Merge tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck...

[linux-drm-fsl-dcu.git] / fs / squashfs / Kconfig

diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
index c70111ebefd44aaacf7248e10a5e80fecc06582a..b6fa8657dcbc51dcb904a7e5b018d474c94d9d83 100644 (file)
--- a/fs/squashfs/Kconfig
+++ b/fs/squashfs/Kconfig
@@ -25,6 +25,78 @@ 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
+
+choice
+       prompt "Decompressor parallelisation options"
+       depends on SQUASHFS
+       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_DECOMP_SINGLE
+       bool "Single threaded compression"
+       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_DECOMP_MULTI
+       bool "Use multiple decompressors for parallel I/O"
+       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_DECOMP_MULTI_PERCPU
+       bool "Use percpu multiple decompressors for parallel I/O"
+       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_XATTR
        bool "Squashfs XATTR support"
        depends on SQUASHFS