Re: [PATCH 03/10 V2] workqueue: async worker destruction

Tejun Heo
2014-05-13T14:14:23Z

Hello,

On Tue, May 13, 2014 at 02:32:52PM +0800, Lai Jiangshan wrote:
> >> + if (detach_completion)
> >> + complete(detach_completion);
> >> +}
> >
> > Are we gonna use this function from somewhere else too?
>
> it is called from worker_thread().
>
> I don't want to unfold it into worker_thread(), it is better
> readability when it is wrapped and it will be called in patch10
> for rescuer.

Yeah, it's shared by rescuer later, so it's fine but, again, it
probably helps to mention that it's planned to do so; otherwise, the
rationale is kinda weak and what belongs to that function is rather
arbitrary.

> >> /*
> >> * Become the manager and destroy all workers. Grabbing
> >> - * manager_arb prevents @pool's workers from blocking on
> >> - * manager_mutex.
> >> + * manager_arb ensures manage_workers() finish and enter idle.
> >
> > I don't follow what the above comment update is trying to say.
>
> If a pool is destroying, the worker will not call manage_workers().
> but the existing manage_workers() may be still running.
>
> mutex_lock(&manager_arb) in put_unbound_pool() should wait this manage_workers()
> finished due to the manager-worker (non-idle-worker) can't be destroyed.

Hmmm... I think it'd be better to spell it out then. The single
sentence is kinda cryptic especially because the two verbs in the
sentence don't have the same subject (managee_workers() can't enter
idle).

Thanks.

--
tejun