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

Jens Axboe
2007-12-19T18:13:41Z

On Tue, Dec 18 2007, Nick Piggin wrote:
> 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...

Agree, will do so.

--
Jens Axboe