From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] vhost-net: switch to smp barriers Date: Sun, 07 Feb 2010 11:56:14 +0200 Message-ID: <4B6E8E3E.30705@redhat.com> References: <20100201172101.GA10900@redhat.com> <4B6E8B05.8070607@redhat.com> <20100207094441.GA20271@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20100207094441.GA20271@redhat.com> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: virtualization@lists.linuxfoundation.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