[Qemu-devel] [PATCH v3 0/2] nvdimm: disable balloon

[Qemu-devel] [PATCH v3 0/2] nvdimm: disable balloon

[Denis V. Lunev]

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.

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>

v3:
- do not use additional class variable

Vladimir Sementsov-Ogievskiy (2):
  move get_current_ram_size to virtio-balloon.c
  nvdimm: disable balloon

 hw/mem/pc-dimm.c                | 28 ++--------------------------
 hw/virtio/virtio-balloon.c      | 28 ++++++++++++++++++++++++++++
 include/exec/cpu-common.h       |  1 -
 qapi-schema.json                |  5 ++++-
 stubs/qmp_pc_dimm_device_list.c |  5 -----
 5 files changed, 34 insertions(+), 33 deletions(-)

-- 
2.5.0

[Qemu-devel] [PATCH 1/2] move get_current_ram_size to virtio-balloon.c

[Denis V. Lunev]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

get_current_ram_size() is used only in virtio-balloon.c
This patch moves it into virtio-balloon and make it static, to allow
some balloon-specific tuning.

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>
---
 hw/mem/pc-dimm.c                | 26 --------------------------
 hw/virtio/virtio-balloon.c      | 26 ++++++++++++++++++++++++++
 include/exec/cpu-common.h       |  1 -
 stubs/qmp_pc_dimm_device_list.c |  5 -----
 4 files changed, 26 insertions(+), 32 deletions(-)

diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c
index d5cdab2..4f30950 100644
--- a/hw/mem/pc-dimm.c
+++ b/hw/mem/pc-dimm.c
@@ -191,32 +191,6 @@ int qmp_pc_dimm_device_list(Object *obj, void *opaque)
     return 0;
 }
 
-ram_addr_t get_current_ram_size(void)
-{
-    MemoryDeviceInfoList *info_list = NULL;
-    MemoryDeviceInfoList **prev = &info_list;
-    MemoryDeviceInfoList *info;
-    ram_addr_t size = ram_size;
-
-    qmp_pc_dimm_device_list(qdev_get_machine(), &prev);
-    for (info = info_list; info; info = info->next) {
-        MemoryDeviceInfo *value = info->value;
-
-        if (value) {
-            switch (value->type) {
-            case MEMORY_DEVICE_INFO_KIND_DIMM:
-                size += value->u.dimm->size;
-                break;
-            default:
-                break;
-            }
-        }
-    }
-    qapi_free_MemoryDeviceInfoList(info_list);
-
-    return size;
-}
-
 static int pc_dimm_slot2bitmap(Object *obj, void *opaque)
 {
     unsigned long *bitmap = opaque;
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 9671635..6a4c4d2 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -294,6 +294,32 @@ static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
     memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
 }
 
+static ram_addr_t get_current_ram_size(void)
+{
+    MemoryDeviceInfoList *info_list = NULL;
+    MemoryDeviceInfoList **prev = &info_list;
+    MemoryDeviceInfoList *info;
+    ram_addr_t size = ram_size;
+
+    qmp_pc_dimm_device_list(qdev_get_machine(), &prev);
+    for (info = info_list; info; info = info->next) {
+        MemoryDeviceInfo *value = info->value;
+
+        if (value) {
+            switch (value->type) {
+            case MEMORY_DEVICE_INFO_KIND_DIMM:
+                size += value->u.dimm->size;
+                break;
+            default:
+                break;
+            }
+        }
+    }
+    qapi_free_MemoryDeviceInfoList(info_list);
+
+    return size;
+}
+
 static void virtio_balloon_set_config(VirtIODevice *vdev,
                                       const uint8_t *config_data)
 {
diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index 85aa403..a0ad2ac 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -54,7 +54,6 @@ typedef uintptr_t ram_addr_t;
 #endif
 
 extern ram_addr_t ram_size;
-ram_addr_t get_current_ram_size(void);
 
 /* memory API */
 
diff --git a/stubs/qmp_pc_dimm_device_list.c b/stubs/qmp_pc_dimm_device_list.c
index b584bd8..5cb220c 100644
--- a/stubs/qmp_pc_dimm_device_list.c
+++ b/stubs/qmp_pc_dimm_device_list.c
@@ -5,8 +5,3 @@ int qmp_pc_dimm_device_list(Object *obj, void *opaque)
 {
    return 0;
 }
-
-ram_addr_t get_current_ram_size(void)
-{
-    return ram_size;
-}
-- 
2.5.0

Re: [Qemu-devel] [PATCH 1/2] move get_current_ram_size to virtio-balloon.c

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 1125 bytes --]

On 01/27/2016 06:24 AM, Denis V. Lunev wrote:
> From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> 
> get_current_ram_size() is used only in virtio-balloon.c
> This patch moves it into virtio-balloon and make it static, to allow
> some balloon-specific tuning.
> 
> 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>
> ---
>  hw/mem/pc-dimm.c                | 26 --------------------------
>  hw/virtio/virtio-balloon.c      | 26 ++++++++++++++++++++++++++
>  include/exec/cpu-common.h       |  1 -
>  stubs/qmp_pc_dimm_device_list.c |  5 -----
>  4 files changed, 26 insertions(+), 32 deletions(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

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


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 604 bytes --]

[Qemu-devel] [PATCH 2/2] nvdimm: disable balloon

[Denis V. Lunev]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

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>
---
 hw/mem/pc-dimm.c           | 2 ++
 hw/virtio/virtio-balloon.c | 4 +++-
 qapi-schema.json           | 5 ++++-
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c
index 4f30950..2ff9f95 100644
--- a/hw/mem/pc-dimm.c
+++ b/hw/mem/pc-dimm.c
@@ -19,6 +19,7 @@
  */
 
 #include "hw/mem/pc-dimm.h"
+#include "hw/mem/nvdimm.h"
 #include "qemu/config-file.h"
 #include "qapi/visitor.h"
 #include "qemu/range.h"
@@ -178,6 +179,7 @@ int qmp_pc_dimm_device_list(Object *obj, void *opaque)
             di->size = object_property_get_int(OBJECT(dimm), PC_DIMM_SIZE_PROP,
                                                NULL);
             di->memdev = object_get_canonical_path(OBJECT(dimm->hostmem));
+            di->balloonable = (object_dynamic_cast(obj, TYPE_NVDIMM) == NULL);
 
             info->u.dimm = di;
             elem->value = info;
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 6a4c4d2..0a3de75 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -308,7 +308,9 @@ 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 (value->u.dimm->balloonable) {
+                    size += value->u.dimm->size;
+                }
                 break;
             default:
                 break;
diff --git a/qapi-schema.json b/qapi-schema.json
index 8d04897..5934f81 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -3924,6 +3924,8 @@
 #
 # @hotpluggable: true if device if could be added/removed while machine is running
 #
+# @balloonable: true if device take part in ballooning (since 2.6)
+#
 # Since: 2.1
 ##
 { 'struct': 'PCDIMMDeviceInfo',
@@ -3934,7 +3936,8 @@
             'node': 'int',
             'memdev': 'str',
             'hotplugged': 'bool',
-            'hotpluggable': 'bool'
+            'hotpluggable': 'bool',
+            'balloonable': 'bool'
           }
 }
 
-- 
2.5.0

Re: [Qemu-devel] [PATCH 2/2] nvdimm: disable balloon

[Igor Mammedov]

On Wed, 27 Jan 2016 16:24:29 +0300
"Denis V. Lunev" <den@openvz.org> wrote:

suggest to change subj to: don't use NVDIMM for balooning

> From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> 
> 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>
> ---
>  hw/mem/pc-dimm.c           | 2 ++
>  hw/virtio/virtio-balloon.c | 4 +++-
>  qapi-schema.json           | 5 ++++-
>  3 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c
> index 4f30950..2ff9f95 100644
> --- a/hw/mem/pc-dimm.c
> +++ b/hw/mem/pc-dimm.c
> @@ -19,6 +19,7 @@
>   */
>  
>  #include "hw/mem/pc-dimm.h"
> +#include "hw/mem/nvdimm.h"
>  #include "qemu/config-file.h"
>  #include "qapi/visitor.h"
>  #include "qemu/range.h"
> @@ -178,6 +179,7 @@ int qmp_pc_dimm_device_list(Object *obj, void *opaque)
>              di->size = object_property_get_int(OBJECT(dimm), PC_DIMM_SIZE_PROP,
>                                                 NULL);
>              di->memdev = object_get_canonical_path(OBJECT(dimm->hostmem));
> +            di->balloonable = (object_dynamic_cast(obj, TYPE_NVDIMM) == NULL);
I don't think that balloonable is property of DIMM and that it should be
displayed by MemoryDeviceInfo.
I'd drop this + the last hunk and put check directly into get_current_ram_size()
in this patch.
And another path on top that adds 'type' to PCDIMMDeviceInfo and shows
it in hmp_info_memory_devices() so that management tools/users would be
able to distinguish entries.

>  
>              info->u.dimm = di;
>              elem->value = info;
> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
> index 6a4c4d2..0a3de75 100644
> --- a/hw/virtio/virtio-balloon.c
> +++ b/hw/virtio/virtio-balloon.c
> @@ -308,7 +308,9 @@ 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 (value->u.dimm->balloonable) {
> +                    size += value->u.dimm->size;
> +                }
>                  break;
>              default:
>                  break;
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 8d04897..5934f81 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -3924,6 +3924,8 @@
>  #
>  # @hotpluggable: true if device if could be added/removed while machine is running
>  #
> +# @balloonable: true if device take part in ballooning (since 2.6)
> +#
>  # Since: 2.1
>  ##
>  { 'struct': 'PCDIMMDeviceInfo',
> @@ -3934,7 +3936,8 @@
>              'node': 'int',
>              'memdev': 'str',
>              'hotplugged': 'bool',
> -            'hotpluggable': 'bool'
> +            'hotpluggable': 'bool',
> +            'balloonable': 'bool'
>            }
>  }
>  

Re: [Qemu-devel] [PATCH 2/2] nvdimm: disable balloon

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 2451 bytes --]

On 01/27/2016 06:24 AM, Denis V. Lunev wrote:
> From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> 
> 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.

Intentional mid-line break?

> 
> 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>
> ---
>  hw/mem/pc-dimm.c           | 2 ++
>  hw/virtio/virtio-balloon.c | 4 +++-
>  qapi-schema.json           | 5 ++++-
>  3 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c
> index 4f30950..2ff9f95 100644
> --- a/hw/mem/pc-dimm.c
> +++ b/hw/mem/pc-dimm.c
> @@ -19,6 +19,7 @@
>   */
>  
>  #include "hw/mem/pc-dimm.h"
> +#include "hw/mem/nvdimm.h"
>  #include "qemu/config-file.h"
>  #include "qapi/visitor.h"
>  #include "qemu/range.h"
> @@ -178,6 +179,7 @@ int qmp_pc_dimm_device_list(Object *obj, void *opaque)
>              di->size = object_property_get_int(OBJECT(dimm), PC_DIMM_SIZE_PROP,
>                                                 NULL);
>              di->memdev = object_get_canonical_path(OBJECT(dimm->hostmem));
> +            di->balloonable = (object_dynamic_cast(obj, TYPE_NVDIMM) == NULL);

The outer () seem spurious to me; I might have shortened this to:

di->balloonable = !object_dynamic_cast(obj, TYPE_NVDIMM);


> +++ b/qapi-schema.json
> @@ -3924,6 +3924,8 @@
>  #
>  # @hotpluggable: true if device if could be added/removed while machine is running
>  #
> +# @balloonable: true if device take part in ballooning (since 2.6)

s/take/takes/

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


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 604 bytes --]