Subject: Re: [virtio] [OASIS Issue Tracker] Created: (VIRTIO-28) Implement new balloon device (ID 13)
Amit Shah <firstname.lastname@example.org> writes: > On (Wed) 11 Sep 2013 [04:51:39], OASIS Issues Tracker wrote: >> Implement new balloon device (ID 13) >> ------------------------------------ >> >> Key: VIRTIO-28 >> URL: http://tools.oasis-open.org/issues/browse/VIRTIO-28 >> Project: OASIS Virtual I/O Device (VIRTIO) TC >> Issue Type: New Feature >> Reporter: Rusty Russell >> >> >> The current virtio balloon device is bad enough that fixing it yields something completely incompatible: >> 1) The page size is 4096, always, rather than some configurable page size. >> 2) Page numbers are 32 bits. >> 3) The deflate queue is not actually used by any device implementation (see issue virtio-25). >> 4) The "actual" number is kind of useless, and (along with the deflate queue) requires the guest to track pages, rather than just faulting them in. >> 5) The config is little-endian by mistake (may not matter). > > The current design is weird: the host tells the guest the offset by > which to inflate or deflate the balloon. Instead, the host should let > the guest know how much in absolute terms the memory should be > adjusted to, and the guest will take the decision on whether to > inflate, or deflate, or not take any action at all. I see your point. I wonder how east it is define how much memory the guest has (from a guest perspective). Things like memory holes, device memory maps and I'm sure there is other platform-specific weirdness I'm sure I don't understand. I could be wrong though? Rusty.