Re: [rfc][patch 1/3] block: non-atomic queue_flags prep

Nick Piggin
2007-12-18T08:13:52Z

On Tue, Dec 18, 2007 at 08:44:40AM +0100, Jens Axboe wrote:
> On Sat, Dec 15 2007, Nick Piggin wrote:
> > Hi,
> >
> > This is just an idea I had, which might make request processing a little
> > bit cheaper depending on queue behaviour. For example if it is getting plugged
> > unplugged frequently (as I think is the case for some database workloads),
> > then we might save one or two atomic operations per request.
> >
> > Anyway, I'm not completely sure if I have ensured all queue_flags users are
> > safe (I think md may need a bit of help). But overall it seems quite doable.
>
> Looks ok to me, I'll throw it into the testing mix. Thanks Nick!

OK... actually if you are expecting it to be widely tested, can you change
the BUG_ONs in queue_flag_set / queue_flag_clear into WARN_ON?

That way it's less likely to take down people's systems...

Thanks!