From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758948Ab3IFBtn (ORCPT ); Thu, 5 Sep 2013 21:49:43 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:10577 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758759Ab3IFBtQ (ORCPT ); Thu, 5 Sep 2013 21:49:16 -0400 X-Authority-Analysis: v=2.0 cv=V4T/IJbi c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=Ciwy3NGCPMMA:10 a=wcXYPUs7a-oA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=sIsxsRJOc_QA:10 a=VnNF1IyMAAAA:8 a=ADIRIkwvCkhWOhZfK5QA:9 a=jeBq3FmKZ4MA:10 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Message-Id: <20130906014915.603795285@goodmis.org> User-Agent: quilt/0.60-1 Date: Thu, 05 Sep 2013 21:48:20 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Frederic Weisbecker , Andrew Morton , Peter Zijlstra , "Paul E. McKenney" , Dave Jones Subject: [for-next][PATCH 4/4] ftrace/rcu: Do not trace debug_lockdep_rcu_enabled() References: <20130906014816.037690469@goodmis.org> Content-Disposition: inline; filename=0004-ftrace-rcu-Do-not-trace-debug_lockdep_rcu_enabled.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Reviewed-by: Paul E. McKenney Signed-off-by: Steven Rostedt --- 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