From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tim Deegan Subject: Re: [RFC][PATCH] Basic support for page offline Date: Mon, 2 Mar 2009 11:56:07 +0000 Message-ID: <20090302115607.GA6322@york.uk.xensource.com> References: <20090213170341.GC17060@york.uk.xensource.com> <20090216143122.GD17060@york.uk.xensource.com> <20090218152020.GB28209@york.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Return-path: Content-Disposition: inline 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: "Jiang, Yunhong" Cc: "xen-devel@lists.xensource.com" , Keir Fraser List-Id: xen-devel@lists.xenproject.org At 14:37 +0000 on 19 Feb (1235054276), Jiang, Yunhong wrote: > > >> It should be possible to have the tools do all the PTE manipulations > >> with MMU update hypercalls (I think -- Keir may correct me here). Then > >> the final hypercall to surrender the page will fail if the grant tables > >> are wrong; if it does, put the PTEs back and fall back to a live > >> migration. Isn't that what your in-xen code does anyway? > > Tim, after checking the code more carefully, seems currently the MMU update hypercalls (including mod_lx_entry ) assume it is for current domain, while in our usage model, it will update MMU for other domain, so I will try to do following changes: 1) change mod_lx_entry() to get a domain parameter 2) Add a new hypercall (or a new command to do_mmu_update ) to update the MMU for other domain. I'm not sure if there are other usage model for such requirement, and if such changes acceptable? Any feedback is welcome. > Sorry for the delay -- I was travelling around the summit and this got lost. Yes, I think this is an OK approach. I doubt there will be many other users of such a hypercall since most OSes will get upset by their PTEs changing under their feet, but I prefer it to the current patch. Cheers, Tim. -- Tim Deegan Principal Software Engineer, Citrix Systems (R&D) Ltd. [Company #02300071, SL9 0DZ, UK.]