swap.h 10.1 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7
#ifndef _LINUX_SWAP_H
#define _LINUX_SWAP_H

#include <linux/spinlock.h>
#include <linux/linkage.h>
#include <linux/mmzone.h>
#include <linux/list.h>
8
#include <linux/memcontrol.h>
L
Linus Torvalds 已提交
9
#include <linux/sched.h>
A
Andrew Morton 已提交
10

L
Linus Torvalds 已提交
11 12 13
#include <asm/atomic.h>
#include <asm/page.h>

14 15
struct notifier_block;

A
Andrew Morton 已提交
16 17
struct bio;

L
Linus Torvalds 已提交
18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
#define SWAP_FLAG_PREFER	0x8000	/* set if swap priority specified */
#define SWAP_FLAG_PRIO_MASK	0x7fff
#define SWAP_FLAG_PRIO_SHIFT	0

static inline int current_is_kswapd(void)
{
	return current->flags & PF_KSWAPD;
}

/*
 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
 * be swapped to.  The swap type and the offset into that swap type are
 * encoded into pte's and into pgoff_t's in the swapcache.  Using five bits
 * for the type means that the maximum number of swapcache pages is 27 bits
 * on 32-bit-pgoff_t architectures.  And that assumes that the architecture packs
 * the type/offset into the pte as 5/27 as well.
 */
#define MAX_SWAPFILES_SHIFT	5
36
#ifndef CONFIG_MIGRATION
L
Linus Torvalds 已提交
37
#define MAX_SWAPFILES		(1 << MAX_SWAPFILES_SHIFT)
38 39 40 41 42 43
#else
/* Use last two entries for page migration swap entries */
#define MAX_SWAPFILES		((1 << MAX_SWAPFILES_SHIFT)-2)
#define SWP_MIGRATION_READ	MAX_SWAPFILES
#define SWP_MIGRATION_WRITE	(MAX_SWAPFILES + 1)
#endif
L
Linus Torvalds 已提交
44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62

/*
 * Magic header for a swap area. The first part of the union is
 * what the swap magic looks like for the old (limited to 128MB)
 * swap area format, the second part of the union adds - in the
 * old reserved area - some extra information. Note that the first
 * kilobyte is reserved for boot loader or disk label stuff...
 *
 * Having the magic at the end of the PAGE_SIZE makes detecting swap
 * areas somewhat tricky on machines that support multiple page sizes.
 * For 2.5 we'll probably want to move the magic to just beyond the
 * bootbits...
 */
union swap_header {
	struct {
		char reserved[PAGE_SIZE - 10];
		char magic[10];			/* SWAP-SPACE or SWAPSPACE2 */
	} magic;
	struct {
63 64 65 66 67 68 69 70
		char		bootbits[1024];	/* Space for disklabel etc. */
		__u32		version;
		__u32		last_page;
		__u32		nr_badpages;
		unsigned char	sws_uuid[16];
		unsigned char	sws_volume[16];
		__u32		padding[117];
		__u32		badpages[1];
L
Linus Torvalds 已提交
71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122
	} info;
};

 /* A swap entry has to fit into a "unsigned long", as
  * the entry is hidden in the "index" field of the
  * swapper address space.
  */
typedef struct {
	unsigned long val;
} swp_entry_t;

/*
 * current->reclaim_state points to one of these when a task is running
 * memory reclaim
 */
struct reclaim_state {
	unsigned long reclaimed_slab;
};

#ifdef __KERNEL__

struct address_space;
struct sysinfo;
struct writeback_control;
struct zone;

/*
 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
 * disk blocks.  A list of swap extents maps the entire swapfile.  (Where the
 * term `swapfile' refers to either a blockdevice or an IS_REG file.  Apart
 * from setup, they're handled identically.
 *
 * We always assume that blocks are of size PAGE_SIZE.
 */
struct swap_extent {
	struct list_head list;
	pgoff_t start_page;
	pgoff_t nr_pages;
	sector_t start_block;
};

/*
 * Max bad pages in the new format..
 */
#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
#define MAX_SWAP_BADPAGES \
	((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))

enum {
	SWP_USED	= (1 << 0),	/* is slot in swap_info[] used? */
	SWP_WRITEOK	= (1 << 1),	/* ok to write to this swap?	*/
	SWP_ACTIVE	= (SWP_USED | SWP_WRITEOK),
123 124
					/* add others here before... */
	SWP_SCANNING	= (1 << 8),	/* refcount in scan_swap_map */
L
Linus Torvalds 已提交
125 126 127 128 129 130 131 132 133 134 135 136
};

#define SWAP_CLUSTER_MAX 32

#define SWAP_MAP_MAX	0x7fff
#define SWAP_MAP_BAD	0x8000

/*
 * The in-memory structure used to track swap areas.
 */
struct swap_info_struct {
	unsigned int flags;
137
	int prio;			/* swap priority */
L
Linus Torvalds 已提交
138 139 140 141 142 143 144 145 146 147
	struct file *swap_file;
	struct block_device *bdev;
	struct list_head extent_list;
	struct swap_extent *curr_swap_extent;
	unsigned old_block_size;
	unsigned short * swap_map;
	unsigned int lowest_bit;
	unsigned int highest_bit;
	unsigned int cluster_next;
	unsigned int cluster_nr;
148 149 150
	unsigned int pages;
	unsigned int max;
	unsigned int inuse_pages;
L
Linus Torvalds 已提交
151 152 153 154 155 156 157 158 159 160 161 162 163
	int next;			/* next entry on swap list */
};

struct swap_list_t {
	int head;	/* head of priority-ordered swapfile list */
	int next;	/* swapfile to be used next */
};

/* Swap 50% full? Release swapcache more aggressively.. */
#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)

/* linux/mm/page_alloc.c */
extern unsigned long totalram_pages;
164
extern unsigned long totalreserve_pages;
L
Linus Torvalds 已提交
165 166 167 168
extern long nr_swap_pages;
extern unsigned int nr_free_buffer_pages(void);
extern unsigned int nr_free_pagecache_pages(void);

C
Christoph Lameter 已提交
169 170 171 172
/* Definition of global_page_state not available yet */
#define nr_free_pages() global_page_state(NR_FREE_PAGES)


L
Linus Torvalds 已提交
173
/* linux/mm/swap.c */
174 175
extern void __lru_cache_add(struct page *, enum lru_list lru);
extern void lru_cache_add_lru(struct page *, enum lru_list lru);
176 177
extern void activate_page(struct page *);
extern void mark_page_accessed(struct page *);
L
Linus Torvalds 已提交
178
extern void lru_add_drain(void);
179
extern int lru_add_drain_all(void);
180
extern void rotate_reclaimable_page(struct page *page);
L
Linus Torvalds 已提交
181 182
extern void swap_setup(void);

183 184 185 186 187 188 189 190 191 192 193 194 195 196
/**
 * lru_cache_add: add a page to the page lists
 * @page: the page to add
 */
static inline void lru_cache_add(struct page *page)
{
	__lru_cache_add(page, LRU_INACTIVE);
}

static inline void lru_cache_add_active(struct page *page)
{
	__lru_cache_add(page, LRU_ACTIVE);
}

L
Linus Torvalds 已提交
197
/* linux/mm/vmscan.c */
198
extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
A
Andy Whitcroft 已提交
199
					gfp_t gfp_mask);
200 201
extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
							gfp_t gfp_mask);
202
extern int __isolate_lru_page(struct page *page, int mode);
203
extern unsigned long shrink_all_memory(unsigned long nr_pages);
L
Linus Torvalds 已提交
204
extern int vm_swappiness;
C
Christoph Lameter 已提交
205
extern int remove_mapping(struct address_space *mapping, struct page *page);
206
extern long vm_total_pages;
C
Christoph Lameter 已提交
207

208 209
#ifdef CONFIG_NUMA
extern int zone_reclaim_mode;
210
extern int sysctl_min_unmapped_ratio;
211
extern int sysctl_min_slab_ratio;
212 213 214 215 216 217 218 219 220
extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
#else
#define zone_reclaim_mode 0
static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
{
	return 0;
}
#endif

221 222
extern int kswapd_run(int nid);

L
Linus Torvalds 已提交
223 224 225 226 227 228 229 230 231 232 233
#ifdef CONFIG_MMU
/* linux/mm/shmem.c */
extern int shmem_unuse(swp_entry_t entry, struct page *page);
#endif /* CONFIG_MMU */

extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);

#ifdef CONFIG_SWAP
/* linux/mm/page_io.c */
extern int swap_readpage(struct file *, struct page *);
extern int swap_writepage(struct page *page, struct writeback_control *wbc);
234
extern void end_swap_bio_read(struct bio *bio, int err);
L
Linus Torvalds 已提交
235 236 237 238 239

/* linux/mm/swap_state.c */
extern struct address_space swapper_space;
#define total_swapcache_pages  swapper_space.nrpages
extern void show_swap_cache_info(void);
240
extern int add_to_swap(struct page *, gfp_t);
241
extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
L
Linus Torvalds 已提交
242 243 244 245
extern void __delete_from_swap_cache(struct page *);
extern void delete_from_swap_cache(struct page *);
extern void free_page_and_swap_cache(struct page *);
extern void free_pages_and_swap_cache(struct page **, int);
246
extern struct page *lookup_swap_cache(swp_entry_t);
247
extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
248
			struct vm_area_struct *vma, unsigned long addr);
249
extern struct page *swapin_readahead(swp_entry_t, gfp_t,
250 251
			struct vm_area_struct *vma, unsigned long addr);

L
Linus Torvalds 已提交
252 253 254 255
/* linux/mm/swapfile.c */
extern long total_swap_pages;
extern void si_swapinfo(struct sysinfo *);
extern swp_entry_t get_swap_page(void);
256
extern swp_entry_t get_swap_page_of_type(int);
L
Linus Torvalds 已提交
257 258 259 260
extern int swap_duplicate(swp_entry_t);
extern int valid_swaphandles(swp_entry_t, unsigned long *);
extern void swap_free(swp_entry_t);
extern void free_swap_and_cache(swp_entry_t);
261
extern int swap_type_of(dev_t, sector_t, struct block_device **);
262
extern unsigned int count_swap_pages(int, int);
L
Linus Torvalds 已提交
263
extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
264
extern sector_t swapdev_block(int, pgoff_t);
L
Linus Torvalds 已提交
265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285
extern struct swap_info_struct *get_swap_info_struct(unsigned);
extern int can_share_swap_page(struct page *);
extern int remove_exclusive_swap_page(struct page *);
struct backing_dev_info;

/* linux/mm/thrash.c */
extern struct mm_struct * swap_token_mm;
extern void grab_swap_token(void);
extern void __put_swap_token(struct mm_struct *);

static inline int has_swap_token(struct mm_struct *mm)
{
	return (mm == swap_token_mm);
}

static inline void put_swap_token(struct mm_struct *mm)
{
	if (has_swap_token(mm))
		__put_swap_token(mm);
}

286 287 288 289 290
static inline void disable_swap_token(void)
{
	put_swap_token(swap_token_mm);
}

L
Linus Torvalds 已提交
291 292 293 294 295 296 297
#else /* CONFIG_SWAP */

#define total_swap_pages			0
#define total_swapcache_pages			0UL

#define si_swapinfo(val) \
	do { (val)->freeswap = (val)->totalswap = 0; } while (0)
298 299
/* only sparc can not include linux/pagemap.h in this file
 * so leave page_cache_release and release_pages undeclared... */
L
Linus Torvalds 已提交
300 301 302 303 304
#define free_page_and_swap_cache(page) \
	page_cache_release(page)
#define free_pages_and_swap_cache(pages, nr) \
	release_pages((pages), (nr), 0);

305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321
static inline void show_swap_cache_info(void)
{
}

static inline void free_swap_and_cache(swp_entry_t swp)
{
}

static inline int swap_duplicate(swp_entry_t swp)
{
	return 0;
}

static inline void swap_free(swp_entry_t swp)
{
}

322
static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
323 324 325 326 327 328 329 330 331 332
			struct vm_area_struct *vma, unsigned long addr)
{
	return NULL;
}

static inline struct page *lookup_swap_cache(swp_entry_t swp)
{
	return NULL;
}

333
#define can_share_swap_page(p)			(page_mapcount(p) == 1)
334

335 336
static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
							gfp_t gfp_mask)
337
{
338
	return -1;
339 340 341 342 343 344 345 346 347 348
}

static inline void __delete_from_swap_cache(struct page *page)
{
}

static inline void delete_from_swap_cache(struct page *page)
{
}

L
Linus Torvalds 已提交
349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366
#define swap_token_default_timeout		0

static inline int remove_exclusive_swap_page(struct page *p)
{
	return 0;
}

static inline swp_entry_t get_swap_page(void)
{
	swp_entry_t entry;
	entry.val = 0;
	return entry;
}

/* linux/mm/thrash.c */
#define put_swap_token(x) do { } while(0)
#define grab_swap_token()  do { } while(0)
#define has_swap_token(x) 0
367
#define disable_swap_token() do { } while(0)
L
Linus Torvalds 已提交
368 369 370 371

#endif /* CONFIG_SWAP */
#endif /* __KERNEL__*/
#endif /* _LINUX_SWAP_H */