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