On Fri, Jul 08, 2016 at 11:57:10AM -0400, Steven Rostedt wrote: > On Fri, 8 Jul 2016 10:48:24 -0500 > Josh Poimboeuf <jpoim...@redhat.com> wrote: > > > > Here, with -fprolog-pad, it's already a nop, so no change is needed. > >
Yes, exactly. > That's what I was thinking. But as I stated in another email (probably > in the air when you wrote this), the call to ftrace_modify_code() may be > completely circumvented by ftrace_make_nop() if the addr is MCOUNT_ADDR. Only on the _first_ invocation. Later on, tracing can be switched on and off, and then the instructions need to be changed just like with fentry (or profile-kernel ;-) Torsten