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 E9188C77B70 for ; Mon, 17 Apr 2023 06:42:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230002AbjDQGmR (ORCPT ); Mon, 17 Apr 2023 02:42:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37902 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229458AbjDQGmK (ORCPT ); Mon, 17 Apr 2023 02:42:10 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 32977268F for ; Sun, 16 Apr 2023 23:41:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1681713673; 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: in-reply-to:in-reply-to:references:references; bh=OxKMHMF5ij1bxNLeFZRcL6SeBcLJINT9bFcDHFvcGBQ=; b=YuETFynOezCctj1CJlHYhFR+u8Gtev3GqeiR4y5+NBR8qP9E3DPA4HBtcAIyNzhvt4sDLc kVVfYzhcOUvBNMtBVOY2BcM6VhjQ7bc3f3xvBEmtceifg98HEa3AKCm6ygU2JY+y0VuO19 roQOQ21fzHzFbHc1bga78lJrY93CVNk= Received: from mail-qv1-f70.google.com (mail-qv1-f70.google.com [209.85.219.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-180-5cKN0QHTOHybpL5XsSO3YQ-1; Mon, 17 Apr 2023 02:41:12 -0400 X-MC-Unique: 5cKN0QHTOHybpL5XsSO3YQ-1 Received: by mail-qv1-f70.google.com with SMTP id b5-20020a0cbf45000000b005e7e2c57182so12378828qvj.22 for ; Sun, 16 Apr 2023 23:41:11 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1681713671; x=1684305671; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=OxKMHMF5ij1bxNLeFZRcL6SeBcLJINT9bFcDHFvcGBQ=; b=MOPBP0OBfQjh/QLTAEBvHwB2sljYJt0yjdN1wG052OeCfmqsv8CSFJzKG+R0G7deo7 S7AHj6FIH4nm2/+wZNsCfLWgPsphfz7FiQXgO6RzAuU24ymsB0lCDB96giA/NeLmdvlE 0k2meJbYlR3sQolZBNlbuI6UhzvixrX3kpIRtzj5xklo80vCJMkWks4oOFzjMhJ1zz3m k4quaAxJEz/kquwc0FEelmXOKy7wp4PmK3NIj70EZWaB4rbhdQLsMIcmTNTdv3AVrrhn 5Fw/y1j3xTo+7mdchkJQONxwXtzB6QRqKU99/H5wyeP0fH5wwr9GuRiblQvX7ORW/rck Fq0g== X-Gm-Message-State: AAQBX9fmGwcvQvk/EzBksspSRN78tgqJxgQPn6eoalPnnT92AlustywX UxG4oeQ6ZgM1JmbCqWRRBcdG8zQ38RJ7brq/5O7NC1bUDWBrhbco+WXDSyj8ICte1x/F2JkWGcf Cqc+UdsTJR1RZmYEJ X-Received: by 2002:a05:622a:144:b0:3e3:9036:8d7b with SMTP id v4-20020a05622a014400b003e390368d7bmr23144625qtw.24.1681713671547; Sun, 16 Apr 2023 23:41:11 -0700 (PDT) X-Google-Smtp-Source: AKy350awUisy2QmOytI/7wHAUSKfUVvRV0PC8LxBgH9zz1azFDxXLfpwgedyZCjCtr2bsDRdI6Gagw== X-Received: by 2002:a05:622a:144:b0:3e3:9036:8d7b with SMTP id v4-20020a05622a014400b003e390368d7bmr23144611qtw.24.1681713671291; Sun, 16 Apr 2023 23:41:11 -0700 (PDT) Received: from redhat.com ([185.199.103.251]) by smtp.gmail.com with ESMTPSA id bi8-20020a05620a318800b007456b51ee13sm1898249qkb.16.2023.04.16.23.41.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 16 Apr 2023 23:41:10 -0700 (PDT) Date: Mon, 17 Apr 2023 02:41:04 -0400 From: "Michael S. Tsirkin" To: Alvaro Karsz Cc: Jason Wang , "davem@davemloft.net" , "edumazet@google.com" , "kuba@kernel.org" , "pabeni@redhat.com" , "virtualization@lists.linux-foundation.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH net] virtio-net: reject small vring sizes Message-ID: <20230417023911-mutt-send-email-mst@kernel.org> References: <20230416074607.292616-1-alvaro.karsz@solid-run.com> <20230416164453-mutt-send-email-mst@kernel.org> <20230417021725-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Apr 17, 2023 at 06:38:43AM +0000, Alvaro Karsz wrote: > > Actually, I think that all you need to do is disable NETIF_F_SG, > > and things will work, no? > > I think that this is not so simple, if I understand correctly, by disabling NETIF_F_SG we will never receive a chained skbs to transmit, but we still have more functionality to address, for example: > * The TX timeouts. I don't get it. With a linear skb we can transmit it as long as there's space for 2 entries in the vq: header and data. What's the source of the timeouts? > * Guest GSO/big MTU (without VIRTIO_NET_F_MRG_RXBUF?), we can't chain page size buffers anymore. I think we can. mergeable_min_buf_len will just be large. > > Alvaro, can you try? > > It won't matter at the moment, we'll get TX timeout after the first tx packet, we need to address this part as well.