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 zram.txt for more information.
Project home: http://compcache.googlecode.com/

source code:

drivers/staging/zram/