tracing: Add needs_rec flag to event triggers (a5863dae) · Commits · 戴 / test

Add a new needs_rec flag for triggers that require unconditional access to trace records in order to function. Normally a trigger requires access to the contents of a trace record only if it has a filter associated with it (since filters need the contents of a record in order to make a filtering decision). Some types of triggers, such as 'hist' triggers, require access to trace record contents independent of the presence of filters, so add a new flag for those triggers. Link: http://lkml.kernel.org/r/7be8fa38f9b90fdb6c47ca0f98d20a07b9fd512b.1449767187.git.tom.zanussi@linux.intel.com Signed-off-by:

Tom Zanussi <tom.zanussi@linux.intel.com> Tested-by:

Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by:

Namhyung Kim <namhyung@kernel.org> Signed-off-by:

Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -1292,6 +1292,12 @@ struct event_trigger_ops {
		* itself logs to the trace buffer, this flag should be set,
		* otherwise it can be left unspecified.
		*
		* @needs_rec: A flag that says whether or not this command needs
		* access to the trace record in order to perform its function,
		* regardless of whether or not it has a filter associated with
		* it (filters make a trigger require access to the trace record
		* but are not always present).
		*
		* All the methods below, except for @set_filter(), must be
		* implemented.
		*
		@@ -1332,6 +1338,7 @@ struct event_command {
		char *name;
		enum event_trigger_type trigger_type;
		bool post_trigger;
		bool needs_rec;
		int (func)(struct event_command cmd_ops,
		struct trace_event_file *file,
		char glob, char cmd, char *params);

kernel/trace/trace_events_trigger.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -493,7 +493,8 @@ void update_cond_flag(struct trace_event_file *file)
		bool set_cond = false;

		list_for_each_entry_rcu(data, &file->triggers, list) {
		if (data->filter \|\| data->cmd_ops->post_trigger) {
		if (data->filter \|\| data->cmd_ops->post_trigger \|\|
		data->cmd_ops->needs_rec) {
		set_cond = true;
		break;
		}

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