On 12/18/2017 07:20 AM, Xin Long wrote:
Unlike ip tunnels, now vxlan doesn't do any pmtu update for
upper dst pmtu, even if it doesn't match the lower dst pmtu
any more.
The problem can be reproduced when reducing the vxlan lower
dev's pmtu when running netperf. In jianlin's testing, the
performance went to 1/7 of the previous.
This patch is to update the upper dst pmtu to match the lower
dst pmtu on tx path so that packets can be sent out even when
lower dev's pmtu has been changed.
It also works for metadata dst.
Sorry for resurrecting the conversation, but what exactly was meant by
this "works metadata dst" remark? I am currently having kernel crashes
related to ops->update_pmtu == NULL on VXLAN xmit and I am using tunnel
metadata set by act_tunnel_key. Before this patch, it was OK.
My first thought was to add `if (ops->update_pmtu != NULL)`, but it
appears some thought was given to this. Or maybe md_dst_ops should have
update pmtu?
Thanks, Roman Kapl
