aboutsummaryrefslogtreecommitdiffstats
path: root/block
diff options
context:
space:
mode:
authorJeff Moyer <jmoyer@redhat.com>2009-04-21 07:25:04 +0200
committerJens Axboe <jens.axboe@oracle.com>2009-04-22 08:35:11 +0200
commit4d00aa47e2337dcfe2d8a7215dbde3765b507167 (patch)
tree069f0c202e6a3f3017b0a8b4320b31172bcc1071 /block
parentb759113499d6c7cb75fab04f56772579308bc0f8 (diff)
downloadmrst-s0i3-test-4d00aa47e2337dcfe2d8a7215dbde3765b507167.tar.gz
mrst-s0i3-test-4d00aa47e2337dcfe2d8a7215dbde3765b507167.tar.xz
mrst-s0i3-test-4d00aa47e2337dcfe2d8a7215dbde3765b507167.zip
cfq-iosched: make seek_mean converge more quickly
Right now, depending on the first sector to which a process issues I/O, the seek time may start out way out of whack. So make sure we start with 0 sectors in seek, instead of the offset of the first request issued. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block')
-rw-r--r--block/cfq-iosched.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 0d3b70de3d8..0eb4aff9df6 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1908,7 +1908,9 @@ cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic,
sector_t sdist;
u64 total;
- if (cic->last_request_pos < rq->sector)
+ if (!cic->last_request_pos)
+ sdist = 0;
+ else if (cic->last_request_pos < rq->sector)
sdist = rq->sector - cic->last_request_pos;
else
sdist = cic->last_request_pos - rq->sector;