From: sunliming <[email protected]> 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 <[email protected]> --- 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
