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

From: Tejun Heo
Date: Wed Sep 05 2012 - 14:06:34 EST


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
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