ftrace: new continue entry - separate out from trace_entry
Some tracers will need to work with more than one entry. In order to do this
the trace_entry structure was split into two fields. One for the start of
all entries, and one to continue an existing entry.
The trace_entry structure now has a "field" entry that consists of the previous
content of the trace_entry, and a "cont" entry that is just a string buffer
the size of the "field" entry.
Thanks to Andrew Morton for suggesting this idea.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index f69f867..6ddd6a6 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -61,13 +61,12 @@
};
/*
- * The trace entry - the most basic unit of tracing. This is what
+ * The trace field - the most basic unit of tracing. This is what
* is printed in the end as a single line in the trace output, such as:
*
* bash-15816 [01] 235.197585: idle_cpu <- irq_enter
*/
-struct trace_entry {
- char type;
+struct trace_field {
char cpu;
char flags;
char preempt_count;
@@ -83,6 +82,18 @@
};
};
+struct trace_field_cont {
+ char buf[sizeof(struct trace_field)];
+};
+
+struct trace_entry {
+ char type;
+ union {
+ struct trace_field field;
+ struct trace_field_cont cont;
+ };
+};
+
#define TRACE_ENTRY_SIZE sizeof(struct trace_entry)
/*