Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932274Ab2JOV4i (ORCPT ); Mon, 15 Oct 2012 17:56:38 -0400 Received: from e37.co.us.ibm.com ([32.97.110.158]:50984 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755127Ab2JOV4f (ORCPT ); Mon, 15 Oct 2012 17:56:35 -0400 Date: Mon, 15 Oct 2012 14:56:08 -0700 From: "Paul E. McKenney" To: Lai Jiangshan Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/4] srcu: add DEFINE_SRCU() Message-ID: <20121015215607.GB3010@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <1350062057-2439-1-git-send-email-laijs@cn.fujitsu.com> <1350062057-2439-4-git-send-email-laijs@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1350062057-2439-4-git-send-email-laijs@cn.fujitsu.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12101521-7408-0000-0000-0000095DBC6B Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3551 Lines: 96 On Sat, Oct 13, 2012 at 01:14:16AM +0800, Lai Jiangshan wrote: > In old days, we have two different API sets for dynamic-allocated per_cpu data > and DEFINE_PER_CPU()-defined per_cpu data, and since we used > dynamic-allocated per_cpu data, we can't use DEFINE_PER_CPU()-defined > per_cpu data(otherwise we will introduce a lot of duplicated code. > > In new days, we have only one API sets for both type of per_cpu data, > so we can use DEFINE_PER_CPU() for DEFINE_SRCU() which allows us > define and init srcu struct in build time and allows us use srcu APIs > in very early boot time. > > We also provide DEFINE_STATIC_SRCU() which defines an internal srcu struct > inside a single *.c. > > Signed-off-by: Lai Jiangshan > --- > include/linux/srcu.h | 30 ++++++++++++++++++++++++++++++ > 1 files changed, 30 insertions(+), 0 deletions(-) > > diff --git a/include/linux/srcu.h b/include/linux/srcu.h > index 5cce128..f986df1 100644 > --- a/include/linux/srcu.h > +++ b/include/linux/srcu.h > @@ -42,6 +42,8 @@ struct rcu_batch { > struct rcu_head *head, **tail; > }; > > +#define RCU_BATCH_INIT(name) { NULL, &(name.head) } > + > struct srcu_struct { > unsigned completed; > struct srcu_struct_array __percpu *per_cpu_ref; > @@ -72,14 +74,42 @@ int __init_srcu_struct(struct srcu_struct *sp, const char *name, > __init_srcu_struct((sp), #sp, &__srcu_key); \ > }) > > +#define __SRCU_DEP_MAP_INIT(srcu_name) .dep_map = { .name = #srcu_name }, > #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ > > int init_srcu_struct(struct srcu_struct *sp); > > +#define __SRCU_DEP_MAP_INIT(srcu_name) > #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ > > void process_srcu(struct work_struct *work); > > +#define __SRCU_STRUCT_INIT(name) \ > + { \ > + .completed = -300, \ > + .per_cpu_ref = &name##_srcu_array, \ > + .queue_lock = __SPIN_LOCK_UNLOCKED(name.queue_lock), \ > + .running = false, \ > + .batch_queue = RCU_BATCH_INIT(name.batch_queue), \ > + .batch_check0 = RCU_BATCH_INIT(name.batch_check0), \ > + .batch_check1 = RCU_BATCH_INIT(name.batch_check1), \ > + .batch_done = RCU_BATCH_INIT(name.batch_done), \ > + .work = __DELAYED_WORK_INITIALIZER(name.work, process_srcu),\ > + __SRCU_DEP_MAP_INIT(name) \ > + } > + > +/* > + * define and init a srcu struct at build time. > + * dont't call init_srcu_struct() nor cleanup_srcu_struct() on it. > + */ > +#define DEFINE_SRCU(name) \ > + static DEFINE_PER_CPU(struct srcu_struct_array, name##_srcu_array);\ > + struct srcu_struct name = __SRCU_STRUCT_INIT(name); > + > +#define DEFINE_STATIC_SRCU(name) \ > + static DEFINE_PER_CPU(struct srcu_struct_array, name##_srcu_array);\ > + static struct srcu_struct name = __SRCU_STRUCT_INIT(name); > + Why not collapse DEFINE_SRCU() and DEFINE_STATIC_SRCU() as follows? +#define DEFINE_SRCU(name) \ + struct srcu_struct name = __SRCU_STRUCT_INIT(name); \ + static DEFINE_PER_CPU(struct srcu_struct_array, name##_srcu_array); Then "static DEFINE_SRCU(foo)" would create a static srcu_struct without the need for a separate DEFINE_STATIC_SRCU(). Thanx, Paul > /** > * call_srcu() - Queue a callback for invocation after an SRCU grace period > * @sp: srcu_struct in queue the callback > -- > 1.7.7.6 > -- 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/