Xen memory balloon driver

modulename: xen-balloon.ko

configname: CONFIG_XEN_BALLOON

Linux Kernel Configuration
└─>Device Drivers
└─>Xen driver support
└─>Xen memory balloon driver
In linux kernel since version 2.6.26 (release Date: 2008-07-13)  
The balloon driver allows the Xen domain to request more memory from
the system to expand the domain's memory allocation, or alternatively
return unneeded memory to the system.

source code:
depends
CONFIG_XEN