blob: 62d81435347a7e2a7fa212fd9ae2b17e3e43224c [file] [log] [blame]
#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
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.
/* Use last two entries for page migration swap entries */
* 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)
((__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 */
/* add others here before... */
SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
#define SWAP_MAP_MAX 0x7fff
#define SWAP_MAP_BAD 0x8000
* The in-memory structure used to track swap areas.
struct swap_info_struct {
unsigned long flags;
int prio; /* swap priority */
int next; /* next entry on swap list */
struct file *swap_file;
struct block_device *bdev;
struct list_head extent_list;
struct swap_extent *curr_swap_extent;
unsigned short *swap_map;
unsigned int lowest_bit;
unsigned int highest_bit;
unsigned int lowest_alloc; /* while preparing discard cluster */
unsigned int highest_alloc; /* while preparing discard cluster */
unsigned int cluster_next;
unsigned int cluster_nr;
unsigned int pages;
unsigned int max;
unsigned int inuse_pages;
unsigned int old_block_size;
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_active_anon(struct page *page)
__lru_cache_add(page, LRU_ACTIVE_ANON);
static inline void lru_cache_add_file(struct page *page)
__lru_cache_add(page, LRU_INACTIVE_FILE);
static inline void lru_cache_add_active_file(struct page *page)
__lru_cache_add(page, LRU_ACTIVE_FILE);
/* 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 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;
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);
#define zone_reclaim_mode 0
static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
return 0;
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, struct file *,
void __user *, size_t *, loff_t *);
extern int scan_unevictable_register_node(struct node *node);
extern void scan_unevictable_unregister_node(struct node *node);
static inline int page_evictable(struct page *page,
struct vm_area_struct *vma)
return 1;
static inline void scan_mapping_unevictable_pages(struct address_space *mapping)
static inline int scan_unevictable_register_node(struct node *node)
return 0;
static inline void scan_unevictable_unregister_node(struct node *node) { }
extern int kswapd_run(int nid);
/* 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 *);
/* 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 *);
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 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 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 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 reuse_swap_page(struct page *);
extern int try_to_free_swap(struct page *);
struct backing_dev_info;
/* 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))
static inline void disable_swap_token(void)
extern void mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent);
static inline void
mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
extern void mem_cgroup_uncharge_swap(swp_entry_t ent);
static inline void mem_cgroup_uncharge_swap(swp_entry_t ent)
#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) \
#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 swap_duplicate(swp) is_migration_entry(swp)
static inline void swap_free(swp_entry_t swp)
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 */
#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)
static inline int mem_cgroup_cache_charge_swapin(struct page *page,
struct mm_struct *mm, gfp_t mask, bool locked)
return 0;
#endif /* CONFIG_SWAP */
#endif /* __KERNEL__*/
#endif /* _LINUX_SWAP_H */