From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59278) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eLtyC-00041g-HN for qemu-devel@nongnu.org; Mon, 04 Dec 2017 11:51:53 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eLty7-00047p-MH for qemu-devel@nongnu.org; Mon, 04 Dec 2017 11:51:52 -0500 Date: Mon, 4 Dec 2017 17:51:42 +0100 From: Cornelia Huck Message-ID: <20171204175142.7af81901.cohuck@redhat.com> In-Reply-To: References: <20171128134648.21530-1-cohuck@redhat.com> <6513d1c5-032e-b9d0-3dab-f2d0bd337ae2@linux.vnet.ibm.com> <20171128152718.229a20fe.cohuck@redhat.com> <389e2efe-cbc5-8a78-e009-cd330d4ede6a@linux.vnet.ibm.com> <20171204102220.31fce015.cohuck@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH RFC 0/2] s390x: cut down on unattached devices List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Halil Pasic Cc: qemu-devel@nongnu.org, qemu-s390x@nongnu.org, borntraeger@de.ibm.com, pmorel@linux.vnet.ibm.com On Mon, 4 Dec 2017 15:47:37 +0100 Halil Pasic wrote: > On 12/04/2017 10:22 AM, Cornelia Huck wrote: > > On Fri, 1 Dec 2017 15:41:21 +0100 > > Halil Pasic wrote: > > > >> On 11/28/2017 04:21 PM, Halil Pasic wrote: > >> [..] > >>>>> Otherwise at first glance both patches seem sane. > >>>> > >>>> Can I count this as an ack, or do you plan to do more review? > >>>> > >>> > >>> Yes I was planning to give it another look. And I do already > >>> have questions. Isn't the QOM composition tree API? I mean > >>> let's assume the QMP commands working on this tree are not completely > >>> useless. How is client code (management software) supposed to work, > >>> assumed it can rely on paths of e.g. properties being stable. Just > >>> imagine we had this default-cssid property (for the sake of the > >>> argument, not like we want it) on the css bridge. > >> > >> Ping! I would like to get this clarified before proceeding with reviewing > >> this series. > > > > [It might be helpful to not drop cc:s.] > > > > Sorry. Wrong button. > > > I don't think we really want a static tree. As long as the devices are > > locateable, it should be fine. > > > > What do you mean by locateable in particular? > > Let's say I'm management software guy who want's to access a certain > property of a certain device. For that I'm supposed to use qom-get. Now > qom-get takes a path as input argument (absolute or relative). The question > is, how I'm supposed to figure out this path as management software developer? > In other words what is the algorithm? I'd expect qom-tree to put out a path to the right object. No idea if/how much management software relies on this. But hardcoded paths sound fragile to me. > > One naive approach would be, to assume that the path is stable between > releases. So I have to figure it out when I'm implementing the stuff, > and then it keeps working ever after. I read your answer as this naive > approach is wrong. > > (BTW I find static also confusing in this context.) > > [..] >