locking/lockdep: Track number of zapped classes
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 counter to track that and show it in
/proc/lockdep_stats.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200206152408.24165-4-longman@redhat.com
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 35449f5..28222d0 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -147,6 +147,7 @@ static DECLARE_BITMAP(list_entries_in_use, MAX_LOCKDEP_ENTRIES);
#define KEYHASH_SIZE (1UL << KEYHASH_BITS)
static struct hlist_head lock_keys_hash[KEYHASH_SIZE];
unsigned long nr_lock_classes;
+unsigned long nr_zapped_classes;
#ifndef CONFIG_DEBUG_LOCKDEP
static
#endif
@@ -4880,6 +4881,7 @@ static void zap_class(struct pending_free *pf, struct lock_class *class)
}
remove_class_from_lock_chains(pf, class);
+ nr_zapped_classes++;
}
static void reinit_class(struct lock_class *class)
