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 SWP_BLKDEV = (1 << 6), /* its a block device */
150 /* add others here before... */
151 SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
154 #define SWAP_CLUSTER_MAX 32
156 #define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */
157 #define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */
158 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
159 #define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */
160 #define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */
161 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */
164 * The in-memory structure used to track swap areas.
166 struct swap_info_struct {
167 unsigned long flags; /* SWP_USED etc: see above */
168 signed short prio; /* swap priority of this type */
169 signed char type; /* strange name for an index */
170 signed char next; /* next type on the swap list */
171 unsigned int max; /* extent of the swap_map */
172 unsigned char *swap_map; /* vmalloc'ed array of usage counts */
173 unsigned int lowest_bit; /* index of first free in swap_map */
174 unsigned int highest_bit; /* index of last free in swap_map */
175 unsigned int pages; /* total of usable pages of swap */
176 unsigned int inuse_pages; /* number of those currently in use */
177 unsigned int cluster_next; /* likely index for next allocation */
178 unsigned int cluster_nr; /* countdown to next cluster search */
179 unsigned int lowest_alloc; /* while preparing discard cluster */
180 unsigned int highest_alloc; /* while preparing discard cluster */
181 struct swap_extent *curr_swap_extent;
182 struct swap_extent first_swap_extent;
183 struct block_device *bdev; /* swap device or bdev of swap file */
184 struct file *swap_file; /* seldom referenced */
185 unsigned int old_block_size; /* seldom referenced */
189 int head; /* head of priority-ordered swapfile list */
190 int next; /* swapfile to be used next */
193 /* Swap 50% full? Release swapcache more aggressively.. */
194 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
196 /* linux/mm/page_alloc.c */
197 extern unsigned long totalram_pages;
198 extern unsigned long totalreserve_pages;
199 extern unsigned int nr_free_buffer_pages(void);
200 extern unsigned int nr_free_pagecache_pages(void);
202 /* Definition of global_page_state not available yet */
203 #define nr_free_pages() global_page_state(NR_FREE_PAGES)
206 /* linux/mm/swap.c */
207 extern void __lru_cache_add(struct page *, enum lru_list lru);
208 extern void lru_cache_add_lru(struct page *, enum lru_list lru);
209 extern void activate_page(struct page *);
210 extern void mark_page_accessed(struct page *);
211 extern void lru_add_drain(void);
212 extern int lru_add_drain_all(void);
213 extern void rotate_reclaimable_page(struct page *page);
214 extern void swap_setup(void);
216 extern void add_page_to_unevictable_list(struct page *page);
219 * lru_cache_add: add a page to the page lists
220 * @page: the page to add
222 static inline void lru_cache_add_anon(struct page *page)
224 __lru_cache_add(page, LRU_INACTIVE_ANON);
227 static inline void lru_cache_add_file(struct page *page)
229 __lru_cache_add(page, LRU_INACTIVE_FILE);
232 /* LRU Isolation modes. */
233 #define ISOLATE_INACTIVE 0 /* Isolate inactive pages. */
234 #define ISOLATE_ACTIVE 1 /* Isolate active pages. */
235 #define ISOLATE_BOTH 2 /* Isolate both active and inactive pages. */
237 /* linux/mm/vmscan.c */
238 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
239 gfp_t gfp_mask, nodemask_t *mask);
240 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
241 gfp_t gfp_mask, bool noswap,
242 unsigned int swappiness);
243 extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
244 gfp_t gfp_mask, bool noswap,
245 unsigned int swappiness,
248 extern int __isolate_lru_page(struct page *page, int mode, int file);
249 extern unsigned long shrink_all_memory(unsigned long nr_pages);
250 extern int vm_swappiness;
251 extern int remove_mapping(struct address_space *mapping, struct page *page);
252 extern long vm_total_pages;
255 extern int zone_reclaim_mode;
256 extern int sysctl_min_unmapped_ratio;
257 extern int sysctl_min_slab_ratio;
258 extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
260 #define zone_reclaim_mode 0
261 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
267 extern int page_evictable(struct page *page, struct vm_area_struct *vma);
268 extern void scan_mapping_unevictable_pages(struct address_space *);
270 extern unsigned long scan_unevictable_pages;
271 extern int scan_unevictable_handler(struct ctl_table *, int,
272 void __user *, size_t *, loff_t *);
273 extern int scan_unevictable_register_node(struct node *node);
274 extern void scan_unevictable_unregister_node(struct node *node);
276 extern int kswapd_run(int nid);
277 extern void kswapd_stop(int nid);
280 /* linux/mm/shmem.c */
281 extern int shmem_unuse(swp_entry_t entry, struct page *page);
282 #endif /* CONFIG_MMU */
284 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);
287 /* linux/mm/page_io.c */
288 extern int swap_readpage(struct page *);
289 extern int swap_writepage(struct page *page, struct writeback_control *wbc);
290 extern void end_swap_bio_read(struct bio *bio, int err);
292 /* linux/mm/swap_state.c */
293 extern struct address_space swapper_space;
294 #define total_swapcache_pages swapper_space.nrpages
295 extern void show_swap_cache_info(void);
296 extern int add_to_swap(struct page *);
297 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
298 extern void __delete_from_swap_cache(struct page *);
299 extern void delete_from_swap_cache(struct page *);
300 extern void free_page_and_swap_cache(struct page *);
301 extern void free_pages_and_swap_cache(struct page **, int);
302 extern struct page *lookup_swap_cache(swp_entry_t);
303 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
304 struct vm_area_struct *vma, unsigned long addr);
305 extern struct page *swapin_readahead(swp_entry_t, gfp_t,
306 struct vm_area_struct *vma, unsigned long addr);
308 /* linux/mm/swapfile.c */
309 extern long nr_swap_pages;
310 extern long total_swap_pages;
311 extern void si_swapinfo(struct sysinfo *);
312 extern swp_entry_t get_swap_page(void);
313 extern swp_entry_t get_swap_page_of_type(int);
314 extern int valid_swaphandles(swp_entry_t, unsigned long *);
315 extern int add_swap_count_continuation(swp_entry_t, gfp_t);
316 extern void swap_shmem_alloc(swp_entry_t);
317 extern int swap_duplicate(swp_entry_t);
318 extern int swapcache_prepare(swp_entry_t);
319 extern void swap_free(swp_entry_t);
320 extern void swapcache_free(swp_entry_t, struct page *page);
321 extern int free_swap_and_cache(swp_entry_t);
322 extern int swap_type_of(dev_t, sector_t, struct block_device **);
323 extern unsigned int count_swap_pages(int, int);
324 extern sector_t map_swap_page(struct page *, struct block_device **);
325 extern sector_t swapdev_block(int, pgoff_t);
326 extern int reuse_swap_page(struct page *);
327 extern int try_to_free_swap(struct page *);
328 struct backing_dev_info;
330 /* linux/mm/thrash.c */
331 extern struct mm_struct *swap_token_mm;
332 extern void grab_swap_token(struct mm_struct *);
333 extern void __put_swap_token(struct mm_struct *);
335 static inline int has_swap_token(struct mm_struct *mm)
337 return (mm == swap_token_mm);
340 static inline void put_swap_token(struct mm_struct *mm)
342 if (has_swap_token(mm))
343 __put_swap_token(mm);
346 static inline void disable_swap_token(void)
348 put_swap_token(swap_token_mm);
351 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
353 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout);
354 extern int mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep);
357 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
361 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
362 extern void mem_cgroup_uncharge_swap(swp_entry_t ent);
364 static inline void mem_cgroup_uncharge_swap(swp_entry_t ent)
369 #else /* CONFIG_SWAP */
371 #define nr_swap_pages 0L
372 #define total_swap_pages 0L
373 #define total_swapcache_pages 0UL
375 #define si_swapinfo(val) \
376 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
377 /* only sparc can not include linux/pagemap.h in this file
378 * so leave page_cache_release and release_pages undeclared... */
379 #define free_page_and_swap_cache(page) \
380 page_cache_release(page)
381 #define free_pages_and_swap_cache(pages, nr) \
382 release_pages((pages), (nr), 0);
384 static inline void show_swap_cache_info(void)
388 #define free_swap_and_cache(swp) is_migration_entry(swp)
389 #define swapcache_prepare(swp) is_migration_entry(swp)
391 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
396 static inline void swap_shmem_alloc(swp_entry_t swp)
400 static inline int swap_duplicate(swp_entry_t swp)
405 static inline void swap_free(swp_entry_t swp)
409 static inline void swapcache_free(swp_entry_t swp, struct page *page)
413 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
414 struct vm_area_struct *vma, unsigned long addr)
419 static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
424 static inline struct page *lookup_swap_cache(swp_entry_t swp)
429 static inline int add_to_swap(struct page *page)
434 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
440 static inline void __delete_from_swap_cache(struct page *page)
444 static inline void delete_from_swap_cache(struct page *page)
448 #define reuse_swap_page(page) (page_mapcount(page) == 1)
450 static inline int try_to_free_swap(struct page *page)
455 static inline swp_entry_t get_swap_page(void)
462 /* linux/mm/thrash.c */
463 static inline void put_swap_token(struct mm_struct *mm)
467 static inline void grab_swap_token(struct mm_struct *mm)
471 static inline int has_swap_token(struct mm_struct *mm)
476 static inline void disable_swap_token(void)
481 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
485 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
487 mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep)
493 #endif /* CONFIG_SWAP */
494 #endif /* __KERNEL__*/
495 #endif /* _LINUX_SWAP_H */