From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932251Ab2FOWzc (ORCPT ); Fri, 15 Jun 2012 18:55:32 -0400 Received: from relay3-d.mail.gandi.net ([217.70.183.195]:59355 "EHLO relay3-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758171Ab2FOWzb (ORCPT ); Fri, 15 Jun 2012 18:55:31 -0400 X-Originating-IP: 217.70.178.129 X-Originating-IP: 50.43.46.74 Date: Fri, 15 Jun 2012 15:55:17 -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 08/15] rcu: Move rcu_barrier_mutex to rcu_state structure Message-ID: <20120615225516.GD5226@leaf> References: <20120615210550.GA27506@linux.vnet.ibm.com> <1339794370-28119-1-git-send-email-paulmck@linux.vnet.ibm.com> <1339794370-28119-8-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: <1339794370-28119-8-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 02:06:03PM -0700, Paul E. McKenney wrote: > From: "Paul E. McKenney" > > In order to allow each RCU flavor to concurrently execute its > rcu_barrier() function, it is necessary to move the relevant > state to the rcu_state structure. This commit therefore moves the > rcu_barrier_mutex global variable to a new ->barrier_mutex field > in the rcu_state structure. > > Signed-off-by: Paul E. McKenney > Signed-off-by: Paul E. McKenney > --- > kernel/rcutree.c | 11 +++-------- > kernel/rcutree.h | 1 + > 2 files changed, 4 insertions(+), 8 deletions(-) > > diff --git a/kernel/rcutree.c b/kernel/rcutree.c > index a946437..93358d4 100644 > --- a/kernel/rcutree.c > +++ b/kernel/rcutree.c > @@ -71,9 +71,8 @@ static struct lock_class_key rcu_node_class[RCU_NUM_LVLS]; > .onofflock = __RAW_SPIN_LOCK_UNLOCKED(&sname##_state.onofflock), \ > .orphan_nxttail = &sname##_state.orphan_nxtlist, \ > .orphan_donetail = &sname##_state.orphan_donelist, \ > + .barrier_mutex = __MUTEX_INITIALIZER(sname##_state.barrier_mutex), \ > .fqslock = __RAW_SPIN_LOCK_UNLOCKED(&sname##_state.fqslock), \ > - .n_force_qs = 0, \ > - .n_force_qs_ngp = 0, \ The removal of these two fields seems unrelated to the rest of this commit. I assume you've removed them because the use of "static" makes initializations to 0 unnecessary? The rest of this commit seems fine to me. > .name = #sname, \ > } > > @@ -155,10 +154,6 @@ static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp); > unsigned long rcutorture_testseq; > unsigned long rcutorture_vernum; > > -/* State information for rcu_barrier() and friends. */ > - > -static DEFINE_MUTEX(rcu_barrier_mutex); > - > /* > * Return true if an RCU grace period is in progress. The ACCESS_ONCE()s > * permit this function to be invoked without holding the root rcu_node > @@ -2300,7 +2295,7 @@ static void _rcu_barrier(struct rcu_state *rsp) > init_rcu_head_on_stack(&rd.barrier_head); > > /* Take mutex to serialize concurrent rcu_barrier() requests. */ > - mutex_lock(&rcu_barrier_mutex); > + mutex_lock(&rsp->barrier_mutex); > > smp_mb(); /* Prevent any prior operations from leaking in. */ > > @@ -2377,7 +2372,7 @@ static void _rcu_barrier(struct rcu_state *rsp) > wait_for_completion(&rsp->barrier_completion); > > /* Other rcu_barrier() invocations can now safely proceed. */ > - mutex_unlock(&rcu_barrier_mutex); > + mutex_unlock(&rsp->barrier_mutex); > > destroy_rcu_head_on_stack(&rd.barrier_head); > } > diff --git a/kernel/rcutree.h b/kernel/rcutree.h > index 56fb8d4..d9ac82f 100644 > --- a/kernel/rcutree.h > +++ b/kernel/rcutree.h > @@ -386,6 +386,7 @@ struct rcu_state { > struct task_struct *rcu_barrier_in_progress; > /* Task doing rcu_barrier(), */ > /* or NULL if no barrier. */ > + struct mutex barrier_mutex; /* Guards barrier fields. */ > atomic_t barrier_cpu_count; /* # CPUs waiting on. */ > struct completion barrier_completion; /* Wake at barrier end. */ > raw_spinlock_t fqslock; /* Only one task forcing */ > -- > 1.7.8 >