cfq: Make use of service count to estimate the rb_key offset

For the moment, different workload cfq queues are put into different
service trees. But CFQ still uses "busy_queues" to estimate rb_key
offset when inserting a cfq queue into a service tree. I think this
isn't appropriate, and it should make use of service tree count to do
this estimation. This patch is for for-2.6.33 branch.

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Gui Jianfeng 2009-11-26 09:14:11 +01:00 committed by Jens Axboe
parent 32a87c0114
commit 3586e917f2

View file

@ -600,11 +600,15 @@ cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
static unsigned long cfq_slice_offset(struct cfq_data *cfqd, static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
struct cfq_queue *cfqq) struct cfq_queue *cfqq)
{ {
struct cfq_rb_root *service_tree;
service_tree = service_tree_for(cfqq_prio(cfqq), cfqq_type(cfqq), cfqd);
/* /*
* just an approximation, should be ok. * just an approximation, should be ok.
*/ */
return (cfqd->busy_queues - 1) * (cfq_prio_slice(cfqd, 1, 0) - return service_tree->count * (cfq_prio_slice(cfqd, 1, 0) -
cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio));
} }
/* /*