From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757793AbZCMCnx (ORCPT ); Thu, 12 Mar 2009 22:43:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758560AbZCMCik (ORCPT ); Thu, 12 Mar 2009 22:38:40 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.124]:56604 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758543AbZCMCia (ORCPT ); Thu, 12 Mar 2009 22:38:30 -0400 Message-Id: <20090313023827.173173817@goodmis.org> References: <20090313023704.971438367@goodmis.org> User-Agent: quilt/0.46-1 Date: Thu, 12 Mar 2009 22:37:15 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Peter Zijlstra , Frederic Weisbecker , Lai Jiangshan , KOSAKI Motohiro , Steven Rostedt Subject: [PATCH 11/16] tracing: explain why stack tracer is empty Content-Disposition: inline; filename=0011-tracing-explain-why-stack-tracer-is-empty.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Rostedt If the stack tracing is disabled (by default) the stack_trace file will only contain the header: # cat /debug/tracing/stack_trace Depth Size Location (0 entries) ----- ---- -------- This can be frustrating to a developer that does not realize that the stack tracer is disabled. This patch adds the following text: # cat /debug/tracing/stack_trace Depth Size Location (0 entries) ----- ---- -------- # # Stack tracer disabled # # To enable the stack tracer, either add 'stacktrace' to the # kernel command line # or 'echo 1 > /proc/sys/kernel/stack_tracer_enabled' # Signed-off-by: Steven Rostedt --- kernel/trace/trace_stack.c | 15 +++++++++++++++ 1 files changed, 15 insertions(+), 0 deletions(-) diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 4564fd9..91ccbf3 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -245,6 +245,17 @@ static int trace_lookup_stack(struct seq_file *m, long i) #endif } +static void print_disabled(struct seq_file *m) +{ + seq_puts(m, "#\n" + "# Stack tracer disabled\n" + "#\n" + "# To enable the stack tracer, either add 'stacktrace' to the\n" + "# kernel command line\n" + "# or 'echo 1 > /proc/sys/kernel/stack_tracer_enabled'\n" + "#\n"); +} + static int t_show(struct seq_file *m, void *v) { long i; @@ -255,6 +266,10 @@ static int t_show(struct seq_file *m, void *v) " (%d entries)\n" " ----- ---- --------\n", max_stack_trace.nr_entries); + + if (!stack_tracer_enabled && !max_stack_size) + print_disabled(m); + return 0; } -- 1.6.1.3 --