Re: [PATCH] [media] sn9c20x: Remove deprecated create_singlethread_workqueue

From: Tejun Heo
Date: Sat Jul 02 2016 - 09:42:53 EST


On Sat, Jul 02, 2016 at 04:21:22PM +0530, Bhaktipriya Shridhar wrote:
> The workqueue "work_thread" is involved in JPEG quality update.
> It has a single work item(&sd->work) and hence doesn't require ordering.
> Also, it is not being used on a memory reclaim path. Hence, the
> singlethreaded workqueue has been replaced with the use of system_wq.
>
> System workqueues have been able to handle high level of concurrency
> for a long time now and hence it's not required to have a singlethreaded
> workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue
> created with create_singlethread_workqueue(), system_wq allows multiple
> work items to overlap executions even on the same CPU; however, a
> per-cpu workqueue doesn't have any CPU locality or global ordering
> guarantee unless the target CPU is explicitly specified and thus the
> increase of local concurrency shouldn't make any difference.
>
> Work item has been flushed in sd_stop0() to ensure that there are no
> pending tasks while disconnecting the driver.
>
> Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@xxxxxxxxx>

Acked-by: Tejun Heo <tj@xxxxxxxxxx>

Thanks.

--
tejun