From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758149Ab0DOXzE (ORCPT ); Thu, 15 Apr 2010 19:55:04 -0400 Received: from slow3-v.mail.gandi.net ([217.70.178.89]:54466 "EHLO slow3-v.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758042Ab0DOXzB (ORCPT ); Thu, 15 Apr 2010 19:55:01 -0400 X-WhiteListed: mail was accepted with no delay X-WhiteListed: mail was accepted with no delay X-Originating-IP: 217.70.178.44 X-Originating-IP: 173.50.255.69 Date: Thu, 15 Apr 2010 16:52:52 -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, dvhltc@us.ibm.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com Subject: Re: [PATCH RFC tip/core/rcu 02/16] rcu: make dead code really dead Message-ID: <20100415235251.GA2491@feather> References: <20100415181255.GA19588@linux.vnet.ibm.com> <1271355219-20714-2-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: <1271355219-20714-2-git-send-email-paulmck@linux.vnet.ibm.com> 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 Thu, Apr 15, 2010 at 11:13:25AM -0700, Paul E. McKenney wrote: > From: Lai Jiangshan > > cleanup: make dead code really dead > > Signed-off-by: Lai Jiangshan > Signed-off-by: Paul E. McKenney > --- > kernel/rcutree.c | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/rcutree.c b/kernel/rcutree.c > index e54c123..6042fb8 100644 > --- a/kernel/rcutree.c > +++ b/kernel/rcutree.c > @@ -1236,11 +1236,11 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) > break; /* grace period idle or initializing, ignore. */ > > case RCU_SAVE_DYNTICK: > - > - raw_spin_unlock(&rnp->lock); /* irqs remain disabled */ > if (RCU_SIGNAL_INIT != RCU_SAVE_DYNTICK) > break; /* So gcc recognizes the dead code. */ GCC's new __builtin_unreachable would help here, though obviously we can't count on 4.5 or newer quite yet. A wrapper in compiler.h would let us use it when available though. - Josh Triplett