Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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/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
19struct notifier_block;
20
21struct bio;
22
23struct pagevec;
24
25#define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
26#define SWAP_FLAG_PRIO_MASK 0x7fff
27#define SWAP_FLAG_DISCARD 0x10000 /* enable discard for swap */
28#define SWAP_FLAG_DISCARD_ONCE 0x20000 /* discard swap area at swapon-time */
29#define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */
30
31#define SWAP_FLAGS_VALID (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \
32 SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \
33 SWAP_FLAG_DISCARD_PAGES)
34#define SWAP_BATCH 64
35
36static inline int current_is_kswapd(void)
37{
38 return current->flags & PF_KSWAPD;
39}
40
41/*
42 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
43 * be swapped to. The swap type and the offset into that swap type are
44 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits
45 * for the type means that the maximum number of swapcache pages is 27 bits
46 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
47 * the type/offset into the pte as 5/27 as well.
48 */
49#define MAX_SWAPFILES_SHIFT 5
50
51/*
52 * Use some of the swap files numbers for other purposes. This
53 * is a convenient way to hook into the VM to trigger special
54 * actions on faults.
55 */
56
57/*
58 * PTE markers are used to persist information onto PTEs that otherwise
59 * should be a none pte. As its name "PTE" hints, it should only be
60 * applied to the leaves of pgtables.
61 */
62#define SWP_PTE_MARKER_NUM 1
63#define SWP_PTE_MARKER (MAX_SWAPFILES + SWP_HWPOISON_NUM + \
64 SWP_MIGRATION_NUM + SWP_DEVICE_NUM)
65
66/*
67 * Unaddressable device memory support. See include/linux/hmm.h and
68 * Documentation/mm/hmm.rst. Short description is we need struct pages for
69 * device memory that is unaddressable (inaccessible) by CPU, so that we can
70 * migrate part of a process memory to device memory.
71 *
72 * When a page is migrated from CPU to device, we set the CPU page table entry
73 * to a special SWP_DEVICE_{READ|WRITE} entry.
74 *
75 * When a page is mapped by the device for exclusive access we set the CPU page
76 * table entries to a special SWP_DEVICE_EXCLUSIVE entry.
77 */
78#ifdef CONFIG_DEVICE_PRIVATE
79#define SWP_DEVICE_NUM 3
80#define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM)
81#define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1)
82#define SWP_DEVICE_EXCLUSIVE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2)
83#else
84#define SWP_DEVICE_NUM 0
85#endif
86
87/*
88 * Page migration support.
89 *
90 * SWP_MIGRATION_READ_EXCLUSIVE is only applicable to anonymous pages and
91 * indicates that the referenced (part of) an anonymous page is exclusive to
92 * a single process. For SWP_MIGRATION_WRITE, that information is implicit:
93 * (part of) an anonymous page that are mapped writable are exclusive to a
94 * single process.
95 */
96#ifdef CONFIG_MIGRATION
97#define SWP_MIGRATION_NUM 3
98#define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
99#define SWP_MIGRATION_READ_EXCLUSIVE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
100#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 2)
101#else
102#define SWP_MIGRATION_NUM 0
103#endif
104
105/*
106 * Handling of hardware poisoned pages with memory corruption.
107 */
108#ifdef CONFIG_MEMORY_FAILURE
109#define SWP_HWPOISON_NUM 1
110#define SWP_HWPOISON MAX_SWAPFILES
111#else
112#define SWP_HWPOISON_NUM 0
113#endif
114
115#define MAX_SWAPFILES \
116 ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \
117 SWP_MIGRATION_NUM - SWP_HWPOISON_NUM - \
118 SWP_PTE_MARKER_NUM)
119
120/*
121 * Magic header for a swap area. The first part of the union is
122 * what the swap magic looks like for the old (limited to 128MB)
123 * swap area format, the second part of the union adds - in the
124 * old reserved area - some extra information. Note that the first
125 * kilobyte is reserved for boot loader or disk label stuff...
126 *
127 * Having the magic at the end of the PAGE_SIZE makes detecting swap
128 * areas somewhat tricky on machines that support multiple page sizes.
129 * For 2.5 we'll probably want to move the magic to just beyond the
130 * bootbits...
131 */
132union swap_header {
133 struct {
134 char reserved[PAGE_SIZE - 10];
135 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
136 } magic;
137 struct {
138 char bootbits[1024]; /* Space for disklabel etc. */
139 __u32 version;
140 __u32 last_page;
141 __u32 nr_badpages;
142 unsigned char sws_uuid[16];
143 unsigned char sws_volume[16];
144 __u32 padding[117];
145 __u32 badpages[1];
146 } info;
147};
148
149/*
150 * current->reclaim_state points to one of these when a task is running
151 * memory reclaim
152 */
153struct reclaim_state {
154 /* pages reclaimed outside of LRU-based reclaim */
155 unsigned long reclaimed;
156#ifdef CONFIG_LRU_GEN
157 /* per-thread mm walk data */
158 struct lru_gen_mm_walk *mm_walk;
159#endif
160};
161
162/*
163 * mm_account_reclaimed_pages(): account reclaimed pages outside of LRU-based
164 * reclaim
165 * @pages: number of pages reclaimed
166 *
167 * If the current process is undergoing a reclaim operation, increment the
168 * number of reclaimed pages by @pages.
169 */
170static inline void mm_account_reclaimed_pages(unsigned long pages)
171{
172 if (current->reclaim_state)
173 current->reclaim_state->reclaimed += pages;
174}
175
176#ifdef __KERNEL__
177
178struct address_space;
179struct sysinfo;
180struct writeback_control;
181struct zone;
182
183/*
184 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
185 * disk blocks. A rbtree of swap extents maps the entire swapfile (Where the
186 * term `swapfile' refers to either a blockdevice or an IS_REG file). Apart
187 * from setup, they're handled identically.
188 *
189 * We always assume that blocks are of size PAGE_SIZE.
190 */
191struct swap_extent {
192 struct rb_node rb_node;
193 pgoff_t start_page;
194 pgoff_t nr_pages;
195 sector_t start_block;
196};
197
198/*
199 * Max bad pages in the new format..
200 */
201#define MAX_SWAP_BADPAGES \
202 ((offsetof(union swap_header, magic.magic) - \
203 offsetof(union swap_header, info.badpages)) / sizeof(int))
204
205enum {
206 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
207 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
208 SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */
209 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
210 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
211 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
212 SWP_BLKDEV = (1 << 6), /* its a block device */
213 SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */
214 SWP_FS_OPS = (1 << 8), /* swapfile operations go through fs */
215 SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */
216 SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */
217 SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */
218 SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */
219 /* add others here before... */
220};
221
222#define SWAP_CLUSTER_MAX 32UL
223#define SWAP_CLUSTER_MAX_SKIPPED (SWAP_CLUSTER_MAX << 10)
224#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
225
226/* Bit flag in swap_map */
227#define COUNT_CONTINUED 0x80 /* Flag swap_map continuation for full count */
228
229/* Special value in first swap_map */
230#define SWAP_MAP_MAX 0x3e /* Max count */
231#define SWAP_MAP_BAD 0x3f /* Note page is bad */
232
233/* Special value in each swap_map continuation */
234#define SWAP_CONT_MAX 0x7f /* Max count */
235
236/*
237 * The first page in the swap file is the swap header, which is always marked
238 * bad to prevent it from being allocated as an entry. This also prevents the
239 * cluster to which it belongs being marked free. Therefore 0 is safe to use as
240 * a sentinel to indicate an entry is not valid.
241 */
242#define SWAP_ENTRY_INVALID 0
243
244#ifdef CONFIG_THP_SWAP
245#define SWAP_NR_ORDERS (PMD_ORDER + 1)
246#else
247#define SWAP_NR_ORDERS 1
248#endif
249
250/*
251 * We keep using same cluster for rotational device so IO will be sequential.
252 * The purpose is to optimize SWAP throughput on these device.
253 */
254struct swap_sequential_cluster {
255 unsigned int next[SWAP_NR_ORDERS]; /* Likely next allocation offset */
256};
257
258/*
259 * The in-memory structure used to track swap areas.
260 */
261struct swap_info_struct {
262 struct percpu_ref users; /* indicate and keep swap device valid. */
263 unsigned long flags; /* SWP_USED etc: see above */
264 signed short prio; /* swap priority of this type */
265 struct plist_node list; /* entry in swap_active_head */
266 signed char type; /* strange name for an index */
267 unsigned int max; /* extent of the swap_map */
268 unsigned char *swap_map; /* vmalloc'ed array of usage counts */
269 unsigned long *zeromap; /* kvmalloc'ed bitmap to track zero pages */
270 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
271 struct list_head free_clusters; /* free clusters list */
272 struct list_head full_clusters; /* full clusters list */
273 struct list_head nonfull_clusters[SWAP_NR_ORDERS];
274 /* list of cluster that contains at least one free slot */
275 struct list_head frag_clusters[SWAP_NR_ORDERS];
276 /* list of cluster that are fragmented or contented */
277 unsigned int pages; /* total of usable pages of swap */
278 atomic_long_t inuse_pages; /* number of those currently in use */
279 struct swap_sequential_cluster *global_cluster; /* Use one global cluster for rotating device */
280 spinlock_t global_cluster_lock; /* Serialize usage of global cluster */
281 struct rb_root swap_extent_root;/* root of the swap extent rbtree */
282 struct block_device *bdev; /* swap device or bdev of swap file */
283 struct file *swap_file; /* seldom referenced */
284 struct completion comp; /* seldom referenced */
285 spinlock_t lock; /*
286 * protect map scan related fields like
287 * swap_map, inuse_pages and all cluster
288 * lists. other fields are only changed
289 * at swapon/swapoff, so are protected
290 * by swap_lock. changing flags need
291 * hold this lock and swap_lock. If
292 * both locks need hold, hold swap_lock
293 * first.
294 */
295 spinlock_t cont_lock; /*
296 * protect swap count continuation page
297 * list.
298 */
299 struct work_struct discard_work; /* discard worker */
300 struct work_struct reclaim_work; /* reclaim worker */
301 struct list_head discard_clusters; /* discard clusters list */
302 struct plist_node avail_list; /* entry in swap_avail_head */
303};
304
305static inline swp_entry_t page_swap_entry(struct page *page)
306{
307 struct folio *folio = page_folio(page);
308 swp_entry_t entry = folio->swap;
309
310 entry.val += folio_page_idx(folio, page);
311 return entry;
312}
313
314/* linux/mm/workingset.c */
315bool workingset_test_recent(void *shadow, bool file, bool *workingset,
316 bool flush);
317void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages);
318void *workingset_eviction(struct folio *folio, struct mem_cgroup *target_memcg);
319void workingset_refault(struct folio *folio, void *shadow);
320void workingset_activation(struct folio *folio);
321
322/* linux/mm/page_alloc.c */
323extern unsigned long totalreserve_pages;
324
325/* Definition of global_zone_page_state not available yet */
326#define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
327
328
329/* linux/mm/swap.c */
330void lru_note_cost_unlock_irq(struct lruvec *lruvec, bool file,
331 unsigned int nr_io, unsigned int nr_rotated)
332 __releases(lruvec->lru_lock);
333void lru_note_cost_refault(struct folio *);
334void folio_add_lru(struct folio *);
335void folio_add_lru_vma(struct folio *, struct vm_area_struct *);
336void mark_page_accessed(struct page *);
337void folio_mark_accessed(struct folio *);
338
339static inline bool folio_may_be_lru_cached(struct folio *folio)
340{
341 /*
342 * Holding PMD-sized folios in per-CPU LRU cache unbalances accounting.
343 * Holding small numbers of low-order mTHP folios in per-CPU LRU cache
344 * will be sensible, but nobody has implemented and tested that yet.
345 */
346 return !folio_test_large(folio);
347}
348
349extern atomic_t lru_disable_count;
350
351static inline bool lru_cache_disabled(void)
352{
353 return atomic_read(&lru_disable_count);
354}
355
356static inline void lru_cache_enable(void)
357{
358 atomic_dec(&lru_disable_count);
359}
360
361extern void lru_cache_disable(void);
362extern void lru_add_drain(void);
363extern void lru_add_drain_cpu(int cpu);
364extern void lru_add_drain_cpu_zone(struct zone *zone);
365extern void lru_add_drain_all(void);
366void folio_deactivate(struct folio *folio);
367void folio_mark_lazyfree(struct folio *folio);
368extern void swap_setup(void);
369
370/* linux/mm/vmscan.c */
371extern unsigned long zone_reclaimable_pages(struct zone *zone);
372extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
373 gfp_t gfp_mask, nodemask_t *mask);
374
375#define MEMCG_RECLAIM_MAY_SWAP (1 << 1)
376#define MEMCG_RECLAIM_PROACTIVE (1 << 2)
377#define MIN_SWAPPINESS 0
378#define MAX_SWAPPINESS 200
379
380/* Just reclaim from anon folios in proactive memory reclaim */
381#define SWAPPINESS_ANON_ONLY (MAX_SWAPPINESS + 1)
382
383extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
384 unsigned long nr_pages,
385 gfp_t gfp_mask,
386 unsigned int reclaim_options,
387 int *swappiness);
388extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
389 gfp_t gfp_mask, bool noswap,
390 pg_data_t *pgdat,
391 unsigned long *nr_scanned);
392extern unsigned long shrink_all_memory(unsigned long nr_pages);
393extern int vm_swappiness;
394long remove_mapping(struct address_space *mapping, struct folio *folio);
395
396#if defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
397extern int reclaim_register_node(struct node *node);
398extern void reclaim_unregister_node(struct node *node);
399
400#else
401
402static inline int reclaim_register_node(struct node *node)
403{
404 return 0;
405}
406
407static inline void reclaim_unregister_node(struct node *node)
408{
409}
410#endif /* CONFIG_SYSFS && CONFIG_NUMA */
411
412#ifdef CONFIG_NUMA
413extern int sysctl_min_unmapped_ratio;
414extern int sysctl_min_slab_ratio;
415#endif
416
417void check_move_unevictable_folios(struct folio_batch *fbatch);
418
419extern void __meminit kswapd_run(int nid);
420extern void __meminit kswapd_stop(int nid);
421
422#ifdef CONFIG_SWAP
423
424int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
425 unsigned long nr_pages, sector_t start_block);
426int generic_swapfile_activate(struct swap_info_struct *, struct file *,
427 sector_t *);
428
429static inline unsigned long total_swapcache_pages(void)
430{
431 return global_node_page_state(NR_SWAPCACHE);
432}
433
434void free_swap_cache(struct folio *folio);
435void free_folio_and_swap_cache(struct folio *folio);
436void free_pages_and_swap_cache(struct encoded_page **, int);
437/* linux/mm/swapfile.c */
438extern atomic_long_t nr_swap_pages;
439extern long total_swap_pages;
440extern atomic_t nr_rotate_swap;
441
442/* Swap 50% full? Release swapcache more aggressively.. */
443static inline bool vm_swap_full(void)
444{
445 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
446}
447
448static inline long get_nr_swap_pages(void)
449{
450 return atomic_long_read(&nr_swap_pages);
451}
452
453extern void si_swapinfo(struct sysinfo *);
454extern int add_swap_count_continuation(swp_entry_t, gfp_t);
455int swap_type_of(dev_t device, sector_t offset);
456int find_first_swap(dev_t *device);
457extern unsigned int count_swap_pages(int, int);
458extern sector_t swapdev_block(int, pgoff_t);
459extern int __swap_count(swp_entry_t entry);
460extern bool swap_entry_swapped(struct swap_info_struct *si, swp_entry_t entry);
461extern int swp_swapcount(swp_entry_t entry);
462struct backing_dev_info;
463extern struct swap_info_struct *get_swap_device(swp_entry_t entry);
464sector_t swap_folio_sector(struct folio *folio);
465
466/*
467 * If there is an existing swap slot reference (swap entry) and the caller
468 * guarantees that there is no race modification of it (e.g., PTL
469 * protecting the swap entry in page table; shmem's cmpxchg protects t
470 * he swap entry in shmem mapping), these two helpers below can be used
471 * to put/dup the entries directly.
472 *
473 * All entries must be allocated by folio_alloc_swap(). And they must have
474 * a swap count > 1. See comments of folio_*_swap helpers for more info.
475 */
476int swap_dup_entry_direct(swp_entry_t entry);
477void swap_put_entries_direct(swp_entry_t entry, int nr);
478
479/*
480 * folio_free_swap tries to free the swap entries pinned by a swap cache
481 * folio, it has to be here to be called by other components.
482 */
483bool folio_free_swap(struct folio *folio);
484
485/* Allocate / free (hibernation) exclusive entries */
486swp_entry_t swap_alloc_hibernation_slot(int type);
487void swap_free_hibernation_slot(swp_entry_t entry);
488
489static inline void put_swap_device(struct swap_info_struct *si)
490{
491 percpu_ref_put(&si->users);
492}
493
494#else /* CONFIG_SWAP */
495static inline struct swap_info_struct *get_swap_device(swp_entry_t entry)
496{
497 return NULL;
498}
499
500static inline void put_swap_device(struct swap_info_struct *si)
501{
502}
503
504#define get_nr_swap_pages() 0L
505#define total_swap_pages 0L
506#define total_swapcache_pages() 0UL
507#define vm_swap_full() 0
508
509#define si_swapinfo(val) \
510 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
511#define free_folio_and_swap_cache(folio) \
512 folio_put(folio)
513#define free_pages_and_swap_cache(pages, nr) \
514 release_pages((pages), (nr));
515
516static inline void free_swap_cache(struct folio *folio)
517{
518}
519
520static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
521{
522 return 0;
523}
524
525static inline int swap_dup_entry_direct(swp_entry_t ent)
526{
527 return 0;
528}
529
530static inline void swap_put_entries_direct(swp_entry_t ent, int nr)
531{
532}
533
534static inline int __swap_count(swp_entry_t entry)
535{
536 return 0;
537}
538
539static inline bool swap_entry_swapped(struct swap_info_struct *si, swp_entry_t entry)
540{
541 return false;
542}
543
544static inline int swp_swapcount(swp_entry_t entry)
545{
546 return 0;
547}
548
549static inline bool folio_free_swap(struct folio *folio)
550{
551 return false;
552}
553
554static inline int add_swap_extent(struct swap_info_struct *sis,
555 unsigned long start_page,
556 unsigned long nr_pages, sector_t start_block)
557{
558 return -EINVAL;
559}
560#endif /* CONFIG_SWAP */
561#ifdef CONFIG_MEMCG
562static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
563{
564 /* Cgroup2 doesn't have per-cgroup swappiness */
565 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
566 return READ_ONCE(vm_swappiness);
567
568 /* root ? */
569 if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg))
570 return READ_ONCE(vm_swappiness);
571
572 return READ_ONCE(memcg->swappiness);
573}
574#else
575static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
576{
577 return READ_ONCE(vm_swappiness);
578}
579#endif
580
581#if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
582void __folio_throttle_swaprate(struct folio *folio, gfp_t gfp);
583static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp)
584{
585 if (mem_cgroup_disabled())
586 return;
587 __folio_throttle_swaprate(folio, gfp);
588}
589#else
590static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp)
591{
592}
593#endif
594
595#if defined(CONFIG_MEMCG) && defined(CONFIG_SWAP)
596int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry);
597static inline int mem_cgroup_try_charge_swap(struct folio *folio,
598 swp_entry_t entry)
599{
600 if (mem_cgroup_disabled())
601 return 0;
602 return __mem_cgroup_try_charge_swap(folio, entry);
603}
604
605extern void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
606static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
607{
608 if (mem_cgroup_disabled())
609 return;
610 __mem_cgroup_uncharge_swap(entry, nr_pages);
611}
612
613extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
614extern bool mem_cgroup_swap_full(struct folio *folio);
615#else
616static inline int mem_cgroup_try_charge_swap(struct folio *folio,
617 swp_entry_t entry)
618{
619 return 0;
620}
621
622static inline void mem_cgroup_uncharge_swap(swp_entry_t entry,
623 unsigned int nr_pages)
624{
625}
626
627static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
628{
629 return get_nr_swap_pages();
630}
631
632static inline bool mem_cgroup_swap_full(struct folio *folio)
633{
634 return vm_swap_full();
635}
636#endif
637
638#endif /* __KERNEL__*/
639#endif /* _LINUX_SWAP_H */