[PATCH] NVMe: Avoid caculate cq head doorbel in nvme_process_cq()

[Matthew Wilcox]

On Mon, Sep 02, 2013 at 06:49:34AM +0000, Huhaiyan (haiyan) wrote:
> We use 2 pointers, one for sq tail doorbell, the other for cq head doorbell in struct nvme_queue, to avoid calculate cq head doorbell in nvme_process_cq(). 
> This change can reduce latency for the admin/io command.

Have you been able to measure a difference?  If so, can you share
relative numbers?