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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 */
Hugh Dickins52b7efdb2005-09-03 15:54:39 -0700153 /* add others here before... */
Rafael Aquinidcf6b7d2013-07-03 15:02:46 -0700154 SWP_SCANNING = (1 << 10), /* refcount in scan_swap_map */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155};
156
Johannes Weinerd778df52013-02-22 16:32:12 -0800157#define SWAP_CLUSTER_MAX 32UL
Mel Gorman748446b2010-05-24 14:32:27 -0700158#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159
Mel Gorman8afdcec2011-03-22 16:33:04 -0700160/*
Jianyu Zhan4be89a32014-06-04 16:10:38 -0700161 * Ratio between zone->managed_pages and the "gap" that above the per-zone
162 * "high_wmark". While balancing nodes, We allow kswapd to shrink zones that
163 * do not meet the (high_wmark + gap) watermark, even which already met the
164 * high_wmark, in order to provide better per-zone lru behavior. We are ok to
Mel Gorman8afdcec2011-03-22 16:33:04 -0700165 * spend not more than 1% of the memory for this zone balancing "gap".
166 */
167#define KSWAPD_ZONE_BALANCE_GAP_RATIO 100
168
Hugh Dickins570a335b2009-12-14 17:58:46 -0800169#define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */
170#define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */
171#define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
172#define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */
173#define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */
Hugh Dickinsaaa46862009-12-14 17:58:47 -0800174#define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */
Hugh Dickins253d5532009-12-14 17:58:44 -0800175
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176/*
Shaohua Li2a8f9442013-09-11 14:20:28 -0700177 * We use this to track usage of a cluster. A cluster is a block of swap disk
178 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All
179 * free clusters are organized into a list. We fetch an entry from the list to
180 * get a free cluster.
181 *
182 * The data field stores next cluster if the cluster is free or cluster usage
183 * counter otherwise. The flags field determines if a cluster is free. This is
184 * protected by swap_info_struct.lock.
185 */
186struct swap_cluster_info {
187 unsigned int data:24;
188 unsigned int flags:8;
189};
190#define CLUSTER_FLAG_FREE 1 /* This cluster is free */
191#define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */
192
193/*
Shaohua Liebc2a1a2013-09-11 14:20:32 -0700194 * We assign a cluster to each CPU, so each CPU can allocate swap entry from
195 * its own cluster and swapout sequentially. The purpose is to optimize swapout
196 * throughput.
197 */
198struct percpu_cluster {
199 struct swap_cluster_info index; /* Current cluster index */
200 unsigned int next; /* Likely next allocation offset */
201};
202
203/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 * The in-memory structure used to track swap areas.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 */
206struct swap_info_struct {
Hugh Dickinsefa90a92009-12-14 17:58:41 -0800207 unsigned long flags; /* SWP_USED etc: see above */
208 signed short prio; /* swap priority of this type */
Dan Streetman18ab4d42014-06-04 16:09:59 -0700209 struct plist_node list; /* entry in swap_active_head */
210 struct plist_node avail_list; /* entry in swap_avail_head */
Hugh Dickinsefa90a92009-12-14 17:58:41 -0800211 signed char type; /* strange name for an index */
Hugh Dickins75097652009-12-14 17:58:48 -0800212 unsigned int max; /* extent of the swap_map */
213 unsigned char *swap_map; /* vmalloc'ed array of usage counts */
Shaohua Li2a8f9442013-09-11 14:20:28 -0700214 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
215 struct swap_cluster_info free_cluster_head; /* free cluster list head */
216 struct swap_cluster_info free_cluster_tail; /* free cluster list tail */
Hugh Dickins75097652009-12-14 17:58:48 -0800217 unsigned int lowest_bit; /* index of first free in swap_map */
218 unsigned int highest_bit; /* index of last free in swap_map */
219 unsigned int pages; /* total of usable pages of swap */
220 unsigned int inuse_pages; /* number of those currently in use */
221 unsigned int cluster_next; /* likely index for next allocation */
222 unsigned int cluster_nr; /* countdown to next cluster search */
Shaohua Liebc2a1a2013-09-11 14:20:32 -0700223 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
Hugh Dickins75097652009-12-14 17:58:48 -0800224 struct swap_extent *curr_swap_extent;
225 struct swap_extent first_swap_extent;
226 struct block_device *bdev; /* swap device or bdev of swap file */
227 struct file *swap_file; /* seldom referenced */
228 unsigned int old_block_size; /* seldom referenced */
Dan Magenheimer38b5faf2012-04-09 17:08:06 -0600229#ifdef CONFIG_FRONTSWAP
230 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */
231 atomic_t frontswap_pages; /* frontswap pages in-use counter */
232#endif
Shaohua Liec8acf22013-02-22 16:34:38 -0800233 spinlock_t lock; /*
234 * protect map scan related fields like
235 * swap_map, lowest_bit, highest_bit,
236 * inuse_pages, cluster_next,
Shaohua Li815c2c52013-09-11 14:20:30 -0700237 * cluster_nr, lowest_alloc,
238 * highest_alloc, free/discard cluster
239 * list. other fields are only changed
240 * at swapon/swapoff, so are protected
241 * by swap_lock. changing flags need
242 * hold this lock and swap_lock. If
243 * both locks need hold, hold swap_lock
244 * first.
Shaohua Liec8acf22013-02-22 16:34:38 -0800245 */
Shaohua Li815c2c52013-09-11 14:20:30 -0700246 struct work_struct discard_work; /* discard worker */
247 struct swap_cluster_info discard_cluster_head; /* list head of discard clusters */
248 struct swap_cluster_info discard_cluster_tail; /* list tail of discard clusters */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249};
250
Johannes Weinera5289102014-04-03 14:47:51 -0700251/* linux/mm/workingset.c */
252void *workingset_eviction(struct address_space *mapping, struct page *page);
253bool workingset_refault(void *shadow);
254void workingset_activation(struct page *page);
Johannes Weiner449dd692014-04-03 14:47:56 -0700255extern struct list_lru workingset_shadow_nodes;
256
257static inline unsigned int workingset_node_pages(struct radix_tree_node *node)
258{
259 return node->count & RADIX_TREE_COUNT_MASK;
260}
261
262static inline void workingset_node_pages_inc(struct radix_tree_node *node)
263{
264 node->count++;
265}
266
267static inline void workingset_node_pages_dec(struct radix_tree_node *node)
268{
269 node->count--;
270}
271
272static inline unsigned int workingset_node_shadows(struct radix_tree_node *node)
273{
274 return node->count >> RADIX_TREE_COUNT_SHIFT;
275}
276
277static inline void workingset_node_shadows_inc(struct radix_tree_node *node)
278{
279 node->count += 1U << RADIX_TREE_COUNT_SHIFT;
280}
281
282static inline void workingset_node_shadows_dec(struct radix_tree_node *node)
283{
284 node->count -= 1U << RADIX_TREE_COUNT_SHIFT;
285}
Johannes Weinera5289102014-04-03 14:47:51 -0700286
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287/* linux/mm/page_alloc.c */
288extern unsigned long totalram_pages;
Hideo AOKIcb45b0e2006-04-10 22:52:59 -0700289extern unsigned long totalreserve_pages;
Johannes Weinerab8fabd2012-01-10 15:07:42 -0800290extern unsigned long dirty_balance_reserve;
Zhang Yanfeiebec3862013-02-22 16:35:43 -0800291extern unsigned long nr_free_buffer_pages(void);
292extern unsigned long nr_free_pagecache_pages(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
Christoph Lameter96177292007-02-10 01:43:03 -0800294/* Definition of global_page_state not available yet */
295#define nr_free_pages() global_page_state(NR_FREE_PAGES)
296
297
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298/* linux/mm/swap.c */
Mel Gormanc53954a2013-07-03 15:02:34 -0700299extern void lru_cache_add(struct page *);
Jianyu Zhan2329d372014-06-04 16:07:31 -0700300extern void lru_cache_add_anon(struct page *page);
301extern void lru_cache_add_file(struct page *page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -0700302extern void lru_add_page_tail(struct page *page, struct page *page_tail,
Shaohua Li5bc7b8a2013-04-29 15:08:36 -0700303 struct lruvec *lruvec, struct list_head *head);
Harvey Harrisonb3c97522008-02-13 15:03:15 -0800304extern void activate_page(struct page *);
305extern void mark_page_accessed(struct page *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306extern void lru_add_drain(void);
Konstantin Khlebnikovf0cb3c72012-03-21 16:34:06 -0700307extern void lru_add_drain_cpu(int cpu);
Chris Metcalf5fbc4612013-09-12 15:13:55 -0700308extern void lru_add_drain_all(void);
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700309extern void rotate_reclaimable_page(struct page *page);
Minchan Kimcc5993b2015-04-15 16:13:26 -0700310extern void deactivate_file_page(struct page *page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311extern void swap_setup(void);
312
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700313extern void add_page_to_unevictable_list(struct page *page);
314
Johannes Weiner00501b52014-08-08 14:19:20 -0700315extern void lru_cache_add_active_or_unevictable(struct page *page,
316 struct vm_area_struct *vma);
317
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318/* linux/mm/vmscan.c */
Mel Gormandac1d272008-04-28 02:12:12 -0700319extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
KAMEZAWA Hiroyuki327c0e92009-03-31 15:23:31 -0700320 gfp_t gfp_mask, nodemask_t *mask);
Konstantin Khlebnikovf3fd4a62012-05-29 15:06:54 -0700321extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
Johannes Weinerb70a2a22014-10-09 15:28:56 -0700322extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
323 unsigned long nr_pages,
324 gfp_t gfp_mask,
325 bool may_swap);
Johannes Weiner185efc02011-09-14 16:21:58 -0700326extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
327 gfp_t gfp_mask, bool noswap,
328 struct zone *zone,
329 unsigned long *nr_scanned);
Andrew Morton69e05942006-03-22 00:08:19 -0800330extern unsigned long shrink_all_memory(unsigned long nr_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331extern int vm_swappiness;
Christoph Lameterb20a3502006-03-22 00:09:12 -0800332extern int remove_mapping(struct address_space *mapping, struct page *page);
Zhang Yanfeib21e0b92013-02-22 16:35:48 -0800333extern unsigned long vm_total_pages;
Christoph Lameterb20a3502006-03-22 00:09:12 -0800334
Christoph Lameter9eeff232006-01-18 17:42:31 -0800335#ifdef CONFIG_NUMA
336extern int zone_reclaim_mode;
Christoph Lameter96146342006-07-03 00:24:13 -0700337extern int sysctl_min_unmapped_ratio;
Christoph Lameter0ff38492006-09-25 23:31:52 -0700338extern int sysctl_min_slab_ratio;
Christoph Lameter9eeff232006-01-18 17:42:31 -0800339extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
340#else
341#define zone_reclaim_mode 0
342static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
343{
344 return 0;
345}
346#endif
347
Hugh Dickins39b5f292012-10-08 16:33:18 -0700348extern int page_evictable(struct page *page);
Hugh Dickins24513262012-01-20 14:34:21 -0800349extern void check_move_unevictable_pages(struct page **, int nr_pages);
Lee Schermerhornaf936a12008-10-18 20:26:53 -0700350
Yasunori Goto3218ae12006-06-27 02:53:33 -0700351extern int kswapd_run(int nid);
David Rientjes8fe23e02009-12-14 17:58:33 -0800352extern void kswapd_stop(int nid);
Andrew Mortonc255a452012-07-31 16:43:02 -0700353#ifdef CONFIG_MEMCG
Michal Hocko33398cf2015-09-08 15:01:02 -0700354static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
355{
356 /* root ? */
357 if (mem_cgroup_disabled() || !memcg->css.parent)
358 return vm_swappiness;
359
360 return memcg->swappiness;
361}
362
KAMEZAWA Hiroyuki1f4c0252011-07-26 16:08:21 -0700363#else
364static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
365{
366 return vm_swappiness;
367}
368#endif
Andrew Mortonc255a452012-07-31 16:43:02 -0700369#ifdef CONFIG_MEMCG_SWAP
Johannes Weiner0a31bc92014-08-08 14:19:22 -0700370extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);
371extern void mem_cgroup_uncharge_swap(swp_entry_t entry);
Michal Hockodac23b02012-04-05 14:25:16 -0700372#else
Johannes Weiner0a31bc92014-08-08 14:19:22 -0700373static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
374{
375}
376static inline void mem_cgroup_uncharge_swap(swp_entry_t entry)
Michal Hockodac23b02012-04-05 14:25:16 -0700377{
378}
379#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380#ifdef CONFIG_SWAP
381/* linux/mm/page_io.c */
Minchan Kimaca8bf32009-06-16 15:33:02 -0700382extern int swap_readpage(struct page *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383extern int swap_writepage(struct page *page, struct writeback_control *wbc);
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200384extern void end_swap_bio_write(struct bio *bio);
Seth Jennings1eec6702013-04-29 15:08:35 -0700385extern int __swap_writepage(struct page *page, struct writeback_control *wbc,
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200386 bio_end_io_t end_write_func);
Mel Gorman62c230b2012-07-31 16:44:55 -0700387extern int swap_set_page_dirty(struct page *page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388
Mel Gormana509bc12012-07-31 16:44:57 -0700389int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
390 unsigned long nr_pages, sector_t start_block);
391int generic_swapfile_activate(struct swap_info_struct *, struct file *,
392 sector_t *);
393
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394/* linux/mm/swap_state.c */
Shaohua Li33806f02013-02-22 16:34:37 -0800395extern struct address_space swapper_spaces[];
396#define swap_address_space(entry) (&swapper_spaces[swp_type(entry)])
397extern unsigned long total_swapcache_pages(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398extern void show_swap_cache_info(void);
Shaohua Li5bc7b8a2013-04-29 15:08:36 -0700399extern int add_to_swap(struct page *, struct list_head *list);
Hugh Dickins73b12622008-02-04 22:28:50 -0800400extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
Seth Jennings2f772e62013-04-29 15:08:34 -0700401extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402extern void __delete_from_swap_cache(struct page *);
403extern void delete_from_swap_cache(struct page *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404extern void free_page_and_swap_cache(struct page *);
405extern void free_pages_and_swap_cache(struct page **, int);
Hugh Dickins46017e92008-02-04 22:28:41 -0800406extern struct page *lookup_swap_cache(swp_entry_t);
Hugh Dickins02098fe2008-02-04 22:28:42 -0800407extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
Hugh Dickins46017e92008-02-04 22:28:41 -0800408 struct vm_area_struct *vma, unsigned long addr);
Dmitry Safonov5b999aa2015-09-08 15:05:00 -0700409extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t,
410 struct vm_area_struct *vma, unsigned long addr,
411 bool *new_page_allocated);
Hugh Dickins02098fe2008-02-04 22:28:42 -0800412extern struct page *swapin_readahead(swp_entry_t, gfp_t,
Hugh Dickins46017e92008-02-04 22:28:41 -0800413 struct vm_area_struct *vma, unsigned long addr);
414
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415/* linux/mm/swapfile.c */
Shaohua Liec8acf22013-02-22 16:34:38 -0800416extern atomic_long_t nr_swap_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417extern long total_swap_pages;
Shaohua Liec8acf22013-02-22 16:34:38 -0800418
419/* Swap 50% full? Release swapcache more aggressively.. */
420static inline bool vm_swap_full(void)
421{
422 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
423}
424
425static inline long get_nr_swap_pages(void)
426{
427 return atomic_long_read(&nr_swap_pages);
428}
429
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430extern void si_swapinfo(struct sysinfo *);
431extern swp_entry_t get_swap_page(void);
Hugh Dickins910321e2010-09-09 16:38:07 -0700432extern swp_entry_t get_swap_page_of_type(int);
Hugh Dickins570a335b2009-12-14 17:58:46 -0800433extern int add_swap_count_continuation(swp_entry_t, gfp_t);
Hugh Dickinsaaa46862009-12-14 17:58:47 -0800434extern void swap_shmem_alloc(swp_entry_t);
Hugh Dickins570a335b2009-12-14 17:58:46 -0800435extern int swap_duplicate(swp_entry_t);
436extern int swapcache_prepare(swp_entry_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437extern void swap_free(swp_entry_t);
Johannes Weiner0a31bc92014-08-08 14:19:22 -0700438extern void swapcache_free(swp_entry_t);
Hugh Dickins2509ef22009-01-06 14:40:10 -0800439extern int free_swap_and_cache(swp_entry_t);
Rafael J. Wysocki7bf23682007-01-05 16:36:28 -0800440extern int swap_type_of(dev_t, sector_t, struct block_device **);
Rafael J. Wysockif577eb32006-03-23 02:59:59 -0800441extern unsigned int count_swap_pages(int, int);
Lee Schermerhornd4906e12009-12-14 17:58:49 -0800442extern sector_t map_swap_page(struct page *, struct block_device **);
Rafael J. Wysocki3aef83e2006-12-06 20:34:10 -0800443extern sector_t swapdev_block(int, pgoff_t);
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700444extern int page_swapcount(struct page *);
Minchan Kim8334b962015-09-08 15:00:24 -0700445extern int swp_swapcount(swp_entry_t entry);
Mel Gormanf981c592012-07-31 16:44:47 -0700446extern struct swap_info_struct *page_swap_info(struct page *);
Hugh Dickins7b1fe592009-01-06 14:39:34 -0800447extern int reuse_swap_page(struct page *);
Hugh Dickinsa2c43ee2009-01-06 14:39:36 -0800448extern int try_to_free_swap(struct page *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449struct backing_dev_info;
450
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451#else /* CONFIG_SWAP */
452
Joonsoo Kimd2cf5ad2013-09-11 14:21:29 -0700453#define swap_address_space(entry) (NULL)
Shaohua Liec8acf22013-02-22 16:34:38 -0800454#define get_nr_swap_pages() 0L
Hugh Dickinsb9627162009-01-06 14:39:41 -0800455#define total_swap_pages 0L
Shaohua Li33806f02013-02-22 16:34:37 -0800456#define total_swapcache_pages() 0UL
Shaohua Liec8acf22013-02-22 16:34:38 -0800457#define vm_swap_full() 0
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458
459#define si_swapinfo(val) \
460 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
Olaf Hering9ae5b3c2005-08-07 09:42:24 -0700461/* only sparc can not include linux/pagemap.h in this file
462 * so leave page_cache_release and release_pages undeclared... */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463#define free_page_and_swap_cache(page) \
464 page_cache_release(page)
465#define free_pages_and_swap_cache(pages, nr) \
Mel Gormanb745bc82014-06-04 16:10:22 -0700466 release_pages((pages), (nr), false);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467
Con Kolivasbd96b9e2006-06-23 02:03:42 -0700468static inline void show_swap_cache_info(void)
469{
470}
471
Hugh Dickins2509ef22009-01-06 14:40:10 -0800472#define free_swap_and_cache(swp) is_migration_entry(swp)
KAMEZAWA Hiroyukicb4b86b2009-06-16 15:32:52 -0700473#define swapcache_prepare(swp) is_migration_entry(swp)
Con Kolivasbd96b9e2006-06-23 02:03:42 -0700474
Hugh Dickins570a335b2009-12-14 17:58:46 -0800475static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
KAMEZAWA Hiroyuki355cfa72009-06-16 15:32:53 -0700476{
Hugh Dickins570a335b2009-12-14 17:58:46 -0800477 return 0;
478}
479
Hugh Dickinsaaa46862009-12-14 17:58:47 -0800480static inline void swap_shmem_alloc(swp_entry_t swp)
481{
482}
483
Hugh Dickins570a335b2009-12-14 17:58:46 -0800484static inline int swap_duplicate(swp_entry_t swp)
485{
486 return 0;
KAMEZAWA Hiroyuki355cfa72009-06-16 15:32:53 -0700487}
488
Con Kolivasbd96b9e2006-06-23 02:03:42 -0700489static inline void swap_free(swp_entry_t swp)
490{
491}
492
Johannes Weiner0a31bc92014-08-08 14:19:22 -0700493static inline void swapcache_free(swp_entry_t swp)
KAMEZAWA Hiroyukicb4b86b2009-06-16 15:32:52 -0700494{
495}
496
Hugh Dickins02098fe2008-02-04 22:28:42 -0800497static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
Con Kolivasbd96b9e2006-06-23 02:03:42 -0700498 struct vm_area_struct *vma, unsigned long addr)
499{
500 return NULL;
501}
502
Hugh Dickins9fab5612009-03-31 15:23:33 -0700503static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
504{
505 return 0;
506}
507
Con Kolivasbd96b9e2006-06-23 02:03:42 -0700508static inline struct page *lookup_swap_cache(swp_entry_t swp)
509{
510 return NULL;
511}
512
Shaohua Li5bc7b8a2013-04-29 15:08:36 -0700513static inline int add_to_swap(struct page *page, struct list_head *list)
Hugh Dickins60371d92009-01-06 14:39:40 -0800514{
515 return 0;
516}
517
Hugh Dickins73b12622008-02-04 22:28:50 -0800518static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
519 gfp_t gfp_mask)
Con Kolivasbd96b9e2006-06-23 02:03:42 -0700520{
Hugh Dickins73b12622008-02-04 22:28:50 -0800521 return -1;
Con Kolivasbd96b9e2006-06-23 02:03:42 -0700522}
523
524static inline void __delete_from_swap_cache(struct page *page)
525{
526}
527
528static inline void delete_from_swap_cache(struct page *page)
529{
530}
531
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700532static inline int page_swapcount(struct page *page)
533{
534 return 0;
535}
536
Minchan Kim8334b962015-09-08 15:00:24 -0700537static inline int swp_swapcount(swp_entry_t entry)
538{
539 return 0;
540}
541
Hugh Dickins7b1fe592009-01-06 14:39:34 -0800542#define reuse_swap_page(page) (page_mapcount(page) == 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543
Hugh Dickinsa2c43ee2009-01-06 14:39:36 -0800544static inline int try_to_free_swap(struct page *page)
Rik van Riel68a223942008-10-18 20:26:23 -0700545{
546 return 0;
547}
548
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549static inline swp_entry_t get_swap_page(void)
550{
551 swp_entry_t entry;
552 entry.val = 0;
553 return entry;
554}
555
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556#endif /* CONFIG_SWAP */
557#endif /* __KERNEL__*/
558#endif /* _LINUX_SWAP_H */