Re: [libvirt] [PATCHv4 0/3] Add support for file memorybacking

-----Original Message----- From: Michal Privoznik [mailto:mprivozn@redhat.com] Sent: Saturday, January 28, 2017 3:03 PM To: Safka, JaroslavX <jaroslavx.safka(a)intel.com>; libvir-list(a)redhat.com Cc: Mooney, Sean K <sean.k.mooney(a)intel.com>; Ptacek, MichalX <michalx.ptacek(a)intel.com>; Daniel P. Berrange <berrange(a)redhat.com&gt; Subject: Re: [libvirt] [PATCHv4 0/3] Add support for file memorybacking On 13.12.2016 13:12, Jaroslav Safka wrote: > Hi, > we would like to introduce 3 new elements source,access and allocation in memoryBacking element. > For now it was made for numa topology. > > <memoryBacking> > <source type="file|anonymous"/> > <access mode="shared|private"/> > <allocation mode="immediate|ondemand"/> </memoryBacking> > > If allocation is immediate then -mem-prealloc should be added to the qemu commanline. > If source is file then > -object memory-backend-file,id=mem,size=1024M,mem-path=*lib dir path* > -numa node,memdev=mem Will be added to the qemu commandline > > If access is shared then the "share=on" parameter will be added to the memory-backend-file e.g. > -object > memory-backend-file,id=mem,size=1024M,mem-path=/var/lib/libvirt/qemu,s > hare=on > > The access mode can be overriden by specifying token memAccess in numa cell. > > The test cpu-numa-memshared was removed, because behaviour was changed > and is not needed anymore I beg to disagree. What if you don't have any <memoryBacking/>?

I like these patches, but I'm not certainly sure about: a) domain XML (in the past we used to require an ACK on schema change from one of the Dans) b) the location for qemu to create its mmaped files (patch 3/3). cfg->libDir looks very suspicious.

I have the patches applied locally with all the changes I've pointed out applied. If we have answers to both of the questions, I can push these. Michal