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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B99AC433EF for ; Fri, 13 May 2022 04:34:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242215AbiEMEe5 (ORCPT ); Fri, 13 May 2022 00:34:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234970AbiEMEe4 (ORCPT ); Fri, 13 May 2022 00:34:56 -0400 Received: from mail-yw1-x1132.google.com (mail-yw1-x1132.google.com [IPv6:2607:f8b0:4864:20::1132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5CA95293B59 for ; Thu, 12 May 2022 21:34:55 -0700 (PDT) Received: by mail-yw1-x1132.google.com with SMTP id 00721157ae682-2ebf4b91212so78302257b3.8 for ; Thu, 12 May 2022 21:34:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=M5LVIDD5gSbyFht1+X/mFQns5ulxp5IA0wB9nApyU1U=; b=K4P8d7jWYS8WhCd5J+zAYdlsP0MY22mU3o8yhApu2acQBjxLztzAhCt5ejZ9u8gxX9 2pJ/ltILnLUsNz9yuCywLE3t0ZjPfwEIHoIjPsWmzg7HOBxEhGE1AP2yEkeu+UpD2VXl YgDpCzd1g5AcCtG1UbCi5yWznBGoUilmoai3kYTBBbeOrJtzF1SQAq+EuhR3h43M9l5h sX0IWeEMXMQvDTCPkBGDNET9+fVhKMl4IZ27/6QK/LdV7qwjvlPaAE6n7vJ2/LMBPlLW Y+B0VrMl3MTzuLBblX8OpVOQRifLqL/UJxc1R0XCnZ1tX/VAIe1Z1SCqj+9UDYUpHiCW DwJg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=M5LVIDD5gSbyFht1+X/mFQns5ulxp5IA0wB9nApyU1U=; b=A8cKu4LKa+f/bMbWIy4bDDfI365WF691oCZqsUa1m6vayLT162uFzhf/3INFWf/rSB m9zXFpEkHRb71HZVxMGctSfv4NVx/HYWFOZEctNsyB5XzltjNlD04drOXi5krpeAddBv qynsL+GnAFFYHqptv53MwLWCnj2EREWOgLRRu6Y0DxAGJbyblWyN+Nw3ZzOb/h4mQ2pr k3zzvn7masrwMQJySZZqN2YgOpWvrGPiYsedXIYf76okwAUJCuSGflRkKn0l7i+4DCg6 FrexQ/n4UZwuw7TXu5Xci+V2/yio3lF/thO3hSkQlQVesKMkoDAt7arY3ICHDksCtVYz wqsA== X-Gm-Message-State: AOAM530H2KipOwMDdWek5ysHhzzntMTcEq1uLLmbqniQ7fmcZh8uytoU tKGNXGvn38Y0rbWWzUY9Nb97RD3rJVjUo/k8bY420WZVdcCx6Xvo X-Google-Smtp-Source: ABdhPJy/yJmHLJFlznImD7j1VdctCiEWW7WgK8EgIYjBKPFN+CGSp2gYKEzhOrtrF0O6kPyZ0a7qCA9NkzSngd+z/X4= X-Received: by 2002:a81:234b:0:b0:2f8:4082:bbd3 with SMTP id j72-20020a81234b000000b002f84082bbd3mr3666109ywj.47.1652416494290; Thu, 12 May 2022 21:34:54 -0700 (PDT) MIME-Version: 1.0 References: <20220510033219.2639364-1-eric.dumazet@gmail.com> <20220510033219.2639364-14-eric.dumazet@gmail.com> <20220512084023.tgjcecnu6vfuh7ry@LT-SAEEDM-5760.attlocal.net> <51bc118ff452c42fef489818422f278ab79e6dd4.camel@redhat.com> <20220513042955.rnid4776hwp556vr@fedora> In-Reply-To: <20220513042955.rnid4776hwp556vr@fedora> From: Eric Dumazet Date: Thu, 12 May 2022 21:34:43 -0700 Message-ID: Subject: Re: [PATCH v6 net-next 13/13] mlx5: support BIG TCP packets To: Saeed Mahameed Cc: Paolo Abeni , Eric Dumazet , "David S . Miller" , Jakub Kicinski , netdev , Alexander Duyck , Coco Li , Tariq Toukan , Leon Romanovsky Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, May 12, 2022 at 9:29 PM Saeed Mahameed wrote: > > On 12 May 11:02, Paolo Abeni wrote: > >On Thu, 2022-05-12 at 01:40 -0700, Saeed Mahameed wrote: > >> On 09 May 20:32, Eric Dumazet wrote: > >> > From: Coco Li > >> > > >> > mlx5 supports LSOv2. > >> > > >> > IPv6 gro/tcp stacks insert a temporary Hop-by-Hop header > >> > with JUMBO TLV for big packets. > >> > > >> > We need to ignore/skip this HBH header when populating TX descriptor. > >> > > >> > >> Sorry i didn't go through all the documentations or previous discussions, > >> please bare with me, so why not clear HBH just before calling the > >> driver xmit ndo ? > > > >I guess this way is more efficient: the driver copies IP hdr and TCP > >hdr directly in the correct/final location into the tx descriptor, > >otherwise the caller would have to memmove L2/L3 just before the driver > >copies them again. > >> > > memmove(sizeof(L2/L3)) is not that bad when done only every 64KB+. > it's going to be hard to repeat this and maintain this across all drivers > only to get this micro optimization that I doubt it will be even measurable. We prefer not changing skb->head, this would break tcpdump. Surely calling skb_cow_head() would incur a cost. As I suggested, we can respin the series without the mlx5 patch, this is totally fine for us, if we can avoid missing 5.19 train.