From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751570Ab0DSES5 (ORCPT ); Mon, 19 Apr 2010 00:18:57 -0400 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:49994 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751209Ab0DSES4 (ORCPT ); Mon, 19 Apr 2010 00:18:56 -0400 Date: Sun, 18 Apr 2010 21:19:00 -0700 (PDT) Message-Id: <20100418.211900.183039797.davem@davemloft.net> To: fweisbec@gmail.com Cc: rostedt@goodmis.org, linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, lizf@cn.fujitsu.com, laijs@cn.fujitsu.com Subject: Re: [PATCH] tracing: Dump either the oops's cpu source or all cpus buffers From: David Miller In-Reply-To: <1271623810-23700-1-git-send-regression-fweisbec@gmail.com> References: <1271623810-23700-1-git-send-regression-fweisbec@gmail.com> X-Mailer: Mew version 6.3 on Emacs 23.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Frederic Weisbecker Date: Sun, 18 Apr 2010 22:50:10 +0200 > The ftrace_dump_on_oops kernel parameter, sysctl and sysrq let one > dump every cpu buffers when an oops or panic happens. > > It's nice when you have few cpus but it may take ages if have many, > plus you miss the real origin of the problem in all the cpu traces. > > Sometimes, all you need is to dump the cpu buffer that triggered the > opps, most of the time it is our main interest. > > This patch modifies ftrace_dump_on_oops to handle this choice. > > The ftrace_dump_on_oops kernel parameter, when it comes alone, has > the same behaviour than before. But ftrace_dump_on_oops=orig_cpu > will only dump the buffer of the cpu that oops'ed. > > Similarly, sysctl kernel.ftrace_dump_on_oops=1 and > echo 1 > /proc/sys/kernel/ftrace_dump_on_oops keep their previous > behaviour. But setting 2 jumps into cpu origin dump mode. > > Signed-off-by: Frederic Weisbecker Thanks I was trying to figure out a way to make ftrace dump do exactly this over the past few days :-) Acked-by: David S. Miller