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
22 #define SWAP_FLAG_DISCARD 0x10000 /* discard swap cluster after use */
24 static inline int current_is_kswapd(void)
26 return current->flags & PF_KSWAPD;
30 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
31 * be swapped to. The swap type and the offset into that swap type are
32 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits
33 * for the type means that the maximum number of swapcache pages is 27 bits
34 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
35 * the type/offset into the pte as 5/27 as well.
37 #define MAX_SWAPFILES_SHIFT 5
40 * Use some of the swap files numbers for other purposes. This
41 * is a convenient way to hook into the VM to trigger special
46 * NUMA node memory migration support
48 #ifdef CONFIG_MIGRATION
49 #define SWP_MIGRATION_NUM 2
50 #define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
51 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
53 #define SWP_MIGRATION_NUM 0
57 * Handling of hardware poisoned pages with memory corruption.
59 #ifdef CONFIG_MEMORY_FAILURE
60 #define SWP_HWPOISON_NUM 1
61 #define SWP_HWPOISON MAX_SWAPFILES
63 #define SWP_HWPOISON_NUM 0
66 #define MAX_SWAPFILES \
67 ((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)
70 * Magic header for a swap area. The first part of the union is
71 * what the swap magic looks like for the old (limited to 128MB)
72 * swap area format, the second part of the union adds - in the
73 * old reserved area - some extra information. Note that the first
74 * kilobyte is reserved for boot loader or disk label stuff...
76 * Having the magic at the end of the PAGE_SIZE makes detecting swap
77 * areas somewhat tricky on machines that support multiple page sizes.
78 * For 2.5 we'll probably want to move the magic to just beyond the
83 char reserved[PAGE_SIZE - 10];
84 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
87 char bootbits[1024]; /* Space for disklabel etc. */
91 unsigned char sws_uuid[16];
92 unsigned char sws_volume[16];
98 /* A swap entry has to fit into a "unsigned long", as
99 * the entry is hidden in the "index" field of the
100 * swapper address space.
107 * current->reclaim_state points to one of these when a task is running
110 struct reclaim_state {
111 unsigned long reclaimed_slab;
116 struct address_space;
118 struct writeback_control;
122 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
123 * disk blocks. A list of swap extents maps the entire swapfile. (Where the
124 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
125 * from setup, they're handled identically.
127 * We always assume that blocks are of size PAGE_SIZE.
130 struct list_head list;
133 sector_t start_block;
137 * Max bad pages in the new format..
139 #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
140 #define MAX_SWAP_BADPAGES \
141 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
144 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
145 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
146 SWP_DISCARDABLE = (1 << 2), /* swapon+blkdev support discard */
147 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
148 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
149 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
150 SWP_BLKDEV = (1 << 6), /* its a block device */
151 /* add others here before... */
152 SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
155 #define SWAP_CLUSTER_MAX 32
156 #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
159 * Ratio between the present memory in the zone and the "gap" that
160 * we're allowing kswapd to shrink in addition to the per-zone high
161 * wmark, even for zones that already have the high wmark satisfied,
162 * in order to provide better per-zone lru behavior. We are ok to
163 * spend not more than 1% of the memory for this zone balancing "gap".
165 #define KSWAPD_ZONE_BALANCE_GAP_RATIO 100
167 #define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */
168 #define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */
169 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
170 #define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */
171 #define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */
172 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */
175 * The in-memory structure used to track swap areas.
177 struct swap_info_struct {
178 unsigned long flags; /* SWP_USED etc: see above */
179 signed short prio; /* swap priority of this type */
180 signed char type; /* strange name for an index */
181 signed char next; /* next type on the swap list */
182 unsigned int max; /* extent of the swap_map */
183 unsigned char *swap_map; /* vmalloc'ed array of usage counts */
184 unsigned int lowest_bit; /* index of first free in swap_map */
185 unsigned int highest_bit; /* index of last free in swap_map */
186 unsigned int pages; /* total of usable pages of swap */
187 unsigned int inuse_pages; /* number of those currently in use */
188 unsigned int cluster_next; /* likely index for next allocation */
189 unsigned int cluster_nr; /* countdown to next cluster search */
190 unsigned int lowest_alloc; /* while preparing discard cluster */
191 unsigned int highest_alloc; /* while preparing discard cluster */
192 struct swap_extent *curr_swap_extent;
193 struct swap_extent first_swap_extent;
194 struct block_device *bdev; /* swap device or bdev of swap file */
195 struct file *swap_file; /* seldom referenced */
196 unsigned int old_block_size; /* seldom referenced */
200 int head; /* head of priority-ordered swapfile list */
201 int next; /* swapfile to be used next */
204 /* Swap 50% full? Release swapcache more aggressively.. */
205 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
207 /* linux/mm/page_alloc.c */
208 extern unsigned long totalram_pages;
209 extern unsigned long totalreserve_pages;
210 extern unsigned int nr_free_buffer_pages(void);
211 extern unsigned int nr_free_pagecache_pages(void);
213 /* Definition of global_page_state not available yet */
214 #define nr_free_pages() global_page_state(NR_FREE_PAGES)
217 /* linux/mm/swap.c */
218 extern void __lru_cache_add(struct page *, enum lru_list lru);
219 extern void lru_cache_add_lru(struct page *, enum lru_list lru);
220 extern void lru_add_page_tail(struct zone* zone,
221 struct page *page, struct page *page_tail);
222 extern void activate_page(struct page *);
223 extern void mark_page_accessed(struct page *);
224 extern void lru_add_drain(void);
225 extern int lru_add_drain_all(void);
226 extern void rotate_reclaimable_page(struct page *page);
227 extern void deactivate_page(struct page *page);
228 extern void swap_setup(void);
230 extern void add_page_to_unevictable_list(struct page *page);
233 * lru_cache_add: add a page to the page lists
234 * @page: the page to add
236 static inline void lru_cache_add_anon(struct page *page)
238 __lru_cache_add(page, LRU_INACTIVE_ANON);
241 static inline void lru_cache_add_file(struct page *page)
243 __lru_cache_add(page, LRU_INACTIVE_FILE);
246 /* LRU Isolation modes. */
247 #define ISOLATE_INACTIVE 0 /* Isolate inactive pages. */
248 #define ISOLATE_ACTIVE 1 /* Isolate active pages. */
249 #define ISOLATE_BOTH 2 /* Isolate both active and inactive pages. */
251 /* linux/mm/vmscan.c */
252 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
253 gfp_t gfp_mask, nodemask_t *mask);
254 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
255 gfp_t gfp_mask, bool noswap,
256 unsigned int swappiness);
257 extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
258 gfp_t gfp_mask, bool noswap,
259 unsigned int swappiness,
261 unsigned long *nr_scanned);
262 extern int __isolate_lru_page(struct page *page, int mode, int file);
263 extern unsigned long shrink_all_memory(unsigned long nr_pages);
264 extern int vm_swappiness;
265 extern int remove_mapping(struct address_space *mapping, struct page *page);
266 extern long vm_total_pages;
269 extern int zone_reclaim_mode;
270 extern int sysctl_min_unmapped_ratio;
271 extern int sysctl_min_slab_ratio;
272 extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
274 #define zone_reclaim_mode 0
275 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
281 extern int page_evictable(struct page *page, struct vm_area_struct *vma);
282 extern void scan_mapping_unevictable_pages(struct address_space *);
284 extern unsigned long scan_unevictable_pages;
285 extern int scan_unevictable_handler(struct ctl_table *, int,
286 void __user *, size_t *, loff_t *);
288 extern int scan_unevictable_register_node(struct node *node);
289 extern void scan_unevictable_unregister_node(struct node *node);
291 static inline int scan_unevictable_register_node(struct node *node)
295 static inline void scan_unevictable_unregister_node(struct node *node)
300 extern int kswapd_run(int nid);
301 extern void kswapd_stop(int nid);
304 /* linux/mm/page_io.c */
305 extern int swap_readpage(struct page *);
306 extern int swap_writepage(struct page *page, struct writeback_control *wbc);
307 extern void end_swap_bio_read(struct bio *bio, int err);
309 /* linux/mm/swap_state.c */
310 extern struct address_space swapper_space;
311 #define total_swapcache_pages swapper_space.nrpages
312 extern void show_swap_cache_info(void);
313 extern int add_to_swap(struct page *);
314 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
315 extern void __delete_from_swap_cache(struct page *);
316 extern void delete_from_swap_cache(struct page *);
317 extern void free_page_and_swap_cache(struct page *);
318 extern void free_pages_and_swap_cache(struct page **, int);
319 extern struct page *lookup_swap_cache(swp_entry_t);
320 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
321 struct vm_area_struct *vma, unsigned long addr);
322 extern struct page *swapin_readahead(swp_entry_t, gfp_t,
323 struct vm_area_struct *vma, unsigned long addr);
325 /* linux/mm/swapfile.c */
326 extern long nr_swap_pages;
327 extern long total_swap_pages;
328 extern void si_swapinfo(struct sysinfo *);
329 extern swp_entry_t get_swap_page(void);
330 extern swp_entry_t get_swap_page_of_type(int);
331 extern int valid_swaphandles(swp_entry_t, unsigned long *);
332 extern int add_swap_count_continuation(swp_entry_t, gfp_t);
333 extern void swap_shmem_alloc(swp_entry_t);
334 extern int swap_duplicate(swp_entry_t);
335 extern int swapcache_prepare(swp_entry_t);
336 extern void swap_free(swp_entry_t);
337 extern void swapcache_free(swp_entry_t, struct page *page);
338 extern int free_swap_and_cache(swp_entry_t);
339 extern int swap_type_of(dev_t, sector_t, struct block_device **);
340 extern unsigned int count_swap_pages(int, int);
341 extern sector_t map_swap_page(struct page *, struct block_device **);
342 extern sector_t swapdev_block(int, pgoff_t);
343 extern int reuse_swap_page(struct page *);
344 extern int try_to_free_swap(struct page *);
345 struct backing_dev_info;
347 /* linux/mm/thrash.c */
348 extern struct mm_struct *swap_token_mm;
349 extern void grab_swap_token(struct mm_struct *);
350 extern void __put_swap_token(struct mm_struct *);
351 extern void disable_swap_token(struct mem_cgroup *memcg);
353 static inline int has_swap_token(struct mm_struct *mm)
355 return (mm == swap_token_mm);
358 static inline void put_swap_token(struct mm_struct *mm)
360 if (has_swap_token(mm))
361 __put_swap_token(mm);
364 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
366 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout);
367 extern int mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep);
370 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
374 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
375 extern void mem_cgroup_uncharge_swap(swp_entry_t ent);
377 static inline void mem_cgroup_uncharge_swap(swp_entry_t ent)
382 #else /* CONFIG_SWAP */
384 #define nr_swap_pages 0L
385 #define total_swap_pages 0L
386 #define total_swapcache_pages 0UL
388 #define si_swapinfo(val) \
389 do { (val)->freeswap = (val)->totalswap = 0; } while (0)
390 /* only sparc can not include linux/pagemap.h in this file
391 * so leave page_cache_release and release_pages undeclared... */
392 #define free_page_and_swap_cache(page) \
393 page_cache_release(page)
394 #define free_pages_and_swap_cache(pages, nr) \
395 release_pages((pages), (nr), 0);
397 static inline void show_swap_cache_info(void)
401 #define free_swap_and_cache(swp) is_migration_entry(swp)
402 #define swapcache_prepare(swp) is_migration_entry(swp)
404 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
409 static inline void swap_shmem_alloc(swp_entry_t swp)
413 static inline int swap_duplicate(swp_entry_t swp)
418 static inline void swap_free(swp_entry_t swp)
422 static inline void swapcache_free(swp_entry_t swp, struct page *page)
426 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
427 struct vm_area_struct *vma, unsigned long addr)
432 static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
437 static inline struct page *lookup_swap_cache(swp_entry_t swp)
442 static inline int add_to_swap(struct page *page)
447 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
453 static inline void __delete_from_swap_cache(struct page *page)
457 static inline void delete_from_swap_cache(struct page *page)
461 #define reuse_swap_page(page) (page_mapcount(page) == 1)
463 static inline int try_to_free_swap(struct page *page)
468 static inline swp_entry_t get_swap_page(void)
475 /* linux/mm/thrash.c */
476 static inline void put_swap_token(struct mm_struct *mm)
480 static inline void grab_swap_token(struct mm_struct *mm)
484 static inline int has_swap_token(struct mm_struct *mm)
489 static inline void disable_swap_token(struct mem_cgroup *memcg)
494 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
498 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
500 mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep)
506 #endif /* CONFIG_SWAP */
507 #endif /* __KERNEL__*/
508 #endif /* _LINUX_SWAP_H */