[libvirt] [PATCH 4/8] Add 'period' for Memballoon statistics gathering capability

[John Ferlan]

Add a period in seconds to allow/enable statistics gathering from the
Balloon driver for 'virsh dommemstat <domain>'.
---
 docs/schemas/domaincommon.rng |  7 +++++++
 src/conf/domain_conf.c        | 27 +++++++++++++++++++++++----
 src/conf/domain_conf.h        |  1 +
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index cf82878..53e707c 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -2915,6 +2915,13 @@
       <optional>
         <ref name="address"/>
       </optional>
+      <optional>
+        <element name="stats">
+          <attribute name="period">
+            <ref name="positiveInteger"/>
+          </attribute>
+        </element>
+      </optional>
     </element>
   </define>
   <define name="parallel">
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 011de71..cd7dbee 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -8571,10 +8571,12 @@ error:
 
 static virDomainMemballoonDefPtr
 virDomainMemballoonDefParseXML(const xmlNodePtr node,
+                               xmlXPathContextPtr ctxt,
                                unsigned int flags)
 {
     char *model;
     virDomainMemballoonDefPtr def;
+    xmlNodePtr save = ctxt->node;
 
     if (VIR_ALLOC(def) < 0) {
         virReportOOMError();
@@ -8587,18 +8589,24 @@ virDomainMemballoonDefParseXML(const xmlNodePtr node,
                        _("balloon memory must contain model name"));
         goto error;
     }
+
     if ((def->model = virDomainMemballoonModelTypeFromString(model)) < 0) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
                        _("unknown memory balloon model '%s'"), model);
         goto error;
     }
 
+    ctxt->node = node;
+    if (virXPathInt("string(./stats/@period)", ctxt, &def->period) < 0)
+        def->period = 0;
+
     if (virDomainDeviceInfoParseXML(node, NULL, &def->info, flags) < 0)
         goto error;
 
 cleanup:
     VIR_FREE(model);
 
+    ctxt->node = save;
     return def;
 
 error:
@@ -11911,7 +11919,7 @@ virDomainDefParseXML(xmlDocPtr xml,
     }
     if (n > 0) {
         virDomainMemballoonDefPtr memballoon =
-            virDomainMemballoonDefParseXML(nodes[0], flags);
+            virDomainMemballoonDefParseXML(nodes[0], ctxt, flags);
         if (!memballoon)
             goto error;
 
@@ -15080,6 +15088,7 @@ virDomainMemballoonDefFormat(virBufferPtr buf,
                              unsigned int flags)
 {
     const char *model = virDomainMemballoonModelTypeToString(def->model);
+    bool noopts = true;
 
     if (!model) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
@@ -15093,11 +15102,21 @@ virDomainMemballoonDefFormat(virBufferPtr buf,
         virBufferAddLit(buf, ">\n");
         if (virDomainDeviceInfoFormat(buf, &def->info, flags) < 0)
             return -1;
-        virBufferAddLit(buf, "    </memballoon>\n");
-    } else {
-        virBufferAddLit(buf, "/>\n");
+        noopts = false;
     }
 
+    if (def->period) {
+        if (noopts)
+            virBufferAddLit(buf, ">\n");
+        virBufferAsprintf(buf, "      <stats period='%d'/>\n", def->period);
+        noopts = false;
+    }
+
+    if (noopts)
+        virBufferAddLit(buf, "/>\n");
+    else
+        virBufferAddLit(buf, "    </memballoon>\n");
+
     return 0;
 }
 
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 3817e37..405903f 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -1527,6 +1527,7 @@ enum {
 struct _virDomainMemballoonDef {
     int model;
     virDomainDeviceInfo info;
+    int period; /* seconds between collections */
 };
 
 struct _virDomainNVRAMDef {
-- 
1.8.1.4