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From: Ming Lei <ming.lei@redhat.com>
To: linux-block@vger.kernel.org, virtualization@lists.linux.dev,
	linux-nvme@lists.infradead.org
Cc: ming.lei@redhat.com
Subject: [Report] requests are submitted to hardware in reverse order from nvme/virtio-blk queue_rqs()
Date: Wed, 24 Jan 2024 19:59:54 +0800	[thread overview]
Message-ID: <ZbD7ups50ryrlJ/G@fedora> (raw)

Hello,

Requests are added to plug list in reverse order, and both virtio-blk
and nvme retrieves request from plug list in order, so finally requests
are submitted to hardware in reverse order via nvme_queue_rqs() or
virtio_queue_rqs, see:

	io_uring       submit_bio  vdb      6302096     4096
	io_uring       submit_bio  vdb     12235072     4096
	io_uring       submit_bio  vdb      7682280     4096
	io_uring       submit_bio  vdb     11912464     4096
	io_uring virtio_queue_rqs  vdb     11912464     4096
	io_uring virtio_queue_rqs  vdb      7682280     4096
	io_uring virtio_queue_rqs  vdb     12235072     4096
	io_uring virtio_queue_rqs  vdb      6302096     4096


May this reorder be one problem for virtio-blk and nvme-pci?


Thanks,
Ming


             reply	other threads:[~2024-01-24 12:00 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-24 11:59 Ming Lei [this message]
2024-01-24 15:41 ` [Report] requests are submitted to hardware in reverse order from nvme/virtio-blk queue_rqs() Keith Busch
2024-01-24 22:32   ` Damien Le Moal
2024-01-25  4:23     ` Ming Lei
2024-01-25 15:33 ` Jens Axboe
2024-01-26 14:10 ` Christoph Hellwig
2024-10-07 22:39   ` Bart Van Assche
2024-10-08 11:33     ` Christoph Hellwig

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