Commit 3586e917 authored Nov 26, 2009 by Gui Jianfeng Committed by Jens Axboe Nov 26, 2009

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>

parent 32a87c01

block/cfq-iosched.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -600,10 +600,14 @@ cfq_find_next_rq(struct cfq_data cfqd, struct cfq_queue cfqq,
		static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
		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.
		*/
		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));
		}