From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754269Ab3HaTVq (ORCPT ); Sat, 31 Aug 2013 15:21:46 -0400 Received: from e31.co.us.ibm.com ([32.97.110.149]:60598 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753000Ab3HaTVp (ORCPT ); Sat, 31 Aug 2013 15:21:45 -0400 Date: Sat, 31 Aug 2013 12:21:01 -0700 From: "Paul E. McKenney" To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Peter Zijlstra , Frederic Weisbecker , Jiri Olsa Subject: Re: [RFC][PATCH 08/18 v2] ftrace/rcu: Do not trace debug_lockdep_rcu_enabled() Message-ID: <20130831192101.GG3871@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20130831051117.884125230@goodmis.org> <20130831051701.767976027@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130831051701.767976027@goodmis.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13083119-8236-0000-0000-0000014F3DED Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Aug 31, 2013 at 01:11:25AM -0400, Steven Rostedt wrote: > From: "Steven Rostedt (Red Hat)" > > The function debug_lockdep_rcu_enabled() is part of the RCU lockdep > debugging, and is called very frequently. I found that if I enable > a lot of debugging and run the function graph tracer, this > function can cause a live lock of the system. > > We don't usually trace lockdep infrastructure, no need to trace > this either. > > Cc: Paul E. McKenney > Signed-off-by: Steven Rostedt Reviewed-by: Paul E. McKenney Or I can just take it, if you would rather. (If so, 3.12 or 3.13?) > --- > kernel/rcupdate.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c > index cce6ba8..4f20c6c 100644 > --- a/kernel/rcupdate.c > +++ b/kernel/rcupdate.c > @@ -122,7 +122,7 @@ struct lockdep_map rcu_sched_lock_map = > STATIC_LOCKDEP_MAP_INIT("rcu_read_lock_sched", &rcu_sched_lock_key); > EXPORT_SYMBOL_GPL(rcu_sched_lock_map); > > -int debug_lockdep_rcu_enabled(void) > +int notrace debug_lockdep_rcu_enabled(void) > { > return rcu_scheduler_active && debug_locks && > current->lockdep_recursion == 0; > -- > 1.7.10.4 > >