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: Han Han <hhan@redhat.com>
---
 include/libvirt/libvirt-domain.h | 14 +++++++++++++-
 src/libvirt-domain.c             |  5 ++++-
 src/qemu/qemu_driver.c           |  2 ++
 src/qemu/qemu_monitor_json.c     |  5 +++++
 tools/virsh-domain-monitor.c     |  4 ++++
 tools/virsh.pod                  |  2 ++
 6 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
index 7d36820b5a..192d25c1db 100644
--- a/include/libvirt/libvirt-domain.h
+++ b/include/libvirt/libvirt-domain.h
@@ -636,11 +636,23 @@ typedef enum {
      */
     VIR_DOMAIN_MEMORY_STAT_DISK_CACHES     = 10,

+    /*
+     * The amount of successful hugetlb(Huge Page Tables) allocations via
+     * virtio balloon.
+     */
+    VIR_DOMAIN_MEMORY_STAT_HUGETLB_PGALLOC    = 11,
+
+    /*
+     * The amount of failed hugetlb(Huge Page Tables) allocations 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
diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
index 80284a99f0..a95690e8a4 100644
--- a/src/libvirt-domain.c
+++ b/src/libvirt-domain.c
@@ -5734,7 +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 hugetlb(Huge Page Tables) allocations
+ * VIR_DOMAIN_MEMORY_STAT_HUGETLB_PGFAIL
+ *     The amount of failed hugetlb(Huge Page Tables) allocations
  * Returns: The number of stats provided or -1 in case of failure.
  */
 int
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index f48d9256e4..2d849beac8 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -20245,6 +20245,8 @@ 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
diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
index 908967f46c..5e3df5e759 100644
--- a/src/qemu/qemu_monitor_json.c
+++ b/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);
diff --git a/tools/virsh-domain-monitor.c b/tools/virsh-domain-monitor.c
index d87475f6f6..0092a9786e 100644
--- a/tools/virsh-domain-monitor.c
+++ b/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;
diff --git a/tools/virsh.pod b/tools/virsh.pod
index afc1684db0..ef27c527d6 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -938,6 +938,8 @@ 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 table allocations
+  hugetlb_pgfail    - The number of failed huge page table allocations

 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
--
2.20.1