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#ifndef _LINUX_SWAP_H

#define _LINUX_SWAP_H

#include <linux/spinlock.h>

#include <linux/linkage.h>

#include <linux/mmzone.h>

#include <linux/list.h>

#include <linux/sched.h>

#include <asm/atomic.h>

#include <asm/page.h>

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

#ifndef CONFIG_MIGRATION

#define MAX_SWAPFILES           (1 << MAX_SWAPFILES_SHIFT)

#else

/* Use last two entries for page migration swap entries */

#define MAX_SWAPFILES           ((1 << MAX_SWAPFILES_SHIFT)-2)

#define SWP_MIGRATION_READ      MAX_SWAPFILES

#define SWP_MIGRATION_WRITE     (MAX_SWAPFILES + 1)

#endif

/*

 * Magic header for a swap area. The first part of the union is

 * what the swap magic looks like for the old (limited to 128MB)

 * swap area format, the second part of the union adds - in the

 * old reserved area - some extra information. Note that the first

 * kilobyte is reserved for boot loader or disk label stuff...

 *

 * Having the magic at the end of the PAGE_SIZE makes detecting swap

 * areas somewhat tricky on machines that support multiple page sizes.

 * For 2.5 we'll probably want to move the magic to just beyond the

 * bootbits...

 */

union swap_header {

        struct {

                char reserved[PAGE_SIZE - 10];

                char magic[10];                 /* SWAP-SPACE or SWAPSPACE2 */

        } magic;

        struct {

                char            bootbits[1024]; /* Space for disklabel etc. */

                __u32           version;

                __u32           last_page;

                __u32           nr_badpages;

                unsigned char   sws_uuid[16];

                unsigned char   sws_volume[16];

                __u32           padding[117];

                __u32           badpages[1];

        } info;

};

 /* A swap entry has to fit into a "unsigned long", as

  * the entry is hidden in the "index" field of the

  * swapper address space.

  */

typedef struct {

        unsigned long val;

} swp_entry_t;

/*

 * current->reclaim_state points to one of these when a task is running

 * memory reclaim

 */

struct reclaim_state {

        unsigned long reclaimed_slab;

};

#ifdef __KERNEL__

struct address_space;

struct sysinfo;

struct writeback_control;

struct zone;

/*

 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of

 * disk blocks.  A list of swap extents maps the entire swapfile.  (Where the

 * term `swapfile' refers to either a blockdevice or an IS_REG file.  Apart

 * from setup, they're handled identically.

 *

 * We always assume that blocks are of size PAGE_SIZE.

 */

struct swap_extent {

        struct list_head list;

        pgoff_t start_page;

        pgoff_t nr_pages;

        sector_t start_block;

};

/*

 * Max bad pages in the new format..

 */

#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)

#define MAX_SWAP_BADPAGES \

        ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))

enum {

        SWP_USED        = (1 << 0),      /* is slot in swap_info[] used? */

        SWP_WRITEOK     = (1 << 1),     /* ok to write to this swap?    */

        SWP_ACTIVE      = (SWP_USED | SWP_WRITEOK),

                                        /* add others here before... */

        SWP_SCANNING    = (1 << 8),     /* refcount in scan_swap_map */

};

#define SWAP_CLUSTER_MAX 32

#define SWAP_MAP_MAX    0x7fff

#define SWAP_MAP_BAD    0x8000

/*

 * The in-memory structure used to track swap areas.

 */

struct swap_info_struct {

        unsigned int flags;

        int prio;                       /* swap priority */

        struct file *swap_file;

        struct block_device *bdev;

        struct list_head extent_list;

        struct swap_extent *curr_swap_extent;

        unsigned old_block_size;

        unsigned short * swap_map;

        unsigned int lowest_bit;

        unsigned int highest_bit;

        unsigned int cluster_next;

        unsigned int cluster_nr;

        unsigned int pages;

        unsigned int max;

        unsigned int inuse_pages;

        int next;                       /* next entry on swap list */

};

struct swap_list_t {

        int head;       /* head of priority-ordered swapfile list */

        int next;       /* swapfile to be used next */

};

/* Swap 50% full? Release swapcache more aggressively.. */

#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)

/* linux/mm/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 totalreserve_pages;

extern long nr_swap_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 FASTCALL(lru_cache_add(struct page *));

extern void FASTCALL(lru_cache_add_active(struct page *));

extern void FASTCALL(activate_page(struct page *));

extern void FASTCALL(mark_page_accessed(struct page *));

extern void lru_add_drain(void);

extern int lru_add_drain_all(void);

extern int rotate_reclaimable_page(struct page *page);

extern void swap_setup(void);

/* linux/mm/vmscan.c */

extern unsigned long try_to_free_pages(struct zone **zones, int order,

                                        gfp_t gfp_mask);

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 kswapd_run(int nid);

#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 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 *, gfp_t);

extern void __delete_from_swap_cache(struct page *);

extern void delete_from_swap_cache(struct page *);

extern int move_to_swap_cache(struct page *, swp_entry_t);

extern int move_from_swap_cache(struct page *, unsigned long,

                struct address_space *);

extern void free_page_and_swap_cache(struct page *);

extern void free_pages_and_swap_cache(struct page **, int);

extern struct page * lookup_swap_cache(swp_entry_t);

extern struct page * read_swap_cache_async(swp_entry_t, struct vm_area_struct *vma,

                                           unsigned long addr);

/* linux/mm/swapfile.c */

extern long total_swap_pages;

extern unsigned int nr_swapfiles;

extern void si_swapinfo(struct sysinfo *);

extern swp_entry_t get_swap_page(void);

extern swp_entry_t get_swap_page_of_type(int);

extern int swap_duplicate(swp_entry_t);

extern int valid_swaphandles(swp_entry_t, unsigned long *);

extern void swap_free(swp_entry_t);

extern void free_swap_and_cache(swp_entry_t);

extern int swap_type_of(dev_t, sector_t, struct block_device **);

extern unsigned int count_swap_pages(int, int);

extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);

extern sector_t swapdev_block(int, pgoff_t);

extern struct swap_info_struct *get_swap_info_struct(unsigned);

extern int can_share_swap_page(struct page *);

extern int remove_exclusive_swap_page(struct page *);

struct backing_dev_info;

extern spinlock_t swap_lock;

/* linux/mm/thrash.c */

extern struct mm_struct * swap_token_mm;

extern void grab_swap_token(void);

extern void __put_swap_token(struct mm_struct *);

static inline int has_swap_token(struct mm_struct *mm)

{

        return (mm == swap_token_mm);

}

static inline void put_swap_token(struct mm_struct *mm)

{

        if (has_swap_token(mm))

                __put_swap_token(mm);

}

static inline void disable_swap_token(void)

{

        put_swap_token(swap_token_mm);

}

#else /* CONFIG_SWAP */

#define total_swap_pages                        0

#define total_swapcache_pages                   0UL

#define si_swapinfo(val) \

        do { (val)->freeswap = (val)->totalswap = 0; } while (0)

/* only sparc can not include linux/pagemap.h in this file

 * so leave page_cache_release and release_pages undeclared... */

#define free_page_and_swap_cache(page) \

        page_cache_release(page)

#define free_pages_and_swap_cache(pages, nr) \

        release_pages((pages), (nr), 0);

static inline void show_swap_cache_info(void)

{

}

static inline void free_swap_and_cache(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 struct page *read_swap_cache_async(swp_entry_t swp,

                        struct vm_area_struct *vma, unsigned long addr)

{

        return NULL;

}

static inline struct page *lookup_swap_cache(swp_entry_t swp)

{

        return NULL;

}

static inline int valid_swaphandles(swp_entry_t entry, unsigned long *offset)

{

        return 0;

}

#define can_share_swap_page(p)                  (page_mapcount(p) == 1)

static inline int move_to_swap_cache(struct page *page, swp_entry_t entry)

{

        return 1;

}

static inline int move_from_swap_cache(struct page *page, unsigned long index,

                                        struct address_space *mapping)

{

        return 1;

}

static inline void __delete_from_swap_cache(struct page *page)

{

}

static inline void delete_from_swap_cache(struct page *page)

{

}

#define swap_token_default_timeout              0

static inline int remove_exclusive_swap_page(struct page *p)

{

        return 0;

}

static inline swp_entry_t get_swap_page(void)

{

        swp_entry_t entry;

        entry.val = 0;

        return entry;

}

/* linux/mm/thrash.c */

#define put_swap_token(x) do { } while(0)

#define grab_swap_token()  do { } while(0)

#define has_swap_token(x) 0

#define disable_swap_token() do { } while(0)

#endif /* CONFIG_SWAP */

#endif /* __KERNEL__*/

#endif /* _LINUX_SWAP_H */