config XEN_BALLOON bool "Xen memory balloon driver" depends on XEN default y help 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. config XEN_SCRUB_PAGES bool "Scrub pages before returning them to system" depends on XEN_BALLOON default y help Scrub pages before returning them to the system for reuse by other domains. This makes sure that any confidential data is not accidentally visible to other domains. Is it more secure, but slightly less efficient. If in doubt, say yes.