diff options
Diffstat (limited to 'include/linux/swap.h')
| -rw-r--r-- | include/linux/swap.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h index d95cde5e257d..cb5baebf31d6 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -182,6 +182,23 @@ 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 */ + +/* * The in-memory structure used to track swap areas. */ struct swap_info_struct { @@ -191,6 +208,9 @@ 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 */ |