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lockdep: fixup mutex annotations

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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 <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2007-10-11 22:11:12 +02:00
parent 3aa416b07f
commit e4564f79d4
2 changed files with 26 additions and 18 deletions
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9
include/linux/mutex.h
View file

@ -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

35
kernel/mutex.c
View file

@ -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 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass)
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