Re: [External] Re: [PATCH RESEND v3 1/2] ftrace: cleanup ftrace_graph_caller enable and disable

[Chengming Zhou <zhouchengming@bytedance.com>]

On 2022/4/9 22:23, Steven Rostedt wrote:
> On Sat,  9 Apr 2022 16:54:59 +0800
> Chengming Zhou <zhouchengming@bytedance.com> wrote:
> 
>> --- a/kernel/trace/ftrace.c
>> +++ b/kernel/trace/ftrace.c
>> @@ -2721,6 +2721,26 @@ int __weak ftrace_arch_code_modify_post_process(void)
>>  	return 0;
>>  }
>>  
>> +#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> 
> Actually, can you put this into fgraph.c instead. That only gets compiled
> if the above config is enabled. Thus, you do not even need to add the
> #ifdef around it.
> 
> I intend to move even more code into fgraph.c that is only for function
> graph. I don't want to add any new code to ftrace.c for it.

Ok, make sense. I will do it.

Thanks.

> 
> -- Steve
> 
> 
>> +/*
>> + * archs can override this function if they must do something
>> + * to enable hook for graph tracer.
>> + */
>> +int __weak ftrace_enable_ftrace_graph_caller(void)
>> +{
>> +	return 0;
>> +}
>> +
>> +/*
>> + * archs can override this function if they must do something
>> + * to disable hook for graph tracer.
>> + */
>> +int __weak ftrace_disable_ftrace_graph_caller(void)
>> +{
>> +	return 0;
>> +}
>> +#endif
>> +
>>  void ftrace_modify_all_code(int command)
>>  {
>>  	int update = command & FTRACE_UPDATE_TRACE_FUNC;
>