Il 16/07/2013 12:19, Igor Mammedov ha scritto: > On Tue, 16 Jul 2013 08:19:48 +0200 > Paolo Bonzini <pbonz...@redhat.com> wrote: > >> Il 16/07/2013 03:27, Hu Tao ha scritto: >>>> I think it's the same. One "-numa mem" option = one "-device dimm" >>>> option; both define one range. Unused memory ranges may remain if you >>>> stumble upon a unusable range such as the PCI window. For example two >>>> "-numa mem,size=2G" options would allocate memory from 0 to 2G and from >>>> 4 to 6G. >>> >>> So we can drop -dimm if we agree on -numa mem? >> >> Yes, the point of the "-numa mem" proposal was to avoid the concept of a >> "partially initialized device" that you had for DIMMs. > I've though -numa mem was for mapping initial memory to numa nodes. > It seem wrong to use it for representing dimm device and also limiting > possible hotplugged regions to specified at startup ranges.
It's not for DIMM devices, it is for reserving areas of the address space for hot-plugged RAM. DIMM hotplug is done with "device_add dimm" (and you can also use "-numa mem,populated=no,... -device dimm,..." to start a VM with hot-unpluggable memory). > we can leave -numa for initial memory mapping and manage of the mapping > of hotpluggable regions with -device dimm,node=X,size=Y. > > It that case command line -device dimm will provide a fully initialized > dimm device usable at startup (but hot-unplugable) and > (monitor) device_add dimm,,node=X,size=Y > would serve hot-plug case. > > That way arbitrary sized dimm could be hot-pluged without specifying them > at startup, like it's done on bare-metal. But the memory ranges need to be specified at startup in the ACPI tables, and that's what "-numa mem" is for. > In addition command line -device would be used in migration case to describe > already hot-plugged dimms on target. Yep. Paolo
