[mirror_ubuntu-bionic-kernel.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 <asm/atomic.h>
#include <asm/page.h>

struct notifier_block;

struct bio;

#define SWAP_FLAG_PREFER	0x8000	/* set if swap priority specified */
#define SWAP_FLAG_PRIO_MASK	0x7fff
#define SWAP_FLAG_PRIO_SHIFT	0

static inline int current_is_kswapd(void)
{
	return current->flags & PF_KSWAPD;
}

/*
 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
 * be swapped to.  The swap type and the offset into that swap type are
 * encoded into pte's and into pgoff_t's in the swapcache.  Using five bits
 * for the type means that the maximum number of swapcache pages is 27 bits
 * on 32-bit-pgoff_t architectures.  And that assumes that the architecture packs
 * the type/offset into the pte as 5/27 as well.
 */
#define MAX_SWAPFILES_SHIFT	5

/*
 * 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),	/* blkdev supports 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

#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 */
};

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 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 activate_page(struct page *);
extern void mark_page_accessed(struct page *);
extern void lru_add_drain(void);
extern int lru_add_drain_all(void);
extern void rotate_reclaimable_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);
}

/* LRU Isolation modes. */
#define ISOLATE_INACTIVE 0	/* Isolate inactive pages. */
#define ISOLATE_ACTIVE 1	/* Isolate active pages. */
#define ISOLATE_BOTH 2		/* Isolate both active and inactive pages. */

/* linux/mm/vmscan.c */
extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
					gfp_t gfp_mask, nodemask_t *mask);
extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
						  gfp_t gfp_mask, bool noswap,
						  unsigned int swappiness);
extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
						gfp_t gfp_mask, bool noswap,
						unsigned int swappiness,
						struct zone *zone);
extern int __isolate_lru_page(struct page *page, int mode, int file);
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 scan_mapping_unevictable_pages(struct address_space *);

extern unsigned long scan_unevictable_pages;
extern int scan_unevictable_handler(struct ctl_table *, int,
					void __user *, size_t *, loff_t *);
extern int scan_unevictable_register_node(struct node *node);
extern void scan_unevictable_unregister_node(struct node *node);

extern int kswapd_run(int nid);
extern void kswapd_stop(int nid);

#ifdef CONFIG_MMU
/* linux/mm/shmem.c */
extern int shmem_unuse(swp_entry_t entry, struct page *page);
#endif /* CONFIG_MMU */

#ifdef CONFIG_CGROUP_MEM_RES_CTLR
extern void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
					struct page **pagep, swp_entry_t *ent);
#endif

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 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 int valid_swaphandles(swp_entry_t, unsigned long *);
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 reuse_swap_page(struct page *);
extern int try_to_free_swap(struct page *);
struct backing_dev_info;

#ifdef CONFIG_HIBERNATION
void hibernation_freeze_swap(void);
void hibernation_thaw_swap(void);
swp_entry_t get_swap_for_hibernation(int type);
void swap_free_for_hibernation(swp_entry_t val);
#endif

/* linux/mm/thrash.c */
extern struct mm_struct *swap_token_mm;
extern void grab_swap_token(struct mm_struct *);
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);
}

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

#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)
{
}

#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;
}

/* linux/mm/thrash.c */
static inline void put_swap_token(struct mm_struct *mm)
{
}

static inline void grab_swap_token(struct mm_struct *mm)
{
}

static inline int has_swap_token(struct mm_struct *mm)
{
	return 0;
}

static inline void disable_swap_token(void)
{
}

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

#ifdef CONFIG_CGROUP_MEM_RES_CTLR
static inline int
mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep)
{
	return 0;
}
#endif

#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
1da177e4 LT	12	#include <asm/atomic.h>
	13	#include <asm/page.h>
	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
	22
	23	static inline int current_is_kswapd(void)
	24	{
	25	return current->flags & PF_KSWAPD;
	26	}
	27
	28	/*
	29	* MAX_SWAPFILES defines the maximum number of swaptypes: things which can
	30	* be swapped to. The swap type and the offset into that swap type are
	31	* encoded into pte's and into pgoff_t's in the swapcache. Using five bits
	32	* for the type means that the maximum number of swapcache pages is 27 bits
	33	* on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
	34	* the type/offset into the pte as 5/27 as well.
	35	*/
	36	#define MAX_SWAPFILES_SHIFT 5
a7420aa5 AK	37
	38	/*
	39	* Use some of the swap files numbers for other purposes. This
	40	* is a convenient way to hook into the VM to trigger special
	41	* actions on faults.
	42	*/
	43
	44	/*
	45	* NUMA node memory migration support
	46	*/
	47	#ifdef CONFIG_MIGRATION
	48	#define SWP_MIGRATION_NUM 2
	49	#define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
	50	#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
0697212a	51	#else
a7420aa5	52	#define SWP_MIGRATION_NUM 0
0697212a	53	#endif
1da177e4	54
a7420aa5 AK	55	/*
	56	* Handling of hardware poisoned pages with memory corruption.
	57	*/
	58	#ifdef CONFIG_MEMORY_FAILURE
	59	#define SWP_HWPOISON_NUM 1
	60	#define SWP_HWPOISON MAX_SWAPFILES
	61	#else
	62	#define SWP_HWPOISON_NUM 0
	63	#endif
	64
	65	#define MAX_SWAPFILES \
	66	((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)
	67
1da177e4 LT	68	/*
	69	* Magic header for a swap area. The first part of the union is
	70	* what the swap magic looks like for the old (limited to 128MB)
	71	* swap area format, the second part of the union adds - in the
	72	* old reserved area - some extra information. Note that the first
	73	* kilobyte is reserved for boot loader or disk label stuff...
	74	*
	75	* Having the magic at the end of the PAGE_SIZE makes detecting swap
	76	* areas somewhat tricky on machines that support multiple page sizes.
	77	* For 2.5 we'll probably want to move the magic to just beyond the
	78	* bootbits...
	79	*/
	80	union swap_header {
	81	struct {
	82	char reserved[PAGE_SIZE - 10];
	83	char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
	84	} magic;
	85	struct {
e8f03d02 AD	86	char bootbits[1024]; /* Space for disklabel etc. */
	87	__u32 version;
	88	__u32 last_page;
	89	__u32 nr_badpages;
	90	unsigned char sws_uuid[16];
	91	unsigned char sws_volume[16];
	92	__u32 padding[117];
	93	__u32 badpages[1];
1da177e4 LT	94	} info;
	95	};
	96
	97	/* A swap entry has to fit into a "unsigned long", as
	98	* the entry is hidden in the "index" field of the
	99	* swapper address space.
	100	*/
	101	typedef struct {
	102	unsigned long val;
	103	} swp_entry_t;
	104
	105	/*
	106	* current->reclaim_state points to one of these when a task is running
	107	* memory reclaim
	108	*/
	109	struct reclaim_state {
	110	unsigned long reclaimed_slab;
	111	};
	112
	113	#ifdef __KERNEL__
	114
	115	struct address_space;
	116	struct sysinfo;
	117	struct writeback_control;
	118	struct zone;
	119
	120	/*
	121	* A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
	122	* disk blocks. A list of swap extents maps the entire swapfile. (Where the
	123	* term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
	124	* from setup, they're handled identically.
	125	*
	126	* We always assume that blocks are of size PAGE_SIZE.
	127	*/
	128	struct swap_extent {
	129	struct list_head list;
	130	pgoff_t start_page;
	131	pgoff_t nr_pages;
	132	sector_t start_block;
	133	};
	134
	135	/*
	136	* Max bad pages in the new format..
	137	*/
	138	#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
	139	#define MAX_SWAP_BADPAGES \
	140	((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
	141
	142	enum {
	143	SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
	144	SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
6a6ba831	145	SWP_DISCARDABLE = (1 << 2), /* blkdev supports discard */
7992fde7	146	SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */
20137a49	147	SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
570a335b	148	SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
b2725643	149	SWP_BLKDEV = (1 << 6), /* its a block device */
52b7efdb HD	150	/* add others here before... */
52b7efdb HD	151	SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
1da177e4 LT	152	};
	153
	154	#define SWAP_CLUSTER_MAX 32
748446bb	155	#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
1da177e4	156
570a335b HD	157	#define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */
	158	#define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */
	159	#define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
	160	#define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */
	161	#define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */
aaa46865	162	#define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */
253d553b	163
1da177e4 LT	164	/*
1da177e4 LT	165	* The in-memory structure used to track swap areas.
1da177e4 LT	166	*/
1da177e4 LT	167	struct swap_info_struct {
efa90a98 HD	168	unsigned long flags; /* SWP_USED etc: see above */
	169	signed short prio; /* swap priority of this type */
	170	signed char type; /* strange name for an index */
	171	signed char next; /* next type on the swap list */
7509765a HD	172	unsigned int max; /* extent of the swap_map */
	173	unsigned char swap_map; / vmalloc'ed array of usage counts */
	174	unsigned int lowest_bit; /* index of first free in swap_map */
	175	unsigned int highest_bit; /* index of last free in swap_map */
	176	unsigned int pages; /* total of usable pages of swap */
	177	unsigned int inuse_pages; /* number of those currently in use */
	178	unsigned int cluster_next; /* likely index for next allocation */
	179	unsigned int cluster_nr; /* countdown to next cluster search */
7992fde7 HD	180	unsigned int lowest_alloc; /* while preparing discard cluster */
7992fde7 HD	181	unsigned int highest_alloc; /* while preparing discard cluster */
7509765a HD	182	struct swap_extent *curr_swap_extent;
	183	struct swap_extent first_swap_extent;
	184	struct block_device bdev; / swap device or bdev of swap file */
	185	struct file swap_file; / seldom referenced */
	186	unsigned int old_block_size; /* seldom referenced */
1da177e4 LT	187	};
	188
	189	struct swap_list_t {
	190	int head; /* head of priority-ordered swapfile list */
	191	int next; /* swapfile to be used next */
	192	};
	193
	194	/* Swap 50% full? Release swapcache more aggressively.. */
	195	#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
	196
1da177e4 LT	197	/* linux/mm/page_alloc.c */
1da177e4 LT	198	extern unsigned long totalram_pages;
cb45b0e9	199	extern unsigned long totalreserve_pages;
1da177e4 LT	200	extern unsigned int nr_free_buffer_pages(void);
	201	extern unsigned int nr_free_pagecache_pages(void);
	202
96177299 CL	203	/* Definition of global_page_state not available yet */
	204	#define nr_free_pages() global_page_state(NR_FREE_PAGES)
	205
	206
1da177e4	207	/* linux/mm/swap.c */
f04e9ebb KM	208	extern void __lru_cache_add(struct page *, enum lru_list lru);
f04e9ebb KM	209	extern void lru_cache_add_lru(struct page *, enum lru_list lru);
b3c97528 HH	210	extern void activate_page(struct page *);
b3c97528 HH	211	extern void mark_page_accessed(struct page *);
1da177e4	212	extern void lru_add_drain(void);
053837fc	213	extern int lru_add_drain_all(void);
ac6aadb2	214	extern void rotate_reclaimable_page(struct page *page);
1da177e4 LT	215	extern void swap_setup(void);
1da177e4 LT	216
894bc310 LS	217	extern void add_page_to_unevictable_list(struct page *page);
894bc310 LS	218
f04e9ebb KM	219	/**
	220	* lru_cache_add: add a page to the page lists
	221	* @page: the page to add
	222	*/
4f98a2fe	223	static inline void lru_cache_add_anon(struct page *page)
f04e9ebb	224	{
4f98a2fe	225	__lru_cache_add(page, LRU_INACTIVE_ANON);
f04e9ebb KM	226	}
f04e9ebb KM	227
4f98a2fe RR	228	static inline void lru_cache_add_file(struct page *page)
	229	{
	230	__lru_cache_add(page, LRU_INACTIVE_FILE);
	231	}
	232
c175a0ce MG	233	/* LRU Isolation modes. */
	234	#define ISOLATE_INACTIVE 0 /* Isolate inactive pages. */
	235	#define ISOLATE_ACTIVE 1 /* Isolate active pages. */
	236	#define ISOLATE_BOTH 2 /* Isolate both active and inactive pages. */
	237
1da177e4	238	/* linux/mm/vmscan.c */
dac1d27b	239	extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
327c0e96	240	gfp_t gfp_mask, nodemask_t *mask);
e1a1cd59	241	extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
a7885eb8 KM	242	gfp_t gfp_mask, bool noswap,
a7885eb8 KM	243	unsigned int swappiness);
4e416953 BS	244	extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
	245	gfp_t gfp_mask, bool noswap,
	246	unsigned int swappiness,
14fec796	247	struct zone *zone);
4f98a2fe	248	extern int __isolate_lru_page(struct page *page, int mode, int file);
69e05944	249	extern unsigned long shrink_all_memory(unsigned long nr_pages);
1da177e4	250	extern int vm_swappiness;
b20a3503	251	extern int remove_mapping(struct address_space mapping, struct page page);
bd1e22b8	252	extern long vm_total_pages;
b20a3503	253
9eeff239 CL	254	#ifdef CONFIG_NUMA
9eeff239 CL	255	extern int zone_reclaim_mode;
9614634f	256	extern int sysctl_min_unmapped_ratio;
0ff38490	257	extern int sysctl_min_slab_ratio;
9eeff239 CL	258	extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
	259	#else
	260	#define zone_reclaim_mode 0
	261	static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
	262	{
	263	return 0;
	264	}
	265	#endif
	266
894bc310	267	extern int page_evictable(struct page page, struct vm_area_struct vma);
89e004ea	268	extern void scan_mapping_unevictable_pages(struct address_space *);
af936a16 LS	269
af936a16 LS	270	extern unsigned long scan_unevictable_pages;
8d65af78	271	extern int scan_unevictable_handler(struct ctl_table *, int,
af936a16 LS	272	void __user , size_t , loff_t *);
	273	extern int scan_unevictable_register_node(struct node *node);
	274	extern void scan_unevictable_unregister_node(struct node *node);
894bc310	275
3218ae14	276	extern int kswapd_run(int nid);
8fe23e05	277	extern void kswapd_stop(int nid);
3218ae14	278
1da177e4 LT	279	#ifdef CONFIG_MMU
	280	/* linux/mm/shmem.c */
	281	extern int shmem_unuse(swp_entry_t entry, struct page *page);
	282	#endif /* CONFIG_MMU */
	283
87946a72 DN	284	#ifdef CONFIG_CGROUP_MEM_RES_CTLR
	285	extern void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
	286	struct page *pagep, swp_entry_t ent);
	287	#endif
	288
1da177e4 LT	289	extern void swap_unplug_io_fn(struct backing_dev_info , struct page );
	290
	291	#ifdef CONFIG_SWAP
	292	/* linux/mm/page_io.c */
aca8bf32	293	extern int swap_readpage(struct page *);
1da177e4	294	extern int swap_writepage(struct page page, struct writeback_control wbc);
6712ecf8	295	extern void end_swap_bio_read(struct bio *bio, int err);
1da177e4 LT	296
	297	/* linux/mm/swap_state.c */
	298	extern struct address_space swapper_space;
	299	#define total_swapcache_pages swapper_space.nrpages
	300	extern void show_swap_cache_info(void);
ac47b003	301	extern int add_to_swap(struct page *);
73b1262f	302	extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
1da177e4 LT	303	extern void __delete_from_swap_cache(struct page *);
1da177e4 LT	304	extern void delete_from_swap_cache(struct page *);
1da177e4 LT	305	extern void free_page_and_swap_cache(struct page *);
1da177e4 LT	306	extern void free_pages_and_swap_cache(struct page **, int);
46017e95	307	extern struct page *lookup_swap_cache(swp_entry_t);
02098fea	308	extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
46017e95	309	struct vm_area_struct *vma, unsigned long addr);
02098fea	310	extern struct page *swapin_readahead(swp_entry_t, gfp_t,
46017e95 HD	311	struct vm_area_struct *vma, unsigned long addr);
46017e95 HD	312
1da177e4	313	/* linux/mm/swapfile.c */
b962716b	314	extern long nr_swap_pages;
1da177e4	315	extern long total_swap_pages;
1da177e4 LT	316	extern void si_swapinfo(struct sysinfo *);
1da177e4 LT	317	extern swp_entry_t get_swap_page(void);
1da177e4	318	extern int valid_swaphandles(swp_entry_t, unsigned long *);
570a335b	319	extern int add_swap_count_continuation(swp_entry_t, gfp_t);
aaa46865	320	extern void swap_shmem_alloc(swp_entry_t);
570a335b HD	321	extern int swap_duplicate(swp_entry_t);
570a335b HD	322	extern int swapcache_prepare(swp_entry_t);
1da177e4	323	extern void swap_free(swp_entry_t);
cb4b86ba	324	extern void swapcache_free(swp_entry_t, struct page *page);
2509ef26	325	extern int free_swap_and_cache(swp_entry_t);
7bf23687	326	extern int swap_type_of(dev_t, sector_t, struct block_device **);
f577eb30	327	extern unsigned int count_swap_pages(int, int);
d4906e1a	328	extern sector_t map_swap_page(struct page , struct block_device *);
3aef83e0	329	extern sector_t swapdev_block(int, pgoff_t);
7b1fe597	330	extern int reuse_swap_page(struct page *);
a2c43eed	331	extern int try_to_free_swap(struct page *);
1da177e4 LT	332	struct backing_dev_info;
1da177e4 LT	333
d2997b10 KH	334	#ifdef CONFIG_HIBERNATION
	335	void hibernation_freeze_swap(void);
	336	void hibernation_thaw_swap(void);
	337	swp_entry_t get_swap_for_hibernation(int type);
	338	void swap_free_for_hibernation(swp_entry_t val);
	339	#endif
	340
1da177e4	341	/* linux/mm/thrash.c */
a5c9b696 HD	342	extern struct mm_struct *swap_token_mm;
a5c9b696 HD	343	extern void grab_swap_token(struct mm_struct *);
1da177e4 LT	344	extern void __put_swap_token(struct mm_struct *);
	345
	346	static inline int has_swap_token(struct mm_struct *mm)
	347	{
	348	return (mm == swap_token_mm);
	349	}
	350
	351	static inline void put_swap_token(struct mm_struct *mm)
	352	{
	353	if (has_swap_token(mm))
	354	__put_swap_token(mm);
	355	}
	356
f7b7fd8f RR	357	static inline void disable_swap_token(void)
	358	{
	359	put_swap_token(swap_token_mm);
	360	}
	361
d13d1443	362	#ifdef CONFIG_CGROUP_MEM_RES_CTLR
8a9478ca KH	363	extern void
8a9478ca KH	364	mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout);
02491447	365	extern int mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep);
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
	372	#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
	373	extern void mem_cgroup_uncharge_swap(swp_entry_t ent);
	374	#else
	375	static inline void mem_cgroup_uncharge_swap(swp_entry_t ent)
d13d1443 KH	376	{
	377	}
	378	#endif
	379
1da177e4 LT	380	#else /* CONFIG_SWAP */
1da177e4 LT	381
b962716b HD	382	#define nr_swap_pages 0L
b962716b HD	383	#define total_swap_pages 0L
1da177e4 LT	384	#define total_swapcache_pages 0UL
	385
	386	#define si_swapinfo(val) \
	387	do { (val)->freeswap = (val)->totalswap = 0; } while (0)
9ae5b3c7 OH	388	/* only sparc can not include linux/pagemap.h in this file
9ae5b3c7 OH	389	* so leave page_cache_release and release_pages undeclared... */
1da177e4 LT	390	#define free_page_and_swap_cache(page) \
	391	page_cache_release(page)
	392	#define free_pages_and_swap_cache(pages, nr) \
	393	release_pages((pages), (nr), 0);
	394
bd96b9eb CK	395	static inline void show_swap_cache_info(void)
	396	{
	397	}
	398
2509ef26	399	#define free_swap_and_cache(swp) is_migration_entry(swp)
cb4b86ba	400	#define swapcache_prepare(swp) is_migration_entry(swp)
bd96b9eb	401
570a335b	402	static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
355cfa73	403	{
570a335b HD	404	return 0;
	405	}
	406
aaa46865 HD	407	static inline void swap_shmem_alloc(swp_entry_t swp)
	408	{
	409	}
	410
570a335b HD	411	static inline int swap_duplicate(swp_entry_t swp)
	412	{
	413	return 0;
355cfa73 KH	414	}
355cfa73 KH	415
bd96b9eb CK	416	static inline void swap_free(swp_entry_t swp)
	417	{
	418	}
	419
cb4b86ba KH	420	static inline void swapcache_free(swp_entry_t swp, struct page *page)
	421	{
	422	}
	423
02098fea	424	static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
bd96b9eb CK	425	struct vm_area_struct *vma, unsigned long addr)
	426	{
	427	return NULL;
	428	}
	429
9fab5619 HD	430	static inline int swap_writepage(struct page p, struct writeback_control wbc)
	431	{
	432	return 0;
	433	}
	434
bd96b9eb CK	435	static inline struct page *lookup_swap_cache(swp_entry_t swp)
	436	{
	437	return NULL;
	438	}
	439
60371d97 HD	440	static inline int add_to_swap(struct page *page)
	441	{
	442	return 0;
	443	}
	444
73b1262f HD	445	static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
73b1262f HD	446	gfp_t gfp_mask)
bd96b9eb	447	{
73b1262f	448	return -1;
bd96b9eb CK	449	}
	450
	451	static inline void __delete_from_swap_cache(struct page *page)
	452	{
	453	}
	454
	455	static inline void delete_from_swap_cache(struct page *page)
	456	{
	457	}
	458
7b1fe597	459	#define reuse_swap_page(page) (page_mapcount(page) == 1)
1da177e4	460
a2c43eed	461	static inline int try_to_free_swap(struct page *page)
68a22394 RR	462	{
	463	return 0;
	464	}
	465
1da177e4 LT	466	static inline swp_entry_t get_swap_page(void)
	467	{
	468	swp_entry_t entry;
	469	entry.val = 0;
	470	return entry;
	471	}
	472
	473	/* linux/mm/thrash.c */
a5abeeac JW	474	static inline void put_swap_token(struct mm_struct *mm)
	475	{
	476	}
	477
	478	static inline void grab_swap_token(struct mm_struct *mm)
	479	{
	480	}
	481
	482	static inline int has_swap_token(struct mm_struct *mm)
	483	{
	484	return 0;
	485	}
	486
	487	static inline void disable_swap_token(void)
	488	{
	489	}
1da177e4	490
e767e056 DN	491	static inline void
	492	mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
	493	{
	494	}
	495
02491447 DN	496	#ifdef CONFIG_CGROUP_MEM_RES_CTLR
	497	static inline int
	498	mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep)
	499	{
	500	return 0;
	501	}
	502	#endif
	503
1da177e4 LT	504	#endif /* CONFIG_SWAP */
	505	#endif /* __KERNEL__*/
	506	#endif /* _LINUX_SWAP_H */