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

[Adam Litke]

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