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lockdep: lockdep_set_notrack_class()

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Add a new helper to disable lockdep tracking entirely for a given class.

This is needed for bcachefs, which takes too many btree node locks for
lockdep to track. Instead, we have a single lockdep_map for "btree_trans
has any btree nodes locked", which makes more since given that we have
centralized lock management and a cycle detector.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2023-12-21 20:34:17 -05:00
parent 8f523d425e
commit 1a616c2fe9
4 changed files with 14 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/bcachefs/btree_locking.c
View File

@ -10,7 +10,7 @@ void bch2_btree_lock_init(struct btree_bkey_cached_common *b,
enum six_lock_init_flags flags) enum six_lock_init_flags flags)
{ {
__six_lock_init(&b->lock, "b->c.lock", &bch2_btree_node_lock_key, flags); __six_lock_init(&b->lock, "b->c.lock", &bch2_btree_node_lock_key, flags);
lockdep_set_novalidate_class(&b->lock); lockdep_set_notrack_class(&b->lock);
} }
#ifdef CONFIG_LOCKDEP #ifdef CONFIG_LOCKDEP

4
include/linux/lockdep.h
View File

@ -181,6 +181,9 @@ static inline void lockdep_init_map(struct lockdep_map *lock, const char *name,
#define lockdep_set_novalidate_class(lock) \ #define lockdep_set_novalidate_class(lock) \
lockdep_set_class_and_name(lock, &__lockdep_no_validate__, #lock) lockdep_set_class_and_name(lock, &__lockdep_no_validate__, #lock)
#define lockdep_set_notrack_class(lock) \
lockdep_set_class_and_name(lock, &__lockdep_no_track__, #lock)
/* /*
* Compare locking classes * Compare locking classes
*/ */
@ -338,6 +341,7 @@ static inline void lockdep_set_selftest_task(struct task_struct *task)
#define lockdep_set_subclass(lock, sub) do { } while (0) #define lockdep_set_subclass(lock, sub) do { } while (0)
#define lockdep_set_novalidate_class(lock) do { } while (0) #define lockdep_set_novalidate_class(lock) do { } while (0)
#define lockdep_set_notrack_class(lock) do { } while (0)
/* /*
* We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP

1
include/linux/lockdep_types.h
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@ -80,6 +80,7 @@ struct lock_class_key {
}; };
extern struct lock_class_key __lockdep_no_validate__; extern struct lock_class_key __lockdep_no_validate__;
extern struct lock_class_key __lockdep_no_track__;
struct lock_trace; struct lock_trace;

9
kernel/locking/lockdep.c
View File

@ -4918,6 +4918,9 @@ EXPORT_SYMBOL_GPL(lockdep_init_map_type);
struct lock_class_key __lockdep_no_validate__; struct lock_class_key __lockdep_no_validate__;
EXPORT_SYMBOL_GPL(__lockdep_no_validate__); EXPORT_SYMBOL_GPL(__lockdep_no_validate__);
struct lock_class_key __lockdep_no_track__;
EXPORT_SYMBOL_GPL(__lockdep_no_track__);
#ifdef CONFIG_PROVE_LOCKING #ifdef CONFIG_PROVE_LOCKING
void lockdep_set_lock_cmp_fn(struct lockdep_map *lock, lock_cmp_fn cmp_fn, void lockdep_set_lock_cmp_fn(struct lockdep_map *lock, lock_cmp_fn cmp_fn,
lock_print_fn print_fn) lock_print_fn print_fn)
@ -5002,6 +5005,9 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
if (unlikely(!debug_locks)) if (unlikely(!debug_locks))
return 0; return 0;
if (unlikely(lock->key == &__lockdep_no_track__))
return 0;
if (!prove_locking || lock->key == &__lockdep_no_validate__) if (!prove_locking || lock->key == &__lockdep_no_validate__)
check = 0; check = 0;
@ -5764,7 +5770,8 @@ void lock_release(struct lockdep_map *lock, unsigned long ip)
trace_lock_release(lock, ip); trace_lock_release(lock, ip);
if (unlikely(!lockdep_enabled())) if (unlikely(!lockdep_enabled() ||
lock->key == &__lockdep_no_track__))
return; return;
raw_local_irq_save(flags); raw_local_irq_save(flags);