From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43130) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XKN1h-0005t0-Ah for qemu-devel@nongnu.org; Thu, 21 Aug 2014 03:43:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XKN1b-0000B5-1H for qemu-devel@nongnu.org; Thu, 21 Aug 2014 03:43:17 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:40462) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XKN1a-0000Aj-93 for qemu-devel@nongnu.org; Thu, 21 Aug 2014 03:43:10 -0400 Message-ID: <53F5A2FD.2060405@huawei.com> Date: Thu, 21 Aug 2014 15:42:53 +0800 From: "Zhangjie (HZ)" MIME-Version: 1.0 References: <1408424189-10510-1-git-send-email-jasowang@redhat.com> <53F46909.2040101@huawei.com> <53F575AF.2010100@redhat.com> <53F59174.7010104@huawei.com> <53F59771.2050602@redhat.com> In-Reply-To: <53F59771.2050602@redhat.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH V3] vhost_net: start/stop guest notifiers properly List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jason Wang , qemu-devel@nongnu.org, mst@redhat.com Cc: William Dauchy On 2014/8/21 14:53, Jason Wang wrote: > On 08/21/2014 02:28 PM, Zhangjie (HZ) wrote: >> >> After migration, vhost is not disabled, virtual nic became unreachable because vhost is not awakened. >> By the logical of EVENT_IDX, virtio-net will not kick vhost again if the used idx is not updated. >> So, if one interrupts is lost during migration, virtio_net will not kick vhost again. >> Then, no skb from virtio-net can be sent to tap. > > Yes and I mean to test vhost=off to see if it was the issue of vhost. That sounds reasonable, but the test case is to test vhost. >> >> Jason's patch reduced the probability of occurrence, from about 1/20 to 1/80. It is really effective. I think the patch should be acked. >> May be we can try to solve the problem from another perspective. Do you have some methods to sense the migration? >> We can make up a signal from virtio-net after the migration. > > You can make a patch like this to debug. If problem disappears, it means > interrupt was really lost anyway. >> >>> Anyway, I will try to reproduce it by myself. >>> >> The test environment is really terrible, I build a environment myself, but it problem did not occur. >> The environment I use now is from a colleague Responsible for test work. >> Two hosts, every host has about 20 vms, they send packages(ipv4 and ipv6) between each other. >> The VM to be migrated also sens packages itself, and there is a ping(-i 0.001) from another host to it. >> The physical nic is 1GE, connected through a internal nework. > > Just want to confirm. For the problem did not occur, you mean with my > patch on top? > . > I mean, with your patch, I have to test 80 times before it occurs, the probability is reduced. -- Best Wishes! Zhang Jie