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#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 pte_chain;

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(void);

/* linux/mm/memory.c */

extern void swapin_readahead(swp_entry_t);

/* linux/mm/page_alloc.c */

extern unsigned long totalram_pages;

extern unsigned long totalhigh_pages;

extern int nr_swap_pages;       /* XXX: shouldn't this be ulong? --hch */

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, unsigned int);

extern int shrink_all_memory(int);

extern int vm_swappiness;

/* linux/mm/rmap.c */

#ifdef CONFIG_MMU

int FASTCALL(page_referenced(struct page *));

struct pte_chain *FASTCALL(page_add_rmap(struct page *, pte_t *,

                                        struct pte_chain *));

void FASTCALL(page_remove_rmap(struct page *, pte_t *));

int FASTCALL(try_to_unmap(struct page *));

/* linux/mm/shmem.c */

extern int shmem_unuse(swp_entry_t entry, struct page *page);

#else

#define page_referenced(page)   TestClearPageReferenced(page)

#define try_to_unmap(page)      SWAP_FAIL

#endif /* CONFIG_MMU */

/* return values of try_to_unmap */

#define SWAP_SUCCESS    0

#define SWAP_AGAIN      1

#define SWAP_FAIL       2

#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);

/* linux/mm/swapfile.c */

extern int 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 *);

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)

#else /* CONFIG_SWAP */

#define total_swap_pages                        0

#define total_swapcache_pages                   0UL

#define si_swapinfo(val) \

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

#define free_page_and_swap_cache(page) \

        page_cache_release(page)

#define free_pages_and_swap_cache(pages, nr) \

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

#define show_swap_cache_info()                  /*NOTHING*/

#define free_swap_and_cache(swp)                /*NOTHING*/

#define swap_duplicate(swp)                     /*NOTHING*/

#define swap_free(swp)                          /*NOTHING*/

#define read_swap_cache_async(swp)              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*/

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;

}

#endif /* CONFIG_SWAP */

#endif /* __KERNEL__*/

#endif /* _LINUX_SWAP_H */