Re: [PATCH v2] gpu: host1x: hw: intr_hw: Remove create_workqueue

[Tejun Heo]

On Sat, Jun 18, 2016 at 02:36:32PM +0530, Bhaktipriya Shridhar wrote:
> System workqueues have been able to handle high level of concurrency
> for a long time now and there's no reason to use dedicated workqueues
> just to gain concurrency. Since the workqueue host->intr_wq is involved
> in sync point interrupts, and sync point wait and is not being used on
> a memory reclaim path, dedicated host->intr_wq has been replaced with the
> use of system_wq.
> 
> Unlike a dedicated per-cpu workqueue created with create_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 guarantees unless the target CPU is
> explicitly specified and thus the increase of local concurrency
> shouldn't make any difference.
> 
> cancel_work_sync() has been used  in _host1x_free_syncpt_irq() to ensure
> that no work is pending by the time exit path runs.

Alternatively, this could have used alloc_workqueue() w/o
WQ_MEM_RECLAIM and used it just as a flush domain.  Either way is
fine.

Acked-by: Tejun Heo <tj@xxxxxxxxxx>

Thanks.

-- 
tejun