From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [ANNOUNCE] kvm-46 release Date: Wed, 10 Oct 2007 11:07:44 +0200 Message-ID: <470C9660.8090700@qumranet.com> References: <470C8D28.2060408@qumranet.com> <470C9034.2000206@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel To: Jun Koi Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Jun Koi wrote: > On 10/10/07, Avi Kivity wrote: > >> Jun Koi wrote: >> >>> Hi, >>> >>> On 10/10/07, Avi Kivity wrote: >>> >>> >>>> We've now switched to allocating guest memory in userspace rather than >>>> in the kernel. This is important if you have a mainframe, but also if >>>> you want to share memory between guests and implement nice features like >>>> swapping. >>>> >>>> >>> This is interesting! But how can we do that now? (share memory between guests) >>> >>> >>> >> It's not exposed by qemu, but you can now mmap() some file (or use SysV >> shared memory) and use that as guest memory. >> >> > > OK, lets say we have 2 guest VMs share a memory, like mmap() a tmpfs > file (which is actually in memory). Now one writes to the memory > (shared file). Can we guarantee that the memory immediately updated, > so other will see the change immediately? Or the data might be cached > for a while, befere being flushed to the shared memory? > Changes are visible immediately. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/