diff options
| -rw-r--r-- | fs/squashfs/Kconfig | 22 | ||||
| -rw-r--r-- | fs/squashfs/squashfs_fs.h | 7 | ||||
| -rw-r--r-- | fs/squashfs/super.c | 2 |
3 files changed, 30 insertions, 1 deletions
diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig index 1360d4f88f41..5586011b6a38 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); |