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_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 */
130 #define SWAP_CLUSTER_MAX 32
132 #define SWAP_MAP_MAX 0x7fff
133 #define SWAP_MAP_BAD 0x8000
136 * The in-memory structure used to track swap areas.
138 struct swap_info_struct
{
140 int prio
; /* swap priority */
141 int next
; /* next entry on swap list */
142 struct file
*swap_file
;
143 struct block_device
*bdev
;
144 struct list_head extent_list
;
145 struct swap_extent
*curr_swap_extent
;
146 unsigned short *swap_map
;
147 unsigned int lowest_bit
;
148 unsigned int highest_bit
;
149 unsigned int lowest_alloc
; /* while preparing discard cluster */
150 unsigned int highest_alloc
; /* while preparing discard cluster */
151 unsigned int cluster_next
;
152 unsigned int cluster_nr
;
155 unsigned int inuse_pages
;
156 unsigned int old_block_size
;
160 int head
; /* head of priority-ordered swapfile list */
161 int next
; /* swapfile to be used next */
164 /* Swap 50% full? Release swapcache more aggressively.. */
165 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
167 /* linux/mm/page_alloc.c */
168 extern unsigned long totalram_pages
;
169 extern unsigned long totalreserve_pages
;
170 extern unsigned int nr_free_buffer_pages(void);
171 extern unsigned int nr_free_pagecache_pages(void);
173 /* Definition of global_page_state not available yet */
174 #define nr_free_pages() global_page_state(NR_FREE_PAGES)
177 /* linux/mm/swap.c */
178 extern void __lru_cache_add(struct page
*, enum lru_list lru
);
179 extern void lru_cache_add_lru(struct page
*, enum lru_list lru
);
180 extern void activate_page(struct page
*);
181 extern void mark_page_accessed(struct page
*);
182 extern void lru_add_drain(void);
183 extern int lru_add_drain_all(void);
184 extern void rotate_reclaimable_page(struct page
*page
);
185 extern void swap_setup(void);
187 extern void add_page_to_unevictable_list(struct page
*page
);
190 * lru_cache_add: add a page to the page lists
191 * @page: the page to add
193 static inline void lru_cache_add_anon(struct page
*page
)
195 __lru_cache_add(page
, LRU_INACTIVE_ANON
);
198 static inline void lru_cache_add_active_anon(struct page
*page
)
200 __lru_cache_add(page
, LRU_ACTIVE_ANON
);
203 static inline void lru_cache_add_file(struct page
*page
)
205 __lru_cache_add(page
, LRU_INACTIVE_FILE
);
208 static inline void lru_cache_add_active_file(struct page
*page
)
210 __lru_cache_add(page
, LRU_ACTIVE_FILE
);
213 /* linux/mm/vmscan.c */
214 extern unsigned long try_to_free_pages(struct zonelist
*zonelist
, int order
,
216 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup
*mem
,
217 gfp_t gfp_mask
, bool noswap
);
218 extern int __isolate_lru_page(struct page
*page
, int mode
, int file
);
219 extern unsigned long shrink_all_memory(unsigned long nr_pages
);
220 extern int vm_swappiness
;
221 extern int remove_mapping(struct address_space
*mapping
, struct page
*page
);
222 extern long vm_total_pages
;
225 extern int zone_reclaim_mode
;
226 extern int sysctl_min_unmapped_ratio
;
227 extern int sysctl_min_slab_ratio
;
228 extern int zone_reclaim(struct zone
*, gfp_t
, unsigned int);
230 #define zone_reclaim_mode 0
231 static inline int zone_reclaim(struct zone
*z
, gfp_t mask
, unsigned int order
)
237 #ifdef CONFIG_UNEVICTABLE_LRU
238 extern int page_evictable(struct page
*page
, struct vm_area_struct
*vma
);
239 extern void scan_mapping_unevictable_pages(struct address_space
*);
241 extern unsigned long scan_unevictable_pages
;
242 extern int scan_unevictable_handler(struct ctl_table
*, int, struct file
*,
243 void __user
*, size_t *, loff_t
*);
244 extern int scan_unevictable_register_node(struct node
*node
);
245 extern void scan_unevictable_unregister_node(struct node
*node
);
247 static inline int page_evictable(struct page
*page
,
248 struct vm_area_struct
*vma
)
253 static inline void scan_mapping_unevictable_pages(struct address_space
*mapping
)
257 static inline int scan_unevictable_register_node(struct node
*node
)
262 static inline void scan_unevictable_unregister_node(struct node
*node
) { }
265 extern int kswapd_run(int nid
);
268 /* linux/mm/shmem.c */
269 extern int shmem_unuse(swp_entry_t entry
, struct page
*page
);
270 #endif /* CONFIG_MMU */
272 extern void swap_unplug_io_fn(struct backing_dev_info
*, struct page
*);
275 /* linux/mm/page_io.c */
276 extern int swap_readpage(struct file
*, struct page
*);
277 extern int swap_writepage(struct page
*page
, struct writeback_control
*wbc
);
278 extern void end_swap_bio_read(struct bio
*bio
, int err
);
280 /* linux/mm/swap_state.c */
281 extern struct address_space swapper_space
;
282 #define total_swapcache_pages swapper_space.nrpages
283 extern void show_swap_cache_info(void);
284 extern int add_to_swap(struct page
*);
285 extern int add_to_swap_cache(struct page
*, swp_entry_t
, gfp_t
);
286 extern void __delete_from_swap_cache(struct page
*);
287 extern void delete_from_swap_cache(struct page
*);
288 extern void free_page_and_swap_cache(struct page
*);
289 extern void free_pages_and_swap_cache(struct page
**, int);
290 extern struct page
*lookup_swap_cache(swp_entry_t
);
291 extern struct page
*read_swap_cache_async(swp_entry_t
, gfp_t
,
292 struct vm_area_struct
*vma
, unsigned long addr
);
293 extern struct page
*swapin_readahead(swp_entry_t
, gfp_t
,
294 struct vm_area_struct
*vma
, unsigned long addr
);
296 /* linux/mm/swapfile.c */
297 extern long nr_swap_pages
;
298 extern long total_swap_pages
;
299 extern void si_swapinfo(struct sysinfo
*);
300 extern swp_entry_t
get_swap_page(void);
301 extern swp_entry_t
get_swap_page_of_type(int);
302 extern int swap_duplicate(swp_entry_t
);
303 extern int valid_swaphandles(swp_entry_t
, unsigned long *);
304 extern void swap_free(swp_entry_t
);
305 extern int free_swap_and_cache(swp_entry_t
);
306 extern int swap_type_of(dev_t
, sector_t
, struct block_device
**);
307 extern unsigned int count_swap_pages(int, int);
308 extern sector_t
map_swap_page(struct swap_info_struct
*, pgoff_t
);
309 extern sector_t
swapdev_block(int, pgoff_t
);
310 extern struct swap_info_struct
*get_swap_info_struct(unsigned);
311 extern int reuse_swap_page(struct page
*);
312 extern int try_to_free_swap(struct page
*);
313 struct backing_dev_info
;
315 /* linux/mm/thrash.c */
316 extern struct mm_struct
* swap_token_mm
;
317 extern void grab_swap_token(void);
318 extern void __put_swap_token(struct mm_struct
*);
320 static inline int has_swap_token(struct mm_struct
*mm
)
322 return (mm
== swap_token_mm
);
325 static inline void put_swap_token(struct mm_struct
*mm
)
327 if (has_swap_token(mm
))
328 __put_swap_token(mm
);
331 static inline void disable_swap_token(void)
333 put_swap_token(swap_token_mm
);
336 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
337 extern int mem_cgroup_cache_charge_swapin(struct page
*page
,
338 struct mm_struct
*mm
, gfp_t mask
, bool locked
);
339 extern void mem_cgroup_uncharge_swapcache(struct page
*page
, swp_entry_t ent
);
342 int mem_cgroup_cache_charge_swapin(struct page
*page
,
343 struct mm_struct
*mm
, gfp_t mask
, bool locked
)
348 mem_cgroup_uncharge_swapcache(struct page
*page
, swp_entry_t ent
)
352 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
353 extern void mem_cgroup_uncharge_swap(swp_entry_t ent
);
355 static inline void mem_cgroup_uncharge_swap(swp_entry_t ent
)
360 #else /* CONFIG_SWAP */
362 #define nr_swap_pages 0L
363 #define total_swap_pages 0L
364 #define total_swapcache_pages 0UL
366 #define si_swapinfo(val) \
367 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
368 /* only sparc can not include linux/pagemap.h in this file
369 * so leave page_cache_release and release_pages undeclared... */
370 #define free_page_and_swap_cache(page) \
371 page_cache_release(page)
372 #define free_pages_and_swap_cache(pages, nr) \
373 release_pages((pages), (nr), 0);
375 static inline void show_swap_cache_info(void)
379 #define free_swap_and_cache(swp) is_migration_entry(swp)
380 #define swap_duplicate(swp) is_migration_entry(swp)
382 static inline void swap_free(swp_entry_t swp
)
386 static inline struct page
*swapin_readahead(swp_entry_t swp
, gfp_t gfp_mask
,
387 struct vm_area_struct
*vma
, unsigned long addr
)
392 static inline struct page
*lookup_swap_cache(swp_entry_t swp
)
397 static inline int add_to_swap(struct page
*page
)
402 static inline int add_to_swap_cache(struct page
*page
, swp_entry_t entry
,
408 static inline void __delete_from_swap_cache(struct page
*page
)
412 static inline void delete_from_swap_cache(struct page
*page
)
416 #define reuse_swap_page(page) (page_mapcount(page) == 1)
418 static inline int try_to_free_swap(struct page
*page
)
423 static inline swp_entry_t
get_swap_page(void)
430 /* linux/mm/thrash.c */
431 #define put_swap_token(x) do { } while(0)
432 #define grab_swap_token() do { } while(0)
433 #define has_swap_token(x) 0
434 #define disable_swap_token() do { } while(0)
436 static inline int mem_cgroup_cache_charge_swapin(struct page
*page
,
437 struct mm_struct
*mm
, gfp_t mask
, bool locked
)
442 #endif /* CONFIG_SWAP */
443 #endif /* __KERNEL__*/
444 #endif /* _LINUX_SWAP_H */