Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
17struct notifier_block;
18
19struct bio;
20
21struct 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
35static inline int current_is_kswapd(void)
36{
37 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 */
110union 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 */
131struct reclaim_state {
132 unsigned long reclaimed_slab;
133};
134
135#ifdef __KERNEL__
136
137struct address_space;
138struct sysinfo;
139struct writeback_control;
140struct 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 */
150struct 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
164enum {
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 = (1 << 8), /* swap file goes 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#define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */
187#define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */
188#define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
189#define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */
190#define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */
191#define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */
192
193/*
194 * We use this to track usage of a cluster. A cluster is a block of swap disk
195 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All
196 * free clusters are organized into a list. We fetch an entry from the list to
197 * get a free cluster.
198 *
199 * The data field stores next cluster if the cluster is free or cluster usage
200 * counter otherwise. The flags field determines if a cluster is free. This is
201 * protected by swap_info_struct.lock.
202 */
203struct swap_cluster_info {
204 spinlock_t lock; /*
205 * Protect swap_cluster_info fields
206 * and swap_info_struct->swap_map
207 * elements correspond to the swap
208 * cluster
209 */
210 unsigned int data:24;
211 unsigned int flags:8;
212};
213#define CLUSTER_FLAG_FREE 1 /* This cluster is free */
214#define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */
215#define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */
216
217/*
218 * We assign a cluster to each CPU, so each CPU can allocate swap entry from
219 * its own cluster and swapout sequentially. The purpose is to optimize swapout
220 * throughput.
221 */
222struct percpu_cluster {
223 struct swap_cluster_info index; /* Current cluster index */
224 unsigned int next; /* Likely next allocation offset */
225};
226
227struct swap_cluster_list {
228 struct swap_cluster_info head;
229 struct swap_cluster_info tail;
230};
231
232/*
233 * The in-memory structure used to track swap areas.
234 */
235struct swap_info_struct {
236 unsigned long flags; /* SWP_USED etc: see above */
237 signed short prio; /* swap priority of this type */
238 struct plist_node list; /* entry in swap_active_head */
239 signed char type; /* strange name for an index */
240 unsigned int max; /* extent of the swap_map */
241 unsigned char *swap_map; /* vmalloc'ed array of usage counts */
242 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
243 struct swap_cluster_list free_clusters; /* free clusters list */
244 unsigned int lowest_bit; /* index of first free in swap_map */
245 unsigned int highest_bit; /* index of last free in swap_map */
246 unsigned int pages; /* total of usable pages of swap */
247 unsigned int inuse_pages; /* number of those currently in use */
248 unsigned int cluster_next; /* likely index for next allocation */
249 unsigned int cluster_nr; /* countdown to next cluster search */
250 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
251 struct rb_root swap_extent_root;/* root of the swap extent rbtree */
252 struct block_device *bdev; /* swap device or bdev of swap file */
253 struct file *swap_file; /* seldom referenced */
254 unsigned int old_block_size; /* seldom referenced */
255#ifdef CONFIG_FRONTSWAP
256 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */
257 atomic_t frontswap_pages; /* frontswap pages in-use counter */
258#endif
259 spinlock_t lock; /*
260 * protect map scan related fields like
261 * swap_map, lowest_bit, highest_bit,
262 * inuse_pages, cluster_next,
263 * cluster_nr, lowest_alloc,
264 * highest_alloc, free/discard cluster
265 * list. other fields are only changed
266 * at swapon/swapoff, so are protected
267 * by swap_lock. changing flags need
268 * hold this lock and swap_lock. If
269 * both locks need hold, hold swap_lock
270 * first.
271 */
272 spinlock_t cont_lock; /*
273 * protect swap count continuation page
274 * list.
275 */
276 struct work_struct discard_work; /* discard worker */
277 struct swap_cluster_list discard_clusters; /* discard clusters list */
278 struct plist_node avail_lists[]; /*
279 * entries in swap_avail_heads, one
280 * entry per node.
281 * Must be last as the number of the
282 * array is nr_node_ids, which is not
283 * a fixed value so have to allocate
284 * dynamically.
285 * And it has to be an array so that
286 * plist_for_each_* can work.
287 */
288};
289
290#ifdef CONFIG_64BIT
291#define SWAP_RA_ORDER_CEILING 5
292#else
293/* Avoid stack overflow, because we need to save part of page table */
294#define SWAP_RA_ORDER_CEILING 3
295#define SWAP_RA_PTE_CACHE_SIZE (1 << SWAP_RA_ORDER_CEILING)
296#endif
297
298struct vma_swap_readahead {
299 unsigned short win;
300 unsigned short offset;
301 unsigned short nr_pte;
302#ifdef CONFIG_64BIT
303 pte_t *ptes;
304#else
305 pte_t ptes[SWAP_RA_PTE_CACHE_SIZE];
306#endif
307};
308
309/* linux/mm/workingset.c */
310void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg);
311void workingset_refault(struct page *page, void *shadow);
312void workingset_activation(struct page *page);
313
314/* Only track the nodes of mappings with shadow entries */
315void workingset_update_node(struct xa_node *node);
316#define mapping_set_update(xas, mapping) do { \
317 if (!dax_mapping(mapping) && !shmem_mapping(mapping)) \
318 xas_set_update(xas, workingset_update_node); \
319} while (0)
320
321/* linux/mm/page_alloc.c */
322extern unsigned long totalreserve_pages;
323extern unsigned long nr_free_buffer_pages(void);
324extern unsigned long nr_free_pagecache_pages(void);
325
326/* Definition of global_zone_page_state not available yet */
327#define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
328
329
330/* linux/mm/swap.c */
331extern void lru_cache_add(struct page *);
332extern void lru_cache_add_anon(struct page *page);
333extern void lru_cache_add_file(struct page *page);
334extern void lru_add_page_tail(struct page *page, struct page *page_tail,
335 struct lruvec *lruvec, struct list_head *head);
336extern void activate_page(struct page *);
337extern void mark_page_accessed(struct page *);
338extern void lru_add_drain(void);
339extern void lru_add_drain_cpu(int cpu);
340extern void lru_add_drain_all(void);
341extern void rotate_reclaimable_page(struct page *page);
342extern void deactivate_file_page(struct page *page);
343extern void deactivate_page(struct page *page);
344extern void mark_page_lazyfree(struct page *page);
345extern void swap_setup(void);
346
347extern void lru_cache_add_active_or_unevictable(struct page *page,
348 struct vm_area_struct *vma);
349
350/* linux/mm/vmscan.c */
351extern unsigned long zone_reclaimable_pages(struct zone *zone);
352extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
353 gfp_t gfp_mask, nodemask_t *mask);
354extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
355extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
356 unsigned long nr_pages,
357 gfp_t gfp_mask,
358 bool may_swap);
359extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
360 gfp_t gfp_mask, bool noswap,
361 pg_data_t *pgdat,
362 unsigned long *nr_scanned);
363extern unsigned long shrink_all_memory(unsigned long nr_pages);
364extern int vm_swappiness;
365extern int remove_mapping(struct address_space *mapping, struct page *page);
366extern unsigned long vm_total_pages;
367
368extern unsigned long reclaim_pages(struct list_head *page_list);
369#ifdef CONFIG_NUMA
370extern int node_reclaim_mode;
371extern int sysctl_min_unmapped_ratio;
372extern int sysctl_min_slab_ratio;
373#else
374#define node_reclaim_mode 0
375#endif
376
377extern void check_move_unevictable_pages(struct pagevec *pvec);
378
379extern int kswapd_run(int nid);
380extern void kswapd_stop(int nid);
381
382#ifdef CONFIG_SWAP
383
384#include <linux/blk_types.h> /* for bio_end_io_t */
385
386/* linux/mm/page_io.c */
387extern int swap_readpage(struct page *page, bool do_poll);
388extern int swap_writepage(struct page *page, struct writeback_control *wbc);
389extern void end_swap_bio_write(struct bio *bio);
390extern int __swap_writepage(struct page *page, struct writeback_control *wbc,
391 bio_end_io_t end_write_func);
392extern int swap_set_page_dirty(struct page *page);
393
394int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
395 unsigned long nr_pages, sector_t start_block);
396int generic_swapfile_activate(struct swap_info_struct *, struct file *,
397 sector_t *);
398
399/* linux/mm/swap_state.c */
400/* One swap address space for each 64M swap space */
401#define SWAP_ADDRESS_SPACE_SHIFT 14
402#define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT)
403extern struct address_space *swapper_spaces[];
404#define swap_address_space(entry) \
405 (&swapper_spaces[swp_type(entry)][swp_offset(entry) \
406 >> SWAP_ADDRESS_SPACE_SHIFT])
407extern unsigned long total_swapcache_pages(void);
408extern void show_swap_cache_info(void);
409extern int add_to_swap(struct page *page);
410extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
411extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
412extern void __delete_from_swap_cache(struct page *, swp_entry_t entry);
413extern void delete_from_swap_cache(struct page *);
414extern void free_page_and_swap_cache(struct page *);
415extern void free_pages_and_swap_cache(struct page **, int);
416extern struct page *lookup_swap_cache(swp_entry_t entry,
417 struct vm_area_struct *vma,
418 unsigned long addr);
419extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
420 struct vm_area_struct *vma, unsigned long addr,
421 bool do_poll);
422extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t,
423 struct vm_area_struct *vma, unsigned long addr,
424 bool *new_page_allocated);
425extern struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
426 struct vm_fault *vmf);
427extern struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
428 struct vm_fault *vmf);
429
430/* linux/mm/swapfile.c */
431extern atomic_long_t nr_swap_pages;
432extern long total_swap_pages;
433extern atomic_t nr_rotate_swap;
434extern bool has_usable_swap(void);
435
436/* Swap 50% full? Release swapcache more aggressively.. */
437static inline bool vm_swap_full(void)
438{
439 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
440}
441
442static inline long get_nr_swap_pages(void)
443{
444 return atomic_long_read(&nr_swap_pages);
445}
446
447extern void si_swapinfo(struct sysinfo *);
448extern swp_entry_t get_swap_page(struct page *page);
449extern void put_swap_page(struct page *page, swp_entry_t entry);
450extern swp_entry_t get_swap_page_of_type(int);
451extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size);
452extern int add_swap_count_continuation(swp_entry_t, gfp_t);
453extern void swap_shmem_alloc(swp_entry_t);
454extern int swap_duplicate(swp_entry_t);
455extern int swapcache_prepare(swp_entry_t);
456extern void swap_free(swp_entry_t);
457extern void swapcache_free_entries(swp_entry_t *entries, int n);
458extern int free_swap_and_cache(swp_entry_t);
459extern int swap_type_of(dev_t, sector_t, struct block_device **);
460extern unsigned int count_swap_pages(int, int);
461extern sector_t map_swap_page(struct page *, struct block_device **);
462extern sector_t swapdev_block(int, pgoff_t);
463extern int page_swapcount(struct page *);
464extern int __swap_count(swp_entry_t entry);
465extern int __swp_swapcount(swp_entry_t entry);
466extern int swp_swapcount(swp_entry_t entry);
467extern struct swap_info_struct *page_swap_info(struct page *);
468extern struct swap_info_struct *swp_swap_info(swp_entry_t entry);
469extern bool reuse_swap_page(struct page *, int *);
470extern int try_to_free_swap(struct page *);
471struct backing_dev_info;
472extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
473extern void exit_swap_address_space(unsigned int type);
474extern struct swap_info_struct *get_swap_device(swp_entry_t entry);
475
476static inline void put_swap_device(struct swap_info_struct *si)
477{
478 rcu_read_unlock();
479}
480
481#else /* CONFIG_SWAP */
482
483static inline int swap_readpage(struct page *page, bool do_poll)
484{
485 return 0;
486}
487
488static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry)
489{
490 return NULL;
491}
492
493#define swap_address_space(entry) (NULL)
494#define get_nr_swap_pages() 0L
495#define total_swap_pages 0L
496#define total_swapcache_pages() 0UL
497#define vm_swap_full() 0
498
499#define si_swapinfo(val) \
500 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
501/* only sparc can not include linux/pagemap.h in this file
502 * so leave put_page and release_pages undeclared... */
503#define free_page_and_swap_cache(page) \
504 put_page(page)
505#define free_pages_and_swap_cache(pages, nr) \
506 release_pages((pages), (nr));
507
508static inline void show_swap_cache_info(void)
509{
510}
511
512#define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
513#define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
514
515static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
516{
517 return 0;
518}
519
520static inline void swap_shmem_alloc(swp_entry_t swp)
521{
522}
523
524static inline int swap_duplicate(swp_entry_t swp)
525{
526 return 0;
527}
528
529static inline void swap_free(swp_entry_t swp)
530{
531}
532
533static inline void put_swap_page(struct page *page, swp_entry_t swp)
534{
535}
536
537static inline struct page *swap_cluster_readahead(swp_entry_t entry,
538 gfp_t gfp_mask, struct vm_fault *vmf)
539{
540 return NULL;
541}
542
543static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
544 struct vm_fault *vmf)
545{
546 return NULL;
547}
548
549static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
550{
551 return 0;
552}
553
554static inline struct page *lookup_swap_cache(swp_entry_t swp,
555 struct vm_area_struct *vma,
556 unsigned long addr)
557{
558 return NULL;
559}
560
561static inline int add_to_swap(struct page *page)
562{
563 return 0;
564}
565
566static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
567 gfp_t gfp_mask)
568{
569 return -1;
570}
571
572static inline void __delete_from_swap_cache(struct page *page,
573 swp_entry_t entry)
574{
575}
576
577static inline void delete_from_swap_cache(struct page *page)
578{
579}
580
581static inline int page_swapcount(struct page *page)
582{
583 return 0;
584}
585
586static inline int __swap_count(swp_entry_t entry)
587{
588 return 0;
589}
590
591static inline int __swp_swapcount(swp_entry_t entry)
592{
593 return 0;
594}
595
596static inline int swp_swapcount(swp_entry_t entry)
597{
598 return 0;
599}
600
601#define reuse_swap_page(page, total_map_swapcount) \
602 (page_trans_huge_mapcount(page, total_map_swapcount) == 1)
603
604static inline int try_to_free_swap(struct page *page)
605{
606 return 0;
607}
608
609static inline swp_entry_t get_swap_page(struct page *page)
610{
611 swp_entry_t entry;
612 entry.val = 0;
613 return entry;
614}
615
616#endif /* CONFIG_SWAP */
617
618#ifdef CONFIG_THP_SWAP
619extern int split_swap_cluster(swp_entry_t entry);
620#else
621static inline int split_swap_cluster(swp_entry_t entry)
622{
623 return 0;
624}
625#endif
626
627#ifdef CONFIG_MEMCG
628static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
629{
630 /* Cgroup2 doesn't have per-cgroup swappiness */
631 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
632 return vm_swappiness;
633
634 /* root ? */
635 if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg))
636 return vm_swappiness;
637
638 return memcg->swappiness;
639}
640#else
641static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
642{
643 return vm_swappiness;
644}
645#endif
646
647#if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
648extern void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg, int node,
649 gfp_t gfp_mask);
650#else
651static inline void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg,
652 int node, gfp_t gfp_mask)
653{
654}
655#endif
656
657#ifdef CONFIG_MEMCG_SWAP
658extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);
659extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);
660extern void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
661extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
662extern bool mem_cgroup_swap_full(struct page *page);
663#else
664static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
665{
666}
667
668static inline int mem_cgroup_try_charge_swap(struct page *page,
669 swp_entry_t entry)
670{
671 return 0;
672}
673
674static inline void mem_cgroup_uncharge_swap(swp_entry_t entry,
675 unsigned int nr_pages)
676{
677}
678
679static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
680{
681 return get_nr_swap_pages();
682}
683
684static inline bool mem_cgroup_swap_full(struct page *page)
685{
686 return vm_swap_full();
687}
688#endif
689
690#endif /* __KERNEL__*/
691#endif /* _LINUX_SWAP_H */