Add 'traceon' and 'traceoff' ftrace_func_command commands. traceon
and traceoff event triggers are added by the user via these commands
in a similar way and using practically the same syntax as the
analagous 'traceon' and 'traceoff' ftrace function commands, but
instead of writing to the set_ftrace_filter file, the traceon and
traceoff triggers are written to the per-event 'trigger' files:
echo 'traceon' > .../tracing/events/somesys/someevent/trigger
echo 'traceoff' > .../tracing/events/somesys/someevent/trigger
The above command will turn tracing on or off whenever someevent is
hit.
This also adds a 'count' version that limits the number of times the
command will be invoked:
echo 'traceon:N' > .../tracing/events/somesys/someevent/trigger
echo 'traceoff:N' > .../tracing/events/somesys/someevent/trigger
Where N is the number of times the command will be invoked.
The above commands will will turn tracing on or off whenever someevent
is hit, but only N times.
Signed-off-by: Tom Zanussi <tom.zanu...@linux.intel.com>
---
include/linux/ftrace_event.h | 1 +
kernel/trace/trace_events_trigger.c | 182 ++++++++++++++++++++++++++++++++++++
2 files changed, 183 insertions(+)
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 0765d3d..4c8f7c1 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -318,6 +318,7 @@ struct ftrace_event_file {
enum trigger_mode {
TM_NONE = (0),
+ TM_TRACE_ONOFF = (1 << 0),
};
extern void destroy_preds(struct ftrace_event_call *call);
diff --git a/kernel/trace/trace_events_trigger.c
b/kernel/trace/trace_events_trigger.c
index 7a52109..d5a10ed 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -564,7 +564,189 @@ event_trigger_callback(struct event_command *cmd_ops,
goto out;
}
+static void
+traceon_trigger(void **_data)
+{
+ struct event_trigger_data **p = (struct event_trigger_data **)_data;
+ struct event_trigger_data *data = *p;
+
+ if (!data)
+ return;
+
+ if (tracing_is_on())
+ return;
+
+ tracing_on();
+}
+
+static void
+traceon_count_trigger(void **_data)
+{
+ struct event_trigger_data **p = (struct event_trigger_data **)_data;
+ struct event_trigger_data *data = *p;
+
+ if (!data)
+ return;
+
+ if (!data->count)
+ return;
+
+ if (data->count != -1)
+ (data->count)--;
+
+ traceon_trigger(_data);
+}
+
+static void
+traceoff_trigger(void **_data)
+{
+ struct event_trigger_data **p = (struct event_trigger_data **)_data;
+ struct event_trigger_data *data = *p;
+
+ if (!data)
+ return;
+
+ if (!tracing_is_on())
+ return;
+
+ tracing_off();
+}
+
+static void
+traceoff_count_trigger(void **_data)
+{
+ struct event_trigger_data **p = (struct event_trigger_data **)_data;
+ struct event_trigger_data *data = *p;
+
+ if (!data)
+ return;
+
+ if (!data->count)
+ return;
+
+ if (data->count != -1)
+ (data->count)--;
+
+ traceoff_trigger(_data);
+}
+
+static int
+traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
+ void *_data)
+{
+ struct event_trigger_data *data = _data;
+
+ return event_trigger_print("traceon", m, (void *)data->count,
+ data->filter_str);
+}
+
+static int
+traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
+ void *_data)
+{
+ struct event_trigger_data *data = _data;
+
+ return event_trigger_print("traceoff", m, (void *)data->count,
+ data->filter_str);
+}
+
+static struct event_trigger_ops traceon_trigger_ops = {
+ .func = traceon_trigger,
+ .print = traceon_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
+};
+
+static struct event_trigger_ops traceon_count_trigger_ops = {
+ .func = traceon_count_trigger,
+ .print = traceon_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
+};
+
+static struct event_trigger_ops traceoff_trigger_ops = {
+ .func = traceoff_trigger,
+ .print = traceoff_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
+};
+
+static struct event_trigger_ops traceoff_count_trigger_ops = {
+ .func = traceoff_count_trigger,
+ .print = traceoff_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
+};
+
+static struct event_trigger_ops *
+onoff_get_trigger_ops(char *cmd, char *param)
+{
+ struct event_trigger_ops *ops;
+
+ /* we register both traceon and traceoff to this callback */
+ if (strcmp(cmd, "traceon") == 0)
+ ops = param ? &traceon_count_trigger_ops :
+ &traceon_trigger_ops;
+ else
+ ops = param ? &traceoff_count_trigger_ops :
+ &traceoff_trigger_ops;
+
+ return ops;
+}
+
+static struct event_command trigger_traceon_cmd = {
+ .name = "traceon",
+ .trigger_mode = TM_TRACE_ONOFF,
+ .func = event_trigger_callback,
+ .reg = register_trigger,
+ .unreg = unregister_trigger,
+ .get_trigger_ops = onoff_get_trigger_ops,
+};
+
+static struct event_command trigger_traceoff_cmd = {
+ .name = "traceoff",
+ .trigger_mode = TM_TRACE_ONOFF,
+ .func = event_trigger_callback,
+ .reg = register_trigger,
+ .unreg = unregister_trigger,
+ .get_trigger_ops = onoff_get_trigger_ops,
+};
+
+static __init void unregister_trigger_traceon_traceoff_cmds(void)
+{
+ unregister_event_command(&trigger_traceon_cmd,
+ &trigger_commands,
+ &trigger_cmd_mutex);
+ unregister_event_command(&trigger_traceoff_cmd,
+ &trigger_commands,
+ &trigger_cmd_mutex);
+}
+
+static __init int register_trigger_traceon_traceoff_cmds(void)
+{
+ int ret;
+
+ ret = register_event_command(&trigger_traceon_cmd, &trigger_commands,
+ &trigger_cmd_mutex);
+ if (WARN_ON(ret < 0))
+ return ret;
+ ret = register_event_command(&trigger_traceoff_cmd, &trigger_commands,
+ &trigger_cmd_mutex);
+ if (WARN_ON(ret < 0))
+ unregister_trigger_traceon_traceoff_cmds();
+
+ return ret;
+}
+
__init int register_trigger_cmds(void)
{
+ int ret;
+
+ ret = register_trigger_traceon_traceoff_cmds();
+ if (ret) {
+ unregister_trigger_traceon_traceoff_cmds();
+ return ret;
+ }
+
return 0;
}
--
1.7.11.4
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