fb1b6d8b51
A no-op tracer which can serve two purposes:
1. A template for development of a new tracer.
2. A convenient way to see ftrace_printk() calls without
an irrelevant trace making the output messy.
[ mingo@elte.hu: resolved conflicts ]
Signed-off-by: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
66 lines
1.1 KiB
C
66 lines
1.1 KiB
C
/*
|
|
* nop tracer
|
|
*
|
|
* Copyright (C) 2008 Steven Noonan <steven@uplinklabs.net>
|
|
*
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/debugfs.h>
|
|
#include <linux/ftrace.h>
|
|
|
|
#include "trace.h"
|
|
|
|
static struct trace_array *ctx_trace;
|
|
|
|
static void start_nop_trace(struct trace_array *tr)
|
|
{
|
|
/* Nothing to do! */
|
|
}
|
|
|
|
static void stop_nop_trace(struct trace_array *tr)
|
|
{
|
|
/* Nothing to do! */
|
|
}
|
|
|
|
static void nop_trace_init(struct trace_array *tr)
|
|
{
|
|
ctx_trace = tr;
|
|
|
|
if (tr->ctrl)
|
|
start_nop_trace(tr);
|
|
}
|
|
|
|
static void nop_trace_reset(struct trace_array *tr)
|
|
{
|
|
if (tr->ctrl)
|
|
stop_nop_trace(tr);
|
|
}
|
|
|
|
static void nop_trace_ctrl_update(struct trace_array *tr)
|
|
{
|
|
/* When starting a new trace, reset the buffers */
|
|
if (tr->ctrl)
|
|
start_nop_trace(tr);
|
|
else
|
|
stop_nop_trace(tr);
|
|
}
|
|
|
|
static struct tracer nop_trace __read_mostly =
|
|
{
|
|
.name = "nop",
|
|
.init = nop_trace_init,
|
|
.reset = nop_trace_reset,
|
|
.ctrl_update = nop_trace_ctrl_update,
|
|
#ifdef CONFIG_FTRACE_SELFTEST
|
|
.selftest = trace_selftest_startup_nop,
|
|
#endif
|
|
};
|
|
|
|
__init static int init_nop_trace(void)
|
|
{
|
|
return register_tracer(&nop_trace);
|
|
}
|
|
device_initcall(init_nop_trace);
|