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