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>
12 #include <asm/atomic.h>
15 struct notifier_block;
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
23 static inline int current_is_kswapd(void)
25 return current->flags & PF_KSWAPD;
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.
36 #define MAX_SWAPFILES_SHIFT 5
37 #ifndef CONFIG_MIGRATION
38 #define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
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)
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...
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
60 char reserved[PAGE_SIZE - 10];
61 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
64 char bootbits[1024]; /* Space for disklabel etc. */
68 unsigned char sws_uuid[16];
69 unsigned char sws_volume[16];
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.
84 * current->reclaim_state points to one of these when a task is running
87 struct reclaim_state {
88 unsigned long reclaimed_slab;
95 struct writeback_control;
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.
104 * We always assume that blocks are of size PAGE_SIZE.
107 struct list_head list;
110 sector_t start_block;
114 * Max bad pages in the new format..
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))
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 */
128 #define SWAP_CLUSTER_MAX 32
130 #define SWAP_MAP_MAX 0x7fff
131 #define SWAP_MAP_BAD 0x8000
134 * The in-memory structure used to track swap areas.
136 struct swap_info_struct {
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;
151 unsigned int inuse_pages;
152 int next; /* next entry on swap list */
156 int head; /* head of priority-ordered swapfile list */
157 int next; /* swapfile to be used next */
160 /* Swap 50% full? Release swapcache more aggressively.. */
161 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
163 /* linux/mm/page_alloc.c */
164 extern unsigned long totalram_pages;
165 extern unsigned long totalreserve_pages;
166 extern long nr_swap_pages;
167 extern unsigned int nr_free_buffer_pages(void);
168 extern unsigned int nr_free_pagecache_pages(void);
170 /* Definition of global_page_state not available yet */
171 #define nr_free_pages() global_page_state(NR_FREE_PAGES)
174 /* linux/mm/swap.c */
175 extern void __lru_cache_add(struct page *, enum lru_list lru);
176 extern void lru_cache_add_lru(struct page *, enum lru_list lru);
177 extern void activate_page(struct page *);
178 extern void mark_page_accessed(struct page *);
179 extern void lru_add_drain(void);
180 extern int lru_add_drain_all(void);
181 extern void rotate_reclaimable_page(struct page *page);
182 extern void swap_setup(void);
184 extern void add_page_to_unevictable_list(struct page *page);
187 * lru_cache_add: add a page to the page lists
188 * @page: the page to add
190 static inline void lru_cache_add_anon(struct page *page)
192 __lru_cache_add(page, LRU_INACTIVE_ANON);
195 static inline void lru_cache_add_active_anon(struct page *page)
197 __lru_cache_add(page, LRU_ACTIVE_ANON);
200 static inline void lru_cache_add_file(struct page *page)
202 __lru_cache_add(page, LRU_INACTIVE_FILE);
205 static inline void lru_cache_add_active_file(struct page *page)
207 __lru_cache_add(page, LRU_ACTIVE_FILE);
210 /* linux/mm/vmscan.c */
211 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
213 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
215 extern int __isolate_lru_page(struct page *page, int mode, int file);
216 extern unsigned long shrink_all_memory(unsigned long nr_pages);
217 extern int vm_swappiness;
218 extern int remove_mapping(struct address_space *mapping, struct page *page);
219 extern long vm_total_pages;
222 extern int zone_reclaim_mode;
223 extern int sysctl_min_unmapped_ratio;
224 extern int sysctl_min_slab_ratio;
225 extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
227 #define zone_reclaim_mode 0
228 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
234 #ifdef CONFIG_UNEVICTABLE_LRU
235 extern int page_evictable(struct page *page, struct vm_area_struct *vma);
236 extern void scan_mapping_unevictable_pages(struct address_space *);
238 extern unsigned long scan_unevictable_pages;
239 extern int scan_unevictable_handler(struct ctl_table *, int, struct file *,
240 void __user *, size_t *, loff_t *);
241 extern int scan_unevictable_register_node(struct node *node);
242 extern void scan_unevictable_unregister_node(struct node *node);
244 static inline int page_evictable(struct page *page,
245 struct vm_area_struct *vma)
250 static inline void scan_mapping_unevictable_pages(struct address_space *mapping)
254 static inline int scan_unevictable_register_node(struct node *node)
259 static inline void scan_unevictable_unregister_node(struct node *node) { }
262 extern int kswapd_run(int nid);
265 /* linux/mm/shmem.c */
266 extern int shmem_unuse(swp_entry_t entry, struct page *page);
267 #endif /* CONFIG_MMU */
269 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);
272 /* linux/mm/page_io.c */
273 extern int swap_readpage(struct file *, struct page *);
274 extern int swap_writepage(struct page *page, struct writeback_control *wbc);
275 extern void end_swap_bio_read(struct bio *bio, int err);
277 /* linux/mm/swap_state.c */
278 extern struct address_space swapper_space;
279 #define total_swapcache_pages swapper_space.nrpages
280 extern void show_swap_cache_info(void);
281 extern int add_to_swap(struct page *, gfp_t);
282 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
283 extern void __delete_from_swap_cache(struct page *);
284 extern void delete_from_swap_cache(struct page *);
285 extern void free_page_and_swap_cache(struct page *);
286 extern void free_pages_and_swap_cache(struct page **, int);
287 extern struct page *lookup_swap_cache(swp_entry_t);
288 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
289 struct vm_area_struct *vma, unsigned long addr);
290 extern struct page *swapin_readahead(swp_entry_t, gfp_t,
291 struct vm_area_struct *vma, unsigned long addr);
293 /* linux/mm/swapfile.c */
294 extern long total_swap_pages;
295 extern void si_swapinfo(struct sysinfo *);
296 extern swp_entry_t get_swap_page(void);
297 extern swp_entry_t get_swap_page_of_type(int);
298 extern int swap_duplicate(swp_entry_t);
299 extern int valid_swaphandles(swp_entry_t, unsigned long *);
300 extern void swap_free(swp_entry_t);
301 extern void free_swap_and_cache(swp_entry_t);
302 extern int swap_type_of(dev_t, sector_t, struct block_device **);
303 extern unsigned int count_swap_pages(int, int);
304 extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
305 extern sector_t swapdev_block(int, pgoff_t);
306 extern struct swap_info_struct *get_swap_info_struct(unsigned);
307 extern int can_share_swap_page(struct page *);
308 extern int remove_exclusive_swap_page(struct page *);
309 extern int remove_exclusive_swap_page_ref(struct page *);
310 struct backing_dev_info;
312 /* linux/mm/thrash.c */
313 extern struct mm_struct * swap_token_mm;
314 extern void grab_swap_token(void);
315 extern void __put_swap_token(struct mm_struct *);
317 static inline int has_swap_token(struct mm_struct *mm)
319 return (mm == swap_token_mm);
322 static inline void put_swap_token(struct mm_struct *mm)
324 if (has_swap_token(mm))
325 __put_swap_token(mm);
328 static inline void disable_swap_token(void)
330 put_swap_token(swap_token_mm);
333 #else /* CONFIG_SWAP */
335 #define total_swap_pages 0
336 #define total_swapcache_pages 0UL
338 #define si_swapinfo(val) \
339 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
340 /* only sparc can not include linux/pagemap.h in this file
341 * so leave page_cache_release and release_pages undeclared... */
342 #define free_page_and_swap_cache(page) \
343 page_cache_release(page)
344 #define free_pages_and_swap_cache(pages, nr) \
345 release_pages((pages), (nr), 0);
347 static inline void show_swap_cache_info(void)
351 static inline void free_swap_and_cache(swp_entry_t swp)
355 static inline int swap_duplicate(swp_entry_t swp)
360 static inline void swap_free(swp_entry_t swp)
364 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
365 struct vm_area_struct *vma, unsigned long addr)
370 static inline struct page *lookup_swap_cache(swp_entry_t swp)
375 #define can_share_swap_page(p) (page_mapcount(p) == 1)
377 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
383 static inline void __delete_from_swap_cache(struct page *page)
387 static inline void delete_from_swap_cache(struct page *page)
391 #define swap_token_default_timeout 0
393 static inline int remove_exclusive_swap_page(struct page *p)
398 static inline int remove_exclusive_swap_page_ref(struct page *page)
403 static inline swp_entry_t get_swap_page(void)
410 /* linux/mm/thrash.c */
411 #define put_swap_token(x) do { } while(0)
412 #define grab_swap_token() do { } while(0)
413 #define has_swap_token(x) 0
414 #define disable_swap_token() do { } while(0)
416 #endif /* CONFIG_SWAP */
417 #endif /* __KERNEL__*/
418 #endif /* _LINUX_SWAP_H */