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 10A0EC433EF for ; Mon, 27 Dec 2021 20:34:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232827AbhL0UeY (ORCPT ); Mon, 27 Dec 2021 15:34:24 -0500 Received: from mga05.intel.com ([192.55.52.43]:32592 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229843AbhL0UeX (ORCPT ); Mon, 27 Dec 2021 15:34:23 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1640637263; x=1672173263; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=iG1ggZ11L9JNjcVM2LtagDTWszVONzK5iQFTRN1NBe4=; b=Cf5UncOdawXp9ha85Ukg1xQKVxOHJNJO4CUUKUYH4u+mRipybY5m4UTs yU9EsLFPTltzonRXnKMplHluMy/V6+ZluyEooH7EcJZdSLpCM04TksCNd UgqzryOzWE1KG7qXrdVHdFHvcDUyNyh8S0P/B4nlQfglonDY6p3c1wxla rxWfcieLfItHqcM9g7nN+HxApGHiDXfFaY9B9BkPa1VwR/2kpMvXcs4Ia 0h/Cp7nIEft0aEShUlZsEg1oJT54Nka3y19R5FqJQv9PBZGaXbscnr7qc lg+qb4cpi56v+Bh2Lvot47BYDYuULjqxa9VkEn+9V+Td/cUVV05Lj9iFm g==; X-IronPort-AV: E=McAfee;i="6200,9189,10210"; a="327592401" X-IronPort-AV: E=Sophos;i="5.88,240,1635231600"; d="scan'208";a="327592401" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Dec 2021 12:34:23 -0800 X-IronPort-AV: E=Sophos;i="5.88,240,1635231600"; d="scan'208";a="523405879" Received: from krausnex-mobl.ger.corp.intel.com (HELO [10.255.195.237]) ([10.255.195.237]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Dec 2021 12:34:18 -0800 Message-ID: Date: Mon, 27 Dec 2021 22:34:10 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.3.2 Subject: Re: [Intel-wired-lan] [PATCH v4 net-next 6/9] igc: don't reserve excessive XDP_PACKET_HEADROOM on XSK Rx to skb Content-Language: en-US To: Alexander Lobakin , intel-wired-lan@lists.osuosl.org Cc: Song Liu , Jesper Dangaard Brouer , Daniel Borkmann , Yonghong Song , Martin KaFai Lau , John Fastabend , Alexei Starovoitov , Andrii Nakryiko , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , netdev@vger.kernel.org, Jakub Kicinski , KP Singh , bpf@vger.kernel.org, "David S. Miller" , linux-kernel@vger.kernel.org References: <20211208140702.642741-1-alexandr.lobakin@intel.com> <20211208140702.642741-7-alexandr.lobakin@intel.com> From: "Kraus, NechamaX" In-Reply-To: <20211208140702.642741-7-alexandr.lobakin@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 12/8/2021 16:06, Alexander Lobakin wrote: > {__,}napi_alloc_skb() allocates and reserves additional NET_SKB_PAD > + NET_IP_ALIGN for any skb. > OTOH, igc_construct_skb_zc() currently allocates and reserves > additional `xdp->data_meta - xdp->data_hard_start`, which is about > XDP_PACKET_HEADROOM for XSK frames. > There's no need for that at all as the frame is post-XDP and will > go only to the networking stack core. > Pass the size of the actual data only (+ meta) to > __napi_alloc_skb() and don't reserve anything. This will give > enough headroom for stack processing. > Also, net_prefetch() xdp->data_meta and align the copy size to > speed-up memcpy() a little and better match igc_costruct_skb(). > > Fixes: fc9df2a0b520 ("igc: Enable RX via AF_XDP zero-copy") > Signed-off-by: Alexander Lobakin > Reviewed-by: Michal Swiatkowski > --- > drivers/net/ethernet/intel/igc/igc_main.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > Tested-by: Nechama Kraus