From: Annika Wickert <annika.wickert@exaring.de>
To: Sven Eckelmann <sven@narfation.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Cc: "b.a.t.m.a.n@lists.open-mesh.org"
<b.a.t.m.a.n@lists.open-mesh.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] vxlan: Add needed_headroom for lower device
Date: Thu, 26 Nov 2020 18:19:49 +0000 [thread overview]
Message-ID: <8257B44A-FA67-40D1-BC5E-C8AB82E42BFE@exaring.de> (raw)
In-Reply-To: <20201126125247.1047977-1-sven@narfation.org>
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
next prev parent reply other threads:[~2020-11-26 18:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-26 12:52 [PATCH 1/2] vxlan: Add needed_headroom for lower device Sven Eckelmann
2020-11-26 12:52 ` [PATCH 2/2] vxlan: Copy needed_tailroom from lowerdev Sven Eckelmann
2020-11-26 18:19 ` Annika Wickert [this message]
2020-12-01 2:34 ` [PATCH 1/2] vxlan: Add needed_headroom for lower device Jakub Kicinski
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