Is there a way to transparently reclaim, or prevent usage of, memory from a qemu-kvm guest?
A guest uses 8GB of RAM during peak hours, it returns back to 4GB of usage at night, but the guest is still claiming 8GB of RAM from the host.
A guest uses 2GB of RAM, but has 6GB of RAM in page cache. The guest is claiming 8GB of RAM from the host, but up to 6GB of it could be RAM that could be have more importance in another guest system.
My first thoughts on ballooning was that the guest would not "see" the ballooning effect, but when sending "balloon 2048", the memory inside the guest is actually reduced to ~2GB.