From 622ceaddb7649ca328832f50ba1400af778d75fa Mon Sep 17 00:00:00 2001 From: Gao Xiang Date: Mon, 11 Oct 2021 05:31:45 +0800 Subject: erofs: lzma compression support Add MicroLZMA support in order to maximize compression ratios for specific scenarios. For example, it's useful for low-end embedded boards and as a secondary algorithm in a file for specific access patterns. MicroLZMA is a new container format for raw LZMA1, which was created by Lasse Collin aiming to minimize old LZMA headers and get rid of unnecessary EOPM (end of payload marker) as well as to enable fixed-sized output compression, especially for 4KiB pclusters. Similar to LZ4, inplace I/O approach is used to minimize runtime memory footprint when dealing with I/O. Overlapped decompression is handled with 1) bounced buffer for data under processing or 2) extra short-lived pages from the on-stack pagepool which will be shared in the same read request (128KiB for example). Link: https://lore.kernel.org/r/20211010213145.17462-8-xiang@kernel.org Acked-by: Chao Yu Signed-off-by: Gao Xiang --- fs/erofs/Kconfig | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'fs/erofs/Kconfig') diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig index addfe608d08e..f57255ab88ed 100644 --- a/fs/erofs/Kconfig +++ b/fs/erofs/Kconfig @@ -82,3 +82,19 @@ config EROFS_FS_ZIP Enable fixed-sized output compression for EROFS. If you don't want to enable compression feature, say N. + +config EROFS_FS_ZIP_LZMA + bool "EROFS LZMA compressed data support" + depends on EROFS_FS_ZIP + select XZ_DEC + select XZ_DEC_MICROLZMA + help + Saying Y here includes support for reading EROFS file systems + containing LZMA compressed data, specifically called microLZMA. it + gives better compression ratios than the LZ4 algorithm, at the + expense of more CPU overhead. + + LZMA support is an experimental feature for now and so most file + systems will be readable without selecting this option. + + If unsure, say N. -- cgit v1.2.3