Hi folks, This patchset is mainly intended for the upcoming LZMA preparation, but they still have some benefits to the exist LZ4 decompression.
The first patch looks up compression algorithms on mapping instead of in the decompression frontend, which is used for the rest patches. The second patch introduces another compression HEAD (HEAD2) so that each file can be compressed with two different algorithms at most, which can be used for the upcoming LZMA compression and LZ4 range dictionary compression for different data/access patterns. The third patch introduces a new readmore decompression strategy trying to improve randread for large LZ4 big pcluster and the upcoming LZMA decompression. It mainly addresses the previous issue mentioned in the original big pcluster patchset [1]: FIO randread Testdata: enwik9 Kernel: Linux 5.15.0-rc2 pclustersize Vanilla Patched 4096 54.6 MiB/s 56.1 MiB/s 16384 117.4 MiB/s 145.6 MiB/s 32768 113.6 MiB/s 203.4 MiB/s 65536 72.8 MiB/s 236.1 MiB/s The latest version can also be fetched from git://git.kernel.org/pub/scm/linux/kernel/git/xiang/linux.git -b erofs/readmore [1] https://lore.kernel.org/r/[email protected] Thanks, Gao Xiang Changes since v1: - correct the function name to z_erofs_map_blocks_iter() in the commit message pointed out by Yue; - fix the readmore logic which mainly impacts the LZMA approach later, therefore test the Patched version again. Gao Xiang (3): erofs: get compression algorithms directly on mapping erofs: introduce the secondary compression head erofs: introduce readmore decompression strategy fs/erofs/compress.h | 5 -- fs/erofs/erofs_fs.h | 8 ++- fs/erofs/internal.h | 25 +++++++- fs/erofs/zdata.c | 111 +++++++++++++++++++++++++++-------- fs/erofs/zmap.c | 55 +++++++++++------ include/trace/events/erofs.h | 2 +- 6 files changed, 151 insertions(+), 55 deletions(-) -- 2.20.1
