Duh the retry setup if the number overflows is not correct.
Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
---
lib/percpu_counter.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
Index: linux-2.6/lib/percpu_counter.c
===================================================================
--- linux-2.6.orig/lib/percpu_counter.c 2011-04-13 11:43:23.000000000 -0500
+++ linux-2.6/lib/percpu_counter.c 2011-04-13 11:43:30.000000000 -0500
@@ -80,9 +80,14 @@ void __percpu_counter_add(struct percpu_
/* In case of overflow fold it into the global counter instead */
if (new >= batch || new <= -batch) {
spin_lock(&fbc->lock);
- fbc->count += __this_cpu_read(*fbc->counters) + amount;
+ count = __this_cpu_read(*fbc->counters);
+ fbc->count += count + amount;
spin_unlock(&fbc->lock);
- amount = 0;
+ /*
+ * If cmpxchg fails then we need to subtract the amount that
+ * we found in the percpu value.
+ */
+ amount = -count;
new = 0;
}
--
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