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Re: [Qemu-devel] [PATCH v2 1/1] nvdimm: disable balloon
From: |
Igor Mammedov |
Subject: |
Re: [Qemu-devel] [PATCH v2 1/1] nvdimm: disable balloon |
Date: |
Tue, 26 Jan 2016 11:38:30 +0100 |
On Mon, 25 Jan 2016 19:50:31 +0300
"Denis V. Lunev" <address@hidden> wrote:
> From: Vladimir Sementsov-Ogievskiy <address@hidden>
>
> 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.
Isn't issue in ballooning impl. and not of pc-dimm/nvdimm,
so make ballooning code to distinguish between kinds of memory
rather than adding not related fields to PCDIMMDeviceClass
why don't just move get_current_ram_size() into the sole user
virtio-balloon.c and ignore NVDIMMs when counting ram in
get_current_ram_size(),
that would be much less intrusive patch.
>
> 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 <address@hidden>
> Signed-off-by: Denis V. Lunev <address@hidden>
> CC: Stefan Hajnoczi <address@hidden>
> CC: Xiao Guangrong <address@hidden>
> CC: "Michael S. Tsirkin" <address@hidden>
> CC: Igor Mammedov <address@hidden>
> CC: Eric Blake <address@hidden>
> CC: Markus Armbruster <address@hidden>
> ---
> v2:
> - some rewordings, thanks to Eric Blake
>
> hw/mem/nvdimm.c | 4 ++++
> hw/mem/pc-dimm.c | 7 ++++++-
> include/hw/mem/pc-dimm.h | 1 +
> qapi-schema.json | 5 ++++-
> 4 files changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/hw/mem/nvdimm.c b/hw/mem/nvdimm.c
> index 4fd397f..4f4d29a 100644
> --- a/hw/mem/nvdimm.c
> +++ b/hw/mem/nvdimm.c
> @@ -27,9 +27,13 @@
> static void nvdimm_class_init(ObjectClass *oc, void *data)
> {
> DeviceClass *dc = DEVICE_CLASS(oc);
> + PCDIMMDeviceClass *ddc = PC_DIMM_CLASS(oc);
>
> /* nvdimm hotplug has not been supported yet. */
> dc->hotpluggable = false;
> +
> + /* ballooning is not supported */
> + ddc->in_ram = false;
> }
>
> static TypeInfo nvdimm_info = {
> diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c
> index d5cdab2..e0f869d 100644
> --- a/hw/mem/pc-dimm.c
> +++ b/hw/mem/pc-dimm.c
> @@ -164,6 +164,7 @@ int qmp_pc_dimm_device_list(Object *obj, void *opaque)
> MemoryDeviceInfo *info = g_new0(MemoryDeviceInfo, 1);
> PCDIMMDeviceInfo *di = g_new0(PCDIMMDeviceInfo, 1);
> DeviceClass *dc = DEVICE_GET_CLASS(obj);
> + PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(obj);
> PCDIMMDevice *dimm = PC_DIMM(obj);
>
> if (dev->id) {
> @@ -172,6 +173,7 @@ int qmp_pc_dimm_device_list(Object *obj, void *opaque)
> }
> di->hotplugged = dev->hotplugged;
> di->hotpluggable = dc->hotpluggable;
> + di->in_ram = ddc->in_ram;
> di->addr = dimm->addr;
> di->slot = dimm->slot;
> di->node = dimm->node;
> @@ -205,7 +207,9 @@ 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 (value->u.dimm->in_ram) {
> + size += value->u.dimm->size;
> + }
> break;
> default:
> break;
> @@ -444,6 +448,7 @@ static void pc_dimm_class_init(ObjectClass *oc, void
> *data)
> dc->props = pc_dimm_properties;
> dc->desc = "DIMM memory module";
>
> + ddc->in_ram = true;
> ddc->get_memory_region = pc_dimm_get_memory_region;
> }
>
> diff --git a/include/hw/mem/pc-dimm.h b/include/hw/mem/pc-dimm.h
> index d83bf30..3bcb505 100644
> --- a/include/hw/mem/pc-dimm.h
> +++ b/include/hw/mem/pc-dimm.h
> @@ -65,6 +65,7 @@ typedef struct PCDIMMDevice {
> typedef struct PCDIMMDeviceClass {
> /* private */
> DeviceClass parent_class;
> + bool in_ram;
>
> /* public */
> MemoryRegion *(*get_memory_region)(PCDIMMDevice *dimm);
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 2e960db..3cafa2b 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -3922,6 +3922,8 @@
> #
> # @hotpluggable: true if device if could be added/removed while machine is
> running
> #
> +# @in-ram: true if device is counted in current ram size (since 2.6)
> +#
> # Since: 2.1
> ##
> { 'struct': 'PCDIMMDeviceInfo',
> @@ -3932,7 +3934,8 @@
> 'node': 'int',
> 'memdev': 'str',
> 'hotplugged': 'bool',
> - 'hotpluggable': 'bool'
> + 'hotpluggable': 'bool',
> + 'in-ram': 'bool'
> }
> }
>