Re: [libvirt] [PATCH V3 1/2] Intorduce file descriptor set for QEMU domains

On 02/07/2013 12:58 PM, Daniel P. Berrange wrote: >On Thu, Feb 07, 2013 at 12:56:45PM -0500, Stefan Berger wrote: >>On 02/07/2013 10:12 AM, Daniel P. Berrange wrote: >>>On Mon, Feb 04, 2013 at 07:12:37PM -0500, Stefan Berger wrote: >>>>Create field in virDomainDeviceInfo structure to hold >>>>file descriptor set the device is associated with. Have >>>>the number written into the Device Info XML and parsed >>>>from the XML. >>>>Remember the next-toy use file descriptor set in the QEMU >>>>private domain structure. >>>>Upon libvirt restart determine the maximum file descriptor >>>>set used in the Device Info XML and remember the >>>>next-to-use file descriptor set in the QEMU private domain >>>>structure. >>>> >>>>Upon termination of a domain, reset the next-to-use file >>>>descriptor set to its initial value '1'. >>>> >>>>Stefan Berger <stefanb(a)linux.vnet.ibm.com&gt; >>>> >>>>--- >>>> src/conf/capabilities.h | 5 ++++- >>>> src/conf/domain_conf.c | 20 +++++++++++++++++--- >>>> src/conf/domain_conf.h | 1 + >>>> src/lxc/lxc_domain.c | 3 ++- >>>> src/qemu/qemu_domain.c | 23 ++++++++++++++++++++++- >>>> src/qemu/qemu_domain.h | 2 ++ >>>> src/qemu/qemu_process.c | 2 ++ >>>> 7 files changed, 50 insertions(+), 6 deletions(-) >>>I really don't like the fact that we're modifying the virDomainDef >>>structs, which are intended to hold static config description, to >>>also hold QEMU specific dynamic state. We did this in the past >>>before we had the per-driver 'privateData' associated with >>>virDomainObjPtr instances. >>In these patches we are storing the fdset that's in use by a >>particular device in the virDomainDeviceInfo structure and are >>persisting that fdset number next to the device's alias into XML >>written into /var/run/libvirt/qemu to be able to restore it upon >>libvirt restart. Now we would either need a similar per-device >>structure in parallel to those virDomainDeviceInfo structures or >>connect a QEMU private data structure to that virDomainDeviceInfo >>structure for storing the dynamic data and to keep reference back to >>the device. Not sure what's the best path ... >Just have a hashtable mapping device alias names -> fd set numbers >in the qemuDomainObjPrivatePtr, and write that out in the QEMU >private XML. There's no need to directly mirror the structs. > you agree to this XML ? <fdsets> <entry alias='ide0-0-0' fdset='1'/> <entry alias='serial0' fdset='2'/> <entry alias='serial1' fdset='3'/> </fdsets>