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
39 * Use some of the swap files numbers for other purposes. This
40 * is a convenient way to hook into the VM to trigger special
45 * NUMA node memory migration support
47 #ifdef CONFIG_MIGRATION
48 #define SWP_MIGRATION_NUM 2
49 #define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
50 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
52 #define SWP_MIGRATION_NUM 0
56 * Handling of hardware poisoned pages with memory corruption.
58 #ifdef CONFIG_MEMORY_FAILURE
59 #define SWP_HWPOISON_NUM 1
60 #define SWP_HWPOISON MAX_SWAPFILES
62 #define SWP_HWPOISON_NUM 0
65 #define MAX_SWAPFILES \
66 ((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)
69 * Magic header for a swap area. The first part of the union is
70 * what the swap magic looks like for the old (limited to 128MB)
71 * swap area format, the second part of the union adds - in the
72 * old reserved area - some extra information. Note that the first
73 * kilobyte is reserved for boot loader or disk label stuff...
75 * Having the magic at the end of the PAGE_SIZE makes detecting swap
76 * areas somewhat tricky on machines that support multiple page sizes.
77 * For 2.5 we'll probably want to move the magic to just beyond the
82 char reserved
[PAGE_SIZE
- 10];
83 char magic
[10]; /* SWAP-SPACE or SWAPSPACE2 */
86 char bootbits
[1024]; /* Space for disklabel etc. */
90 unsigned char sws_uuid
[16];
91 unsigned char sws_volume
[16];
97 /* A swap entry has to fit into a "unsigned long", as
98 * the entry is hidden in the "index" field of the
99 * swapper address space.
106 * current->reclaim_state points to one of these when a task is running
109 struct reclaim_state
{
110 unsigned long reclaimed_slab
;
115 struct address_space
;
117 struct writeback_control
;
121 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
122 * disk blocks. A list of swap extents maps the entire swapfile. (Where the
123 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
124 * from setup, they're handled identically.
126 * We always assume that blocks are of size PAGE_SIZE.
129 struct list_head list
;
132 sector_t start_block
;
136 * Max bad pages in the new format..
138 #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
139 #define MAX_SWAP_BADPAGES \
140 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
143 SWP_USED
= (1 << 0), /* is slot in swap_info[] used? */
144 SWP_WRITEOK
= (1 << 1), /* ok to write to this swap? */
145 SWP_DISCARDABLE
= (1 << 2), /* blkdev supports discard */
146 SWP_DISCARDING
= (1 << 3), /* now discarding a free cluster */
147 SWP_SOLIDSTATE
= (1 << 4), /* blkdev seeks are cheap */
148 SWP_CONTINUED
= (1 << 5), /* swap_map has count continuation */
149 /* add others here before... */
150 SWP_SCANNING
= (1 << 8), /* refcount in scan_swap_map */
153 #define SWAP_CLUSTER_MAX 32
155 #define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */
156 #define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */
157 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
158 #define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */
159 #define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */
162 * The in-memory structure used to track swap areas.
164 struct swap_info_struct
{
165 unsigned long flags
; /* SWP_USED etc: see above */
166 signed short prio
; /* swap priority of this type */
167 signed char type
; /* strange name for an index */
168 signed char next
; /* next type on the swap list */
169 struct file
*swap_file
;
170 struct block_device
*bdev
;
171 struct swap_extent first_swap_extent
;
172 struct swap_extent
*curr_swap_extent
;
173 unsigned char *swap_map
;
174 unsigned int lowest_bit
;
175 unsigned int highest_bit
;
176 unsigned int lowest_alloc
; /* while preparing discard cluster */
177 unsigned int highest_alloc
; /* while preparing discard cluster */
178 unsigned int cluster_next
;
179 unsigned int cluster_nr
;
182 unsigned int inuse_pages
;
183 unsigned int old_block_size
;
187 int head
; /* head of priority-ordered swapfile list */
188 int next
; /* swapfile to be used next */
191 /* Swap 50% full? Release swapcache more aggressively.. */
192 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
194 /* linux/mm/page_alloc.c */
195 extern unsigned long totalram_pages
;
196 extern unsigned long totalreserve_pages
;
197 extern unsigned int nr_free_buffer_pages(void);
198 extern unsigned int nr_free_pagecache_pages(void);
200 /* Definition of global_page_state not available yet */
201 #define nr_free_pages() global_page_state(NR_FREE_PAGES)
204 /* linux/mm/swap.c */
205 extern void __lru_cache_add(struct page
*, enum lru_list lru
);
206 extern void lru_cache_add_lru(struct page
*, enum lru_list lru
);
207 extern void activate_page(struct page
*);
208 extern void mark_page_accessed(struct page
*);
209 extern void lru_add_drain(void);
210 extern int lru_add_drain_all(void);
211 extern void rotate_reclaimable_page(struct page
*page
);
212 extern void swap_setup(void);
214 extern void add_page_to_unevictable_list(struct page
*page
);
217 * lru_cache_add: add a page to the page lists
218 * @page: the page to add
220 static inline void lru_cache_add_anon(struct page
*page
)
222 __lru_cache_add(page
, LRU_INACTIVE_ANON
);
225 static inline void lru_cache_add_active_anon(struct page
*page
)
227 __lru_cache_add(page
, LRU_ACTIVE_ANON
);
230 static inline void lru_cache_add_file(struct page
*page
)
232 __lru_cache_add(page
, LRU_INACTIVE_FILE
);
235 static inline void lru_cache_add_active_file(struct page
*page
)
237 __lru_cache_add(page
, LRU_ACTIVE_FILE
);
240 /* linux/mm/vmscan.c */
241 extern unsigned long try_to_free_pages(struct zonelist
*zonelist
, int order
,
242 gfp_t gfp_mask
, nodemask_t
*mask
);
243 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup
*mem
,
244 gfp_t gfp_mask
, bool noswap
,
245 unsigned int swappiness
);
246 extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup
*mem
,
247 gfp_t gfp_mask
, bool noswap
,
248 unsigned int swappiness
,
251 extern int __isolate_lru_page(struct page
*page
, int mode
, int file
);
252 extern unsigned long shrink_all_memory(unsigned long nr_pages
);
253 extern int vm_swappiness
;
254 extern int remove_mapping(struct address_space
*mapping
, struct page
*page
);
255 extern long vm_total_pages
;
258 extern int zone_reclaim_mode
;
259 extern int sysctl_min_unmapped_ratio
;
260 extern int sysctl_min_slab_ratio
;
261 extern int zone_reclaim(struct zone
*, gfp_t
, unsigned int);
263 #define zone_reclaim_mode 0
264 static inline int zone_reclaim(struct zone
*z
, gfp_t mask
, unsigned int order
)
270 extern int page_evictable(struct page
*page
, struct vm_area_struct
*vma
);
271 extern void scan_mapping_unevictable_pages(struct address_space
*);
273 extern unsigned long scan_unevictable_pages
;
274 extern int scan_unevictable_handler(struct ctl_table
*, int,
275 void __user
*, size_t *, loff_t
*);
276 extern int scan_unevictable_register_node(struct node
*node
);
277 extern void scan_unevictable_unregister_node(struct node
*node
);
279 extern int kswapd_run(int nid
);
280 extern void kswapd_stop(int nid
);
283 /* linux/mm/shmem.c */
284 extern int shmem_unuse(swp_entry_t entry
, struct page
*page
);
285 #endif /* CONFIG_MMU */
287 extern void swap_unplug_io_fn(struct backing_dev_info
*, struct page
*);
290 /* linux/mm/page_io.c */
291 extern int swap_readpage(struct page
*);
292 extern int swap_writepage(struct page
*page
, struct writeback_control
*wbc
);
293 extern void end_swap_bio_read(struct bio
*bio
, int err
);
295 /* linux/mm/swap_state.c */
296 extern struct address_space swapper_space
;
297 #define total_swapcache_pages swapper_space.nrpages
298 extern void show_swap_cache_info(void);
299 extern int add_to_swap(struct page
*);
300 extern int add_to_swap_cache(struct page
*, swp_entry_t
, gfp_t
);
301 extern void __delete_from_swap_cache(struct page
*);
302 extern void delete_from_swap_cache(struct page
*);
303 extern void free_page_and_swap_cache(struct page
*);
304 extern void free_pages_and_swap_cache(struct page
**, int);
305 extern struct page
*lookup_swap_cache(swp_entry_t
);
306 extern struct page
*read_swap_cache_async(swp_entry_t
, gfp_t
,
307 struct vm_area_struct
*vma
, unsigned long addr
);
308 extern struct page
*swapin_readahead(swp_entry_t
, gfp_t
,
309 struct vm_area_struct
*vma
, unsigned long addr
);
311 /* linux/mm/swapfile.c */
312 extern long nr_swap_pages
;
313 extern long total_swap_pages
;
314 extern void si_swapinfo(struct sysinfo
*);
315 extern swp_entry_t
get_swap_page(void);
316 extern swp_entry_t
get_swap_page_of_type(int);
317 extern int valid_swaphandles(swp_entry_t
, unsigned long *);
318 extern int add_swap_count_continuation(swp_entry_t
, gfp_t
);
319 extern int swap_duplicate(swp_entry_t
);
320 extern int swapcache_prepare(swp_entry_t
);
321 extern void swap_free(swp_entry_t
);
322 extern void swapcache_free(swp_entry_t
, struct page
*page
);
323 extern int free_swap_and_cache(swp_entry_t
);
324 extern int swap_type_of(dev_t
, sector_t
, struct block_device
**);
325 extern unsigned int count_swap_pages(int, int);
326 extern sector_t
map_swap_page(swp_entry_t
, struct block_device
**);
327 extern sector_t
swapdev_block(int, pgoff_t
);
328 extern int reuse_swap_page(struct page
*);
329 extern int try_to_free_swap(struct page
*);
330 struct backing_dev_info
;
332 /* linux/mm/thrash.c */
333 extern struct mm_struct
*swap_token_mm
;
334 extern void grab_swap_token(struct mm_struct
*);
335 extern void __put_swap_token(struct mm_struct
*);
337 static inline int has_swap_token(struct mm_struct
*mm
)
339 return (mm
== swap_token_mm
);
342 static inline void put_swap_token(struct mm_struct
*mm
)
344 if (has_swap_token(mm
))
345 __put_swap_token(mm
);
348 static inline void disable_swap_token(void)
350 put_swap_token(swap_token_mm
);
353 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
355 mem_cgroup_uncharge_swapcache(struct page
*page
, swp_entry_t ent
, bool swapout
);
358 mem_cgroup_uncharge_swapcache(struct page
*page
, swp_entry_t ent
, bool swapout
)
362 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
363 extern void mem_cgroup_uncharge_swap(swp_entry_t ent
);
365 static inline void mem_cgroup_uncharge_swap(swp_entry_t ent
)
370 #else /* CONFIG_SWAP */
372 #define nr_swap_pages 0L
373 #define total_swap_pages 0L
374 #define total_swapcache_pages 0UL
376 #define si_swapinfo(val) \
377 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
378 /* only sparc can not include linux/pagemap.h in this file
379 * so leave page_cache_release and release_pages undeclared... */
380 #define free_page_and_swap_cache(page) \
381 page_cache_release(page)
382 #define free_pages_and_swap_cache(pages, nr) \
383 release_pages((pages), (nr), 0);
385 static inline void show_swap_cache_info(void)
389 #define free_swap_and_cache(swp) is_migration_entry(swp)
390 #define swapcache_prepare(swp) is_migration_entry(swp)
392 static inline int add_swap_count_continuation(swp_entry_t swp
, gfp_t gfp_mask
)
397 static inline int swap_duplicate(swp_entry_t swp
)
402 static inline void swap_free(swp_entry_t swp
)
406 static inline void swapcache_free(swp_entry_t swp
, struct page
*page
)
410 static inline struct page
*swapin_readahead(swp_entry_t swp
, gfp_t gfp_mask
,
411 struct vm_area_struct
*vma
, unsigned long addr
)
416 static inline int swap_writepage(struct page
*p
, struct writeback_control
*wbc
)
421 static inline struct page
*lookup_swap_cache(swp_entry_t swp
)
426 static inline int add_to_swap(struct page
*page
)
431 static inline int add_to_swap_cache(struct page
*page
, swp_entry_t entry
,
437 static inline void __delete_from_swap_cache(struct page
*page
)
441 static inline void delete_from_swap_cache(struct page
*page
)
445 #define reuse_swap_page(page) (page_mapcount(page) == 1)
447 static inline int try_to_free_swap(struct page
*page
)
452 static inline swp_entry_t
get_swap_page(void)
459 /* linux/mm/thrash.c */
460 static inline void put_swap_token(struct mm_struct
*mm
)
464 static inline void grab_swap_token(struct mm_struct
*mm
)
468 static inline int has_swap_token(struct mm_struct
*mm
)
473 static inline void disable_swap_token(void)
478 mem_cgroup_uncharge_swapcache(struct page
*page
, swp_entry_t ent
)
482 #endif /* CONFIG_SWAP */
483 #endif /* __KERNEL__*/
484 #endif /* _LINUX_SWAP_H */