Re: [patch 6/9] blk: unplug later

[Jens Axboe]

On Wed, Apr 13 2005, Nick Piggin wrote:
> Andrew Morton wrote:
> >Nick Piggin <nickpiggin@xxxxxxxxxxxx> wrote:
> >
> >>get_request_wait needn't unplug the device immediately.
> >
> >
> >Probably.  But what if the get_request(q, rw, GFP_NOIO); did
> >some sleeping?
> >
> 
> It can't sleep unless it returns the request, because it
> is using mempool allocs. So any time it returns NULL, it
> hasn't slept.
> 
> But Jens would have a better idea of the correct behaviour.
> Jens, what do you think?

I think the patch makes sense. Additionally, it looks safer to unplug in
the loop as well - not just as an optimization for the first run, but
further loops of the code may need to trigger an unplug of the queue.

-- 
Jens Axboe

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