Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935267AbaGYUQn (ORCPT ); Fri, 25 Jul 2014 16:16:43 -0400 Received: from mail-pd0-f180.google.com ([209.85.192.180]:57749 "EHLO mail-pd0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934542AbaGYUQl (ORCPT ); Fri, 25 Jul 2014 16:16:41 -0400 Date: Fri, 25 Jul 2014 13:16:39 -0700 From: Jesse Barnes To: Joerg Roedel Cc: Andrew Morton , Andrea Arcangeli , Peter Zijlstra , Rik van Riel , Hugh Dickins , Mel Gorman , Johannes Weiner , Jerome Glisse , jroedel@suse.de, Jay.Cornwall@amd.com, Oded.Gabbay@amd.com, John.Bridgman@amd.com, Suravee.Suthikulpanit@amd.com, ben.sander@amd.com, David Woodhouse , linux-kernel@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org Subject: Re: [PATCH 1/3] mmu_notifier: Add mmu_notifier_invalidate_range() Message-ID: <20140725131639.698f18ff@jbarnes-desktop> In-Reply-To: <1406212541-25975-2-git-send-email-joro@8bytes.org> References: <1406212541-25975-1-git-send-email-joro@8bytes.org> <1406212541-25975-2-git-send-email-joro@8bytes.org> X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 24 Jul 2014 16:35:39 +0200 Joerg Roedel wrote: > From: Joerg Roedel > > This notifier closes an important gap with the current > invalidate_range_start()/end() notifiers. The _start() part > is called when all pages are still mapped while the _end() > notifier is called when all pages are potentially unmapped > and already freed. > > This does not allow to manage external (non-CPU) hardware > TLBs with MMU-notifiers because there is no way to prevent > that hardware will establish new TLB entries between the > calls of these two functions. But this is a requirement to > the subsytem that implements these existing notifiers. > > To allow managing external TLBs the MMU-notifiers need to > catch the moment when pages are unmapped but not yet freed. > This new notifier catches that moment and notifies the > interested subsytem when pages that were unmapped are about > to be freed. The new notifier will only be called between > invalidate_range_start()/end(). So if we were actually sharing page tables, we should be able to make start/end no-ops and just use this new callback, assuming we didn't need to do any other serialization or debug stuff, right? Seems like a good addition, and saves us a bunch of trouble... Thanks, -- Jesse Barnes, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/