From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: virtio scsi host draft specification, v3 Date: Wed, 29 Jun 2011 12:35:51 +0200 Message-ID: <4E0B0007.3050901@redhat.com> References: <4DEE2B15.4090809@redhat.com> <4DF21447.6090005@suse.de> <20110612075140.GB11941@redhat.com> <4E0AE0FE.2090905@redhat.com> <20110629100341.GC22900@infradead.org> <4E0AF925.2050707@redhat.com> <20110629103139.GC16757@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Christoph Hellwig , Hannes Reinecke , Linux Virtualization , Linux Kernel Mailing List , qemu-devel , Rusty Russell , Stefan Hajnoczi , Christoph Hellwig , "kvm@vger.kernel.org" To: "Michael S. Tsirkin" Return-path: In-Reply-To: <20110629103139.GC16757@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 06/29/2011 12:31 PM, Michael S. Tsirkin wrote: > On Wed, Jun 29, 2011 at 12:06:29PM +0200, Paolo Bonzini wrote: >> On 06/29/2011 12:03 PM, Christoph Hellwig wrote: >>>> I agree here, in fact I misread Hannes's comment as "if a driver >>>> uses more than one queue it is responsibility of the driver to >>>> ensure strict request ordering". If you send requests to different >>>> queues, you know that those requests are independent. I don't think >>>> anything else is feasible in the virtio framework. >>> >>> That doesn't really fit very well with the SAM model. If we want >>> to use multiple queues for a single LUN it has to be transparent to >>> the SCSI command stream. Then again I don't quite see the use for >>> that anyway. >> >> Agreed, I see a use for multiple queues (MSI-X), but not for >> multiple queues shared by a single LUN. > > Then let's make it explicit in the spec? What, forbid it or say ordering is not guaranteed? The latter is already explicit with the wording suggested in the thread. Paolo