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authorPhillip Lougher <phillip@squashfs.org.uk>2011-10-22 01:34:48 +0100
committerPhillip Lougher <phillip@squashfs.org.uk>2011-11-02 17:25:50 +0000
commit7657cacf478940b995c2c73fdff981c13cc62c5c (patch)
treeb25b27a5ba475ebc3923657dcc14ee958d244493 /fs/squashfs/Kconfig
parentc3b92c8787367a8bb53d57d9789b558f1295cc96 (diff)
downloadop-kernel-dev-7657cacf478940b995c2c73fdff981c13cc62c5c.zip
op-kernel-dev-7657cacf478940b995c2c73fdff981c13cc62c5c.tar.gz
Squashfs: Add an option to set dev block size to 4K
This commit adds an option to set the device block size used to 4K. By default Squashfs sets the device block size (sb_min_blocksize) to 1K or the smallest block size supported by the block device (if larger). This, because blocks are packed together and unaligned in Squashfs, should reduce latency. This, however, gives poor performance on MTD NAND devices where the optimal I/O size is 4K (even though the devices can support smaller block sizes). Using a 4K device block size may also improve overall I/O performance for some file access patterns (e.g. sequential accesses of files in filesystem order) on all media. Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Diffstat (limited to 'fs/squashfs/Kconfig')
-rw-r--r--fs/squashfs/Kconfig22
1 files changed, 22 insertions, 0 deletions
diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
index 1360d4f..5586011 100644
--- a/fs/squashfs/Kconfig
+++ b/fs/squashfs/Kconfig
@@ -78,6 +78,28 @@ config SQUASHFS_XZ
If unsure, say N.
+config SQUASHFS_4K_DEVBLK_SIZE
+ bool "Use 4K device block size?"
+ depends on SQUASHFS
+ help
+ By default Squashfs sets the dev block size (sb_min_blocksize)
+ to 1K or the smallest block size supported by the block device
+ (if larger). This, because blocks are packed together and
+ unaligned in Squashfs, should reduce latency.
+
+ This, however, gives poor performance on MTD NAND devices where
+ the optimal I/O size is 4K (even though the devices can support
+ smaller block sizes).
+
+ Using a 4K device block size may also improve overall I/O
+ performance for some file access patterns (e.g. sequential
+ accesses of files in filesystem order) on all media.
+
+ Setting this option will force Squashfs to use a 4K device block
+ size by default.
+
+ If unsure, say N.
+
config SQUASHFS_EMBEDDED
bool "Additional option for memory-constrained systems"
depends on SQUASHFS
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