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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/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_ACTIVE = (SWP_USED | SWP_WRITEOK),
124 /* add others here before... */
125 SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
126};
127
128#define SWAP_CLUSTER_MAX 32
129
130#define SWAP_MAP_MAX 0x7fff
131#define SWAP_MAP_BAD 0x8000
132
133/*
134 * The in-memory structure used to track swap areas.
135 */
136struct swap_info_struct {
137 unsigned int flags;
138 int prio; /* swap priority */
139 struct file *swap_file;
140 struct block_device *bdev;
141 struct list_head extent_list;
142 struct swap_extent *curr_swap_extent;
143 unsigned old_block_size;
144 unsigned short * swap_map;
145 unsigned int lowest_bit;
146 unsigned int highest_bit;
147 unsigned int cluster_next;
148 unsigned int cluster_nr;
149 unsigned int pages;
150 unsigned int max;
151 unsigned int inuse_pages;
152 int next; /* next entry on swap list */
153};
154
155struct swap_list_t {
156 int head; /* head of priority-ordered swapfile list */
157 int next; /* swapfile to be used next */
158};
159
160/* Swap 50% full? Release swapcache more aggressively.. */
161#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
162
163/* linux/mm/page_alloc.c */
164extern unsigned long totalram_pages;
165extern unsigned long totalreserve_pages;
166extern long nr_swap_pages;
167extern unsigned int nr_free_buffer_pages(void);
168extern unsigned int nr_free_pagecache_pages(void);
169
170/* Definition of global_page_state not available yet */
171#define nr_free_pages() global_page_state(NR_FREE_PAGES)
172
173
174/* linux/mm/swap.c */
175extern void __lru_cache_add(struct page *, enum lru_list lru);
176extern void lru_cache_add_lru(struct page *, enum lru_list lru);
177extern void lru_cache_add_active_or_unevictable(struct page *,
178 struct vm_area_struct *);
179extern void activate_page(struct page *);
180extern void mark_page_accessed(struct page *);
181extern void lru_add_drain(void);
182extern int lru_add_drain_all(void);
183extern void rotate_reclaimable_page(struct page *page);
184extern void swap_setup(void);
185
186extern void add_page_to_unevictable_list(struct page *page);
187
188/**
189 * lru_cache_add: add a page to the page lists
190 * @page: the page to add
191 */
192static inline void lru_cache_add_anon(struct page *page)
193{
194 __lru_cache_add(page, LRU_INACTIVE_ANON);
195}
196
197static inline void lru_cache_add_active_anon(struct page *page)
198{
199 __lru_cache_add(page, LRU_ACTIVE_ANON);
200}
201
202static inline void lru_cache_add_file(struct page *page)
203{
204 __lru_cache_add(page, LRU_INACTIVE_FILE);
205}
206
207static inline void lru_cache_add_active_file(struct page *page)
208{
209 __lru_cache_add(page, LRU_ACTIVE_FILE);
210}
211
212/* linux/mm/vmscan.c */
213extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
214 gfp_t gfp_mask);
215extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
216 gfp_t gfp_mask);
217extern int __isolate_lru_page(struct page *page, int mode, int file);
218extern unsigned long shrink_all_memory(unsigned long nr_pages);
219extern int vm_swappiness;
220extern int remove_mapping(struct address_space *mapping, struct page *page);
221extern long vm_total_pages;
222
223#ifdef CONFIG_NUMA
224extern int zone_reclaim_mode;
225extern int sysctl_min_unmapped_ratio;
226extern int sysctl_min_slab_ratio;
227extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
228#else
229#define zone_reclaim_mode 0
230static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
231{
232 return 0;
233}
234#endif
235
236#ifdef CONFIG_UNEVICTABLE_LRU
237extern int page_evictable(struct page *page, struct vm_area_struct *vma);
238extern void scan_mapping_unevictable_pages(struct address_space *);
239
240extern unsigned long scan_unevictable_pages;
241extern int scan_unevictable_handler(struct ctl_table *, int, struct file *,
242 void __user *, size_t *, loff_t *);
243extern int scan_unevictable_register_node(struct node *node);
244extern void scan_unevictable_unregister_node(struct node *node);
245#else
246static inline int page_evictable(struct page *page,
247 struct vm_area_struct *vma)
248{
249 return 1;
250}
251
252static inline void scan_mapping_unevictable_pages(struct address_space *mapping)
253{
254}
255
256static inline int scan_unevictable_register_node(struct node *node)
257{
258 return 0;
259}
260
261static inline void scan_unevictable_unregister_node(struct node *node) { }
262#endif
263
264extern int kswapd_run(int nid);
265
266#ifdef CONFIG_MMU
267/* linux/mm/shmem.c */
268extern int shmem_unuse(swp_entry_t entry, struct page *page);
269#endif /* CONFIG_MMU */
270
271extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);
272
273#ifdef CONFIG_SWAP
274/* linux/mm/page_io.c */
275extern int swap_readpage(struct file *, struct page *);
276extern int swap_writepage(struct page *page, struct writeback_control *wbc);
277extern void end_swap_bio_read(struct bio *bio, int err);
278
279/* linux/mm/swap_state.c */
280extern struct address_space swapper_space;
281#define total_swapcache_pages swapper_space.nrpages
282extern void show_swap_cache_info(void);
283extern int add_to_swap(struct page *, gfp_t);
284extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
285extern void __delete_from_swap_cache(struct page *);
286extern void delete_from_swap_cache(struct page *);
287extern void free_page_and_swap_cache(struct page *);
288extern void free_pages_and_swap_cache(struct page **, int);
289extern struct page *lookup_swap_cache(swp_entry_t);
290extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
291 struct vm_area_struct *vma, unsigned long addr);
292extern struct page *swapin_readahead(swp_entry_t, gfp_t,
293 struct vm_area_struct *vma, unsigned long addr);
294
295/* linux/mm/swapfile.c */
296extern long total_swap_pages;
297extern void si_swapinfo(struct sysinfo *);
298extern swp_entry_t get_swap_page(void);
299extern swp_entry_t get_swap_page_of_type(int);
300extern int swap_duplicate(swp_entry_t);
301extern int valid_swaphandles(swp_entry_t, unsigned long *);
302extern void swap_free(swp_entry_t);
303extern void free_swap_and_cache(swp_entry_t);
304extern int swap_type_of(dev_t, sector_t, struct block_device **);
305extern unsigned int count_swap_pages(int, int);
306extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
307extern sector_t swapdev_block(int, pgoff_t);
308extern struct swap_info_struct *get_swap_info_struct(unsigned);
309extern int can_share_swap_page(struct page *);
310extern int remove_exclusive_swap_page(struct page *);
311extern int remove_exclusive_swap_page_ref(struct page *);
312struct backing_dev_info;
313
314/* linux/mm/thrash.c */
315extern struct mm_struct * swap_token_mm;
316extern void grab_swap_token(void);
317extern void __put_swap_token(struct mm_struct *);
318
319static inline int has_swap_token(struct mm_struct *mm)
320{
321 return (mm == swap_token_mm);
322}
323
324static inline void put_swap_token(struct mm_struct *mm)
325{
326 if (has_swap_token(mm))
327 __put_swap_token(mm);
328}
329
330static inline void disable_swap_token(void)
331{
332 put_swap_token(swap_token_mm);
333}
334
335#else /* CONFIG_SWAP */
336
337#define total_swap_pages 0
338#define total_swapcache_pages 0UL
339
340#define si_swapinfo(val) \
341 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
342/* only sparc can not include linux/pagemap.h in this file
343 * so leave page_cache_release and release_pages undeclared... */
344#define free_page_and_swap_cache(page) \
345 page_cache_release(page)
346#define free_pages_and_swap_cache(pages, nr) \
347 release_pages((pages), (nr), 0);
348
349static inline void show_swap_cache_info(void)
350{
351}
352
353static inline void free_swap_and_cache(swp_entry_t swp)
354{
355}
356
357static inline int swap_duplicate(swp_entry_t swp)
358{
359 return 0;
360}
361
362static inline void swap_free(swp_entry_t swp)
363{
364}
365
366static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
367 struct vm_area_struct *vma, unsigned long addr)
368{
369 return NULL;
370}
371
372static inline struct page *lookup_swap_cache(swp_entry_t swp)
373{
374 return NULL;
375}
376
377#define can_share_swap_page(p) (page_mapcount(p) == 1)
378
379static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
380 gfp_t gfp_mask)
381{
382 return -1;
383}
384
385static inline void __delete_from_swap_cache(struct page *page)
386{
387}
388
389static inline void delete_from_swap_cache(struct page *page)
390{
391}
392
393#define swap_token_default_timeout 0
394
395static inline int remove_exclusive_swap_page(struct page *p)
396{
397 return 0;
398}
399
400static inline int remove_exclusive_swap_page_ref(struct page *page)
401{
402 return 0;
403}
404
405static inline swp_entry_t get_swap_page(void)
406{
407 swp_entry_t entry;
408 entry.val = 0;
409 return entry;
410}
411
412/* linux/mm/thrash.c */
413#define put_swap_token(x) do { } while(0)
414#define grab_swap_token() do { } while(0)
415#define has_swap_token(x) 0
416#define disable_swap_token() do { } while(0)
417
418#endif /* CONFIG_SWAP */
419#endif /* __KERNEL__*/
420#endif /* _LINUX_SWAP_H */