Compressed RAM block device support

modulename:  zram.ko

configname: CONFIG_ZRAM

Linux Kernel Configuration
└─>Device Drivers
└─>Block devices
└─>Compressed RAM block device support
In linux kernel since version 2.6.36 (release Date: 2010-10-20)  
Creates virtual block devices called /dev/zramX (X = 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.

It has several use cases, for example: /tmp storage, use as swap
disks and maybe many more.

See Documentation/admin-guide/blockdev/zram.rst for more information.

source code: