When calculating the delta, mask with MAX_PERIOD (24 bits) to handle
wrapping, which particularly happens with periodic sampling since the
value is intentionally set so that it will overflow soon.
Signed-off-by: James Hogan <james.ho...@imgtec.com>
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Arnaldo Carvalho de Melo <a...@ghostprotocols.net>
---
arch/metag/kernel/perf/perf_event.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/metag/kernel/perf/perf_event.c
b/arch/metag/kernel/perf/perf_event.c
index f38bf6d..8096db2 100644
--- a/arch/metag/kernel/perf/perf_event.c
+++ b/arch/metag/kernel/perf/perf_event.c
@@ -211,7 +211,7 @@ again:
/*
* Calculate the delta and add it to the counter.
*/
- delta = new_raw_count - prev_raw_count;
+ delta = (new_raw_count - prev_raw_count) & MAX_PERIOD;
local64_add(delta, &event->count);
}
--
1.8.1.2
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