Re: [PATCH v5] tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast

[Steven Rostedt]

On Mon, 12 Jan 2026 16:31:28 +0100
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> > OUCH! So migrate disable/enable has a much larger overhead when executed in
> > a module than in the kernel? This means all spin_locks() in modules
> > converted to mutexes in PREEMPT_RT are taking this hit!  
> 
> Not so, the migrate_disable() for PREEMPT_RT is still in core code --
> kernel/locking/spinlock_rt.c is very much not build as a module.

True. But still, wouldn't it be cleaner to have that variable separate from
the run queue and make the code a bit simpler?

As now it doesn't look like it will even bother tracing, as it appears that
only BPF would need it. So this would just be a clean up.

-- Steve