Commit 4d00aa47 authored Apr 21, 2009 by Jeff Moyer Committed by Jens Axboe Apr 22, 2009

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>

parent b7591134

block/cfq-iosched.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -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;