From: Oleg Nesterov <oleg@tv-sign.ru>
Date: Wed, 7 Nov 2007 08:46:13 +0000 (+0100)
Subject: cfq: fix IOPRIO_CLASS_IDLE delays
X-Git-Tag: v2.6.24-rc3~174^2~6
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b70c864d3ce706571d2f3cac1d35d4fba01d6072;p=pandora-kernel.git

cfq: fix IOPRIO_CLASS_IDLE delays

After the fresh boot:

	ionice -c3 -p $$
	echo cfq >> /sys/block/XXX/queue/scheduler
	dd if=/dev/XXX of=/dev/null bs=512 count=1

Now dd hangs in D state and the queue is completely stalled for approximately
INITIAL_JIFFIES + CFQ_IDLE_GRACE jiffies. This is because cfq_init_queue()
forgets to initialize cfq_data->last_end_request.

(I guess this patch is not complete, overflow is still possible)

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

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