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trace: Move trace event enable from fs_initcall to core_initcall

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This patch splits trace event initialization in two stages:
 * ftrace enable
 * sysfs event entry creation

This allows to capture trace events from an earlier point
by using 'trace_event' kernel parameter and is important
to trace boot-up allocations.

Note that, in order to enable events at core_initcall,
it's necessary to move init_ftrace_syscalls() from
core_initcall to early_initcall.

Link: http://lkml.kernel.org/r/1347461277-25302-1-git-send-email-elezegarcia@gmail.com

Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Ezequiel Garcia 2012-09-12 11:47:57 -03:00 committed by Steven Rostedt
parent 5224c3a315
commit 8781915ad2
2 changed files with 73 additions and 37 deletions
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108
kernel/trace/trace_events.c
View file

@ -1199,6 +1199,31 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
return 0;
}
static void event_remove(struct ftrace_event_call *call)
{
ftrace_event_enable_disable(call, 0);
if (call->event.funcs)
__unregister_ftrace_event(&call->event);
list_del(&call->list);
}
static int event_init(struct ftrace_event_call *call)
{
int ret = 0;
if (WARN_ON(!call->name))
return -EINVAL;
if (call->class->raw_init) {
ret = call->class->raw_init(call);
if (ret < 0 && ret != -ENOSYS)
pr_warn("Could not initialize trace events/%s\n",
call->name);
}
return ret;
}
static int
__trace_add_event_call(struct ftrace_event_call *call, struct module *mod,
const struct file_operations *id,
@ -1209,19 +1234,9 @@ __trace_add_event_call(struct ftrace_event_call *call, struct module *mod,
struct dentry *d_events;
int ret;
/* The linker may leave blanks */
if (!call->name)
return -EINVAL;
if (call->class->raw_init) {
ret = call->class->raw_init(call);
if (ret < 0) {
if (ret != -ENOSYS)
pr_warning("Could not initialize trace events/%s\n",
call->name);
return ret;
}
}
ret = event_init(call);
if (ret < 0)
return ret;
d_events = event_trace_events_dir();
if (!d_events)
@ -1272,13 +1287,10 @@ static void remove_subsystem_dir(const char *name)
*/
static void __trace_remove_event_call(struct ftrace_event_call *call)
{
ftrace_event_enable_disable(call, 0);
if (call->event.funcs)
__unregister_ftrace_event(&call->event);
debugfs_remove_recursive(call->dir);
list_del(&call->list);
event_remove(call);
trace_destroy_fields(call);
destroy_preds(call);
debugfs_remove_recursive(call->dir);
remove_subsystem_dir(call->class->system);
}
@ -1450,15 +1462,43 @@ static __init int setup_trace_event(char *str)
}
__setup("trace_event=", setup_trace_event);
static __init int event_trace_enable(void)
{
struct ftrace_event_call **iter, *call;
char *buf = bootup_event_buf;
char *token;
int ret;
for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
call = *iter;
ret = event_init(call);
if (!ret)
list_add(&call->list, &ftrace_events);
}
while (true) {
token = strsep(&buf, ",");
if (!token)
break;
if (!*token)
continue;
ret = ftrace_set_clr_event(token, 1);
if (ret)
pr_warn("Failed to enable trace event: %s\n", token);
}
return 0;
}
static __init int event_trace_init(void)
{
struct ftrace_event_call **call;
struct ftrace_event_call *call;
struct dentry *d_tracer;
struct dentry *entry;
struct dentry *d_events;
int ret;
char *buf = bootup_event_buf;
char *token;
d_tracer = tracing_init_dentry();
if (!d_tracer)
@ -1497,24 +1537,19 @@ static __init int event_trace_init(void)
if (trace_define_common_fields())
pr_warning("tracing: Failed to allocate common fields");
for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
__trace_add_event_call(*call, NULL, &ftrace_event_id_fops,
/*
* Early initialization already enabled ftrace event.
* Now it's only necessary to create the event directory.
*/
list_for_each_entry(call, &ftrace_events, list) {
ret = event_create_dir(call, d_events,
&ftrace_event_id_fops,
&ftrace_enable_fops,
&ftrace_event_filter_fops,
&ftrace_event_format_fops);
}
while (true) {
token = strsep(&buf, ",");
if (!token)
break;
if (!*token)
continue;
ret = ftrace_set_clr_event(token, 1);
if (ret)
pr_warning("Failed to enable trace event: %s\n", token);
if (ret < 0)
event_remove(call);
}
ret = register_module_notifier(&trace_module_nb);
@ -1523,6 +1558,7 @@ static __init int event_trace_init(void)
return 0;
}
core_initcall(event_trace_enable);
fs_initcall(event_trace_init);
#ifdef CONFIG_FTRACE_STARTUP_TEST

2
kernel/trace/trace_syscalls.c
View file

@ -487,7 +487,7 @@ int __init init_ftrace_syscalls(void)
return 0;
}
core_initcall(init_ftrace_syscalls);
early_initcall(init_ftrace_syscalls);
#ifdef CONFIG_PERF_EVENTS