From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932098Ab0BGJ46 (ORCPT ); Sun, 7 Feb 2010 04:56:58 -0500 Received: from mx1.redhat.com ([209.132.183.28]:13109 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751260Ab0BGJ45 (ORCPT ); Sun, 7 Feb 2010 04:56:57 -0500 Message-ID: <4B6E8E3E.30705@redhat.com> Date: Sun, 07 Feb 2010 11:56:14 +0200 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.7) Gecko/20100120 Fedora/3.0.1-1.fc12 Thunderbird/3.0.1 MIME-Version: 1.0 To: "Michael S. Tsirkin" CC: Rusty Russell , kvm@vger.kernel.org, virtualization@lists.osdl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, David Miller Subject: Re: [PATCH] vhost-net: switch to smp barriers References: <20100201172101.GA10900@redhat.com> <4B6E8B05.8070607@redhat.com> <20100207094441.GA20271@redhat.com> In-Reply-To: <20100207094441.GA20271@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/07/2010 11:44 AM, Michael S. Tsirkin wrote: > On Sun, Feb 07, 2010 at 11:42:29AM +0200, Avi Kivity wrote: > >> On 02/01/2010 07:21 PM, Michael S. Tsirkin wrote: >> >>> vhost-net only uses memory barriers to control SMP effects >>> (communication with userspace potentially running on a different CPU), >>> so it should use SMP barriers and not mandatory barriers for memory >>> access ordering, as suggested by Documentation/memory-barriers.txt >>> >>> >>> >> A UP guest running on an SMP host still needs those barriers. >> > Correct. And since vhost net is running host-side, smp_XX > barriers will do exactly the right thing, right? > Right, of course. Mixed up virtio and vhost. -- error compiling committee.c: too many arguments to function