Re: [PATCH v2] spi: spi-sh: Remove deprecated create_singlethread_workqueue

From: Tejun Heo
Date: Tue Jul 12 2016 - 14:44:41 EST


On Sun, Jul 10, 2016 at 07:55:19PM +0530, Bhaktipriya Shridhar wrote:
> The workqueue has a single workitem(&ss->ws) 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 spi_sh_remove() 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