From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759727Ab2CWTgm (ORCPT ); Fri, 23 Mar 2012 15:36:42 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:8523 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755746Ab2CWTgl (ORCPT ); Fri, 23 Mar 2012 15:36:41 -0400 X-Authority-Analysis: v=2.0 cv=NYRkJh/4 c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=XQbtiDEiEegA:10 a=wBLf1-ka6lYA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=pGLkceISAAAA:8 a=jQoND8bKIZ5rnDiqy54A:9 a=NkYwO1ZN8uvHiay6MRIA:7 a=PUjeQqilurYA:10 a=MSl-tDqOz04A:10 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Message-ID: <1332531400.23924.71.camel@gandalf.stny.rr.com> Subject: Re: [PATCH 1/1] ftrace: fix dynamic ftrace filter reset issue From: Steven Rostedt To: Rajesh Bhagat Cc: Frederic Weisbecker , Ingo Molnar , linux-kernel@vger.kernel.org Date: Fri, 23 Mar 2012 15:36:40 -0400 In-Reply-To: References: 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 On Wed, 2012-03-21 at 11:22 +0530, Rajesh Bhagat wrote: > >From 60ec8a88ba671fa0b424f7b4467dba3ea8a2a2c8 Mon Sep 17 00:00:00 2001 > From: Rajesh Bhagat > Date: Tue, 20 Mar 2012 10:35:59 +0530 > Subject: [PATCH 1/1] ftrace: fix dynamic ftrace filter reset issue > > This patch resets the trace_array using tracing_reset_online_cpus, if same > tracer is set again instead of just returning from funtion tracing_set_tracer. > > problem description > ------------------- > once function tracer is set, set_ftrace_filter not working. > /debug/tracing # echo function > current_tracer > /debug/tracing # echo schedule > set_ftrace_filter > /debug/tracing # echo function > current_tracer Sorry no. The correct way you want to do this is: /debug/tracing # echo > trace That will reset the buffer for you and give you the desired result. -- Steve > /debug/tracing # cat trace > # tracer: function > # > # TASK-PID CPU# TIMESTAMP FUNCTION > # | | | | | > -0 [000] 21.997778: irq_enter <-handle_IRQ > -0 [000] 21.997785: idle_cpu <-irq_enter > -0 [000] 21.997794: local_bh_disable <-irq_enter > -0 [000] 21.997800: tick_check_idle <-irq_enter > -0 [000] 21.997807: > tick_check_oneshot_broadcast <-tick_check_idle > -0 [000] 21.997814: _local_bh_enable <-irq_enter > > After applying this patch, only filtered functions are traced. > > Signed-off-by: Rajesh Bhagat > --- > kernel/trace/trace.c | 4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index a3f1bc5..f4fb190 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -3058,8 +3058,10 @@ static int tracing_set_tracer(const char *buf) > ret = -EINVAL; > goto out; > } > - if (t == current_trace) > + if (t == current_trace) { > + tracing_reset_online_cpus(tr); > goto out; > + } > > trace_branch_disable(); > if (current_trace && current_trace->reset)