[PATCH v6 5/6] locking/lockdep: Track number of zapped lock chains

[Waiman Long]

Add a new counter nr_zapped_lock_chains to track the number lock chains
that have been removed.

Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
---
 kernel/locking/lockdep.c           | 2 ++
 kernel/locking/lockdep_internals.h | 1 +
 kernel/locking/lockdep_proc.c      | 4 ++++
 3 files changed, 7 insertions(+)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index ef2a6432dd10..a63976c75253 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2626,6 +2626,7 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next)
 struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
 static DECLARE_BITMAP(lock_chains_in_use, MAX_LOCKDEP_CHAINS);
 static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
+unsigned long nr_zapped_lock_chains;
 unsigned int nr_chain_hlocks;
 
 struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
@@ -4797,6 +4798,7 @@ static void remove_class_from_lock_chain(struct pending_free *pf,
 	 */
 	hlist_del_rcu(&chain->entry);
 	__set_bit(chain - lock_chains, pf->lock_chains_being_freed);
+	nr_zapped_lock_chains++;
 #endif
 }
 
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index 926bfa4b4564..af722ceeda33 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -131,6 +131,7 @@ struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i);
 
 extern unsigned long nr_lock_classes;
 extern unsigned long nr_zapped_classes;
+extern unsigned long nr_zapped_lock_chains;
 extern unsigned long nr_list_entries;
 long lockdep_next_lockchain(long i);
 unsigned long lock_chain_count(void);
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
index ca735cb83f48..92fe0742453c 100644
--- a/kernel/locking/lockdep_proc.c
+++ b/kernel/locking/lockdep_proc.c
@@ -349,6 +349,10 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
 	seq_puts(m, "\n");
 	seq_printf(m, " zapped classes:                %11lu\n",
 			nr_zapped_classes);
+#ifdef CONFIG_PROVE_LOCKING
+	seq_printf(m, " zapped lock chains:            %11lu\n",
+			nr_zapped_lock_chains);
+#endif
 	return 0;
 }
 
-- 
2.18.1