On Thu, Aug 14, 2014 at 04:52:40PM +0800, Jason Wang wrote:

On 08/07/2014 08:47 PM, Zhangjie (HZ) wrote:

quoted

On 2014/8/5 20:14, Zhangjie (HZ) wrote:

quoted

On 2014/8/5 17:49, Michael S. Tsirkin wrote:

quoted

On Tue, Aug 05, 2014 at 02:29:28PM +0800, Zhangjie (HZ) wrote:

quoted

Jason is right, the new order is not the cause of network unreachable.
Changing order seems not work. After about 40 times, the problem occurs again.
Maybe there is other hidden reasons for that.

I modified the code to change the order myself yesterday.
This result is about my code.

quoted

To make sure, you tested the patch that I posted to list:
"vhost_net: stop guest notifiers after backend"?

Please confirm.

OK, I will test with your patch "vhost_net: stop guest notifiers after backend".

Unfortunately, after using the patch "vhost_net: stop guest notifiers after backend",
Linux VMs stopt themselves a few minutes after they were started.

quoted

@@ -308,6 +308,12 @@ int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,
        goto err;
    }

+    r = k->set_guest_notifiers(qbus->parent, total_queues * 2, true);
+    if (r < 0) {
+        error_report("Error binding guest notifier: %d", -r);
+        goto err;
+    }
+
    for (i = 0; i < total_queues; i++) {
        r = vhost_net_start_one(get_vhost_net(ncs[i].peer), dev, i * 2);

@@ -316,12 +322,6 @@ int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,
        }
    }

-    r = k->set_guest_notifiers(qbus->parent, total_queues * 2, true);
-    if (r < 0) {
-        error_report("Error binding guest notifier: %d", -r);
-        goto err;
-    }
-
    return 0;

I wonder if k->set_guest_notifiers should be called after "hdev->started = true;" in vhost_dev_start.

Michael, can we just remove those assertions? Since you may want to set
guest notifiers before starting the backend.

Which assertions?

Another question for virtio_pci_vector_poll(): why not using
msix_notify() instead of msix_set_pending().

We can do that but the effect will be same since we know
vector is masked.

If so, there's no need to
change the vhost_net_start() ?

Confused, don't see the connection.

Zhang Jie, is this a regression? If yes, could you please do a bisection
to find the first bad commit.

Thanks

Pretty sure it's the mq patch: a9f98bb5ebe6fb1869321dcc58e72041ae626ad8

    Since we may have many vhost/net devices for a virtio-net device.  The setting of
    guest notifiers were moved out of the starting/stopping of a specific vhost
    thread. The vhost_net_{start|stop}() were renamed to
    vhost_net_{start|stop}_one(), and a new vhost_net_{start|stop}() were introduced
    to configure the guest notifiers and start/stop all vhost/vhost_net devices.

-- 
MST