[virt-tools-list] [PATCHv2 2/2] Base mem statistics on virDomainMemoryStats if available.

[Thorsten Behrens]

Attempt to query domain memory stats via virDomainMemoryStats.
Fallback to old, possibly static virDomainGetInfo when that fails.
---
 virtManager/domain.py | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/virtManager/domain.py b/virtManager/domain.py
index c94ac57..11488f9 100644
--- a/virtManager/domain.py
+++ b/virtManager/domain.py
@@ -245,6 +245,8 @@ class vmmDomain(vmmLibvirtObject):
         self.remote_console_supported = False
         self.title_supported = False
 
+        self._mem_stats_supported = True
+
         self._enable_net_poll = False
         self._stats_net_supported = True
         self._stats_net_skip = []
@@ -1360,11 +1362,30 @@ class vmmDomain(vmmLibvirtObject):
     ###################
 
     def _sample_mem_stats(self, info):
+        # fallback - if the below fails, have at least the old
+        # virDomainGetInfo data at hand
         curmem = info[2]
-        if not self.is_active():
+        totalmem = self.maximum_memory()
+        if (not self._mem_stats_supported or
+            not self.is_active()):
             curmem = 0
+        else:
+            # retrieve dynamic mem stats, if supported
+            try:
+                stats = self._backend.memoryStats()
+                # did we get both required stat items back?
+                if set(['actual', 'rss']).issubset(
+                        set(stats.keys())):
+                    curmem = stats['rss']
+                    totalmem = stats['actual']
+            except libvirt.libvirtError, err:
+                if util.is_error_nosupport(err):
+                    logging.debug("Mem stats not supported: %s", err)
+                    self._mem_stats_supported = False
+                else:
+                    logging.error("Error reading mem stats: %s", err)
 
-        pcentCurrMem = curmem * 100.0 / self.maximum_memory()
+        pcentCurrMem = curmem * 100.0 / totalmem
         pcentCurrMem = max(0.0, min(pcentCurrMem, 100.0))
 
         return pcentCurrMem, curmem
-- 
1.8.4