On Thu, 26 Nov 2020 13:52:46 +0100 Sven Eckelmann wrote:
It was observed that sending data via batadv over vxlan (on top of wireguard) reduced the performance massively compared to raw ethernet or batadv on raw ethernet. A check of perf data showed that the vxlan_build_skb was calling all the time pskb_expand_head to allocate enough headroom for:
min_headroom = LL_RESERVED_SPACE(dst->dev) + dst->header_len + VXLAN_HLEN + iphdr_len;
But the vxlan_config_apply only requested needed headroom for:
lowerdev->hard_header_len + VXLAN6_HEADROOM or VXLAN_HEADROOM
So it completely ignored the needed_headroom of the lower device. The first caller of net_dev_xmit could therefore never make sure that enough headroom was allocated for the rest of the transmit path.
Cc: Annika Wickert annika.wickert@exaring.de Signed-off-by: Sven Eckelmann sven@narfation.org
Applied both, thanks!