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Diffstat (limited to 'include/linux/swap.h')
| -rw-r--r-- | include/linux/swap.h | 508 |
1 files changed, 508 insertions, 0 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h new file mode 100644 index 00000000..a273468f --- /dev/null +++ b/include/linux/swap.h @@ -0,0 +1,508 @@ +#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 +#define SWAP_FLAG_PRIO_SHIFT 0 +#define SWAP_FLAG_DISCARD 0x10000 /* discard swap cluster after use */ + +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 + +/* + * Use some of the swap files numbers for other purposes. This + * is a convenient way to hook into the VM to trigger special + * actions on faults. + */ + +/* + * NUMA node memory migration support + */ +#ifdef CONFIG_MIGRATION +#define SWP_MIGRATION_NUM 2 +#define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM) +#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1) +#else +#define SWP_MIGRATION_NUM 0 +#endif + +/* + * Handling of hardware poisoned pages with memory corruption. + */ +#ifdef CONFIG_MEMORY_FAILURE +#define SWP_HWPOISON_NUM 1 +#define SWP_HWPOISON MAX_SWAPFILES +#else +#define SWP_HWPOISON_NUM 0 +#endif + +#define MAX_SWAPFILES \ + ((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM) + +/* + * 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_DISCARDABLE = (1 << 2), /* swapon+blkdev support discard */ + SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */ + SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */ + SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */ + SWP_BLKDEV = (1 << 6), /* its a block device */ + /* add others here before... */ + SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */ +}; + +#define SWAP_CLUSTER_MAX 32 +#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX + +/* + * Ratio between the present memory in the zone and the "gap" that + * we're allowing kswapd to shrink in addition to the per-zone high + * wmark, even for zones that already have the high wmark satisfied, + * in order to provide better per-zone lru behavior. We are ok to + * spend not more than 1% of the memory for this zone balancing "gap". + */ +#define KSWAPD_ZONE_BALANCE_GAP_RATIO 100 + +#define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */ +#define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */ +#define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */ +#define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */ +#define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */ +#define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */ + +/* + * The in-memory structure used to track swap areas. + */ +struct swap_info_struct { + unsigned long flags; /* SWP_USED etc: see above */ + signed short prio; /* swap priority of this type */ + signed char type; /* strange name for an index */ + signed char next; /* next type on the swap list */ + unsigned int max; /* extent of the swap_map */ + unsigned char *swap_map; /* vmalloc'ed array of usage counts */ + unsigned int lowest_bit; /* index of first free in swap_map */ + unsigned int highest_bit; /* index of last free in swap_map */ + unsigned int pages; /* total of usable pages of swap */ + unsigned int inuse_pages; /* number of those currently in use */ + unsigned int cluster_next; /* likely index for next allocation */ + unsigned int cluster_nr; /* countdown to next cluster search */ + unsigned int lowest_alloc; /* while preparing discard cluster */ + unsigned int highest_alloc; /* while preparing discard cluster */ + struct swap_extent *curr_swap_extent; + struct swap_extent first_swap_extent; + struct block_device *bdev; /* swap device or bdev of swap file */ + struct file *swap_file; /* seldom referenced */ + unsigned int old_block_size; /* seldom referenced */ +}; + +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 lru_add_page_tail(struct zone* zone, + struct page *page, struct page *page_tail); +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 deactivate_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_file(struct page *page) +{ + __lru_cache_add(page, LRU_INACTIVE_FILE); +} + +/* LRU Isolation modes. */ +#define ISOLATE_INACTIVE 0 /* Isolate inactive pages. */ +#define ISOLATE_ACTIVE 1 /* Isolate active pages. */ +#define ISOLATE_BOTH 2 /* Isolate both active and inactive pages. */ + +/* 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 unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem, + gfp_t gfp_mask, bool noswap, + unsigned int swappiness, + struct zone *zone, + unsigned long *nr_scanned); +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; + +#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 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, + void __user *, size_t *, loff_t *); +#ifdef CONFIG_NUMA +extern int scan_unevictable_register_node(struct node *node); +extern void scan_unevictable_unregister_node(struct node *node); +#else +static inline int scan_unevictable_register_node(struct node *node) +{ + return 0; +} +static inline void scan_unevictable_unregister_node(struct node *node) +{ +} +#endif + +extern int kswapd_run(int nid); +extern void kswapd_stop(int nid); + +#ifdef CONFIG_SWAP +/* linux/mm/page_io.c */ +extern int swap_readpage(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 valid_swaphandles(swp_entry_t, unsigned long *); +extern int add_swap_count_continuation(swp_entry_t, gfp_t); +extern void swap_shmem_alloc(swp_entry_t); +extern int swap_duplicate(swp_entry_t); +extern int swapcache_prepare(swp_entry_t); +extern void swap_free(swp_entry_t); +extern void swapcache_free(swp_entry_t, struct page *page); +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 page *, struct block_device **); +extern sector_t swapdev_block(int, pgoff_t); +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(struct mm_struct *); +extern void __put_swap_token(struct mm_struct *); +extern void disable_swap_token(struct mem_cgroup *memcg); + +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); +} + +#ifdef CONFIG_CGROUP_MEM_RES_CTLR +extern void +mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout); +extern int mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep); +#else +static inline void +mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) +{ +} +#endif +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP +extern void mem_cgroup_uncharge_swap(swp_entry_t ent); +#else +static inline void mem_cgroup_uncharge_swap(swp_entry_t ent) +{ +} +#endif + +#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) \ + 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) +{ +} + +#define free_swap_and_cache(swp) is_migration_entry(swp) +#define swapcache_prepare(swp) is_migration_entry(swp) + +static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) +{ + return 0; +} + +static inline void swap_shmem_alloc(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 void swapcache_free(swp_entry_t swp, struct page *page) +{ +} + +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 */ +static inline void put_swap_token(struct mm_struct *mm) +{ +} + +static inline void grab_swap_token(struct mm_struct *mm) +{ +} + +static inline int has_swap_token(struct mm_struct *mm) +{ + return 0; +} + +static inline void disable_swap_token(struct mem_cgroup *memcg) +{ +} + +static inline void +mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent) +{ +} + +#ifdef CONFIG_CGROUP_MEM_RES_CTLR +static inline int +mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep) +{ + return 0; +} +#endif + +#endif /* CONFIG_SWAP */ +#endif /* __KERNEL__*/ +#endif /* _LINUX_SWAP_H */ |