On Fri, Dec 18, 2009 at 01:17:03PM -0500, Adam Litke wrote:

Daniel, this should be ready for you to merge...

Okidoc, done ! There was a bit of tweaking since this conflicted with another new API, but this was eay to solve. I double checked the new src/remote/remote_protocol.x description and that looks fine, I think the only thing missing is a description of the new virsh command in tools/virsh.pod and I think this will be complete. Ah and other bindings need to be updated to export the new function, but that's seaparate. thanks ! Daniel

Changes since V3: * Fixed remote_protocol.x so rpcgen generates the right code * Updated stat constants and names in python api * Incorporate flags into the rpc wire format

Changes since V2: * Ported to GIT HEAD for easier merging :) * Amounts of memory are now reported in kilobytes * Added flags parameter to API (currently unused) * Moved to less awkward xdr wire format for remote driver * Stats 'Free' and 'Total' renamed to 'Unused' and 'Available' * Various small fixups: constant names, data types, etc

Changes since V1: * New system for maintaining ABI compatibility and API extensibility: Rather than passing around a fixed-size stats structure, work with arrays of stats. An enum of known statistic tags (SWAP_IN, SWAP_OUT, TOTAL_MEM, etc) is defined. A stat is defined as a tag/value pair. When making a call to the API, the caller provides an array of stats and the size of the array. That array is filled with up to the requested number of stats (depending on hypervisor and guest support). The number of stats provided is returned.

* Miscellaneous changes: Changed the API function from virDomainMemStats to virDomainMemoryStats Added documentation for each memory stat

--

When using ballooning to manage overcommitted memory on a host, a system for guests to communicate their memory usage to the host can provide information that will minimize the impact of ballooning on the guests while maximizing efficient use of host memory.

The design of such a communication channel was recently added to version 0.8.2 of the VirtIO Spec (See Appendix G): - http://ozlabs.org/~rusty/virtio-spec/virtio-spec-0.8.2.pdf

Host-side and guest-side implementations have been accepted for inclusion in their respective projects: - Guest: http://lkml.org/lkml/2009/11/30/274 - Host: http://lists.gnu.org/archive/html/qemu-devel/2009-12/msg00380.html

The following patch series implements a new libvirt interface to expose these memory statistics. Thank you for your review and comments.

[PATCH 1/6] domMemoryStats: Add domainMemoryStats method to struct _virDriver [PATCH 2/6] domMemoryStats: Add public symbol to libvirt API [PATCH 3/6] qemu-driver: Enable domainMemStats in the qemu driver [PATCH 4/6] remote-driver: Add domainMemoryStats support [PATCH 5/6] virsh: Enable virDomainMemoryStats as a new command [PATCH 6/6] python: Add python bindings for virDomainMemoryStats

-- Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/ daniel@veillard.com | Rpmfind RPM search engine http://rpmfind.net/ http://veillard.com/ | virtualization library http://libvirt.org/