lockstat: Fix min, max times in /proc/lock_stats

Fix min, max times in /proc/lock_stats

(1) When collecting lock hold and wait times, if the current minimum
    time is zero, it will be replaced by the next time.

(2) When aggregating minimum and maximum lock hold and wait times
    accross cpus, the values are added, instead of selecting the
    minimum and maximum.

Signed-off-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4B05BBAE.2050005@am.sony.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index f5dcd36d3151a0e3563f786f050795d605d25f99..7a3ae56b3a7f6625c7d248982a665a92bf66b174 100644 (file)
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -168,7 +168,7 @@ static void lock_time_inc(struct lock_time *lt, u64 time)
        if (time > lt->max)
                lt->max = time;
 
-       if (time < lt->min || !lt->min)
+       if (time < lt->min || !lt->nr)
                lt->min = time;
 
        lt->total += time;
@@ -177,8 +177,15 @@ static void lock_time_inc(struct lock_time *lt, u64 time)
 
 static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
 {
-       dst->min += src->min;
-       dst->max += src->max;
+       if (!src->nr)
+               return;
+
+       if (src->max > dst->max)
+               dst->max = src->max;
+
+       if (src->min < dst->min || !dst->nr)
+               dst->min = src->min;
+
        dst->total += src->total;
        dst->nr += src->nr;
 }