From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Durrant Subject: Re: Balloons, crash-dumps, populate-on-demand, and shared zero pages Date: Thu, 20 Aug 2009 11:56:05 +0100 Message-ID: <4A8D2BC5.5060408@citrix.com> References: <20090820103921.GA30044@weybridge.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090820103921.GA30044@weybridge.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Steven Smith Cc: George Dunlap , Gianluca Guida , "xen-devel@lists.xensource.com" , Keir Fraser List-Id: xen-devel@lists.xenproject.org Steven Smith wrote: > That would make things marginally easier on the drivers, but it's at > the expense of potentially more subtle errors when something goes > wrong. At the moment, if the balloon driver tries to deflate the > balloon too far, the populate hypercall fails and it's very obvious > what's gone wrong, whereas with an implicit re-populate it'll look > like everything's working fine for some time afterwards, until the > guest touches too many pages and PoD kills it. > If the balloon driver deflated too far, that would be a bug in the balloon driver, and if Windows doesn't scrub the memory when it's freed we could do that ourselves so at least PoD would kill the guest at the right juncture. Paul -- =============================== Paul Durrant, Software Engineer Citrix Systems (R&D) Ltd. First Floor, Building 101 Cambridge Science Park Milton Road Cambridge CB4 0FY United Kingdom ===============================