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linux
1#ifndef _LINUX_SWAP_H
2#define _LINUX_SWAP_H
3
4#include <linux/spinlock.h>
5#include <linux/linkage.h>
6#include <linux/mmzone.h>
7#include <linux/list.h>
8#include <linux/memcontrol.h>
9#include <linux/sched.h>
10#include <linux/node.h>
11
12#include <asm/atomic.h>
13#include <asm/page.h>
14
15struct notifier_block;
16
17struct bio;
18
19#define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
20#define SWAP_FLAG_PRIO_MASK 0x7fff
21#define SWAP_FLAG_PRIO_SHIFT 0
22
23static inline int current_is_kswapd(void)
24{
25 return current->flags & PF_KSWAPD;
26}
27
28/*
29 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
30 * be swapped to. The swap type and the offset into that swap type are
31 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits
32 * for the type means that the maximum number of swapcache pages is 27 bits
33 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
34 * the type/offset into the pte as 5/27 as well.
35 */
36#define MAX_SWAPFILES_SHIFT 5
37#ifndef CONFIG_MIGRATION
38#define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
39#else
40/* Use last two entries for page migration swap entries */
41#define MAX_SWAPFILES ((1 << MAX_SWAPFILES_SHIFT)-2)
42#define SWP_MIGRATION_READ MAX_SWAPFILES
43#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + 1)
44#endif
45
46/*
47 * Magic header for a swap area. The first part of the union is
48 * what the swap magic looks like for the old (limited to 128MB)
49 * swap area format, the second part of the union adds - in the
50 * old reserved area - some extra information. Note that the first
51 * kilobyte is reserved for boot loader or disk label stuff...
52 *
53 * Having the magic at the end of the PAGE_SIZE makes detecting swap
54 * areas somewhat tricky on machines that support multiple page sizes.
55 * For 2.5 we'll probably want to move the magic to just beyond the
56 * bootbits...
57 */
58union swap_header {
59 struct {
60 char reserved[PAGE_SIZE - 10];
61 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
62 } magic;
63 struct {
64 char bootbits[1024]; /* Space for disklabel etc. */
65 __u32 version;
66 __u32 last_page;
67 __u32 nr_badpages;
68 unsigned char sws_uuid[16];
69 unsigned char sws_volume[16];
70 __u32 padding[117];
71 __u32 badpages[1];
72 } info;
73};
74
75 /* A swap entry has to fit into a "unsigned long", as
76 * the entry is hidden in the "index" field of the
77 * swapper address space.
78 */
79typedef struct {
80 unsigned long val;
81} swp_entry_t;
82
83/*
84 * current->reclaim_state points to one of these when a task is running
85 * memory reclaim
86 */
87struct reclaim_state {
88 unsigned long reclaimed_slab;
89};
90
91#ifdef __KERNEL__
92
93struct address_space;
94struct sysinfo;
95struct writeback_control;
96struct zone;
97
98/*
99 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
100 * disk blocks. A list of swap extents maps the entire swapfile. (Where the
101 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
102 * from setup, they're handled identically.
103 *
104 * We always assume that blocks are of size PAGE_SIZE.
105 */
106struct swap_extent {
107 struct list_head list;
108 pgoff_t start_page;
109 pgoff_t nr_pages;
110 sector_t start_block;
111};
112
113/*
114 * Max bad pages in the new format..
115 */
116#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
117#define MAX_SWAP_BADPAGES \
118 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
119
120enum {
121 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
122 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
123 SWP_DISCARDABLE = (1 << 2), /* blkdev supports discard */
124 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
125 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
126 /* add others here before... */
127 SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
128};
129
130#define SWAP_CLUSTER_MAX 32
131
132#define SWAP_MAP_MAX 0x7ffe
133#define SWAP_MAP_BAD 0x7fff
134#define SWAP_HAS_CACHE 0x8000 /* There is a swap cache of entry. */
135#define SWAP_COUNT_MASK (~SWAP_HAS_CACHE)
136/*
137 * The in-memory structure used to track swap areas.
138 */
139struct swap_info_struct {
140 unsigned long flags;
141 int prio; /* swap priority */
142 int next; /* next entry on swap list */
143 struct file *swap_file;
144 struct block_device *bdev;
145 struct list_head extent_list;
146 struct swap_extent *curr_swap_extent;
147 unsigned short *swap_map;
148 unsigned int lowest_bit;
149 unsigned int highest_bit;
150 unsigned int lowest_alloc; /* while preparing discard cluster */
151 unsigned int highest_alloc; /* while preparing discard cluster */
152 unsigned int cluster_next;
153 unsigned int cluster_nr;
154 unsigned int pages;
155 unsigned int max;
156 unsigned int inuse_pages;
157 unsigned int old_block_size;
158};
159
160struct swap_list_t {
161 int head; /* head of priority-ordered swapfile list */
162 int next; /* swapfile to be used next */
163};
164
165/* Swap 50% full? Release swapcache more aggressively.. */
166#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
167
168/* linux/mm/page_alloc.c */
169extern unsigned long totalram_pages;
170extern unsigned long totalreserve_pages;
171extern unsigned int nr_free_buffer_pages(void);
172extern unsigned int nr_free_pagecache_pages(void);
173
174/* Definition of global_page_state not available yet */
175#define nr_free_pages() global_page_state(NR_FREE_PAGES)
176
177
178/* linux/mm/swap.c */
179extern void __lru_cache_add(struct page *, enum lru_list lru);
180extern void lru_cache_add_lru(struct page *, enum lru_list lru);
181extern void activate_page(struct page *);
182extern void mark_page_accessed(struct page *);
183extern void lru_add_drain(void);
184extern int lru_add_drain_all(void);
185extern void rotate_reclaimable_page(struct page *page);
186extern void swap_setup(void);
187
188extern void add_page_to_unevictable_list(struct page *page);
189
190/**
191 * lru_cache_add: add a page to the page lists
192 * @page: the page to add
193 */
194static inline void lru_cache_add_anon(struct page *page)
195{
196 __lru_cache_add(page, LRU_INACTIVE_ANON);
197}
198
199static inline void lru_cache_add_active_anon(struct page *page)
200{
201 __lru_cache_add(page, LRU_ACTIVE_ANON);
202}
203
204static inline void lru_cache_add_file(struct page *page)
205{
206 __lru_cache_add(page, LRU_INACTIVE_FILE);
207}
208
209static inline void lru_cache_add_active_file(struct page *page)
210{
211 __lru_cache_add(page, LRU_ACTIVE_FILE);
212}
213
214/* linux/mm/vmscan.c */
215extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
216 gfp_t gfp_mask, nodemask_t *mask);
217extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
218 gfp_t gfp_mask, bool noswap,
219 unsigned int swappiness);
220extern int __isolate_lru_page(struct page *page, int mode, int file);
221extern unsigned long shrink_all_memory(unsigned long nr_pages);
222extern int vm_swappiness;
223extern int remove_mapping(struct address_space *mapping, struct page *page);
224extern long vm_total_pages;
225
226#ifdef CONFIG_NUMA
227extern int zone_reclaim_mode;
228extern int sysctl_min_unmapped_ratio;
229extern int sysctl_min_slab_ratio;
230extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
231#else
232#define zone_reclaim_mode 0
233static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
234{
235 return 0;
236}
237#endif
238
239extern int page_evictable(struct page *page, struct vm_area_struct *vma);
240extern void scan_mapping_unevictable_pages(struct address_space *);
241
242extern unsigned long scan_unevictable_pages;
243extern int scan_unevictable_handler(struct ctl_table *, int, struct file *,
244 void __user *, size_t *, loff_t *);
245extern int scan_unevictable_register_node(struct node *node);
246extern void scan_unevictable_unregister_node(struct node *node);
247
248extern int kswapd_run(int nid);
249
250#ifdef CONFIG_MMU
251/* linux/mm/shmem.c */
252extern int shmem_unuse(swp_entry_t entry, struct page *page);
253#endif /* CONFIG_MMU */
254
255extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);
256
257#ifdef CONFIG_SWAP
258/* linux/mm/page_io.c */
259extern int swap_readpage(struct page *);
260extern int swap_writepage(struct page *page, struct writeback_control *wbc);
261extern void end_swap_bio_read(struct bio *bio, int err);
262
263/* linux/mm/swap_state.c */
264extern struct address_space swapper_space;
265#define total_swapcache_pages swapper_space.nrpages
266extern void show_swap_cache_info(void);
267extern int add_to_swap(struct page *);
268extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
269extern void __delete_from_swap_cache(struct page *);
270extern void delete_from_swap_cache(struct page *);
271extern void free_page_and_swap_cache(struct page *);
272extern void free_pages_and_swap_cache(struct page **, int);
273extern struct page *lookup_swap_cache(swp_entry_t);
274extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
275 struct vm_area_struct *vma, unsigned long addr);
276extern struct page *swapin_readahead(swp_entry_t, gfp_t,
277 struct vm_area_struct *vma, unsigned long addr);
278
279/* linux/mm/swapfile.c */
280extern long nr_swap_pages;
281extern long total_swap_pages;
282extern void si_swapinfo(struct sysinfo *);
283extern swp_entry_t get_swap_page(void);
284extern swp_entry_t get_swap_page_of_type(int);
285extern void swap_duplicate(swp_entry_t);
286extern int swapcache_prepare(swp_entry_t);
287extern int valid_swaphandles(swp_entry_t, unsigned long *);
288extern void swap_free(swp_entry_t);
289extern void swapcache_free(swp_entry_t, struct page *page);
290extern int free_swap_and_cache(swp_entry_t);
291extern int swap_type_of(dev_t, sector_t, struct block_device **);
292extern unsigned int count_swap_pages(int, int);
293extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
294extern sector_t swapdev_block(int, pgoff_t);
295extern struct swap_info_struct *get_swap_info_struct(unsigned);
296extern int reuse_swap_page(struct page *);
297extern int try_to_free_swap(struct page *);
298struct backing_dev_info;
299
300/* linux/mm/thrash.c */
301extern struct mm_struct *swap_token_mm;
302extern void grab_swap_token(struct mm_struct *);
303extern void __put_swap_token(struct mm_struct *);
304
305static inline int has_swap_token(struct mm_struct *mm)
306{
307 return (mm == swap_token_mm);
308}
309
310static inline void put_swap_token(struct mm_struct *mm)
311{
312 if (has_swap_token(mm))
313 __put_swap_token(mm);
314}
315
316static inline void disable_swap_token(void)
317{
318 put_swap_token(swap_token_mm);
319}
320
321#ifdef CONFIG_CGROUP_MEM_RES_CTLR
322extern void
323mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout);
324#else
325static inline void
326mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
327{
328}
329#endif
330#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
331extern void mem_cgroup_uncharge_swap(swp_entry_t ent);
332#else
333static inline void mem_cgroup_uncharge_swap(swp_entry_t ent)
334{
335}
336#endif
337
338#else /* CONFIG_SWAP */
339
340#define nr_swap_pages 0L
341#define total_swap_pages 0L
342#define total_swapcache_pages 0UL
343
344#define si_swapinfo(val) \
345 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
346/* only sparc can not include linux/pagemap.h in this file
347 * so leave page_cache_release and release_pages undeclared... */
348#define free_page_and_swap_cache(page) \
349 page_cache_release(page)
350#define free_pages_and_swap_cache(pages, nr) \
351 release_pages((pages), (nr), 0);
352
353static inline void show_swap_cache_info(void)
354{
355}
356
357#define free_swap_and_cache(swp) is_migration_entry(swp)
358#define swapcache_prepare(swp) is_migration_entry(swp)
359
360static inline void swap_duplicate(swp_entry_t swp)
361{
362}
363
364static inline void swap_free(swp_entry_t swp)
365{
366}
367
368static inline void swapcache_free(swp_entry_t swp, struct page *page)
369{
370}
371
372static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
373 struct vm_area_struct *vma, unsigned long addr)
374{
375 return NULL;
376}
377
378static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
379{
380 return 0;
381}
382
383static inline struct page *lookup_swap_cache(swp_entry_t swp)
384{
385 return NULL;
386}
387
388static inline int add_to_swap(struct page *page)
389{
390 return 0;
391}
392
393static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
394 gfp_t gfp_mask)
395{
396 return -1;
397}
398
399static inline void __delete_from_swap_cache(struct page *page)
400{
401}
402
403static inline void delete_from_swap_cache(struct page *page)
404{
405}
406
407#define reuse_swap_page(page) (page_mapcount(page) == 1)
408
409static inline int try_to_free_swap(struct page *page)
410{
411 return 0;
412}
413
414static inline swp_entry_t get_swap_page(void)
415{
416 swp_entry_t entry;
417 entry.val = 0;
418 return entry;
419}
420
421/* linux/mm/thrash.c */
422#define put_swap_token(mm) do { } while (0)
423#define grab_swap_token(mm) do { } while (0)
424#define has_swap_token(mm) 0
425#define disable_swap_token() do { } while (0)
426
427static inline void
428mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
429{
430}
431
432#endif /* CONFIG_SWAP */
433#endif /* __KERNEL__*/
434#endif /* _LINUX_SWAP_H */