From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753166AbaCMDPF (ORCPT ); Wed, 12 Mar 2014 23:15:05 -0400 Received: from one.firstfloor.org ([193.170.194.197]:56770 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753123AbaCMDPD (ORCPT ); Wed, 12 Mar 2014 23:15:03 -0400 Date: Thu, 13 Mar 2014 04:15:01 +0100 From: Andi Kleen To: Mathieu Desnoyers Cc: Andi Kleen , Steven Rostedt , "Frank Ch. Eigler" , linux-kernel@vger.kernel.org, Ingo Molnar , Frederic Weisbecker , Andrew Morton , Johannes Berg , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Greg Kroah-Hartman , lttng-dev , Rusty Russell Subject: Re: [for-next][PATCH 08/20] tracing: Warn if a tracepoint is not set via debugfs Message-ID: <20140313031501.GW22728@two.firstfloor.org> References: <20140307150920.881849073@goodmis.org> <20140312121813.1e0102aa@gandalf.local.home> <285520930.1511.1394642395537.JavaMail.zimbra@efficios.com> <20140312135059.2d497b58@gandalf.local.home> <1906756968.1732.1394650035535.JavaMail.zimbra@efficios.com> <20140312145802.4819511e@gandalf.local.home> <1177120325.1928.1394653861180.JavaMail.zimbra@efficios.com> <20140312203515.GV22728@two.firstfloor.org> <1083852821.1959.1394657227042.JavaMail.zimbra@efficios.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1083852821.1959.1394657227042.JavaMail.zimbra@efficios.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 12, 2014 at 08:47:07PM +0000, Mathieu Desnoyers wrote: > ----- Original Message ----- > > From: "Andi Kleen" > > To: "Mathieu Desnoyers" > > Cc: "Steven Rostedt" , "Frank Ch. Eigler" , linux-kernel@vger.kernel.org, "Ingo > > Molnar" , "Frederic Weisbecker" , "Andrew Morton" , > > "Johannes Berg" , "Linus Torvalds" , "Peter Zijlstra" > > , "Thomas Gleixner" , "Greg Kroah-Hartman" , > > "lttng-dev" , "Rusty Russell" , "Andi Kleen" > > Sent: Wednesday, March 12, 2014 4:35:15 PM > > Subject: Re: [for-next][PATCH 08/20] tracing: Warn if a tracepoint is not set via debugfs > > > > > So I understand that you wish to banish tracepoints from static inline > > > functions within headers to ensure they only appear within a single module. > > > This seems to be a step backward, but let's assume we stick to that rule. > > > Then how do you envision dealing with Link-Time Optimisations (LTO) ? > > > > I assume it uses the file name defines set by Kbuild? > > Just to make sure I understand your question: I understand that you are asking > whether tracepoints use file name defines at all in the naming of a tracepoint. > The answer to this question is: No, they do not. Ok. It uses kallsyms? That can change of course. > > > These don't change with > > LTO. It's whatever was specified at compile time. Also LTO doesn't > > inline over module boundaries (if the module is not built in) > > Good to know. Can it inline core kernel functions into a module ? Each module and the main kernel are currently LTO'ed separately. In theory it would be possible to change this, but likely at some compile time cost. -Andi