tracing: Add a per-event-trigger 'paused' field

Add a simple per-trigger 'paused' flag, allowing individual triggers
to pause.  We could leave it to individual triggers that need this
functionality to do it themselves, but we also want to allow other
events to control pausing, so add it to the trigger data.

Link: http://lkml.kernel.org/r/fed37e4879684d7dcc57fe00ce0cbf170032b06d.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>

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 0044b91..f186867 100644 (file)
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1172,6 +1172,7 @@ struct event_trigger_data {
        struct event_filter __rcu       *filter;
        char                            *filter_str;
        void                            *private_data;
+       bool                            paused;
        struct list_head                list;
 };
 

diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 0a62887..e4d8b37 100644 (file)
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -72,6 +72,8 @@ event_triggers_call(struct trace_event_file *file, void *rec)
                return tt;
 
        list_for_each_entry_rcu(data, &file->triggers, list) {
+               if (data->paused)
+                       continue;
                if (!rec) {
                        data->ops->func(data, rec);
                        continue;
@@ -110,6 +112,8 @@ event_triggers_post_call(struct trace_event_file *file,
        struct event_trigger_data *data;
 
        list_for_each_entry_rcu(data, &file->triggers, list) {
+               if (data->paused)
+                       continue;
                if (data->cmd_ops->trigger_type & tt)
                        data->ops->func(data, rec);
        }