[mirror_ubuntu-zesty-kernel.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 <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)
/* 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)			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	10
1da177e4 LT	11	#include <asm/atomic.h>
	12	#include <asm/page.h>
	13
	14	#define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
	15	#define SWAP_FLAG_PRIO_MASK 0x7fff
	16	#define SWAP_FLAG_PRIO_SHIFT 0
	17
	18	static inline int current_is_kswapd(void)
	19	{
	20	return current->flags & PF_KSWAPD;
	21	}
	22
	23	/*
	24	* MAX_SWAPFILES defines the maximum number of swaptypes: things which can
	25	* be swapped to. The swap type and the offset into that swap type are
	26	* encoded into pte's and into pgoff_t's in the swapcache. Using five bits
	27	* for the type means that the maximum number of swapcache pages is 27 bits
	28	* on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
	29	* the type/offset into the pte as 5/27 as well.
	30	*/
	31	#define MAX_SWAPFILES_SHIFT 5
	32	#define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
	33
	34	/*
	35	* Magic header for a swap area. The first part of the union is
	36	* what the swap magic looks like for the old (limited to 128MB)
	37	* swap area format, the second part of the union adds - in the
	38	* old reserved area - some extra information. Note that the first
	39	* kilobyte is reserved for boot loader or disk label stuff...
	40	*
	41	* Having the magic at the end of the PAGE_SIZE makes detecting swap
	42	* areas somewhat tricky on machines that support multiple page sizes.
	43	* For 2.5 we'll probably want to move the magic to just beyond the
	44	* bootbits...
	45	*/
	46	union swap_header {
	47	struct {
	48	char reserved[PAGE_SIZE - 10];
	49	char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
	50	} magic;
	51	struct {
	52	char bootbits[1024]; /* Space for disklabel etc. */
	53	unsigned int version;
	54	unsigned int last_page;
	55	unsigned int nr_badpages;
	56	unsigned int padding[125];
	57	unsigned int badpages[1];
	58	} info;
	59	};
	60
	61	/* A swap entry has to fit into a "unsigned long", as
	62	* the entry is hidden in the "index" field of the
	63	* swapper address space.
	64	*/
	65	typedef struct {
	66	unsigned long val;
	67	} swp_entry_t;
	68
	69	/*
	70	* current->reclaim_state points to one of these when a task is running
	71	* memory reclaim
	72	*/
	73	struct reclaim_state {
	74	unsigned long reclaimed_slab;
75	};
76
77	#ifdef __KERNEL__
78
79	struct address_space;
80	struct sysinfo;
81	struct writeback_control;
82	struct zone;
83
84	/*
85	* A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
86	* disk blocks. A list of swap extents maps the entire swapfile. (Where the
87	* term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
88	* from setup, they're handled identically.
89	*
90	* We always assume that blocks are of size PAGE_SIZE.
91	*/
92	struct swap_extent {
93	struct list_head list;
94	pgoff_t start_page;
95	pgoff_t nr_pages;
96	sector_t start_block;
97	};
98
99	/*
100	* Max bad pages in the new format..
101	*/
102	#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
103	#define MAX_SWAP_BADPAGES \
104	((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
105
106	enum {
107	SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
108	SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
109	SWP_ACTIVE = (SWP_USED \| SWP_WRITEOK),
110	};
111
112	#define SWAP_CLUSTER_MAX 32
113
114	#define SWAP_MAP_MAX 0x7fff
115	#define SWAP_MAP_BAD 0x8000
116
117	/*
118	* The in-memory structure used to track swap areas.
119	* extent_list.prev points at the lowest-index extent. That list is
120	* sorted.
121	*/
122	struct swap_info_struct {
123	unsigned int flags;
124	spinlock_t sdev_lock;
125	struct file *swap_file;
126	struct block_device *bdev;
127	struct list_head extent_list;
128	int nr_extents;
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;
136	int prio; /* swap priority */
137	int pages;
138	unsigned long max;
139	unsigned long inuse_pages;
140	int next; /* next entry on swap list */
141	};
142
143	struct swap_list_t {
144	int head; /* head of priority-ordered swapfile list */
145	int next; /* swapfile to be used next */
146	};
147
148	/* Swap 50% full? Release swapcache more aggressively.. */
149	#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
150
151	/* linux/mm/oom_kill.c */
79b9ce31	152	extern void out_of_memory(unsigned int __nocast gfp_mask, int order);
1da177e4 LT	153
	154	/* linux/mm/memory.c */
	155	extern void swapin_readahead(swp_entry_t, unsigned long, struct vm_area_struct *);
	156
	157	/* linux/mm/page_alloc.c */
	158	extern unsigned long totalram_pages;
	159	extern unsigned long totalhigh_pages;
	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);
	172	extern int rotate_reclaimable_page(struct page *page);
	173	extern void swap_setup(void);
	174
	175	/* linux/mm/vmscan.c */
1ad539b2	176	extern int try_to_free_pages(struct zone **, unsigned int);
753ee728	177	extern int zone_reclaim(struct zone *, unsigned int, unsigned int);
1da177e4 LT	178	extern int shrink_all_memory(int);
	179	extern int vm_swappiness;
	180
	181	#ifdef CONFIG_MMU
	182	/* linux/mm/shmem.c */
	183	extern int shmem_unuse(swp_entry_t entry, struct page *page);
	184	#endif /* CONFIG_MMU */
	185
	186	extern void swap_unplug_io_fn(struct backing_dev_info , struct page );
	187
	188	#ifdef CONFIG_SWAP
	189	/* linux/mm/page_io.c */
	190	extern int swap_readpage(struct file , struct page );
	191	extern int swap_writepage(struct page page, struct writeback_control wbc);
	192	extern int rw_swap_page_sync(int, swp_entry_t, struct page *);
	193
	194	/* linux/mm/swap_state.c */
	195	extern struct address_space swapper_space;
	196	#define total_swapcache_pages swapper_space.nrpages
	197	extern void show_swap_cache_info(void);
	198	extern int add_to_swap(struct page *);
	199	extern void __delete_from_swap_cache(struct page *);
	200	extern void delete_from_swap_cache(struct page *);
	201	extern int move_to_swap_cache(struct page *, swp_entry_t);
	202	extern int move_from_swap_cache(struct page *, unsigned long,
	203	struct address_space *);
	204	extern void free_page_and_swap_cache(struct page *);
	205	extern void free_pages_and_swap_cache(struct page **, int);
	206	extern struct page * lookup_swap_cache(swp_entry_t);
	207	extern struct page * read_swap_cache_async(swp_entry_t, struct vm_area_struct *vma,
	208	unsigned long addr);
	209	/* linux/mm/swapfile.c */
	210	extern long total_swap_pages;
	211	extern unsigned int nr_swapfiles;
	212	extern struct swap_info_struct swap_info[];
	213	extern void si_swapinfo(struct sysinfo *);
	214	extern swp_entry_t get_swap_page(void);
	215	extern int swap_duplicate(swp_entry_t);
	216	extern int valid_swaphandles(swp_entry_t, unsigned long *);
	217	extern void swap_free(swp_entry_t);
	218	extern void free_swap_and_cache(swp_entry_t);
	219	extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
	220	extern struct swap_info_struct *get_swap_info_struct(unsigned);
	221	extern int can_share_swap_page(struct page *);
	222	extern int remove_exclusive_swap_page(struct page *);
	223	struct backing_dev_info;
	224
	225	extern struct swap_list_t swap_list;
	226	extern spinlock_t swaplock;
	227
	228	#define swap_list_lock() spin_lock(&swaplock)
	229	#define swap_list_unlock() spin_unlock(&swaplock)
	230	#define swap_device_lock(p) spin_lock(&p->sdev_lock)
	231	#define swap_device_unlock(p) spin_unlock(&p->sdev_lock)
	232
	233	/* linux/mm/thrash.c */
	234	extern struct mm_struct * swap_token_mm;
	235	extern unsigned long swap_token_default_timeout;
	236	extern void grab_swap_token(void);
	237	extern void __put_swap_token(struct mm_struct *);
	238
	239	static inline int has_swap_token(struct mm_struct *mm)
	240	{
	241	return (mm == swap_token_mm);
242	}
243
244	static inline void put_swap_token(struct mm_struct *mm)
245	{
246	if (has_swap_token(mm))
247	__put_swap_token(mm);
248	}
249
250	#else /* CONFIG_SWAP */
251
252	#define total_swap_pages 0
253	#define total_swapcache_pages 0UL
254
255	#define si_swapinfo(val) \
256	do { (val)->freeswap = (val)->totalswap = 0; } while (0)
9ae5b3c7 OH	257	/* only sparc can not include linux/pagemap.h in this file
9ae5b3c7 OH	258	* so leave page_cache_release and release_pages undeclared... */
1da177e4 LT	259	#define free_page_and_swap_cache(page) \
	260	page_cache_release(page)
	261	#define free_pages_and_swap_cache(pages, nr) \
	262	release_pages((pages), (nr), 0);
	263
	264	#define show_swap_cache_info() /NOTHING/
	265	#define free_swap_and_cache(swp) /NOTHING/
	266	#define swap_duplicate(swp) /NOTHING/
	267	#define swap_free(swp) /NOTHING/
	268	#define read_swap_cache_async(swp,vma,addr) NULL
	269	#define lookup_swap_cache(swp) NULL
	270	#define valid_swaphandles(swp, off) 0
	271	#define can_share_swap_page(p) 0
	272	#define move_to_swap_cache(p, swp) 1
	273	#define move_from_swap_cache(p, i, m) 1
	274	#define __delete_from_swap_cache(p) /NOTHING/
	275	#define delete_from_swap_cache(p) /NOTHING/
	276	#define swap_token_default_timeout 0
	277
	278	static inline int remove_exclusive_swap_page(struct page *p)
	279	{
	280	return 0;
	281	}
	282
	283	static inline swp_entry_t get_swap_page(void)
	284	{
	285	swp_entry_t entry;
	286	entry.val = 0;
	287	return entry;
	288	}
	289
	290	/* linux/mm/thrash.c */
	291	#define put_swap_token(x) do { } while(0)
	292	#define grab_swap_token() do { } while(0)
	293	#define has_swap_token(x) 0
	294
	295	#endif /* CONFIG_SWAP */
	296	#endif /* __KERNEL__*/
	297	#endif /* _LINUX_SWAP_H */