Commit 4a089752 authored by Mathieu Desnoyers's avatar Mathieu Desnoyers Committed by Ingo Molnar

tracing: tracepoints, samples

Tracepoint example code under samples/.
Signed-off-by: 's avatarMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: 's avatar'Peter Zijlstra' <peterz@infradead.org>
Signed-off-by: 's avatarIngo Molnar <mingo@elte.hu>
parent 24b8d831
......@@ -13,6 +13,12 @@ config SAMPLE_MARKERS
help
This build markers example modules.
config SAMPLE_TRACEPOINTS
tristate "Build tracepoints examples -- loadable modules only"
depends on TRACEPOINTS && m
help
This build tracepoints example modules.
config SAMPLE_KOBJECT
tristate "Build kobject examples"
help
......
# Makefile for Linux samples code
obj-$(CONFIG_SAMPLES) += markers/ kobject/ kprobes/
obj-$(CONFIG_SAMPLES) += markers/ kobject/ kprobes/ tracepoints/
# builds the tracepoint example kernel modules;
# then to use one (as root): insmod <module_name.ko>
obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-sample.o
obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-probe-sample.o
obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-probe-sample2.o
#ifndef _TP_SAMPLES_TRACE_H
#define _TP_SAMPLES_TRACE_H
#include <linux/proc_fs.h> /* for struct inode and struct file */
#include <linux/tracepoint.h>
DEFINE_TRACE(subsys_event,
TPPROTO(struct inode *inode, struct file *file),
TPARGS(inode, file));
DEFINE_TRACE(subsys_eventb,
TPPROTO(void),
TPARGS());
#endif
/*
* tracepoint-probe-sample.c
*
* sample tracepoint probes.
*/
#include <linux/module.h>
#include <linux/file.h>
#include <linux/dcache.h>
#include "tp-samples-trace.h"
/*
* Here the caller only guarantees locking for struct file and struct inode.
* Locking must therefore be done in the probe to use the dentry.
*/
static void probe_subsys_event(struct inode *inode, struct file *file)
{
path_get(&file->f_path);
dget(file->f_path.dentry);
printk(KERN_INFO "Event is encountered with filename %s\n",
file->f_path.dentry->d_name.name);
dput(file->f_path.dentry);
path_put(&file->f_path);
}
static void probe_subsys_eventb(void)
{
printk(KERN_INFO "Event B is encountered\n");
}
int __init tp_sample_trace_init(void)
{
int ret;
ret = register_trace_subsys_event(probe_subsys_event);
WARN_ON(ret);
ret = register_trace_subsys_eventb(probe_subsys_eventb);
WARN_ON(ret);
return 0;
}
module_init(tp_sample_trace_init);
void __exit tp_sample_trace_exit(void)
{
unregister_trace_subsys_eventb(probe_subsys_eventb);
unregister_trace_subsys_event(probe_subsys_event);
}
module_exit(tp_sample_trace_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Tracepoint Probes Samples");
/*
* tracepoint-probe-sample2.c
*
* 2nd sample tracepoint probes.
*/
#include <linux/module.h>
#include <linux/fs.h>
#include "tp-samples-trace.h"
/*
* Here the caller only guarantees locking for struct file and struct inode.
* Locking must therefore be done in the probe to use the dentry.
*/
static void probe_subsys_event(struct inode *inode, struct file *file)
{
printk(KERN_INFO "Event is encountered with inode number %lu\n",
inode->i_ino);
}
int __init tp_sample_trace_init(void)
{
int ret;
ret = register_trace_subsys_event(probe_subsys_event);
WARN_ON(ret);
return 0;
}
module_init(tp_sample_trace_init);
void __exit tp_sample_trace_exit(void)
{
unregister_trace_subsys_event(probe_subsys_event);
}
module_exit(tp_sample_trace_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Tracepoint Probes Samples");
/* tracepoint-sample.c
*
* Executes a tracepoint when /proc/tracepoint-example is opened.
*
* (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
*
* This file is released under the GPLv2.
* See the file COPYING for more details.
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/proc_fs.h>
#include "tp-samples-trace.h"
struct proc_dir_entry *pentry_example;
static int my_open(struct inode *inode, struct file *file)
{
int i;
trace_subsys_event(inode, file);
for (i = 0; i < 10; i++)
trace_subsys_eventb();
return -EPERM;
}
static struct file_operations mark_ops = {
.open = my_open,
};
static int example_init(void)
{
printk(KERN_ALERT "example init\n");
pentry_example = proc_create("tracepoint-example", 0444, NULL,
&mark_ops);
if (!pentry_example)
return -EPERM;
return 0;
}
static void example_exit(void)
{
printk(KERN_ALERT "example exit\n");
remove_proc_entry("tracepoint-example", NULL);
}
module_init(example_init)
module_exit(example_exit)
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Tracepoint example");
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