Messages in this thread Patch in this message | | | Subject | Re: [PATCH 1/2] locking/rwsem: Add CONFIG_RWSEM_SPIN_ON_OWNER | From | Davidlohr Bueso <> | Date | Fri, 06 Jun 2014 12:20:41 -0700 |
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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 <davidlohr@hp.com> 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 <jason.low2@hp.com> Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> --- 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 <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
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