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alistair23-linux/tools/testing/selftests/zram
Thomas Gleixner 7170066ecd treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 25
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it would be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 6 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Jilayne Lovejoy <opensource@jilayne.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154043.007767574@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 11:52:39 +02:00
..
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
README selftests/zram: replace ZRAM_LZ4_COMPRESS 2016-09-20 09:00:01 -06:00
config selftests: create test-specific kconfig fragments 2016-02-25 09:47:52 -07:00
zram.sh selftests: zram: return Kselftest Skip code for skipped tests 2018-06-18 09:11:09 -06:00
zram01.sh treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 25 2019-05-21 11:52:39 +02:00
zram02.sh treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 25 2019-05-21 11:52:39 +02:00
zram_lib.sh treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 25 2019-05-21 11:52:39 +02:00

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_CRYPTO_LZ4=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