Messages in this thread Patch in this message | | | Date | Tue, 6 Nov 2007 23:05:10 +0300 | From | Oleg Nesterov <> | Subject | [PATCH] cfq: fix IOPRIO_CLASS_IDLE delays |
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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>
--- cfq/block/cfq-iosched.c~ 2007-08-09 19:59:26.000000000 +0400 +++ cfq/block/cfq-iosched.c 2007-11-06 22:39:08.000000000 +0300 @@ -2122,6 +2122,7 @@ static void *cfq_init_queue(struct reque INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); + cfqd->last_end_request = jiffies; cfqd->cfq_quantum = cfq_quantum; cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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