Re: [PATCH 2/3] cfq-iosched: Implement a new tunable group_idle

[Divyesh Shah]

On Mon, Jul 19, 2010 at 10:14 AM, Vivek Goyal <vgoyal@xxxxxxxxxx> 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
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