[PATCH v2] tracing: kprobe-event: Return directly when trace kprobes is empty

[PATCH v2] tracing: kprobe-event: Return directly when trace kprobes is empty

[sunliming]

From: sunliming <sunliming@kylinos.cn>

In enable_boot_kprobe_events(), it returns directly when trace kprobes is
empty, thereby reducing the function's execution time. This function may
otherwise wait for the event_mutex lock for tens of milliseconds on certain
machines, which is unnecessary when trace kprobes is empty.

Signed-off-by: sunliming <sunliming@kylinos.cn>
---
v2:
- wrap the the null check for the dyn_event_list with macro trace_kprobe_list_empty
---
 kernel/trace/trace_kprobe.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 9953506370a5..95f2c42603d5 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -82,6 +82,7 @@ static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
 #define for_each_trace_kprobe(pos, dpos)	\
 	for_each_dyn_event(dpos)		\
 		if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
+#define trace_kprobe_list_empty() list_empty(&dyn_event_list)
 
 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
 {
@@ -1982,6 +1983,9 @@ static __init void enable_boot_kprobe_events(void)
 	struct trace_kprobe *tk;
 	struct dyn_event *pos;
 
+	if (trace_kprobe_list_empty())
+		return;
+
 	guard(mutex)(&event_mutex);
 	for_each_trace_kprobe(tk, pos) {
 		list_for_each_entry(file, &tr->events, list)
-- 
2.25.1

Re: [PATCH v2] tracing: kprobe-event: Return directly when trace kprobes is empty

[Masami Hiramatsu]

On Tue, 27 Jan 2026 13:38:48 +0800
sunliming@linux.dev wrote:

> From: sunliming <sunliming@kylinos.cn>
> 
> In enable_boot_kprobe_events(), it returns directly when trace kprobes is
> empty, thereby reducing the function's execution time. This function may
> otherwise wait for the event_mutex lock for tens of milliseconds on certain
> machines, which is unnecessary when trace kprobes is empty.
> 
> Signed-off-by: sunliming <sunliming@kylinos.cn>

Looks good to me. Let me pick it.

Thanks, 


> ---
> v2:
> - wrap the the null check for the dyn_event_list with macro trace_kprobe_list_empty
> ---
>  kernel/trace/trace_kprobe.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 9953506370a5..95f2c42603d5 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -82,6 +82,7 @@ static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
>  #define for_each_trace_kprobe(pos, dpos)	\
>  	for_each_dyn_event(dpos)		\
>  		if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
> +#define trace_kprobe_list_empty() list_empty(&dyn_event_list)
>  
>  static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
>  {
> @@ -1982,6 +1983,9 @@ static __init void enable_boot_kprobe_events(void)
>  	struct trace_kprobe *tk;
>  	struct dyn_event *pos;
>  
> +	if (trace_kprobe_list_empty())
> +		return;
> +
>  	guard(mutex)(&event_mutex);
>  	for_each_trace_kprobe(tk, pos) {
>  		list_for_each_entry(file, &tr->events, list)
> -- 
> 2.25.1
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>