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authorJeff Moyer <jmoyer@redhat.com>2009-04-21 01:31:56 -0400
committerJens Axboe <jens.axboe@oracle.com>2009-04-22 02:35:11 -0400
commit04dc6e71a28d4815bf9431efcafc107bb0ad2792 (patch)
treedd51f2491b984d9f8f571f2bdc6b51cadb8c686d /block/cfq-iosched.c
parent4d00aa47e2337dcfe2d8a7215dbde3765b507167 (diff)
cfq-iosched: use the default seek distance when there aren't enough seek samples
If the cfq io context doesn't have enough samples yet to provide a mean seek distance, then use the default threshold we have for seeky IO instead of defaulting to 0. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/cfq-iosched.c')
-rw-r--r--block/cfq-iosched.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 0eb4aff9df68..7e13f04b5ed4 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -947,14 +947,18 @@ static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
947 return cfqd->last_position - rq->sector; 947 return cfqd->last_position - rq->sector;
948} 948}
949 949
950#define CIC_SEEK_THR 8 * 1024
951#define CIC_SEEKY(cic) ((cic)->seek_mean > CIC_SEEK_THR)
952
950static inline int cfq_rq_close(struct cfq_data *cfqd, struct request *rq) 953static inline int cfq_rq_close(struct cfq_data *cfqd, struct request *rq)
951{ 954{
952 struct cfq_io_context *cic = cfqd->active_cic; 955 struct cfq_io_context *cic = cfqd->active_cic;
956 sector_t sdist = cic->seek_mean;
953 957
954 if (!sample_valid(cic->seek_samples)) 958 if (!sample_valid(cic->seek_samples))
955 return 0; 959 sdist = CIC_SEEK_THR;
956 960
957 return cfq_dist_from_last(cfqd, rq) <= cic->seek_mean; 961 return cfq_dist_from_last(cfqd, rq) <= sdist;
958} 962}
959 963
960static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, 964static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
@@ -1039,9 +1043,6 @@ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
1039 return cfqq; 1043 return cfqq;
1040} 1044}
1041 1045
1042
1043#define CIC_SEEKY(cic) ((cic)->seek_mean > (8 * 1024))
1044
1045static void cfq_arm_slice_timer(struct cfq_data *cfqd) 1046static void cfq_arm_slice_timer(struct cfq_data *cfqd)
1046{ 1047{
1047 struct cfq_queue *cfqq = cfqd->active_queue; 1048 struct cfq_queue *cfqq = cfqd->active_queue;