Commit bf572256 authored by Jens Axboe's avatar Jens Axboe Committed by Jens Axboe

[PATCH] cfq-iosched: improve queue preemption

Don't touch the current queues, just make sure that the wanted queue
is selected next. Simplifies the logic.
Signed-off-by: default avatarJens Axboe <axboe@suse.de>
parent dc72ef4a
......@@ -1539,17 +1539,19 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
*/
static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
struct cfq_queue *__cfqq, *next;
list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list)
cfq_resort_rr_list(__cfqq, 1);
cfq_slice_expired(cfqd, 1);
if (!cfqq->slice_left)
cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2;
/*
* Put the new queue at the front of the of the current list,
* so we know that it will be selected next.
*/
BUG_ON(!cfq_cfqq_on_rr(cfqq));
list_move(&cfqq->cfq_list, &cfqd->cur_rr);
cfqq->slice_end = cfqq->slice_left + jiffies;
cfq_slice_expired(cfqd, 1);
__cfq_set_active_queue(cfqd, cfqq);
}
/*
......
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