[dm-devel] [PATCH 05/10] block: remove per-queue plugging
hch at infradead.org
hch at infradead.org
Tue Apr 12 16:44:17 UTC 2011
On Tue, Apr 12, 2011 at 02:58:46PM +0200, Jens Axboe wrote:
> Supposedly it's faster to do it inline rather than punt the dispatch.
> But that may actually not be true, if you have multiple plugs going (and
> thus multiple contenders for the queue lock on dispatch). So lets play
> it safe and punt to kblockd, we can always revisit this later.
Note that this can be optimized further by adding a new helper that just
queues up work on kblockd without taking the queue lock, e.g. adding a
new
void blk_run_queue_async(struct request_queue *q)
{
if (likely(!blk_queue_stopped(q)))
queue_delayed_work(kblockd_workqueue, &q->delay_work, 0);
}
And replacing all
__blk_run_queue(q, true);
callers with that, at which point they won't need the queuelock any
more.
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