From mboxrd@z Thu Jan 1 00:00:00 1970 From: keith.busch@intel.com (Keith Busch) Date: Thu, 21 Dec 2017 13:46:34 -0700 Subject: [PATCH 1/3] nvme/pci: Start request after doorbell ring In-Reply-To: <20171221204636.2924-1-keith.busch@intel.com> References: <20171221204636.2924-1-keith.busch@intel.com> Message-ID: <20171221204636.2924-2-keith.busch@intel.com> This is a performance optimization that allows the hardware to work on a command in parallel with the kernel's stats and timeout tracking. Signed-off-by: Keith Busch --- drivers/nvme/host/pci.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index f5800c3c9082..df5550ce0531 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -886,8 +886,6 @@ static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx *hctx, goto out_cleanup_iod; } - blk_mq_start_request(req); - spin_lock_irq(&nvmeq->q_lock); if (unlikely(nvmeq->cq_vector < 0)) { ret = BLK_STS_IOERR; @@ -895,6 +893,7 @@ static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx *hctx, goto out_cleanup_iod; } __nvme_submit_cmd(nvmeq, &cmnd); + blk_mq_start_request(req); nvme_process_cq(nvmeq); spin_unlock_irq(&nvmeq->q_lock); return BLK_STS_OK; -- 2.13.6