[PATCH 4/6] Implement domainGetCPUStats for lxc driver.

[Thorsten Behrens <tbehrens@xxxxxxxx>]

---
 src/lxc/lxc_driver.c | 132 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 132 insertions(+)

diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c
index 9f586af..1e9c77a 100644
--- a/src/lxc/lxc_driver.c
+++ b/src/lxc/lxc_driver.c
@@ -75,6 +75,8 @@
 
 
 #define LXC_NB_MEM_PARAM  3
+#define LXC_NB_PER_CPU_STAT_PARAM 1
+
 
 static int lxcStateInitialize(bool privileged,
                               virStateInhibitCallback callback,
@@ -4775,6 +4777,135 @@ cleanup:
 }
 
 
+static int
+lxcDomainGetPercpuStats(virDomainObjPtr vm,
+                        virTypedParameterPtr params,
+                        unsigned int nparams,
+                        int start_cpu,
+                        unsigned int ncpus)
+{
+    int rv = -1;
+    size_t i;
+    int id, max_id;
+    char *pos;
+    char *buf = NULL;
+    unsigned int n = 0;
+    virLXCDomainObjPrivatePtr priv = vm->privateData;
+    virTypedParameterPtr ent;
+    int param_idx;
+    unsigned long long cpu_time;
+
+    /* TODO: share api contract code with other drivers here */
+
+    /* return the number of supported params */
+    if (nparams == 0 && ncpus != 0)
+        return LXC_NB_PER_CPU_STAT_PARAM;
+
+    /* To parse account file, we need to know how many cpus are present.  */
+    max_id = nodeGetCPUCount();
+    if (max_id < 0)
+        return rv;
+
+    if (ncpus == 0) { /* returns max cpu ID */
+        rv = max_id;
+        goto cleanup;
+    }
+
+    if (start_cpu > max_id) {
+        virReportError(VIR_ERR_INVALID_ARG,
+                       _("start_cpu %d larger than maximum of %d"),
+                       start_cpu, max_id);
+        goto cleanup;
+    }
+
+    /* we get percpu cputime accounting info. */
+    if (virCgroupGetCpuacctPercpuUsage(priv->cgroup, &buf))
+        goto cleanup;
+    pos = buf;
+    memset(params, 0, nparams * ncpus);
+
+    /* return percpu cputime in index 0 */
+    param_idx = 0;
+
+    /* number of cpus to compute */
+    if (start_cpu >= max_id - ncpus)
+        id = max_id - 1;
+    else
+        id = start_cpu + ncpus - 1;
+
+    for (i = 0; i <= id; i++) {
+        if (virStrToLong_ull(pos, &pos, 10, &cpu_time) < 0) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("cpuacct parse error"));
+            goto cleanup;
+        } else {
+            n++;
+        }
+        if (i < start_cpu)
+            continue;
+        ent = &params[(i - start_cpu) * nparams + param_idx];
+        if (virTypedParameterAssign(ent, VIR_DOMAIN_CPU_STATS_CPUTIME,
+                                    VIR_TYPED_PARAM_ULLONG, cpu_time) < 0)
+            goto cleanup;
+    }
+
+    rv = nparams;
+
+cleanup:
+    VIR_FREE(buf);
+    return rv;
+}
+
+
+static int
+lxcDomainGetCPUStats(virDomainPtr dom,
+                     virTypedParameterPtr params,
+                     unsigned int nparams,
+                     int start_cpu,
+                     unsigned int ncpus,
+                     unsigned int flags)
+{
+    virDomainObjPtr vm = NULL;
+    int ret = -1;
+    bool isActive;
+    virLXCDomainObjPrivatePtr priv;
+
+    virCheckFlags(VIR_TYPED_PARAM_STRING_OKAY, -1);
+
+    if (!(vm = lxcDomObjFromDomain(dom)))
+        return ret;
+
+    priv = vm->privateData;
+
+    if (virDomainGetCPUStatsEnsureACL(dom->conn, vm->def) < 0)
+        goto cleanup;
+
+    isActive = virDomainObjIsActive(vm);
+    if (!isActive) {
+        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                       _("domain is not running"));
+        goto cleanup;
+    }
+
+    if (!virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_CPUACCT)) {
+        virReportError(VIR_ERR_OPERATION_INVALID,
+                       "%s", _("cgroup CPUACCT controller is not mounted"));
+        goto cleanup;
+    }
+
+    if (start_cpu == -1)
+        ret = virCgroupGetDomainTotalCPUStats(priv->cgroup,
+                                              params, nparams);
+    else
+        ret = lxcDomainGetPercpuStats(vm, params, nparams,
+                                      start_cpu, ncpus);
+cleanup:
+    if (vm)
+        virObjectUnlock(vm);
+    return ret;
+}
+
+
 /* Function Tables */
 static virDriver lxcDriver = {
     .no = VIR_DRV_LXC,
@@ -4852,6 +4983,7 @@ static virDriver lxcDriver = {
     .nodeSuspendForDuration = lxcNodeSuspendForDuration, /* 0.9.8 */
     .domainSetMetadata = lxcDomainSetMetadata, /* 1.1.3 */
     .domainGetMetadata = lxcDomainGetMetadata, /* 1.1.3 */
+    .domainGetCPUStats = lxcDomainGetCPUStats, /* 0.9.11 */
     .nodeGetMemoryParameters = lxcNodeGetMemoryParameters, /* 0.10.2 */
     .nodeSetMemoryParameters = lxcNodeSetMemoryParameters, /* 0.10.2 */
     .domainSendProcessSignal = lxcDomainSendProcessSignal, /* 1.0.1 */
-- 
1.8.4

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