diff options
Diffstat (limited to 'include/linux/swap.h')
| -rw-r--r-- | include/linux/swap.h | 78 |
1 files changed, 60 insertions, 18 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h index 1701ce4be746..46ba0c6c219f 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -10,6 +10,7 @@ #include <linux/node.h> #include <linux/fs.h> #include <linux/atomic.h> +#include <linux/page-flags.h> #include <asm/page.h> struct notifier_block; @@ -19,10 +20,13 @@ 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 */ +#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 | SWAP_FLAG_DISCARD_ONCE | \ + SWAP_FLAG_DISCARD_PAGES) static inline int current_is_kswapd(void) { @@ -146,14 +150,16 @@ struct swap_extent { 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_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 << 8), /* refcount in scan_swap_map */ + SWP_SCANNING = (1 << 10), /* refcount in scan_swap_map */ }; #define SWAP_CLUSTER_MAX 32UL @@ -176,6 +182,33 @@ enum { #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 { @@ -185,14 +218,16 @@ struct swap_info_struct { 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 */ + 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 */ - unsigned int lowest_alloc; /* while preparing discard cluster */ - unsigned int highest_alloc; /* while preparing discard cluster */ + 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 */ @@ -206,14 +241,18 @@ struct swap_info_struct { * protect map scan related fields like * swap_map, lowest_bit, highest_bit, * inuse_pages, cluster_next, - * cluster_nr, lowest_alloc and - * highest_alloc. 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. + * 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 */ }; struct swap_list_t { @@ -233,15 +272,15 @@ extern unsigned long nr_free_pagecache_pages(void); /* 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_cache_add(struct page *); +extern void lru_cache_add(struct 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 int lru_add_drain_all(void); +extern void 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); @@ -254,12 +293,14 @@ extern void add_page_to_unevictable_list(struct page *page); */ static inline void lru_cache_add_anon(struct page *page) { - __lru_cache_add(page, LRU_INACTIVE_ANON); + ClearPageActive(page); + __lru_cache_add(page); } static inline void lru_cache_add_file(struct page *page) { - __lru_cache_add(page, LRU_INACTIVE_FILE); + ClearPageActive(page); + __lru_cache_add(page); } /* linux/mm/vmscan.c */ @@ -406,6 +447,7 @@ mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) #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 |