[PATCH 1/1] Optional free-page-reporting can be enabled/disabled for memballon device of model 'virtio'.
Nico Pache
npache at redhat.com
Fri Oct 2 15:59:43 UTC 2020
xml:
<devices>
<memballoon model='virtio' free-page-reporting='on'/>
</devices>
qemu:
qemu -device virtio-balloon-pci,...,free-page-reporting=on
This kernel feature allows for more stable and resource friendly systems.
Signed-off-by: Nico Pache <npache at redhat.com>
---
docs/formatdomain.rst | 6 ++++++
docs/schemas/domaincommon.rng | 5 +++++
src/conf/domain_conf.c | 21 +++++++++++++++++++
src/conf/domain_conf.h | 1 +
src/qemu/qemu_capabilities.c | 4 +++-
src/qemu/qemu_capabilities.h | 1 +
src/qemu/qemu_command.c | 5 +++++
src/qemu/qemu_validate.c | 7 +++++++
.../caps_5.1.0.x86_64.xml | 1 +
.../caps_5.2.0.x86_64.xml | 1 +
10 files changed, 51 insertions(+), 1 deletion(-)
diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index f3cf9e1fb3..f4c7765f5f 100644
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -6755,6 +6755,12 @@ Example: manually added device with static PCI slot 2 requested
release some memory at the last moment before a guest's process get killed by
Out of Memory killer. :since:`Since 1.3.1, QEMU and KVM only`
+``free-page-reporting``
+ The optional ``free-page-reporting`` attribute allows to enable/disable
+ ("on"/"off", respectively) the ability of the QEMU virtio memory balloon to
+ return unused pages back to the hypervisor to be used by other guests or
+ processes. :since:`Since 5.1, QEMU and KVM only`
+
``period``
The optional ``period`` allows the QEMU virtio memory balloon driver to
provide statistics through the ``virsh dommemstat [domain]``
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 4b7e460148..4c32b3555f 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -4539,6 +4539,11 @@
<ref name="virOnOff"/>
</attribute>
</optional>
+ <optional>
+ <attribute name="free-page-reporting">
+ <ref name="virOnOff"/>
+ </attribute>
+ </optional>
<interleave>
<optional>
<ref name="alias"/>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index b80d7c7c6c..f4b8e8d8c3 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -15384,6 +15384,7 @@ virDomainMemballoonDefParseXML(virDomainXMLOptionPtr xmlopt,
VIR_XPATH_NODE_AUTORESTORE(ctxt)
unsigned int period = 0;
g_autofree char *model = NULL;
+ g_autofree char *freepage_reporting = NULL;
g_autofree char *deflate = NULL;
if (VIR_ALLOC(def) < 0)
@@ -15409,6 +15410,13 @@ virDomainMemballoonDefParseXML(virDomainXMLOptionPtr xmlopt,
goto error;
}
+ if ((freepage_reporting = virXMLPropString(node, "free-page-reporting")) &&
+ (def->free_page_reporting = virTristateSwitchTypeFromString(freepage_reporting)) <= 0) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("invalid free-page-reporting attribute value '%s'"), freepage_reporting);
+ goto error;
+ }
+
ctxt->node = node;
if (virXPathUInt("string(./stats/@period)", ctxt, &period) < -1) {
virReportError(VIR_ERR_XML_ERROR, "%s",
@@ -23630,6 +23638,15 @@ virDomainMemballoonDefCheckABIStability(virDomainMemballoonDefPtr src,
return false;
}
+ if (src->free_page_reporting != dst->free_page_reporting) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("Target balloon free-page-reporting attribute value "
+ "'%s' does not match source '%s'"),
+ virTristateSwitchTypeToString(dst->free_page_reporting),
+ virTristateSwitchTypeToString(src->free_page_reporting));
+ return false;
+ }
+
if (src->virtio && dst->virtio &&
!virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
return false;
@@ -27737,6 +27754,10 @@ virDomainMemballoonDefFormat(virBufferPtr buf,
virBufferAsprintf(&attrBuf, " autodeflate='%s'",
virTristateSwitchTypeToString(def->autodeflate));
+ if (def->free_page_reporting != VIR_TRISTATE_SWITCH_ABSENT)
+ virBufferAsprintf(&attrBuf, " free-page-reporting='%s'",
+ virTristateSwitchTypeToString(def->free_page_reporting));
+
if (def->period)
virBufferAsprintf(&childrenBuf, "<stats period='%i'/>\n", def->period);
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 9a44315519..f5f8baf32c 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -1790,6 +1790,7 @@ struct _virDomainMemballoonDef {
virDomainDeviceInfo info;
int period; /* seconds between collections */
int autodeflate; /* enum virTristateSwitch */
+ int free_page_reporting; /* enum virTristateSwitch */
virDomainVirtioOptionsPtr virtio;
};
diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index 5dcfcd574d..88a2c8aacb 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -600,7 +600,8 @@ VIR_ENUM_IMPL(virQEMUCaps,
/* 380 */
"usb-host.hostdevice",
- );
+ "virtio-balloon-pci.free-page-reporting",
+ );
typedef struct _virQEMUCapsMachineType virQEMUCapsMachineType;
@@ -1344,6 +1345,7 @@ static struct virQEMUCapsDevicePropsFlags virQEMUCapsDevicePropsVirtioBalloon[]
{ "iommu_platform", QEMU_CAPS_VIRTIO_PCI_IOMMU_PLATFORM, NULL },
{ "ats", QEMU_CAPS_VIRTIO_PCI_ATS, NULL },
{ "packed", QEMU_CAPS_VIRTIO_PACKED_QUEUES, NULL },
+ { "free-page-reporting", QEMU_CAPS_VIRTIO_BALLOON_FREE_PAGE_REPORTING, NULL },
};
diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h
index 98d70cfa0e..6f39bf156f 100644
--- a/src/qemu/qemu_capabilities.h
+++ b/src/qemu/qemu_capabilities.h
@@ -580,6 +580,7 @@ typedef enum { /* virQEMUCapsFlags grouping marker for syntax-check */
/* 380 */
QEMU_CAPS_USB_HOST_HOSTDEVICE, /* -device usb-host.hostdevice */
+ QEMU_CAPS_VIRTIO_BALLOON_FREE_PAGE_REPORTING, /*virtio balloon free-page-reporting */
QEMU_CAPS_LAST /* this must always be the last item */
} virQEMUCapsFlags;
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index e9ba81d82f..f80efaf026 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -3830,6 +3830,11 @@ qemuBuildMemballoonCommandLine(virCommandPtr cmd,
virTristateSwitchTypeToString(def->memballoon->autodeflate));
}
+ if (def->memballoon->free_page_reporting != VIR_TRISTATE_SWITCH_ABSENT) {
+ virBufferAsprintf(&buf, ",free-page-reporting=%s",
+ virTristateSwitchTypeToString(def->memballoon->free_page_reporting));
+ }
+
qemuBuildVirtioOptionsStr(&buf, def->memballoon->virtio);
if (qemuCommandAddExtDevice(cmd, &def->memballoon->info) < 0)
diff --git a/src/qemu/qemu_validate.c b/src/qemu/qemu_validate.c
index a212605579..cfeb1e67c4 100644
--- a/src/qemu/qemu_validate.c
+++ b/src/qemu/qemu_validate.c
@@ -3926,6 +3926,13 @@ qemuValidateDomainDeviceDefMemballoon(const virDomainMemballoonDef *memballoon,
return -1;
}
+ if (memballoon->free_page_reporting != VIR_TRISTATE_SWITCH_ABSENT &&
+ !virQEMUCapsGet(qemuCaps, QEMU_CAPS_VIRTIO_BALLOON_FREE_PAGE_REPORTING)) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+ _("free-page-reporting is not supported by this QEMU binary"));
+ return -1;
+ }
+
if (qemuValidateDomainVirtioOptions(memballoon->virtio, qemuCaps) < 0)
return -1;
diff --git a/tests/qemucapabilitiesdata/caps_5.1.0.x86_64.xml b/tests/qemucapabilitiesdata/caps_5.1.0.x86_64.xml
index 987beb965e..1f1615b94b 100644
--- a/tests/qemucapabilitiesdata/caps_5.1.0.x86_64.xml
+++ b/tests/qemucapabilitiesdata/caps_5.1.0.x86_64.xml
@@ -243,6 +243,7 @@
<flag name='numa.hmat'/>
<flag name='blockdev-hostdev-scsi'/>
<flag name='usb-host.hostdevice'/>
+ <flag name='virtio-balloon-pci.free-page-reporting'/>
<version>5001000</version>
<kvmVersion>0</kvmVersion>
<microcodeVersion>43100242</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_5.2.0.x86_64.xml b/tests/qemucapabilitiesdata/caps_5.2.0.x86_64.xml
index 3ee678ef8f..82f9051101 100644
--- a/tests/qemucapabilitiesdata/caps_5.2.0.x86_64.xml
+++ b/tests/qemucapabilitiesdata/caps_5.2.0.x86_64.xml
@@ -243,6 +243,7 @@
<flag name='numa.hmat'/>
<flag name='blockdev-hostdev-scsi'/>
<flag name='usb-host.hostdevice'/>
+ <flag name='virtio-balloon-pci.free-page-reporting'/>
<version>5001050</version>
<kvmVersion>0</kvmVersion>
<microcodeVersion>43100243</microcodeVersion>
--
2.18.4
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