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 C7457C04FDE for ; Fri, 9 Dec 2022 08:12:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229640AbiLIIME (ORCPT ); Fri, 9 Dec 2022 03:12:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230057AbiLIIMA (ORCPT ); Fri, 9 Dec 2022 03:12:00 -0500 Received: from mx05lb.world4you.com (mx05lb.world4you.com [81.19.149.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C1443FBAA; Fri, 9 Dec 2022 00:11:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=engleder-embedded.com; s=dkim11; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=XC5/MMmtJdf0hJ+jzFyQ1kSBjAfC/+KimqL3WG7xuN4=; b=xd4cVeAfhTfNvV18S8zqs6Dk0v LSseYN5J30XzIdjur/UL/bnzQLhtPtk6VuUXLHCQ1/rGJEIFMui3MmmT2QjbNd/aJEpKCHY5NJogH hT//ARVi+vli36/dFysFvZp26sySNzBhCNE8G3SU0X8gvNT46w4N8YSYsb+Im+f4jS10=; Received: from [88.117.53.17] (helo=[10.0.0.160]) by mx05lb.world4you.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1p3YU5-0001XO-QT; Fri, 09 Dec 2022 09:11:53 +0100 Message-ID: <82b5acef-6d2f-6631-326e-6ec12b2257ec@engleder-embedded.com> Date: Fri, 9 Dec 2022 09:11:53 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH net-next v2 5/6] tsnep: Add RX queue info for XDP support Content-Language: en-US To: Saeed Mahameed Cc: Maciej Fijalkowski , netdev@vger.kernel.org, bpf@vger.kernel.org, davem@davemloft.net, kuba@kernel.org, edumazet@google.com, pabeni@redhat.com, ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com References: <20221208054045.3600-1-gerhard@engleder-embedded.com> <20221208054045.3600-6-gerhard@engleder-embedded.com> <45d4de61-9a6e-be55-5a00-9e7ff464f4be@engleder-embedded.com> From: Gerhard Engleder In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-AV-Do-Run: Yes Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 09.12.22 01:53, Saeed Mahameed wrote: > On 08 Dec 21:32, Gerhard Engleder wrote: >> On 08.12.22 13:59, Maciej Fijalkowski wrote: >>> On Thu, Dec 08, 2022 at 06:40:44AM +0100, Gerhard Engleder wrote: >>>> Register xdp_rxq_info with page_pool memory model. This is needed for >>>> XDP buffer handling. >>>> >>>> Signed-off-by: Gerhard Engleder >>>> --- >>>>  drivers/net/ethernet/engleder/tsnep.h      |  5 ++-- >>>>  drivers/net/ethernet/engleder/tsnep_main.c | 34 +++++++++++++++++----- >>>>  2 files changed, 30 insertions(+), 9 deletions(-) >>>> >>>> diff --git a/drivers/net/ethernet/engleder/tsnep.h >>>> b/drivers/net/ethernet/engleder/tsnep.h >>>> index 0e7fc36a64e1..70bc133d4a9d 100644 >>>> --- a/drivers/net/ethernet/engleder/tsnep.h >>>> +++ b/drivers/net/ethernet/engleder/tsnep.h >>>> @@ -127,6 +127,7 @@ struct tsnep_rx { >>>>      u32 owner_counter; >>>>      int increment_owner_counter; >>>>      struct page_pool *page_pool; >>>> +    struct xdp_rxq_info xdp_rxq; >>> >>> this occupies full cacheline, did you make sure that you don't break >>> tsnep_rx layout with having xdp_rxq_info in the middle of the way? >> >> Actually I did no cacheline optimisation for this structure so far. >> I saw that igb/igc put xdp_rxq_info to the end. Is this best practice >> to prevent other variables in the same cacheline of xdp_rxq? > > a rule of thumb, organize the structure in the same order they are > being accessed in the data path.. but this doesn't go without saying you > need to do some layout testing via pahole for example.. > It's up to you and the maintainer of this driver to decide how critical > this > is. > > Reviewed-by: Saeed Mahameed Thanks for the clarification, I will think about it. I wrote the driver and I'm responsible to keep it working. Is this equal to being the maintainer? Thanks for the review! Gerhard