coalescing in polling mode in 4.9

[Keith Busch]

On Sat, Feb 10, 2018 at 01:08:17PM -0800, Alex Nln wrote:
> It is quite strange model of IO processing: polling with interrupts. 
> Shouldn't these two be mutual exclusive? Why not to disable
> interrupts at all on a queue while polling?

That's a valid point. There are some limitations preventing this at the
moment. The nvme driver currently does not have a way to know the command
it is submitting is intended to be polled, and if it did, we still need
to determine a policy for creating special queue or queues that have
interrupts disabled and how we register these with the block layer.