From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 30 Jan 2008 14:29:18 -0600 From: Jack Steiner Subject: Re: [patch 2/6] mmu_notifier: Callbacks to invalidate address ranges 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-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Andrea Arcangeli , Robin Holt , Avi Kivity , Izik Eidus , Nick Piggin , kvm-devel@lists.sourceforge.net, Benjamin Herrenschmidt , Peter Zijlstra , linux-kernel@vger.kernel.org, linux-mm@kvack.org, daniel.blueman@quadrics.com, Hugh Dickins List-ID: 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org