Re: [PATCH 2/3] tracing: Use in_serving_softirq() to deduct softirq status.

On Wed, 13 Jan 2021 00:00:56 +0100 Sebastian Andrzej Siewior wrote: > Use in_serving_softirq() macro which works on PREEMPT_RT. On !PREEMPT_RT > the compiler (gcc-10 / clang-11) is smart enough to optimize the > in_serving_softirq() related read of the preemption counter away. > The only differen

[PATCH 2/3] tracing: Use in_serving_softirq() to deduct softirq status.

PREEMPT_RT does not report "serving softirq" because the tracing core looks at the preemption counter while PREEMPT_RT does not update it while processing softirqs in order to remain preemptible. The information is stored somewhere else. The in_serving_softirq() macro and the SOFTIRQ_OFFSET define