From mboxrd@z Thu Jan  1 00:00:00 1970
From: Shirley Ma <mashirle@us.ibm.com>
Subject: Re: vhost-net patches
Date: Tue, 27 Oct 2009 07:46:59 -0700
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Cc: Sridhar Samudrala <sri@us.ibm.com>, Shirley Ma <xma@us.ibm.com>,
	David Stevens <dlstevens@us.ibm.com>, kvm@vger.kernel.org,
	sri@linux.vnet.ibm.com, mashirle@linux.vnet.ibm.com
To: "Michael S. Tsirkin" <mst@redhat.com>
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Sender: kvm-owner@vger.kernel.org
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Hello Michael,

On Tue, 2009-10-27 at 08:43 +0200, Michael S. Tsirkin wrote:
> At some point my guest had a runaway nash-hotplug process
> consuming 100% CPU. Could you please verify this
> does not happen to you?

What I have found that the start_xmit stopped and restarted too often.
There is no vring descriptor available for adding the new buf. The buf
release is not able to keep up after vhost patch?

I saw lots of "Unexpected full queue" from dmesg. I haven't had time to
debug it yet. You might have some idea here?

        /* This can happen with OOM and indirect buffers. */
        if (unlikely(capacity < 0)) {
                netif_stop_queue(dev);
                dev_warn(&dev->dev, "Unexpected full queue\n");
                if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
                        vi->svq->vq_ops->disable_cb(vi->svq);
                        netif_start_queue(dev);
                        goto again;
                }
                return NETDEV_TX_BUSY;
        }

Thanks
Shirley