From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: vhost-net patches Date: Tue, 27 Oct 2009 17:27:54 +0200 Message-ID: <20091027152753.GA4622@redhat.com> References: <20091022174344.GA10821@redhat.com> <1256234420.27706.5.camel@w-sridhar.beaverton.ibm.com> <20091023110438.GA20229@redhat.com> <1256310168.4443.2.camel@localhost.localdomain> <1256310765.4443.4.camel@localhost.localdomain> <1256315020.4443.12.camel@localhost.localdomain> <20091026200513.GA26623@redhat.com> <1256592889.10142.8.camel@localhost.localdomain> <20091027064302.GB26914@redhat.com> <1256654819.4753.6.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Sridhar Samudrala , Shirley Ma , David Stevens , kvm@vger.kernel.org, sri@linux.vnet.ibm.com, mashirle@linux.vnet.ibm.com To: Shirley Ma Return-path: Received: from mx1.redhat.com ([209.132.183.28]:46787 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755497AbZJ0PaZ (ORCPT ); Tue, 27 Oct 2009 11:30:25 -0400 Content-Disposition: inline In-Reply-To: <1256654819.4753.6.camel@localhost.localdomain> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Oct 27, 2009 at 07:46:59AM -0700, Shirley Ma wrote: > 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? Possibly GFP_ATOMIC allocations in vring_add_indirect are failing? Is there a chance you are tight on guest memory for some reason? with vhost, virtio does currently consume a bit more memory than with userspace backend. > 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