From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <ian.campbell@citrix.com>
Subject: Re: Shared image files and block script performance
Date: Tue, 29 Sep 2015 10:25:32 +0100
Message-ID: <1443518732.16718.16.camel@citrix.com>
References: <7906712.vmDJM0hI90@mlatimer1.dnsdhcp.provo.novell.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
In-Reply-To: <7906712.vmDJM0hI90@mlatimer1.dnsdhcp.provo.novell.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Mike Latimer <mlatimer@suse.com>, xen-devel@lists.xen.org
List-Id: xen-devel@lists.xenproject.org

On Mon, 2015-09-28 at 17:14 -0600, Mike Latimer wrote:
> Any better options or ideas?

Is part of the problem that shell is a terrible choice for this kind of
check?

Would shelling out to a helper utility allow this to be written in
something better?

I think we'd still be constrained in the languages used, probably it would
have to be C to avoid adding dependencies on additional runtimes or
compilers, but that might be good enough to allow us to minimise the number
of times we need to go through the database. If nothing else it would make
it possible to use actual datastructures, locking, XS transactions etc.

Ian.