Revert "qemu: do not put a task into machine cgroup"

This reverts commit a41c00b4.

After much testing and upstream discussion this has been deemed to be
the incorrect operation since it means we no longer have any guarantee
about which resource controllers the QEMU processes in general are in.

src/qemu/qemu_cgroup.c

@@ -789,6 +789,17 @@ qemuInitCgroup(virQEMUDriverPtr driver,
         goto cleanup;
     }
 
+    if (virCgroupAddTask(priv->cgroup, vm->pid) < 0) {
+        virErrorPtr saved = virSaveLastError();
+        virCgroupRemove(priv->cgroup);
+        virCgroupFree(&priv->cgroup);
+        if (saved) {
+            virSetError(saved);
+            virFreeError(saved);
+        }
+        goto cleanup;
+    }
+
  done:
     ret = 0;
  cleanup:
@@ -1160,10 +1171,6 @@ qemuSetupCgroupForEmulator(virDomainObjPtr vm)
             goto cleanup;
     }
 
-    /* consider the first thread an emulator-thread */
-    if (virCgroupAddTask(cgroup_emulator, vm->pid) < 0)
-        goto cleanup;
-
     virCgroupFree(&cgroup_emulator);
     return 0;
 

src/qemu/qemu_process.c

@@ -4895,6 +4895,12 @@ qemuProcessLaunch(virConnectPtr conn,
     if (qemuSetupCgroup(driver, vm, nnicindexes, nicindexes) < 0)
         goto cleanup;
 
+    /* This must be done after cgroup placement to avoid resetting CPU
+     * affinity */
+    if (!vm->def->cputune.emulatorpin &&
+        qemuProcessInitCpuAffinity(vm) < 0)
+        goto cleanup;
+
     VIR_DEBUG("Setting domain security labels");
     if (virSecurityManagerSetAllLabel(driver->securityManager,
                                       vm->def,
@@ -4941,12 +4947,6 @@ qemuProcessLaunch(virConnectPtr conn,
     if (qemuSetupCgroupForEmulator(vm) < 0)
         goto cleanup;
 
-    /* This must be done after cgroup placement to avoid resetting CPU
-     * affinity */
-    if (!vm->def->cputune.emulatorpin &&
-        qemuProcessInitCpuAffinity(vm) < 0)
-        goto cleanup;
-
     VIR_DEBUG("Setting affinity of emulator threads");
     if (qemuProcessSetEmulatorAffinity(vm) < 0)
         goto cleanup;