qemu: move setting emulatorpin ahead of monitor showing up

If VM is configured with many devices(including passthrough devices)
and large memory, libvirtd will take seconds(in the worst case) to
wait for monitor. In this period the qemu process may run on any
PCPU though I intend to pin emulator to the specified PCPU in xml
configuration.

Actually qemu process takes high cpu usage during vm startup.
So this is not the strict CPU isolation in this case.
Signed-off-by: NZhou yimin <zhouyimin@huawei.com>
(cherry picked from commit 411cea63)

src/qemu/qemu_process.c

@@ -4527,6 +4527,14 @@ int qemuProcessStart(virConnectPtr conn,
     if (ret == -1) /* The VM failed to start */
         goto cleanup;
 
+    VIR_DEBUG("Setting cgroup for emulator (if required)");
+    if (qemuSetupCgroupForEmulator(driver, vm, nodemask) < 0)
+        goto cleanup;
+
+    VIR_DEBUG("Setting affinity of emulator threads");
+    if (qemuProcessSetEmulatorAffinity(vm) < 0)
+        goto cleanup;
+
     VIR_DEBUG("Waiting for monitor to show up");
     if (qemuProcessWaitForMonitor(driver, vm, asyncJob, priv->qemuCaps, pos) < 0)
         goto cleanup;
@@ -4562,10 +4570,6 @@ int qemuProcessStart(virConnectPtr conn,
     if (qemuSetupCgroupForVcpu(vm) < 0)
         goto cleanup;
 
-    VIR_DEBUG("Setting cgroup for emulator (if required)");
-    if (qemuSetupCgroupForEmulator(driver, vm, nodemask) < 0)
-        goto cleanup;
-
     VIR_DEBUG("Setting cgroup for each IOThread (if required)");
     if (qemuSetupCgroupForIOThreads(vm) < 0)
         goto cleanup;
@@ -4574,10 +4578,6 @@ int qemuProcessStart(virConnectPtr conn,
     if (qemuProcessSetVcpuAffinities(vm) < 0)
         goto cleanup;
 
-    VIR_DEBUG("Setting affinity of emulator threads");
-    if (qemuProcessSetEmulatorAffinity(vm) < 0)
-        goto cleanup;
-
     VIR_DEBUG("Setting affinity of IOThread threads");
     if (qemuProcessSetIOThreadsAffinity(vm) < 0)
         goto cleanup;