Re: [PATCH 1/4] cpu_stop: implement stop_cpu[s]()
From: Peter Zijlstra
Date: Mon May 03 2010 - 09:27:50 EST
On Thu, 2010-04-22 at 18:09 +0200, Tejun Heo wrote:
> +static int cpu_stopper_thread(void *data)
> +{
> + struct cpu_stopper *stopper = data;
BUG_ON(stopper != __get_cpu_var(cpu_stopper)); ?
> + work = NULL;
> + spin_lock_irq(&stopper->lock);
> + if (!list_empty(&stopper->works)) {
> + work = list_first_entry(&stopper->works,
> + struct cpu_stop_work, list);
> + list_del_init(&work->list);
> + }
> + spin_unlock_irq(&stopper->lock);
Not sure if its worth the hassle, but you could list_splice_init() the
complete pending list onto a local list, possible avoiding some locks.
But since this isn't supposed to be used much, I doubt we'll ever see
the difference.
> + /* restore preemption and check it's still balanced */
> + preempt_enable();
> + WARN_ON_ONCE(preempt_count());
You would use WARN_ONCE() and print the function that last ran and
leaked the preempt count.
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