Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752201AbaFFSs0 (ORCPT ); Fri, 6 Jun 2014 14:48:26 -0400 Received: from g5t1627.atlanta.hp.com ([15.192.137.10]:58795 "EHLO g5t1627.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751363AbaFFSsZ (ORCPT ); Fri, 6 Jun 2014 14:48:25 -0400 Message-ID: <1402080497.14433.8.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 11:48:17 -0700 In-Reply-To: <1402078358.14433.3.camel@buesod1.americas.hpqcorp.net> 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> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.4 (3.6.4-3.fc18) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2014-06-06 at 11:12 -0700, Davidlohr Bueso wrote: > On Fri, 2014-06-06 at 10:13 -0700, Jason Low wrote: > > On Fri, 2014-06-06 at 08:55 -0700, Davidlohr Bueso wrote: > > > 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. > > > > > > Signed-off-by: Davidlohr Bueso > > > --- > > > include/linux/rwsem.h | 4 ++-- > > > kernel/Kconfig.locks | 4 ++++ > > > kernel/locking/rwsem.c | 2 +- > > > 3 files changed, 7 insertions(+), 3 deletions(-) > > > > Do we also want to add an #ifdef CONFIG_RWSEM_SPIN_ON_OWNER in > > __init_rwsem() and in the optimistic spinning functions for rwsem-xadd? > > > > Not really, as we conditionally build rwsem-xadd.o based on > CONFIG_RWSEM_XCHGADD_ALGORITHM: > > obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o > obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o > > So leaving just SMP is ok there. Of course that's bogus when we add more dependencies (ie 2/2), so yeah, we need to add the whole CONFIG_RWSEM_SPIN_ON_OWNER option. Thanks. 8<--------------------------------------------------------- From: Davidlohr Bueso Date: Fri, 6 Jun 2014 11:45:34 -0700 Subject: [PATCH v2 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 | 2 +- kernel/locking/rwsem.c | 2 +- 4 files changed, 8 insertions(+), 4 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..f6b5b96 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 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; -- 1.8.1.4 -- 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/