Messages in this thread | | | Date | Thu, 10 Nov 2005 18:10:52 +0100 | From | Jens Axboe <> | Subject | Re: [PATCH] cfq-iosched: fix slice_left calculation |
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On Thu, Nov 10 2005, Tejun Heo wrote: > When cfq slice expires, remainder of slice is calculated and stored in > cfqq->slice_left. Current code calculates the opposite of remainder - > how many jiffies the cfqq has used past slice end. This patch fixes > the bug. > > Signed-off-by: Tejun Heo <htejun@gmail.com> > > diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c > --- a/block/cfq-iosched.c > +++ b/block/cfq-iosched.c > @@ -861,8 +861,8 @@ __cfq_slice_expired(struct cfq_data *cfq > * store what was left of this slice, if the queue idled out > * or was preempted > */ > - if (time_after(now, cfqq->slice_end)) > - cfqq->slice_left = now - cfqq->slice_end; > + if (time_after(cfqq->slice_end, now)) > + cfqq->slice_left = cfqq->slice_end - now; > else > cfqq->slice_left = 0;
That looks more correct, good spotting. Applied.
-- Jens Axboe
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