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