Re: [PATCH 02/11 V5] workqueue: async idle rebinding

[Tejun Heo <tj@kernel.org>]

Hello, Lai.

Ooh, I like the approach.  That said, I think it's a bit too invasive
for 3.6-fixes.  I'll merge the two patches I posted yesterday in
3.6-fixes.  Let's do this restructuring in for-3.7.

On Wed, Sep 05, 2012 at 06:37:39PM +0800, Lai Jiangshan wrote:
>  static void idle_worker_rebind(struct worker *worker)
>  {
>  	struct global_cwq *gcwq = worker->pool->gcwq;
>  
> -	/* CPU must be online at this point */
> -	WARN_ON(!worker_maybe_bind_and_lock(worker));
> -	if (!--worker->idle_rebind->cnt)
> -		complete(&worker->idle_rebind->done);
> -	spin_unlock_irq(&worker->pool->gcwq->lock);
> +	if (worker_maybe_bind_and_lock(worker))
> +		worker_clr_flags(worker, WORKER_UNBOUND);
>  
> -	/* we did our part, wait for rebind_workers() to finish up */
> -	wait_event(gcwq->rebind_hold, !(worker->flags & WORKER_REBIND));
> +	worker_clr_flags(worker, WORKER_REBIND);
> +	list_add(&worker->entry, &worker->pool->idle_list);
> +	spin_unlock_irq(&gcwq->lock);

This looks correct to me but it's still a bit scary.  Some comments
explaining why the above is correct would be nice.

Yeah, other than that, looks good to me.  I'll prepare new for-3.7
branch this can be based on, so please wait a bit.  Also, I think I'll
probably update commit description / comments while committing.

Thanks!

-- 
tejun