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-rw-r--r--kernel/trace/ring_buffer.c22
1 files changed, 7 insertions, 15 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 6f0b42ceeb00..448d5f528764 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -4034,7 +4034,6 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
struct ring_buffer_per_cpu *cpu_buffer;
struct ring_buffer_event *event;
int nr_loops = 0;
- bool failed = false;
if (ts)
*ts = 0;
@@ -4056,19 +4055,14 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
return NULL;
/*
- * We repeat when a time extend is encountered or we hit
- * the end of the page. Since the time extend is always attached
- * to a data event, we should never loop more than three times.
- * Once for going to next page, once on time extend, and
- * finally once to get the event.
- * We should never hit the following condition more than thrice,
- * unless the buffer is very small, and there's a writer
- * that is causing the reader to fail getting an event.
+ * As the writer can mess with what the iterator is trying
+ * to read, just give up if we fail to get an event after
+ * three tries. The iterator is not as reliable when reading
+ * the ring buffer with an active write as the consumer is.
+ * Do not warn if the three failures is reached.
*/
- if (++nr_loops > 3) {
- RB_WARN_ON(cpu_buffer, !failed);
+ if (++nr_loops > 3)
return NULL;
- }
if (rb_per_cpu_empty(cpu_buffer))
return NULL;
@@ -4079,10 +4073,8 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
}
event = rb_iter_head_event(iter);
- if (!event) {
- failed = true;
+ if (!event)
goto again;
- }
switch (event->type_len) {
case RINGBUF_TYPE_PADDING: