From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Hering Subject: Re: [PATCH] [RFC] qemu-upstream: add discard support for xen_disk Date: Fri, 17 Jan 2014 16:38:20 +0100 Message-ID: <20140117153820.GA17569@aepfle.de> References: <1389304875-4311-1-git-send-email-olaf@aepfle.de> <20140117152930.GA13324@aepfle.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Stefano Stabellini Cc: xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On Fri, Jan 17, Stefano Stabellini wrote: > On Fri, 17 Jan 2014, Olaf Hering wrote: > > On Fri, Jan 17, Stefano Stabellini wrote: > > > > > On Thu, 9 Jan 2014, Olaf Hering wrote: > > > > The discard support is enabled unconditionally. But it would be worth to > > > > have a knob to disable it in case the backing file was intentionally > > > > created non-sparse to avoid fragmentation. > > > > How could this be knob be passed from domU.cfg:disk=[] to the actual > > > > qemu process? > > > > > > It would need to be on xenstore, because that is the only per-disk > > > interface xen_disk is listening to. > > > > I figured that out. There are already script=, backend= and other knobs. > > I will see how to add a discard=on|off to libxl and write that to the > > xenstore backend node so qemu can get it from there. > > What property name do you suggest? I have something like > > "toolstack-option-discard" in mind. > > discard_enabled? Isnt that name too generic? In the end that node is used also by backend and frontend. Olaf