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Commit e9ce335d authored by Shaohua Li's avatar Shaohua Li Committed by Jens Axboe
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cfq-iosched: fix a kbuild regression 



Alex Shi reported a kbuild regression which is about 10% performance lost.
He bisected to this commit: 3dde36dd.
The reason is cfqq_close() can't find close cooperator. Restoring
cfq_rq_close()'s threshold to original value makes the regression go away.

Since for_preempt parameter isn't used anymore, this patch deletes it.

Reported-by: default avatarAlex Shi <alex.shi@intel.com>
Signed-off-by: default avatarShaohua Li <shaohua.li@intel.com>
Acked-by: default avatarCorrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 910ac735

block/cfq-iosched.c

+6 −5
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ static const int cfq_hist_divisor = 4; 
#define CFQ_SERVICE_SHIFT       12



#define CFQQ_SEEK_THR		(sector_t)(8 * 100)

#define CFQQ_CLOSE_THR		(sector_t)(8 * 1024)

#define CFQQ_SECT_THR_NONROT	(sector_t)(2 * 32)

#define CFQQ_SEEKY(cfqq)	(hweight32(cfqq->seek_history) > 32/8)
@@ -1660,9 +1661,9 @@ static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, 
}



static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq,

			       struct request *rq, bool for_preempt)

			       struct request *rq)

{

	return cfq_dist_from_last(cfqd, rq) <= CFQQ_SEEK_THR;

	return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR;

}



static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
@@ -1689,7 +1690,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, 
	 * will contain the closest sector.

	 */

	__cfqq = rb_entry(parent, struct cfq_queue, p_node);

	if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false))

	if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))

		return __cfqq;



	if (blk_rq_pos(__cfqq->next_rq) < sector)
@@ -1700,7 +1701,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, 
		return NULL;



	__cfqq = rb_entry(node, struct cfq_queue, p_node);

	if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false))

	if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))

		return __cfqq;



	return NULL;
@@ -3103,7 +3104,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, 
	 * if this request is as-good as one we would expect from the

	 * current cfqq, let it preempt

	 */

	if (cfq_rq_close(cfqd, cfqq, rq, true))

	if (cfq_rq_close(cfqd, cfqq, rq))

		return true;



	return false;