From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Durrant Subject: Re: Re: [PATCH] EPT: Only sync pcpus on which a domain's vcpus might be running Date: Fri, 18 Sep 2009 17:51:38 +0100 Message-ID: <4AB3BA9A.6080004@citrix.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: George Dunlap Cc: Xiaohui Xin , "xen-devel@lists.xensource.com" , Tim Deegan , Xin Li , Keir Fraser , Jun Nakajima List-Id: xen-devel@lists.xenproject.org George Dunlap wrote: > > In theory, the memory handed back by the balloon driver shouldn't be > touched by the OS. I think it would be OK if guess accesses to that > gfn space didn't fail for the guest giving up the pages; however, we > can't give the memory to another guest until we know for sure that the > first guest can't possibly access it anymore. I think we should be > able to modify the balloon driver to "batch" some number of updates; > say, 1024 at a time. Paul, any thoughts on this? > The decrease_reservation op is called with however many PFNs can fit into the Windows MDL structure (8184 for a 32-bit VM) so we already do things in pretty big batches. Paul -- =============================== Paul Durrant, Software Engineer Citrix Systems (R&D) Ltd. First Floor, Building 101 Cambridge Science Park Milton Road Cambridge CB4 0FY United Kingdom TEL: x35957 (+44 1223 225957) ===============================