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

[Johannes Thumshirn <jthumshirn@suse.de>]

On Wed, Jan 18, 2017 at 05:14:36PM +0200, Sagi Grimberg wrote:
> 
> >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.

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Johannes Thumshirn                                          Storage
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