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From: Keith Busch <[email protected]>
To: Christoph Hellwig <[email protected]>
Cc: Jens Axboe <[email protected]>,
	"Michael S. Tsirkin" <[email protected]>,
	Jason Wang <[email protected]>,
	Sagi Grimberg <[email protected]>,
	Pavel Begunkov <[email protected]>,
	[email protected], [email protected],
	[email protected], [email protected]
Subject: Re: [PATCH 1/6] nvme-pci: reverse request order in nvme_queue_rqs
Date: Wed, 13 Nov 2024 12:10:49 -0700	[thread overview]
Message-ID: <ZzT5ubYLImyhNrCp@kbusch-mbp> (raw)
In-Reply-To: <[email protected]>

On Wed, Nov 13, 2024 at 04:20:41PM +0100, Christoph Hellwig wrote:
> blk_mq_flush_plug_list submits requests in the reverse order that they
> were submitted, which leads to a rather suboptimal I/O pattern especially
> in rotational devices.  Fix this by rewriting nvme_queue_rqs so that it
> always pops the requests from the passed in request list, and then adds
> them to the head of a local submit list.  This actually simplifies the
> code a bit as it removes the complicated list splicing, at the cost of
> extra updates of the rq_next pointer.  As that should be cache hot
> anyway it should be an easy price to pay.

Looks good.

Reviewed-by: Keith Busch <[email protected]>

  reply	other threads:[~2024-11-13 19:10 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-13 15:20 don't reorder requests passed to ->queue_rqs Christoph Hellwig
2024-11-13 15:20 ` [PATCH 1/6] nvme-pci: reverse request order in nvme_queue_rqs Christoph Hellwig
2024-11-13 19:10   ` Keith Busch [this message]
2024-11-13 15:20 ` [PATCH 2/6] virtio_blk: reverse request order in virtio_queue_rqs Christoph Hellwig
2024-11-13 19:03   ` Keith Busch
2024-11-13 19:05     ` Jens Axboe
2024-11-13 23:25   ` Michael S. Tsirkin
2024-11-13 15:20 ` [PATCH 3/6] block: remove rq_list_move Christoph Hellwig
2024-11-13 15:20 ` [PATCH 4/6] block: add a rq_list type Christoph Hellwig
2024-11-14 20:11   ` Nathan Chancellor
2024-11-15  9:10     ` Christoph Hellwig
2024-11-15 12:49     ` Jens Axboe
2024-11-15 19:38       ` Jens Axboe
2024-11-16  0:56         ` Nathan Chancellor
2024-11-13 15:20 ` [PATCH 5/6] block: don't reorder requests in blk_add_rq_to_plug Christoph Hellwig
2024-11-13 15:20 ` [PATCH 6/6] block: don't reorder requests in blk_mq_add_to_batch Christoph Hellwig
2024-11-13 18:33 ` don't reorder requests passed to ->queue_rqs Bart Van Assche
2024-11-13 18:39   ` Jens Axboe
2024-11-13 18:46 ` Jens Axboe
2024-11-13 20:36 ` Chaitanya Kulkarni
2024-11-13 20:51   ` Jens Axboe
2024-11-13 22:23     ` Chaitanya Kulkarni
2024-11-13 22:27       ` Jens Axboe
2024-11-14  4:16     ` Christoph Hellwig
2024-11-14 15:14       ` Jens Axboe
2024-11-18 15:23         ` Christoph Hellwig

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