From: Vladimir Sementsov-Ogievskiy Date: Wed, 10 Feb 2016 08:49:26 +0000 (+0300) Subject: balloon: Use only 'pc-dimm' type dimm for ballooning X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2b75f848238651ef1bb407f66fa38d68775782bf;p=qemu.git balloon: Use only 'pc-dimm' type dimm for ballooning For now there are only two dimm's: pc-dimm and nvdimm. This patch is actually needed to disable ballooning on nvdimm. But, to avoid future bugs, instead of disallowing nvdimm, we allow only pc-dimm. So, if someone adds new dimm which should be balloon-able, then this ability should be explicitly specified here. Why ballooning for nvdimm should be disabled for now: 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 Signed-off-by: Denis V. Lunev Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index 388e87336a..e9c30e9615 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -305,15 +305,33 @@ static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) memcpy(config_data, &config, sizeof(struct virtio_balloon_config)); } +static int build_dimm_list(Object *obj, void *opaque) +{ + GSList **list = opaque; + + if (object_dynamic_cast(obj, TYPE_PC_DIMM)) { + DeviceState *dev = DEVICE(obj); + if (dev->realized) { /* only realized DIMMs matter */ + *list = g_slist_prepend(*list, dev); + } + } + + object_child_foreach(obj, build_dimm_list, opaque); + return 0; +} + static ram_addr_t get_current_ram_size(void) { GSList *list = NULL, *item; ram_addr_t size = ram_size; - pc_dimm_build_list(qdev_get_machine(), &list); + build_dimm_list(qdev_get_machine(), &list); for (item = list; item; item = g_slist_next(item)) { Object *obj = OBJECT(item->data); - size += object_property_get_int(obj, PC_DIMM_SIZE_PROP, &error_abort); + if (!strcmp(object_get_typename(obj), TYPE_PC_DIMM)) { + size += object_property_get_int(obj, PC_DIMM_SIZE_PROP, + &error_abort); + } } g_slist_free(list);