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 <[email protected]> Signed-off-by: Davidlohr Bueso <[email protected]> --- Based on previous discussion (https://lkml.org/lkml/2014/6/6/461): rebased & included ifdefs around #include <linux/osq_lock.h> 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 5d40884..03dbec7 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -14,7 +14,9 @@ #include <linux/list.h> #include <linux/spinlock.h> #include <linux/atomic.h> +#ifdef CONFIG_RWSEM_SPIN_ON_OWNER #include <linux/osq_lock.h> +#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) , .owner = NULL, .osq = { ATOMIC_INIT(OSQ_UNLOCKED_VAL) } #else #define __RWSEM_OPT_INIT(lockname) 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 a673bba..b3d0e9f 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; atomic_set(&sem->osq.tail, OSQ_UNLOCKED_VAL); #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 <linux/atomic.h> -#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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
