From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Holt Subject: Re: [patch 2/3] mmu_notifier: Callbacks to invalidate address ranges Date: Fri, 1 Feb 2008 04:32:21 -0600 Message-ID: <20080201103221.GH26420@sgi.com> References: <20080131045750.855008281@sgi.com> <20080131045812.785269387@sgi.com> <20080201042408.GG26420@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Andrea Arcangeli , Peter Zijlstra , 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, Robin Holt To: Christoph Lameter Return-path: Content-Disposition: inline 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 Thu, Jan 31, 2008 at 08:43:58PM -0800, Christoph Lameter wrote: > On Thu, 31 Jan 2008, Robin Holt wrote: > > > > Index: linux-2.6/mm/memory.c > > ... > > > @@ -1668,6 +1678,7 @@ gotten: > > > page_cache_release(old_page); > > > unlock: > > > pte_unmap_unlock(page_table, ptl); > > > + mmu_notifier(invalidate_range_end, mm, 0); > > > > I think we can get an _end call without the _begin call before it. > > If that would be true then also the pte would have been left locked. > > We always hit unlock. Maybe I just do not see it? Maybe I haven't looked closely enough, but let's start with some common assumptions. Looking at do_wp_page from 2.6.24 (I believe that is what my work area is based upon). On line 1559, the function begins being declared. On lines 1614 and 1630, we do "goto unlock" where the _end callout is soon made. The _begin callout does not come until after those branches have been taken (occurs on line 1648). Thanks, Robin ------------------------------------------------------------------------- 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/