Re: [TIP/SCHED/DEVEL PATCH v3 4/6] sched: add sched_class->needs_post_schedule()member

From: Steven Rostedt
Date: Thu Sep 04 2008 - 16:37:50 EST




On Thu, 4 Sep 2008, Gregory Haskins wrote:
> diff --git a/kernel/sched.c b/kernel/sched.c
> index af4c6fa..ddc3877 100644
> --- a/kernel/sched.c
> +++ b/kernel/sched.c
> @@ -2525,6 +2525,14 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
> {
> struct mm_struct *mm = rq->prev_mm;
> long prev_state;
> +#ifdef CONFIG_SMP
> + int post_schedule = 0;
> +
> + if (current->sched_class->needs_post_schedule) {
> + BUG_ON(!current->sched_class->post_schedule);

The only one to ever hit this BUG_ON is a kernel developer creating a new
sched class. Since they should be smart enough to figure out why they get
a segv later on, we really don't need it. Because this BUG_ON is also in
a hot path, I strongly suggest nuking it.

-- Steve


> + post_schedule = current->sched_class->needs_post_schedule(rq);
> + }
> +#endif
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