[libvirt] [PATCH 1/8] qemu: bulk stats: extend internal collection API

[Francesco Romani]

Future patches which will implement more
bulk stats groups for QEMU will need to access
the connection object.

To accomodate that, a few changes are needed:

* enrich internal prototype to pass connection object.
* add per-group flag to mark if one collector needs
  monitor access or not.
* if at least one collector of the requested stats
  needs monitor access, thus we must start a query job
  for each domain. The specific collectors will
  run nested monitor jobs inside that.

Signed-off-by: Francesco Romani <fromani at redhat.com>
---
 src/qemu/qemu_driver.c | 51 ++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 43 insertions(+), 8 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index d724eeb..2950a4b 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -17314,7 +17314,8 @@ qemuConnectGetDomainCapabilities(virConnectPtr conn,
 
 
 static int
-qemuDomainGetStatsState(virDomainObjPtr dom,
+qemuDomainGetStatsState(virConnectPtr conn ATTRIBUTE_UNUSED,
+                        virDomainObjPtr dom,
                         virDomainStatsRecordPtr record,
                         int *maxparams,
                         unsigned int privflags ATTRIBUTE_UNUSED)
@@ -17338,7 +17339,8 @@ qemuDomainGetStatsState(virDomainObjPtr dom,
 
 
 typedef int
-(*qemuDomainGetStatsFunc)(virDomainObjPtr dom,
+(*qemuDomainGetStatsFunc)(virConnectPtr conn,
+                          virDomainObjPtr dom,
                           virDomainStatsRecordPtr record,
                           int *maxparams,
                           unsigned int flags);
@@ -17346,11 +17348,12 @@ typedef int
 struct qemuDomainGetStatsWorker {
     qemuDomainGetStatsFunc func;
     unsigned int stats;
+    bool monitor;
 };
 
 static struct qemuDomainGetStatsWorker qemuDomainGetStatsWorkers[] = {
-    { qemuDomainGetStatsState, VIR_DOMAIN_STATS_STATE},
-    { NULL, 0 }
+    { qemuDomainGetStatsState, VIR_DOMAIN_STATS_STATE, false },
+    { NULL, 0, false }
 };
 
 
@@ -17382,6 +17385,20 @@ qemuDomainGetStatsCheckSupport(unsigned int *stats,
 }
 
 
+static bool
+qemuDomainGetStatsNeedMonitor(unsigned int stats)
+{
+    size_t i;
+
+    for (i = 0; qemuDomainGetStatsWorkers[i].func; i++)
+        if (stats & qemuDomainGetStatsWorkers[i].stats)
+            if (qemuDomainGetStatsWorkers[i].monitor)
+                return true;
+
+    return false;
+}
+
+
 static int
 qemuDomainGetStats(virConnectPtr conn,
                    virDomainObjPtr dom,
@@ -17399,7 +17416,7 @@ qemuDomainGetStats(virConnectPtr conn,
 
     for (i = 0; qemuDomainGetStatsWorkers[i].func; i++) {
         if (stats & qemuDomainGetStatsWorkers[i].stats) {
-            if (qemuDomainGetStatsWorkers[i].func(dom, tmp, &maxparams,
+            if (qemuDomainGetStatsWorkers[i].func(conn, dom, tmp, &maxparams,
                                                   flags) < 0)
                 goto cleanup;
         }
@@ -17435,6 +17452,7 @@ qemuConnectGetAllDomainStats(virConnectPtr conn,
     virDomainObjPtr dom = NULL;
     virDomainStatsRecordPtr *tmpstats = NULL;
     bool enforce = !!(flags & VIR_CONNECT_GET_ALL_DOMAINS_STATS_ENFORCE_STATS);
+    bool needmon = false;
     int ntempdoms;
     int nstats = 0;
     size_t i;
@@ -17473,6 +17491,8 @@ qemuConnectGetAllDomainStats(virConnectPtr conn,
     if (VIR_ALLOC_N(tmpstats, ndoms + 1) < 0)
         goto cleanup;
 
+    needmon = qemuDomainGetStatsNeedMonitor(stats);
+
     for (i = 0; i < ndoms; i++) {
         virDomainStatsRecordPtr tmp = NULL;
 
@@ -17483,11 +17503,21 @@ qemuConnectGetAllDomainStats(virConnectPtr conn,
             !virConnectGetAllDomainStatsCheckACL(conn, dom->def))
             continue;
 
-        if (qemuDomainGetStats(conn, dom, stats, &tmp, flags) < 0)
+        if (needmon && qemuDomainObjBeginJob(driver, dom, QEMU_JOB_QUERY) < 0)
             goto cleanup;
 
-        if (tmp)
-            tmpstats[nstats++] = tmp;
+        if ((needmon && virDomainObjIsActive(dom)) || !needmon) {
+            if (qemuDomainGetStats(conn, dom, stats, &tmp, flags) < 0)
+                goto endjob;
+
+            if (tmp)
+                tmpstats[nstats++] = tmp;
+        }
+
+        if (needmon && !qemuDomainObjEndJob(driver, dom)) {
+            dom = NULL;
+            goto cleanup;
+        }
 
         virObjectUnlock(dom);
         dom = NULL;
@@ -17498,6 +17528,11 @@ qemuConnectGetAllDomainStats(virConnectPtr conn,
 
     ret = nstats;
 
+ endjob:
+    if (needmon && dom)
+        if (!qemuDomainObjEndJob(driver, dom))
+            dom = NULL;
+
  cleanup:
     if (dom)
         virObjectUnlock(dom);
-- 
1.9.3