On 3/28/18 11:10 AM, Steven Rostedt wrote:

On Wed, 28 Mar 2018 11:03:24 -0700
Alexei Starovoitov [off-list ref] wrote:

quoted

I can live with this overhead if Mathieu insists,
but I prefer to keep it in 'struct tracepoint'.

Thoughts?

I'm fine with keeping it as is. We could probably use it for future
enhancements in perf and ftrace.

Perhaps, we should just add a:

#ifdef CONFIG_BPF_EVENTS

Around the use cases of num_args.

it sounds like a good idea, but implementation wise
it will be ifdef CONFIG_BPF_EVENTS around u32 num_args;
in struct tracepoint and similar double definition of
DEFINE_TRACE_FN. One that uses num_args to init
struct tracepoint and one that doesn't ?
Feels like serious uglification of already macros heavy code.
Also what it will address?
cache hot/cold argument clearly doesn't apply.