Re: [Qemu-devel] [PATCH 3/3] balloon: don't use NVDIMM for ballooning

[Eric Blake <eblake@redhat.com>]

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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 <vsementsov@virtuozzo.com>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> CC: Stefan Hajnoczi <stefanha@redhat.com>
> CC: Xiao Guangrong <guangrong.xiao@linux.intel.com>
> CC: "Michael S. Tsirkin" <mst@redhat.com>
> CC: Igor Mammedov <imammedo@redhat.com>
> CC: Eric Blake <eblake@redhat.com>
> CC: Markus Armbruster <armbru@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().

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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