Expand 'compress_algorithm' mount option to accept parameter as format of
<algorithm>:<level>, by this way, it gives a way to allow user to do more
specified config on lz4 and zstd compression level, then f2fs compression
can provide higher compress ratio.
In order to set compress level for lz4 algorithm, it needs to set
CONFIG_LZ4HC_COMPRESS and CONFIG_F2FS_FS_LZ4HC config to enable lz4hc
compress algorithm.
CR and performance number on lz4/lz4hc algorithm:
dd if=enwik9 of=compressed_file conv=fsync
Original blocks: 244382
lz4 lz4hc-9
compressed blocks 170647 163270
compress ratio 69.8% 66.8%
speed 16.4207 s, 60.9 MB/s 26.7299 s, 37.4 MB/s
compress ratio = after / before
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
3fde13f817