Re: [PATCH net 1/2] geneve, vxlan: Don't check skb_dst() twice
From: Nicolas Dichtel <hidden>
Date: 2018-10-15 20:09:32
Le 15/10/2018 à 13:08, Stefano Brivio a écrit :
On Mon, 15 Oct 2018 12:19:41 +0200 Nicolas Dichtel [off-list ref] wrote:quoted
Le 12/10/2018 à 23:53, Stefano Brivio a écrit :quoted
Commit f15ca723c1eb ("net: don't call update_pmtu unconditionally") avoids that we try updating PMTU for a non-existent destination, but didn't clean up cases where the check was already explicit. Drop those redundant checks.Yes, I leave them to avoid calculating the new mtu value when not needed. We are in the xmit path.Before 2/2 of this series, though, we call skb_dst_update_pmtu() (and in turn dst->ops->update_pmtu()) for *every* packet with a dst, which
Not if dst is of type md_dst_ops.
I'd dare saying is by far the most common case. Besides, 2/2 needs anyway to calculate the MTU to fix a bug. So I think this is a vast improvement overall.
Fair point.