diff options
Diffstat (limited to 'fs/squashfs/Kconfig')
| -rw-r--r-- | fs/squashfs/Kconfig | 170 |
1 files changed, 167 insertions, 3 deletions
diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig index c70111ebefd4..a9602aae21ef 100644 --- a/fs/squashfs/Kconfig +++ b/fs/squashfs/Kconfig @@ -1,11 +1,12 @@ +# SPDX-License-Identifier: GPL-2.0-only config SQUASHFS tristate "SquashFS 4.0 - Squashed file system support" depends on BLOCK help Saying Y here includes support for SquashFS 4.0 (a Compressed Read-Only File System). Squashfs is a highly compressed read-only - filesystem for Linux. It uses zlib, lzo or xz compression to - compress both files, inodes and directories. Inodes in the system + filesystem for Linux. It uses zlib, lz4, lzo, xz or zstd compression + to compress both files, inodes and directories. Inodes in the system are very small and all blocks are packed to minimise data overhead. Block sizes greater than 4K are supported up to a maximum of 1 Mbytes (default block size 128K). SquashFS 4.0 supports 64 bit filesystems @@ -15,7 +16,7 @@ config SQUASHFS Squashfs is intended for general read-only filesystem use, for archival use (i.e. in cases where a .tar.gz file may be used), and in embedded systems where low overhead is needed. Further information - and tools are available from http://squashfs.sourceforge.net. + and tools are available from github.com/plougher/squashfs-tools. If you want to compile this as a module ( = code which can be inserted in and removed from the running kernel whenever you want), @@ -25,6 +26,119 @@ config SQUASHFS If unsure, say N. +choice + prompt "File decompression options" + depends on SQUASHFS + help + Squashfs now supports two options for decompressing file + data. Traditionally Squashfs has decompressed into an + intermediate buffer and then memcopied it into the page cache. + Squashfs now supports the ability to decompress directly into + the page cache. + + If unsure, select "Decompress file data into an intermediate buffer" + +config SQUASHFS_FILE_CACHE + bool "Decompress file data into an intermediate buffer" + help + Decompress file data into an intermediate buffer and then + memcopy it into the page cache. + +config SQUASHFS_FILE_DIRECT + bool "Decompress files directly into the page cache" + help + Directly decompress file data into the page cache. + Doing so can significantly improve performance because + it eliminates a memcpy and it also removes the lock contention + on the single buffer. + +endchoice + +config SQUASHFS_DECOMP_SINGLE + depends on SQUASHFS + def_bool n + +config SQUASHFS_DECOMP_MULTI + depends on SQUASHFS + def_bool n + +config SQUASHFS_DECOMP_MULTI_PERCPU + depends on SQUASHFS + def_bool n + +config SQUASHFS_CHOICE_DECOMP_BY_MOUNT + bool "Select the parallel decompression mode during mount" + depends on SQUASHFS + default n + select SQUASHFS_DECOMP_SINGLE + select SQUASHFS_DECOMP_MULTI + select SQUASHFS_DECOMP_MULTI_PERCPU + select SQUASHFS_MOUNT_DECOMP_THREADS + help + Compile all parallel decompression modes and specify the + decompression mode by setting "threads=" during mount. + default Decompressor parallelisation is SQUASHFS_DECOMP_SINGLE + +choice + prompt "Select decompression parallel mode at compile time" + depends on SQUASHFS + depends on !SQUASHFS_CHOICE_DECOMP_BY_MOUNT + help + Squashfs now supports three parallelisation options for + decompression. Each one exhibits various trade-offs between + decompression performance and CPU and memory usage. + + If in doubt, select "Single threaded compression" + +config SQUASHFS_COMPILE_DECOMP_SINGLE + bool "Single threaded compression" + select SQUASHFS_DECOMP_SINGLE + help + Traditionally Squashfs has used single-threaded decompression. + Only one block (data or metadata) can be decompressed at any + one time. This limits CPU and memory usage to a minimum. + +config SQUASHFS_COMPILE_DECOMP_MULTI + bool "Use multiple decompressors for parallel I/O" + select SQUASHFS_DECOMP_MULTI + help + By default Squashfs uses a single decompressor but it gives + poor performance on parallel I/O workloads when using multiple CPU + machines due to waiting on decompressor availability. + + If you have a parallel I/O workload and your system has enough memory, + using this option may improve overall I/O performance. + + This decompressor implementation uses up to two parallel + decompressors per core. It dynamically allocates decompressors + on a demand basis. + +config SQUASHFS_COMPILE_DECOMP_MULTI_PERCPU + bool "Use percpu multiple decompressors for parallel I/O" + select SQUASHFS_DECOMP_MULTI_PERCPU + help + By default Squashfs uses a single decompressor but it gives + poor performance on parallel I/O workloads when using multiple CPU + machines due to waiting on decompressor availability. + + This decompressor implementation uses a maximum of one + decompressor per core. It uses percpu variables to ensure + decompression is load-balanced across the cores. +endchoice + +config SQUASHFS_MOUNT_DECOMP_THREADS + bool "Add the mount parameter 'threads=' for squashfs" + depends on SQUASHFS + depends on SQUASHFS_DECOMP_MULTI + default n + help + Use threads= to set the decompression parallel mode and the number of threads. + If SQUASHFS_CHOICE_DECOMP_BY_MOUNT=y + threads=<single|multi|percpu|1|2|3|...> + else + threads=<2|3|...> + The upper limit is num_online_cpus() * 2. + config SQUASHFS_XATTR bool "Squashfs XATTR support" depends on SQUASHFS @@ -35,6 +149,27 @@ config SQUASHFS_XATTR If unsure, say N. +config SQUASHFS_COMP_CACHE_FULL + bool "Enable full caching of compressed blocks" + depends on SQUASHFS + default n + help + This option enables caching of all compressed blocks, Without caching, + repeated reads of the same files trigger excessive disk I/O, significantly + reducinng performance in workloads like fio-based benchmarks. + + For example, fio tests (iodepth=1, numjobs=1, ioengine=psync) show: + With caching: IOPS=2223, BW=278MiB/s (291MB/s) + Without caching: IOPS=815, BW=102MiB/s (107MB/s) + + Enabling this option restores performance to pre-regression levels by + caching all compressed blocks in the page cache, reducing disk I/O for + repeated reads. However, this increases memory usage, which may be a + concern in memory-constrained environments. + + Enable this option if your workload involves frequent repeated reads and + memory usage is not a limiting factor. If unsure, say N. + config SQUASHFS_ZLIB bool "Include support for ZLIB compressed file systems" depends on SQUASHFS @@ -48,6 +183,21 @@ config SQUASHFS_ZLIB If unsure, say Y. +config SQUASHFS_LZ4 + bool "Include support for LZ4 compressed file systems" + depends on SQUASHFS + select LZ4_DECOMPRESS + help + Saying Y here includes support for reading Squashfs file systems + compressed with LZ4 compression. LZ4 compression is mainly + aimed at embedded systems with slower CPUs where the overheads + of zlib are too high. + + LZ4 is not the standard compression used in Squashfs and so most + file systems will be readable without selecting this option. + + If unsure, say N. + config SQUASHFS_LZO bool "Include support for LZO compressed file systems" depends on SQUASHFS @@ -78,6 +228,20 @@ config SQUASHFS_XZ If unsure, say N. +config SQUASHFS_ZSTD + bool "Include support for ZSTD compressed file systems" + depends on SQUASHFS + select ZSTD_DECOMPRESS + help + Saying Y here includes support for reading Squashfs file systems + compressed with ZSTD compression. ZSTD gives better compression than + the default ZLIB compression, while using less CPU. + + ZSTD is not the standard compression used in Squashfs and so most + file systems will be readable without selecting this option. + + If unsure, say N. + config SQUASHFS_4K_DEVBLK_SIZE bool "Use 4K device block size?" depends on SQUASHFS |