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| author | Jeff Moyer <jmoyer@redhat.com> | 2009-04-21 07:25:04 +0200 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2009-04-22 08:35:11 +0200 |
| commit | 4d00aa47e2337dcfe2d8a7215dbde3765b507167 (patch) | |
| tree | 069f0c202e6a3f3017b0a8b4320b31172bcc1071 /block/cfq-iosched.c | |
| parent | b759113499d6c7cb75fab04f56772579308bc0f8 (diff) | |
| download | linux-4d00aa47e2337dcfe2d8a7215dbde3765b507167.tar.gz | |
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/cfq-iosched.c')
| -rw-r--r-- | block/cfq-iosched.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 0d3b70de3d80..0eb4aff9df68 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; |