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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 5BFABC38A2A for ; Fri, 8 May 2020 15:04:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E7442173E for ; Fri, 8 May 2020 15:04:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Fpb39XBC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727874AbgEHPEB (ORCPT ); Fri, 8 May 2020 11:04:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726767AbgEHPEA (ORCPT ); Fri, 8 May 2020 11:04:00 -0400 Received: from mail-qt1-x841.google.com (mail-qt1-x841.google.com [IPv6:2607:f8b0:4864:20::841]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 92148C061A0C for ; Fri, 8 May 2020 08:04:00 -0700 (PDT) Received: by mail-qt1-x841.google.com with SMTP id g16so705464qtp.11 for ; Fri, 08 May 2020 08:04:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=QeoWvumS9qi1Gy3H41jW6MV5mxSMg6K3dWIQfbfT1Yc=; b=Fpb39XBCNv95qUlSExlDtCMcEDHwu4OoU0W2XMmwNNeh7IxItgQjwUkeAKE/aOrub8 IBp59G59+EeX2j0ZZsapFOh2PiWELw7GztOL4h4PXbPigjMbWTtcBLphDucK6f6VR7c4 gZKAhrR7GsNHUGrN7QjbTs8zRdnUslwk6mGVJvIoWEBiZ4LfKt8K2SCx8bXxs5e9V6If Mjmbk8Cga80boOEj+6KfVG8iol3mpanjUu9mxBVWmkJqgT5JMu1e3Kki2nTdo04QtRlt eXSkPuSOF5Oj2PkmgNN5ncXPuSSkpCmdsMaTDsJ9iAGFYHhiirixCb8S9Ps0K4Yf0GYR W35Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=QeoWvumS9qi1Gy3H41jW6MV5mxSMg6K3dWIQfbfT1Yc=; b=fdVqChDyBORAt2eyjFxvQQZfwS08z6jcd85Ho+eXDsdLUAhmOazM8AEYWE3aMoROOp Ks4CVU9a72N6nHi+rMr2NcCeN+z2PfS8xBOUe0/v5PU+KOMtzMYbWTdvmCCi1bYemi0w XpynGvtj11Nn0dSSRqKbjL3c/VOwjBHdEdhjpzlVu7RV9aN7Wj4O4sq5uN8odIvzAbHQ mXJFhvYcfunHKL/dCZyaD2JW9k/8bW93FS4f56MGvprOqOQsclWf3NSaLtNN7Qy8duED v1lt/kOvDoeJ+CiqWnIGP+nkVVXEdT/S36GDkUqHHbfECP17j1FiGX+yKAcx3mH9Lb1f 5Ncw== X-Gm-Message-State: AGi0Pua80M60FCs5gI+3x/G1A66LP/ghL7jLbjtVXtga/g+IdzmMjewJ aBm2UcpBqsixRwBPhIuzMkM= X-Google-Smtp-Source: APiQypJdCPhMBkOJ8TR22e30bgrMozKTo4YNjjnxgaayI4ZdVUFtvIkwPvfuhWcZlYoio4K1RDxU4g== X-Received: by 2002:ac8:2f15:: with SMTP id j21mr3612458qta.259.1588950239851; Fri, 08 May 2020 08:03:59 -0700 (PDT) Received: from ?IPv6:2601:282:803:7700:c09e:cbdc:b4a2:7243? ([2601:282:803:7700:c09e:cbdc:b4a2:7243]) by smtp.googlemail.com with ESMTPSA id t15sm1669550qtc.64.2020.05.08.08.03.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 08 May 2020 08:03:59 -0700 (PDT) Subject: Re: [PATCH net-next] ipv6: use DST_NOCOUNT in ip6_rt_pcpu_alloc() To: Eric Dumazet , Eric Dumazet , "David S . Miller" Cc: netdev , Martin KaFai Lau , David Ahern , Wei Wang , =?UTF-8?Q?Maciej_=c5=bbenczykowski?= References: <20200508143414.42022-1-edumazet@google.com> <362c2030-6e7f-512d-4285-d904b4a433b6@gmail.com> From: David Ahern Message-ID: <92c6ab11-3022-a01a-95db-13f6da8637cc@gmail.com> Date: Fri, 8 May 2020 09:03:57 -0600 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 5/8/20 8:43 AM, Eric Dumazet wrote: > This patch can be backported without any pains ;) sure, but you tagged it as net-next, not net. > > Getting rid of limits, even for exceptions ? Running through where dst entries are created in IPv6: 1. pcpu cache 2. uncached_list 3. exceptions like pmtu and redirect All of those match IPv4 and as I recall IPv4 does not have any limits, even on exceptions and redirect. If IPv4 does not have limits, why should IPv6? And if the argument is uncontrolled memory consumption, is there an expectation that IPv6 generates more exceptions? My argument really just boils down to consistency between them. IPv4 does not use DST_NOCOUNT, so why put that burden on v6?