[PATCH v4 06/22] perf: Redirect output from inherited events to parents

[Alexander Shishkin]

In order to collect AUX data from an inherited event, we can redirect its
output to parent's ring buffer if possible (they must be cpu affine). This
patch adds set_output() to the inheritance path.

Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
---
 kernel/events/core.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 67f857ab56..e36478564c 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7962,6 +7962,12 @@ inherit_event(struct perf_event *parent_event,
 		= parent_event->overflow_handler_context;
 
 	/*
+	 * Direct child's output to parent's ring buffer (if any)
+	 */
+	if (parent_event->cpu != -1)
+		(void)perf_event_set_output(child_event, parent_event);
+
+	/*
 	 * Precalculate sample_data sizes
 	 */
 	perf_event__header_size(child_event);
-- 
2.1.0

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