295 lines
8.8 KiB
C
295 lines
8.8 KiB
C
#ifndef _LINUX_SWAP_H
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#define _LINUX_SWAP_H
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#include <linux/config.h>
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#include <linux/spinlock.h>
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#include <linux/linkage.h>
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#include <linux/mmzone.h>
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#include <linux/list.h>
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#include <linux/sched.h>
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#include <asm/atomic.h>
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#include <asm/page.h>
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#define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
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#define SWAP_FLAG_PRIO_MASK 0x7fff
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#define SWAP_FLAG_PRIO_SHIFT 0
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static inline int current_is_kswapd(void)
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{
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return current->flags & PF_KSWAPD;
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}
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/*
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* MAX_SWAPFILES defines the maximum number of swaptypes: things which can
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* be swapped to. The swap type and the offset into that swap type are
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* encoded into pte's and into pgoff_t's in the swapcache. Using five bits
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* for the type means that the maximum number of swapcache pages is 27 bits
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* on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
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* the type/offset into the pte as 5/27 as well.
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*/
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#define MAX_SWAPFILES_SHIFT 5
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#define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
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/*
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* Magic header for a swap area. The first part of the union is
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* what the swap magic looks like for the old (limited to 128MB)
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* swap area format, the second part of the union adds - in the
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* old reserved area - some extra information. Note that the first
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* kilobyte is reserved for boot loader or disk label stuff...
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*
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* Having the magic at the end of the PAGE_SIZE makes detecting swap
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* areas somewhat tricky on machines that support multiple page sizes.
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* For 2.5 we'll probably want to move the magic to just beyond the
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* bootbits...
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*/
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union swap_header {
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struct {
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char reserved[PAGE_SIZE - 10];
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char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
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} magic;
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struct {
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char bootbits[1024]; /* Space for disklabel etc. */
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unsigned int version;
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unsigned int last_page;
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unsigned int nr_badpages;
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unsigned int padding[125];
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unsigned int badpages[1];
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} info;
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};
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/* A swap entry has to fit into a "unsigned long", as
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* the entry is hidden in the "index" field of the
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* swapper address space.
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*/
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typedef struct {
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unsigned long val;
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} swp_entry_t;
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/*
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* current->reclaim_state points to one of these when a task is running
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* memory reclaim
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*/
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struct reclaim_state {
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unsigned long reclaimed_slab;
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};
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#ifdef __KERNEL__
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struct address_space;
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struct sysinfo;
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struct writeback_control;
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struct zone;
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/*
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* A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
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* disk blocks. A list of swap extents maps the entire swapfile. (Where the
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* term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
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* from setup, they're handled identically.
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*
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* We always assume that blocks are of size PAGE_SIZE.
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*/
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struct swap_extent {
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struct list_head list;
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pgoff_t start_page;
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pgoff_t nr_pages;
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sector_t start_block;
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};
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/*
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* Max bad pages in the new format..
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*/
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#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
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#define MAX_SWAP_BADPAGES \
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((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
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enum {
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SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
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SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
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SWP_ACTIVE = (SWP_USED | SWP_WRITEOK),
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};
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#define SWAP_CLUSTER_MAX 32
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#define SWAP_MAP_MAX 0x7fff
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#define SWAP_MAP_BAD 0x8000
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/*
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* The in-memory structure used to track swap areas.
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* extent_list.prev points at the lowest-index extent. That list is
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* sorted.
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*/
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struct swap_info_struct {
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unsigned int flags;
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spinlock_t sdev_lock;
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struct file *swap_file;
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struct block_device *bdev;
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struct list_head extent_list;
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int nr_extents;
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struct swap_extent *curr_swap_extent;
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unsigned old_block_size;
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unsigned short * swap_map;
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unsigned int lowest_bit;
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unsigned int highest_bit;
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unsigned int cluster_next;
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unsigned int cluster_nr;
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int prio; /* swap priority */
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int pages;
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unsigned long max;
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unsigned long inuse_pages;
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int next; /* next entry on swap list */
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};
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struct swap_list_t {
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int head; /* head of priority-ordered swapfile list */
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int next; /* swapfile to be used next */
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};
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/* Swap 50% full? Release swapcache more aggressively.. */
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#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
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/* linux/mm/oom_kill.c */
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extern void out_of_memory(unsigned int __nocast gfp_mask, int order);
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/* linux/mm/memory.c */
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extern void swapin_readahead(swp_entry_t, unsigned long, struct vm_area_struct *);
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/* linux/mm/page_alloc.c */
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extern unsigned long totalram_pages;
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extern unsigned long totalhigh_pages;
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extern long nr_swap_pages;
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extern unsigned int nr_free_pages(void);
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extern unsigned int nr_free_pages_pgdat(pg_data_t *pgdat);
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extern unsigned int nr_free_buffer_pages(void);
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extern unsigned int nr_free_pagecache_pages(void);
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/* linux/mm/swap.c */
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extern void FASTCALL(lru_cache_add(struct page *));
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extern void FASTCALL(lru_cache_add_active(struct page *));
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extern void FASTCALL(activate_page(struct page *));
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extern void FASTCALL(mark_page_accessed(struct page *));
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extern void lru_add_drain(void);
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extern int rotate_reclaimable_page(struct page *page);
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extern void swap_setup(void);
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/* linux/mm/vmscan.c */
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extern int try_to_free_pages(struct zone **, unsigned int);
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extern int zone_reclaim(struct zone *, unsigned int, unsigned int);
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extern int shrink_all_memory(int);
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extern int vm_swappiness;
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#ifdef CONFIG_MMU
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/* linux/mm/shmem.c */
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extern int shmem_unuse(swp_entry_t entry, struct page *page);
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#endif /* CONFIG_MMU */
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extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);
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#ifdef CONFIG_SWAP
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/* linux/mm/page_io.c */
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extern int swap_readpage(struct file *, struct page *);
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extern int swap_writepage(struct page *page, struct writeback_control *wbc);
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extern int rw_swap_page_sync(int, swp_entry_t, struct page *);
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/* linux/mm/swap_state.c */
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extern struct address_space swapper_space;
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#define total_swapcache_pages swapper_space.nrpages
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extern void show_swap_cache_info(void);
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extern int add_to_swap(struct page *);
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extern void __delete_from_swap_cache(struct page *);
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extern void delete_from_swap_cache(struct page *);
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extern int move_to_swap_cache(struct page *, swp_entry_t);
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extern int move_from_swap_cache(struct page *, unsigned long,
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struct address_space *);
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extern void free_page_and_swap_cache(struct page *);
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extern void free_pages_and_swap_cache(struct page **, int);
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extern struct page * lookup_swap_cache(swp_entry_t);
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extern struct page * read_swap_cache_async(swp_entry_t, struct vm_area_struct *vma,
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unsigned long addr);
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/* linux/mm/swapfile.c */
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extern long total_swap_pages;
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extern unsigned int nr_swapfiles;
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extern struct swap_info_struct swap_info[];
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extern void si_swapinfo(struct sysinfo *);
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extern swp_entry_t get_swap_page(void);
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extern int swap_duplicate(swp_entry_t);
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extern int valid_swaphandles(swp_entry_t, unsigned long *);
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extern void swap_free(swp_entry_t);
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extern void free_swap_and_cache(swp_entry_t);
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extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
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extern struct swap_info_struct *get_swap_info_struct(unsigned);
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extern int can_share_swap_page(struct page *);
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extern int remove_exclusive_swap_page(struct page *);
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struct backing_dev_info;
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extern struct swap_list_t swap_list;
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extern spinlock_t swaplock;
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#define swap_list_lock() spin_lock(&swaplock)
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#define swap_list_unlock() spin_unlock(&swaplock)
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#define swap_device_lock(p) spin_lock(&p->sdev_lock)
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#define swap_device_unlock(p) spin_unlock(&p->sdev_lock)
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/* linux/mm/thrash.c */
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extern struct mm_struct * swap_token_mm;
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extern unsigned long swap_token_default_timeout;
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extern void grab_swap_token(void);
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extern void __put_swap_token(struct mm_struct *);
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static inline int has_swap_token(struct mm_struct *mm)
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{
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return (mm == swap_token_mm);
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}
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static inline void put_swap_token(struct mm_struct *mm)
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{
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if (has_swap_token(mm))
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__put_swap_token(mm);
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}
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#else /* CONFIG_SWAP */
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#define total_swap_pages 0
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#define total_swapcache_pages 0UL
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#define si_swapinfo(val) \
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do { (val)->freeswap = (val)->totalswap = 0; } while (0)
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#define free_page_and_swap_cache(page) \
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page_cache_release(page)
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#define free_pages_and_swap_cache(pages, nr) \
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release_pages((pages), (nr), 0);
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#define show_swap_cache_info() /*NOTHING*/
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#define free_swap_and_cache(swp) /*NOTHING*/
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#define swap_duplicate(swp) /*NOTHING*/
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#define swap_free(swp) /*NOTHING*/
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#define read_swap_cache_async(swp,vma,addr) NULL
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#define lookup_swap_cache(swp) NULL
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#define valid_swaphandles(swp, off) 0
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#define can_share_swap_page(p) 0
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#define move_to_swap_cache(p, swp) 1
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#define move_from_swap_cache(p, i, m) 1
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#define __delete_from_swap_cache(p) /*NOTHING*/
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#define delete_from_swap_cache(p) /*NOTHING*/
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#define swap_token_default_timeout 0
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static inline int remove_exclusive_swap_page(struct page *p)
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{
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return 0;
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}
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static inline swp_entry_t get_swap_page(void)
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{
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swp_entry_t entry;
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entry.val = 0;
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return entry;
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}
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/* linux/mm/thrash.c */
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#define put_swap_token(x) do { } while(0)
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#define grab_swap_token() do { } while(0)
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#define has_swap_token(x) 0
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#endif /* CONFIG_SWAP */
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#endif /* __KERNEL__*/
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#endif /* _LINUX_SWAP_H */
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