Messages in this thread Patch in this message | | | Date | Thu, 16 Jun 2005 12:47:06 +0900 | From | Tejun Heo <> | Subject | [PATCH linux-2.6.12-rc6-mm1] blk: elevator unplug thresh hanlding fix |
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Hello, Jens. Hello, Andrew.
This patch fixes q->unplug_thresh condition check in __elv_add_request(). rq.count[READ] + rq.count[WRITE] can increase more than one if another thread has allocated a request after the current request is allocated or in_flight could have changed resulting in larger-than-one change of nrq, thus breaking the threshold mechanism.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Index: blk-fixes/drivers/block/elevator.c =================================================================== --- blk-fixes.orig/drivers/block/elevator.c 2005-06-16 12:16:59.000000000 +0900 +++ blk-fixes/drivers/block/elevator.c 2005-06-16 12:17:03.000000000 +0900 @@ -352,7 +352,7 @@ void __elv_add_request(request_queue_t * int nrq = q->rq.count[READ] + q->rq.count[WRITE] - q->in_flight; - if (nrq == q->unplug_thresh) + if (nrq >= q->unplug_thresh) __generic_unplug_device(q); } } else - 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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