summary refs log tree commit diff
path: root/kernel/trace/trace.h
diff options
context:
space:
mode:
authorSteven Rostedt (VMware) <rostedt@goodmis.org>2018-05-09 14:17:48 -0400
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2018-05-29 08:28:53 -0400
commit3dd8095368475a9538895ce757b63dd311e58fe8 (patch)
tree33d00f2039b91119b01fe7f46b403bf5360580df /kernel/trace/trace.h
parent5d948c86bb332cd143f4b2dc21d949baf38e29aa (diff)
downloadlinux-3dd8095368475a9538895ce757b63dd311e58fe8.tar.gz
tracing: Add trigger file for trace_markers tracefs/ftrace/print
Allow writing to the trace_markers file initiate triggers defined in
tracefs/ftrace/print/trigger file. This will allow of user space to trigger
the same type of triggers (including histograms) that the trace events use.

Had to create a ftrace_event_register() function that will become the
trace_marker print event's reg() function. This is required because of how
triggers are enabled:

  event_trigger_write() {
    event_trigger_regex_write() {
      trigger_process_regex() {
        for p in trigger_commands {
          p->func(); /* trigger_snapshot_cmd->func */
            event_trigger_callback() {
              cmd_ops->reg() /* register_trigger() */ {
                trace_event_trigger_enable_disable() {
                  trace_event_enable_disable() {
                    call->class->reg();

Without the reg() function, the trigger code will call a NULL pointer and
crash the system.

Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Karim Yaghmour <karim.yaghmour@opersys.com>
Cc: Brendan Gregg <bgregg@netflix.com>
Suggested-by: Joel Fernandes <joelaf@google.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace.h')
-rw-r--r--kernel/trace/trace.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index d0319cbacf11..630c5a24b2b2 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -259,6 +259,7 @@ struct trace_array {
 	struct trace_options	*topts;
 	struct list_head	systems;
 	struct list_head	events;
+	struct trace_event_file *trace_marker_file;
 	cpumask_var_t		tracing_cpumask; /* only trace on set CPUs */
 	int			ref;
 #ifdef CONFIG_FUNCTION_TRACER