[PATCH] lockstat - repair erronous contention statistics

From: Joe Korty
Date: Mon Aug 25 2008 - 17:49:35 EST


Fix bad contention counting in /proc/lock_stat.

/proc/lockstat tries to gather per-ip contention
statistics per-lock. This was failing due to
a garbage per-ip index selector being used.

Index: 2.6.26/kernel/lockdep.c
===================================================================
--- 2.6.26.orig/kernel/lockdep.c 2008-07-13 17:51:29.000000000 -0400
+++ 2.6.26/kernel/lockdep.c 2008-08-25 17:00:15.000000000 -0400
@@ -2791,7 +2791,7 @@

stats = get_lock_stats(hlock->class);
if (point < ARRAY_SIZE(stats->contention_point))
- stats->contention_point[i]++;
+ stats->contention_point[point]++;
if (lock->cpu != smp_processor_id())
stats->bounces[bounce_contended + !!hlock->read]++;
put_lock_stats(stats);
--
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