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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 82DD6C43461 for ; Mon, 17 May 2021 20:23:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 589DD610A1 for ; Mon, 17 May 2021 20:23:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242364AbhEQUZP (ORCPT ); Mon, 17 May 2021 16:25:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36268 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241818AbhEQUZK (ORCPT ); Mon, 17 May 2021 16:25:10 -0400 Received: from mail-vs1-xe35.google.com (mail-vs1-xe35.google.com [IPv6:2607:f8b0:4864:20::e35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C43F9C061756 for ; Mon, 17 May 2021 13:23:52 -0700 (PDT) Received: by mail-vs1-xe35.google.com with SMTP id f15so2467671vsq.12 for ; Mon, 17 May 2021 13:23:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=TNVxp+4uYZU44gvo81BAyFu2mBsVyk6HxBgwuTdRjGw=; b=Xb7tt3YStfK16ujxVVCoZcExFZ22Uh+FtP8r3MT4LMYX1A5AgkQEaEGiKG5wJH+qdP PeNZ4c6i8DVxyi57luCsqW5Ang2kb43bKhIFOEcYFm/B8/pxVqavwixiTK5k8mW1PvXM f8ipUarjrgWCa6PhRPlYtawPv/yyGxu3TENCGJfGc6r6YdP326WIN+M1FxI5Ie18ylvj c5ONkEc6z+UwtEdeUnoVROVztdfeshg5E4q3VJu1YsYwfEc0Gsi8mBDqlrDwOfmwYbWO xZd4kPYJn8JPLDxoDJ6i7VJUIWRFHKeR00WgLYTTv5UT07AcWjY2IpnpdzAO254m4FmG epkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=TNVxp+4uYZU44gvo81BAyFu2mBsVyk6HxBgwuTdRjGw=; b=hd9rS++37LGpyoCUCavtSZUXGEZulRMVpcP2cpiGpfIkEDMpTW7vhqYPyf7MS9e1mY PiwDA6ZsdKuqG5DPyHyFEqgOerl4fedAZRKknN+LUsC+YBmtznn0ZPNWHy/Ah81PIJPA Xkd4xxI7psS8z4dklTdrjSUQtyiJ+osBUhH7zFJczN+17k14cfeud1ijwm6Wrhw6opWE id3jRE97TAyr/iBaUAKE9qh3YV6Q+hnRkigaXmRuM7td+gYO68jyEenIN3hw/5tE0TPG vEH/6VOe4i0Ob+2WpJA/Fy9hdCfo12UU4DEAgQhUxABNIL2zaA7kwoQYeod2VPxNEBMn rDSw== X-Gm-Message-State: AOAM532BNd1GeAjZQCPIHS/QtkwWQ99Rbah2B0uoiorDpqpKzySHwiX4 Behde3Cx09M89qd/7xZLmxGciG9l2r2aWPBu X-Google-Smtp-Source: ABdhPJy0wNcMTKIzs2VLyzUq/TqeyawQ8QlDbvH2c/w7PPfUPrP30nU9sGj3Hq3gfTv70gO4RhHg4A== X-Received: by 2002:a67:ce81:: with SMTP id c1mr2072204vse.28.1621283031663; Mon, 17 May 2021 13:23:51 -0700 (PDT) Received: from mail-vs1-f47.google.com (mail-vs1-f47.google.com. [209.85.217.47]) by smtp.gmail.com with ESMTPSA id m27sm1917686vsj.4.2021.05.17.13.23.49 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 17 May 2021 13:23:50 -0700 (PDT) Received: by mail-vs1-f47.google.com with SMTP id j13so3793374vsf.2 for ; Mon, 17 May 2021 13:23:49 -0700 (PDT) X-Received: by 2002:a67:fe57:: with SMTP id m23mr2025033vsr.47.1621283029295; Mon, 17 May 2021 13:23:49 -0700 (PDT) MIME-Version: 1.0 References: <56270996-33a6-d71b-d935-452dad121df7@linux.alibaba.com> In-Reply-To: From: Willem de Bruijn Date: Mon, 17 May 2021 16:23:10 -0400 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: virtio_net: BQL? To: Dave Taht Cc: Xianting Tian , "Michael S. Tsirkin" , Jason Wang , "David S. Miller" , Jakub Kicinski , virtualization , Linux Kernel Network Developers , LKML Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 17, 2021 at 2:44 PM Dave Taht wrote: > > Not really related to this patch, but is there some reason why virtio > has no support for BQL? There have been a few attempts to add it over the years. Most recently, https://lore.kernel.org/lkml/20181205225323.12555-2-mst@redh= at.com/ That thread has a long discussion. I think the key open issue remains "The tricky part is the mode switching between napi and no napi." > On Mon, May 17, 2021 at 11:41 AM Xianting Tian > wrote: > > > > BUG_ON() uses unlikely in if(), which can be optimized at compile time. > > > > Signed-off-by: Xianting Tian > > --- > > drivers/net/virtio_net.c | 5 ++--- > > 1 file changed, 2 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > index c921ebf3ae82..212d52204884 100644 > > --- a/drivers/net/virtio_net.c > > +++ b/drivers/net/virtio_net.c > > @@ -1646,10 +1646,9 @@ static int xmit_skb(struct send_queue *sq, struc= t > > sk_buff *skb) > > else > > hdr =3D skb_vnet_hdr(skb); > > > > - if (virtio_net_hdr_from_skb(skb, &hdr->hdr, > > + BUG_ON(virtio_net_hdr_from_skb(skb, &hdr->hdr, > > virtio_is_little_endian(vi->vdev), = false, > > - 0)) > > - BUG(); > > + 0)); > > > > if (vi->mergeable_rx_bufs) > > hdr->num_buffers =3D 0; > > -- > > 2.17.1 > > > > > -- > Latest Podcast: > https://www.linkedin.com/feed/update/urn:li:activity:6791014284936785920/ > > Dave T=C3=A4ht CTO, TekLibre, LLC 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=-10.5 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 7AF0DC43460 for ; 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[209.85.217.48]) by smtp.gmail.com with ESMTPSA id f65sm947358vke.43.2021.05.17.13.23.49 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 17 May 2021 13:23:50 -0700 (PDT) Received: by mail-vs1-f48.google.com with SMTP id f15so2467584vsq.12 for ; Mon, 17 May 2021 13:23:49 -0700 (PDT) X-Received: by 2002:a67:fe57:: with SMTP id m23mr2025033vsr.47.1621283029295; Mon, 17 May 2021 13:23:49 -0700 (PDT) MIME-Version: 1.0 References: <56270996-33a6-d71b-d935-452dad121df7@linux.alibaba.com> In-Reply-To: From: Willem de Bruijn Date: Mon, 17 May 2021 16:23:10 -0400 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: virtio_net: BQL? To: Dave Taht Cc: "Michael S. Tsirkin" , Xianting Tian , Linux Kernel Network Developers , LKML , virtualization , Jakub Kicinski , "David S. Miller" X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" T24gTW9uLCBNYXkgMTcsIDIwMjEgYXQgMjo0NCBQTSBEYXZlIFRhaHQgPGRhdmUudGFodEBnbWFp bC5jb20+IHdyb3RlOgo+Cj4gTm90IHJlYWxseSByZWxhdGVkIHRvIHRoaXMgcGF0Y2gsIGJ1dCBp cyB0aGVyZSBzb21lIHJlYXNvbiB3aHkgdmlydGlvCj4gaGFzIG5vIHN1cHBvcnQgZm9yIEJRTD8K ClRoZXJlIGhhdmUgYmVlbiBhIGZldyBhdHRlbXB0cyB0byBhZGQgaXQgb3ZlciB0aGUgeWVhcnMu CgpNb3N0IHJlY2VudGx5LCBodHRwczovL2xvcmUua2VybmVsLm9yZy9sa21sLzIwMTgxMjA1MjI1 MzIzLjEyNTU1LTItbXN0QHJlZGhhdC5jb20vCgpUaGF0IHRocmVhZCBoYXMgYSBsb25nIGRpc2N1 c3Npb24uIEkgdGhpbmsgdGhlIGtleSBvcGVuIGlzc3VlIHJlbWFpbnMKCiJUaGUgdHJpY2t5IHBh cnQgaXMgdGhlIG1vZGUgc3dpdGNoaW5nIGJldHdlZW4gbmFwaSBhbmQgbm8gbmFwaS4iCgo+IE9u IE1vbiwgTWF5IDE3LCAyMDIxIGF0IDExOjQxIEFNIFhpYW50aW5nIFRpYW4KPiA8eGlhbnRpbmcu dGlhbkBsaW51eC5hbGliYWJhLmNvbT4gd3JvdGU6Cj4gPgo+ID4gQlVHX09OKCkgdXNlcyB1bmxp a2VseSBpbiBpZigpLCB3aGljaCBjYW4gYmUgb3B0aW1pemVkIGF0IGNvbXBpbGUgdGltZS4KPiA+ Cj4gPiBTaWduZWQtb2ZmLWJ5OiBYaWFudGluZyBUaWFuIDx4aWFudGluZy50aWFuQGxpbnV4LmFs aWJhYmEuY29tPgo+ID4gLS0tCj4gPiAgIGRyaXZlcnMvbmV0L3ZpcnRpb19uZXQuYyB8IDUgKyst LS0KPiA+ICAgMSBmaWxlIGNoYW5nZWQsIDIgaW5zZXJ0aW9ucygrKSwgMyBkZWxldGlvbnMoLSkK PiA+Cj4gPiBkaWZmIC0tZ2l0IGEvZHJpdmVycy9uZXQvdmlydGlvX25ldC5jIGIvZHJpdmVycy9u ZXQvdmlydGlvX25ldC5jCj4gPiBpbmRleCBjOTIxZWJmM2FlODIuLjIxMmQ1MjIwNDg4NCAxMDA2 NDQKPiA+IC0tLSBhL2RyaXZlcnMvbmV0L3ZpcnRpb19uZXQuYwo+ID4gKysrIGIvZHJpdmVycy9u ZXQvdmlydGlvX25ldC5jCj4gPiBAQCAtMTY0NiwxMCArMTY0Niw5IEBAIHN0YXRpYyBpbnQgeG1p dF9za2Ioc3RydWN0IHNlbmRfcXVldWUgKnNxLCBzdHJ1Y3QKPiA+IHNrX2J1ZmYgKnNrYikKPiA+ ICAgICAgICAgZWxzZQo+ID4gICAgICAgICAgICAgICAgIGhkciA9IHNrYl92bmV0X2hkcihza2Ip Owo+ID4KPiA+IC0gICAgICAgaWYgKHZpcnRpb19uZXRfaGRyX2Zyb21fc2tiKHNrYiwgJmhkci0+ aGRyLAo+ID4gKyAgICAgICBCVUdfT04odmlydGlvX25ldF9oZHJfZnJvbV9za2Ioc2tiLCAmaGRy LT5oZHIsCj4gPiAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICB2aXJ0aW9faXNf bGl0dGxlX2VuZGlhbih2aS0+dmRldiksIGZhbHNlLAo+ID4gLSAgICAgICAgICAgICAgICAgICAg ICAgICAgICAgICAgICAgMCkpCj4gPiAtICAgICAgICAgICAgICAgQlVHKCk7Cj4gPiArICAgICAg ICAgICAgICAgICAgICAgICAgICAgICAgICAgICAwKSk7Cj4gPgo+ID4gICAgICAgICBpZiAodmkt Pm1lcmdlYWJsZV9yeF9idWZzKQo+ID4gICAgICAgICAgICAgICAgIGhkci0+bnVtX2J1ZmZlcnMg PSAwOwo+ID4gLS0KPiA+IDIuMTcuMQo+ID4KPgo+Cj4gLS0KPiBMYXRlc3QgUG9kY2FzdDoKPiBo dHRwczovL3d3dy5saW5rZWRpbi5jb20vZmVlZC91cGRhdGUvdXJuOmxpOmFjdGl2aXR5OjY3OTEw MTQyODQ5MzY3ODU5MjAvCj4KPiBEYXZlIFTDpGh0IENUTywgVGVrTGlicmUsIExMQwpfX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpWaXJ0dWFsaXphdGlvbiBt YWlsaW5nIGxpc3QKVmlydHVhbGl6YXRpb25AbGlzdHMubGludXgtZm91bmRhdGlvbi5vcmcKaHR0 cHM6Ly9saXN0cy5saW51eGZvdW5kYXRpb24ub3JnL21haWxtYW4vbGlzdGluZm8vdmlydHVhbGl6 YXRpb24=