Subject: Re: [PATCH 2/3] workqueue: Add an API to create a singlethread workqueue attached to the current task's cgroup

From: Tejun Heo <[email-masked]>
Date: Thu, 27 May 2010 18:56:20 +0200

Hello,

On 05/27/2010 06:39 PM, Michael S. Tsirkin wrote:
>> Unless you're gonna convert every driver to use this
>> special kind of workqueue (and what happens when multiple tasks from
>> different cgroups share the driver?),
> 
> We'll then create a workqueue per task. Each workqueue will have the
> right cgroup. But we are not trying to selve the problem for
> every driver.

Ah... I see.  You're gonna use multiple workqueues.  Once concern that
I have is that this is abuse of workqueue interface to certain level
and depends on the implementation detail of workqueue rather than its
intended usage model.  stop_machine() was a similar case and in the
end it was better served by a different mechanism built on kthread
directly (cpu_stop).  Wouldn't it be cleaner to use kthread directly
for your case too?  You're basically trying to use workqueue as a
frontend to kthread, so...

Thanks.

-- 
tejun