From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755298AbaGWM24 (ORCPT ); Wed, 23 Jul 2014 08:28:56 -0400 Received: from e32.co.us.ibm.com ([32.97.110.150]:49029 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754763AbaGWM2y (ORCPT ); Wed, 23 Jul 2014 08:28:54 -0400 Date: Wed, 23 Jul 2014 05:28:49 -0700 From: "Paul E. McKenney" To: Pranith Kumar Cc: Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , "open list:READ-COPY UPDATE..." Subject: Re: [PATCH 15/16] rcu: Check for a nocb cpu before trying to spawn nocb threads Message-ID: <20140723122849.GN11241@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <1406092194-13004-1-git-send-email-bobby.prani@gmail.com> <1406092194-13004-16-git-send-email-bobby.prani@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1406092194-13004-16-git-send-email-bobby.prani@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14072312-0928-0000-0000-0000039B2B99 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 23, 2014 at 01:09:52AM -0400, Pranith Kumar wrote: > This commit tries to spawn nocb kthreads only when the CPU is marked as a nocb > cpu. This is a minor optimization. > > Signed-off-by: Pranith Kumar This only happens once at boot time, so I am happier with the single check at the bottom. So sorry, but no. Thanx, Paul > --- > kernel/rcu/tree_plugin.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h > index 541c776..8abff0a 100644 > --- a/kernel/rcu/tree_plugin.h > +++ b/kernel/rcu/tree_plugin.h > @@ -1490,7 +1490,8 @@ static void rcu_prepare_kthreads(int cpu) > return; > > rcu_spawn_one_boost_kthread(rcu_state_p, rnp); > - rcu_spawn_all_nocb_kthreads(cpu); > + if (rcu_is_nocb_cpu(cpu)) > + rcu_spawn_all_nocb_kthreads(cpu); > } > > #else /* #ifdef CONFIG_RCU_BOOST */ > -- > 2.0.0.rc2 >