Messages in this thread | | | Date | Mon, 19 Jul 2010 17:04:34 -0400 | From | Vivek Goyal <> | Subject | Re: [PATCH 2/3] cfq-iosched: Implement a new tunable group_idle |
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On Mon, Jul 19, 2010 at 01:54:53PM -0700, Divyesh Shah wrote: > On Mon, Jul 19, 2010 at 10:14 AM, Vivek Goyal <vgoyal@redhat.com> wrote: > > @@ -3420,7 +3453,10 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) > > * the queue. > > */ > > if (cfq_should_wait_busy(cfqd, cfqq)) { > > - cfqq->slice_end = jiffies + cfqd->cfq_slice_idle; > > + unsigned long extend_sl = cfqd->cfq_slice_idle; > > + if (!cfqd->cfq_slice_idle) > > + extend_sl = cfqd->cfq_group_idle; > > + cfqq->slice_end = jiffies + extend_sl; > > cfq_mark_cfqq_wait_busy(cfqq); > > cfq_log_cfqq(cfqd, cfqq, "will busy wait"); > > } > > Vivek, I haven't looked at this particular code snippet for some time. > Can you tell me why we add the slice_idle (or w/ your change > extend_sl) to slice_end instead of arming the idle timer with that > amount of time?
Divyesh,
With wait busy we do arm the slice time also. wait busy is just saying that extend the slice a bit so that we do arm the timer and select_queue() does not expire the queue right away.
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