[dm-devel] [PATCH 3/2] dm: table load must always try dm_setup_md_queue
Mike Snitzer
snitzer at redhat.com
Wed Jun 9 08:53:46 UTC 2010
On Wed, Jun 09 2010 at 1:38am -0400,
Kiyoshi Ueda <k-ueda at ct.jp.nec.com> wrote:
> Hi Mike,
>
> On 06/05/2010 05:15 AM +0900, Mike Snitzer wrote:
> > @@ -2164,7 +2164,8 @@ static int dm_init_request_based_queue(s
> > {
> > struct request_queue *q = NULL;
> >
> > - BUG_ON(md->queue->elevator);
> > + if (unlikely(md->queue->elevator))
> > + return 1;
>
> I think the "unlikely" should be rather "likely", since
> dm_init_request_based_queue() is now called whenever request-based
> table is loaded even after the actual initialization has been done.
Yes, good point. Though I'd expect reloading a request-based table is
actually fairly rare. Is it really all that worthwhile to have any
branch prediction here? Should we just remove the likely/unlikely
entirely?
Thanks,
Mike
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