[libvirt] [PATCH] qemu: expand domain memory statistics with 'last-update' timestamp

[Derbyshev Dmitriy]

From: Derbyshev Dmitry <dderbyshev at virtuozzo.com>

QEMU reports timestamp along with other memory statistics, but this information is not saved into domain statistics.
It could be useful to determine if the data reported is fresh or not.
Balloon statistics are not reported in hrf, so no modifications are made in qemu_monitor_text.c.
---
 include/libvirt/libvirt-domain.h |  6 +++++-
 src/libvirt-domain.c             |  2 ++
 src/qemu/qemu_monitor_json.c     | 21 +++++++++++----------
 tools/virsh-domain-monitor.c     |  2 ++
 4 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
index e1d9a0d..51f9785 100644
--- a/include/libvirt/libvirt-domain.h
+++ b/include/libvirt/libvirt-domain.h
@@ -603,11 +603,15 @@ typedef enum {
      * is in kB */
     VIR_DOMAIN_MEMORY_STAT_RSS             = 7,
 
+
+    /* Timestamp of the last update of statistics */
+    VIR_DOMAIN_MEMORY_STAT_LAST_UPDATE     = 8,
+
     /*
      * The number of statistics supported by this version of the interface.
      * To add new statistics, add them to the enum and increase this value.
      */
-    VIR_DOMAIN_MEMORY_STAT_NR              = 8,
+    VIR_DOMAIN_MEMORY_STAT_NR              = 9,
 
 # ifdef VIR_ENUM_SENTINELS
     VIR_DOMAIN_MEMORY_STAT_LAST = VIR_DOMAIN_MEMORY_STAT_NR
diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
index 3e144b6..b1c7d73 100644
--- a/src/libvirt-domain.c
+++ b/src/libvirt-domain.c
@@ -5988,6 +5988,8 @@ virDomainGetInterfaceParameters(virDomainPtr domain,
  *     The total amount of memory available to the domain's OS (in kb).
  * VIR_DOMAIN_MEMORY_STAT_ACTUAL_BALLOON:
  *     Current balloon value (in kb).
+ * VIR_DOMAIN_MEMORY_STAT_LAST_UPDATE
+ *     Timestamp of the last statistic
  *
  * Returns: The number of stats provided or -1 in case of failure.
  */
diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
index e767414..175ef10 100644
--- a/src/qemu/qemu_monitor_json.c
+++ b/src/qemu/qemu_monitor_json.c
@@ -1602,10 +1602,10 @@ qemuMonitorJSONGetBalloonInfo(qemuMonitorPtr mon,
  * rates and/or whether data has been collected since a previous cycle.
  * It's currently unused.
  */
-#define GET_BALLOON_STATS(FIELD, TAG, DIVISOR)                                \
-    if (virJSONValueObjectHasKey(statsdata, FIELD) &&                         \
+#define GET_BALLOON_STATS(OBJECT, FIELD, TAG, DIVISOR)                        \
+    if (virJSONValueObjectHasKey(OBJECT, FIELD) &&                            \
        (got < nr_stats)) {                                                    \
-        if (virJSONValueObjectGetNumberUlong(statsdata, FIELD, &mem) < 0) {   \
+        if (virJSONValueObjectGetNumberUlong(OBJECT, FIELD, &mem) < 0) {      \
             VIR_DEBUG("Failed to get '%s' value", FIELD);                     \
         } else {                                                              \
             /* Not being collected? No point in providing bad data */         \
@@ -1676,19 +1676,20 @@ int qemuMonitorJSONGetMemoryStats(qemuMonitorPtr mon,
         goto cleanup;
     }
 
-    GET_BALLOON_STATS("stat-swap-in",
+    GET_BALLOON_STATS(statsdata, "stat-swap-in",
                       VIR_DOMAIN_MEMORY_STAT_SWAP_IN, 1024);
-    GET_BALLOON_STATS("stat-swap-out",
+    GET_BALLOON_STATS(statsdata, "stat-swap-out",
                       VIR_DOMAIN_MEMORY_STAT_SWAP_OUT, 1024);
-    GET_BALLOON_STATS("stat-major-faults",
+    GET_BALLOON_STATS(statsdata, "stat-major-faults",
                       VIR_DOMAIN_MEMORY_STAT_MAJOR_FAULT, 1);
-    GET_BALLOON_STATS("stat-minor-faults",
+    GET_BALLOON_STATS(statsdata, "stat-minor-faults",
                       VIR_DOMAIN_MEMORY_STAT_MINOR_FAULT, 1);
-    GET_BALLOON_STATS("stat-free-memory",
+    GET_BALLOON_STATS(statsdata, "stat-free-memory",
                       VIR_DOMAIN_MEMORY_STAT_UNUSED, 1024);
-    GET_BALLOON_STATS("stat-total-memory",
+    GET_BALLOON_STATS(statsdata, "stat-total-memory",
                       VIR_DOMAIN_MEMORY_STAT_AVAILABLE, 1024);
-
+    GET_BALLOON_STATS(data, "last-update",
+                      VIR_DOMAIN_MEMORY_STAT_LAST_UPDATE, 1);
 
  cleanup:
     virJSONValueFree(cmd);
diff --git a/tools/virsh-domain-monitor.c b/tools/virsh-domain-monitor.c
index 0a93949..3893b90 100644
--- a/tools/virsh-domain-monitor.c
+++ b/tools/virsh-domain-monitor.c
@@ -373,6 +373,8 @@ cmdDomMemStat(vshControl *ctl, const vshCmd *cmd)
             vshPrint(ctl, "actual %llu\n", stats[i].val);
         if (stats[i].tag == VIR_DOMAIN_MEMORY_STAT_RSS)
             vshPrint(ctl, "rss %llu\n", stats[i].val);
+        if (stats[i].tag == VIR_DOMAIN_MEMORY_STAT_LAST_UPDATE)
+            vshPrint(ctl, "last_update %llu\n", stats[i].val);
     }
 
     ret = true;
-- 
1.9.5.msysgit.0