On 2015/1/28 17:51, Xie, Huawei wrote: > > >> -----Original Message----- >> From: Linhaifeng [mailto:haifeng.lin at huawei.com] >> Sent: Tuesday, January 27, 2015 3:57 PM >> To: dpd >> dev at dpdk.org; ms >> Michael S. Tsirkin >> Cc: lilijun; liuyongan at huawei.com; Xie, Huawei >> Subject: vhost: virtio-net rx-ring stop work after work many hours,bug? >> >> Hi,all >> >> I use vhost-user to send data to VM at first it cant work well but after many >> hours VM can not receive data but can send data. >> >> (gdb)p avail_idx >> $4 = 2668 >> (gdb)p free_entries >> $5 = 0 >> (gdb)l >> /* check that we have enough buffers */ >> if (unlikely(count > free_entries)) >> count = free_entries; >> >> if (count == 0){ >> int b=0; >> if(b) { // when set b=1 to notify guest rx_ring will restart to >> work >> if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)) { >> >> eventfd_write(vq->callfd, 1); >> } >> } >> return 0; >> } >> >> some info i print in guest: >> >> net eth3:vi->num=199 >> net eth3:rvq info: num_free=57, used->idx=2668, avail->idx=2668 >> net eth3:svq info: num_free=254, used->idx=1644, avail->idx=1644 >> >> net eth3:vi->num=199 >> net eth3:rvq info: num_free=57, used->idx=2668, avail->idx=2668 >> net eth3:svq info: num_free=254, used->idx=1645, avail->idx=1645 >> >> net eth3:vi->num=199 >> net eth3:rvq info: num_free=57, used->idx=2668, avail->idx=2668 >> net eth3:svq info: num_free=254, used->idx=1646, avail->idx=1646 >> >> # free >> total used free shared buffers cached >> Mem: 3924100 337252 3586848 0 95984 138060 >> -/+ buffers/cache: 103208 3820892 >> Swap: 970748 0 970748 >> >> I have two questions: >> 1.Should we need to notify guest when there is no buffer in vq->avail? >> 2.Why virtio_net stop to fill avail? >> >> > > Haifeng: > Thanks for reporting this issue. > It might not be vhost-user specific, because as long vhost-user has received > all the vring information correctly, it shares the same code > receiving/transmitting packets with vhost-cuse. > Are you using latest patch or the old patch?
Xie: Sorry, I saw this mail until now. I use the old code not latest patch.The lastest patch is ok because it will notify guest after copy each pkt when merge-able.(May be is not OK when you close the merge-able feature) > 1 Do you disable merge-able feature support in vhost example? There is an > bug in vhost-user feature negotiation which is fixed in latest patch. It > could cause guest not receive packets at all. So if you are testing only > using linux net device, this isn't the cause. Yes, i disabled it. > 2.Do you still have the spot? Could you check if there are available > descriptors from checking the desc ring or even dump the vring status? Check > the notify_on_empty flag Michael mentioned? I find a bug in vhost library > when processing three or more chained descriptors. But if you never > re-configure eth0 with different features, this isn't the cause. > 3. Is this reproduce-able? Next time if you run long hours stability test, > could you try to disable guest virtio feature? > -device > virtio-net-pci,netdev=mynet0,mac=54:00:00:54:00:01,csum=off,gso=off,guest_tso4=off,guest_tso6=off,guest_ecn=off > > I have run more than ten hours' nightly test many times before, and haven't > met this issue. > We will check * if there is issue in the vhost code delivering interrupts to > guest which cause potential deadlock *if there are places we should but miss > delivering interrupts to guest. > >> >> >> >> >> -- >> Regards, >> Haifeng > -- Regards, Haifeng
