Re: [RFC]cfq-iosched: improve hw_tag detection

From: Jens Axboe
Date: Tue Oct 27 2009 - 03:45:49 EST


On Tue, Oct 27 2009, Shaohua Li wrote:
> On Mon, Oct 26, 2009 at 07:35:55PM +0800, Jens Axboe wrote:
> > On Mon, Oct 26 2009, Shaohua Li wrote:
> > > If active queue hasn't enough requests and idle window opens, cfq will not
> > > dispatch sufficient requests to hardware. In such situation, current code
> > > will zero hw_tag. But this is because cfq doesn't dispatch enough requests
> > > instead of hardware queue doesn't work. Don't zero hw_tag in such case.
> >
> > Thanks, that looks like a good fix. Curious, is this fixing some
> > regression at your end?
> No, just observed such issue when I play with cfq.

OK thanks, just curious. I will apply it for 2.6.33.

--
Jens Axboe

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