From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jack Steiner Subject: Re: [patch 2/6] mmu_notifier: Callbacks to invalidate address ranges Date: Wed, 30 Jan 2008 14:29:18 -0600 Message-ID: <20080130202918.GB11324@sgi.com> References: <20080129211759.GV7233@v2.random> <20080129220212.GX7233@v2.random> <20080130000039.GA7233@v2.random> <20080130002804.GA13840@sgi.com> <20080130133720.GM7233@v2.random> <20080130144305.GA25193@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Nick Piggin , Andrea Arcangeli , Peter Zijlstra , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Benjamin Herrenschmidt , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Avi Kivity , kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, daniel.blueman-xqY44rlHlBpWk0Htik3J/w@public.gmane.org, Robin Holt , Hugh Dickins 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 Wed, Jan 30, 2008 at 11:41:29AM -0800, Christoph Lameter wrote: > On Wed, 30 Jan 2008, Jack Steiner wrote: > > > I see what you mean. I need to review to mail to see why this changed > > but in the original discussions with Christoph, the invalidate_range > > callouts were suppose to be made BEFORE the pages were put on the freelist. > > Seems that we cannot rely on the invalidate_ranges for correctness at all? > We need to have invalidate_page() always. invalidate_range() is only an > optimization. > I don't understand your point "an optimization". How would invalidate_range as currently defined be correctly used? It _looks_ like it would work only if xpmem/gru/etc takes a refcnt on the page & drops it when invalidate_range is called. That may work (not sure) for xpmem but not for the GRU. --- jack ------------------------------------------------------------------------- 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/