Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932540Ab2EaPPu (ORCPT ); Thu, 31 May 2012 11:15:50 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:26560 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932483Ab2EaPPs (ORCPT ); Thu, 31 May 2012 11:15:48 -0400 X-Authority-Analysis: v=2.0 cv=cssZYiEi c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=XQbtiDEiEegA:10 a=oi6mPzrycosA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=meVymXHHAAAA:8 a=ayC55rCoAAAA:8 a=nwS0t3WeWGV9GlwFZ-AA:9 a=PUjeQqilurYA:10 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Message-ID: <1338477346.13348.351.camel@gandalf.stny.rr.com> Subject: Re: Re: [RFC PATCH -tip 0/9]ftrace, kprobes: Ftrace-based kprobe optimization From: Steven Rostedt To: Masami Hiramatsu Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Ananth N Mavinakayanahalli , "Frank Ch. Eigler" , Andrew Morton , Frederic Weisbecker , yrl.pp-manager.tt@hitachi.com Date: Thu, 31 May 2012 11:15:46 -0400 In-Reply-To: <4FC787D8.4010904@hitachi.com> References: <20120529124833.9191.23007.stgit@localhost.localdomain> <1338331514.13348.298.camel@gandalf.stny.rr.com> <4FC5C55E.9000909@hitachi.com> <1338377978.13348.308.camel@gandalf.stny.rr.com> <4FC787D8.4010904@hitachi.com> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.2.2-1 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1430 Lines: 38 On Fri, 2012-06-01 at 00:01 +0900, Masami Hiramatsu wrote: > OK, that's same as what I expected. In that case, > all __kprobes functions are already filtered out > by kprobes itself. So we don't need to set that anymore. > > Hmm, CFLAGS_REMOVE_kprobes.o can also keep kprobes from > function tracer. So I'd like to try to use that instead > of including notrace into __kprobes. > However, in that case, kprobe users must remove -pg from > their kernel modules too, and take care that they must > call only notrace kernel APIs... > > Perhaps, we'd better introduce new kprobe flag which allow > kprobe to accept new probe on ftrace, so that user can > explicitly understand what he will do. Please do not make kprobe functions not allow function tracing! I *want* to trace these functions! For example, I trace functions in NMIs all the time, and I know these are prohibited by kprobes. Why can't we function trace this? If kprobes does not trace functions marked with kprobes already, then it should not have any issue. Kprobes will only use the function tracer for what its allowed to use. Do not remove -pg from anything to satisfy kprobes. It shouldn't need it. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/