Re: [PATCH 2/3] rcu: Defer RCU kthreads wakeup when CPU is dying

Cheng-Jui Wang (王正睿)
2024-08-12T11:53:27Z

On Mon, 2024-08-12 at 13:13 +0200, Frederic Weisbecker wrote:
>
> This means you are setting rcuo kthreads as real time
> tasks. I would be curious about your usecase.

I think it might simply be that CONFIG_RCU_BOOST=y was enabled. This
causes kthread_prio to be set to 1.

static int kthread_prio = IS_ENABLED(CONFIG_RCU_BOOST) ? 1 : 0;

Then, when creating rcuog kthread, since kthread_prio is 1, it will
automatically set it to SCHED_FIFO.

t = kthread_run(..., "rcuog/%d", ...);
...
if (kthread_prio)
sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);

Thanks.