On Wed, 03 Feb 2016 16:42:21 +0100
Markus Armbruster <arm...@redhat.com> wrote:
> Eric Blake <ebl...@redhat.com> writes:
>
> > On 01/27/2016 11:51 PM, Vladimir Sementsov-Ogievskiy wrote:
> >> NVDIMM for now is planned to use as a backing store for DAX filesystem
> >> in the guest and thus this memory is excluded from guest memory
> >> management and LRUs.
> >>
> >> In this case libvirt running QEMU along with configured balloon almost
> >> immediately inflates balloon and effectively kill the guest as
> >> qemu counts nvdimm as part of the ram.
> >>
> >> Counting dimm devices as part of the ram for ballooning was started from
> >> commit 463756d03:
> >> virtio-balloon: Fix balloon not working correctly when hotplug memory
> >>
> >> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
> >> Signed-off-by: Denis V. Lunev <d...@openvz.org>
> >> CC: Stefan Hajnoczi <stefa...@redhat.com>
> >> CC: Xiao Guangrong <guangrong.x...@linux.intel.com>
> >> CC: "Michael S. Tsirkin" <m...@redhat.com>
> >> CC: Igor Mammedov <imamm...@redhat.com>
> >> CC: Eric Blake <ebl...@redhat.com>
> >> CC: Markus Armbruster <arm...@redhat.com>
> >> ---
> >
> >> @@ -308,7 +309,9 @@ static ram_addr_t get_current_ram_size(void)
> >> if (value) {
> >> switch (value->type) {
> >> case MEMORY_DEVICE_INFO_KIND_DIMM:
> >> - size += value->u.dimm->size;
> >> + if (strcmp(value->u.dimm->type, TYPE_NVDIMM)) {
> >
> > If you fix 2/3 to use a QAPI enum, then this will be an integer compare
> > instead of a strcmp().
>
> Another option is to add a flag to the subtypes of TYPE_PC_DIMM, set it
> for the subtypes that should be counted here, and accumulate the sizes
> of devices where the flag is set. Requires iterating directly over the
> devices here (like qmp_pc_dimm_device_list() does under the hood) rather
> than the MemoryDeviceInfoList returned by qmp_pc_dimm_device_list(),
I'd rather not add flag to TYPE_PC_DIMM state/class as its purely balloon
qemu/guest driver limit and not related to [pc-|nv]in general.
Lets whitelist balloon supported type here.
