[net-next-2.6.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>

#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
#define MAX_SWAPFILES		(1 << MAX_SWAPFILES_SHIFT)

/*
 * 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/oom_kill.c */
extern void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order);

/* linux/mm/memory.c */
extern void swapin_readahead(swp_entry_t, unsigned long, struct vm_area_struct *);

/* linux/mm/page_alloc.c */
extern unsigned long totalram_pages;
extern unsigned long totalhigh_pages;
extern unsigned long totalreserve_pages;
extern long nr_swap_pages;
extern unsigned int nr_free_pages(void);
extern unsigned int nr_free_pages_pgdat(pg_data_t *pgdat);
extern unsigned int nr_free_buffer_pages(void);
extern unsigned int nr_free_pagecache_pages(void);

/* 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 **, gfp_t);
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);

/* possible outcome of pageout() */
typedef enum {
	/* failed to write page out, page is locked */
	PAGE_KEEP,
	/* move page to the active list, page is locked */
	PAGE_ACTIVATE,
	/* page has been sent to the disk successfully, page is unlocked */
	PAGE_SUCCESS,
	/* page is clean and locked */
	PAGE_CLEAN,
} pageout_t;

extern pageout_t pageout(struct page *page, struct address_space *mapping);

#ifdef CONFIG_NUMA
extern int zone_reclaim_mode;
extern int zone_reclaim_interval;
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

#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 int rw_swap_page_sync(int, swp_entry_t, struct page *);

/* 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 void __delete_from_swap_cache(struct page *);
extern void delete_from_swap_cache(struct page *);
extern int move_to_swap_cache(struct page *, swp_entry_t);
extern int move_from_swap_cache(struct page *, unsigned long,
		struct address_space *);
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, 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);
extern unsigned int count_swap_pages(int, int);
extern sector_t map_swap_page(struct swap_info_struct *, 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;
extern int remove_vma_swap(struct vm_area_struct *vma, struct page *page);

/* linux/mm/thrash.c */
extern struct mm_struct * swap_token_mm;
extern unsigned long swap_token_default_timeout;
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);

#define show_swap_cache_info()			/*NOTHING*/
#define free_swap_and_cache(swp)		/*NOTHING*/
#define swap_duplicate(swp)			/*NOTHING*/
#define swap_free(swp)				/*NOTHING*/
#define read_swap_cache_async(swp,vma,addr)	NULL
#define lookup_swap_cache(swp)			NULL
#define valid_swaphandles(swp, off)		0
#define can_share_swap_page(p)			(page_mapcount(p) == 1)
#define move_to_swap_cache(p, swp)		1
#define move_from_swap_cache(p, i, m)		1
#define __delete_from_swap_cache(p)		/*NOTHING*/
#define delete_from_swap_cache(p)		/*NOTHING*/
#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
	13	#define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
	14	#define SWAP_FLAG_PRIO_MASK 0x7fff
	15	#define SWAP_FLAG_PRIO_SHIFT 0
	16
	17	static inline int current_is_kswapd(void)
	18	{
	19	return current->flags & PF_KSWAPD;
	20	}
	21
	22	/*
	23	* MAX_SWAPFILES defines the maximum number of swaptypes: things which can
	24	* be swapped to. The swap type and the offset into that swap type are
	25	* encoded into pte's and into pgoff_t's in the swapcache. Using five bits
	26	* for the type means that the maximum number of swapcache pages is 27 bits
	27	* on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
	28	* the type/offset into the pte as 5/27 as well.
	29	*/
	30	#define MAX_SWAPFILES_SHIFT 5
	31	#define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
	32
	33	/*
	34	* Magic header for a swap area. The first part of the union is
	35	* what the swap magic looks like for the old (limited to 128MB)
	36	* swap area format, the second part of the union adds - in the
	37	* old reserved area - some extra information. Note that the first
	38	* kilobyte is reserved for boot loader or disk label stuff...
	39	*
	40	* Having the magic at the end of the PAGE_SIZE makes detecting swap
	41	* areas somewhat tricky on machines that support multiple page sizes.
	42	* For 2.5 we'll probably want to move the magic to just beyond the
	43	* bootbits...
	44	*/
	45	union swap_header {
	46	struct {
	47	char reserved[PAGE_SIZE - 10];
	48	char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
	49	} magic;
	50	struct {
e8f03d02 AD	51	char bootbits[1024]; /* Space for disklabel etc. */
	52	__u32 version;
	53	__u32 last_page;
	54	__u32 nr_badpages;
	55	unsigned char sws_uuid[16];
	56	unsigned char sws_volume[16];
	57	__u32 padding[117];
	58	__u32 badpages[1];
1da177e4 LT	59	} info;
	60	};
	61
	62	/* A swap entry has to fit into a "unsigned long", as
	63	* the entry is hidden in the "index" field of the
	64	* swapper address space.
	65	*/
	66	typedef struct {
	67	unsigned long val;
	68	} swp_entry_t;
	69
	70	/*
	71	* current->reclaim_state points to one of these when a task is running
	72	* memory reclaim
	73	*/
	74	struct reclaim_state {
	75	unsigned long reclaimed_slab;
	76	};
	77
	78	#ifdef __KERNEL__
	79
	80	struct address_space;
	81	struct sysinfo;
	82	struct writeback_control;
	83	struct zone;
	84
	85	/*
	86	* A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
	87	* disk blocks. A list of swap extents maps the entire swapfile. (Where the
	88	* term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
	89	* from setup, they're handled identically.
	90	*
	91	* We always assume that blocks are of size PAGE_SIZE.
	92	*/
	93	struct swap_extent {
	94	struct list_head list;
	95	pgoff_t start_page;
	96	pgoff_t nr_pages;
	97	sector_t start_block;
	98	};
	99
	100	/*
	101	* Max bad pages in the new format..
	102	*/
	103	#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
	104	#define MAX_SWAP_BADPAGES \
	105	((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
	106
	107	enum {
	108	SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
	109	SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
	110	SWP_ACTIVE = (SWP_USED \| SWP_WRITEOK),
52b7efdb HD	111	/* add others here before... */
52b7efdb HD	112	SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
1da177e4 LT	113	};
	114
	115	#define SWAP_CLUSTER_MAX 32
	116
	117	#define SWAP_MAP_MAX 0x7fff
	118	#define SWAP_MAP_BAD 0x8000
	119
	120	/*
	121	* The in-memory structure used to track swap areas.
1da177e4 LT	122	*/
	123	struct swap_info_struct {
	124	unsigned int flags;
5d337b91	125	int prio; /* swap priority */
1da177e4 LT	126	struct file *swap_file;
	127	struct block_device *bdev;
	128	struct list_head extent_list;
1da177e4 LT	129	struct swap_extent *curr_swap_extent;
	130	unsigned old_block_size;
	131	unsigned short * swap_map;
	132	unsigned int lowest_bit;
	133	unsigned int highest_bit;
	134	unsigned int cluster_next;
	135	unsigned int cluster_nr;
6eb396dc HD	136	unsigned int pages;
	137	unsigned int max;
	138	unsigned int inuse_pages;
1da177e4 LT	139	int next; /* next entry on swap list */
	140	};
	141
	142	struct swap_list_t {
	143	int head; /* head of priority-ordered swapfile list */
	144	int next; /* swapfile to be used next */
	145	};
	146
	147	/* Swap 50% full? Release swapcache more aggressively.. */
	148	#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
	149
	150	/* linux/mm/oom_kill.c */
9b0f8b04	151	extern void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order);
1da177e4 LT	152
	153	/* linux/mm/memory.c */
	154	extern void swapin_readahead(swp_entry_t, unsigned long, struct vm_area_struct *);
	155
	156	/* linux/mm/page_alloc.c */
	157	extern unsigned long totalram_pages;
	158	extern unsigned long totalhigh_pages;
cb45b0e9	159	extern unsigned long totalreserve_pages;
1da177e4 LT	160	extern long nr_swap_pages;
	161	extern unsigned int nr_free_pages(void);
	162	extern unsigned int nr_free_pages_pgdat(pg_data_t *pgdat);
	163	extern unsigned int nr_free_buffer_pages(void);
	164	extern unsigned int nr_free_pagecache_pages(void);
	165
	166	/* linux/mm/swap.c */
	167	extern void FASTCALL(lru_cache_add(struct page *));
	168	extern void FASTCALL(lru_cache_add_active(struct page *));
	169	extern void FASTCALL(activate_page(struct page *));
	170	extern void FASTCALL(mark_page_accessed(struct page *));
	171	extern void lru_add_drain(void);
053837fc	172	extern int lru_add_drain_all(void);
1da177e4 LT	173	extern int rotate_reclaimable_page(struct page *page);
	174	extern void swap_setup(void);
	175
	176	/* linux/mm/vmscan.c */
69e05944 AM	177	extern unsigned long try_to_free_pages(struct zone **, gfp_t);
69e05944 AM	178	extern unsigned long shrink_all_memory(unsigned long nr_pages);
1da177e4	179	extern int vm_swappiness;
b20a3503 CL	180	extern int remove_mapping(struct address_space mapping, struct page page);
	181
	182	/* possible outcome of pageout() */
	183	typedef enum {
	184	/* failed to write page out, page is locked */
	185	PAGE_KEEP,
	186	/* move page to the active list, page is locked */
	187	PAGE_ACTIVATE,
	188	/* page has been sent to the disk successfully, page is unlocked */
	189	PAGE_SUCCESS,
	190	/* page is clean and locked */
	191	PAGE_CLEAN,
	192	} pageout_t;
	193
	194	extern pageout_t pageout(struct page page, struct address_space mapping);
1da177e4	195
9eeff239 CL	196	#ifdef CONFIG_NUMA
9eeff239 CL	197	extern int zone_reclaim_mode;
2a11ff06	198	extern int zone_reclaim_interval;
9eeff239 CL	199	extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
	200	#else
	201	#define zone_reclaim_mode 0
	202	static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
	203	{
	204	return 0;
	205	}
	206	#endif
	207
1da177e4 LT	208	#ifdef CONFIG_MMU
	209	/* linux/mm/shmem.c */
	210	extern int shmem_unuse(swp_entry_t entry, struct page *page);
	211	#endif /* CONFIG_MMU */
	212
	213	extern void swap_unplug_io_fn(struct backing_dev_info , struct page );
	214
	215	#ifdef CONFIG_SWAP
	216	/* linux/mm/page_io.c */
	217	extern int swap_readpage(struct file , struct page );
	218	extern int swap_writepage(struct page page, struct writeback_control wbc);
	219	extern int rw_swap_page_sync(int, swp_entry_t, struct page *);
	220
	221	/* linux/mm/swap_state.c */
	222	extern struct address_space swapper_space;
	223	#define total_swapcache_pages swapper_space.nrpages
	224	extern void show_swap_cache_info(void);
1480a540	225	extern int add_to_swap(struct page *, gfp_t);
1da177e4 LT	226	extern void __delete_from_swap_cache(struct page *);
	227	extern void delete_from_swap_cache(struct page *);
	228	extern int move_to_swap_cache(struct page *, swp_entry_t);
	229	extern int move_from_swap_cache(struct page *, unsigned long,
	230	struct address_space *);
	231	extern void free_page_and_swap_cache(struct page *);
	232	extern void free_pages_and_swap_cache(struct page **, int);
	233	extern struct page * lookup_swap_cache(swp_entry_t);
	234	extern struct page * read_swap_cache_async(swp_entry_t, struct vm_area_struct *vma,
	235	unsigned long addr);
	236	/* linux/mm/swapfile.c */
	237	extern long total_swap_pages;
	238	extern unsigned int nr_swapfiles;
1da177e4 LT	239	extern void si_swapinfo(struct sysinfo *);
1da177e4 LT	240	extern swp_entry_t get_swap_page(void);
f577eb30	241	extern swp_entry_t get_swap_page_of_type(int);
1da177e4 LT	242	extern int swap_duplicate(swp_entry_t);
	243	extern int valid_swaphandles(swp_entry_t, unsigned long *);
	244	extern void swap_free(swp_entry_t);
	245	extern void free_swap_and_cache(swp_entry_t);
f577eb30 RW	246	extern int swap_type_of(dev_t);
f577eb30 RW	247	extern unsigned int count_swap_pages(int, int);
1da177e4 LT	248	extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
	249	extern struct swap_info_struct *get_swap_info_struct(unsigned);
	250	extern int can_share_swap_page(struct page *);
	251	extern int remove_exclusive_swap_page(struct page *);
	252	struct backing_dev_info;
	253
5d337b91	254	extern spinlock_t swap_lock;
a3351e52	255	extern int remove_vma_swap(struct vm_area_struct vma, struct page page);
1da177e4 LT	256
	257	/* linux/mm/thrash.c */
	258	extern struct mm_struct * swap_token_mm;
	259	extern unsigned long swap_token_default_timeout;
	260	extern void grab_swap_token(void);
	261	extern void __put_swap_token(struct mm_struct *);
	262
	263	static inline int has_swap_token(struct mm_struct *mm)
	264	{
	265	return (mm == swap_token_mm);
	266	}
	267
	268	static inline void put_swap_token(struct mm_struct *mm)
	269	{
	270	if (has_swap_token(mm))
	271	__put_swap_token(mm);
	272	}
	273
f7b7fd8f RR	274	static inline void disable_swap_token(void)
	275	{
	276	put_swap_token(swap_token_mm);
	277	}
	278
1da177e4 LT	279	#else /* CONFIG_SWAP */
	280
	281	#define total_swap_pages 0
	282	#define total_swapcache_pages 0UL
	283
	284	#define si_swapinfo(val) \
	285	do { (val)->freeswap = (val)->totalswap = 0; } while (0)
9ae5b3c7 OH	286	/* only sparc can not include linux/pagemap.h in this file
9ae5b3c7 OH	287	* so leave page_cache_release and release_pages undeclared... */
1da177e4 LT	288	#define free_page_and_swap_cache(page) \
	289	page_cache_release(page)
	290	#define free_pages_and_swap_cache(pages, nr) \
	291	release_pages((pages), (nr), 0);
	292
	293	#define show_swap_cache_info() /NOTHING/
	294	#define free_swap_and_cache(swp) /NOTHING/
	295	#define swap_duplicate(swp) /NOTHING/
	296	#define swap_free(swp) /NOTHING/
	297	#define read_swap_cache_async(swp,vma,addr) NULL
	298	#define lookup_swap_cache(swp) NULL
	299	#define valid_swaphandles(swp, off) 0
e6333fd4	300	#define can_share_swap_page(p) (page_mapcount(p) == 1)
1da177e4 LT	301	#define move_to_swap_cache(p, swp) 1
	302	#define move_from_swap_cache(p, i, m) 1
	303	#define __delete_from_swap_cache(p) /NOTHING/
	304	#define delete_from_swap_cache(p) /NOTHING/
	305	#define swap_token_default_timeout 0
	306
	307	static inline int remove_exclusive_swap_page(struct page *p)
	308	{
	309	return 0;
	310	}
	311
	312	static inline swp_entry_t get_swap_page(void)
	313	{
	314	swp_entry_t entry;
	315	entry.val = 0;
	316	return entry;
	317	}
	318
	319	/* linux/mm/thrash.c */
	320	#define put_swap_token(x) do { } while(0)
	321	#define grab_swap_token() do { } while(0)
	322	#define has_swap_token(x) 0
f7b7fd8f	323	#define disable_swap_token() do { } while(0)
1da177e4 LT	324
	325	#endif /* CONFIG_SWAP */
	326	#endif /* __KERNEL__*/
	327	#endif /* _LINUX_SWAP_H */