Merge branch 'next' into for-linus

Second round of updates for 3.20.

1 files changed, 8 insertions, 2 deletions

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index f7c65adaa428..557e128e4df0 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -116,8 +116,14 @@ int armpmu_event_set_period(struct perf_event *event)
                 ret = 1;
         }
 
-        if (left > (s64)armpmu->max_period)
-                left = armpmu->max_period;
+        /*
+         * Limit the maximum period to prevent the counter value
+         * from overtaking the one we are about to program. In
+         * effect we are reducing max_period to account for
+         * interrupt latency (and we are being very conservative).
+         */
+        if (left > (armpmu->max_period >> 1))
+                left = armpmu->max_period >> 1;
 
         local64_set(&hwc->prev_count, (u64)-left);