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=-5.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 A8382C47095 for ; Wed, 7 Oct 2020 16:38:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4DACD2176B for ; Wed, 7 Oct 2020 16:38:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="tRTmiTM9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727698AbgJGQi6 (ORCPT ); Wed, 7 Oct 2020 12:38:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51804 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726702AbgJGQi6 (ORCPT ); Wed, 7 Oct 2020 12:38:58 -0400 Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 714F9C061755; Wed, 7 Oct 2020 09:38:58 -0700 (PDT) Received: by mail-pl1-x643.google.com with SMTP id h2so1257608pll.11; Wed, 07 Oct 2020 09:38:58 -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=eleMNIQb7gHtATh1xUcvTG7HUCdElenFbTTcPyhDSnc=; b=tRTmiTM9jwWvOTzvDET4KhQtnAoz2ZUQqrBD5kuSR/B1ypVTwD/0yixJDGXLWwl4qo CPED75gI9buKhnlEwn4nK0ZJTVeIgra8iUeuIId/cWA3kfKZPlqtxHWKd5UdIlczxY0l IHKK9tUf7becvMeUDXnTMFzipMoVuArErHNuFRr1TcGc7+rSSOjG3vsIpGuCKIEnL55D +T/nc9ugENV/4avggtpnWNKbmhAOD5ffcbx4Vm8hZPxp/KPr2Nk3Mh7BgcqqW+EVD3U3 wy79Nipf9NtEkwFW8AisuuUxd2uBx2EOHS+FQzIjK9PhPFOLNRwYSj8dAAI7jeAZ6zfp SIQg== 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=eleMNIQb7gHtATh1xUcvTG7HUCdElenFbTTcPyhDSnc=; b=RzfPQUQLSZ804+VXPJWx2CtwbO420eGYHrvc65SfbKpcuhOxUJUJxoLaliGe44L4++ 7H5/HIyBqYqyZKyiXIWmxdavB+ddLGYQpOjIJgrQ9Q2GSP2LXJdAHtm9FzEJ5MGgVuDt pPuHstdrQWZUeQ/S1x0lJlWYRWDv8LOMqWOasoqE2PbVHc6uFRVCUyjB/JFWIuik0CVZ TnIOYdQ2mRwJCD//ys288SnU0PtJrTacQIDu4hqpDOh3s6SIXctFbFRrtLRHYwwR9IQd Y0snjFPxWhDHk6jdxfKP16Z6N79lvcfwjEmrGu6b10jjg51Y1PUJYT+PJ9H/TLDzfI5X EtSg== X-Gm-Message-State: AOAM530uCouKhSWcbfKqckyOyc9q6XrFjyQ1GjmKrNC8B4UJy8abApEq bJCHCvqkC2JBRDnZZTOEJgo= X-Google-Smtp-Source: ABdhPJz0GT8qO12nu0i8QQACgcARFrYLfleCdraKFW8xrzsUprTU5cx8o0DOy0ROBpeZpWg/j5/UoQ== X-Received: by 2002:a17:902:6ac7:b029:d3:9c6b:9311 with SMTP id i7-20020a1709026ac7b02900d39c6b9311mr3553394plt.0.1602088738055; Wed, 07 Oct 2020 09:38:58 -0700 (PDT) Received: from Davids-MacBook-Pro.local ([72.164.175.30]) by smtp.googlemail.com with ESMTPSA id u18sm4142621pgk.18.2020.10.07.09.38.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 07 Oct 2020 09:38:57 -0700 (PDT) Subject: Re: [PATCH bpf-next V1 2/6] bpf: bpf_fib_lookup return MTU value as output when looked up To: Jesper Dangaard Brouer , =?UTF-8?Q?Maciej_=c5=bbenczykowski?= Cc: bpf , Linux NetDev , Daniel Borkmann , Alexei Starovoitov , Lorenz Bauer , Shaun Crampton , Lorenzo Bianconi , Marek Majkowski , John Fastabend , Jakub Kicinski , David Ahern References: <160200013701.719143.12665708317930272219.stgit@firesoul> <160200017655.719143.17344942455389603664.stgit@firesoul> <20201007094228.5919998b@carbon> From: David Ahern Message-ID: <23e087e7-066c-2228-8df7-3a6b81ad2ba0@gmail.com> Date: Wed, 7 Oct 2020 09:38:56 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: <20201007094228.5919998b@carbon> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 10/7/20 12:42 AM, Jesper Dangaard Brouer wrote: > > The struct bpf_fib_lookup is exactly 1 cache-line (64 bytes) for > performance reasons. I do believe that it can be extended, as Ahern > designed the BPF-helper API cleverly via a plen (detail below signature). Yes, I kept it to 64B for performance reasons which is why most fields have 1 value on input and another on output. Technically it can be extended, but any cost in doing so should be abosrbed by the new feature(s). Meaning, users just doing a fib lookup based on current API should not take a hit with the extra size.