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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE6B8C433F5 for ; Tue, 26 Oct 2021 14:52:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C46D60F70 for ; Tue, 26 Oct 2021 14:52:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236194AbhJZOzN (ORCPT ); Tue, 26 Oct 2021 10:55:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33076 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236058AbhJZOzM (ORCPT ); Tue, 26 Oct 2021 10:55:12 -0400 Received: from mail-ot1-x334.google.com (mail-ot1-x334.google.com [IPv6:2607:f8b0:4864:20::334]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10D94C061745 for ; Tue, 26 Oct 2021 07:52:49 -0700 (PDT) Received: by mail-ot1-x334.google.com with SMTP id v2-20020a05683018c200b0054e3acddd91so17621808ote.8 for ; Tue, 26 Oct 2021 07:52:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=ggIEajTIJZ9pjb6h9Yfl1Q1AiXRfxaF8TetiL4XvNK8=; b=IzMkdpnUjiU/ewuxiOmXDbUad1TDMFqKLqrr6FjGAMb5eC6YGkgZHg2XaNgF5QD/ko ettt9HZOrd9VYtf23Nrsq4cvdQUIHhbPUHlqOLaM79BvbVdNFGIW5LEf5d0gTyC00YLp 0qrlfk6s+aOGD/SBUmzaajkayAxzWJgjpucN3V/BJpDYwxa6UgX0/c26q+pf9nFO1qbM pkPPutpktak5YpM1sPcsjnVATWlmIpx2zDDSJBCbrpj8s55UdxIoLWJzeq285eKOj/Y7 XmooQRBWmCApFkJjuelQEOLtZ01O2FoY6gG0iJezdNob2GcpfLmOGBP2JzMX98+8S0pj 28yQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=ggIEajTIJZ9pjb6h9Yfl1Q1AiXRfxaF8TetiL4XvNK8=; b=4gEzgL55sYJKOUiNcxIaKaDiEH2KxQMWVCTl7JME5D+LCIoHVM5nM8LCEdmGCty03C ugVvtdxCm/lBFqC0f9tRyPXJEiy/LwarraLUHC97yDHjpEXrrOyoQdTekDVuOsuw/rjR U8ZYDltPYNJuUoCatYhbOnoNvBOypIhUjPJvvHIp2ua3+nR0amW/9qCa7awLdmP04m1f L1aoN/jt2+Xr+zdtijWKQzZeUW38NyQar8YRJNYQJH9v/SKBwox9foFX1Wf5Lb4Z9QXc nzY9CY405uGs8tpVBqsl45/BQnwCMwxLCES1ROQJQ78HVngHwCZ42J95+An9hlHVegDG cSyg== X-Gm-Message-State: AOAM532An+iwPkYr2fS8ghnQjoxRfJI5zyA/VKFsaL+BaTynWb/+IZwB 8L+7cYkufhuJPUeinCATwdg= X-Google-Smtp-Source: ABdhPJxDNdhFkLexor9deO91MCnn0B7gcgw8pTuv4L7OoErJOro9E/u4RaLLaCK70p+ozq3EYSPFvg== X-Received: by 2002:a9d:7153:: with SMTP id y19mr19903333otj.41.1635259968389; Tue, 26 Oct 2021 07:52:48 -0700 (PDT) Received: from [172.16.0.2] ([8.48.134.30]) by smtp.googlemail.com with ESMTPSA id bc41sm4199681oob.2.2021.10.26.07.52.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 26 Oct 2021 07:52:47 -0700 (PDT) Message-ID: <4dd34a92-bfcf-27ad-2d32-c93f7a9082a9@gmail.com> Date: Tue, 26 Oct 2021 08:52:45 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.2.1 Subject: Re: [RESEND PATCH v7 2/3] net: ndisc: introduce ndisc_evict_nocarrier sysctl parameter Content-Language: en-US To: James Prestwood , netdev@vger.kernel.org Cc: davem@davemloft.net, kuba@kernel.org, corbet@lwn.net, yoshfuji@linux-ipv6.org, dsahern@kernel.org, roopa@nvidia.com, daniel@iogearbox.net, vladimir.oltean@nxp.com, idosch@nvidia.com, nikolay@nvidia.com, yajun.deng@linux.dev, zhutong@amazon.com, johannes@sipsolutions.net, jouni@codeaurora.org References: <20211025164547.1097091-1-prestwoj@gmail.com> <20211025164547.1097091-3-prestwoj@gmail.com> From: David Ahern In-Reply-To: <20211025164547.1097091-3-prestwoj@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 10/25/21 10:45 AM, James Prestwood wrote: > In most situations the neighbor discovery cache should be cleared on a > NOCARRIER event which is currently done unconditionally. But for wireless > roams the neighbor discovery cache can and should remain intact since > the underlying network has not changed. > > This patch introduces a sysctl option ndisc_evict_nocarrier which can > be disabled by a wireless supplicant during a roam. This allows packets > to be sent after a roam immediately without having to wait for > neighbor discovery. > > A user reported roughly a 1 second delay after a roam before packets > could be sent out (note, on IPv4). This delay was due to the ARP > cache being cleared. During testing of this same scenario using IPv6 > no delay was noticed, but regardless there is no reason to clear > the ndisc cache for wireless roams. > > Signed-off-by: James Prestwood > --- > Documentation/networking/ip-sysctl.rst | 9 +++++++++ > include/linux/ipv6.h | 1 + > include/uapi/linux/ipv6.h | 1 + > net/ipv6/addrconf.c | 12 ++++++++++++ > net/ipv6/ndisc.c | 12 +++++++++++- > 5 files changed, 34 insertions(+), 1 deletion(-) > Reviewed-by: David Ahern