~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/include/linux/swap.h

Version: ~ [ linux-5.3-rc5 ] ~ [ linux-5.2.9 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.67 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.139 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.189 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.189 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.72 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 #ifndef _LINUX_SWAP_H
  2 #define _LINUX_SWAP_H
  3 
  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>
 11 #include <linux/fs.h>
 12 #include <linux/atomic.h>
 13 #include <linux/page-flags.h>
 14 #include <asm/page.h>
 15 
 16 struct notifier_block;
 17 
 18 struct bio;
 19 
 20 #define SWAP_FLAG_PREFER        0x8000  /* set if swap priority specified */
 21 #define SWAP_FLAG_PRIO_MASK     0x7fff
 22 #define SWAP_FLAG_PRIO_SHIFT    0
 23 #define SWAP_FLAG_DISCARD       0x10000 /* enable discard for swap */
 24 #define SWAP_FLAG_DISCARD_ONCE  0x20000 /* discard swap area at swapon-time */
 25 #define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */
 26 
 27 #define SWAP_FLAGS_VALID        (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \
 28                                  SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \
 29                                  SWAP_FLAG_DISCARD_PAGES)
 30 
 31 static inline int current_is_kswapd(void)
 32 {
 33         return current->flags & PF_KSWAPD;
 34 }
 35 
 36 /*
 37  * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
 38  * be swapped to.  The swap type and the offset into that swap type are
 39  * encoded into pte's and into pgoff_t's in the swapcache.  Using five bits
 40  * for the type means that the maximum number of swapcache pages is 27 bits
 41  * on 32-bit-pgoff_t architectures.  And that assumes that the architecture packs
 42  * the type/offset into the pte as 5/27 as well.
 43  */
 44 #define MAX_SWAPFILES_SHIFT     5
 45 
 46 /*
 47  * Use some of the swap files numbers for other purposes. This
 48  * is a convenient way to hook into the VM to trigger special
 49  * actions on faults.
 50  */
 51 
 52 /*
 53  * NUMA node memory migration support
 54  */
 55 #ifdef CONFIG_MIGRATION
 56 #define SWP_MIGRATION_NUM 2
 57 #define SWP_MIGRATION_READ      (MAX_SWAPFILES + SWP_HWPOISON_NUM)
 58 #define SWP_MIGRATION_WRITE     (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
 59 #else
 60 #define SWP_MIGRATION_NUM 0
 61 #endif
 62 
 63 /*
 64  * Handling of hardware poisoned pages with memory corruption.
 65  */
 66 #ifdef CONFIG_MEMORY_FAILURE
 67 #define SWP_HWPOISON_NUM 1
 68 #define SWP_HWPOISON            MAX_SWAPFILES
 69 #else
 70 #define SWP_HWPOISON_NUM 0
 71 #endif
 72 
 73 #define MAX_SWAPFILES \
 74         ((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)
 75 
 76 /*
 77  * Magic header for a swap area. The first part of the union is
 78  * what the swap magic looks like for the old (limited to 128MB)
 79  * swap area format, the second part of the union adds - in the
 80  * old reserved area - some extra information. Note that the first
 81  * kilobyte is reserved for boot loader or disk label stuff...
 82  *
 83  * Having the magic at the end of the PAGE_SIZE makes detecting swap
 84  * areas somewhat tricky on machines that support multiple page sizes.
 85  * For 2.5 we'll probably want to move the magic to just beyond the
 86  * bootbits...
 87  */
 88 union swap_header {
 89         struct {
 90                 char reserved[PAGE_SIZE - 10];
 91                 char magic[10];                 /* SWAP-SPACE or SWAPSPACE2 */
 92         } magic;
 93         struct {
 94                 char            bootbits[1024]; /* Space for disklabel etc. */
 95                 __u32           version;
 96                 __u32           last_page;
 97                 __u32           nr_badpages;
 98                 unsigned char   sws_uuid[16];
 99                 unsigned char   sws_volume[16];
100                 __u32           padding[117];
101                 __u32           badpages[1];
102         } info;
103 };
104 
105  /* A swap entry has to fit into a "unsigned long", as
106   * the entry is hidden in the "index" field of the
107   * swapper address space.
108   */
109 typedef struct {
110         unsigned long val;
111 } swp_entry_t;
112 
113 /*
114  * current->reclaim_state points to one of these when a task is running
115  * memory reclaim
116  */
117 struct reclaim_state {
118         unsigned long reclaimed_slab;
119 };
120 
121 #ifdef __KERNEL__
122 
123 struct address_space;
124 struct sysinfo;
125 struct writeback_control;
126 struct zone;
127 
128 /*
129  * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
130  * disk blocks.  A list of swap extents maps the entire swapfile.  (Where the
131  * term `swapfile' refers to either a blockdevice or an IS_REG file.  Apart
132  * from setup, they're handled identically.
133  *
134  * We always assume that blocks are of size PAGE_SIZE.
135  */
136 struct swap_extent {
137         struct list_head list;
138         pgoff_t start_page;
139         pgoff_t nr_pages;
140         sector_t start_block;
141 };
142 
143 /*
144  * Max bad pages in the new format..
145  */
146 #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
147 #define MAX_SWAP_BADPAGES \
148         ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
149 
150 enum {
151         SWP_USED        = (1 << 0),     /* is slot in swap_info[] used? */
152         SWP_WRITEOK     = (1 << 1),     /* ok to write to this swap?    */
153         SWP_DISCARDABLE = (1 << 2),     /* blkdev support discard */
154         SWP_DISCARDING  = (1 << 3),     /* now discarding a free cluster */
155         SWP_SOLIDSTATE  = (1 << 4),     /* blkdev seeks are cheap */
156         SWP_CONTINUED   = (1 << 5),     /* swap_map has count continuation */
157         SWP_BLKDEV      = (1 << 6),     /* its a block device */
158         SWP_FILE        = (1 << 7),     /* set after swap_activate success */
159         SWP_AREA_DISCARD = (1 << 8),    /* single-time swap area discards */
160         SWP_PAGE_DISCARD = (1 << 9),    /* freed swap page-cluster discards */
161                                         /* add others here before... */
162         SWP_SCANNING    = (1 << 10),    /* refcount in scan_swap_map */
163 };
164 
165 #define SWAP_CLUSTER_MAX 32UL
166 #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
167 
168 /*
169  * Ratio between the present memory in the zone and the "gap" that
170  * we're allowing kswapd to shrink in addition to the per-zone high
171  * wmark, even for zones that already have the high wmark satisfied,
172  * in order to provide better per-zone lru behavior. We are ok to
173  * spend not more than 1% of the memory for this zone balancing "gap".
174  */
175 #define KSWAPD_ZONE_BALANCE_GAP_RATIO 100
176 
177 #define SWAP_MAP_MAX    0x3e    /* Max duplication count, in first swap_map */
178 #define SWAP_MAP_BAD    0x3f    /* Note pageblock is bad, in first swap_map */
179 #define SWAP_HAS_CACHE  0x40    /* Flag page is cached, in first swap_map */
180 #define SWAP_CONT_MAX   0x7f    /* Max count, in each swap_map continuation */
181 #define COUNT_CONTINUED 0x80    /* See swap_map continuation for full count */
182 #define SWAP_MAP_SHMEM  0xbf    /* Owned by shmem/tmpfs, in first swap_map */
183 
184 /*
185  * The in-memory structure used to track swap areas.
186  */
187 struct swap_info_struct {
188         unsigned long   flags;          /* SWP_USED etc: see above */
189         signed short    prio;           /* swap priority of this type */
190         signed char     type;           /* strange name for an index */
191         signed char     next;           /* next type on the swap list */
192         unsigned int    max;            /* extent of the swap_map */
193         unsigned char *swap_map;        /* vmalloc'ed array of usage counts */
194         unsigned int lowest_bit;        /* index of first free in swap_map */
195         unsigned int highest_bit;       /* index of last free in swap_map */
196         unsigned int pages;             /* total of usable pages of swap */
197         unsigned int inuse_pages;       /* number of those currently in use */
198         unsigned int cluster_next;      /* likely index for next allocation */
199         unsigned int cluster_nr;        /* countdown to next cluster search */
200         unsigned int lowest_alloc;      /* while preparing discard cluster */
201         unsigned int highest_alloc;     /* while preparing discard cluster */
202         struct swap_extent *curr_swap_extent;
203         struct swap_extent first_swap_extent;
204         struct block_device *bdev;      /* swap device or bdev of swap file */
205         struct file *swap_file;         /* seldom referenced */
206         unsigned int old_block_size;    /* seldom referenced */
207 #ifdef CONFIG_FRONTSWAP
208         unsigned long *frontswap_map;   /* frontswap in-use, one bit per page */
209         atomic_t frontswap_pages;       /* frontswap pages in-use counter */
210 #endif
211         spinlock_t lock;                /*
212                                          * protect map scan related fields like
213                                          * swap_map, lowest_bit, highest_bit,
214                                          * inuse_pages, cluster_next,
215                                          * cluster_nr, lowest_alloc and
216                                          * highest_alloc. other fields are only
217                                          * changed at swapon/swapoff, so are
218                                          * protected by swap_lock. changing
219                                          * flags need hold this lock and
220                                          * swap_lock. If both locks need hold,
221                                          * hold swap_lock first.
222                                          */
223 };
224 
225 struct swap_list_t {
226         int head;       /* head of priority-ordered swapfile list */
227         int next;       /* swapfile to be used next */
228 };
229 
230 /* linux/mm/page_alloc.c */
231 extern unsigned long totalram_pages;
232 extern unsigned long totalreserve_pages;
233 extern unsigned long dirty_balance_reserve;
234 extern unsigned long nr_free_buffer_pages(void);
235 extern unsigned long nr_free_pagecache_pages(void);
236 
237 /* Definition of global_page_state not available yet */
238 #define nr_free_pages() global_page_state(NR_FREE_PAGES)
239 
240 
241 /* linux/mm/swap.c */
242 extern void __lru_cache_add(struct page *);
243 extern void lru_cache_add(struct page *);
244 extern void lru_add_page_tail(struct page *page, struct page *page_tail,
245                          struct lruvec *lruvec, struct list_head *head);
246 extern void activate_page(struct page *);
247 extern void mark_page_accessed(struct page *);
248 extern void lru_add_drain(void);
249 extern void lru_add_drain_cpu(int cpu);
250 extern int lru_add_drain_all(void);
251 extern void rotate_reclaimable_page(struct page *page);
252 extern void deactivate_page(struct page *page);
253 extern void swap_setup(void);
254 
255 extern void add_page_to_unevictable_list(struct page *page);
256 
257 /**
258  * lru_cache_add: add a page to the page lists
259  * @page: the page to add
260  */
261 static inline void lru_cache_add_anon(struct page *page)
262 {
263         ClearPageActive(page);
264         __lru_cache_add(page);
265 }
266 
267 static inline void lru_cache_add_file(struct page *page)
268 {
269         ClearPageActive(page);
270         __lru_cache_add(page);
271 }
272 
273 /* linux/mm/vmscan.c */
274 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
275                                         gfp_t gfp_mask, nodemask_t *mask);
276 extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
277 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
278                                                   gfp_t gfp_mask, bool noswap);
279 extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
280                                                 gfp_t gfp_mask, bool noswap,
281                                                 struct zone *zone,
282                                                 unsigned long *nr_scanned);
283 extern unsigned long shrink_all_memory(unsigned long nr_pages);
284 extern int vm_swappiness;
285 extern int remove_mapping(struct address_space *mapping, struct page *page);
286 extern unsigned long vm_total_pages;
287 
288 #ifdef CONFIG_NUMA
289 extern int zone_reclaim_mode;
290 extern int sysctl_min_unmapped_ratio;
291 extern int sysctl_min_slab_ratio;
292 extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
293 #else
294 #define zone_reclaim_mode 0
295 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
296 {
297         return 0;
298 }
299 #endif
300 
301 extern int page_evictable(struct page *page);
302 extern void check_move_unevictable_pages(struct page **, int nr_pages);
303 
304 extern unsigned long scan_unevictable_pages;
305 extern int scan_unevictable_handler(struct ctl_table *, int,
306                                         void __user *, size_t *, loff_t *);
307 #ifdef CONFIG_NUMA
308 extern int scan_unevictable_register_node(struct node *node);
309 extern void scan_unevictable_unregister_node(struct node *node);
310 #else
311 static inline int scan_unevictable_register_node(struct node *node)
312 {
313         return 0;
314 }
315 static inline void scan_unevictable_unregister_node(struct node *node)
316 {
317 }
318 #endif
319 
320 extern int kswapd_run(int nid);
321 extern void kswapd_stop(int nid);
322 #ifdef CONFIG_MEMCG
323 extern int mem_cgroup_swappiness(struct mem_cgroup *mem);
324 #else
325 static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
326 {
327         return vm_swappiness;
328 }
329 #endif
330 #ifdef CONFIG_MEMCG_SWAP
331 extern void mem_cgroup_uncharge_swap(swp_entry_t ent);
332 #else
333 static inline void mem_cgroup_uncharge_swap(swp_entry_t ent)
334 {
335 }
336 #endif
337 #ifdef CONFIG_SWAP
338 /* linux/mm/page_io.c */
339 extern int swap_readpage(struct page *);
340 extern int swap_writepage(struct page *page, struct writeback_control *wbc);
341 extern void end_swap_bio_write(struct bio *bio, int err);
342 extern int __swap_writepage(struct page *page, struct writeback_control *wbc,
343         void (*end_write_func)(struct bio *, int));
344 extern int swap_set_page_dirty(struct page *page);
345 extern void end_swap_bio_read(struct bio *bio, int err);
346 
347 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
348                 unsigned long nr_pages, sector_t start_block);
349 int generic_swapfile_activate(struct swap_info_struct *, struct file *,
350                 sector_t *);
351 
352 /* linux/mm/swap_state.c */
353 extern struct address_space swapper_spaces[];
354 #define swap_address_space(entry) (&swapper_spaces[swp_type(entry)])
355 extern unsigned long total_swapcache_pages(void);
356 extern void show_swap_cache_info(void);
357 extern int add_to_swap(struct page *, struct list_head *list);
358 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
359 extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
360 extern void __delete_from_swap_cache(struct page *);
361 extern void delete_from_swap_cache(struct page *);
362 extern void free_page_and_swap_cache(struct page *);
363 extern void free_pages_and_swap_cache(struct page **, int);
364 extern struct page *lookup_swap_cache(swp_entry_t);
365 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
366                         struct vm_area_struct *vma, unsigned long addr);
367 extern struct page *swapin_readahead(swp_entry_t, gfp_t,
368                         struct vm_area_struct *vma, unsigned long addr);
369 
370 /* linux/mm/swapfile.c */
371 extern atomic_long_t nr_swap_pages;
372 extern long total_swap_pages;
373 
374 /* Swap 50% full? Release swapcache more aggressively.. */
375 static inline bool vm_swap_full(void)
376 {
377         return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
378 }
379 
380 static inline long get_nr_swap_pages(void)
381 {
382         return atomic_long_read(&nr_swap_pages);
383 }
384 
385 extern void si_swapinfo(struct sysinfo *);
386 extern swp_entry_t get_swap_page(void);
387 extern swp_entry_t get_swap_page_of_type(int);
388 extern int add_swap_count_continuation(swp_entry_t, gfp_t);
389 extern void swap_shmem_alloc(swp_entry_t);
390 extern int swap_duplicate(swp_entry_t);
391 extern int swapcache_prepare(swp_entry_t);
392 extern void swap_free(swp_entry_t);
393 extern void swapcache_free(swp_entry_t, struct page *page);
394 extern int free_swap_and_cache(swp_entry_t);
395 extern int swap_type_of(dev_t, sector_t, struct block_device **);
396 extern unsigned int count_swap_pages(int, int);
397 extern sector_t map_swap_page(struct page *, struct block_device **);
398 extern sector_t swapdev_block(int, pgoff_t);
399 extern int page_swapcount(struct page *);
400 extern struct swap_info_struct *page_swap_info(struct page *);
401 extern int reuse_swap_page(struct page *);
402 extern int try_to_free_swap(struct page *);
403 struct backing_dev_info;
404 
405 #ifdef CONFIG_MEMCG
406 extern void
407 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout);
408 #else
409 static inline void
410 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
411 {
412 }
413 #endif
414 
415 #else /* CONFIG_SWAP */
416 
417 #define get_nr_swap_pages()                     0L
418 #define total_swap_pages                        0L
419 #define total_swapcache_pages()                 0UL
420 #define vm_swap_full()                          0
421 
422 #define si_swapinfo(val) \
423         do { (val)->freeswap = (val)->totalswap = 0; } while (0)
424 /* only sparc can not include linux/pagemap.h in this file
425  * so leave page_cache_release and release_pages undeclared... */
426 #define free_page_and_swap_cache(page) \
427         page_cache_release(page)
428 #define free_pages_and_swap_cache(pages, nr) \
429         release_pages((pages), (nr), 0);
430 
431 static inline void show_swap_cache_info(void)
432 {
433 }
434 
435 #define free_swap_and_cache(swp)        is_migration_entry(swp)
436 #define swapcache_prepare(swp)          is_migration_entry(swp)
437 
438 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
439 {
440         return 0;
441 }
442 
443 static inline void swap_shmem_alloc(swp_entry_t swp)
444 {
445 }
446 
447 static inline int swap_duplicate(swp_entry_t swp)
448 {
449         return 0;
450 }
451 
452 static inline void swap_free(swp_entry_t swp)
453 {
454 }
455 
456 static inline void swapcache_free(swp_entry_t swp, struct page *page)
457 {
458 }
459 
460 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
461                         struct vm_area_struct *vma, unsigned long addr)
462 {
463         return NULL;
464 }
465 
466 static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
467 {
468         return 0;
469 }
470 
471 static inline struct page *lookup_swap_cache(swp_entry_t swp)
472 {
473         return NULL;
474 }
475 
476 static inline int add_to_swap(struct page *page, struct list_head *list)
477 {
478         return 0;
479 }
480 
481 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
482                                                         gfp_t gfp_mask)
483 {
484         return -1;
485 }
486 
487 static inline void __delete_from_swap_cache(struct page *page)
488 {
489 }
490 
491 static inline void delete_from_swap_cache(struct page *page)
492 {
493 }
494 
495 static inline int page_swapcount(struct page *page)
496 {
497         return 0;
498 }
499 
500 #define reuse_swap_page(page)   (page_mapcount(page) == 1)
501 
502 static inline int try_to_free_swap(struct page *page)
503 {
504         return 0;
505 }
506 
507 static inline swp_entry_t get_swap_page(void)
508 {
509         swp_entry_t entry;
510         entry.val = 0;
511         return entry;
512 }
513 
514 static inline void
515 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
516 {
517 }
518 
519 #endif /* CONFIG_SWAP */
520 #endif /* __KERNEL__*/
521 #endif /* _LINUX_SWAP_H */
522 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp