From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: mmu notifiers Date: Thu, 10 Jan 2008 13:44:18 +0200 Message-ID: <47860512.3040607@qumranet.com> References: <20080109181908.GS6958@v2.random> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Daniel J Blueman , Andrea Arcangeli To: Christoph Lameter 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 Christoph Lameter wrote: > On Wed, 9 Jan 2008, Andrea Arcangeli wrote: > > >> This patch is a first basic implementation of the mmu notifiers. More >> methods can be added in the future. >> >> In short when the linux VM decides to free a page, it will unmap it >> from the linux pagetables. However when a page is mapped not just by >> the regular linux ptes, but also from the shadow pagetables, it's >> currently unfreeable by the linux VM. >> > > Such a patch would also address issues that SGI has with exporting > mappings via XPMEM. Plus a variety of other uses. Go ahead and lets do > more in this area. > > Are the KVM folks interested in exporting memory from one guest to > another? That may also become possible with some of the work that we have > in progress and that also requires a patch like this. > > Actually sharing memory is possible even without this patch; one simply mmap()s a file into the address space of both guests. Or are you referring to something else? The patch does enable some nifty things; one example you may be familiar with is using page migration to move a guest from one numa node to another. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace