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/atomic.h>
14 : #include <linux/page-flags.h>
15 : #include <asm/page.h>
16 :
17 : struct notifier_block;
18 :
19 : struct bio;
20 :
21 : struct pagevec;
22 :
23 : #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
24 : #define SWAP_FLAG_PRIO_MASK 0x7fff
25 : #define SWAP_FLAG_PRIO_SHIFT 0
26 : #define SWAP_FLAG_DISCARD 0x10000 /* enable discard for swap */
27 : #define SWAP_FLAG_DISCARD_ONCE 0x20000 /* discard swap area at swapon-time */
28 : #define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */
29 :
30 : #define SWAP_FLAGS_VALID (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \
31 : SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \
32 : SWAP_FLAG_DISCARD_PAGES)
33 : #define SWAP_BATCH 64
34 :
35 0 : static inline int current_is_kswapd(void)
36 : {
37 0 : return current->flags & PF_KSWAPD;
38 : }
39 :
40 : /*
41 : * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
42 : * be swapped to. The swap type and the offset into that swap type are
43 : * encoded into pte's and into pgoff_t's in the swapcache. Using five bits
44 : * for the type means that the maximum number of swapcache pages is 27 bits
45 : * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
46 : * the type/offset into the pte as 5/27 as well.
47 : */
48 : #define MAX_SWAPFILES_SHIFT 5
49 :
50 : /*
51 : * Use some of the swap files numbers for other purposes. This
52 : * is a convenient way to hook into the VM to trigger special
53 : * actions on faults.
54 : */
55 :
56 : /*
57 : * Unaddressable device memory support. See include/linux/hmm.h and
58 : * Documentation/vm/hmm.rst. Short description is we need struct pages for
59 : * device memory that is unaddressable (inaccessible) by CPU, so that we can
60 : * migrate part of a process memory to device memory.
61 : *
62 : * When a page is migrated from CPU to device, we set the CPU page table entry
63 : * to a special SWP_DEVICE_* entry.
64 : */
65 : #ifdef CONFIG_DEVICE_PRIVATE
66 : #define SWP_DEVICE_NUM 2
67 : #define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM)
68 : #define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1)
69 : #else
70 : #define SWP_DEVICE_NUM 0
71 : #endif
72 :
73 : /*
74 : * NUMA node memory migration support
75 : */
76 : #ifdef CONFIG_MIGRATION
77 : #define SWP_MIGRATION_NUM 2
78 : #define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
79 : #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
80 : #else
81 : #define SWP_MIGRATION_NUM 0
82 : #endif
83 :
84 : /*
85 : * Handling of hardware poisoned pages with memory corruption.
86 : */
87 : #ifdef CONFIG_MEMORY_FAILURE
88 : #define SWP_HWPOISON_NUM 1
89 : #define SWP_HWPOISON MAX_SWAPFILES
90 : #else
91 : #define SWP_HWPOISON_NUM 0
92 : #endif
93 :
94 : #define MAX_SWAPFILES \
95 : ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \
96 : SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)
97 :
98 : /*
99 : * Magic header for a swap area. The first part of the union is
100 : * what the swap magic looks like for the old (limited to 128MB)
101 : * swap area format, the second part of the union adds - in the
102 : * old reserved area - some extra information. Note that the first
103 : * kilobyte is reserved for boot loader or disk label stuff...
104 : *
105 : * Having the magic at the end of the PAGE_SIZE makes detecting swap
106 : * areas somewhat tricky on machines that support multiple page sizes.
107 : * For 2.5 we'll probably want to move the magic to just beyond the
108 : * bootbits...
109 : */
110 : union swap_header {
111 : struct {
112 : char reserved[PAGE_SIZE - 10];
113 : char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
114 : } magic;
115 : struct {
116 : char bootbits[1024]; /* Space for disklabel etc. */
117 : __u32 version;
118 : __u32 last_page;
119 : __u32 nr_badpages;
120 : unsigned char sws_uuid[16];
121 : unsigned char sws_volume[16];
122 : __u32 padding[117];
123 : __u32 badpages[1];
124 : } info;
125 : };
126 :
127 : /*
128 : * current->reclaim_state points to one of these when a task is running
129 : * memory reclaim
130 : */
131 : struct reclaim_state {
132 : unsigned long reclaimed_slab;
133 : };
134 :
135 : #ifdef __KERNEL__
136 :
137 : struct address_space;
138 : struct sysinfo;
139 : struct writeback_control;
140 : struct zone;
141 :
142 : /*
143 : * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
144 : * disk blocks. A list of swap extents maps the entire swapfile. (Where the
145 : * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
146 : * from setup, they're handled identically.
147 : *
148 : * We always assume that blocks are of size PAGE_SIZE.
149 : */
150 : struct swap_extent {
151 : struct rb_node rb_node;
152 : pgoff_t start_page;
153 : pgoff_t nr_pages;
154 : sector_t start_block;
155 : };
156 :
157 : /*
158 : * Max bad pages in the new format..
159 : */
160 : #define MAX_SWAP_BADPAGES \
161 : ((offsetof(union swap_header, magic.magic) - \
162 : offsetof(union swap_header, info.badpages)) / sizeof(int))
163 :
164 : enum {
165 : SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
166 : SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
167 : SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */
168 : SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
169 : SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
170 : SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
171 : SWP_BLKDEV = (1 << 6), /* its a block device */
172 : SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */
173 : SWP_FS_OPS = (1 << 8), /* swapfile operations go through fs */
174 : SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */
175 : SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */
176 : SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */
177 : SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */
178 : SWP_VALID = (1 << 13), /* swap is valid to be operated on? */
179 : /* add others here before... */
180 : SWP_SCANNING = (1 << 14), /* refcount in scan_swap_map */
181 : };
182 :
183 : #define SWAP_CLUSTER_MAX 32UL
184 : #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
185 :
186 : /* Bit flag in swap_map */
187 : #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
188 : #define COUNT_CONTINUED 0x80 /* Flag swap_map continuation for full count */
189 :
190 : /* Special value in first swap_map */
191 : #define SWAP_MAP_MAX 0x3e /* Max count */
192 : #define SWAP_MAP_BAD 0x3f /* Note page is bad */
193 : #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs */
194 :
195 : /* Special value in each swap_map continuation */
196 : #define SWAP_CONT_MAX 0x7f /* Max count */
197 :
198 : /*
199 : * We use this to track usage of a cluster. A cluster is a block of swap disk
200 : * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All
201 : * free clusters are organized into a list. We fetch an entry from the list to
202 : * get a free cluster.
203 : *
204 : * The data field stores next cluster if the cluster is free or cluster usage
205 : * counter otherwise. The flags field determines if a cluster is free. This is
206 : * protected by swap_info_struct.lock.
207 : */
208 : struct swap_cluster_info {
209 : spinlock_t lock; /*
210 : * Protect swap_cluster_info fields
211 : * and swap_info_struct->swap_map
212 : * elements correspond to the swap
213 : * cluster
214 : */
215 : unsigned int data:24;
216 : unsigned int flags:8;
217 : };
218 : #define CLUSTER_FLAG_FREE 1 /* This cluster is free */
219 : #define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */
220 : #define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */
221 :
222 : /*
223 : * We assign a cluster to each CPU, so each CPU can allocate swap entry from
224 : * its own cluster and swapout sequentially. The purpose is to optimize swapout
225 : * throughput.
226 : */
227 : struct percpu_cluster {
228 : struct swap_cluster_info index; /* Current cluster index */
229 : unsigned int next; /* Likely next allocation offset */
230 : };
231 :
232 : struct swap_cluster_list {
233 : struct swap_cluster_info head;
234 : struct swap_cluster_info tail;
235 : };
236 :
237 : /*
238 : * The in-memory structure used to track swap areas.
239 : */
240 : struct swap_info_struct {
241 : unsigned long flags; /* SWP_USED etc: see above */
242 : signed short prio; /* swap priority of this type */
243 : struct plist_node list; /* entry in swap_active_head */
244 : signed char type; /* strange name for an index */
245 : unsigned int max; /* extent of the swap_map */
246 : unsigned char *swap_map; /* vmalloc'ed array of usage counts */
247 : struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
248 : struct swap_cluster_list free_clusters; /* free clusters list */
249 : unsigned int lowest_bit; /* index of first free in swap_map */
250 : unsigned int highest_bit; /* index of last free in swap_map */
251 : unsigned int pages; /* total of usable pages of swap */
252 : unsigned int inuse_pages; /* number of those currently in use */
253 : unsigned int cluster_next; /* likely index for next allocation */
254 : unsigned int cluster_nr; /* countdown to next cluster search */
255 : unsigned int __percpu *cluster_next_cpu; /*percpu index for next allocation */
256 : struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
257 : struct rb_root swap_extent_root;/* root of the swap extent rbtree */
258 : struct block_device *bdev; /* swap device or bdev of swap file */
259 : struct file *swap_file; /* seldom referenced */
260 : unsigned int old_block_size; /* seldom referenced */
261 : #ifdef CONFIG_FRONTSWAP
262 : unsigned long *frontswap_map; /* frontswap in-use, one bit per page */
263 : atomic_t frontswap_pages; /* frontswap pages in-use counter */
264 : #endif
265 : spinlock_t lock; /*
266 : * protect map scan related fields like
267 : * swap_map, lowest_bit, highest_bit,
268 : * inuse_pages, cluster_next,
269 : * cluster_nr, lowest_alloc,
270 : * highest_alloc, free/discard cluster
271 : * list. other fields are only changed
272 : * at swapon/swapoff, so are protected
273 : * by swap_lock. changing flags need
274 : * hold this lock and swap_lock. If
275 : * both locks need hold, hold swap_lock
276 : * first.
277 : */
278 : spinlock_t cont_lock; /*
279 : * protect swap count continuation page
280 : * list.
281 : */
282 : struct work_struct discard_work; /* discard worker */
283 : struct swap_cluster_list discard_clusters; /* discard clusters list */
284 : struct plist_node avail_lists[]; /*
285 : * entries in swap_avail_heads, one
286 : * entry per node.
287 : * Must be last as the number of the
288 : * array is nr_node_ids, which is not
289 : * a fixed value so have to allocate
290 : * dynamically.
291 : * And it has to be an array so that
292 : * plist_for_each_* can work.
293 : */
294 : };
295 :
296 : #ifdef CONFIG_64BIT
297 : #define SWAP_RA_ORDER_CEILING 5
298 : #else
299 : /* Avoid stack overflow, because we need to save part of page table */
300 : #define SWAP_RA_ORDER_CEILING 3
301 : #define SWAP_RA_PTE_CACHE_SIZE (1 << SWAP_RA_ORDER_CEILING)
302 : #endif
303 :
304 : struct vma_swap_readahead {
305 : unsigned short win;
306 : unsigned short offset;
307 : unsigned short nr_pte;
308 : #ifdef CONFIG_64BIT
309 : pte_t *ptes;
310 : #else
311 : pte_t ptes[SWAP_RA_PTE_CACHE_SIZE];
312 : #endif
313 : };
314 :
315 : /* linux/mm/workingset.c */
316 : void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages);
317 : void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg);
318 : void workingset_refault(struct page *page, void *shadow);
319 : void workingset_activation(struct page *page);
320 :
321 : /* Only track the nodes of mappings with shadow entries */
322 : void workingset_update_node(struct xa_node *node);
323 : #define mapping_set_update(xas, mapping) do { \
324 : if (!dax_mapping(mapping) && !shmem_mapping(mapping)) \
325 : xas_set_update(xas, workingset_update_node); \
326 : } while (0)
327 :
328 : /* linux/mm/page_alloc.c */
329 : extern unsigned long totalreserve_pages;
330 : extern unsigned long nr_free_buffer_pages(void);
331 :
332 : /* Definition of global_zone_page_state not available yet */
333 : #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
334 :
335 :
336 : /* linux/mm/swap.c */
337 : extern void lru_note_cost(struct lruvec *lruvec, bool file,
338 : unsigned int nr_pages);
339 : extern void lru_note_cost_page(struct page *);
340 : extern void lru_cache_add(struct page *);
341 : extern void mark_page_accessed(struct page *);
342 : extern void lru_add_drain(void);
343 : extern void lru_add_drain_cpu(int cpu);
344 : extern void lru_add_drain_cpu_zone(struct zone *zone);
345 : extern void lru_add_drain_all(void);
346 : extern void rotate_reclaimable_page(struct page *page);
347 : extern void deactivate_file_page(struct page *page);
348 : extern void deactivate_page(struct page *page);
349 : extern void mark_page_lazyfree(struct page *page);
350 : extern void swap_setup(void);
351 :
352 : extern void lru_cache_add_inactive_or_unevictable(struct page *page,
353 : struct vm_area_struct *vma);
354 :
355 : /* linux/mm/vmscan.c */
356 : extern unsigned long zone_reclaimable_pages(struct zone *zone);
357 : extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
358 : gfp_t gfp_mask, nodemask_t *mask);
359 : extern bool __isolate_lru_page_prepare(struct page *page, isolate_mode_t mode);
360 : extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
361 : unsigned long nr_pages,
362 : gfp_t gfp_mask,
363 : bool may_swap);
364 : extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
365 : gfp_t gfp_mask, bool noswap,
366 : pg_data_t *pgdat,
367 : unsigned long *nr_scanned);
368 : extern unsigned long shrink_all_memory(unsigned long nr_pages);
369 : extern int vm_swappiness;
370 : extern int remove_mapping(struct address_space *mapping, struct page *page);
371 :
372 : extern unsigned long reclaim_pages(struct list_head *page_list);
373 : #ifdef CONFIG_NUMA
374 : extern int node_reclaim_mode;
375 : extern int sysctl_min_unmapped_ratio;
376 : extern int sysctl_min_slab_ratio;
377 : #else
378 : #define node_reclaim_mode 0
379 : #endif
380 :
381 : extern void check_move_unevictable_pages(struct pagevec *pvec);
382 :
383 : extern int kswapd_run(int nid);
384 : extern void kswapd_stop(int nid);
385 :
386 : #ifdef CONFIG_SWAP
387 :
388 : #include <linux/blk_types.h> /* for bio_end_io_t */
389 :
390 : /* linux/mm/page_io.c */
391 : extern int swap_readpage(struct page *page, bool do_poll);
392 : extern int swap_writepage(struct page *page, struct writeback_control *wbc);
393 : extern void end_swap_bio_write(struct bio *bio);
394 : extern int __swap_writepage(struct page *page, struct writeback_control *wbc,
395 : bio_end_io_t end_write_func);
396 : extern int swap_set_page_dirty(struct page *page);
397 :
398 : int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
399 : unsigned long nr_pages, sector_t start_block);
400 : int generic_swapfile_activate(struct swap_info_struct *, struct file *,
401 : sector_t *);
402 :
403 : /* linux/mm/swap_state.c */
404 : /* One swap address space for each 64M swap space */
405 : #define SWAP_ADDRESS_SPACE_SHIFT 14
406 : #define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT)
407 : extern struct address_space *swapper_spaces[];
408 : #define swap_address_space(entry) \
409 : (&swapper_spaces[swp_type(entry)][swp_offset(entry) \
410 : >> SWAP_ADDRESS_SPACE_SHIFT])
411 : static inline unsigned long total_swapcache_pages(void)
412 : {
413 : return global_node_page_state(NR_SWAPCACHE);
414 : }
415 :
416 : extern void show_swap_cache_info(void);
417 : extern int add_to_swap(struct page *page);
418 : extern void *get_shadow_from_swap_cache(swp_entry_t entry);
419 : extern int add_to_swap_cache(struct page *page, swp_entry_t entry,
420 : gfp_t gfp, void **shadowp);
421 : extern void __delete_from_swap_cache(struct page *page,
422 : swp_entry_t entry, void *shadow);
423 : extern void delete_from_swap_cache(struct page *);
424 : extern void clear_shadow_from_swap_cache(int type, unsigned long begin,
425 : unsigned long end);
426 : extern void free_page_and_swap_cache(struct page *);
427 : extern void free_pages_and_swap_cache(struct page **, int);
428 : extern struct page *lookup_swap_cache(swp_entry_t entry,
429 : struct vm_area_struct *vma,
430 : unsigned long addr);
431 : struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index);
432 : extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
433 : struct vm_area_struct *vma, unsigned long addr,
434 : bool do_poll);
435 : extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t,
436 : struct vm_area_struct *vma, unsigned long addr,
437 : bool *new_page_allocated);
438 : extern struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
439 : struct vm_fault *vmf);
440 : extern struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
441 : struct vm_fault *vmf);
442 :
443 : /* linux/mm/swapfile.c */
444 : extern atomic_long_t nr_swap_pages;
445 : extern long total_swap_pages;
446 : extern atomic_t nr_rotate_swap;
447 : extern bool has_usable_swap(void);
448 :
449 : /* Swap 50% full? Release swapcache more aggressively.. */
450 : static inline bool vm_swap_full(void)
451 : {
452 : return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
453 : }
454 :
455 : static inline long get_nr_swap_pages(void)
456 : {
457 : return atomic_long_read(&nr_swap_pages);
458 : }
459 :
460 : extern void si_swapinfo(struct sysinfo *);
461 : extern swp_entry_t get_swap_page(struct page *page);
462 : extern void put_swap_page(struct page *page, swp_entry_t entry);
463 : extern swp_entry_t get_swap_page_of_type(int);
464 : extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size);
465 : extern int add_swap_count_continuation(swp_entry_t, gfp_t);
466 : extern void swap_shmem_alloc(swp_entry_t);
467 : extern int swap_duplicate(swp_entry_t);
468 : extern int swapcache_prepare(swp_entry_t);
469 : extern void swap_free(swp_entry_t);
470 : extern void swapcache_free_entries(swp_entry_t *entries, int n);
471 : extern int free_swap_and_cache(swp_entry_t);
472 : int swap_type_of(dev_t device, sector_t offset);
473 : int find_first_swap(dev_t *device);
474 : extern unsigned int count_swap_pages(int, int);
475 : extern sector_t swapdev_block(int, pgoff_t);
476 : extern int page_swapcount(struct page *);
477 : extern int __swap_count(swp_entry_t entry);
478 : extern int __swp_swapcount(swp_entry_t entry);
479 : extern int swp_swapcount(swp_entry_t entry);
480 : extern struct swap_info_struct *page_swap_info(struct page *);
481 : extern struct swap_info_struct *swp_swap_info(swp_entry_t entry);
482 : extern bool reuse_swap_page(struct page *, int *);
483 : extern int try_to_free_swap(struct page *);
484 : struct backing_dev_info;
485 : extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
486 : extern void exit_swap_address_space(unsigned int type);
487 : extern struct swap_info_struct *get_swap_device(swp_entry_t entry);
488 : sector_t swap_page_sector(struct page *page);
489 :
490 : static inline void put_swap_device(struct swap_info_struct *si)
491 : {
492 : rcu_read_unlock();
493 : }
494 :
495 : #else /* CONFIG_SWAP */
496 :
497 : static inline int swap_readpage(struct page *page, bool do_poll)
498 : {
499 : return 0;
500 : }
501 :
502 0 : static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry)
503 : {
504 0 : return NULL;
505 : }
506 :
507 : #define swap_address_space(entry) (NULL)
508 : #define get_nr_swap_pages() 0L
509 : #define total_swap_pages 0L
510 : #define total_swapcache_pages() 0UL
511 : #define vm_swap_full() 0
512 :
513 : #define si_swapinfo(val) \
514 : do { (val)->freeswap = (val)->totalswap = 0; } while (0)
515 : /* only sparc can not include linux/pagemap.h in this file
516 : * so leave put_page and release_pages undeclared... */
517 : #define free_page_and_swap_cache(page) \
518 : put_page(page)
519 : #define free_pages_and_swap_cache(pages, nr) \
520 : release_pages((pages), (nr));
521 :
522 0 : static inline void show_swap_cache_info(void)
523 : {
524 0 : }
525 :
526 : #define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
527 : #define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
528 :
529 : static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
530 : {
531 : return 0;
532 : }
533 :
534 : static inline void swap_shmem_alloc(swp_entry_t swp)
535 : {
536 : }
537 :
538 0 : static inline int swap_duplicate(swp_entry_t swp)
539 : {
540 0 : return 0;
541 : }
542 :
543 : static inline void swap_free(swp_entry_t swp)
544 : {
545 : }
546 :
547 : static inline void put_swap_page(struct page *page, swp_entry_t swp)
548 : {
549 : }
550 :
551 0 : static inline struct page *swap_cluster_readahead(swp_entry_t entry,
552 : gfp_t gfp_mask, struct vm_fault *vmf)
553 : {
554 0 : return NULL;
555 : }
556 :
557 0 : static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
558 : struct vm_fault *vmf)
559 : {
560 0 : return NULL;
561 : }
562 :
563 : static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
564 : {
565 : return 0;
566 : }
567 :
568 0 : static inline struct page *lookup_swap_cache(swp_entry_t swp,
569 : struct vm_area_struct *vma,
570 : unsigned long addr)
571 : {
572 0 : return NULL;
573 : }
574 :
575 : static inline
576 0 : struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index)
577 : {
578 0 : return find_get_page(mapping, index);
579 : }
580 :
581 0 : static inline int add_to_swap(struct page *page)
582 : {
583 0 : return 0;
584 : }
585 :
586 : static inline void *get_shadow_from_swap_cache(swp_entry_t entry)
587 : {
588 : return NULL;
589 : }
590 :
591 : static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
592 : gfp_t gfp_mask, void **shadowp)
593 : {
594 : return -1;
595 : }
596 :
597 : static inline void __delete_from_swap_cache(struct page *page,
598 : swp_entry_t entry, void *shadow)
599 : {
600 : }
601 :
602 : static inline void delete_from_swap_cache(struct page *page)
603 : {
604 : }
605 :
606 : static inline void clear_shadow_from_swap_cache(int type, unsigned long begin,
607 : unsigned long end)
608 : {
609 : }
610 :
611 : static inline int page_swapcount(struct page *page)
612 : {
613 : return 0;
614 : }
615 :
616 : static inline int __swap_count(swp_entry_t entry)
617 : {
618 : return 0;
619 : }
620 :
621 : static inline int __swp_swapcount(swp_entry_t entry)
622 : {
623 : return 0;
624 : }
625 :
626 : static inline int swp_swapcount(swp_entry_t entry)
627 : {
628 : return 0;
629 : }
630 :
631 : #define reuse_swap_page(page, total_map_swapcount) \
632 : (page_trans_huge_mapcount(page, total_map_swapcount) == 1)
633 :
634 : static inline int try_to_free_swap(struct page *page)
635 : {
636 : return 0;
637 : }
638 :
639 : static inline swp_entry_t get_swap_page(struct page *page)
640 : {
641 : swp_entry_t entry;
642 : entry.val = 0;
643 : return entry;
644 : }
645 :
646 : #endif /* CONFIG_SWAP */
647 :
648 : #ifdef CONFIG_THP_SWAP
649 : extern int split_swap_cluster(swp_entry_t entry);
650 : #else
651 : static inline int split_swap_cluster(swp_entry_t entry)
652 : {
653 : return 0;
654 : }
655 : #endif
656 :
657 : #ifdef CONFIG_MEMCG
658 : static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
659 : {
660 : /* Cgroup2 doesn't have per-cgroup swappiness */
661 : if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
662 : return vm_swappiness;
663 :
664 : /* root ? */
665 : if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg))
666 : return vm_swappiness;
667 :
668 : return memcg->swappiness;
669 : }
670 : #else
671 0 : static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
672 : {
673 0 : return vm_swappiness;
674 : }
675 : #endif
676 :
677 : #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
678 : extern void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask);
679 : #else
680 70453 : static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
681 : {
682 70453 : }
683 : #endif
684 :
685 : #ifdef CONFIG_MEMCG_SWAP
686 : extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);
687 : extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);
688 : extern void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
689 : extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
690 : extern bool mem_cgroup_swap_full(struct page *page);
691 : #else
692 : static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
693 : {
694 : }
695 :
696 : static inline int mem_cgroup_try_charge_swap(struct page *page,
697 : swp_entry_t entry)
698 : {
699 : return 0;
700 : }
701 :
702 : static inline void mem_cgroup_uncharge_swap(swp_entry_t entry,
703 : unsigned int nr_pages)
704 : {
705 : }
706 :
707 0 : static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
708 : {
709 0 : return get_nr_swap_pages();
710 : }
711 :
712 : static inline bool mem_cgroup_swap_full(struct page *page)
713 : {
714 : return vm_swap_full();
715 : }
716 : #endif
717 :
718 : #endif /* __KERNEL__*/
719 : #endif /* _LINUX_SWAP_H */
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