Re: [RFC] usb: host: u132-hcd: Remove deprecated create_singlethread_workqueue

From: Tejun Heo
Date: Wed Jul 27 2016 - 14:00:56 EST


Hello, Oliver.

On Wed, Jul 27, 2016 at 11:29:56AM +0200, Oliver Neukum wrote:
> On Wed, 2016-07-27 at 14:50 +0530, Bhaktipriya Shridhar wrote:
> > The workqueue "workqueue" has multiple workitems which may require
> > ordering. Hence, a dedicated ordered workqueue has been used.
> > Since the workqueue is not being used on a memory reclaim path,
> > WQ_MEM_RECLAIM has not been set.
>
> That is incorrect. The work queue is used by the HCD to handle
> TDs, which are parts of basic IO. The HCD in turn is used by
> usb-storage and uas, which are block drivers and those are obviously
> used on the memory reclaim path.

Hmm... I didn't know the whole USB stack could operate without
allocating memory. Does usb stack have mempools and stuff all the way
through?

Thanks.

--
tejun