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

From: Tejun Heo
Date: Sat Jul 02 2016 - 09:59:02 EST


On Sat, Jul 02, 2016 at 04:17:31PM +0530, Bhaktipriya Shridhar wrote:
> The workqueue "workqueue" is involved in tranmitting hdpvr buffers.
> It has a single work item(&dev->worker) 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 hdpvr_device_release() 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