[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/6] xen-blkfront: avoid to use start/stop queue
On Wed, 2017-07-12 at 02:20 +0800, Ming Lei wrote: > This interfaces will be removed soon, so use quiesce and > unquiesce instead, which should be more safe. > > The only one usage will be removed in the following > congestion control patches. Hello Ming, The title of this patch is misleading since this patch does not touch the calls related to queue congestion (blk_mq_stop_hw_queue() and blk_mq_start_stopped_hw_queues()). I assume that you meant that this patch avoids that the xen-blkfront driver uses blk_mq_(start|stop)_hw_queues() (with queues in plural form)? Can you please reflect that in the subject of this and related patches? Additionally, it's probably a good idea that this is not just an interface change but that this kind of patches fix a (hard to trigger?) race condition. > static inline void kick_pending_request_queues_locked(struct > blkfront_ring_info *rinfo) > { > - if (!RING_FULL(&rinfo->ring)) > + if (!RING_FULL(&rinfo->ring)) { > blk_mq_start_stopped_hw_queues(rinfo->dev_info->rq, true); > + blk_mq_kick_requeue_list(rinfo->dev_info->rq); > + } > } > > static void kick_pending_request_queues(struct blkfront_ring_info *rinfo) > @@ -1225,7 +1227,8 @@ static void kick_pending_request_queues(struct > blkfront_ring_info *rinfo) > unsigned long flags; > > spin_lock_irqsave(&rinfo->ring_lock, flags); > - kick_pending_request_queues_locked(rinfo); > + if (!RING_FULL(&rinfo->ring)) > + blk_mq_run_hw_queues(rinfo->dev_info->rq, true); > spin_unlock_irqrestore(&rinfo->ring_lock, flags); > } Why do some kick_pending_request_queues_locked() kick the requeue list and why has the above kick_pending_request_queues_locked() call been converted into a blk_mq_run_hw_queues() call and thereby ignores the requeue list? Thanks, Bart. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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