On Thu, Aug 14, 2014 at 04:52:40PM +0800, Jason Wang wrote:
> On 08/07/2014 08:47 PM, Zhangjie (HZ) wrote:
> > On 2014/8/5 20:14, Zhangjie (HZ) wrote:
> >> On 2014/8/5 17:49, Michael S. Tsirkin wrote:
> >>> On Tue, Aug 05, 2014 at 02:29:28PM +0800, Zhangjie (HZ) wrote:
> >>>> 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.
> >>> 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.
> >> @@ -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
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