From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752550AbXCZNJ7 (ORCPT ); Mon, 26 Mar 2007 09:09:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752568AbXCZNJ7 (ORCPT ); Mon, 26 Mar 2007 09:09:59 -0400 Received: from verein.lst.de ([213.95.11.210]:37994 "EHLO mail.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752550AbXCZNJ6 (ORCPT ); Mon, 26 Mar 2007 09:09:58 -0400 Date: Mon, 26 Mar 2007 08:55:24 +0200 From: Christoph Hellwig To: Paul Mackerras Cc: Christoph Hellwig , akpm@osdl.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] move die notifier handling to common code Message-ID: <20070326065524.GA1163@lst.de> References: <20070319160218.GA27462@lst.de> <17927.8857.752570.69739@cargo.ozlabs.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <17927.8857.752570.69739@cargo.ozlabs.ibm.com> User-Agent: Mutt/1.3.28i X-Spam-Score: 1.363 (*) DATE_IN_PAST_06_12 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 26, 2007 at 11:32:09AM +1000, Paul Mackerras wrote: > Seems OK, although I think kprobes should not be using notify_die. > The set of events that kprobes is interested in has no intersection at > all with the set that any other consumer of the notify_die events is > interested in, on any architecture. > > Furthermore, the multiplexing of the kprobes events through notify_die > really serves no useful purpose. It just means that > kprobe_exceptions_notify has to demultiplex the events with a switch > statement. There is no significant common code for all events in > kprobe_exceptions_notify, just a simple check whether the event > happened in user mode. > > However, all that is in arch code so can be changed per-arch if > desired. I tend to agree. Unfortunately powers higher than me like these horrible notifier schemes. Then again at least the die path is not performance critical unlike the page faul path where I still need a comment for you on getting rid of the notifier.