[PATCH] nvme: Acknowledge completion queue on each iteration

[Keith Busch]

On Mon, Jul 17, 2017 at 06:36:23PM -0400, Sinan Kaya wrote:
> Code is moving the completion queue doorbell after processing all completed
> events and sending callbacks to the block layer on each iteration.
> 
> This is causing a performance drop when a lot of jobs are queued towards
> the HW. Move the completion queue doorbell on each loop instead and allow new
> jobs to be queued by the HW.

That doesn't make sense. Aggregating doorbell writes should be much more
efficient for high depth workloads.