From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934456AbZLPBg0 (ORCPT ); Tue, 15 Dec 2009 20:36:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934381AbZLPBgZ (ORCPT ); Tue, 15 Dec 2009 20:36:25 -0500 Received: from slow3-v.mail.gandi.net ([217.70.178.89]:45998 "EHLO slow3-v.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932279AbZLPBgZ (ORCPT ); Tue, 15 Dec 2009 20:36:25 -0500 Date: Tue, 15 Dec 2009 16:59:59 -0800 From: Josh Triplett To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, dvhltc@us.ibm.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com Subject: Re: [PATCH RFC tip/core/rcu 15/18] rcu: give different levels of the rcu_node hierarchy distinct lockdep names Message-ID: <20091216005959.GC2408@feather> References: <20091215230213.GA9093@linux.vnet.ibm.com> <12609181611666-git-send-email-> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <12609181611666-git-send-email-> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 15, 2009 at 03:02:38PM -0800, Paul E. McKenney wrote: > From: Paul E. McKenney > > Proposed for 2.6.34, not for inclusion. > > Previously, each level of the rcu_node hierarchy had the same rather > unimaginative name: "&rcu_node_class[i]". This makes lockdep diagnostics > involving these lockdep classes less helpful than would be nice. This > patch fixes this by giving each level of the rcu_node hierarchy a distinct > name: "rcu_node_level_0", "rcu_node_level_1", and so on. > > Signed-off-by: Paul E. McKenney > --- > kernel/rcutree.c | 9 ++++++++- > 1 files changed, 8 insertions(+), 1 deletions(-) > > diff --git a/kernel/rcutree.c b/kernel/rcutree.c > index 0a4c328..a6e45f6 100644 > --- a/kernel/rcutree.c > +++ b/kernel/rcutree.c > @@ -1811,11 +1811,17 @@ static void __init rcu_init_levelspread(struct rcu_state *rsp) > */ > static void __init rcu_init_one(struct rcu_state *rsp) > { > + static char *buf[] = { "rcu_node_level_0", > + "rcu_node_level_1", > + "rcu_node_level_2", > + "rcu_node_level_3" }; /* Match MAX_RCU_LVLS */ > int cpustride = 1; > int i; > int j; > struct rcu_node *rnp; > > + WARN_ON_ONCE(MAX_RCU_LVLS > 4); /* Fix buf[] initialization! */ > + BUILD_BUG_ON seems better. For that matter, please consider moving these near the rest of the level-specific defines, making them const, and ideally not emitting the strings for levels you don't have. - Josh Triplett