lockdep: Add statistics info for max bfs queue depth

Add BFS statistics to the existing lockdep stats.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1246201486-7308-10-git-send-email-tom.leiming@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 6358cf7..744da62 100644 (file)
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -929,7 +929,7 @@ static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
 
 unsigned long bfs_accessed[BITS_TO_LONGS(MAX_LOCKDEP_ENTRIES)];
 static struct circular_queue  lock_cq;
-
+unsigned int max_bfs_queue_depth;
 static int __bfs(struct lock_list *source_entry,
                        void *data,
                        int (*match)(struct lock_list *entry, void *data),
@@ -975,6 +975,7 @@ static int __bfs(struct lock_list *source_entry,
 
                list_for_each_entry(entry, head, entry) {
                        if (!lock_accessed(entry)) {
+                               unsigned int cq_depth;
                                mark_lock_accessed(entry, lock);
                                if (match(entry, data)) {
                                        *target_entry = entry;
@@ -986,6 +987,9 @@ static int __bfs(struct lock_list *source_entry,
                                        ret = -1;
                                        goto exit;
                                }
+                               cq_depth = __cq_get_elem_count(cq);
+                               if (max_bfs_queue_depth < cq_depth)
+                                       max_bfs_queue_depth = cq_depth;
                        }
                }
        }

diff --git a/kernel/lockdep_internals.h b/kernel/lockdep_internals.h
index b115aaa..6baa880 100644 (file)
--- a/kernel/lockdep_internals.h
+++ b/kernel/lockdep_internals.h
@@ -138,6 +138,7 @@ extern atomic_t nr_find_usage_backwards_recursions;
 #endif
 
 
+extern unsigned int max_bfs_queue_depth;
 extern unsigned long nr_list_entries;
 extern struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
 extern unsigned long bfs_accessed[];
@@ -191,7 +192,7 @@ static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem)
        return 0;
 }
 
-static inline int __cq_get_elem_count(struct circular_queue *cq)
+static inline unsigned int  __cq_get_elem_count(struct circular_queue *cq)
 {
        return (cq->rear - cq->front)&(MAX_CIRCULAR_QUE_SIZE-1);
 }

diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c
index d7135aa..9a1bf34 100644 (file)
--- a/kernel/lockdep_proc.c
+++ b/kernel/lockdep_proc.c
@@ -411,6 +411,8 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
                        max_lockdep_depth);
        seq_printf(m, " max recursion depth:           %11u\n",
                        max_recursion_depth);
+       seq_printf(m, " max bfs queue depth:           %11u\n",
+                       max_bfs_queue_depth);
        lockdep_stats_debug_show(m);
        seq_printf(m, " debug_locks:                   %11u\n",
                        debug_locks);