libxl: implement virDomainGetJobInfo

Introduce support for domainGetJobInfo to get info about the
ongoing job. If the job is active it will update the
timeElapsed which is computed with the "started" field added to
struct libxlDomainJobObj.  For now we support just the very basic
info and all jobs have VIR_DOMAIN_JOB_UNBOUNDED (i.e. no completion
time estimation) plus timeElapsed computed.

Openstack Kilo uses the Job API to monitor live-migration
progress which is currently nonexistent in libxl driver and
therefore leads to a crash in the nova compute node. Right
now, migration doesn't use jobs in the source node and will
return VIR_DOMAIN_JOB_NONE. Though nova handles this case and
will migrate it properly instead of crashing.
Signed-off-by: NJoao Martins <joao.m.martins@oracle.com>

src/libxl/libxl_domain.c

@@ -74,6 +74,9 @@ libxlDomainObjInitJob(libxlDomainObjPrivatePtr priv)
     if (virCondInit(&priv->job.cond) < 0)
         return -1;
 
+    if (VIR_ALLOC(priv->job.current) < 0)
+        return -1;
+
     return 0;
 }
 
@@ -90,6 +93,7 @@ static void
 libxlDomainObjFreeJob(libxlDomainObjPrivatePtr priv)
 {
     ignore_value(virCondDestroy(&priv->job.cond));
+    VIR_FREE(priv->job.current);
 }
 
 /* Give up waiting for mutex after 30 seconds */
@@ -131,6 +135,8 @@ libxlDomainObjBeginJob(libxlDriverPrivatePtr driver ATTRIBUTE_UNUSED,
     VIR_DEBUG("Starting job: %s", libxlDomainJobTypeToString(job));
     priv->job.active = job;
     priv->job.owner = virThreadSelfID();
+    priv->job.started = now;
+    priv->job.current->type = VIR_DOMAIN_JOB_UNBOUNDED;
 
     return 0;
 
@@ -179,6 +185,27 @@ libxlDomainObjEndJob(libxlDriverPrivatePtr driver ATTRIBUTE_UNUSED,
     return virObjectUnref(obj);
 }
 
+int
+libxlDomainJobUpdateTime(struct libxlDomainJobObj *job)
+{
+    virDomainJobInfoPtr jobInfo = job->current;
+    unsigned long long now;
+
+    if (!job->started)
+        return 0;
+
+    if (virTimeMillisNow(&now) < 0)
+        return -1;
+
+    if (now < job->started) {
+        job->started = 0;
+        return 0;
+    }
+
+    jobInfo->timeElapsed = now - job->started;
+    return 0;
+}
+
 static void *
 libxlDomainObjPrivateAlloc(void)
 {

src/libxl/libxl_domain.h

@@ -53,6 +53,8 @@ struct libxlDomainJobObj {
     virCond cond;                       /* Use to coordinate jobs */
     enum libxlDomainJob active;         /* Currently running job */
     int owner;                          /* Thread which set current job */
+    unsigned long long started;         /* When the job started */
+    virDomainJobInfoPtr current;        /* Statistics for the current job */
 };
 
 typedef struct _libxlDomainObjPrivate libxlDomainObjPrivate;
@@ -88,6 +90,10 @@ libxlDomainObjEndJob(libxlDriverPrivatePtr driver,
                      virDomainObjPtr obj)
     ATTRIBUTE_RETURN_CHECK;
 
+int
+libxlDomainJobUpdateTime(struct libxlDomainJobObj *job)
+    ATTRIBUTE_RETURN_CHECK;
+
 void
 libxlDomainEventQueue(libxlDriverPrivatePtr driver,
                       virObjectEventPtr event);

src/libxl/libxl_driver.c

@@ -4840,6 +4840,44 @@ libxlDomainMemoryStats(virDomainPtr dom,
 
 #undef LIBXL_SET_MEMSTAT
 
+static int
+libxlDomainGetJobInfo(virDomainPtr dom,
+                      virDomainJobInfoPtr info)
+{
+    libxlDomainObjPrivatePtr priv;
+    virDomainObjPtr vm;
+    int ret = -1;
+
+    if (!(vm = libxlDomObjFromDomain(dom)))
+        goto cleanup;
+
+    if (virDomainGetJobInfoEnsureACL(dom->conn, vm->def) < 0)
+        goto cleanup;
+
+    priv = vm->privateData;
+    if (!priv->job.active) {
+        memset(info, 0, sizeof(*info));
+        info->type = VIR_DOMAIN_JOB_NONE;
+        ret = 0;
+        goto cleanup;
+    }
+
+    /* In libxl we don't have an estimated completion time
+     * thus we always set to unbounded and update time
+     * for the active job. */
+    if (libxlDomainJobUpdateTime(&priv->job) < 0)
+        goto cleanup;
+
+    memcpy(info, priv->job.current, sizeof(virDomainJobInfo));
+    ret = 0;
+
+ cleanup:
+    if (vm)
+        virObjectUnlock(vm);
+    return ret;
+}
+
+
 static int
 libxlConnectDomainEventRegisterAny(virConnectPtr conn, virDomainPtr dom, int eventID,
                                    virConnectDomainEventGenericCallback callback,
@@ -5433,6 +5471,7 @@ static virHypervisorDriver libxlHypervisorDriver = {
 #endif
     .nodeGetFreeMemory = libxlNodeGetFreeMemory, /* 0.9.0 */
     .nodeGetCellsFreeMemory = libxlNodeGetCellsFreeMemory, /* 1.1.1 */
+    .domainGetJobInfo = libxlDomainGetJobInfo, /* 1.3.1 */
     .domainMemoryStats = libxlDomainMemoryStats, /* 1.3.0 */
     .domainGetCPUStats = libxlDomainGetCPUStats, /* 1.3.0 */
     .connectDomainEventRegister = libxlConnectDomainEventRegister, /* 0.9.0 */