Re: [PATCH] usb: lvstest: Remove deprecated create_singlethread_workqueue

From: Tejun Heo
Date: Fri Jul 29 2016 - 09:17:29 EST

On Thu, Jul 28, 2016 at 02:15:11PM +0530, Bhaktipriya Shridhar wrote:
> The workqueue has a single work item(&lvs->rh_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.
> The work item has been flushed in lvs_rh_disconnect() 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>