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@xxxxxxxxxx> 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 cpumapTo 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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