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

[Alexei Starovoitov]

On Fri, Jan 9, 2026 at 6:45 AM Mathieu Desnoyers
<mathieu.desnoyers@xxxxxxxxxxxx> wrote:
>
> On 2026-01-08 22:05, Steven Rostedt wrote:
> > From: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
> [...]
>
> I disagree with many elements of the proposed approach.
>
> On one end we have BPF wanting to hook on arbitrary tracepoints without
> adding significant latency to PREEMPT RT kernels.
>
> One the other hand, we have high-speed tracers which execute very short
> critical sections to serialize trace data into ring buffers.
>
> All of those users register to the tracepoint API.
>
> We also have to consider that migrate disable is *not* cheap at all
> compared to preempt disable.

Looks like your complaint comes from lack of engagement in kernel
development.
migrate_disable _was_ not cheap.
Try to benchmark it now.
It's inlined. It's a fraction of extra overhead on top of preempt_disable.