From 5db6c6fefb1ca0e81e3bd6dd8998bf51c453d823 Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Fri, 11 Jul 2014 14:00:06 -0700 Subject: [PATCH] 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. Signed-off-by: Davidlohr Bueso Acked-by: Jason Low [ Also make it depend on ARCH_SUPPORTS_ATOMIC_RMW. ] Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1405112406-13052-2-git-send-email-davidlohr@hp.com Cc: aswin@hp.com Cc: Chris Mason Cc: Davidlohr Bueso Cc: Josef Bacik Cc: Linus Torvalds Cc: Waiman Long Signed-off-by: Ingo Molnar Signed-off-by: Ingo Molnar --- include/linux/rwsem.h | 6 ++++-- kernel/Kconfig.locks | 4 ++++ kernel/locking/rwsem-xadd.c | 4 ++-- kernel/locking/rwsem.c | 2 +- 4 files changed, 11 insertions(+), 5 deletions(-) diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 716807f0eb2d..035d3c57fc8a 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -14,7 +14,9 @@ #include #include #include +#ifdef CONFIG_RWSEM_SPIN_ON_OWNER #include +#endif struct rw_semaphore; @@ -26,7 +28,7 @@ struct rw_semaphore { long count; struct list_head wait_list; raw_spinlock_t wait_lock; -#ifdef CONFIG_SMP +#ifdef CONFIG_RWSEM_SPIN_ON_OWNER struct optimistic_spin_queue osq; /* spinner MCS lock */ /* * Write owner. Used as a speculative check to see @@ -63,7 +65,7 @@ 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_OPT_INIT(lockname) , .osq = OSQ_LOCK_UNLOCKED, .owner = NULL #else #define __RWSEM_OPT_INIT(lockname) diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks index 81907941d921..76768ee812b2 100644 --- a/kernel/Kconfig.locks +++ b/kernel/Kconfig.locks @@ -227,6 +227,10 @@ config MUTEX_SPIN_ON_OWNER def_bool y depends on SMP && !DEBUG_MUTEXES && ARCH_SUPPORTS_ATOMIC_RMW +config RWSEM_SPIN_ON_OWNER + def_bool y + depends on SMP && RWSEM_XCHGADD_ALGORITHM && ARCH_SUPPORTS_ATOMIC_RMW + config ARCH_USE_QUEUE_RWLOCK bool diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index 7190592c2645..a2391ac135c8 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; osq_lock_init(&sem->osq); #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 42f806de49d4..e2d3bc7f03b4 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; -- 2.39.2