KVM call minutes for June 15

Chris Wright
2010-06-15T15:18:14Z

Page cache controls
- cache is 60% duplicated between host and guest (when not using cache=none)
- Balbir posted 2 patches to eliminate this
- boot parameter for preferred reclaim
- not always have balloon driver
- need a boot parameter
- perhaps add a balloon cmd to give a hint before a more forceful request
- hard/soft quota
- exceed hard, swap
- exceed soft...no real penalty
- another consideration, block device hint (has large cache in host, don't
agressively cache in guest)
- lru weighted by disk speed might make sense on bare metal
- balloon driver filter
- balloon unmapped page cache pages first
- guest has no incentive to cooperate (give up memory and possibly performance)

Migration Subsections
- looks good...
- doesn't replace need to increment version numbers
- needs some documentation to make sure subtlties are clear
- size for each section would be useful (breaks protocol)
- while size is possibly useful, breaks protocol
- anthony wants a self-descriptive protocol if we break (like ASN.1)
- but all moot until everything is converted to vmstate
- need to consider specifying a new protocol

KVM/qemu patches
- patch rate is high, documentation is low, review is low
- patches need to include better descriptions and documentation
- will slow down patch writers
- will make it easier for patch reviewers

QMP
- spec review
- migration events
- introduce migration connected event
- migration completed/done event (more contentious)
- no data, just indication that it's done
- run query migrate to get status
- 0.14 proper async
- (-rc is coming next Monday)
- important to start simple, fix as go...
- no good indication of completion in general across monitor
- includes feedback from guest (pci remove device, shutdown, balloon, etc...)
- async is the consistent issue
- libvirt should not use QMP in 0.13
- need to declare QMP Unstable 0.13 (still need spec review)