Thread (50 messages) 50 messages, 9 authors, 2017-01-20

Re: [LSF/MM TOPIC][LSF/MM ATTEND] NAPI polling for block drivers

From: Johannes Thumshirn <hidden>
Date: 2017-01-18 15:16:43
Also in: linux-nvme, linux-scsi

On Wed, Jan 18, 2017 at 05:14:36PM +0200, Sagi Grimberg wrote:
quoted
Hannes just spotted this:
static int nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
                        const struct blk_mq_queue_data *bd)
{
[...]
       __nvme_submit_cmd(nvmeq, &cmnd);
       nvme_process_cq(nvmeq);
       spin_unlock_irq(&nvmeq->q_lock);
       return BLK_MQ_RQ_QUEUE_OK;
out_cleanup_iod:
       nvme_free_iod(dev, req);
out_free_cmd:
       nvme_cleanup_cmd(req);
       return ret;
}

So we're draining the CQ on submit. This of cause makes polling for
completions in the IRQ handler rather pointless as we already did in the
submission path.
I think you missed:
http://git.infradead.org/nvme.git/commit/49c91e3e09dc3c9dd1718df85112a8cce3ab7007
I indeed did, thanks.

-- 
Johannes Thumshirn                                          Storage
jthumshirn@suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N�rnberg
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HRB 21284 (AG N�rnberg)
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