From patchwork Fri Jun 6 19:20:41 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Davidlohr Bueso X-Patchwork-Id: 4313441 Return-Path: X-Original-To: patchwork-linux-parisc@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 20C66BEEAA for ; Fri, 6 Jun 2014 19:20:50 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 29DFF20265 for ; Fri, 6 Jun 2014 19:20:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 24D4B20274 for ; Fri, 6 Jun 2014 19:20:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751856AbaFFTUr (ORCPT ); Fri, 6 Jun 2014 15:20:47 -0400 Received: from g2t2354.austin.hp.com ([15.217.128.53]:57763 "EHLO g2t2354.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751821AbaFFTUr (ORCPT ); Fri, 6 Jun 2014 15:20:47 -0400 X-Greylist: delayed 13098 seconds by postgrey-1.27 at vger.kernel.org; Fri, 06 Jun 2014 15:20:47 EDT Received: from g2t2360.austin.hp.com (g2t2360.austin.hp.com [16.197.8.247]) by g2t2354.austin.hp.com (Postfix) with ESMTP id 309731AB; Fri, 6 Jun 2014 19:20:46 +0000 (UTC) Received: from [16.212.160.243] (unknown [16.212.160.243]) by g2t2360.austin.hp.com (Postfix) with ESMTP id EFE2E49; Fri, 6 Jun 2014 19:20:42 +0000 (UTC) Message-ID: <1402082441.14433.12.camel@buesod1.americas.hpqcorp.net> Subject: Re: [PATCH 1/2] locking/rwsem: Add CONFIG_RWSEM_SPIN_ON_OWNER From: Davidlohr Bueso To: Jason Low Cc: peterz@infradead.org, mingo@kernel.org, mpatocka@redhat.com, torvalds@linux-foundation.org, waiman.long@hp.com, jejb@parisc-linux.org, paulmck@linux.vnet.ibm.com, dave.anglin@bell.net, aswin@hp.com, linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org Date: Fri, 06 Jun 2014 12:20:41 -0700 In-Reply-To: <1402081726.6680.61.camel@j-VirtualBox> References: <1402070140-15090-1-git-send-email-davidlohr@hp.com> <1402070140-15090-2-git-send-email-davidlohr@hp.com> <1402074788.6680.50.camel@j-VirtualBox> <1402078358.14433.3.camel@buesod1.americas.hpqcorp.net> <1402080497.14433.8.camel@buesod1.americas.hpqcorp.net> <1402081726.6680.61.camel@j-VirtualBox> X-Mailer: Evolution 3.6.4 (3.6.4-3.fc18) Mime-Version: 1.0 Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On Fri, 2014-06-06 at 12:08 -0700, Jason Low wrote: > And should we also change that in the optimistic spinning functions so > that it defaults to: > > static bool rwsem_optimistic_spin(struct rw_semaphore *sem) > { > return false; > } Oops Yep, afaict the last offending user. 8<---------------------------------- From: Davidlohr Bueso Date: Fri, 6 Jun 2014 12:15:03 -0700 Subject: [PATCH v3 1/2] locking/rwsem: Add CONFIG_RWSEM_SPIN_ON_OWNER Just like with mutexes (CONFIG_MUTEX_SPIN_ON_OWNER), encapsulate the dependencies for rwsem optimistic spinning. No logical changes here as it continues to depend on both SMP and the XADD algorithm variant. Acked-by: Jason Low Signed-off-by: Davidlohr Bueso --- include/linux/rwsem.h | 4 ++-- kernel/Kconfig.locks | 4 ++++ kernel/locking/rwsem-xadd.c | 4 ++-- kernel/locking/rwsem.c | 2 +- 4 files changed, 9 insertions(+), 5 deletions(-) diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 8d79708..accdef7 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -27,7 +27,7 @@ struct rw_semaphore { long count; raw_spinlock_t wait_lock; struct list_head wait_list; -#ifdef CONFIG_SMP +#ifdef CONFIG_RWSEM_SPIN_ON_OWNER /* * Write owner. Used as a speculative check to see * if the owner is running on the cpu. @@ -64,7 +64,7 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem) # define __RWSEM_DEP_MAP_INIT(lockname) #endif -#if defined(CONFIG_SMP) && !defined(CONFIG_RWSEM_GENERIC_SPINLOCK) +#ifdef CONFIG_RWSEM_SPIN_ON_OWNER #define __RWSEM_INITIALIZER(name) \ { RWSEM_UNLOCKED_VALUE, \ __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock), \ diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks index 35536d9..e4c3162 100644 --- a/kernel/Kconfig.locks +++ b/kernel/Kconfig.locks @@ -224,6 +224,10 @@ config MUTEX_SPIN_ON_OWNER def_bool y depends on SMP && !DEBUG_MUTEXES +config RWSEM_SPIN_ON_OWNER + def_bool y + depends on SMP && RWSEM_XCHGADD_ALGORITHM + config ARCH_USE_QUEUE_RWLOCK bool diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index dacc321..abe6e06 100644 --- a/kernel/locking/rwsem-xadd.c +++ b/kernel/locking/rwsem-xadd.c @@ -82,7 +82,7 @@ void __init_rwsem(struct rw_semaphore *sem, const char *name, sem->count = RWSEM_UNLOCKED_VALUE; raw_spin_lock_init(&sem->wait_lock); INIT_LIST_HEAD(&sem->wait_list); -#ifdef CONFIG_SMP +#ifdef CONFIG_RWSEM_SPIN_ON_OWNER sem->owner = NULL; sem->osq = NULL; #endif @@ -262,7 +262,7 @@ static inline bool rwsem_try_write_lock(long count, struct rw_semaphore *sem) return false; } -#ifdef CONFIG_SMP +#ifdef CONFIG_RWSEM_SPIN_ON_OWNER /* * Try to acquire write lock before the writer has been put on wait queue. */ diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 42f806d..e2d3bc7 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -12,7 +12,7 @@ #include -#if defined(CONFIG_SMP) && defined(CONFIG_RWSEM_XCHGADD_ALGORITHM) +#ifdef CONFIG_RWSEM_SPIN_ON_OWNER static inline void rwsem_set_owner(struct rw_semaphore *sem) { sem->owner = current;