#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 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/oom_kill.c */ extern void out_of_memory(unsigned int __nocast gfp_mask, int order); /* 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 totalhigh_pages; extern long nr_swap_pages; 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); extern int zone_reclaim(struct zone *, unsigned int, unsigned int); extern int shrink_all_memory(int); extern int vm_swappiness; #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 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, struct vm_area_struct *vma, unsigned long addr); /* linux/mm/swapfile.c */ extern long 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 *); struct backing_dev_info; extern spinlock_t swap_lock; /* linux/mm/thrash.c */ extern struct mm_struct * swap_token_mm; extern unsigned long swap_token_default_timeout; 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); } #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); #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,vma,addr) 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*/ #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 #endif /* CONFIG_SWAP */ #endif /* __KERNEL__*/ #endif /* _LINUX_SWAP_H */