On Tue, Dec 01, 2020 at 11:42:18 +0300, Andrey Gruzdev wrote: > On 01.12.2020 10:08, Peter Krempa wrote: > > On Thu, Nov 26, 2020 at 18:17:28 +0300, Andrey Gruzdev via wrote: > > > This patch series is a kind of 'rethinking' of Denis Plotnikov's ideas > > > he's
[...] > > Note that in cases when qemu can't guarantee that the > > background_snapshot feature will work it should not advertise it. We > > need a way to check whether it's possible to use it, so we can replace > > the existing --live flag with it rather than adding a new one and > > shifting the problem of checking whether the feature works to the user. > > > > Hi, > > May be you are using hugetlbfs as memory backend? Not exactly hugepages, but I had: <memoryBacking> <access mode='shared'/> </memoryBacking> which resulted into the following commandline to instantiate memory: -object memory-backend-file,id=pc.ram,mem-path=/var/lib/libvirt/qemu/ram/6-upstream-bj/pc.ram,share=yes,size=33554432000,host-nodes=0,policy=bind \ When I've removed it I got: -object memory-backend-ram,id=pc.ram,size=33554432000,host-nodes=0,policy=bind \ And the migration didn't fail in my quick test. I'll have a more detailed look later, thanks for the pointer. > I totally agree that we need somehow check that kernel and VM memory backend > support the feature before one can enable the capability. > Need to think about that.. Definitely. Also note that memory backed by memory-backend-file will be more and more common, for cases such as virtiofs DAX sharing and similar.