 0;
593 : return entry;
594 : }
595 :
596 : static inline bool folio_free_swap(struct folio *folio)
597 : {
598 : return false;
599 : }
600 :
601 : static inline int add_swap_extent(struct swap_info_struct *sis,
602 : unsigned long start_page,
603 : unsigned long nr_pages, sector_t start_block)
604 : {
605 : return -EINVAL;
606 : }
607 : #endif /* CONFIG_SWAP */
608 :
609 : #ifdef CONFIG_THP_SWAP
610 : extern int split_swap_cluster(swp_entry_t entry);
611 : #else
612 : static inline int split_swap_cluster(swp_entry_t entry)
613 : {
614 : return 0;
615 : }
616 : #endif
617 :
618 : #ifdef CONFIG_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 vm_swappiness;
624 :
625 : /* root ? */
626 : if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg))
627 : return vm_swappiness;
628 :
629 : return memcg->swappiness;
630 : }
631 : #else
632 : static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
633 : {
634 0 : return vm_swappiness;
635 : }
636 : #endif
637 :
638 : #ifdef CONFIG_ZSWAP
639 : extern u64 zswap_pool_total_size;
640 : extern atomic_t zswap_stored_pages;
641 : #endif
642 :
643 : #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
644 : extern void __cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask);
645 : static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
646 : {
647 : if (mem_cgroup_disabled())
648 : return;
649 : __cgroup_throttle_swaprate(page, gfp_mask);
650 : }
651 : #else
652 : static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
653 : {
654 : }
655 : #endif
656 : static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp)
657 : {
658 : cgroup_throttle_swaprate(&folio->page, gfp);
659 : }
660 :
661 : #if defined(CONFIG_MEMCG) && defined(CONFIG_SWAP)
662 : void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry);
663 : int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry);
664 : static inline int mem_cgroup_try_charge_swap(struct folio *folio,
665 : swp_entry_t entry)
666 : {
667 : if (mem_cgroup_disabled())
668 : return 0;
669 : return __mem_cgroup_try_charge_swap(folio, entry);
670 : }
671 :
672 : extern void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
673 : static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
674 : {
675 : if (mem_cgroup_disabled())
676 : return;
677 : __mem_cgroup_uncharge_swap(entry, nr_pages);
678 : }
679 :
680 : extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
681 : extern bool mem_cgroup_swap_full(struct folio *folio);
682 : #else
683 : static inline void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry)
684 : {
685 : }
686 :
687 : static inline int mem_cgroup_try_charge_swap(struct folio *folio,
688 : swp_entry_t entry)
689 : {
690 : return 0;
691 : }
692 :
693 : static inline void mem_cgroup_uncharge_swap(swp_entry_t entry,
694 : unsigned int nr_pages)
695 : {
696 : }
697 :
698 : static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
699 : {
700 : return get_nr_swap_pages();
701 : }
702 :
703 : static inline bool mem_cgroup_swap_full(struct folio *folio)
704 : {
705 : return vm_swap_full();
706 : }
707 : #endif
708 :
709 : #endif /* __KERNEL__*/
710 : #endif /* _LINUX_SWAP_H */
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