From 7608a43d8f2e02f8b532f8e11481d7ecf8b5d3f9 Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Wed, 30 Jul 2014 13:41:54 -0700 Subject: [PATCH] locking/mutexes: Use MUTEX_SPIN_ON_OWNER when appropriate 4badad35 ("locking/mutex: Disable optimistic spinning on some architectures") added a ARCH_SUPPORTS_ATOMIC_RMW flag to disable the mutex optimistic feature on specific archs. Because CONFIG_MUTEX_SPIN_ON_OWNER only depended on DEBUG and SMP, it was ok to have the ->owner field conditional a bit flexible. However by adding a new variable to the matter, we can waste space with the unused field, ie: CONFIG_SMP && (!CONFIG_MUTEX_SPIN_ON_OWNER && !CONFIG_DEBUG_MUTEX). Signed-off-by: Davidlohr Bueso Acked-by: Jason Low Signed-off-by: Peter Zijlstra Cc: aswin@hp.com Cc: Davidlohr Bueso Cc: Heiko Carstens Cc: Jason Low Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Tim Chen Link: http://lkml.kernel.org/r/1406752916-3341-5-git-send-email-davidlohr@hp.com Signed-off-by: Ingo Molnar --- include/linux/mutex.h | 2 +- kernel/locking/mutex.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/mutex.h b/include/linux/mutex.h index 8d5535c58cc2..e4c29418f407 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -52,7 +52,7 @@ struct mutex { atomic_t count; spinlock_t wait_lock; struct list_head wait_list; -#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_SMP) +#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_MUTEX_SPIN_ON_OWNER) struct task_struct *owner; #endif #ifdef CONFIG_MUTEX_SPIN_ON_OWNER diff --git a/kernel/locking/mutex.h b/kernel/locking/mutex.h index 4115fbf83b12..5cda397607f2 100644 --- a/kernel/locking/mutex.h +++ b/kernel/locking/mutex.h @@ -16,7 +16,7 @@ #define mutex_remove_waiter(lock, waiter, ti) \ __list_del((waiter)->list.prev, (waiter)->list.next) -#ifdef CONFIG_SMP +#ifdef CONFIG_MUTEX_SPIN_ON_OWNER static inline void mutex_set_owner(struct mutex *lock) { lock->owner = current; -- 2.20.1