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tracing: Add enable_hist/disable_hist triggers

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Similar to enable_event/disable_event triggers, these triggers enable
and disable the aggregation of events into maps rather than enabling
and disabling their writing into the trace buffer.

They can be used to automatically start and stop hist triggers based
on a matching filter condition.

If there's a paused hist trigger on system:event, the following would
start it when the filter condition was hit:

  # echo enable_hist:system:event [ if filter] > event/trigger

And the following would disable a running system:event hist trigger:

  # echo disable_hist:system:event [ if filter] > event/trigger

See Documentation/trace/events.txt for real examples.

Link: http://lkml.kernel.org/r/f812f086e52c8b7c8ad5443487375e03c96a601f.1457029949.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>
This commit is contained in:
Tom Zanussi
2016-03-03 12:54:55 -06:00
committed by Steven Rostedt
parent 6a475cb17f
commit d0bad49bb0
5 changed files with 196 additions and 31 deletions
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32
kernel/trace/trace.h
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@@ -1166,8 +1166,10 @@ extern const struct file_operations event_hist_fops;
#ifdef CONFIG_HIST_TRIGGERS
extern int register_trigger_hist_cmd(void);
extern int register_trigger_hist_enable_disable_cmds(void);
#else
static inline int register_trigger_hist_cmd(void) { return 0; }
static inline int register_trigger_hist_enable_disable_cmds(void) { return 0; }
#endif
extern int register_trigger_cmds(void);
@@ -1185,6 +1187,34 @@ struct event_trigger_data {
struct list_head list;
};
/* Avoid typos */
#define ENABLE_EVENT_STR "enable_event"
#define DISABLE_EVENT_STR "disable_event"
#define ENABLE_HIST_STR "enable_hist"
#define DISABLE_HIST_STR "disable_hist"
struct enable_trigger_data {
struct trace_event_file *file;
bool enable;
bool hist;
};
extern int event_enable_trigger_print(struct seq_file *m,
struct event_trigger_ops *ops,
struct event_trigger_data *data);
extern void event_enable_trigger_free(struct event_trigger_ops *ops,
struct event_trigger_data *data);
extern int event_enable_trigger_func(struct event_command *cmd_ops,
struct trace_event_file *file,
char *glob, char *cmd, char *param);
extern int event_enable_register_trigger(char *glob,
struct event_trigger_ops *ops,
struct event_trigger_data *data,
struct trace_event_file *file);
extern void event_enable_unregister_trigger(char *glob,
struct event_trigger_ops *ops,
struct event_trigger_data *test,
struct trace_event_file *file);
extern void trigger_data_free(struct event_trigger_data *data);
extern int event_trigger_init(struct event_trigger_ops *ops,
struct event_trigger_data *data);
@@ -1198,6 +1228,8 @@ extern int set_trigger_filter(char *filter_str,
struct event_trigger_data *trigger_data,
struct trace_event_file *file);
extern int register_event_command(struct event_command *cmd);
extern int unregister_event_command(struct event_command *cmd);
extern int register_trigger_hist_enable_disable_cmds(void);
/**
* struct event_trigger_ops - callbacks for trace event triggers