Re: [PATCH 4/9 V3] workqueue: addnon_manager_role_manager_mutex_unlock()

From: Tejun Heo
Date: Wed Aug 29 2012 - 14:25:07 EST


On Thu, Aug 30, 2012 at 12:51:55AM +0800, Lai Jiangshan wrote:
> If hotplug code grabbed the manager_mutex and worker_thread try to create
> a worker, the manage_worker() will return false and worker_thread go to
> process work items. Now, on the CPU, all workers are processing work items,
> no idle_worker left/ready for managing. It breaks the concept of workqueue
> and it is bug.
>
> So when this case happens, the last idle should not go to process work,
> it should go to sleep as usual and wait normal events. but it should
> also be notified by the event that hotplug code release the manager_mutex.
>
> So we add non_manager_role_manager_mutex_unlock() to do this notify.

Hmmm... how about just running rebind_workers() from a work item?
That way, it would be guaranteed that there alwyas will be an extra
worker available on rebind completion.

Thanks.

--
tejun
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