On 10/17/12 01:38, Tejun Heo wrote:
/** + * __blk_run_queue_uncond - run a queue whether or not it has been stopped + * @q: The queue to run + * + * Description: + * Invoke request handling on a queue if there are any pending requests. + * May be used to restart request handling after a request has completed. + * This variant runs the queue whether or not the queue has been + * stopped. Must be called with the queue lock held and interrupts + * disabled. See also @blk_run_queue. + */ +void __blk_run_queue_uncond(struct request_queue *q) +{ + if (unlikely(blk_queue_dead(q))) + return; + + q->request_fn(q); +} + +/** * __blk_run_queue - run a single device queue * @q: The queue to run * @@ -305,7 +324,7 @@ void __blk_run_queue(struct request_queue *q) if (unlikely(blk_queue_stopped(q))) return; - q->request_fn(q); + __blk_run_queue_uncond(q);__blk_run_queue_uncond() is a cold path and I don't think adding a test there matters but I think it would be better if we avoid an extra branch if possible for __blk_run_queue(). Can't we merge blk_queue_stopped/dead() testing?
How about declaring the function __blk_run_queue_uncond() inline ? That should allow the compiler to combine the two tests into a single test.
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