Messages in this thread | | | Date | Mon, 13 Jan 2020 15:55:42 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 1/6] locking/lockdep: Track number of zapped classes |
| |
On Mon, Dec 16, 2019 at 10:15:12AM -0500, Waiman Long wrote: > The whole point of the lockdep dynamic key patch is to allow unused > locks to be removed from the lockdep data buffers so that existing > buffer space can be reused. However, there is no way to find out how > many unused locks are zapped and so we don't know if the zapping process > is working properly. > > Add a new nr_zapped_classes variable to track that and show it in > /proc/lockdep_stats if it is non-zero. >
> diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c > index dadb7b7fba37..d98d349bb648 100644 > --- a/kernel/locking/lockdep_proc.c > +++ b/kernel/locking/lockdep_proc.c > @@ -336,6 +336,15 @@ static int lockdep_stats_show(struct seq_file *m, void *v) > seq_printf(m, " debug_locks: %11u\n", > debug_locks); > > + /* > + * Zappped classes and lockdep data buffers reuse statistics. > + */ > + if (!nr_zapped_classes) > + return 0; > + > + seq_puts(m, "\n"); > + seq_printf(m, " zapped classes: %11lu\n", > + nr_zapped_classes); > return 0; > }
Why is that conditional?
| |