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

From: Waiman Long
Date: Thu Feb 06 2020 - 10:24:49 EST


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