1
linux/samples/trace_events/trace_custom_sched.c
Steven Rostedt (Google) 3a73333fb3 tracing: Add TRACE_CUSTOM_EVENT() macro
To make it really easy to add custom events from modules, add a
TRACE_CUSTOM_EVENT() macro that acts just like the TRACE_EVENT() macro,
but creates a custom event to an already existing tracepoint.

The trace_custom_sched.[ch] has been updated to use this new macro to show
how simple it is.

Link: https://lkml.kernel.org/r/20220303220625.738622494@goodmis.org

Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-03-11 11:49:24 -05:00

61 lines
1.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* event tracer
*
* Copyright (C) 2022 Google Inc, Steven Rostedt <rostedt@goodmis.org>
*/
#define pr_fmt(fmt) fmt
#include <linux/trace_events.h>
#include <linux/version.h>
#include <linux/module.h>
#include <linux/sched.h>
/*
* Must include the event header that the custom event will attach to,
* from the C file, and not in the custom header file.
*/
#include <trace/events/sched.h>
/* Declare CREATE_CUSTOM_TRACE_EVENTS before including custom header */
#define CREATE_CUSTOM_TRACE_EVENTS
#include "trace_custom_sched.h"
/*
* As the trace events are not exported to modules, the use of
* for_each_kernel_tracepoint() is needed to find the trace event
* to attach to. The fct() function below, is a callback that
* will be called for every event.
*
* Helper functions are created by the TRACE_CUSTOM_EVENT() macro
* update the event. Those are of the form:
*
* trace_custom_event_<event>_update()
*
* Where <event> is the event to attach.
*/
static void fct(struct tracepoint *tp, void *priv)
{
trace_custom_event_sched_switch_update(tp);
trace_custom_event_sched_waking_update(tp);
}
static int __init trace_sched_init(void)
{
for_each_kernel_tracepoint(fct, NULL);
return 0;
}
static void __exit trace_sched_exit(void)
{
}
module_init(trace_sched_init);
module_exit(trace_sched_exit);
MODULE_AUTHOR("Steven Rostedt");
MODULE_DESCRIPTION("Custom scheduling events");
MODULE_LICENSE("GPL");