tree 3b0bcb433294bb144b778ae97296ad4d8626ad47
parent fadad878cc0640cc9cd5569998bf54b693f7b38b
author Jens Axboe <jens.axboe@oracle.com> 1201516695 +0100
committer Jens Axboe <jens.axboe@oracle.com> 1201516695 +0100

cfq-iosched: relax IOPRIO_CLASS_IDLE restrictions

Currently you must be root to set idle io prio class on a process. This
is due to the fact that the idle class is implemented as a true idle
class, meaning that it will not make progress if someone else is
requesting disk access. Unfortunately this means that it opens DOS
opportunities by locking down file system resources, hence it is root
only at the moment.

This patch relaxes the idle class a little, by removing the truly idle
part (which entals a grace period with associated timer). The
modifications make the idle class as close to zero impact as can be done
while still guarenteeing progress. This means we can relax the root only
criteria as well.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>