Re: [PATCH 1/2] tracepoints: Add helper to test if tracepoint is enabled in a header

Steven Rostedt
2020-09-25T15:14:24Z

On Fri, 25 Sep 2020 10:41:56 -0400 (EDT)
Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote:

> With the current dependencies of tracepoint.h, I would argue that we should
> only do the trampoline work-around for cases where there is an unavoidable
> circular dependency, like the case of msr.h. For other headers which don't
> have circular dependency issues with tracepoint.h, we should use the usual
> tracepoint instrumentation because not having the trampoline provides better
> tracing (on) speed and reduces (slightly) code size.

Well, for now, I'm going to add the helper function and have the header
use cases use that.

A while back ago I had patches that moves the DO_TRACE() work into a
separate function and with that we probably could have let all
tracepoints be in headers (as they would all just do a function call to
the trace algorithm that does the rest of the work). But you balked at
that because of the added overhead with tracing on.

Anyway, I don't see any issues with the current patch set as is
(besides the documentation fix, which I already updated locally). And
will add this to my queue for linux-next.

-- Steve