Move trace_eval_init() to subsys_initcall to make it start
earlier.
And to avoid tracer_init_tracefs being blocked by
trace_event_sem which trace_eval_init() hold [1],
queue tracer_init_tracefs() to eval_map_wq to let
the two works being executed sequentially.
It can speed up the initialization of kernel as result
of making tracer_init_tracefs asynchronous.
On my arm64 platform, it reduce ~20ms of 125ms which total
time do_initcalls spend.
[1]: https://lore.kernel.org/r/68d7b3327052757d0cd6359a6c9015a85b437232.camel@pengutronix.de
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
---
kernel/trace/trace.c | 31 +++++++++++++++++++++----------
1 file changed, 21 insertions(+), 10 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 85ec758c4455..2974ae056068 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -9571,6 +9571,7 @@ extern struct trace_eval_map *__stop_ftrace_eval_maps[];
static struct workqueue_struct *eval_map_wq __initdata;
static struct work_struct eval_map_work __initdata;
+static struct work_struct tracerfs_init_work __initdata;
static void __init eval_map_work_func(struct work_struct *work)
{
@@ -9596,6 +9597,8 @@ static int __init trace_eval_init(void)
return 0;
}
+subsys_initcall(trace_eval_init);
+
static int __init trace_eval_sync(void)
{
/* Make sure the eval map updates are finished */
@@ -9678,15 +9681,8 @@ static struct notifier_block trace_module_nb = {
};
#endif /* CONFIG_MODULES */
-static __init int tracer_init_tracefs(void)
+static __init void tracer_init_tracefs_work_func(struct work_struct *work)
{
- int ret;
-
- trace_access_lock_init();
-
- ret = tracing_init_dentry();
- if (ret)
- return 0;
event_trace_init();
@@ -9708,8 +9704,6 @@ static __init int tracer_init_tracefs(void)
trace_create_file("saved_tgids", TRACE_MODE_READ, NULL,
NULL, &tracing_saved_tgids_fops);
- trace_eval_init();
-
trace_create_eval_file(NULL);
#ifdef CONFIG_MODULES
@@ -9724,6 +9718,23 @@ static __init int tracer_init_tracefs(void)
create_trace_instances(NULL);
update_tracer_options(&global_trace);
+}
+
+static __init int tracer_init_tracefs(void)
+{
+ int ret;
+
+ trace_access_lock_init();
+
+ ret = tracing_init_dentry();
+ if (ret)
+ return 0;
+
+ INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func);
+ if (!eval_map_wq)
+ tracer_init_tracefs_work_func(&tracerfs_init_work);
+ else
+ queue_work(eval_map_wq, &tracerfs_init_work);
return 0;
}
--
2.18.0
On Wed, 23 Mar 2022 23:22:57 +0800 Mark-PK Tsai <mark-pk.tsai@mediatek.com> wrote: > +static __init int tracer_init_tracefs(void) > +{ > + int ret; > + > + trace_access_lock_init(); > + > + ret = tracing_init_dentry(); > + if (ret) > + return 0; > + > + INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func); > + if (!eval_map_wq) > + tracer_init_tracefs_work_func(&tracerfs_init_work); Why go through the bother of doing the INIT_WORK if eval_map_wq is not created? Just do: if (eval_map_wq) { INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func); queue_work(eval_map_wq, &tracerfs_init_work); } else { tracer_init_tracefs_work_func(NULL); } But that's just a nit anyway. -- Steve > + else > + queue_work(eval_map_wq, &tracerfs_init_work); > > return 0; > }
> > +static __init int tracer_init_tracefs(void) > > +{ > > + int ret; > > + > > + trace_access_lock_init(); > > + > > + ret = tracing_init_dentry(); > > + if (ret) > > + return 0; > > + > > + INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func); > > + if (!eval_map_wq) > > + tracer_init_tracefs_work_func(&tracerfs_init_work); > > Why go through the bother of doing the INIT_WORK if eval_map_wq is not > created? Just do: > > if (eval_map_wq) { > INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func); > queue_work(eval_map_wq, &tracerfs_init_work); > } else { > tracer_init_tracefs_work_func(NULL); > } Got it, I will update it in v4. Thanks! > > But that's just a nit anyway. > > -- Steve > > > > > + else > > + queue_work(eval_map_wq, &tracerfs_init_work); > > > > return 0; > > }
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