[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/memcontrol.h>
#include <linux/sched.h>
#include <linux/node.h>

#include <linux/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
#define SWAP_FLAG_DISCARD	0x10000 /* discard swap cluster after use */

#define SWAP_FLAGS_VALID	(SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \
				 SWAP_FLAG_DISCARD)

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

/*
 * Use some of the swap files numbers for other purposes. This
 * is a convenient way to hook into the VM to trigger special
 * actions on faults.
 */

/*
 * NUMA node memory migration support
 */
#ifdef CONFIG_MIGRATION
#define SWP_MIGRATION_NUM 2
#define SWP_MIGRATION_READ	(MAX_SWAPFILES + SWP_HWPOISON_NUM)
#define SWP_MIGRATION_WRITE	(MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
#else
#define SWP_MIGRATION_NUM 0
#endif

/*
 * Handling of hardware poisoned pages with memory corruption.
 */
#ifdef CONFIG_MEMORY_FAILURE
#define SWP_HWPOISON_NUM 1
#define SWP_HWPOISON		MAX_SWAPFILES
#else
#define SWP_HWPOISON_NUM 0
#endif

#define MAX_SWAPFILES \
	((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)

/*
 * 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_DISCARDABLE = (1 << 2),	/* swapon+blkdev support discard */
	SWP_DISCARDING	= (1 << 3),	/* now discarding a free cluster */
	SWP_SOLIDSTATE	= (1 << 4),	/* blkdev seeks are cheap */
	SWP_CONTINUED	= (1 << 5),	/* swap_map has count continuation */
	SWP_BLKDEV	= (1 << 6),	/* its a block device */
					/* add others here before... */
	SWP_SCANNING	= (1 << 8),	/* refcount in scan_swap_map */
};

#define SWAP_CLUSTER_MAX 32
#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX

/*
 * Ratio between the present memory in the zone and the "gap" that
 * we're allowing kswapd to shrink in addition to the per-zone high
 * wmark, even for zones that already have the high wmark satisfied,
 * in order to provide better per-zone lru behavior. We are ok to
 * spend not more than 1% of the memory for this zone balancing "gap".
 */
#define KSWAPD_ZONE_BALANCE_GAP_RATIO 100

#define SWAP_MAP_MAX	0x3e	/* Max duplication count, in first swap_map */
#define SWAP_MAP_BAD	0x3f	/* Note pageblock is bad, in first swap_map */
#define SWAP_HAS_CACHE	0x40	/* Flag page is cached, in first swap_map */
#define SWAP_CONT_MAX	0x7f	/* Max count, in each swap_map continuation */
#define COUNT_CONTINUED	0x80	/* See swap_map continuation for full count */
#define SWAP_MAP_SHMEM	0xbf	/* Owned by shmem/tmpfs, in first swap_map */

/*
 * The in-memory structure used to track swap areas.
 */
struct swap_info_struct {
	unsigned long	flags;		/* SWP_USED etc: see above */
	signed short	prio;		/* swap priority of this type */
	signed char	type;		/* strange name for an index */
	signed char	next;		/* next type on the swap list */
	unsigned int	max;		/* extent of the swap_map */
	unsigned char *swap_map;	/* vmalloc'ed array of usage counts */
	unsigned int lowest_bit;	/* index of first free in swap_map */
	unsigned int highest_bit;	/* index of last free in swap_map */
	unsigned int pages;		/* total of usable pages of swap */
	unsigned int inuse_pages;	/* number of those currently in use */
	unsigned int cluster_next;	/* likely index for next allocation */
	unsigned int cluster_nr;	/* countdown to next cluster search */
	unsigned int lowest_alloc;	/* while preparing discard cluster */
	unsigned int highest_alloc;	/* while preparing discard cluster */
	struct swap_extent *curr_swap_extent;
	struct swap_extent first_swap_extent;
	struct block_device *bdev;	/* swap device or bdev of swap file */
	struct file *swap_file;		/* seldom referenced */
	unsigned int old_block_size;	/* seldom referenced */
#ifdef CONFIG_FRONTSWAP
	unsigned long *frontswap_map;	/* frontswap in-use, one bit per page */
	atomic_t frontswap_pages;	/* frontswap pages in-use counter */
#endif
};

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 unsigned long dirty_balance_reserve;
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 __lru_cache_add(struct page *, enum lru_list lru);
extern void lru_cache_add_lru(struct page *, enum lru_list lru);
extern void lru_add_page_tail(struct page *page, struct page *page_tail,
			      struct lruvec *lruvec);
extern void activate_page(struct page *);
extern void mark_page_accessed(struct page *);
extern void lru_add_drain(void);
extern void lru_add_drain_cpu(int cpu);
extern int lru_add_drain_all(void);
extern void rotate_reclaimable_page(struct page *page);
extern void deactivate_page(struct page *page);
extern void swap_setup(void);

extern void add_page_to_unevictable_list(struct page *page);

/**
 * lru_cache_add: add a page to the page lists
 * @page: the page to add
 */
static inline void lru_cache_add_anon(struct page *page)
{
	__lru_cache_add(page, LRU_INACTIVE_ANON);
}

static inline void lru_cache_add_file(struct page *page)
{
	__lru_cache_add(page, LRU_INACTIVE_FILE);
}

/* linux/mm/vmscan.c */
extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
					gfp_t gfp_mask, nodemask_t *mask);
extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
						  gfp_t gfp_mask, bool noswap);
extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
						gfp_t gfp_mask, bool noswap,
						struct zone *zone,
						unsigned long *nr_scanned);
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 page_evictable(struct page *page, struct vm_area_struct *vma);
extern void check_move_unevictable_pages(struct page **, int nr_pages);

extern unsigned long scan_unevictable_pages;
extern int scan_unevictable_handler(struct ctl_table *, int,
					void __user *, size_t *, loff_t *);
#ifdef CONFIG_NUMA
extern int scan_unevictable_register_node(struct node *node);
extern void scan_unevictable_unregister_node(struct node *node);
#else
static inline int scan_unevictable_register_node(struct node *node)
{
	return 0;
}
static inline void scan_unevictable_unregister_node(struct node *node)
{
}
#endif

extern int kswapd_run(int nid);
extern void kswapd_stop(int nid);
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
extern int mem_cgroup_swappiness(struct mem_cgroup *mem);
#else
static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
{
	return vm_swappiness;
}
#endif
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
extern void mem_cgroup_uncharge_swap(swp_entry_t ent);
#else
static inline void mem_cgroup_uncharge_swap(swp_entry_t ent)
{
}
#endif
#ifdef CONFIG_SWAP
/* linux/mm/page_io.c */
extern int swap_readpage(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 *);
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 nr_swap_pages;
extern long total_swap_pages;
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 add_swap_count_continuation(swp_entry_t, gfp_t);
extern void swap_shmem_alloc(swp_entry_t);
extern int swap_duplicate(swp_entry_t);
extern int swapcache_prepare(swp_entry_t);
extern void swap_free(swp_entry_t);
extern void swapcache_free(swp_entry_t, struct page *page);
extern int 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 page *, struct block_device **);
extern sector_t swapdev_block(int, pgoff_t);
extern int page_swapcount(struct page *);
extern int reuse_swap_page(struct page *);
extern int try_to_free_swap(struct page *);
struct backing_dev_info;

#ifdef CONFIG_CGROUP_MEM_RES_CTLR
extern void
mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout);
#else
static inline void
mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
{
}
#endif

#else /* CONFIG_SWAP */

#define nr_swap_pages				0L
#define total_swap_pages			0L
#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)
{
}

#define free_swap_and_cache(swp)	is_migration_entry(swp)
#define swapcache_prepare(swp)		is_migration_entry(swp)

static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
{
	return 0;
}

static inline void swap_shmem_alloc(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 void swapcache_free(swp_entry_t swp, struct page *page)
{
}

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 int swap_writepage(struct page *p, struct writeback_control *wbc)
{
	return 0;
}

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

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

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)
{
}

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

#define reuse_swap_page(page)	(page_mapcount(page) == 1)

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

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

static inline void
mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
{
}

#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>
66e1707b	8	#include <linux/memcontrol.h>
1da177e4	9	#include <linux/sched.h>
af936a16	10	#include <linux/node.h>
542d1c88	11
60063497	12	#include <linux/atomic.h>
1da177e4 LT	13	#include <asm/page.h>
1da177e4 LT	14
8bc719d3 MS	15	struct notifier_block;
8bc719d3 MS	16
ab954160 AM	17	struct bio;
ab954160 AM	18
1da177e4 LT	19	#define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
	20	#define SWAP_FLAG_PRIO_MASK 0x7fff
	21	#define SWAP_FLAG_PRIO_SHIFT 0
33994466	22	#define SWAP_FLAG_DISCARD 0x10000 /* discard swap cluster after use */
1da177e4	23
d15cab97 HD	24	#define SWAP_FLAGS_VALID (SWAP_FLAG_PRIO_MASK \| SWAP_FLAG_PREFER \| \
	25	SWAP_FLAG_DISCARD)
	26
1da177e4 LT	27	static inline int current_is_kswapd(void)
	28	{
	29	return current->flags & PF_KSWAPD;
	30	}
	31
	32	/*
	33	* MAX_SWAPFILES defines the maximum number of swaptypes: things which can
	34	* be swapped to. The swap type and the offset into that swap type are
	35	* encoded into pte's and into pgoff_t's in the swapcache. Using five bits
	36	* for the type means that the maximum number of swapcache pages is 27 bits
	37	* on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
	38	* the type/offset into the pte as 5/27 as well.
	39	*/
	40	#define MAX_SWAPFILES_SHIFT 5
a7420aa5 AK	41
	42	/*
	43	* Use some of the swap files numbers for other purposes. This
	44	* is a convenient way to hook into the VM to trigger special
	45	* actions on faults.
	46	*/
	47
	48	/*
	49	* NUMA node memory migration support
	50	*/
	51	#ifdef CONFIG_MIGRATION
	52	#define SWP_MIGRATION_NUM 2
	53	#define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
	54	#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
0697212a	55	#else
a7420aa5	56	#define SWP_MIGRATION_NUM 0
0697212a	57	#endif
1da177e4	58
a7420aa5 AK	59	/*
	60	* Handling of hardware poisoned pages with memory corruption.
	61	*/
	62	#ifdef CONFIG_MEMORY_FAILURE
	63	#define SWP_HWPOISON_NUM 1
	64	#define SWP_HWPOISON MAX_SWAPFILES
	65	#else
	66	#define SWP_HWPOISON_NUM 0
	67	#endif
	68
	69	#define MAX_SWAPFILES \
	70	((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)
	71
1da177e4 LT	72	/*
	73	* Magic header for a swap area. The first part of the union is
	74	* what the swap magic looks like for the old (limited to 128MB)
	75	* swap area format, the second part of the union adds - in the
	76	* old reserved area - some extra information. Note that the first
	77	* kilobyte is reserved for boot loader or disk label stuff...
	78	*
	79	* Having the magic at the end of the PAGE_SIZE makes detecting swap
	80	* areas somewhat tricky on machines that support multiple page sizes.
	81	* For 2.5 we'll probably want to move the magic to just beyond the
	82	* bootbits...
	83	*/
	84	union swap_header {
	85	struct {
	86	char reserved[PAGE_SIZE - 10];
	87	char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
	88	} magic;
	89	struct {
e8f03d02 AD	90	char bootbits[1024]; /* Space for disklabel etc. */
	91	__u32 version;
	92	__u32 last_page;
	93	__u32 nr_badpages;
	94	unsigned char sws_uuid[16];
	95	unsigned char sws_volume[16];
	96	__u32 padding[117];
	97	__u32 badpages[1];
1da177e4 LT	98	} info;
	99	};
	100
	101	/* A swap entry has to fit into a "unsigned long", as
	102	* the entry is hidden in the "index" field of the
	103	* swapper address space.
	104	*/
	105	typedef struct {
	106	unsigned long val;
	107	} swp_entry_t;
	108
	109	/*
	110	* current->reclaim_state points to one of these when a task is running
	111	* memory reclaim
	112	*/
	113	struct reclaim_state {
	114	unsigned long reclaimed_slab;
	115	};
	116
	117	#ifdef __KERNEL__
	118
	119	struct address_space;
	120	struct sysinfo;
	121	struct writeback_control;
	122	struct zone;
	123
	124	/*
	125	* A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
	126	* disk blocks. A list of swap extents maps the entire swapfile. (Where the
	127	* term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
	128	* from setup, they're handled identically.
	129	*
	130	* We always assume that blocks are of size PAGE_SIZE.
	131	*/
	132	struct swap_extent {
	133	struct list_head list;
	134	pgoff_t start_page;
	135	pgoff_t nr_pages;
	136	sector_t start_block;
	137	};
	138
	139	/*
	140	* Max bad pages in the new format..
	141	*/
	142	#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
	143	#define MAX_SWAP_BADPAGES \
	144	((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
	145
	146	enum {
	147	SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
	148	SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
33994466	149	SWP_DISCARDABLE = (1 << 2), /* swapon+blkdev support discard */
7992fde7	150	SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
20137a49	151	SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
570a335b	152	SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
b2725643	153	SWP_BLKDEV = (1 << 6), /* its a block device */
52b7efdb HD	154	/* add others here before... */
52b7efdb HD	155	SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
1da177e4 LT	156	};
	157
	158	#define SWAP_CLUSTER_MAX 32
748446bb	159	#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
1da177e4	160
8afdcece MG	161	/*
	162	* Ratio between the present memory in the zone and the "gap" that
	163	* we're allowing kswapd to shrink in addition to the per-zone high
	164	* wmark, even for zones that already have the high wmark satisfied,
	165	* in order to provide better per-zone lru behavior. We are ok to
	166	* spend not more than 1% of the memory for this zone balancing "gap".
	167	*/
	168	#define KSWAPD_ZONE_BALANCE_GAP_RATIO 100
	169
570a335b HD	170	#define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */
	171	#define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */
	172	#define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
	173	#define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */
	174	#define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */
aaa46865	175	#define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */
253d553b	176
1da177e4 LT	177	/*
1da177e4 LT	178	* The in-memory structure used to track swap areas.
1da177e4 LT	179	*/
1da177e4 LT	180	struct swap_info_struct {
efa90a98 HD	181	unsigned long flags; /* SWP_USED etc: see above */
	182	signed short prio; /* swap priority of this type */
	183	signed char type; /* strange name for an index */
	184	signed char next; /* next type on the swap list */
7509765a HD	185	unsigned int max; /* extent of the swap_map */
	186	unsigned char swap_map; / vmalloc'ed array of usage counts */
	187	unsigned int lowest_bit; /* index of first free in swap_map */
	188	unsigned int highest_bit; /* index of last free in swap_map */
	189	unsigned int pages; /* total of usable pages of swap */
	190	unsigned int inuse_pages; /* number of those currently in use */
	191	unsigned int cluster_next; /* likely index for next allocation */
	192	unsigned int cluster_nr; /* countdown to next cluster search */
7992fde7 HD	193	unsigned int lowest_alloc; /* while preparing discard cluster */
7992fde7 HD	194	unsigned int highest_alloc; /* while preparing discard cluster */
7509765a HD	195	struct swap_extent *curr_swap_extent;
	196	struct swap_extent first_swap_extent;
	197	struct block_device bdev; / swap device or bdev of swap file */
	198	struct file swap_file; / seldom referenced */
	199	unsigned int old_block_size; /* seldom referenced */
38b5faf4 DM	200	#ifdef CONFIG_FRONTSWAP
	201	unsigned long frontswap_map; / frontswap in-use, one bit per page */
	202	atomic_t frontswap_pages; /* frontswap pages in-use counter */
	203	#endif
1da177e4 LT	204	};
	205
	206	struct swap_list_t {
	207	int head; /* head of priority-ordered swapfile list */
	208	int next; /* swapfile to be used next */
	209	};
	210
	211	/* Swap 50% full? Release swapcache more aggressively.. */
	212	#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
	213
1da177e4 LT	214	/* linux/mm/page_alloc.c */
1da177e4 LT	215	extern unsigned long totalram_pages;
cb45b0e9	216	extern unsigned long totalreserve_pages;
ab8fabd4	217	extern unsigned long dirty_balance_reserve;
1da177e4 LT	218	extern unsigned int nr_free_buffer_pages(void);
	219	extern unsigned int nr_free_pagecache_pages(void);
	220
96177299 CL	221	/* Definition of global_page_state not available yet */
	222	#define nr_free_pages() global_page_state(NR_FREE_PAGES)
	223
	224
1da177e4	225	/* linux/mm/swap.c */
f04e9ebb KM	226	extern void __lru_cache_add(struct page *, enum lru_list lru);
f04e9ebb KM	227	extern void lru_cache_add_lru(struct page *, enum lru_list lru);
fa9add64 HD	228	extern void lru_add_page_tail(struct page page, struct page page_tail,
fa9add64 HD	229	struct lruvec *lruvec);
b3c97528 HH	230	extern void activate_page(struct page *);
b3c97528 HH	231	extern void mark_page_accessed(struct page *);
1da177e4	232	extern void lru_add_drain(void);
f0cb3c76	233	extern void lru_add_drain_cpu(int cpu);
053837fc	234	extern int lru_add_drain_all(void);
ac6aadb2	235	extern void rotate_reclaimable_page(struct page *page);
31560180	236	extern void deactivate_page(struct page *page);
1da177e4 LT	237	extern void swap_setup(void);
1da177e4 LT	238
894bc310 LS	239	extern void add_page_to_unevictable_list(struct page *page);
894bc310 LS	240
f04e9ebb KM	241	/**
	242	* lru_cache_add: add a page to the page lists
	243	* @page: the page to add
	244	*/
4f98a2fe	245	static inline void lru_cache_add_anon(struct page *page)
f04e9ebb	246	{
4f98a2fe	247	__lru_cache_add(page, LRU_INACTIVE_ANON);
f04e9ebb KM	248	}
f04e9ebb KM	249
4f98a2fe RR	250	static inline void lru_cache_add_file(struct page *page)
	251	{
	252	__lru_cache_add(page, LRU_INACTIVE_FILE);
	253	}
	254
1da177e4	255	/* linux/mm/vmscan.c */
dac1d27b	256	extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
327c0e96	257	gfp_t gfp_mask, nodemask_t *mask);
f3fd4a61	258	extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
185efc0f JW	259	extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
	260	gfp_t gfp_mask, bool noswap);
	261	extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
	262	gfp_t gfp_mask, bool noswap,
	263	struct zone *zone,
	264	unsigned long *nr_scanned);
69e05944	265	extern unsigned long shrink_all_memory(unsigned long nr_pages);
1da177e4	266	extern int vm_swappiness;
b20a3503	267	extern int remove_mapping(struct address_space mapping, struct page page);
bd1e22b8	268	extern long vm_total_pages;
b20a3503	269
9eeff239 CL	270	#ifdef CONFIG_NUMA
9eeff239 CL	271	extern int zone_reclaim_mode;
9614634f	272	extern int sysctl_min_unmapped_ratio;
0ff38490	273	extern int sysctl_min_slab_ratio;
9eeff239 CL	274	extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
	275	#else
	276	#define zone_reclaim_mode 0
	277	static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
	278	{
	279	return 0;
	280	}
	281	#endif
	282
894bc310	283	extern int page_evictable(struct page page, struct vm_area_struct vma);
24513264	284	extern void check_move_unevictable_pages(struct page **, int nr_pages);
af936a16 LS	285
af936a16 LS	286	extern unsigned long scan_unevictable_pages;
8d65af78	287	extern int scan_unevictable_handler(struct ctl_table *, int,
af936a16	288	void __user , size_t , loff_t *);
e4455abb	289	#ifdef CONFIG_NUMA
af936a16 LS	290	extern int scan_unevictable_register_node(struct node *node);
af936a16 LS	291	extern void scan_unevictable_unregister_node(struct node *node);
e4455abb TLSC	292	#else
	293	static inline int scan_unevictable_register_node(struct node *node)
	294	{
	295	return 0;
	296	}
	297	static inline void scan_unevictable_unregister_node(struct node *node)
	298	{
	299	}
	300	#endif
894bc310	301
3218ae14	302	extern int kswapd_run(int nid);
8fe23e05	303	extern void kswapd_stop(int nid);
1f4c025b KH	304	#ifdef CONFIG_CGROUP_MEM_RES_CTLR
	305	extern int mem_cgroup_swappiness(struct mem_cgroup *mem);
	306	#else
	307	static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
	308	{
	309	return vm_swappiness;
	310	}
	311	#endif
dac23b0d MH	312	#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
	313	extern void mem_cgroup_uncharge_swap(swp_entry_t ent);
	314	#else
	315	static inline void mem_cgroup_uncharge_swap(swp_entry_t ent)
	316	{
	317	}
	318	#endif
1da177e4 LT	319	#ifdef CONFIG_SWAP
1da177e4 LT	320	/* linux/mm/page_io.c */
aca8bf32	321	extern int swap_readpage(struct page *);
1da177e4	322	extern int swap_writepage(struct page page, struct writeback_control wbc);
6712ecf8	323	extern void end_swap_bio_read(struct bio *bio, int err);
1da177e4 LT	324
	325	/* linux/mm/swap_state.c */
	326	extern struct address_space swapper_space;
	327	#define total_swapcache_pages swapper_space.nrpages
	328	extern void show_swap_cache_info(void);
ac47b003	329	extern int add_to_swap(struct page *);
73b1262f	330	extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
1da177e4 LT	331	extern void __delete_from_swap_cache(struct page *);
1da177e4 LT	332	extern void delete_from_swap_cache(struct page *);
1da177e4 LT	333	extern void free_page_and_swap_cache(struct page *);
1da177e4 LT	334	extern void free_pages_and_swap_cache(struct page **, int);
46017e95	335	extern struct page *lookup_swap_cache(swp_entry_t);
02098fea	336	extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
46017e95	337	struct vm_area_struct *vma, unsigned long addr);
02098fea	338	extern struct page *swapin_readahead(swp_entry_t, gfp_t,
46017e95 HD	339	struct vm_area_struct *vma, unsigned long addr);
46017e95 HD	340
1da177e4	341	/* linux/mm/swapfile.c */
b962716b	342	extern long nr_swap_pages;
1da177e4	343	extern long total_swap_pages;
1da177e4 LT	344	extern void si_swapinfo(struct sysinfo *);
1da177e4 LT	345	extern swp_entry_t get_swap_page(void);
910321ea	346	extern swp_entry_t get_swap_page_of_type(int);
570a335b	347	extern int add_swap_count_continuation(swp_entry_t, gfp_t);
aaa46865	348	extern void swap_shmem_alloc(swp_entry_t);
570a335b HD	349	extern int swap_duplicate(swp_entry_t);
570a335b HD	350	extern int swapcache_prepare(swp_entry_t);
1da177e4	351	extern void swap_free(swp_entry_t);
cb4b86ba	352	extern void swapcache_free(swp_entry_t, struct page *page);
2509ef26	353	extern int free_swap_and_cache(swp_entry_t);
7bf23687	354	extern int swap_type_of(dev_t, sector_t, struct block_device **);
f577eb30	355	extern unsigned int count_swap_pages(int, int);
d4906e1a	356	extern sector_t map_swap_page(struct page , struct block_device *);
3aef83e0	357	extern sector_t swapdev_block(int, pgoff_t);
bde05d1c	358	extern int page_swapcount(struct page *);
7b1fe597	359	extern int reuse_swap_page(struct page *);
a2c43eed	360	extern int try_to_free_swap(struct page *);
1da177e4 LT	361	struct backing_dev_info;
1da177e4 LT	362
d13d1443	363	#ifdef CONFIG_CGROUP_MEM_RES_CTLR
8a9478ca KH	364	extern void
8a9478ca KH	365	mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout);
d13d1443	366	#else
8c7c6e34	367	static inline void
8a9478ca	368	mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
8c7c6e34 KH	369	{
	370	}
	371	#endif
d13d1443	372
1da177e4 LT	373	#else /* CONFIG_SWAP */
1da177e4 LT	374
b962716b HD	375	#define nr_swap_pages 0L
b962716b HD	376	#define total_swap_pages 0L
1da177e4 LT	377	#define total_swapcache_pages 0UL
	378
	379	#define si_swapinfo(val) \
	380	do { (val)->freeswap = (val)->totalswap = 0; } while (0)
9ae5b3c7 OH	381	/* only sparc can not include linux/pagemap.h in this file
9ae5b3c7 OH	382	* so leave page_cache_release and release_pages undeclared... */
1da177e4 LT	383	#define free_page_and_swap_cache(page) \
	384	page_cache_release(page)
	385	#define free_pages_and_swap_cache(pages, nr) \
	386	release_pages((pages), (nr), 0);
	387
bd96b9eb CK	388	static inline void show_swap_cache_info(void)
	389	{
	390	}
	391
2509ef26	392	#define free_swap_and_cache(swp) is_migration_entry(swp)
cb4b86ba	393	#define swapcache_prepare(swp) is_migration_entry(swp)
bd96b9eb	394
570a335b	395	static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
355cfa73	396	{
570a335b HD	397	return 0;
	398	}
	399
aaa46865 HD	400	static inline void swap_shmem_alloc(swp_entry_t swp)
	401	{
	402	}
	403
570a335b HD	404	static inline int swap_duplicate(swp_entry_t swp)
	405	{
	406	return 0;
355cfa73 KH	407	}
355cfa73 KH	408
bd96b9eb CK	409	static inline void swap_free(swp_entry_t swp)
	410	{
	411	}
	412
cb4b86ba KH	413	static inline void swapcache_free(swp_entry_t swp, struct page *page)
	414	{
	415	}
	416
02098fea	417	static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
bd96b9eb CK	418	struct vm_area_struct *vma, unsigned long addr)
	419	{
	420	return NULL;
	421	}
	422
9fab5619 HD	423	static inline int swap_writepage(struct page p, struct writeback_control wbc)
	424	{
	425	return 0;
	426	}
	427
bd96b9eb CK	428	static inline struct page *lookup_swap_cache(swp_entry_t swp)
	429	{
	430	return NULL;
	431	}
	432
60371d97 HD	433	static inline int add_to_swap(struct page *page)
	434	{
	435	return 0;
	436	}
	437
73b1262f HD	438	static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
73b1262f HD	439	gfp_t gfp_mask)
bd96b9eb	440	{
73b1262f	441	return -1;
bd96b9eb CK	442	}
	443
	444	static inline void __delete_from_swap_cache(struct page *page)
	445	{
	446	}
	447
	448	static inline void delete_from_swap_cache(struct page *page)
	449	{
	450	}
	451
bde05d1c HD	452	static inline int page_swapcount(struct page *page)
	453	{
	454	return 0;
	455	}
	456
7b1fe597	457	#define reuse_swap_page(page) (page_mapcount(page) == 1)
1da177e4	458
a2c43eed	459	static inline int try_to_free_swap(struct page *page)
68a22394 RR	460	{
	461	return 0;
	462	}
	463
1da177e4 LT	464	static inline swp_entry_t get_swap_page(void)
	465	{
	466	swp_entry_t entry;
	467	entry.val = 0;
	468	return entry;
	469	}
	470
e767e056 DN	471	static inline void
	472	mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
	473	{
	474	}
	475
1da177e4 LT	476	#endif /* CONFIG_SWAP */
	477	#endif /* __KERNEL__*/
	478	#endif /* _LINUX_SWAP_H */