From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753049AbaCMDVY (ORCPT ); Wed, 12 Mar 2014 23:21:24 -0400 Received: from mail.efficios.com ([78.47.125.74]:53476 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752834AbaCMDVX (ORCPT ); Wed, 12 Mar 2014 23:21:23 -0400 Date: Thu, 13 Mar 2014 03:21:27 +0000 (UTC) From: Mathieu Desnoyers To: Andi Kleen 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 Message-ID: <2020214533.2317.1394680887617.JavaMail.zimbra@efficios.com> In-Reply-To: <20140313031501.GW22728@two.firstfloor.org> References: <20140307150920.881849073@goodmis.org> <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> <20140313031501.GW22728@two.firstfloor.org> Subject: Re: [for-next][PATCH 08/20] tracing: Warn if a tracepoint is not set via debugfs MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [206.248.138.119] X-Mailer: Zimbra 8.0.5_GA_5839 (ZimbraWebClient - FF27 (Linux)/8.0.5_GA_5839) Thread-Topic: tracing: Warn if a tracepoint is not set via debugfs Thread-Index: qOrPFm37aqhYRkZEXSeyIy8U+DjR/Q== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- Original Message ----- > 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" > > Sent: Wednesday, March 12, 2014 11:15:01 PM > Subject: Re: [for-next][PATCH 08/20] tracing: Warn if a tracepoint is not set via debugfs > > 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. As I just replied to Steven, I now see that I mixed up concerns about static keys, and the prior kernel markers, with tracepoint concerns. The way they are implemented are very much different (Hey! I should know, I wrote that code some 6 years ago!) ;) > > > > > 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. OK, thanks for the explanations! Mathieu > > -Andi > -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com