On Fri, Jun 02, 2017 at 02:56:04AM +0300, Michael S. Tsirkin wrote: > commit d85b758f72b0 "virtio_net: fix support for small rings" > was supposed to increase the buffer size for small rings > but had an unintentional side effect of decreasing > it for large rings. This seems to break some setups - > it's not yet clear why, but increasing buffer size > back to what it was before helps. > > Fixes: d85b758f72b0 "virtio_net: fix support for small rings" > Reported-by: Mikulas Patocka <mpato...@redhat.com> > Reported-by: "J. Bruce Fields" <bfie...@fieldses.org> > Signed-off-by: Michael S. Tsirkin <m...@redhat.com> > --- > > Can reporters please confirm whether the following helps?
Works for me. --b. > If it does I think we should queue it even though I expect I'll need to > investigate the exact reasons for the failure down the road - probably > a hypervisor bug. > > drivers/net/virtio_net.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 87b5c20..60abb5d 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -842,7 +842,7 @@ static unsigned int get_mergeable_buf_len(struct > receive_queue *rq, > unsigned int len; > > len = hdr_len + clamp_t(unsigned int, ewma_pkt_len_read(avg_pkt_len), > - rq->min_buf_len - hdr_len, PAGE_SIZE - hdr_len); > + rq->min_buf_len, PAGE_SIZE - hdr_len); > return ALIGN(len, L1_CACHE_BYTES); > } > > @@ -2039,7 +2039,8 @@ static unsigned int mergeable_min_buf_len(struct > virtnet_info *vi, struct virtqu > unsigned int buf_len = hdr_len + ETH_HLEN + VLAN_HLEN + packet_len; > unsigned int min_buf_len = DIV_ROUND_UP(buf_len, rq_size); > > - return max(min_buf_len, hdr_len); > + return max(max(min_buf_len, hdr_len) - hdr_len, > + (unsigned int)GOOD_PACKET_LEN); > } > > static int virtnet_find_vqs(struct virtnet_info *vi) > -- > MST
