From 3440c49f5c5ecb4f29b0544aa87da71888404f8f Mon Sep 17 00:00:00 2001
From: Divyesh Shah <dpshah@google.com>
Date: Fri, 9 Apr 2010 09:29:57 +0200
Subject: [PATCH] cfq-iosched: Fix the incorrect timeslice accounting with
 forced_dispatch

When CFQ dispatches requests forcefully due to a barrier or changing iosched,
it runs through all cfqq's dispatching requests and then expires each queue.
However, it does not activate a cfqq before flushing its IOs resulting in
using stale values for computing slice_used.
This patch fixes it by calling activate queue before flushing reuqests from
each queue.

This is useful mostly for barrier requests because when the iosched is changing
it really doesnt matter if we have incorrect accounting since we're going to
break down all structures anyway.

We also now expire the current timeslice before moving on with the dispatch
to accurately account slice used for that cfqq.

Signed-off-by: Divyesh Shah<dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---
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