qemu: fix live pinning to memory node on NUMA system

Ever since the subcpusets(vcpu,emulator) were introduced, the parent
cpuset cannot be modified to remove the nodes that are in use by the
subcpusets.
The fix is to break the memory node modification into three steps:
 1. assign new nodes into the parent,
 2. change the nodes in the child nodes,
 3. remove the old nodes on the parent node.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1009880Signed-off-by: NShivaprasad G Bhat <sbhat@linux.vnet.ibm.com>
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

src/qemu/qemu_driver.c

@@ -8133,6 +8133,84 @@ cleanup:
     return ret;
 }
 
+static int
+qemuDomainSetNumaParamsLive(virDomainObjPtr vm,
+                            virCapsPtr caps,
+                            virBitmapPtr nodeset)
+{
+    virCgroupPtr cgroup_temp = NULL;
+    virBitmapPtr temp_nodeset = NULL;
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+    char *nodeset_str = NULL;
+    size_t i = 0;
+    int ret = -1;
+
+    if (vm->def->numatune.memory.mode != VIR_DOMAIN_NUMATUNE_MEM_STRICT) {
+        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                       _("change of nodeset for running domain "
+                         "requires strict numa mode"));
+        goto cleanup;
+    }
+
+    /*Get Exisitng nodeset values */
+    if (virCgroupGetCpusetMems(priv->cgroup, &nodeset_str) < 0 ||
+        virBitmapParse(nodeset_str, 0, &temp_nodeset,
+                       VIR_DOMAIN_CPUMASK_LEN) < 0)
+        goto cleanup;
+    VIR_FREE(nodeset_str);
+
+    for (i = 0; i < caps->host.nnumaCell; i++) {
+        bool result;
+        if (virBitmapGetBit(nodeset, i, &result) < 0) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("Failed to get cpuset bit values"));
+            goto cleanup;
+        }
+        if (result && (virBitmapSetBit(temp_nodeset, i) < 0)) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("Failed to set temporary cpuset bit values"));
+            goto cleanup;
+        }
+    }
+
+    if (!(nodeset_str = virBitmapFormat(temp_nodeset))) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Failed to format nodeset"));
+        goto cleanup;
+    }
+
+    if (virCgroupSetCpusetMems(priv->cgroup, nodeset_str) < 0)
+        goto cleanup;
+    VIR_FREE(nodeset_str);
+
+    /* Ensure the cpuset string is formated before passing to cgroup */
+    if (!(nodeset_str = virBitmapFormat(nodeset))) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Failed to format nodeset"));
+        goto cleanup;
+    }
+
+    for (i = 0; i < priv->nvcpupids; i++) {
+        if (virCgroupNewVcpu(priv->cgroup, i, false, &cgroup_temp) < 0 ||
+            virCgroupSetCpusetMems(cgroup_temp, nodeset_str) < 0)
+            goto cleanup;
+        virCgroupFree(&cgroup_temp);
+    }
+
+    if (virCgroupNewEmulator(priv->cgroup, false, &cgroup_temp) < 0 ||
+        virCgroupSetCpusetMems(cgroup_temp, nodeset_str) < 0 ||
+        virCgroupSetCpusetMems(priv->cgroup, nodeset_str) < 0)
+        goto cleanup;
+
+    ret = 0;
+ cleanup:
+    VIR_FREE(nodeset_str);
+    virBitmapFree(temp_nodeset);
+    virCgroupFree(&cgroup_temp);
+
+    return ret;
+}
+
 static int
 qemuDomainSetNumaParameters(virDomainPtr dom,
                             virTypedParameterPtr params,
@@ -8200,7 +8278,6 @@ qemuDomainSetNumaParameters(virDomainPtr dom,
             }
         } else if (STREQ(param->field, VIR_DOMAIN_NUMA_NODESET)) {
             virBitmapPtr nodeset = NULL;
-            char *nodeset_str = NULL;
 
             if (virBitmapParse(params[i].value.s,
                                0, &nodeset,
@@ -8210,32 +8287,11 @@ qemuDomainSetNumaParameters(virDomainPtr dom,
             }
 
             if (flags & VIR_DOMAIN_AFFECT_LIVE) {
-                if (vm->def->numatune.memory.mode !=
-                    VIR_DOMAIN_NUMATUNE_MEM_STRICT) {
-                    virReportError(VIR_ERR_OPERATION_INVALID, "%s",
-                                   _("change of nodeset for running domain "
-                                     "requires strict numa mode"));
-                    virBitmapFree(nodeset);
-                    ret = -1;
-                    continue;
-                }
-
-                /* Ensure the cpuset string is formated before passing to cgroup */
-                if (!(nodeset_str = virBitmapFormat(nodeset))) {
-                    virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                                   _("Failed to format nodeset"));
-                    virBitmapFree(nodeset);
-                    ret = -1;
-                    continue;
-                }
-
-                if (virCgroupSetCpusetMems(priv->cgroup, nodeset_str) < 0) {
+                if (qemuDomainSetNumaParamsLive(vm, caps, nodeset) < 0) {
                     virBitmapFree(nodeset);
-                    VIR_FREE(nodeset_str);
                     ret = -1;
                     continue;
                 }
-                VIR_FREE(nodeset_str);
 
                 /* update vm->def here so that dumpxml can read the new
                  * values from vm->def. */