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tracing: make event directory structure

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This patch adds the directory /debug/tracing/events/ that will contain
all the registered trace points.

 # ls /debug/tracing/events/
sched_kthread_stop      sched_process_fork  sched_switch
sched_kthread_stop_ret  sched_process_free  sched_wait_task
sched_migrate_task      sched_process_wait  sched_wakeup
sched_process_exit      sched_signal_send   sched_wakeup_new

 # ls /debug/tracing/events/sched_switch/
enable

 # cat /debug/tracing/events/sched_switch/enable
1

 # cat /debug/tracing/set_event
sched_switch

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This commit is contained in:
Steven Rostedt 2009-02-24 14:15:08 -05:00
parent f3fe8e4a38
commit 1473e4417c
2 changed files with 137 additions and 7 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

137
kernel/trace/trace_events.c
View file

@ -12,6 +12,11 @@
#include "trace_events.h"
#define events_for_each(event) \
for (event = __start_ftrace_events; \
(unsigned long)event < (unsigned long)__stop_ftrace_events; \
event++)
void event_trace_printk(unsigned long ip, const char *fmt, ...)
{
va_list ap;
@ -39,15 +44,16 @@ static void ftrace_clear_events(void)
static int ftrace_set_clr_event(char *buf, int set)
{
struct ftrace_event_call *call = (void *)__start_ftrace_events;
struct ftrace_event_call *call = __start_ftrace_events;
while ((unsigned long)call < (unsigned long)__stop_ftrace_events) {
events_for_each(call) {
if (strcmp(buf, call->name) != 0) {
call++;
if (!call->name)
continue;
if (strcmp(buf, call->name) != 0)
continue;
}
if (set) {
/* Already set? */
@ -223,6 +229,67 @@ ftrace_event_seq_open(struct inode *inode, struct file *file)
return ret;
}
static ssize_t
event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct ftrace_event_call *call = filp->private_data;
char *buf;
if (call->enabled)
buf = "1\n";
else
buf = "0\n";
return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
}
static ssize_t
event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct ftrace_event_call *call = filp->private_data;
char buf[64];
unsigned long val;
int ret;
if (cnt >= sizeof(buf))
return -EINVAL;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
ret = strict_strtoul(buf, 10, &val);
if (ret < 0)
return ret;
switch (val) {
case 0:
if (!call->enabled)
break;
call->enabled = 0;
call->unregfunc();
break;
case 1:
if (call->enabled)
break;
call->enabled = 1;
call->regfunc();
break;
default:
return -EINVAL;
}
*ppos += cnt;
return cnt;
}
static const struct seq_operations show_event_seq_ops = {
.start = t_start,
.next = t_next,
@ -252,10 +319,59 @@ static const struct file_operations ftrace_set_event_fops = {
.release = seq_release,
};
static const struct file_operations ftrace_enable_fops = {
.open = tracing_open_generic,
.read = event_enable_read,
.write = event_enable_write,
};
static struct dentry *event_trace_events_dir(void)
{
static struct dentry *d_tracer;
static struct dentry *d_events;
if (d_events)
return d_events;
d_tracer = tracing_init_dentry();
if (!d_tracer)
return NULL;
d_events = debugfs_create_dir("events", d_tracer);
if (!d_events)
pr_warning("Could not create debugfs "
"'events' directory\n");
return d_events;
}
static int
event_create_dir(struct ftrace_event_call *call, struct dentry *d_events)
{
struct dentry *entry;
call->dir = debugfs_create_dir(call->name, d_events);
if (!call->dir) {
pr_warning("Could not create debugfs "
"'%s' directory\n", call->name);
return -1;
}
entry = debugfs_create_file("enable", 0644, call->dir, call,
&ftrace_enable_fops);
if (!entry)
pr_warning("Could not create debugfs "
"'%s/enable' entry\n", call->name);
return 0;
}
static __init int event_trace_init(void)
{
struct ftrace_event_call *call = __start_ftrace_events;
struct dentry *d_tracer;
struct dentry *entry;
struct dentry *d_events;
d_tracer = tracing_init_dentry();
if (!d_tracer)
@ -275,6 +391,17 @@ static __init int event_trace_init(void)
pr_warning("Could not create debugfs "
"'set_event' entry\n");
d_events = event_trace_events_dir();
if (!d_events)
return 0;
events_for_each(call) {
/* The linker may leave blanks */
if (!call->name)
continue;
event_create_dir(call, d_events);
}
return 0;
}
fs_initcall(event_trace_init);

7
kernel/trace/trace_events.h
View file

@ -1,11 +1,13 @@
#ifndef _LINUX_KERNEL_TRACE_EVENTS_H
#define _LINUX_KERNEL_TRACE_EVENTS_H
#include <linux/debugfs.h>
#include <linux/ftrace.h>
#include "trace.h"
struct ftrace_event_call {
char *name;
struct dentry *dir;
int enabled;
int (*regfunc)(void);
void (*unregfunc)(void);
@ -39,6 +41,7 @@ static void ftrace_unreg_event_##call(void) \
} \
\
static struct ftrace_event_call __used \
__attribute__((__aligned__(4))) \
__attribute__((section("_ftrace_events"))) event_##call = { \
.name = #call, \
.regfunc = ftrace_reg_event_##call, \
@ -46,7 +49,7 @@ __attribute__((section("_ftrace_events"))) event_##call = { \
}
void event_trace_printk(unsigned long ip, const char *fmt, ...);
extern unsigned long __start_ftrace_events[];
extern unsigned long __stop_ftrace_events[];
extern struct ftrace_event_call __start_ftrace_events[];
extern struct ftrace_event_call __stop_ftrace_events[];
#endif /* _LINUX_KERNEL_TRACE_EVENTS_H */