I was looking at the following item in the backlog:

Guests Stats: Display memory utilization (use virt-df or virt-top or ...)

If I understood it right, the idea here is to show the -inner- memory allocation of the guest. If you have a VM with 4Gb of RAM running an Ubuntu, we want to know how much memory the Ubuntu OS and its processes are using.

I've done an investigation and I haven't found any tool to accomplish this. "virt-top", "virsh dommemstat" and the libvirt API retrieves the information of the memory usage of the guest relative to the host. In the example mentioned before, supposing that the host has 64Gb of RAM, all these tools would show that the VM is using 12% of the host RAM. They do not dive in the VM and shows the actual mem usage of the Ubuntu and its processes running there.

Haven't found anything useful in other MLs and forums. The common answer is 'run top in a terminal inside the VM', which of course does not suit us. My question is: any thoughts about how we can implement this feature? Because I am starting to think that, in the end, this kind of info is strict to the guest OS and can't be polled from the outside.