lockstat: measure lock bouncing

[firefly-linux-kernel-4.4.55.git] / kernel / lockdep.c

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index cb64022851c87fb900c5ef7e908bd3278f1c44ab..156fce4960c31918f7324e3773a3b534b118d2ec 100644 (file)
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -177,6 +177,9 @@ struct lock_class_stats lock_stats(struct lock_class *class)
 
                lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
                lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
+
+               for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
+                       stats.bounces[i] += pcs->bounces[i];
        }
 
        return stats;
@@ -2325,6 +2328,9 @@ void lockdep_init_map(struct lockdep_map *lock, const char *name,
        lock->name = name;
        lock->key = key;
        lock->class_cache = NULL;
+#ifdef CONFIG_LOCK_STAT
+       lock->cpu = raw_smp_processor_id();
+#endif
        if (subclass)
                register_lock_class(lock, subclass, 1);
 }
@@ -2775,6 +2781,8 @@ found_it:
        stats = get_lock_stats(hlock->class);
        if (point < ARRAY_SIZE(stats->contention_point))
                stats->contention_point[i]++;
+       if (lock->cpu != smp_processor_id())
+               stats->bounces[bounce_contended + !!hlock->read]++;
        put_lock_stats(stats);
 }
 
@@ -2786,8 +2794,8 @@ __lock_acquired(struct lockdep_map *lock)
        struct lock_class_stats *stats;
        unsigned int depth;
        u64 now;
-       s64 waittime;
-       int i;
+       s64 waittime = 0;
+       int i, cpu;
 
        depth = curr->lockdep_depth;
        if (DEBUG_LOCKS_WARN_ON(!depth))
@@ -2809,19 +2817,25 @@ __lock_acquired(struct lockdep_map *lock)
        return;
 
 found_it:
-       if (!hlock->waittime_stamp)
-               return;
-
-       now = sched_clock();
-       waittime = now - hlock->waittime_stamp;
-       hlock->holdtime_stamp = now;
+       cpu = smp_processor_id();
+       if (hlock->waittime_stamp) {
+               now = sched_clock();
+               waittime = now - hlock->waittime_stamp;
+               hlock->holdtime_stamp = now;
+       }
 
        stats = get_lock_stats(hlock->class);
-       if (hlock->read)
-               lock_time_inc(&stats->read_waittime, waittime);
-       else
-               lock_time_inc(&stats->write_waittime, waittime);
+       if (waittime) {
+               if (hlock->read)
+                       lock_time_inc(&stats->read_waittime, waittime);
+               else
+                       lock_time_inc(&stats->write_waittime, waittime);
+       }
+       if (lock->cpu != cpu)
+               stats->bounces[bounce_acquired + !!hlock->read]++;
        put_lock_stats(stats);
+
+       lock->cpu = cpu;
 }
 
 void lock_contended(struct lockdep_map *lock, unsigned long ip)