[libvirt] [RFD] API for reporting virtual machine memory statistics

I am working on a feature that enables virtual machines to report memory statistics to the host. Examples include: free memory, number of pages swapped out/in, number of page faults, etc. This information is useful to a virtual machine manager which can use it to make memory ballooning or VM migration decisions. My implementation uses the virtio-balloon driver as a conduit for the memory info. What is the best way to expose these memory stats in libvirt? I see two possibilities. The dominfo command already queries the balloon driver so I could easily extend this command to report the additional fields. The second, and better IMO, option is to introduce a new command (dommemstat) with output similar to domblkstat. What do you think? -- Thanks, Adam