From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752792AbYA3SVY (ORCPT ); Wed, 30 Jan 2008 13:21:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753724AbYA3SVL (ORCPT ); Wed, 30 Jan 2008 13:21:11 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:44602 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752720AbYA3SVK (ORCPT ); Wed, 30 Jan 2008 13:21:10 -0500 Date: Wed, 30 Jan 2008 10:20:47 -0800 From: Arjan van de Ven To: Pekka Paalanen Cc: mingo@redhat.com, linux-kernel@vger.kernel.org, "Jan Beulich" , pq@iki.fi Subject: Re: [PATCH] x86: Add a list for custom page fault handlers. Message-ID: <20080130102047.59aae047@laptopd505.fenrus.org> In-Reply-To: <20080127185238.4bcac54b@daedalus.pq.iki.fi> References: <20080127185238.4bcac54b@daedalus.pq.iki.fi> Organization: Intel X-Mailer: Claws Mail 3.2.0 (GTK+ 2.12.3; 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 Sun, 27 Jan 2008 18:52:38 +0200 Pekka Paalanen wrote: > From: Pekka Paalanen > > Provides kernel modules a way to register custom page fault handlers. > On every page fault, except those handled in vmalloc_fault(), this > will call a list of registered functions. The functions may handle > the fault and force do_page_fault() to return immediately. > > This functionality is similar to the now removed page fault notifiers. > Custom page fault handlers are used by debugging and reverse > engineering tools. Mmio-trace is one such tool and a patch to add it > into the tree will follow. > > The custom page fault handlers are called from the exact same points > in do_page_fault() as the page fault notifiers were. to be honest I don't like this approach. I fully would like to see mmio tracing in the kernel, but please make the hook explicit and direct (eg call the mmio tracing function, not some list) instead... -- 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