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=-7.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 9DF4FC43461 for ; Fri, 4 Sep 2020 07:36:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7692A20722 for ; Fri, 4 Sep 2020 07:36:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726597AbgIDHgA (ORCPT ); Fri, 4 Sep 2020 03:36:00 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:40853 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726089AbgIDHf7 (ORCPT ); Fri, 4 Sep 2020 03:35:59 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-425-8I2tKuALN4GdHpuv0fjZjQ-1; Fri, 04 Sep 2020 03:35:55 -0400 X-MC-Unique: 8I2tKuALN4GdHpuv0fjZjQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A0137801AEE; Fri, 4 Sep 2020 07:35:53 +0000 (UTC) Received: from carbon (unknown [10.40.208.42]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0224A18B59; Fri, 4 Sep 2020 07:35:43 +0000 (UTC) Date: Fri, 4 Sep 2020 09:35:42 +0200 From: Jesper Dangaard Brouer To: Lorenzo Bianconi Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, davem@davemloft.net, lorenzo.bianconi@redhat.com, echaudro@redhat.com, sameehj@amazon.com, kuba@kernel.org, john.fastabend@gmail.com, daniel@iogearbox.net, ast@kernel.org, shayagr@amazon.com, brouer@redhat.com, intel-wired-lan Subject: Re: [PATCH v2 net-next 2/9] xdp: initialize xdp_buff mb bit to 0 in all XDP drivers Message-ID: <20200904093542.4dc43682@carbon> In-Reply-To: <05822dfe200c5d581d6a6cad89c1b63bb7a1c566.1599165031.git.lorenzo@kernel.org> References: <05822dfe200c5d581d6a6cad89c1b63bb7a1c566.1599165031.git.lorenzo@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, 3 Sep 2020 22:58:46 +0200 Lorenzo Bianconi wrote: > diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c > index 0b675c34ce49..20c8fd3cd4a3 100644 > --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c > +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c > @@ -2298,6 +2298,7 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, > #if (PAGE_SIZE < 8192) > xdp.frame_sz = ixgbe_rx_frame_truesize(rx_ring, 0); > #endif > + xdp.mb = 0; > > while (likely(total_rx_packets < budget)) { > union ixgbe_adv_rx_desc *rx_desc; In this ixgbe driver you are smart and init the xdp.mb bit outside the (like xdp.frame_sz, when frame_sz is constant). This is a nice optimization, but the driver developer that adds XDP multi-buffer support must remember to reset it. The patch itself is okay, it is just something to keep in-mind when reviewing/changing drivers. -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer