| Message ID | 20201126125247.1047977-1-sven@narfation.org (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [1/2] vxlan: Add needed_headroom for lower device | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Guessed tree name to be net-next |
| netdev/subject_prefix | warning | Target tree name not specified in the subject |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 1 this patch: 1 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 7 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 1 this patch: 1 |
| netdev/header_inline | success | Link |
| netdev/stable | success | Stable not CCed |
Tested-by: Annika Wickert <aw@awlnx.space> On 26.11.20, 13:53, "Sven Eckelmann" <sven@narfation.org> 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> --- drivers/net/vxlan.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 236fcc55a5fd..25b5b5a2dfea 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -3799,6 +3799,7 @@ static void vxlan_config_apply(struct net_device *dev, dev->gso_max_segs = lowerdev->gso_max_segs; needed_headroom = lowerdev->hard_header_len; + needed_headroom += lowerdev->needed_headroom; max_mtu = lowerdev->mtu - (use_ipv6 ? VXLAN6_HEADROOM : VXLAN_HEADROOM); -- 2.29.2
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!
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 236fcc55a5fd..25b5b5a2dfea 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -3799,6 +3799,7 @@ static void vxlan_config_apply(struct net_device *dev, dev->gso_max_segs = lowerdev->gso_max_segs; needed_headroom = lowerdev->hard_header_len; + needed_headroom += lowerdev->needed_headroom; max_mtu = lowerdev->mtu - (use_ipv6 ? VXLAN6_HEADROOM : VXLAN_HEADROOM);
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> --- drivers/net/vxlan.c | 1 + 1 file changed, 1 insertion(+)