KVM Forum 2018

KVM guest suffers a major setback when it comes to freeing the unused memory. With the current implementation, when a guest frees certain memory chunk its availability for reuse is never communicated back to the host. Due to which the host fails to reclaim the memory freed by the guest for any other purpose. This talk presents the idea of guest free page hinting for efficiently handing freed memory between the guest and the host. This presentation also briefly covers memory ballooning and its pros and cons compared to this approach, the current design, challenges, performance, and possible improvement areas.