From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756223Ab2ICJmM (ORCPT ); Mon, 3 Sep 2012 05:42:12 -0400 Received: from relay3-d.mail.gandi.net ([217.70.183.195]:45406 "EHLO relay3-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755695Ab2ICJmL (ORCPT ); Mon, 3 Sep 2012 05:42:11 -0400 X-Originating-IP: 217.70.178.138 X-Originating-IP: 50.43.46.74 Date: Mon, 3 Sep 2012 02:42:03 -0700 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, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu, patches@linaro.org Subject: Re: [PATCH tip/core/rcu 19/23] rcu: Adjust for unconditional ->completed assignment Message-ID: <20120903094203.GH5574@leaf> References: <20120830181811.GA29154@linux.vnet.ibm.com> <1346350718-30937-1-git-send-email-paulmck@linux.vnet.ibm.com> <1346350718-30937-19-git-send-email-paulmck@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1346350718-30937-19-git-send-email-paulmck@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 30, 2012 at 11:18:34AM -0700, Paul E. McKenney wrote: > From: "Paul E. McKenney" > > Now that the rcu_node structures' ->completed fields are unconditionally > assigned at grace-period cleanup time, they should already have the > correct value for the new grace period at grace-period initialization > time. This commit therefore inserts a WARN_ON_ONCE() to verify this > invariant. > > Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett > kernel/rcutree.c | 4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > diff --git a/kernel/rcutree.c b/kernel/rcutree.c > index 1373388..86903df 100644 > --- a/kernel/rcutree.c > +++ b/kernel/rcutree.c > @@ -1098,6 +1098,7 @@ static int rcu_gp_init(struct rcu_state *rsp) > rcu_preempt_check_blocked_tasks(rnp); > rnp->qsmask = rnp->qsmaskinit; > rnp->gpnum = rsp->gpnum; > + WARN_ON_ONCE(rnp->completed != rsp->completed); > rnp->completed = rsp->completed; > if (rnp == rdp->mynode) > rcu_start_gp_per_cpu(rsp, rnp, rdp); > @@ -2795,7 +2796,8 @@ static void __init rcu_init_one(struct rcu_state *rsp, > raw_spin_lock_init(&rnp->fqslock); > lockdep_set_class_and_name(&rnp->fqslock, > &rcu_fqs_class[i], fqs[i]); > - rnp->gpnum = 0; > + rnp->gpnum = rsp->gpnum; > + rnp->completed = rsp->completed; > rnp->qsmask = 0; > rnp->qsmaskinit = 0; > rnp->grplo = j * cpustride; > -- > 1.7.8 >