[PATCH 0/4] cfq-iosched: policy fixes

From: Corrado Zoccolo
Date: Tue Nov 24 2009 - 08:48:52 EST


Hi Jens,
I've collected some bugfixes to the for-2.6.33 branch.
Excluding the NCQ policy fix, that I'm resending with improved changelog,
the bugs were found by Vivek while investingating performance drops
or unfairness while testing cgroups. Nevertheless, those fixes have
general impact, so they should go in before cgroup code is merged:
* no-idle preemption logic was both under/over preempting.
it should preempt only if the active queue is idling due to
no-idle service tree empty
* seeky queues with large depth could steal too much bandwidth to
low depth ones, so they will be marked as idling, and have exclusive
access to disk for their time share
* the idling logic had some corner cases in which idling was not enabled,
even if it should have been, caused by rq_noidle and rq_in_driver checks.
Those were adjusted to better match the original intention.

Corrado
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/