From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37295) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fihTZ-0008KC-0S for qemu-devel@nongnu.org; Thu, 26 Jul 2018 10:42:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fihTV-0006yI-Vv for qemu-devel@nongnu.org; Thu, 26 Jul 2018 10:42:44 -0400 Date: Thu, 26 Jul 2018 16:42:32 +0200 From: Kevin Wolf Message-ID: <20180726144232.GE4215@localhost.localdomain> References: <20180724200343.13733-1-lbloch@janustech.com> <20180724200343.13733-4-lbloch@janustech.com> <20180725082611.GA4879@localhost.localdomain> <32a32b18-0c7c-63cd-3b1d-429717b23a85@redhat.com> <499d5d12-cdba-76e4-3b2e-122675ef9eec@janustech.com> <20180725133243.GC4879@localhost.localdomain> <20180725155323.GD4879@localhost.localdomain> <0638cd7c-23f7-0f99-735b-c3fb3102e254@janustech.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0638cd7c-23f7-0f99-735b-c3fb3102e254@janustech.com> Subject: Re: [Qemu-devel] [PATCH v3 3/5] qcow2: Introduce an option for sufficient L2 cache for the entire image List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Leonid Bloch Cc: Eric Blake , qemu-devel@nongnu.org, qemu-block@nongnu.org, Max Reitz Am 26.07.2018 um 14:24 hat Leonid Bloch geschrieben: > > > You mean with QDict? I'll look into that now. But already sent v5 before > > > reading this email. > > > > Yes, with reading it from the QDict. (Or whatever the simplest way is > > that results in the right external interface, but I suppose this is the > > one.) > > Well, there is a problem with that: I can easily isolate > l2-cache-size from QDict, check if it is "full", and if it is - do whatever > is needed, and delete this option before parsing. But what if it is "foo"? > It will not get deleted, and the regular QEMU_OPT_SIZE parsing error will > appear, stating that l2-cache-size "expects a non-negative number..." - no > word about that it can expect "full" as well. Now, one can try to modify > local_err->msg for this particular option, but this will require substantial > additional logic. I think considering this, it would be easier to stick with > a dedicated option, l2-cache-full. > > Do you think there is a smarter way to parse the l2-cache-size option, so it > would accept both size and "full", while handling errors correctly? It seems > more elegant to have a single option, but the internal handling will be more > elegant and simpler with two mutually exclusive options. I think we can live with the suboptimal error message for a while. Once qcow2 is QAPIfied, it should become easy to improve it. Let's not choose a worse design (that stays forever) for a temporarily better error message. > By the way, the L2 cache resizes now on image resize. Will send the changes > in v6. Thanks for the suggestion! Sounds good! Kevin