linux

History

Zhang Zhen 7ef7cc9fdf seltests/zram: fix syntax error Not all shells define a variable UID. This is a bash and zsh feature only. In other shells, the UID variable is not defined, so here test command expands to [ != 0 ] which is a syntax error. Without this patch: root@HGH1000007090:/opt/work/linux/tools/testing/selftests/zram# sh zram.sh zram.sh: 8: [: !=: unexpected operator zram.sh : No zram.ko module or /dev/zram0 device file not found zram.sh : CONFIG_ZRAM is not set With this patch: root@HGH1000007090:/opt/work/linux/tools/testing/selftests/zram# sh ./zram.sh zram.sh : No zram.ko module or /dev/zram0 device file not found zram.sh : CONFIG_ZRAM is not set Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>		2015-09-14 16:40:57 -06:00
..
Makefile	selftests/zram: Makefile fix	2015-09-01 10:52:25 -06:00
README	…
zram.sh	seltests/zram: fix syntax error	2015-09-14 16:40:57 -06:00
zram01.sh	selftests/zram: must be run as root	2015-09-01 10:51:32 -06:00
zram02.sh	selftests/zram: must be run as root	2015-09-01 10:51:32 -06:00
zram_lib.sh	seltests/zram: fix syntax error	2015-09-14 16:40:57 -06:00

README

zram: Compressed RAM based block devices
----------------------------------------
* Introduction

The zram module creates RAM based block devices named /dev/zram<id>
(<id> = 0, 1, ...). Pages written to these disks are compressed and stored
in memory itself. These disks allow very fast I/O and compression provides
good amounts of memory savings. Some of the usecases include /tmp storage,
use as swap disks, various caches under /var and maybe many more :)

Statistics for individual zram devices are exported through sysfs nodes at
/sys/block/zram<id>/

Kconfig required:
CONFIG_ZRAM=y
CONFIG_ZRAM_LZ4_COMPRESS=y
CONFIG_ZPOOL=y
CONFIG_ZSMALLOC=y

ZRAM Testcases
--------------
zram_lib.sh: create library with initialization/cleanup functions
zram.sh: For sanity check of CONFIG_ZRAM and to run zram01 and zram02

Two functional tests: zram01 and zram02:
zram01.sh: creates general purpose ram disks with ext4 filesystems
zram02.sh: creates block device for swap

Commands required for testing:
 - bc
 - dd
 - free
 - awk
 - mkswap
 - swapon
 - swapoff
 - mkfs/ mkfs.ext4

For more information please refer:
kernel-source-tree/Documentation/blockdev/zram.txt