From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757858AbYAJAzx (ORCPT ); Wed, 9 Jan 2008 19:55:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754418AbYAJAzo (ORCPT ); Wed, 9 Jan 2008 19:55:44 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:40630 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753750AbYAJAzn (ORCPT ); Wed, 9 Jan 2008 19:55:43 -0500 Date: Wed, 9 Jan 2008 16:55:15 -0800 From: Arjan van de Ven To: Andi Kleen Cc: Christoph Hellwig , Benjamin Herrenschmidt , Pavel Roskin , Dave Airlie , Pekka Paalanen , linux-kernel@vger.kernel.org, jbeulich@novell.com Subject: Re: Replacement for page fault notifiers? Message-ID: <20080109165515.4a6256a8@laptopd505.fenrus.org> In-Reply-To: References: <20080108210638.5c9e093a@daedalus.pq.iki.fi> <20080108203235.GA772@infradead.org> <21d7e9970801081413n307ab07aq462a9fff014143ae@mail.gmail.com> <1199838407.6734.83.camel@pasglop> <1199902724.8050.11.camel@dv> <20080109182157.GA32754@infradead.org> <1199908703.6734.133.camel@pasglop> <20080109202254.GA5279@infradead.org> <20080109164241.7daa5770@laptopd505.fenrus.org> Organization: Intel X-Mailer: Claws Mail 3.0.2 (GTK+ 2.12.1; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 10 Jan 2008 01:47:16 +0100 Andi Kleen wrote: > Arjan van de Ven writes: > > > > I'm btw all in favor of making mmio tracing full fledged kernel > > infrastructure. This doesn't mean "notifier" imo; this means a real > > flag in the struct page, and then the page fault code can do > > > > if (page->flags & FLAG_MMIO_TRACED) > > mmio_trace(page, regs, whatever..); > > > > (probably surrounded by a CONFIG_ ifdef) > > THis is a TON lighter than a notifier chain, and actually what you > > want, you don't really want a notifier, you want a call back when a > > special kind of page is touched. > > That would assume that your mmio area has a struct page. In most PCs > the ones in the PCI hole don't > so you also call the function for all traps on pages without struct page; that should be extremely rare anyway, and the mmio_trace code can then look the page up. -- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org