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=-5.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 9EA1AC28CBC for ; Wed, 6 May 2020 08:21:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7B857206E6 for ; Wed, 6 May 2020 08:21:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="OgYb0Kwv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728920AbgEFIV3 (ORCPT ); Wed, 6 May 2020 04:21:29 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:31592 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728371AbgEFIV3 (ORCPT ); Wed, 6 May 2020 04:21:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588753288; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nF+0VU5uQHo07GYFoGqtLNbg64uaIEB/qw6oVIMZLHo=; b=OgYb0KwvGTV8a2ylKpntvvLVomBOVTojFUiLGqIHZV5Q62X3qxI67gzZjkwtcWIl2EjkiY lR4GFCgK70vXUUNMscsEuM030E26aXN9ZMf/h17kXERH5FSt78To8hbOrSqrqhJtCrvUEE OFWk3JwLLkqTUCuEtarJuKDqc/pMuPk= 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-208-wJzohBH7M3qY_BjjNFOlpA-1; Wed, 06 May 2020 04:21:26 -0400 X-MC-Unique: wJzohBH7M3qY_BjjNFOlpA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 315A745F; Wed, 6 May 2020 08:21:25 +0000 (UTC) Received: from [10.72.13.165] (ovpn-13-165.pek2.redhat.com [10.72.13.165]) by smtp.corp.redhat.com (Postfix) with ESMTP id 30289579AD; Wed, 6 May 2020 08:21:17 +0000 (UTC) Subject: Re: [PATCH net-next 2/2] virtio-net: fix the XDP truesize calculation for mergeable buffers To: "Michael S. Tsirkin" Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, Jesper Dangaard Brouer References: <20200506061633.16327-1-jasowang@redhat.com> <20200506061633.16327-2-jasowang@redhat.com> <20200506033259-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: <789fc6e6-9667-a609-c777-a9b1fed72f41@redhat.com> Date: Wed, 6 May 2020 16:21:15 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200506033259-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/5/6 =E4=B8=8B=E5=8D=883:37, Michael S. Tsirkin wrote: > On Wed, May 06, 2020 at 02:16:33PM +0800, Jason Wang wrote: >> We should not exclude headroom and tailroom when XDP is set. So this >> patch fixes this by initializing the truesize from PAGE_SIZE when XDP >> is set. >> >> Cc: Jesper Dangaard Brouer >> Signed-off-by: Jason Wang > Seems too aggressive, we do not use up the whole page for the size. > > > For XDP yes, we do: static unsigned int get_mergeable_buf_len(struct receive_queue *rq, =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2= =A0 =C2=A0=C2=A0=C2=A0 =C2=A0 struct ewma_pkt_len *avg_pkt_len, =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2= =A0 =C2=A0=C2=A0=C2=A0 =C2=A0 unsigned int room) { =C2=A0=C2=A0=C2=A0 const size_t hdr_len =3D sizeof(struct virtio_net_hdr= _mrg_rxbuf); =C2=A0=C2=A0=C2=A0 unsigned int len; =C2=A0=C2=A0=C2=A0 if (room) =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 return PAGE_SIZE - room; ... Thanks