On Thu, Aug 21, 2014 at 03:42:53PM +0800, Zhangjie (HZ) wrote: > 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.
Could you please try to apply the patch [PATCH V4] net: Forbid dealing with packets when VM is not running on top and see if this helps? Thanks! > -- > Best Wishes! > Zhang Jie