From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH] export notifier #1 Date: Wed, 23 Jan 2008 10:36:29 +1100 Message-ID: <1201044989.6807.46.camel@pasglop> References: <20080113162418.GE8736@v2.random> <20080116124256.44033d48@bree.surriel.com> <478E4356.7030303@qumranet.com> <20080117162302.GI7170@v2.random> <478F9C9C.7070500@qumranet.com> <20080117193252.GC24131@v2.random> <20080121125204.GJ6970@v2.random> <4795F9D2.1050503@qumranet.com> <20080122144332.GE7331@v2.random> <20080122200858.GB15848@v2.random> Reply-To: benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Andrew Morton , Nick Piggin , Andrea Arcangeli , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, steiner-sJ/iWh9BUns@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Avi Kivity , kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, daniel.blueman-xqY44rlHlBpWk0Htik3J/w@public.gmane.org, holt-sJ/iWh9BUns@public.gmane.org, Hugh Dickins 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 On Tue, 2008-01-22 at 12:34 -0800, Christoph Lameter wrote: > > - Notifiers are called *after* we tore down ptes. At that point pages > may already have been freed and reused. This means that there can > still be uses of the page by the user of mmu_ops after the OS has > dropped its mapping. IMHO the foreign entity needs to drop its > mappings first. That also ensures that the entities operated > upon continue to exist. That's definitely an issue. Maybe having the foreign entity get a reference to the page and drop it when it unmaps would help ? > - anon_vma/inode and pte locks are held during callbacks. So how does that fix the problem of sleeping then ? Ben. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/