Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753199Ab2E3Ljm (ORCPT ); Wed, 30 May 2012 07:39:42 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:30859 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753160Ab2E3Ljk (ORCPT ); Wed, 30 May 2012 07:39:40 -0400 X-Authority-Analysis: v=2.0 cv=D8PF24tj c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=XQbtiDEiEegA:10 a=wwwCnHkgN0EA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=meVymXHHAAAA:8 a=ayC55rCoAAAA:8 a=muDU9TWqX4S6gBgt5GwA:9 a=PUjeQqilurYA:10 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Message-ID: <1338377978.13348.308.camel@gandalf.stny.rr.com> Subject: 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: Wed, 30 May 2012 07:39:38 -0400 In-Reply-To: <4FC5C55E.9000909@hitachi.com> References: <20120529124833.9191.23007.stgit@localhost.localdomain> <1338331514.13348.298.camel@gandalf.stny.rr.com> <4FC5C55E.9000909@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: 1157 Lines: 33 On Wed, 2012-05-30 at 15:59 +0900, Masami Hiramatsu wrote: > Hmm, I'm not so sure how the notrace and filter works. > What happens if I set a foo function-entry on filter > and keep notrace empty? > - only foo's nop is replaced with call? > - or all functions including foo is traced? >From Documentation/trace/ftrace.txt: "If a function exists in both set_ftrace_filter and set_ftrace_notrace, the function will _not_ be traced." The filters work exactly the same. If notrace always take precedence over filter. If you have foo and bar in filter, and put foo in notrace, then only bar is traced. "filter" means "limit tracing only to these functions" "notrace" means "do not trace this function" Think of 'filter' as a way of making the 'available_filter_functions' smaller. It filters the list. But 'notrace' is just like adding a 'notrace' tag. It stops it from being traced regardless. -- 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/