diff options
Diffstat (limited to 'include/linux/swap.h')
| -rw-r--r-- | include/linux/swap.h | 52 |
1 files changed, 43 insertions, 9 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h index d95cde5e257d..c03c139219c9 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -182,6 +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 { @@ -191,14 +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 */ @@ -212,14 +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 { @@ -414,6 +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 |