Commit 51d7a054521d for kernel
commit 51d7a054521de7085783a9a1ba15c3530863409a
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed Nov 5 15:23:50 2025 +0100
locking/mutex: Redo __mutex_init() to reduce generated code size
mutex_init() invokes __mutex_init() providing the name of the lock and
a pointer to a the lock class. With LOCKDEP enabled this information is
useful but without LOCKDEP it not used at all. Passing the pointer
information of the lock class might be considered negligible but the
name of the lock is passed as well and the string is stored. This
information is wasting storage.
Split __mutex_init() into a _genereic() variant doing the initialisation
of the lock and a _lockdep() version which does _genereic() plus the
lockdep bits. Restrict the lockdep version to lockdep enabled builds
allowing the compiler to remove the unused parameter.
This results in the following size reduction:
text data bss dec filename
| 30237599 8161430 1176624 39575653 vmlinux.defconfig
| 30233269 8149142 1176560 39558971 vmlinux.defconfig.patched
-4.2KiB -12KiB
| 32455099 8471098 12934684 53860881 vmlinux.defconfig.lockdep
| 32455100 8471098 12934684 53860882 vmlinux.defconfig.patched.lockdep
| 27152407 7191822 2068040 36412269 vmlinux.defconfig.preempt_rt
| 27145937 7183630 2067976 36397543 vmlinux.defconfig.patched.preempt_rt
-6.3KiB -8KiB
| 29382020 7505742 13784608 50672370 vmlinux.defconfig.preempt_rt.lockdep
| 29376229 7505742 13784544 50666515 vmlinux.defconfig.patched.preempt_rt.lockdep
-5.6KiB
[peterz: folded fix from boqun]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Link: https://lkml.kernel.org/r/20251125145425.68319-1-boqun.feng@gmail.com
Link: https://patch.msgid.link/20251105142350.Tfeevs2N@linutronix.de
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index 847b81ca6436..bf535f0118bb 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -86,8 +86,23 @@ do { \
#define DEFINE_MUTEX(mutexname) \
struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
-extern void __mutex_init(struct mutex *lock, const char *name,
- struct lock_class_key *key);
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void mutex_init_lockep(struct mutex *lock, const char *name, struct lock_class_key *key);
+
+static inline void __mutex_init(struct mutex *lock, const char *name,
+ struct lock_class_key *key)
+{
+ mutex_init_lockep(lock, name, key);
+}
+#else
+extern void mutex_init_generic(struct mutex *lock);
+
+static inline void __mutex_init(struct mutex *lock, const char *name,
+ struct lock_class_key *key)
+{
+ mutex_init_generic(lock);
+}
+#endif /* !CONFIG_DEBUG_LOCK_ALLOC */
/**
* mutex_is_locked - is the mutex locked
@@ -111,17 +126,27 @@ extern bool mutex_is_locked(struct mutex *lock);
#define DEFINE_MUTEX(mutexname) \
struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
-extern void __mutex_rt_init(struct mutex *lock, const char *name,
- struct lock_class_key *key);
-
#define mutex_is_locked(l) rt_mutex_base_is_locked(&(l)->rtmutex)
-#define __mutex_init(mutex, name, key) \
-do { \
- rt_mutex_base_init(&(mutex)->rtmutex); \
- __mutex_rt_init((mutex), name, key); \
-} while (0)
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+extern void mutex_rt_init_lockdep(struct mutex *mutex, const char *name,
+ struct lock_class_key *key);
+
+static inline void __mutex_init(struct mutex *lock, const char *name,
+ struct lock_class_key *key)
+{
+ mutex_rt_init_lockdep(lock, name, key);
+}
+#else
+extern void mutex_rt_init_generic(struct mutex *mutex);
+
+static inline void __mutex_init(struct mutex *lock, const char *name,
+ struct lock_class_key *key)
+{
+ mutex_rt_init_generic(lock);
+}
+#endif /* !CONFIG_LOCKDEP */
#endif /* CONFIG_PREEMPT_RT */
#ifdef CONFIG_DEBUG_MUTEXES
diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
index 949103fd8e9b..2c6b02d4699b 100644
--- a/kernel/locking/mutex-debug.c
+++ b/kernel/locking/mutex-debug.c
@@ -78,16 +78,8 @@ void debug_mutex_unlock(struct mutex *lock)
}
}
-void debug_mutex_init(struct mutex *lock, const char *name,
- struct lock_class_key *key)
+void debug_mutex_init(struct mutex *lock)
{
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- /*
- * Make sure we are not reinitializing a held lock:
- */
- debug_check_no_locks_freed((void *)lock, sizeof(*lock));
- lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_SLEEP);
-#endif
lock->magic = lock;
}
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index de7d6702cd96..2a1d165b3167 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -43,8 +43,7 @@
# define MUTEX_WARN_ON(cond)
#endif
-void
-__mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
+static void __mutex_init_generic(struct mutex *lock)
{
atomic_long_set(&lock->owner, 0);
raw_spin_lock_init(&lock->wait_lock);
@@ -52,10 +51,8 @@ __mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
osq_lock_init(&lock->osq);
#endif
-
- debug_mutex_init(lock, name, key);
+ debug_mutex_init(lock);
}
-EXPORT_SYMBOL(__mutex_init);
static inline struct task_struct *__owner_task(unsigned long owner)
{
@@ -142,6 +139,11 @@ static inline bool __mutex_trylock(struct mutex *lock)
* There is nothing that would stop spreading the lockdep annotations outwards
* except more code.
*/
+void mutex_init_generic(struct mutex *lock)
+{
+ __mutex_init_generic(lock);
+}
+EXPORT_SYMBOL(mutex_init_generic);
/*
* Optimistic trylock that only works in the uncontended case. Make sure to
@@ -166,7 +168,21 @@ static __always_inline bool __mutex_unlock_fast(struct mutex *lock)
return atomic_long_try_cmpxchg_release(&lock->owner, &curr, 0UL);
}
-#endif
+
+#else /* !CONFIG_DEBUG_LOCK_ALLOC */
+
+void mutex_init_lockep(struct mutex *lock, const char *name, struct lock_class_key *key)
+{
+ __mutex_init_generic(lock);
+
+ /*
+ * Make sure we are not reinitializing a held lock:
+ */
+ debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+ lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_SLEEP);
+}
+EXPORT_SYMBOL(mutex_init_lockep);
+#endif /* !CONFIG_DEBUG_LOCK_ALLOC */
static inline void __mutex_set_flag(struct mutex *lock, unsigned long flag)
{
diff --git a/kernel/locking/mutex.h b/kernel/locking/mutex.h
index 2e8080a9bee3..9ad4da8cea00 100644
--- a/kernel/locking/mutex.h
+++ b/kernel/locking/mutex.h
@@ -59,8 +59,7 @@ extern void debug_mutex_add_waiter(struct mutex *lock,
extern void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
struct task_struct *task);
extern void debug_mutex_unlock(struct mutex *lock);
-extern void debug_mutex_init(struct mutex *lock, const char *name,
- struct lock_class_key *key);
+extern void debug_mutex_init(struct mutex *lock);
#else /* CONFIG_DEBUG_MUTEXES */
# define debug_mutex_lock_common(lock, waiter) do { } while (0)
# define debug_mutex_wake_waiter(lock, waiter) do { } while (0)
@@ -68,6 +67,6 @@ extern void debug_mutex_init(struct mutex *lock, const char *name,
# define debug_mutex_add_waiter(lock, waiter, ti) do { } while (0)
# define debug_mutex_remove_waiter(lock, waiter, ti) do { } while (0)
# define debug_mutex_unlock(lock) do { } while (0)
-# define debug_mutex_init(lock, name, key) do { } while (0)
+# define debug_mutex_init(lock) do { } while (0)
#endif /* !CONFIG_DEBUG_MUTEXES */
#endif /* CONFIG_PREEMPT_RT */
diff --git a/kernel/locking/rtmutex_api.c b/kernel/locking/rtmutex_api.c
index bafd5af98eae..59dbd29cb219 100644
--- a/kernel/locking/rtmutex_api.c
+++ b/kernel/locking/rtmutex_api.c
@@ -515,13 +515,11 @@ void rt_mutex_debug_task_free(struct task_struct *task)
#ifdef CONFIG_PREEMPT_RT
/* Mutexes */
-void __mutex_rt_init(struct mutex *mutex, const char *name,
- struct lock_class_key *key)
+static void __mutex_rt_init_generic(struct mutex *mutex)
{
+ rt_mutex_base_init(&mutex->rtmutex);
debug_check_no_locks_freed((void *)mutex, sizeof(*mutex));
- lockdep_init_map_wait(&mutex->dep_map, name, key, 0, LD_WAIT_SLEEP);
}
-EXPORT_SYMBOL(__mutex_rt_init);
static __always_inline int __mutex_lock_common(struct mutex *lock,
unsigned int state,
@@ -542,6 +540,13 @@ static __always_inline int __mutex_lock_common(struct mutex *lock,
}
#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void mutex_rt_init_lockdep(struct mutex *mutex, const char *name, struct lock_class_key *key)
+{
+ __mutex_rt_init_generic(mutex);
+ lockdep_init_map_wait(&mutex->dep_map, name, key, 0, LD_WAIT_SLEEP);
+}
+EXPORT_SYMBOL(mutex_rt_init_lockdep);
+
void __sched mutex_lock_nested(struct mutex *lock, unsigned int subclass)
{
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass, NULL, _RET_IP_);
@@ -598,6 +603,12 @@ int __sched _mutex_trylock_nest_lock(struct mutex *lock,
EXPORT_SYMBOL_GPL(_mutex_trylock_nest_lock);
#else /* CONFIG_DEBUG_LOCK_ALLOC */
+void mutex_rt_init_generic(struct mutex *mutex)
+{
+ __mutex_rt_init_generic(mutex);
+}
+EXPORT_SYMBOL(mutex_rt_init_generic);
+
void __sched mutex_lock(struct mutex *lock)
{
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, NULL, _RET_IP_);