The following patch-set proposes an efficient mechanism for handing freed memory between the guest and the host. It enables the guests with DAX (no page cache) to rapidly free and reclaim memory to and from the host respectively. Changelog in V3: -A new hinting_vq is added to virtio_balloon for the usage of guest page hinting -Implmentation to pass hyperlist entries to the host via hinting_vq -Basic functional testing for this support is done Virtio interface changes are picked up from Wei's patch-set for Virtio-balloon enhancement[3]. "Wei, How would you like me to credit you in the final patch?") [1] http://www.spinics.net/lists/kvm/msg153666.html [2] https://www.spinics.net/lists/kvm/msg155471.html [3] http://www.spinics.net/lists/kvm/msg152734.html