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authorLinus Torvalds <torvalds@linux-foundation.org>2011-11-04 16:48:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-11-04 16:48:37 -0700
commit044595d4e448305fbaec472eb7d22636d24e7d8c (patch)
tree5faee830194d778a9bb63317bc6ff7f8962a976b /fs
parent1583171492eb514e267c7b51e96846b38de0f544 (diff)
parent7657cacf478940b995c2c73fdff981c13cc62c5c (diff)
downloadlinux-stericsson-044595d4e448305fbaec472eb7d22636d24e7d8c.tar.gz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-next
* git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-next: Squashfs: Add an option to set dev block size to 4K
Diffstat (limited to 'fs')
-rw-r--r--fs/squashfs/Kconfig22
-rw-r--r--fs/squashfs/squashfs_fs.h7
-rw-r--r--fs/squashfs/super.c2
3 files changed, 30 insertions, 1 deletions
diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
index 048b59d5b2f0..c70111ebefd4 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
diff --git a/fs/squashfs/squashfs_fs.h b/fs/squashfs/squashfs_fs.h
index b4a4e539a08c..e8e14645de9a 100644
--- a/fs/squashfs/squashfs_fs.h
+++ b/fs/squashfs/squashfs_fs.h
@@ -36,6 +36,13 @@
#define SQUASHFS_FILE_SIZE 131072
#define SQUASHFS_FILE_LOG 17
+/* default size of block device I/O */
+#ifdef CONFIG_SQUASHFS_4K_DEVBLK_SIZE
+#define SQUASHFS_DEVBLK_SIZE 4096
+#else
+#define SQUASHFS_DEVBLK_SIZE 1024
+#endif
+
#define SQUASHFS_FILE_MAX_SIZE 1048576
#define SQUASHFS_FILE_MAX_LOG 20
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
index 7438850c62d0..2da1715452ac 100644
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -95,7 +95,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
}
msblk = sb->s_fs_info;
- msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE);
+ msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE);
msblk->devblksize_log2 = ffz(~msblk->devblksize);
mutex_init(&msblk->read_data_mutex);