diff options
Diffstat (limited to 'fs/btrfs/compression.h')
| -rw-r--r-- | fs/btrfs/compression.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h index cfcec709c61b..619e64c27444 100644 --- a/fs/btrfs/compression.h +++ b/fs/btrfs/compression.h @@ -19,6 +19,21 @@ #ifndef __BTRFS_COMPRESSION_ #define __BTRFS_COMPRESSION_ +/* + * We want to make sure that amount of RAM required to uncompress an extent is + * reasonable, so we limit the total size in ram of a compressed extent to + * 128k. This is a crucial number because it also controls how easily we can + * spread reads across cpus for decompression. + * + * We also want to make sure the amount of IO required to do a random read is + * reasonably small, so we limit the size of a compressed extent to 128k. + */ + +/* Maximum length of compressed data stored on disk */ +#define BTRFS_MAX_COMPRESSED (SZ_128K) +/* Maximum size of data before compression */ +#define BTRFS_MAX_UNCOMPRESSED (SZ_128K) + void btrfs_init_compress(void); void btrfs_exit_compress(void); |