From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754346AbaCEMeM (ORCPT ); Wed, 5 Mar 2014 07:34:12 -0500 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.232]:28428 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753850AbaCEMds (ORCPT ); Wed, 5 Mar 2014 07:33:48 -0500 Date: Wed, 5 Mar 2014 07:33:44 -0500 From: Steven Rostedt To: Peter Zijlstra Cc: mingo@kernel.org, hpa@zytor.com, paulus@samba.org, linux-kernel@vger.kernel.org, acme@ghostprotocols.net, seiji.aguchi@hds.com, jolsa@redhat.com, vincent.weaver@maine.edu, tglx@linutronix.de, hpa@linux.intel.com, linux-tip-commits@vger.kernel.org Subject: Re: [tip:x86/urgent] x86, trace: Fix CR2 corruption when tracing page faults Message-ID: <20140305073344.2f179931@gandalf.local.home> In-Reply-To: <20140305122535.GA9987@twins.programming.kicks-ass.net> References: <20140228160526.GD1133@krava.brq.redhat.com> <20140305111415.GU9987@twins.programming.kicks-ass.net> <20140305072022.6f69f699@gandalf.local.home> <20140305122535.GA9987@twins.programming.kicks-ass.net> X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.22; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-RR-Connecting-IP: 107.14.168.142:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 5 Mar 2014 13:25:35 +0100 Peter Zijlstra wrote: > On Wed, Mar 05, 2014 at 07:20:22AM -0500, Steven Rostedt wrote: > > On Wed, 5 Mar 2014 12:14:15 +0100 > > Peter Zijlstra wrote: > > > > Please no! I used tracing of the do_page_fault function all the time. > > It is very useful. > > Why do you trace do_page_fault and not the __do_page_fault() function? > do_page_fault() is a minimal wrapper which doesn't actually do all that > much? Then we better make sure that __do_page_fault() is never inlined. Otherwise, it wont be available to trace. I'm fine with adding "notrace" to do_page_fault() and to trace_do_page_fault() as long as we also include a "noinline" to __do_page_fault(). Would need a comment stating why that noinline is there though. -- Steve