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authorJens Axboe <axboe@suse.de>2006-07-19 20:29:12 +0200
committerJens Axboe <axboe@nelson.home.kernel.dk>2006-09-30 20:29:41 +0200
commitbf57225670bcbeb357182d800736b4782cde7295 (patch)
treec86d71fefff36090fc5c2ea3694f95d0162cdc2c /block/cfq-iosched.c
parentdc72ef4ae35c2016fb594bcc85ce871376682174 (diff)
downloadlinux-2.6.34-ux500-bf57225670bcbeb357182d800736b4782cde7295.tar.gz
[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: Jens Axboe <axboe@suse.de>
Diffstat (limited to 'block/cfq-iosched.c')
-rw-r--r--block/cfq-iosched.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 9f684cc66bd..14110483595 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -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);
}
/*