On Wed, 21 Aug 2024 21:27:55 +0800
Jeff Xie <jeff....@linux.dev> wrote:
Hi Jeff,
Thanks for the patch.
> Signed-off-by: Jeff Xie <jeff....@linux.dev>
> ---
> kernel/trace/trace_functions.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
> index 3b0cea37e029..273b8c7eeb2d 100644
> --- a/kernel/trace/trace_functions.c
> +++ b/kernel/trace/trace_functions.c
> @@ -176,6 +176,19 @@ static void function_trace_start(struct trace_array *tr)
> tracing_reset_online_cpus(&tr->array_buffer);
> }
>
> +static unsigned long
> +function_get_true_parent_ip(unsigned long parent_ip, struct ftrace_regs
> *fregs)
I wonder if we should make this inline, or even __always_inline, as this
will be called in a very hot path, and I want to make sure that the
compiler always inlines it. It likely should, but we should also give the
compiler a hint that it should.
-- Steve
> +{
> + unsigned long true_parent_ip;
> + int idx = 0;
> +
> + true_parent_ip = parent_ip;
> + if (unlikely(parent_ip == (unsigned long)&return_to_handler))
> + true_parent_ip = ftrace_graph_ret_addr(current, &idx, parent_ip,
> + (unsigned long *)fregs->regs.sp);
> + return true_parent_ip;
> +}
> +
> static void
> function_trace_call(unsigned long ip, unsigned long parent_ip,
> struct ftrace_ops *op, struct ftrace_regs *fregs)
> @@ -193,6 +206,8 @@ function_trace_call(unsigned long ip, unsigned long
> parent_ip,
> if (bit < 0)
> return;
>
> + parent_ip = function_get_true_parent_ip(parent_ip, fregs);
> +
> trace_ctx = tracing_gen_ctx();
>
> cpu = smp_processor_id();
> @@ -241,6 +256,7 @@ function_stack_trace_call(unsigned long ip, unsigned long
> parent_ip,
> * recursive protection is performed.
> */
> local_irq_save(flags);
> + parent_ip = function_get_true_parent_ip(parent_ip, fregs);
> cpu = raw_smp_processor_id();
> data = per_cpu_ptr(tr->array_buffer.data, cpu);
> disabled = atomic_inc_return(&data->disabled);
> @@ -309,6 +325,7 @@ function_no_repeats_trace_call(unsigned long ip, unsigned
> long parent_ip,
> if (bit < 0)
> return;
>
> + parent_ip = function_get_true_parent_ip(parent_ip, fregs);
> cpu = smp_processor_id();
> data = per_cpu_ptr(tr->array_buffer.data, cpu);
> if (atomic_read(&data->disabled))
> @@ -356,6 +373,7 @@ function_stack_no_repeats_trace_call(unsigned long ip,
> unsigned long parent_ip,
> * recursive protection is performed.
> */
> local_irq_save(flags);
> + parent_ip = function_get_true_parent_ip(parent_ip, fregs);
> cpu = raw_smp_processor_id();
> data = per_cpu_ptr(tr->array_buffer.data, cpu);
> disabled = atomic_inc_return(&data->disabled);
