diff options
Diffstat (limited to 'kernel/include/linux/swap.h')
| -rw-r--r-- | kernel/include/linux/swap.h | 545 |
1 files changed, 545 insertions, 0 deletions
diff --git a/kernel/include/linux/swap.h b/kernel/include/linux/swap.h new file mode 100644 index 000000000..4c07c12d2 --- /dev/null +++ b/kernel/include/linux/swap.h @@ -0,0 +1,545 @@ +#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 <linux/fs.h> +#include <linux/atomic.h> +#include <linux/page-flags.h> +#include <linux/locallock.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 /* enable discard for swap */ +#define SWAP_FLAG_DISCARD_ONCE 0x20000 /* discard swap area at swapon-time */ +#define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */ + +#define SWAP_FLAGS_VALID (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \ + SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \ + SWAP_FLAG_DISCARD_PAGES) + +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; +}; + +/* + * 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), /* 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 */ + SWP_FILE = (1 << 7), /* set after swap_activate success */ + SWP_AREA_DISCARD = (1 << 8), /* single-time swap area discards */ + SWP_PAGE_DISCARD = (1 << 9), /* freed swap page-cluster discards */ + /* add others here before... */ + SWP_SCANNING = (1 << 10), /* refcount in scan_swap_map */ +}; + +#define SWAP_CLUSTER_MAX 32UL +#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX + +/* + * Ratio between zone->managed_pages and the "gap" that above the per-zone + * "high_wmark". While balancing nodes, We allow kswapd to shrink zones that + * do not meet the (high_wmark + gap) watermark, even which already met the + * high_wmark, 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 */ + +/* + * We use this to track usage of a cluster. A cluster is a block of swap disk + * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All + * free clusters are organized into a list. We fetch an entry from the list to + * get a free cluster. + * + * The data field stores next cluster if the cluster is free or cluster usage + * counter otherwise. The flags field determines if a cluster is free. This is + * protected by swap_info_struct.lock. + */ +struct swap_cluster_info { + unsigned int data:24; + unsigned int flags:8; +}; +#define CLUSTER_FLAG_FREE 1 /* This cluster is free */ +#define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */ + +/* + * We assign a cluster to each CPU, so each CPU can allocate swap entry from + * its own cluster and swapout sequentially. The purpose is to optimize swapout + * throughput. + */ +struct percpu_cluster { + struct swap_cluster_info index; /* Current cluster index */ + unsigned int next; /* Likely next allocation offset */ +}; + +/* + * 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 */ + struct plist_node list; /* entry in swap_active_head */ + struct plist_node avail_list; /* entry in swap_avail_head */ + signed char type; /* strange name for an index */ + unsigned int max; /* extent of the swap_map */ + unsigned char *swap_map; /* vmalloc'ed array of usage counts */ + struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */ + struct swap_cluster_info free_cluster_head; /* free cluster list head */ + struct swap_cluster_info free_cluster_tail; /* free cluster list tail */ + 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 */ + struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */ + 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 */ +#ifdef CONFIG_FRONTSWAP + unsigned long *frontswap_map; /* frontswap in-use, one bit per page */ + atomic_t frontswap_pages; /* frontswap pages in-use counter */ +#endif + spinlock_t lock; /* + * protect map scan related fields like + * swap_map, lowest_bit, highest_bit, + * inuse_pages, cluster_next, + * cluster_nr, lowest_alloc, + * highest_alloc, free/discard cluster + * list. other fields are only changed + * at swapon/swapoff, so are protected + * by swap_lock. changing flags need + * hold this lock and swap_lock. If + * both locks need hold, hold swap_lock + * first. + */ + struct work_struct discard_work; /* discard worker */ + struct swap_cluster_info discard_cluster_head; /* list head of discard clusters */ + struct swap_cluster_info discard_cluster_tail; /* list tail of discard clusters */ +}; + +/* linux/mm/workingset.c */ +void *workingset_eviction(struct address_space *mapping, struct page *page); +bool workingset_refault(void *shadow); +void workingset_activation(struct page *page); +extern struct list_lru __workingset_shadow_nodes; +DECLARE_LOCAL_IRQ_LOCK(workingset_shadow_lock); + +static inline unsigned int workingset_node_pages(struct radix_tree_node *node) +{ + return node->count & RADIX_TREE_COUNT_MASK; +} + +static inline void workingset_node_pages_inc(struct radix_tree_node *node) +{ + node->count++; +} + +static inline void workingset_node_pages_dec(struct radix_tree_node *node) +{ + node->count--; +} + +static inline unsigned int workingset_node_shadows(struct radix_tree_node *node) +{ + return node->count >> RADIX_TREE_COUNT_SHIFT; +} + +static inline void workingset_node_shadows_inc(struct radix_tree_node *node) +{ + node->count += 1U << RADIX_TREE_COUNT_SHIFT; +} + +static inline void workingset_node_shadows_dec(struct radix_tree_node *node) +{ + node->count -= 1U << RADIX_TREE_COUNT_SHIFT; +} + +/* linux/mm/page_alloc.c */ +extern unsigned long totalram_pages; +extern unsigned long totalreserve_pages; +extern unsigned long dirty_balance_reserve; +extern unsigned long nr_free_buffer_pages(void); +extern unsigned long 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 */ +DECLARE_LOCAL_IRQ_LOCK(swapvec_lock); +extern void lru_cache_add(struct page *); +extern void lru_cache_add_anon(struct page *page); +extern void lru_cache_add_file(struct page *page); +extern void lru_add_page_tail(struct page *page, struct page *page_tail, + struct lruvec *lruvec, struct list_head *head); +extern void activate_page(struct page *); +extern void mark_page_accessed(struct page *); +extern void lru_add_drain(void); +extern void lru_add_drain_cpu(int cpu); +extern void lru_add_drain_all(void); +extern void rotate_reclaimable_page(struct page *page); +extern void deactivate_file_page(struct page *page); +extern void swap_setup(void); + +extern void add_page_to_unevictable_list(struct page *page); + +extern void lru_cache_add_active_or_unevictable(struct page *page, + struct vm_area_struct *vma); + +/* linux/mm/vmscan.c */ +extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, + gfp_t gfp_mask, nodemask_t *mask); +extern int __isolate_lru_page(struct page *page, isolate_mode_t mode); +extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, + unsigned long nr_pages, + gfp_t gfp_mask, + bool may_swap); +extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem, + gfp_t gfp_mask, bool noswap, + struct zone *zone, + unsigned long *nr_scanned); +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 unsigned 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); +extern void check_move_unevictable_pages(struct page **, int nr_pages); + +extern int kswapd_run(int nid); +extern void kswapd_stop(int nid); +#ifdef CONFIG_MEMCG +extern int mem_cgroup_swappiness(struct mem_cgroup *mem); +#else +static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) +{ + return vm_swappiness; +} +#endif +#ifdef CONFIG_MEMCG_SWAP +extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry); +extern void mem_cgroup_uncharge_swap(swp_entry_t entry); +#else +static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry) +{ +} +static inline void mem_cgroup_uncharge_swap(swp_entry_t entry) +{ +} +#endif +#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_write(struct bio *bio, int err); +extern int __swap_writepage(struct page *page, struct writeback_control *wbc, + void (*end_write_func)(struct bio *, int)); +extern int swap_set_page_dirty(struct page *page); +extern void end_swap_bio_read(struct bio *bio, int err); + +int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, + unsigned long nr_pages, sector_t start_block); +int generic_swapfile_activate(struct swap_info_struct *, struct file *, + sector_t *); + +/* linux/mm/swap_state.c */ +extern struct address_space swapper_spaces[]; +#define swap_address_space(entry) (&swapper_spaces[swp_type(entry)]) +extern unsigned long total_swapcache_pages(void); +extern void show_swap_cache_info(void); +extern int add_to_swap(struct page *, struct list_head *list); +extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t); +extern int __add_to_swap_cache(struct page *page, swp_entry_t entry); +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 atomic_long_t nr_swap_pages; +extern long total_swap_pages; + +/* Swap 50% full? Release swapcache more aggressively.. */ +static inline bool vm_swap_full(void) +{ + return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages; +} + +static inline long get_nr_swap_pages(void) +{ + return atomic_long_read(&nr_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 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); +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 page_swapcount(struct page *); +extern struct swap_info_struct *page_swap_info(struct page *); +extern int reuse_swap_page(struct page *); +extern int try_to_free_swap(struct page *); +struct backing_dev_info; + +#else /* CONFIG_SWAP */ + +#define swap_address_space(entry) (NULL) +#define get_nr_swap_pages() 0L +#define total_swap_pages 0L +#define total_swapcache_pages() 0UL +#define vm_swap_full() 0 + +#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), false); + +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) +{ +} + +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, struct list_head *list) +{ + 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) +{ +} + +static inline int page_swapcount(struct page *page) +{ + return 0; +} + +#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; +} + +#endif /* CONFIG_SWAP */ +#endif /* __KERNEL__*/ +#endif /* _LINUX_SWAP_H */ |