From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber de Oliveira Costa Subject: Re: [PATCH] Make ballooning work with maxmem > mem (i386 version) Date: Fri, 10 Nov 2006 13:33:57 -0200 Message-ID: <20061110153357.GD32562@redhat.com> References: <20061110132407.GC32562@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii 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: Keir Fraser Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On Fri, Nov 10, 2006 at 03:23:15PM +0000, Keir Fraser wrote: > On 10/11/06 13:24, "Glauber de Oliveira Costa" wrote: > > > Trying to start a guest with maxmem > mem and then balloon up to a value > > greater than mem is currently failing. This have been already discovered > > (patch sent some days ago) for x86_64. i386 suffers from the same > > problem. > > > > This patch fixes it. > > I took both patches and then changed my mind and immediately reverted them. > There is a better way: we should support the XENMEM_memory_map hypercall. > We should provide a hypercall (domctl) to set a memory_map_limit parameter > and then Xen can use that to fake a memory map when XENMEM_memory_map is > called. The tools can set that parameter from config['maxmem']. And what happens when the hypercall ever returns ENOSYS, like a kernel running in a bit old Hypervisor? IMHO,If we have to ever fallback into default assumptions, it seems wiser to extend the physicall map to maximum_reservation, not current_reservation. -- Glauber de Oliveira Costa Red Hat Inc. "Free as in Freedom"