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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _LINUX_SWAP_H
2#define _LINUX_SWAP_H
3
Linus Torvalds1da177e2005-04-16 15:20:36 -07004#include <linux/spinlock.h>
5#include <linux/linkage.h>
6#include <linux/mmzone.h>
7#include <linux/list.h>
Balbir Singh66e17072008-02-07 00:13:56 -08008#include <linux/memcontrol.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07009#include <linux/sched.h>
Lee Schermerhornaf936a12008-10-18 20:26:53 -070010#include <linux/node.h>
Shaohua Li33806f02013-02-22 16:34:37 -080011#include <linux/fs.h>
Arun Sharma600634972011-07-26 16:09:06 -070012#include <linux/atomic.h>
Mel Gormanc53954a2013-07-03 15:02:34 -070013#include <linux/page-flags.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <asm/page.h>
15
Martin Schwidefsky8bc719d2006-09-25 23:31:20 -070016struct notifier_block;
17
Andrew Mortonab954162006-09-25 23:32:42 -070018struct bio;
19
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
21#define SWAP_FLAG_PRIO_MASK 0x7fff
22#define SWAP_FLAG_PRIO_SHIFT 0
Rafael Aquinidcf6b7d2013-07-03 15:02:46 -070023#define SWAP_FLAG_DISCARD 0x10000 /* enable discard for swap */
24#define SWAP_FLAG_DISCARD_ONCE 0x20000 /* discard swap area at swapon-time */
25#define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */
Linus Torvalds1da177e2005-04-16 15:20:36 -070026
Hugh Dickinsd15cab92012-03-28 14:42:42 -070027#define SWAP_FLAGS_VALID (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \
Rafael Aquinidcf6b7d2013-07-03 15:02:46 -070028 SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \
29 SWAP_FLAG_DISCARD_PAGES)
Hugh Dickinsd15cab92012-03-28 14:42:42 -070030
Linus Torvalds1da177e2005-04-16 15:20:36 -070031static inline int current_is_kswapd(void)
32{
33 return current->flags & PF_KSWAPD;
34}
35
36/*
37 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
38 * be swapped to. The swap type and the offset into that swap type are
39 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits
40 * for the type means that the maximum number of swapcache pages is 27 bits
41 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
42 * the type/offset into the pte as 5/27 as well.
43 */
44#define MAX_SWAPFILES_SHIFT 5
Andi Kleena7420aa2009-09-16 11:50:05 +020045
46/*
47 * Use some of the swap files numbers for other purposes. This
48 * is a convenient way to hook into the VM to trigger special
49 * actions on faults.
50 */
51
52/*
53 * NUMA node memory migration support
54 */
55#ifdef CONFIG_MIGRATION
56#define SWP_MIGRATION_NUM 2
57#define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
58#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
Christoph Lameter06972122006-06-23 02:03:35 -070059#else
Andi Kleena7420aa2009-09-16 11:50:05 +020060#define SWP_MIGRATION_NUM 0
Christoph Lameter06972122006-06-23 02:03:35 -070061#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63/*
Andi Kleena7420aa2009-09-16 11:50:05 +020064 * Handling of hardware poisoned pages with memory corruption.
65 */
66#ifdef CONFIG_MEMORY_FAILURE
67#define SWP_HWPOISON_NUM 1
68#define SWP_HWPOISON MAX_SWAPFILES
69#else
70#define SWP_HWPOISON_NUM 0
71#endif
72
73#define MAX_SWAPFILES \
74 ((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)
75
76/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 * Magic header for a swap area. The first part of the union is
78 * what the swap magic looks like for the old (limited to 128MB)
79 * swap area format, the second part of the union adds - in the
80 * old reserved area - some extra information. Note that the first
81 * kilobyte is reserved for boot loader or disk label stuff...
82 *
83 * Having the magic at the end of the PAGE_SIZE makes detecting swap
84 * areas somewhat tricky on machines that support multiple page sizes.
85 * For 2.5 we'll probably want to move the magic to just beyond the
86 * bootbits...
87 */
88union swap_header {
89 struct {
90 char reserved[PAGE_SIZE - 10];
91 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
92 } magic;
93 struct {
Andreas Dilgere8f03d02006-06-23 02:03:14 -070094 char bootbits[1024]; /* Space for disklabel etc. */
95 __u32 version;
96 __u32 last_page;
97 __u32 nr_badpages;
98 unsigned char sws_uuid[16];
99 unsigned char sws_volume[16];
100 __u32 padding[117];
101 __u32 badpages[1];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 } info;
103};
104
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105/*
106 * current->reclaim_state points to one of these when a task is running
107 * memory reclaim
108 */
109struct reclaim_state {
110 unsigned long reclaimed_slab;
111};
112
113#ifdef __KERNEL__
114
115struct address_space;
116struct sysinfo;
117struct writeback_control;
118struct zone;
119
120/*
121 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
122 * disk blocks. A list of swap extents maps the entire swapfile. (Where the
123 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
124 * from setup, they're handled identically.
125 *
126 * We always assume that blocks are of size PAGE_SIZE.
127 */
128struct swap_extent {
129 struct list_head list;
130 pgoff_t start_page;
131 pgoff_t nr_pages;
132 sector_t start_block;
133};
134
135/*
136 * Max bad pages in the new format..
137 */
138#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
139#define MAX_SWAP_BADPAGES \
140 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
141
142enum {
143 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
144 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
Rafael Aquinidcf6b7d2013-07-03 15:02:46 -0700145 SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */
Hugh Dickins7992fde2009-01-06 14:39:53 -0800146 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
Hugh Dickins20137a42009-01-06 14:39:54 -0800147 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
Hugh Dickins570a335b2009-12-14 17:58:46 -0800148 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
Nitin Guptab2725642010-05-17 11:02:42 +0530149 SWP_BLKDEV = (1 << 6), /* its a block device */
Mel Gorman62c230b2012-07-31 16:44:55 -0700150 SWP_FILE = (1 << 7), /* set after swap_activate success */
Rafael Aquinidcf6b7d2013-07-03 15:02:46 -0700151 SWP_AREA_DISCARD = (1 << 8), /* single-time swap area discards */
152 SWP_PAGE_DISCARD = (1 << 9), /* freed swap page-cluster discards */
Minchan Kimf0571422017-01-10 16:58:15 -0800153 SWP_STABLE_WRITES = (1 << 10), /* no overwrite PG_writeback pages */
Hugh Dickins52b7efdb2005-09-03 15:54:39 -0700154 /* add others here before... */
Minchan Kimf0571422017-01-10 16:58:15 -0800155 SWP_SCANNING = (1 << 11), /* refcount in scan_swap_map */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156};
157
Johannes Weinerd778df52013-02-22 16:32:12 -0800158#define SWAP_CLUSTER_MAX 32UL
Mel Gorman748446b2010-05-24 14:32:27 -0700159#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160
Hugh Dickins570a335b2009-12-14 17:58:46 -0800161#define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */
162#define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */
163#define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
164#define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */
165#define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */
Hugh Dickinsaaa46862009-12-14 17:58:47 -0800166#define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */
Hugh Dickins253d5532009-12-14 17:58:44 -0800167
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168/*
Shaohua Li2a8f9442013-09-11 14:20:28 -0700169 * We use this to track usage of a cluster. A cluster is a block of swap disk
170 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All
171 * free clusters are organized into a list. We fetch an entry from the list to
172 * get a free cluster.
173 *
174 * The data field stores next cluster if the cluster is free or cluster usage
175 * counter otherwise. The flags field determines if a cluster is free. This is
176 * protected by swap_info_struct.lock.
177 */
178struct swap_cluster_info {
179 unsigned int data:24;
180 unsigned int flags:8;
181};
182#define CLUSTER_FLAG_FREE 1 /* This cluster is free */
183#define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */
184
185/*
Shaohua Liebc2a1a2013-09-11 14:20:32 -0700186 * We assign a cluster to each CPU, so each CPU can allocate swap entry from
187 * its own cluster and swapout sequentially. The purpose is to optimize swapout
188 * throughput.
189 */
190struct percpu_cluster {
191 struct swap_cluster_info index; /* Current cluster index */
192 unsigned int next; /* Likely next allocation offset */
193};
194
Huang Ying6b534912016-10-07 16:58:42 -0700195struct swap_cluster_list {
196 struct swap_cluster_info head;
197 struct swap_cluster_info tail;
198};
199
Shaohua Liebc2a1a2013-09-11 14:20:32 -0700200/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 * The in-memory structure used to track swap areas.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 */
203struct swap_info_struct {
Hugh Dickinsefa90a92009-12-14 17:58:41 -0800204 unsigned long flags; /* SWP_USED etc: see above */
205 signed short prio; /* swap priority of this type */
Dan Streetman18ab4d42014-06-04 16:09:59 -0700206 struct plist_node list; /* entry in swap_active_head */
207 struct plist_node avail_list; /* entry in swap_avail_head */
Hugh Dickinsefa90a92009-12-14 17:58:41 -0800208 signed char type; /* strange name for an index */
Hugh Dickins75097652009-12-14 17:58:48 -0800209 unsigned int max; /* extent of the swap_map */
210 unsigned char *swap_map; /* vmalloc'ed array of usage counts */
Shaohua Li2a8f9442013-09-11 14:20:28 -0700211 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
Huang Ying6b534912016-10-07 16:58:42 -0700212 struct swap_cluster_list free_clusters; /* free clusters list */
Hugh Dickins75097652009-12-14 17:58:48 -0800213 unsigned int lowest_bit; /* index of first free in swap_map */
214 unsigned int highest_bit; /* index of last free in swap_map */
215 unsigned int pages; /* total of usable pages of swap */
216 unsigned int inuse_pages; /* number of those currently in use */
217 unsigned int cluster_next; /* likely index for next allocation */
218 unsigned int cluster_nr; /* countdown to next cluster search */
Shaohua Liebc2a1a2013-09-11 14:20:32 -0700219 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
Hugh Dickins75097652009-12-14 17:58:48 -0800220 struct swap_extent *curr_swap_extent;
221 struct swap_extent first_swap_extent;
222 struct block_device *bdev; /* swap device or bdev of swap file */
223 struct file *swap_file; /* seldom referenced */
224 unsigned int old_block_size; /* seldom referenced */
Dan Magenheimer38b5faf2012-04-09 17:08:06 -0600225#ifdef CONFIG_FRONTSWAP
226 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */
227 atomic_t frontswap_pages; /* frontswap pages in-use counter */
228#endif
Shaohua Liec8acf22013-02-22 16:34:38 -0800229 spinlock_t lock; /*
230 * protect map scan related fields like
231 * swap_map, lowest_bit, highest_bit,
232 * inuse_pages, cluster_next,
Shaohua Li815c2c52013-09-11 14:20:30 -0700233 * cluster_nr, lowest_alloc,
234 * highest_alloc, free/discard cluster
235 * list. other fields are only changed
236 * at swapon/swapoff, so are protected
237 * by swap_lock. changing flags need
238 * hold this lock and swap_lock. If
239 * both locks need hold, hold swap_lock
240 * first.
Shaohua Liec8acf22013-02-22 16:34:38 -0800241 */
Shaohua Li815c2c52013-09-11 14:20:30 -0700242 struct work_struct discard_work; /* discard worker */
Huang Ying6b534912016-10-07 16:58:42 -0700243 struct swap_cluster_list discard_clusters; /* discard clusters list */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244};
245
Johannes Weinera5289102014-04-03 14:47:51 -0700246/* linux/mm/workingset.c */
247void *workingset_eviction(struct address_space *mapping, struct page *page);
248bool workingset_refault(void *shadow);
249void workingset_activation(struct page *page);
Johannes Weiner14b46872016-12-12 16:43:52 -0800250void workingset_update_node(struct radix_tree_node *node, void *private);
Johannes Weinera5289102014-04-03 14:47:51 -0700251
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252/* linux/mm/page_alloc.c */
253extern unsigned long totalram_pages;
Hideo AOKIcb45b0e2006-04-10 22:52:59 -0700254extern unsigned long totalreserve_pages;
Zhang Yanfeiebec3862013-02-22 16:35:43 -0800255extern unsigned long nr_free_buffer_pages(void);
256extern unsigned long nr_free_pagecache_pages(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257
Christoph Lameter96177292007-02-10 01:43:03 -0800258/* Definition of global_page_state not available yet */
259#define nr_free_pages() global_page_state(NR_FREE_PAGES)
260
261
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262/* linux/mm/swap.c */
Mel Gormanc53954a2013-07-03 15:02:34 -0700263extern void lru_cache_add(struct page *);
Jianyu Zhan2329d372014-06-04 16:07:31 -0700264extern void lru_cache_add_anon(struct page *page);
265extern void lru_cache_add_file(struct page *page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700266extern void lru_add_page_tail(struct page *page, struct page *page_tail,
Shaohua Li5bc7b8a2013-04-29 15:08:36 -0700267 struct lruvec *lruvec, struct list_head *head);
Harvey Harrisonb3c97522008-02-13 15:03:15 -0800268extern void activate_page(struct page *);
269extern void mark_page_accessed(struct page *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270extern void lru_add_drain(void);
Konstantin Khlebnikovf0cb3c72012-03-21 16:34:06 -0700271extern void lru_add_drain_cpu(int cpu);
Chris Metcalf5fbc4612013-09-12 15:13:55 -0700272extern void lru_add_drain_all(void);
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700273extern void rotate_reclaimable_page(struct page *page);
Minchan Kimcc5993b2015-04-15 16:13:26 -0700274extern void deactivate_file_page(struct page *page);
Minchan Kim10853a02016-01-15 16:55:11 -0800275extern void deactivate_page(struct page *page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276extern void swap_setup(void);
277
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700278extern void add_page_to_unevictable_list(struct page *page);
279
Johannes Weiner00501b52014-08-08 14:19:20 -0700280extern void lru_cache_add_active_or_unevictable(struct page *page,
281 struct vm_area_struct *vma);
282
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283/* linux/mm/vmscan.c */
Mel Gorman5a1c84b2016-07-28 15:47:31 -0700284extern unsigned long zone_reclaimable_pages(struct zone *zone);
Mel Gorman599d0c92016-07-28 15:45:31 -0700285extern unsigned long pgdat_reclaimable_pages(struct pglist_data *pgdat);
Mel Gormandac1d272008-04-28 02:12:12 -0700286extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
KAMEZAWA Hiroyuki327c0e92009-03-31 15:23:31 -0700287 gfp_t gfp_mask, nodemask_t *mask);
Konstantin Khlebnikovf3fd4a62012-05-29 15:06:54 -0700288extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
Johannes Weinerb70a2a22014-10-09 15:28:56 -0700289extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
290 unsigned long nr_pages,
291 gfp_t gfp_mask,
292 bool may_swap);
Mel Gormana9dd0a82016-07-28 15:46:02 -0700293extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
Johannes Weiner185efc02011-09-14 16:21:58 -0700294 gfp_t gfp_mask, bool noswap,
Mel Gormanef8f2322016-07-28 15:46:05 -0700295 pg_data_t *pgdat,
Johannes Weiner185efc02011-09-14 16:21:58 -0700296 unsigned long *nr_scanned);
Andrew Morton69e05942006-03-22 00:08:19 -0800297extern unsigned long shrink_all_memory(unsigned long nr_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298extern int vm_swappiness;
Christoph Lameterb20a3502006-03-22 00:09:12 -0800299extern int remove_mapping(struct address_space *mapping, struct page *page);
Zhang Yanfeib21e0b92013-02-22 16:35:48 -0800300extern unsigned long vm_total_pages;
Christoph Lameterb20a3502006-03-22 00:09:12 -0800301
Christoph Lameter9eeff232006-01-18 17:42:31 -0800302#ifdef CONFIG_NUMA
Mel Gormana5f5f912016-07-28 15:46:32 -0700303extern int node_reclaim_mode;
Christoph Lameter96146342006-07-03 00:24:13 -0700304extern int sysctl_min_unmapped_ratio;
Christoph Lameter0ff38492006-09-25 23:31:52 -0700305extern int sysctl_min_slab_ratio;
Mel Gormana5f5f912016-07-28 15:46:32 -0700306extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int);
Christoph Lameter9eeff232006-01-18 17:42:31 -0800307#else
Mel Gormana5f5f912016-07-28 15:46:32 -0700308#define node_reclaim_mode 0
309static inline int node_reclaim(struct pglist_data *pgdat, gfp_t mask,
310 unsigned int order)
Christoph Lameter9eeff232006-01-18 17:42:31 -0800311{
312 return 0;
313}
314#endif
315
Hugh Dickins39b5f292012-10-08 16:33:18 -0700316extern int page_evictable(struct page *page);
Hugh Dickins24513262012-01-20 14:34:21 -0800317extern void check_move_unevictable_pages(struct page **, int nr_pages);
Lee Schermerhornaf936a12008-10-18 20:26:53 -0700318
Yasunori Goto3218ae12006-06-27 02:53:33 -0700319extern int kswapd_run(int nid);
David Rientjes8fe23e02009-12-14 17:58:33 -0800320extern void kswapd_stop(int nid);
Michal Hocko33398cf2015-09-08 15:01:02 -0700321
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322#ifdef CONFIG_SWAP
Christoph Hellwigbe297962016-11-01 07:40:16 -0600323
324#include <linux/blk_types.h> /* for bio_end_io_t */
325
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326/* linux/mm/page_io.c */
Minchan Kimaca8bf32009-06-16 15:33:02 -0700327extern int swap_readpage(struct page *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328extern int swap_writepage(struct page *page, struct writeback_control *wbc);
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200329extern void end_swap_bio_write(struct bio *bio);
Seth Jennings1eec6702013-04-29 15:08:35 -0700330extern int __swap_writepage(struct page *page, struct writeback_control *wbc,
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200331 bio_end_io_t end_write_func);
Mel Gorman62c230b2012-07-31 16:44:55 -0700332extern int swap_set_page_dirty(struct page *page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333
Mel Gormana509bc12012-07-31 16:44:57 -0700334int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
335 unsigned long nr_pages, sector_t start_block);
336int generic_swapfile_activate(struct swap_info_struct *, struct file *,
337 sector_t *);
338
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339/* linux/mm/swap_state.c */
Shaohua Li33806f02013-02-22 16:34:37 -0800340extern struct address_space swapper_spaces[];
341#define swap_address_space(entry) (&swapper_spaces[swp_type(entry)])
342extern unsigned long total_swapcache_pages(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343extern void show_swap_cache_info(void);
Shaohua Li5bc7b8a2013-04-29 15:08:36 -0700344extern int add_to_swap(struct page *, struct list_head *list);
Hugh Dickins73b12622008-02-04 22:28:50 -0800345extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
Seth Jennings2f772e62013-04-29 15:08:34 -0700346extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347extern void __delete_from_swap_cache(struct page *);
348extern void delete_from_swap_cache(struct page *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349extern void free_page_and_swap_cache(struct page *);
350extern void free_pages_and_swap_cache(struct page **, int);
Hugh Dickins46017e92008-02-04 22:28:41 -0800351extern struct page *lookup_swap_cache(swp_entry_t);
Hugh Dickins02098fe2008-02-04 22:28:42 -0800352extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
Hugh Dickins46017e92008-02-04 22:28:41 -0800353 struct vm_area_struct *vma, unsigned long addr);
Dmitry Safonov5b999aa2015-09-08 15:05:00 -0700354extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t,
355 struct vm_area_struct *vma, unsigned long addr,
356 bool *new_page_allocated);
Hugh Dickins02098fe2008-02-04 22:28:42 -0800357extern struct page *swapin_readahead(swp_entry_t, gfp_t,
Hugh Dickins46017e92008-02-04 22:28:41 -0800358 struct vm_area_struct *vma, unsigned long addr);
359
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360/* linux/mm/swapfile.c */
Shaohua Liec8acf22013-02-22 16:34:38 -0800361extern atomic_long_t nr_swap_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362extern long total_swap_pages;
Shaohua Liec8acf22013-02-22 16:34:38 -0800363
364/* Swap 50% full? Release swapcache more aggressively.. */
365static inline bool vm_swap_full(void)
366{
367 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
368}
369
370static inline long get_nr_swap_pages(void)
371{
372 return atomic_long_read(&nr_swap_pages);
373}
374
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375extern void si_swapinfo(struct sysinfo *);
376extern swp_entry_t get_swap_page(void);
Hugh Dickins910321e2010-09-09 16:38:07 -0700377extern swp_entry_t get_swap_page_of_type(int);
Hugh Dickins570a335b2009-12-14 17:58:46 -0800378extern int add_swap_count_continuation(swp_entry_t, gfp_t);
Hugh Dickinsaaa46862009-12-14 17:58:47 -0800379extern void swap_shmem_alloc(swp_entry_t);
Hugh Dickins570a335b2009-12-14 17:58:46 -0800380extern int swap_duplicate(swp_entry_t);
381extern int swapcache_prepare(swp_entry_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382extern void swap_free(swp_entry_t);
Johannes Weiner0a31bc92014-08-08 14:19:22 -0700383extern void swapcache_free(swp_entry_t);
Hugh Dickins2509ef22009-01-06 14:40:10 -0800384extern int free_swap_and_cache(swp_entry_t);
Rafael J. Wysocki7bf23682007-01-05 16:36:28 -0800385extern int swap_type_of(dev_t, sector_t, struct block_device **);
Rafael J. Wysockif577eb32006-03-23 02:59:59 -0800386extern unsigned int count_swap_pages(int, int);
Lee Schermerhornd4906e12009-12-14 17:58:49 -0800387extern sector_t map_swap_page(struct page *, struct block_device **);
Rafael J. Wysocki3aef83e2006-12-06 20:34:10 -0800388extern sector_t swapdev_block(int, pgoff_t);
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700389extern int page_swapcount(struct page *);
Minchan Kim8334b962015-09-08 15:00:24 -0700390extern int swp_swapcount(swp_entry_t entry);
Mel Gormanf981c592012-07-31 16:44:47 -0700391extern struct swap_info_struct *page_swap_info(struct page *);
Andrea Arcangeli6d0a07e2016-05-12 15:42:25 -0700392extern bool reuse_swap_page(struct page *, int *);
Hugh Dickinsa2c43ee2009-01-06 14:39:36 -0800393extern int try_to_free_swap(struct page *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394struct backing_dev_info;
395
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396#else /* CONFIG_SWAP */
397
Joonsoo Kimd2cf5ad2013-09-11 14:21:29 -0700398#define swap_address_space(entry) (NULL)
Shaohua Liec8acf22013-02-22 16:34:38 -0800399#define get_nr_swap_pages() 0L
Hugh Dickinsb9627162009-01-06 14:39:41 -0800400#define total_swap_pages 0L
Shaohua Li33806f02013-02-22 16:34:37 -0800401#define total_swapcache_pages() 0UL
Shaohua Liec8acf22013-02-22 16:34:38 -0800402#define vm_swap_full() 0
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403
404#define si_swapinfo(val) \
405 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
Olaf Hering9ae5b3c2005-08-07 09:42:24 -0700406/* only sparc can not include linux/pagemap.h in this file
Kirill A. Shutemovea1754a2016-04-01 15:29:48 +0300407 * so leave put_page and release_pages undeclared... */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408#define free_page_and_swap_cache(page) \
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300409 put_page(page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410#define free_pages_and_swap_cache(pages, nr) \
Mel Gormanb745bc82014-06-04 16:10:22 -0700411 release_pages((pages), (nr), false);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412
Con Kolivasbd96b9e2006-06-23 02:03:42 -0700413static inline void show_swap_cache_info(void)
414{
415}
416
Hugh Dickins2509ef22009-01-06 14:40:10 -0800417#define free_swap_and_cache(swp) is_migration_entry(swp)
KAMEZAWA Hiroyukicb4b86b2009-06-16 15:32:52 -0700418#define swapcache_prepare(swp) is_migration_entry(swp)
Con Kolivasbd96b9e2006-06-23 02:03:42 -0700419
Hugh Dickins570a335b2009-12-14 17:58:46 -0800420static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
KAMEZAWA Hiroyuki355cfa72009-06-16 15:32:53 -0700421{
Hugh Dickins570a335b2009-12-14 17:58:46 -0800422 return 0;
423}
424
Hugh Dickinsaaa46862009-12-14 17:58:47 -0800425static inline void swap_shmem_alloc(swp_entry_t swp)
426{
427}
428
Hugh Dickins570a335b2009-12-14 17:58:46 -0800429static inline int swap_duplicate(swp_entry_t swp)
430{
431 return 0;
KAMEZAWA Hiroyuki355cfa72009-06-16 15:32:53 -0700432}
433
Con Kolivasbd96b9e2006-06-23 02:03:42 -0700434static inline void swap_free(swp_entry_t swp)
435{
436}
437
Johannes Weiner0a31bc92014-08-08 14:19:22 -0700438static inline void swapcache_free(swp_entry_t swp)
KAMEZAWA Hiroyukicb4b86b2009-06-16 15:32:52 -0700439{
440}
441
Hugh Dickins02098fe2008-02-04 22:28:42 -0800442static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
Con Kolivasbd96b9e2006-06-23 02:03:42 -0700443 struct vm_area_struct *vma, unsigned long addr)
444{
445 return NULL;
446}
447
Hugh Dickins9fab5612009-03-31 15:23:33 -0700448static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
449{
450 return 0;
451}
452
Con Kolivasbd96b9e2006-06-23 02:03:42 -0700453static inline struct page *lookup_swap_cache(swp_entry_t swp)
454{
455 return NULL;
456}
457
Shaohua Li5bc7b8a2013-04-29 15:08:36 -0700458static inline int add_to_swap(struct page *page, struct list_head *list)
Hugh Dickins60371d92009-01-06 14:39:40 -0800459{
460 return 0;
461}
462
Hugh Dickins73b12622008-02-04 22:28:50 -0800463static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
464 gfp_t gfp_mask)
Con Kolivasbd96b9e2006-06-23 02:03:42 -0700465{
Hugh Dickins73b12622008-02-04 22:28:50 -0800466 return -1;
Con Kolivasbd96b9e2006-06-23 02:03:42 -0700467}
468
469static inline void __delete_from_swap_cache(struct page *page)
470{
471}
472
473static inline void delete_from_swap_cache(struct page *page)
474{
475}
476
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700477static inline int page_swapcount(struct page *page)
478{
479 return 0;
480}
481
Minchan Kim8334b962015-09-08 15:00:24 -0700482static inline int swp_swapcount(swp_entry_t entry)
483{
484 return 0;
485}
486
Andrea Arcangeli6d0a07e2016-05-12 15:42:25 -0700487#define reuse_swap_page(page, total_mapcount) \
488 (page_trans_huge_mapcount(page, total_mapcount) == 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489
Hugh Dickinsa2c43ee2009-01-06 14:39:36 -0800490static inline int try_to_free_swap(struct page *page)
Rik van Riel68a223942008-10-18 20:26:23 -0700491{
492 return 0;
493}
494
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495static inline swp_entry_t get_swap_page(void)
496{
497 swp_entry_t entry;
498 entry.val = 0;
499 return entry;
500}
501
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502#endif /* CONFIG_SWAP */
Vladimir Davydov6f2cb2f2016-01-20 15:03:05 -0800503
504#ifdef CONFIG_MEMCG
505static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
506{
Johannes Weiner4550c4e2016-05-05 16:22:03 -0700507 /* Cgroup2 doesn't have per-cgroup swappiness */
508 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
509 return vm_swappiness;
510
Vladimir Davydov6f2cb2f2016-01-20 15:03:05 -0800511 /* root ? */
512 if (mem_cgroup_disabled() || !memcg->css.parent)
513 return vm_swappiness;
514
515 return memcg->swappiness;
516}
517
518#else
519static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
520{
521 return vm_swappiness;
522}
523#endif
524
525#ifdef CONFIG_MEMCG_SWAP
526extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);
527extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);
528extern void mem_cgroup_uncharge_swap(swp_entry_t entry);
Vladimir Davydovd8b38432016-01-20 15:03:07 -0800529extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
Vladimir Davydov5ccc5ab2016-01-20 15:03:10 -0800530extern bool mem_cgroup_swap_full(struct page *page);
Vladimir Davydov6f2cb2f2016-01-20 15:03:05 -0800531#else
532static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
533{
534}
535
536static inline int mem_cgroup_try_charge_swap(struct page *page,
537 swp_entry_t entry)
538{
539 return 0;
540}
541
542static inline void mem_cgroup_uncharge_swap(swp_entry_t entry)
543{
544}
Vladimir Davydovd8b38432016-01-20 15:03:07 -0800545
546static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
547{
548 return get_nr_swap_pages();
549}
Vladimir Davydov5ccc5ab2016-01-20 15:03:10 -0800550
551static inline bool mem_cgroup_swap_full(struct page *page)
552{
553 return vm_swap_full();
554}
Vladimir Davydov6f2cb2f2016-01-20 15:03:05 -0800555#endif
556
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557#endif /* __KERNEL__*/
558#endif /* _LINUX_SWAP_H */