[deliverable/linux.git] / include / linux / swap.h

#ifndef _LINUX_SWAP_H
#define _LINUX_SWAP_H

#include <linux/spinlock.h>
#include <linux/linkage.h>
#include <linux/mmzone.h>
#include <linux/list.h>
#include <linux/sched.h>

#include <asm/atomic.h>
#include <asm/page.h>

struct notifier_block;

struct bio;

#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
#ifndef CONFIG_MIGRATION
#define MAX_SWAPFILES		(1 << MAX_SWAPFILES_SHIFT)
#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

/*
 * 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 {
		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];
	} 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),
					/* add others here before... */
	SWP_SCANNING	= (1 << 8),	/* refcount in scan_swap_map */
};

#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;
	int prio;			/* swap priority */
	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;
	unsigned int pages;
	unsigned int max;
	unsigned int inuse_pages;
	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;
extern unsigned long totalreserve_pages;
extern long nr_swap_pages;
extern unsigned int nr_free_buffer_pages(void);
extern unsigned int nr_free_pagecache_pages(void);

/* Definition of global_page_state not available yet */
#define nr_free_pages() global_page_state(NR_FREE_PAGES)


/* linux/mm/swap.c */
extern void FASTCALL(lru_cache_add(struct page *));
extern void FASTCALL(lru_cache_add_active(struct page *));
extern void FASTCALL(activate_page(struct page *));
extern void FASTCALL(mark_page_accessed(struct page *));
extern void lru_add_drain(void);
extern int lru_add_drain_all(void);
extern int rotate_reclaimable_page(struct page *page);
extern void swap_setup(void);

/* linux/mm/vmscan.c */
extern unsigned long try_to_free_pages(struct zone **zones, int order,
					gfp_t gfp_mask);
extern unsigned long shrink_all_memory(unsigned long nr_pages);
extern int vm_swappiness;
extern int remove_mapping(struct address_space *mapping, struct page *page);
extern long vm_total_pages;

#ifdef CONFIG_NUMA
extern int zone_reclaim_mode;
extern int sysctl_min_unmapped_ratio;
extern int sysctl_min_slab_ratio;
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

extern int kswapd_run(int nid);

#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);
extern void end_swap_bio_read(struct bio *bio, int err);

/* 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);
extern int add_to_swap(struct page *, gfp_t);
extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
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);
extern struct page *lookup_swap_cache(swp_entry_t);
extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
			struct vm_area_struct *vma, unsigned long addr);
extern struct page *swapin_readahead(swp_entry_t, gfp_t,
			struct vm_area_struct *vma, unsigned long addr);

/* linux/mm/swapfile.c */
extern long total_swap_pages;
extern unsigned int nr_swapfiles;
extern void si_swapinfo(struct sysinfo *);
extern swp_entry_t get_swap_page(void);
extern swp_entry_t get_swap_page_of_type(int);
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);
extern int swap_type_of(dev_t, sector_t, struct block_device **);
extern unsigned int count_swap_pages(int, int);
extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
extern sector_t swapdev_block(int, pgoff_t);
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;

extern spinlock_t swap_lock;

/* 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);
}

static inline void disable_swap_token(void)
{
	put_swap_token(swap_token_mm);
}

#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)
/* only sparc can not include linux/pagemap.h in this file
 * so leave page_cache_release and release_pages undeclared... */
#define free_page_and_swap_cache(page) \
	page_cache_release(page)
#define free_pages_and_swap_cache(pages, nr) \
	release_pages((pages), (nr), 0);

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)
{
}

static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
			struct vm_area_struct *vma, unsigned long addr)
{
	return NULL;
}

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

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

static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
							gfp_t gfp_mask)
{
	return -1;
}

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

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

#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
#define disable_swap_token() do { } while(0)

#endif /* CONFIG_SWAP */
#endif /* __KERNEL__*/
#endif /* _LINUX_SWAP_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef _LINUX_SWAP_H
	2	#define _LINUX_SWAP_H
	3
1da177e4 LT	4	#include <linux/spinlock.h>
	5	#include <linux/linkage.h>
	6	#include <linux/mmzone.h>
	7	#include <linux/list.h>
	8	#include <linux/sched.h>
542d1c88	9
1da177e4 LT	10	#include <asm/atomic.h>
	11	#include <asm/page.h>
	12
8bc719d3 MS	13	struct notifier_block;
8bc719d3 MS	14
ab954160 AM	15	struct bio;
ab954160 AM	16
1da177e4 LT	17	#define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
	18	#define SWAP_FLAG_PRIO_MASK 0x7fff
	19	#define SWAP_FLAG_PRIO_SHIFT 0
	20
	21	static inline int current_is_kswapd(void)
	22	{
	23	return current->flags & PF_KSWAPD;
	24	}
	25
	26	/*
	27	* MAX_SWAPFILES defines the maximum number of swaptypes: things which can
	28	* be swapped to. The swap type and the offset into that swap type are
	29	* encoded into pte's and into pgoff_t's in the swapcache. Using five bits
	30	* for the type means that the maximum number of swapcache pages is 27 bits
	31	* on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
	32	* the type/offset into the pte as 5/27 as well.
	33	*/
	34	#define MAX_SWAPFILES_SHIFT 5
0697212a	35	#ifndef CONFIG_MIGRATION
1da177e4	36	#define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
0697212a CL	37	#else
	38	/* Use last two entries for page migration swap entries */
	39	#define MAX_SWAPFILES ((1 << MAX_SWAPFILES_SHIFT)-2)
	40	#define SWP_MIGRATION_READ MAX_SWAPFILES
	41	#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + 1)
	42	#endif
1da177e4 LT	43
	44	/*
	45	* Magic header for a swap area. The first part of the union is
	46	* what the swap magic looks like for the old (limited to 128MB)
	47	* swap area format, the second part of the union adds - in the
	48	* old reserved area - some extra information. Note that the first
	49	* kilobyte is reserved for boot loader or disk label stuff...
	50	*
	51	* Having the magic at the end of the PAGE_SIZE makes detecting swap
	52	* areas somewhat tricky on machines that support multiple page sizes.
	53	* For 2.5 we'll probably want to move the magic to just beyond the
	54	* bootbits...
	55	*/
	56	union swap_header {
	57	struct {
	58	char reserved[PAGE_SIZE - 10];
	59	char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
	60	} magic;
	61	struct {
e8f03d02 AD	62	char bootbits[1024]; /* Space for disklabel etc. */
	63	__u32 version;
	64	__u32 last_page;
	65	__u32 nr_badpages;
	66	unsigned char sws_uuid[16];
	67	unsigned char sws_volume[16];
	68	__u32 padding[117];
	69	__u32 badpages[1];
1da177e4 LT	70	} info;
	71	};
	72
	73	/* A swap entry has to fit into a "unsigned long", as
	74	* the entry is hidden in the "index" field of the
	75	* swapper address space.
	76	*/
	77	typedef struct {
	78	unsigned long val;
	79	} swp_entry_t;
	80
	81	/*
	82	* current->reclaim_state points to one of these when a task is running
	83	* memory reclaim
	84	*/
	85	struct reclaim_state {
	86	unsigned long reclaimed_slab;
	87	};
	88
	89	#ifdef __KERNEL__
	90
	91	struct address_space;
	92	struct sysinfo;
	93	struct writeback_control;
	94	struct zone;
	95
	96	/*
	97	* A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
	98	* disk blocks. A list of swap extents maps the entire swapfile. (Where the
	99	* term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
	100	* from setup, they're handled identically.
	101	*
	102	* We always assume that blocks are of size PAGE_SIZE.
	103	*/
	104	struct swap_extent {
	105	struct list_head list;
	106	pgoff_t start_page;
	107	pgoff_t nr_pages;
	108	sector_t start_block;
	109	};
	110
	111	/*
	112	* Max bad pages in the new format..
	113	*/
	114	#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
	115	#define MAX_SWAP_BADPAGES \
	116	((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
	117
	118	enum {
	119	SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
	120	SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
	121	SWP_ACTIVE = (SWP_USED \| SWP_WRITEOK),
52b7efdb HD	122	/* add others here before... */
52b7efdb HD	123	SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
1da177e4 LT	124	};
	125
	126	#define SWAP_CLUSTER_MAX 32
	127
	128	#define SWAP_MAP_MAX 0x7fff
	129	#define SWAP_MAP_BAD 0x8000
	130
	131	/*
	132	* The in-memory structure used to track swap areas.
1da177e4 LT	133	*/
	134	struct swap_info_struct {
	135	unsigned int flags;
5d337b91	136	int prio; /* swap priority */
1da177e4 LT	137	struct file *swap_file;
	138	struct block_device *bdev;
	139	struct list_head extent_list;
1da177e4 LT	140	struct swap_extent *curr_swap_extent;
	141	unsigned old_block_size;
	142	unsigned short * swap_map;
	143	unsigned int lowest_bit;
	144	unsigned int highest_bit;
	145	unsigned int cluster_next;
	146	unsigned int cluster_nr;
6eb396dc HD	147	unsigned int pages;
	148	unsigned int max;
	149	unsigned int inuse_pages;
1da177e4 LT	150	int next; /* next entry on swap list */
	151	};
	152
	153	struct swap_list_t {
	154	int head; /* head of priority-ordered swapfile list */
	155	int next; /* swapfile to be used next */
	156	};
	157
	158	/* Swap 50% full? Release swapcache more aggressively.. */
	159	#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
	160
1da177e4 LT	161	/* linux/mm/page_alloc.c */
1da177e4 LT	162	extern unsigned long totalram_pages;
cb45b0e9	163	extern unsigned long totalreserve_pages;
1da177e4	164	extern long nr_swap_pages;
1da177e4 LT	165	extern unsigned int nr_free_buffer_pages(void);
	166	extern unsigned int nr_free_pagecache_pages(void);
	167
96177299 CL	168	/* Definition of global_page_state not available yet */
	169	#define nr_free_pages() global_page_state(NR_FREE_PAGES)
	170
	171
1da177e4 LT	172	/* linux/mm/swap.c */
	173	extern void FASTCALL(lru_cache_add(struct page *));
	174	extern void FASTCALL(lru_cache_add_active(struct page *));
	175	extern void FASTCALL(activate_page(struct page *));
	176	extern void FASTCALL(mark_page_accessed(struct page *));
	177	extern void lru_add_drain(void);
053837fc	178	extern int lru_add_drain_all(void);
1da177e4 LT	179	extern int rotate_reclaimable_page(struct page *page);
	180	extern void swap_setup(void);
	181
	182	/* linux/mm/vmscan.c */
5ad333eb AW	183	extern unsigned long try_to_free_pages(struct zone **zones, int order,
5ad333eb AW	184	gfp_t gfp_mask);
69e05944	185	extern unsigned long shrink_all_memory(unsigned long nr_pages);
1da177e4	186	extern int vm_swappiness;
b20a3503	187	extern int remove_mapping(struct address_space mapping, struct page page);
bd1e22b8	188	extern long vm_total_pages;
b20a3503	189
9eeff239 CL	190	#ifdef CONFIG_NUMA
9eeff239 CL	191	extern int zone_reclaim_mode;
9614634f	192	extern int sysctl_min_unmapped_ratio;
0ff38490	193	extern int sysctl_min_slab_ratio;
9eeff239 CL	194	extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
	195	#else
	196	#define zone_reclaim_mode 0
	197	static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
	198	{
	199	return 0;
	200	}
	201	#endif
	202
3218ae14 YG	203	extern int kswapd_run(int nid);
3218ae14 YG	204
1da177e4 LT	205	#ifdef CONFIG_MMU
	206	/* linux/mm/shmem.c */
	207	extern int shmem_unuse(swp_entry_t entry, struct page *page);
	208	#endif /* CONFIG_MMU */
	209
	210	extern void swap_unplug_io_fn(struct backing_dev_info , struct page );
	211
	212	#ifdef CONFIG_SWAP
	213	/* linux/mm/page_io.c */
	214	extern int swap_readpage(struct file , struct page );
	215	extern int swap_writepage(struct page page, struct writeback_control wbc);
6712ecf8	216	extern void end_swap_bio_read(struct bio *bio, int err);
1da177e4 LT	217
	218	/* linux/mm/swap_state.c */
	219	extern struct address_space swapper_space;
	220	#define total_swapcache_pages swapper_space.nrpages
	221	extern void show_swap_cache_info(void);
1480a540	222	extern int add_to_swap(struct page *, gfp_t);
73b1262f	223	extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
1da177e4 LT	224	extern void __delete_from_swap_cache(struct page *);
1da177e4 LT	225	extern void delete_from_swap_cache(struct page *);
1da177e4 LT	226	extern void free_page_and_swap_cache(struct page *);
1da177e4 LT	227	extern void free_pages_and_swap_cache(struct page **, int);
46017e95	228	extern struct page *lookup_swap_cache(swp_entry_t);
02098fea	229	extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
46017e95	230	struct vm_area_struct *vma, unsigned long addr);
02098fea	231	extern struct page *swapin_readahead(swp_entry_t, gfp_t,
46017e95 HD	232	struct vm_area_struct *vma, unsigned long addr);
46017e95 HD	233
1da177e4 LT	234	/* linux/mm/swapfile.c */
	235	extern long total_swap_pages;
	236	extern unsigned int nr_swapfiles;
1da177e4 LT	237	extern void si_swapinfo(struct sysinfo *);
1da177e4 LT	238	extern swp_entry_t get_swap_page(void);
f577eb30	239	extern swp_entry_t get_swap_page_of_type(int);
1da177e4 LT	240	extern int swap_duplicate(swp_entry_t);
	241	extern int valid_swaphandles(swp_entry_t, unsigned long *);
	242	extern void swap_free(swp_entry_t);
	243	extern void free_swap_and_cache(swp_entry_t);
7bf23687	244	extern int swap_type_of(dev_t, sector_t, struct block_device **);
f577eb30	245	extern unsigned int count_swap_pages(int, int);
1da177e4	246	extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
3aef83e0	247	extern sector_t swapdev_block(int, pgoff_t);
1da177e4 LT	248	extern struct swap_info_struct *get_swap_info_struct(unsigned);
	249	extern int can_share_swap_page(struct page *);
	250	extern int remove_exclusive_swap_page(struct page *);
	251	struct backing_dev_info;
	252
5d337b91	253	extern spinlock_t swap_lock;
1da177e4 LT	254
	255	/* linux/mm/thrash.c */
	256	extern struct mm_struct * swap_token_mm;
1da177e4 LT	257	extern void grab_swap_token(void);
	258	extern void __put_swap_token(struct mm_struct *);
	259
	260	static inline int has_swap_token(struct mm_struct *mm)
	261	{
	262	return (mm == swap_token_mm);
	263	}
	264
	265	static inline void put_swap_token(struct mm_struct *mm)
	266	{
	267	if (has_swap_token(mm))
	268	__put_swap_token(mm);
	269	}
	270
f7b7fd8f RR	271	static inline void disable_swap_token(void)
	272	{
	273	put_swap_token(swap_token_mm);
	274	}
	275
1da177e4 LT	276	#else /* CONFIG_SWAP */
	277
	278	#define total_swap_pages 0
	279	#define total_swapcache_pages 0UL
	280
	281	#define si_swapinfo(val) \
	282	do { (val)->freeswap = (val)->totalswap = 0; } while (0)
9ae5b3c7 OH	283	/* only sparc can not include linux/pagemap.h in this file
9ae5b3c7 OH	284	* so leave page_cache_release and release_pages undeclared... */
1da177e4 LT	285	#define free_page_and_swap_cache(page) \
	286	page_cache_release(page)
	287	#define free_pages_and_swap_cache(pages, nr) \
	288	release_pages((pages), (nr), 0);
	289
bd96b9eb CK	290	static inline void show_swap_cache_info(void)
	291	{
	292	}
	293
	294	static inline void free_swap_and_cache(swp_entry_t swp)
	295	{
	296	}
	297
	298	static inline int swap_duplicate(swp_entry_t swp)
	299	{
	300	return 0;
	301	}
	302
	303	static inline void swap_free(swp_entry_t swp)
	304	{
	305	}
	306
02098fea	307	static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
bd96b9eb CK	308	struct vm_area_struct *vma, unsigned long addr)
	309	{
	310	return NULL;
	311	}
	312
	313	static inline struct page *lookup_swap_cache(swp_entry_t swp)
	314	{
	315	return NULL;
	316	}
	317
e6333fd4	318	#define can_share_swap_page(p) (page_mapcount(p) == 1)
bd96b9eb	319
73b1262f HD	320	static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
73b1262f HD	321	gfp_t gfp_mask)
bd96b9eb	322	{
73b1262f	323	return -1;
bd96b9eb CK	324	}
	325
	326	static inline void __delete_from_swap_cache(struct page *page)
	327	{
	328	}
	329
	330	static inline void delete_from_swap_cache(struct page *page)
	331	{
	332	}
	333
1da177e4 LT	334	#define swap_token_default_timeout 0
	335
	336	static inline int remove_exclusive_swap_page(struct page *p)
	337	{
	338	return 0;
	339	}
	340
	341	static inline swp_entry_t get_swap_page(void)
	342	{
	343	swp_entry_t entry;
	344	entry.val = 0;
	345	return entry;
	346	}
	347
	348	/* linux/mm/thrash.c */
	349	#define put_swap_token(x) do { } while(0)
	350	#define grab_swap_token() do { } while(0)
	351	#define has_swap_token(x) 0
f7b7fd8f	352	#define disable_swap_token() do { } while(0)
1da177e4 LT	353
	354	#endif /* CONFIG_SWAP */
	355	#endif /* __KERNEL__*/
	356	#endif /* _LINUX_SWAP_H */