From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 096D6C63777 for ; Thu, 26 Nov 2020 12:53:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9777221D40 for ; Thu, 26 Nov 2020 12:53:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=narfation.org header.i=@narfation.org header.b="P8W/Ymhc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389727AbgKZMxW (ORCPT ); Thu, 26 Nov 2020 07:53:22 -0500 Received: from dvalin.narfation.org ([213.160.73.56]:39308 "EHLO dvalin.narfation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389266AbgKZMxV (ORCPT ); Thu, 26 Nov 2020 07:53:21 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=narfation.org; s=20121; t=1606395197; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=u9brxP8N0Zad68RDWJ6eU6Uvj+b8EOgYlFMeuq6xuxs=; b=P8W/YmhcdPLxb73c6tYExpaaeX0D3QinuxJz9eVJOdwWiECUgQI4YSQGS1zE0Fha1CiIMZ fTIu8AYvOnPYsbK6ULiGhmT3WE76Or/i/X40vq40v2+Wy+ZRQ11mWFs1MYcIrP+vb/gowU Xlg8GATDkz+tutA7cotNBETv8pL+nbU= From: Sven Eckelmann To: netdev@vger.kernel.org Cc: b.a.t.m.a.n@lists.open-mesh.org, linux-kernel@vger.kernel.org, Sven Eckelmann , Annika Wickert Subject: [PATCH 1/2] vxlan: Add needed_headroom for lower device Date: Thu, 26 Nov 2020 13:52:46 +0100 Message-Id: <20201126125247.1047977-1-sven@narfation.org> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Signed-off-by: Sven Eckelmann --- 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