linux-kernel - Re: [PATCH] drm/radeon: Remove deprecated create_singlethread

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Date:	Tue, 5 Jul 2016 17:06:44 -0400
From:	Tejun Heo <tj@...nel.org>
To:	Michel Dänzer <michel@...nzer.net>
Cc:	Bhaktipriya Shridhar <bhaktipriya96@...il.com>,
	Alex Deucher <alexander.deucher@....com>,
	Christian König <christian.koenig@....com>,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/radeon: Remove deprecated
 create_singlethread_workqueue

Hello,

On Mon, Jul 04, 2016 at 12:58:32PM +0900, Michel Dänzer wrote:
> On 02.07.2016 22:46, Tejun Heo wrote:
> > On Sat, Jul 02, 2016 at 04:33:50PM +0530, Bhaktipriya Shridhar wrote:
> >> alloc_workqueue replaces deprecated create_singlethread_workqueue().
> >>
> >> A dedicated workqueue has been used since work items need to be flushed
> >> as a group rather than individually.

There seem to be two work items involved, the flip one and unpin one.
Provided that there's no ordering requirement between the two, can't
we just flush them individually?

> >> Since the flip_queue workqueue is involved in page-flipping and is not
> >> being used on a memory reclaim path, WQ_MEM_RECLAIM has not been set.
> >>
> >> Since there are only a fixed number of work items, explicit concurrency
> >> limit is unnecessary here.
> > 
> > What are the involved work items?
> 
> drivers/gpu/drm/radeon/radeon_display.c:radeon_flip_work_func()
>
> > Is it safe to run them concurrently?
> 
> Concurrently with what exactly?

The flip and unpin work items.

Thanks.

-- 
tejun