Collaborative memory management in hosted linux environments

In hosted environments, multiple guest operat-ing systems are hosted on top of a host operat-ing system or hypervisor. The problem of over-committing physical memory is either solved by dynamically adjusting the memory sizes of the guests or through transparent host paging. Both approaches can introduce significant over-head in heavily overcommitted memory sce-narios due to frequent resize requests or due to high paging I/O activity. This paper intro-duces a novel approach to this problem, called collaborative memory management (CMM). In CMM, guests and host operating system ex-change page usage and residency information. This information is primarily used by the host to reduce the amount of paging it needs to do for the pages of its guests. The CMM design and the Linux implementation and a prototype for Linux for zSeries and the z/VM hypervisor will be discussed.