perfcounters: use hw_event.disable flag

Impact: implement default-off counters

Make sure that counters that are created with counter.hw_event.disabled=1,
get created in disabled state.

They can be enabled via:

        prctl(PR_TASK_PERF_COUNTERS_ENABLE);

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 0 deletions

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 16396e9406fa..5431e790b5d6 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -1093,6 +1093,9 @@ perf_counter_alloc(struct perf_counter_hw_event *hw_event,
         counter->group_leader           = group_leader;
         counter->hw_ops                 = NULL;
 
+        if (hw_event->disabled)
+                counter->state = PERF_COUNTER_STATE_OFF;
+
         hw_ops = NULL;
         if (!hw_event->raw && hw_event->type < 0)
                 hw_ops = sw_perf_counter_init(counter);