virt plugin: do not report empty metrics

diff --git a/src/virt.c b/src/virt.c
index ff70864..2385f36 100644 (file)
--- a/src/virt.c
+++ b/src/virt.c
@@ -69,9 +69,9 @@
 #endif
 
 /*
-  virConnectListAllDomains() appeared in 0.10.2
-  Note that LIBVIR_CHECK_VERSION appeared a year later, so
-  in some systems which actually have virConnectListAllDomains()
+  virConnectListAllDomains() appeared in 0.10.2 (Sep 2012)
+  Note that LIBVIR_CHECK_VERSION appeared a year later (Dec 2013, libvirt-1.2.0),
+  so in some systems which actually have virConnectListAllDomains()
   we can't detect this.
  */
 #if LIBVIR_CHECK_VERSION(0, 10, 2)
@@ -1723,7 +1723,7 @@ static int get_memory_stats(virDomainPtr domain) {
     submit(domain, "swap_io", "out", &(value_t){.gauge = swap_out}, 1);
   }
 
-  if (min_flt > -1 || maj_flt > -1) {
+  if (min_flt > 0 || maj_flt > 0) {
     value_t values[] = {
         {.gauge = (gauge_t)min_flt}, {.gauge = (gauge_t)maj_flt},
     };