Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934181Ab2KBSLE (ORCPT ); Fri, 2 Nov 2012 14:11:04 -0400 Received: from e37.co.us.ibm.com ([32.97.110.158]:60559 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933602Ab2KBSLC (ORCPT ); Fri, 2 Nov 2012 14:11:02 -0400 Date: Fri, 2 Nov 2012 11:10:26 -0700 From: "Paul E. McKenney" To: Shan Wei Cc: dipankar@in.ibm.com, Kernel-Maillist , cl@linux-foundation.org Subject: Re: [PATCH v2 6/9] rcu: use __this_cpu_read helper instead of per_cpu_ptr(p, raw_smp_processor_id()) Message-ID: <20121102181026.GY3027@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <5093EE6B.3070906@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5093EE6B.3070906@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12110218-7408-0000-0000-000009EA04B4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1450 Lines: 44 On Sat, Nov 03, 2012 at 12:01:47AM +0800, Shan Wei wrote: > From: Shan Wei > > Signed-off-by: Shan Wei > --- > kernel/rcutree.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/kernel/rcutree.c b/kernel/rcutree.c > index 74df86b..441b945 100644 > --- a/kernel/rcutree.c > +++ b/kernel/rcutree.c > @@ -1960,7 +1960,7 @@ static void force_quiescent_state(struct rcu_state *rsp) > struct rcu_node *rnp_old = NULL; > > /* Funnel through hierarchy to reduce memory contention. */ > - rnp = per_cpu_ptr(rsp->rda, raw_smp_processor_id())->mynode; > + rnp = __this_cpu_read(rsp->rda->mynode); OK, I'll bite... Why this instead of: rnp = __this_cpu_read(rsp->rda)->mynode; Thanx, Paul > for (; rnp != NULL; rnp = rnp->parent) { > ret = (ACCESS_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) || > !raw_spin_trylock(&rnp->fqslock); > -- > 1.7.1 > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/