Why Qemu-KVM congesting my RAM?
 

Hi all,
I'm using a Host Based on Fedora 17, I've installed 16GB of RAM on this machine.
This host using KVM, running 2 CentOS 6.3 systems, each virtual guest assigned 2GB of RAM.
Everything is running just fine for couple of days since a reboot... though, after a few days my host OS ram starting to fulfill.
When checking I find several qemu-kvm processes using all of my RAM, why is this?
How can I solve it?

Hope you can assist me.
Attached is a screenshot of htop output.

Following some information I was able to retrieve using my friend Google friends...
I've set both guest OS, Virtio and IDE hard drives to work without cache - cache=none.

Hope it will solve my issue.
Will keep update this thread in couple of days.
If you got an idea also, or explanation how come the cache can eat all of my RAM (more than 10Gb) I would like to understand this kind of behavior.

Thanks in advance.