From e4564f79d4b6923da7360df4b24a48cc2d4160de Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 11 Oct 2007 22:11:12 +0200 Subject: [PATCH] lockdep: fixup mutex annotations The fancy mutex_lock fastpath has too many indirections to track the caller hence all contentions are perceived to come from mutex_lock(). Avoid this by explicitly not using the fastpath code (it was disabled already anyway). Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- include/linux/mutex.h | 9 ++++++--- kernel/mutex.c | 35 ++++++++++++++++++++--------------- 2 files changed, 26 insertions(+), 18 deletions(-) diff --git a/include/linux/mutex.h b/include/linux/mutex.h index 0d50ea3df6..6a735c72f2 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -120,14 +120,17 @@ static inline int fastcall mutex_is_locked(struct mutex *lock) * See kernel/mutex.c for detailed documentation of these APIs. * Also see Documentation/mutex-design.txt. */ -extern void fastcall mutex_lock(struct mutex *lock); -extern int __must_check fastcall mutex_lock_interruptible(struct mutex *lock); - #ifdef CONFIG_DEBUG_LOCK_ALLOC extern void mutex_lock_nested(struct mutex *lock, unsigned int subclass); extern int __must_check mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass); + +#define mutex_lock(lock) mutex_lock_nested(lock, 0) +#define mutex_lock_interruptible(lock) mutex_lock_interruptible_nested(lock, 0) #else +extern void fastcall mutex_lock(struct mutex *lock); +extern int __must_check fastcall mutex_lock_interruptible(struct mutex *lock); + # define mutex_lock_nested(lock, subclass) mutex_lock(lock) # define mutex_lock_interruptible_nested(lock, subclass) mutex_lock_interruptible(lock) #endif diff --git a/kernel/mutex.c b/kernel/mutex.c index 691b86564d..d7fe50cc55 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -51,6 +51,7 @@ __mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key) EXPORT_SYMBOL(__mutex_init); +#ifndef CONFIG_DEBUG_LOCK_ALLOC /* * We split the mutex lock/unlock logic into separate fastpath and * slowpath functions, to reduce the register pressure on the fastpath. @@ -92,6 +93,7 @@ void inline fastcall __sched mutex_lock(struct mutex *lock) } EXPORT_SYMBOL(mutex_lock); +#endif static void fastcall noinline __sched __mutex_unlock_slowpath(atomic_t *lock_count); @@ -122,7 +124,8 @@ EXPORT_SYMBOL(mutex_unlock); * Lock a mutex (possibly interruptible), slowpath: */ static inline int __sched -__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass) +__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, + unsigned long ip) { struct task_struct *task = current; struct mutex_waiter waiter; @@ -132,7 +135,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass) spin_lock_mutex(&lock->wait_lock, flags); debug_mutex_lock_common(lock, &waiter); - mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_); + mutex_acquire(&lock->dep_map, subclass, 0, ip); debug_mutex_add_waiter(lock, &waiter, task_thread_info(task)); /* add waiting tasks to the end of the waitqueue (FIFO): */ @@ -143,7 +146,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass) if (old_val == 1) goto done; - lock_contended(&lock->dep_map, _RET_IP_); + lock_contended(&lock->dep_map, ip); for (;;) { /* @@ -166,7 +169,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass) if (unlikely(state == TASK_INTERRUPTIBLE && signal_pending(task))) { mutex_remove_waiter(lock, &waiter, task_thread_info(task)); - mutex_release(&lock->dep_map, 1, _RET_IP_); + mutex_release(&lock->dep_map, 1, ip); spin_unlock_mutex(&lock->wait_lock, flags); debug_mutex_free_waiter(&waiter); @@ -197,20 +200,12 @@ done: return 0; } -static void fastcall noinline __sched -__mutex_lock_slowpath(atomic_t *lock_count) -{ - struct mutex *lock = container_of(lock_count, struct mutex, count); - - __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0); -} - #ifdef CONFIG_DEBUG_LOCK_ALLOC void __sched mutex_lock_nested(struct mutex *lock, unsigned int subclass) { might_sleep(); - __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass); + __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass, _RET_IP_); } EXPORT_SYMBOL_GPL(mutex_lock_nested); @@ -219,7 +214,7 @@ int __sched mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass) { might_sleep(); - return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, subclass); + return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, subclass, _RET_IP_); } EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested); @@ -271,6 +266,7 @@ __mutex_unlock_slowpath(atomic_t *lock_count) __mutex_unlock_common_slowpath(lock_count, 1); } +#ifndef CONFIG_DEBUG_LOCK_ALLOC /* * Here come the less common (and hence less performance-critical) APIs: * mutex_lock_interruptible() and mutex_trylock(). @@ -298,13 +294,22 @@ int fastcall __sched mutex_lock_interruptible(struct mutex *lock) EXPORT_SYMBOL(mutex_lock_interruptible); +static void fastcall noinline __sched +__mutex_lock_slowpath(atomic_t *lock_count) +{ + struct mutex *lock = container_of(lock_count, struct mutex, count); + + __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, _RET_IP_); +} + static int fastcall noinline __sched __mutex_lock_interruptible_slowpath(atomic_t *lock_count) { struct mutex *lock = container_of(lock_count, struct mutex, count); - return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0); + return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0, _RET_IP_); } +#endif /* * Spinlock based trylock, we take the spinlock and check whether we -- 2.39.5