From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 31 Jan 2008 18:41:57 -0800 (PST) From: Christoph Lameter Subject: Re: mmu_notifier: invalidate_range for move_page_tables In-Reply-To: <20080201023815.GC26420@sgi.com> Message-ID: References: <20080131045750.855008281@sgi.com> <20080131045812.785269387@sgi.com> <20080131123118.GK7185@v2.random> <20080201001355.GU7185@v2.random> <20080201023815.GC26420@sgi.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Robin Holt Cc: Andrea Arcangeli , Avi Kivity , Izik Eidus , kvm-devel@lists.sourceforge.net, Peter Zijlstra , steiner@sgi.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, daniel.blueman@quadrics.com List-ID: On Thu, 31 Jan 2008, Robin Holt wrote: > On Thu, Jan 31, 2008 at 05:57:25PM -0800, Christoph Lameter wrote: > > Move page tables also needs to invalidate the external references > > and hold new references off while moving page table entries. > > I must admit to not having spent any time thinking about this, but aren't > we moving the entries from one set of page tables to the other, leaving > the pte_t entries unchanged. I guess I should go look, but could you > provide a quick pointer in the proper direction as to why we need to > recall externals when the before and after look of these page tables > will have the same information for the TLBs. remap changes the address of pages in a process. The pages appear at another address. Thus the external pte will have the wrong information if not invalidated. Do a man mremap -- 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