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-rw-r--r--kernel/trace/ring_buffer.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index af2f10d9f3f1..6f0b42ceeb00 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -510,6 +510,7 @@ struct ring_buffer_iter {
u64 read_stamp;
u64 page_stamp;
struct ring_buffer_event *event;
+ int missed_events;
};
/**
@@ -1988,6 +1989,7 @@ rb_iter_head_event(struct ring_buffer_iter *iter)
iter->page_stamp = iter->read_stamp = iter->head_page->page->time_stamp;
iter->head = 0;
iter->next_event = 0;
+ iter->missed_events = 1;
return NULL;
}
@@ -4191,6 +4193,20 @@ ring_buffer_peek(struct trace_buffer *buffer, int cpu, u64 *ts,
return event;
}
+/** ring_buffer_iter_dropped - report if there are dropped events
+ * @iter: The ring buffer iterator
+ *
+ * Returns true if there was dropped events since the last peek.
+ */
+bool ring_buffer_iter_dropped(struct ring_buffer_iter *iter)
+{
+ bool ret = iter->missed_events != 0;
+
+ iter->missed_events = 0;
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_iter_dropped);
+
/**
* ring_buffer_iter_peek - peek at the next event to be read
* @iter: The ring buffer iterator