Re: [Question] sched: Should nr_uninterruptible be decremented inttwu_do_activate()?

From: Peter Zijlstra
Date: Thu Jan 12 2012 - 15:26:24 EST


On Thu, 2012-01-12 at 23:08 +0600, Rakib Mullick wrote:

> That might be the case for scheduler_ipi(), but when
> sched_ttwu_pending() gets called when a cpu goes down, all tasks from
> wake_list of that cpu has been moved without TASK_WAKING is set. For a
> particular task it might be possible that when it ran previously it
> had p->sched_contributes_to_load is set. Latter, this task's cpu has
> been put down and calls sched_ttwu_pending(), then for that task
> p->sched_contributes_to_load is set and TASK_WAKING is not set.
> Couldn't be happen?

No, look again, its impossible to be on that list and not be
TASK_WAKING.

The only way onto the list is through ttwu_queue_remote(), the only way
off the list is through sched_ttwu_pending().
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/