Messages in this thread | | | Subject | Re: [PATCH net-next 0/2] virtio-net: re enable XDP_REDIRECT for mergeable buffer | From | Jason Wang <> | Date | Thu, 1 Mar 2018 17:23:37 +0800 |
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On 2018年03月01日 17:10, Jesper Dangaard Brouer wrote: > On Thu, 1 Mar 2018 11:19:03 +0800 > Jason Wang <jasowang@redhat.com> wrote: > >> This series tries to re-enable XDP_REDIRECT for mergeable buffer which >> was removed since commit 7324f5399b06 ("virtio_net: disable >> XDP_REDIRECT in receive_mergeable() case"). Main concerns are: >> >> - not enough tailroom was reserved which breaks cpumap > To address this at a more fundamental level, I would suggest that we/you > instead extend XDP to know it's buffers "frame" size/end. (The > assumption use to be, xdp_buff->data_hard_start + PAGE_SIZE, but > ixgbe+virtio_net broke that assumption). > > It should actually be fairly easy to implement: > * Simply extend xdp_buff with a "data_hard_end" pointer.
Right, and then cpumap can warn and drop packets with insufficient tailroom. But it should be a patch on top of this I think.
Thanks
> > Now cpumap is more safe... instead of crashing, it can now know/see when > it is safe to create an SKB using build_skb (could fallback to > dev_alloc_skb). >
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