Commit 0c2580a8 authored by Yaxiong Tian's avatar Yaxiong Tian Committed by Steven Rostedt (Google)
Browse files

blktrace: Make init_blk_tracer() asynchronous 

The init_blk_tracer() function causes significant boot delay as it
waits for the trace_event_sem lock held by trace_event_update_all().
Specifically, its child function register_trace_event() requires
this lock, which is occupied for an extended period during boot.

To resolve this, the execution of primary init_blk_tracer() is moved
to the trace_init_wq workqueue, allowing it to run asynchronously,
and prevent blocking the main boot thread.

Link: https://patch.msgid.link/20260204015353.163331-1-tianyaxiong@kylinos.cn


Acked-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: default avatarYaxiong Tian <tianyaxiong@kylinos.cn>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 1c48f7ab

kernel/trace/blktrace.c

+22 −1
Original line number Diff line number Diff line
@@ -1832,7 +1832,9 @@ static struct trace_event trace_blk_event = { 
	.funcs		= &trace_blk_event_funcs,

};



static int __init init_blk_tracer(void)

static struct work_struct blktrace_works __initdata;



static int __init __init_blk_tracer(void)

{

	if (!register_trace_event(&trace_blk_event)) {

		pr_warn("Warning: could not register block events\n");
@@ -1852,6 +1854,25 @@ static int __init init_blk_tracer(void) 
	return 0;

}



static void __init blktrace_works_func(struct work_struct *work)

{

	__init_blk_tracer();

}



static int __init init_blk_tracer(void)

{

	int ret = 0;



	if (trace_init_wq) {

		INIT_WORK(&blktrace_works, blktrace_works_func);

		queue_work(trace_init_wq, &blktrace_works);

	} else {

		ret = __init_blk_tracer();

	}



	return ret;

}



device_initcall(init_blk_tracer);



static int blk_trace_remove_queue(struct request_queue *q)