On 16-12-23 06:37 AM, Jason Wang wrote: > We don't update ewma rx buf size in the case of XDP. This will lead > underestimation of rx buf size which causes host to produce more than > one buffers. This will greatly increase the possibility of XDP page > linearization. > > Cc: John Fastabend <john.r.fastab...@intel.com> > Signed-off-by: Jason Wang <jasow...@redhat.com> > --- > drivers/net/virtio_net.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 0778dc8..77ae358 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -584,10 +584,12 @@ static struct sk_buff *receive_mergeable(struct > net_device *dev, > put_page(page); > head_skb = page_to_skb(vi, rq, xdp_page, > 0, len, PAGE_SIZE); > + ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len); > return head_skb; > } > break; > case XDP_TX: > + ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len); > if (unlikely(xdp_page != page)) > goto err_xdp; > rcu_read_unlock(); > @@ -596,6 +598,7 @@ static struct sk_buff *receive_mergeable(struct > net_device *dev, > default: > if (unlikely(xdp_page != page)) > __free_pages(xdp_page, 0); > + ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len); > goto err_xdp; > } > } >
Looks needed although I guess it will only be the case with MTU > ETH_DATA_LEN because of the clamp in get_mergeable_buf_len(). Although XDP setup allows MTU up to page_size - hdr so certainly will happen with ~MTU > 1500. I need to add some various MTU tests to my setup. Acked-by: John Fastabend <john.r.fastab...@intel.com>
