Re: [libvirt] [PATCH 0/2] memdev device: add share argument for type=file

On Fri, Jun 27, 2014 at 10:53:10PM +0200, Michele Paolino wrote: >This patch enables the possibility to run a qemu virtual machine with the >share option for the memory-backend-file. The xml description looks like: > ><memdev type='file' share='on'> > <name>ram0</name> > <source mem-path='/hugetlbfs'/> > <capacity unit='MiB'>1024</capacity> ></memdev> > >This work is based on the previous work of Chen Fan[1]. >We are aware of the existing conflict with the previous numa patches[2]. >We are sharing this because it is a dependency for some use cases of the >qemu vhost-user support(e.g. snabbswitch). > There is one important thing left out. What qemu uses as a memdev should not be exposed as such (a device) in the XML, that way the definition makes sense only for people aware of how qemu works, but we are trying to keep the XML as hypervisor-independent as possible. Of course only where applicable, many places must have hypervisor-dependent structures, but I don't think memory device is one of these exceptions. All the options that qemu aspose as memdev options should be abstracted in the XML. For example3, we already have an element in the XML that says "use hugepages as a backing for memory" and that element should be used for that. I just skimmed the patches a bit, but it looks like none of the series works with that information or changes the behaviour based on that.