VSwapper
Nadav Amit, Dan Tsafrir, Assaf Schuster · 2014
The number of guest virtual machines that can be consolidated on one physical host is typically limited by the memory size, motivating memory overcommitment. Guests are given a choice to either install a "balloon" driver to coordinate the overcommitment activity, or to experience degraded performance due to uncooperative swapping. Ballooning, however, is not a complete solution, as hosts must still fall back on uncooperative swapping in various circumstances. Additionally, ballooning takes time to accommodate change, and so guests might experience degraded performance under changing conditions.