Re: [patch 4/8] x86/entry: Move irq tracing on syscall entry to C-code

[Steven Rostedt]

On Sun, 01 Mar 2020 16:21:15 +0100
Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:

> Andy Lutomirski <luto@xxxxxxxxxxxxxx> writes:
> >> On Mar 1, 2020, at 2:16 AM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> >> Ok, but for the time being anything before/after CONTEXT_KERNEL is unsafe
> >> except trace_hardirq_off/on() as those trace functions do not allow to
> >> attach anything AFAICT.  
> >
> > Can you point to whatever makes those particular functions special?  I
> > failed to follow the macro maze.  
> 
> Those are not tracepoints and not going through the macro maze. See
> kernel/trace/trace_preemptirq.c

For the latency tracing, they do call into the tracing infrastructure,
not just lockdep. And Joel Fernandez did try to make these into trace
events as well.

-- Steve