tree 6ee855ce6e8b0eb8cb04d41579ac11cb25a92759
parent dfb3d72a9aa519672c9ae06f0d2f93eccb35482f
author Aaron Carroll <aaronc@gelato.unsw.edu.au> 1193737213 +0100
committer Jens Axboe <axboe@carl.home.kernel.dk> 1193989645 +0100

Deadline iosched: Fix batching fairness

After switching data directions, deadline always starts the next batch
from the lowest-sector request.  This gives excessive deadline expiries
and large latency and throughput disparity between high- and low-sector
requests; an order of magnitude in some tests.

This patch changes the batching behaviour so new batches start from the
request whose expiry is earliest.

Signed-off-by: Aaron Carroll <aaronc@gelato.unsw.edu.au>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>