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The blockdev book basically contains user-faced documentation. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
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zram: Compressed RAM based block devices
- Introduction
The zram module creates RAM based block devices named /dev/zram ( = 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/
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/admin-guide/blockdev/zram.rst