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    SubjectRe: [PATCH] cfq: fix IOPRIO_CLASS_IDLE delays
    On Tue, Nov 06 2007, Oleg Nesterov wrote:
    > 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.

    Another good catch, thanks Oleg!

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

    Hmm, where would it overflow?

    --
    Jens Axboe

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