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

#ifndef _LINUX_SWAP_H
#define _LINUX_SWAP_H

#include <linux/config.h>
#include <linux/spinlock.h>
#include <linux/linkage.h>
#include <linux/mmzone.h>
#include <linux/list.h>
#include <linux/sched.h>
#include <linux/pagemap.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. */
		unsigned int version;
		unsigned int last_page;
		unsigned int nr_badpages;
		unsigned int padding[125];
		unsigned int 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),
};

#define SWAP_CLUSTER_MAX 32

#define SWAP_MAP_MAX	0x7fff
#define SWAP_MAP_BAD	0x8000

/*
 * The in-memory structure used to track swap areas.
 * extent_list.prev points at the lowest-index extent.  That list is
 * sorted.
 */
struct swap_info_struct {
	unsigned int flags;
	spinlock_t sdev_lock;
	struct file *swap_file;
	struct block_device *bdev;
	struct list_head extent_list;
	int nr_extents;
	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;
	int prio;			/* swap priority */
	int pages;
	unsigned long max;
	unsigned long 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(unsigned int __nocast 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 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 rotate_reclaimable_page(struct page *page);
extern void swap_setup(void);

/* linux/mm/vmscan.c */
extern int try_to_free_pages(struct zone **, unsigned int);
extern int zone_reclaim(struct zone *, unsigned int, unsigned int);
extern int shrink_all_memory(int);
extern int vm_swappiness;

#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 *);
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 struct swap_info_struct swap_info[];
extern void si_swapinfo(struct sysinfo *);
extern swp_entry_t get_swap_page(void);
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 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 struct swap_list_t swap_list;
extern spinlock_t swaplock;

#define swap_list_lock()	spin_lock(&swaplock)
#define swap_list_unlock()	spin_unlock(&swaplock)
#define swap_device_lock(p)	spin_lock(&p->sdev_lock)
#define swap_device_unlock(p)	spin_unlock(&p->sdev_lock)

/* 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);
}

#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)
#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)			0
#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

#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
	4	#include <linux/config.h>
	5	#include <linux/spinlock.h>
	6	#include <linux/linkage.h>
	7	#include <linux/mmzone.h>
	8	#include <linux/list.h>
	9	#include <linux/sched.h>
542d1c88 AM	10	#include <linux/pagemap.h>
542d1c88 AM	11
1da177e4 LT	12	#include <asm/atomic.h>
	13	#include <asm/page.h>
	14
	15	#define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
	16	#define SWAP_FLAG_PRIO_MASK 0x7fff
	17	#define SWAP_FLAG_PRIO_SHIFT 0
	18
	19	static inline int current_is_kswapd(void)
	20	{
	21	return current->flags & PF_KSWAPD;
	22	}
	23
	24	/*
	25	* MAX_SWAPFILES defines the maximum number of swaptypes: things which can
	26	* be swapped to. The swap type and the offset into that swap type are
	27	* encoded into pte's and into pgoff_t's in the swapcache. Using five bits
	28	* for the type means that the maximum number of swapcache pages is 27 bits
	29	* on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
	30	* the type/offset into the pte as 5/27 as well.
	31	*/
	32	#define MAX_SWAPFILES_SHIFT 5
	33	#define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
	34
	35	/*
	36	* Magic header for a swap area. The first part of the union is
	37	* what the swap magic looks like for the old (limited to 128MB)
	38	* swap area format, the second part of the union adds - in the
	39	* old reserved area - some extra information. Note that the first
	40	* kilobyte is reserved for boot loader or disk label stuff...
	41	*
	42	* Having the magic at the end of the PAGE_SIZE makes detecting swap
	43	* areas somewhat tricky on machines that support multiple page sizes.
	44	* For 2.5 we'll probably want to move the magic to just beyond the
	45	* bootbits...
	46	*/
	47	union swap_header {
	48	struct {
	49	char reserved[PAGE_SIZE - 10];
	50	char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
	51	} magic;
	52	struct {
	53	char bootbits[1024]; /* Space for disklabel etc. */
	54	unsigned int version;
	55	unsigned int last_page;
	56	unsigned int nr_badpages;
	57	unsigned int padding[125];
	58	unsigned int badpages[1];
	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),
111	};
112
113	#define SWAP_CLUSTER_MAX 32
114
115	#define SWAP_MAP_MAX 0x7fff
116	#define SWAP_MAP_BAD 0x8000
117
118	/*
119	* The in-memory structure used to track swap areas.
120	* extent_list.prev points at the lowest-index extent. That list is
121	* sorted.
122	*/
123	struct swap_info_struct {
124	unsigned int flags;
125	spinlock_t sdev_lock;
126	struct file *swap_file;
127	struct block_device *bdev;
128	struct list_head extent_list;
129	int nr_extents;
130	struct swap_extent *curr_swap_extent;
131	unsigned old_block_size;
132	unsigned short * swap_map;
133	unsigned int lowest_bit;
134	unsigned int highest_bit;
135	unsigned int cluster_next;
136	unsigned int cluster_nr;
137	int prio; /* swap priority */
138	int pages;
139	unsigned long max;
140	unsigned long inuse_pages;
141	int next; /* next entry on swap list */
142	};
143
144	struct swap_list_t {
145	int head; /* head of priority-ordered swapfile list */
146	int next; /* swapfile to be used next */
147	};
148
149	/* Swap 50% full? Release swapcache more aggressively.. */
150	#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
151
152	/* linux/mm/oom_kill.c */
79b9ce31	153	extern void out_of_memory(unsigned int __nocast gfp_mask, int order);
1da177e4 LT	154
	155	/* linux/mm/memory.c */
	156	extern void swapin_readahead(swp_entry_t, unsigned long, struct vm_area_struct *);
	157
	158	/* linux/mm/page_alloc.c */
	159	extern unsigned long totalram_pages;
	160	extern unsigned long totalhigh_pages;
	161	extern long nr_swap_pages;
	162	extern unsigned int nr_free_pages(void);
	163	extern unsigned int nr_free_pages_pgdat(pg_data_t *pgdat);
	164	extern unsigned int nr_free_buffer_pages(void);
	165	extern unsigned int nr_free_pagecache_pages(void);
	166
	167	/* linux/mm/swap.c */
	168	extern void FASTCALL(lru_cache_add(struct page *));
	169	extern void FASTCALL(lru_cache_add_active(struct page *));
	170	extern void FASTCALL(activate_page(struct page *));
	171	extern void FASTCALL(mark_page_accessed(struct page *));
	172	extern void lru_add_drain(void);
	173	extern int rotate_reclaimable_page(struct page *page);
	174	extern void swap_setup(void);
	175
	176	/* linux/mm/vmscan.c */
1ad539b2	177	extern int try_to_free_pages(struct zone **, unsigned int);
753ee728	178	extern int zone_reclaim(struct zone *, unsigned int, unsigned int);
1da177e4 LT	179	extern int shrink_all_memory(int);
	180	extern int vm_swappiness;
	181
	182	#ifdef CONFIG_MMU
	183	/* linux/mm/shmem.c */
	184	extern int shmem_unuse(swp_entry_t entry, struct page *page);
	185	#endif /* CONFIG_MMU */
	186
	187	extern void swap_unplug_io_fn(struct backing_dev_info , struct page );
	188
	189	#ifdef CONFIG_SWAP
	190	/* linux/mm/page_io.c */
	191	extern int swap_readpage(struct file , struct page );
	192	extern int swap_writepage(struct page page, struct writeback_control wbc);
	193	extern int rw_swap_page_sync(int, swp_entry_t, struct page *);
	194
	195	/* linux/mm/swap_state.c */
	196	extern struct address_space swapper_space;
	197	#define total_swapcache_pages swapper_space.nrpages
	198	extern void show_swap_cache_info(void);
	199	extern int add_to_swap(struct page *);
	200	extern void __delete_from_swap_cache(struct page *);
	201	extern void delete_from_swap_cache(struct page *);
	202	extern int move_to_swap_cache(struct page *, swp_entry_t);
	203	extern int move_from_swap_cache(struct page *, unsigned long,
	204	struct address_space *);
	205	extern void free_page_and_swap_cache(struct page *);
	206	extern void free_pages_and_swap_cache(struct page **, int);
	207	extern struct page * lookup_swap_cache(swp_entry_t);
	208	extern struct page * read_swap_cache_async(swp_entry_t, struct vm_area_struct *vma,
	209	unsigned long addr);
	210	/* linux/mm/swapfile.c */
	211	extern long total_swap_pages;
	212	extern unsigned int nr_swapfiles;
	213	extern struct swap_info_struct swap_info[];
	214	extern void si_swapinfo(struct sysinfo *);
	215	extern swp_entry_t get_swap_page(void);
	216	extern int swap_duplicate(swp_entry_t);
	217	extern int valid_swaphandles(swp_entry_t, unsigned long *);
	218	extern void swap_free(swp_entry_t);
	219	extern void free_swap_and_cache(swp_entry_t);
	220	extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
	221	extern struct swap_info_struct *get_swap_info_struct(unsigned);
	222	extern int can_share_swap_page(struct page *);
	223	extern int remove_exclusive_swap_page(struct page *);
	224	struct backing_dev_info;
	225
	226	extern struct swap_list_t swap_list;
	227	extern spinlock_t swaplock;
	228
	229	#define swap_list_lock() spin_lock(&swaplock)
	230	#define swap_list_unlock() spin_unlock(&swaplock)
	231	#define swap_device_lock(p) spin_lock(&p->sdev_lock)
	232	#define swap_device_unlock(p) spin_unlock(&p->sdev_lock)
	233
	234	/* linux/mm/thrash.c */
	235	extern struct mm_struct * swap_token_mm;
	236	extern unsigned long swap_token_default_timeout;
	237	extern void grab_swap_token(void);
	238	extern void __put_swap_token(struct mm_struct *);
	239
	240	static inline int has_swap_token(struct mm_struct *mm)
	241	{
	242	return (mm == swap_token_mm);
243	}
244
245	static inline void put_swap_token(struct mm_struct *mm)
246	{
247	if (has_swap_token(mm))
248	__put_swap_token(mm);
249	}
250
251	#else /* CONFIG_SWAP */
252
253	#define total_swap_pages 0
254	#define total_swapcache_pages 0UL
255
256	#define si_swapinfo(val) \
257	do { (val)->freeswap = (val)->totalswap = 0; } while (0)
258	#define free_page_and_swap_cache(page) \
259	page_cache_release(page)
260	#define free_pages_and_swap_cache(pages, nr) \
261	release_pages((pages), (nr), 0);
262
263	#define show_swap_cache_info() /NOTHING/
264	#define free_swap_and_cache(swp) /NOTHING/
265	#define swap_duplicate(swp) /NOTHING/
266	#define swap_free(swp) /NOTHING/
267	#define read_swap_cache_async(swp,vma,addr) NULL
268	#define lookup_swap_cache(swp) NULL
269	#define valid_swaphandles(swp, off) 0
270	#define can_share_swap_page(p) 0
271	#define move_to_swap_cache(p, swp) 1
272	#define move_from_swap_cache(p, i, m) 1
273	#define __delete_from_swap_cache(p) /NOTHING/
274	#define delete_from_swap_cache(p) /NOTHING/
275	#define swap_token_default_timeout 0
276
277	static inline int remove_exclusive_swap_page(struct page *p)
278	{
279	return 0;
280	}
281
282	static inline swp_entry_t get_swap_page(void)
283	{
284	swp_entry_t entry;
285	entry.val = 0;
286	return entry;
287	}
288
289	/* linux/mm/thrash.c */
290	#define put_swap_token(x) do { } while(0)
291	#define grab_swap_token() do { } while(0)
292	#define has_swap_token(x) 0
293
294	#endif /* CONFIG_SWAP */
295	#endif /* __KERNEL__*/
296	#endif /* _LINUX_SWAP_H */