tracing/ftrace: change the type of the print_line callback
We need a kind of disambiguation when a print_line callback
returns 0.
_There is not enough space to print all the entry.
Please flush the seq and retry.
_I can't handle this type of entry
This patch changes the type of this callback for better information.
Also some changes have been made in this V2.
_ Only relay to default functions after the print_line callback fails.
_ This patch doesn't fix the issue with the broken pipe (see patch 2/4 for that)
Some things are still in discussion:
_ Find better names for the enum print_line_t values
_ Change the type of print_trace_line into boolean.
Patches to change that can be sent later.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index e541a6b..a921ba5 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -177,6 +177,14 @@
struct trace_array_cpu *data[NR_CPUS];
};
+
+/* Return values for print_line callback */
+enum print_line_t {
+ TRACE_TYPE_PARTIAL_LINE = 0, /* Retry after flushing the seq */
+ TRACE_TYPE_HANDLED = 1,
+ TRACE_TYPE_UNHANDLED = 2 /* Relay to other output functions */
+};
+
/*
* A specific tracer, represented by methods that operate on a trace array:
*/
@@ -197,7 +205,7 @@
int (*selftest)(struct tracer *trace,
struct trace_array *tr);
#endif
- int (*print_line)(struct trace_iterator *iter);
+ enum print_line_t (*print_line)(struct trace_iterator *iter);
struct tracer *next;
int print_max;
};
