Squashfs: add multi-threaded decompression using percpu variable

[firefly-linux-kernel-4.4.55.git] / fs / squashfs / Kconfig

diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
index 1c6d340fc61f868570cbe1323ac56ae265cd19eb..159bd6676dc2f652cab5a947de88377ffae9c690 100644 (file)
--- a/fs/squashfs/Kconfig
+++ b/fs/squashfs/Kconfig
@@ -25,6 +25,50 @@ config SQUASHFS
 
          If unsure, say N.
 
+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
@@ -63,19 +107,6 @@ config SQUASHFS_LZO
 
          If unsure, say N.
 
-config SQUASHFS_MULTI_DECOMPRESSOR
-       bool "Use multiple decompressors for handling parallel I/O"
-       depends on SQUASHFS
-       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.
-
-         If unsure, say N.
-
 config SQUASHFS_XZ
        bool "Include support for XZ compressed file systems"
        depends on SQUASHFS