From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758188Ab2FOWTc (ORCPT ); Fri, 15 Jun 2012 18:19:32 -0400 Received: from relay4-d.mail.gandi.net ([217.70.183.196]:35168 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758119Ab2FOWTb (ORCPT ); Fri, 15 Jun 2012 18:19:31 -0400 X-Originating-IP: 217.70.178.144 X-Originating-IP: 50.43.46.74 Date: Fri, 15 Jun 2012 15:19:16 -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, patches@linaro.org, "Paul E. McKenney" Subject: Re: [PATCH tip/core/rcu 05/15] rcu: Move _rcu_barrier()'s rcu_head structures to rcu_data structures Message-ID: <20120615221915.GY31184@leaf> References: <20120615210550.GA27506@linux.vnet.ibm.com> <1339794370-28119-1-git-send-email-paulmck@linux.vnet.ibm.com> <1339794370-28119-5-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: <1339794370-28119-5-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 Fri, Jun 15, 2012 at 02:06:00PM -0700, Paul E. McKenney wrote: > From: "Paul E. McKenney" > > In order for multiple flavors of RCU to each concurrently run one > rcu_barrier(), each flavor needs its own per-CPU set of rcu_head > structures. This commit therefore moves _rcu_barrier()'s set of > per-CPU rcu_head structures from per-CPU variables to the existing > per-CPU and per-RCU-flavor rcu_data structures. > > Signed-off-by: Paul E. McKenney > Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett > kernel/rcutree.c | 6 ++---- > kernel/rcutree.h | 3 +++ > 2 files changed, 5 insertions(+), 4 deletions(-) > > diff --git a/kernel/rcutree.c b/kernel/rcutree.c > index 8b3ab4e..2cfbdb8 100644 > --- a/kernel/rcutree.c > +++ b/kernel/rcutree.c > @@ -157,7 +157,6 @@ unsigned long rcutorture_vernum; > > /* State information for rcu_barrier() and friends. */ > > -static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL}; > static atomic_t rcu_barrier_cpu_count; > static DEFINE_MUTEX(rcu_barrier_mutex); > static struct completion rcu_barrier_completion; > @@ -2279,12 +2278,11 @@ static void rcu_barrier_callback(struct rcu_head *notused) > */ > static void rcu_barrier_func(void *type) > { > - int cpu = smp_processor_id(); > - struct rcu_head *head = &per_cpu(rcu_barrier_head, cpu); > struct rcu_state *rsp = type; > + struct rcu_data *rdp = __this_cpu_ptr(rsp->rda); > > atomic_inc(&rcu_barrier_cpu_count); > - rsp->call(head, rcu_barrier_callback); > + rsp->call(&rdp->barrier_head, rcu_barrier_callback); > } > > /* > diff --git a/kernel/rcutree.h b/kernel/rcutree.h > index 15837d7..1783eae 100644 > --- a/kernel/rcutree.h > +++ b/kernel/rcutree.h > @@ -300,6 +300,9 @@ struct rcu_data { > unsigned long n_rp_need_fqs; > unsigned long n_rp_need_nothing; > > + /* 6) _rcu_barrier() callback. */ > + struct rcu_head barrier_head; > + > int cpu; > struct rcu_state *rsp; > }; > -- > 1.7.8 >