diff options
| author | Boqun Feng <boqun.feng@gmail.com> | 2020-08-07 15:42:24 +0800 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-08-26 12:42:04 +0200 |
| commit | bd76eca10de2eb9998d5125b08e8997cbf5508d5 (patch) | |
| tree | 0e44eb90aba2709830cef110dbaceaaf89acaeb2 | |
| parent | d563bc6ead9e79be37067d58509a605b67378184 (diff) | |
| download | linux-bd76eca10de2eb9998d5125b08e8997cbf5508d5.tar.bz2 | |
lockdep: Reduce the size of lock_list::distance
lock_list::distance is always not greater than MAX_LOCK_DEPTH (which
is 48 right now), so a u16 will fit. This patch reduces the size of
lock_list::distance to save space, so that we can introduce other fields
to help detect recursive read lock deadlocks without increasing the size
of lock_list structure.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-6-boqun.feng@gmail.com
| -rw-r--r-- | include/linux/lockdep.h | 2 | ||||
| -rw-r--r-- | kernel/locking/lockdep.c | 6 |
2 files changed, 4 insertions, 4 deletions
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 7cae5ea00d59..22750102b5fe 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -54,7 +54,7 @@ struct lock_list { struct lock_class *class; struct lock_class *links_to; const struct lock_trace *trace; - int distance; + u16 distance; /* * The parent field is used to implement breadth-first search, and the diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 150686a71be0..668a983d6405 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -1320,7 +1320,7 @@ static struct lock_list *alloc_list_entry(void) */ static int add_lock_to_list(struct lock_class *this, struct lock_class *links_to, struct list_head *head, - unsigned long ip, int distance, + unsigned long ip, u16 distance, const struct lock_trace *trace) { struct lock_list *entry; @@ -2489,7 +2489,7 @@ check_deadlock(struct task_struct *curr, struct held_lock *next) */ static int check_prev_add(struct task_struct *curr, struct held_lock *prev, - struct held_lock *next, int distance, + struct held_lock *next, u16 distance, struct lock_trace **const trace) { struct lock_list *entry; @@ -2622,7 +2622,7 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) goto out_bug; for (;;) { - int distance = curr->lockdep_depth - depth + 1; + u16 distance = curr->lockdep_depth - depth + 1; hlock = curr->held_locks + depth - 1; /* |