qemu: Add entry for balloon stats stat-htlb-pgalloc and stat-htlb-pgfail

Qemu added reporting of virtio balloon new statistics stat-htlb-pgalloc and
stat-htlb-pgfail since qemu-3.0 commit b7b12644297. The value of
stat-htlb-pgalloc represents the number of successful hugetlb page allocations
while stat-htlb-pgfail represents the number of failed ones. Add this
statistics reporting to libvirt.

To enable this feature for vm, guest kenel >= 4.17 is required because
the exporting hugetlb page allocation for virtio balloon is introduced
since 6c64fe7f.
Signed-off-by: NHan Han <hhan@redhat.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

include/libvirt/libvirt-domain.h

@@ -636,11 +636,23 @@ typedef enum {
      */
     VIR_DOMAIN_MEMORY_STAT_DISK_CACHES     = 10,
 
+    /*
+     * The amount of successful huge page allocations from inside the domain via
+     * virtio balloon.
+     */
+    VIR_DOMAIN_MEMORY_STAT_HUGETLB_PGALLOC    = 11,
+
+    /*
+     * The amount of failed huge page allocations from inside the domain via
+     * virtio balloon.
+     */
+    VIR_DOMAIN_MEMORY_STAT_HUGETLB_PGFAIL    = 12,
+
     /*
      * 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              = 11,
+    VIR_DOMAIN_MEMORY_STAT_NR              = 13,
 
 # ifdef VIR_ENUM_SENTINELS
     VIR_DOMAIN_MEMORY_STAT_LAST = VIR_DOMAIN_MEMORY_STAT_NR

src/libvirt-domain.c

@@ -5734,6 +5734,10 @@ virDomainGetInterfaceParameters(virDomainPtr domain,
  * VIR_DOMAIN_MEMORY_STAT_DISK_CACHES
  *     Memory that can be reclaimed without additional I/O, typically disk
  *     caches (in kb).
+ * VIR_DOMAIN_MEMORY_STAT_HUGETLB_PGALLOC
+ *     The amount of successful huge page allocations from inside the domain
+ * VIR_DOMAIN_MEMORY_STAT_HUGETLB_PGFAIL
+ *     The amount of failed huge page allocations from inside the domain
  *
  * Returns: The number of stats provided or -1 in case of failure.
  */

src/qemu/qemu_driver.c

@@ -20248,6 +20248,8 @@ qemuDomainGetStatsBalloon(virQEMUDriverPtr driver,
         STORE_MEM_RECORD(LAST_UPDATE, "last-update")
         STORE_MEM_RECORD(USABLE, "usable")
         STORE_MEM_RECORD(DISK_CACHES, "disk_caches")
+        STORE_MEM_RECORD(HUGETLB_PGALLOC, "hugetlb_pgalloc")
+        STORE_MEM_RECORD(HUGETLB_PGFAIL, "hugetlb_pgfail")
     }
 
 #undef STORE_MEM_RECORD

src/qemu/qemu_monitor_json.c

@@ -2150,6 +2150,11 @@ int qemuMonitorJSONGetMemoryStats(qemuMonitorPtr mon,
                       VIR_DOMAIN_MEMORY_STAT_LAST_UPDATE, 1);
     GET_BALLOON_STATS(statsdata, "stat-disk-caches",
                       VIR_DOMAIN_MEMORY_STAT_DISK_CACHES, 1024);
+    GET_BALLOON_STATS(statsdata, "stat-htlb-pgalloc",
+                      VIR_DOMAIN_MEMORY_STAT_HUGETLB_PGALLOC, 1);
+    GET_BALLOON_STATS(statsdata, "stat-htlb-pgfail",
+                      VIR_DOMAIN_MEMORY_STAT_HUGETLB_PGFAIL, 1);
+
     ret = got;
  cleanup:
     virJSONValueFree(cmd);

tools/virsh-domain-monitor.c

@@ -376,6 +376,10 @@ cmdDomMemStat(vshControl *ctl, const vshCmd *cmd)
             vshPrint(ctl, "last_update %llu\n", stats[i].val);
         if (stats[i].tag == VIR_DOMAIN_MEMORY_STAT_DISK_CACHES)
             vshPrint(ctl, "disk_caches %llu\n", stats[i].val);
+        if (stats[i].tag == VIR_DOMAIN_MEMORY_STAT_HUGETLB_PGALLOC)
+            vshPrint(ctl, "hugetlb_pgalloc %llu\n", stats[i].val);
+        if (stats[i].tag == VIR_DOMAIN_MEMORY_STAT_HUGETLB_PGFAIL)
+            vshPrint(ctl, "hugetlb_pgfail %llu\n", stats[i].val);
     }
 
     ret = true;

tools/virsh.pod

@@ -938,6 +938,10 @@ without causing host swapping (in KiB)
   last-update       - Timestamp of the last update of statistics (in seconds)
   disk_caches       - The amount of memory that can be reclaimed without
 additional I/O, typically disk caches (in KiB)
+  hugetlb_pgalloc   - The number of successful huge page allocations initiated
+from within the domain
+  hugetlb_pgfail    - The number of failed huge page allocations initiated from
+within the domain
 
 For QEMU/KVM with a memory balloon, setting the optional I<--period> to a
 value larger than 0 in seconds will allow the balloon driver to return