Re: a bug in AS scheduler?

[Xiaoning Ding]

Jens Axboe wrote:
> On Wed, Feb 28 2007, Benoit Boissinot wrote:
> > On 2/28/07, Jens Axboe <jens.axboe@xxxxxxxxxx> wrote:
> > > On Tue, Feb 27 2007, Xiaoning Ding wrote:
> > > > Hi,
> > > >
> > > > I am reading the source code AS scheduler in 2.6.18(as-ioscheduler.c).
> > > > In function as_close_req, variable delay is in millisecond, while
> > > > ad->antic_expire is in jiffies. Doesn't the comparison of delay and
> > > > ad->antic_expire make any problem?
> > > > The related source code is quoted blow:
> > > >
> > > >       if (ad->antic_status == ANTIC_OFF || !ad->ioc_finished)
> > > >               delay = 0;
> > > >       else
> > > >               delay = ((jiffies - ad->antic_start) * 1000) / HZ;
> > > antic_start is in jiffies, the difference is here multiplied by 1000 and
> > > divided by HZ to turn it into msecs. so delay is in msecs.
> > I am pretty sure Xiaoning was talking about antic_expire, particularly
> > this comparison:
> >
> >     else if (delay <= 20 && delay <= ad->antic_expire)
>
> Ah, I misread the name. That does look like a bug, antic_expire is in
> jiffies.

You got it.

Xiaoning

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