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From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@kernel.dk>,
	io-uring@vger.kernel.org, linux-block@vger.kernel.org
Cc: Miklos Szeredi <mszeredi@redhat.com>,
	ZiyangZhang <ZiyangZhang@linux.alibaba.com>,
	Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>,
	Bernd Schubert <bschubert@ddn.com>,
	Pavel Begunkov <asml.silence@gmail.com>,
	ming.lei@redhat.com
Subject: Re: [PATCH V3 00/16] io_uring/ublk: add IORING_OP_FUSED_CMD
Date: Fri, 17 Mar 2023 16:14:03 +0800	[thread overview]
Message-ID: <ZBQhSzIhvZL+83nM@ovpn-8-18.pek2.redhat.com> (raw)
In-Reply-To: <20230314125727.1731233-1-ming.lei@redhat.com>

On Tue, Mar 14, 2023 at 08:57:11PM +0800, Ming Lei wrote:
> Hello,
> 
> Add IORING_OP_FUSED_CMD, it is one special URING_CMD, which has to
> be SQE128. The 1st SQE(master) is one 64byte URING_CMD, and the 2nd
> 64byte SQE(slave) is another normal 64byte OP. For any OP which needs
> to support slave OP, io_issue_defs[op].fused_slave needs to be set as 1,
> and its ->issue() can retrieve/import buffer from master request's
> fused_cmd_kbuf. The slave OP is actually submitted from kernel, part of
> this idea is from Xiaoguang's ublk ebpf patchset, but this patchset
> submits slave OP just like normal OP issued from userspace, that said,
> SQE order is kept, and batching handling is done too.
> 
> Please see detailed design in commit log of the 2th patch, and one big
> point is how to handle buffer ownership.
> 
> With this way, it is easy to support zero copy for ublk/fuse device.
> 
> Basically userspace can specify any sub-buffer of the ublk block request
> buffer from the fused command just by setting 'offset/len'
> in the slave SQE for running slave OP. This way is flexible to implement
> io mapping: mirror, stripped, ...
> 
> The 3th & 4th patches enable fused slave support for the following OPs:
> 
> 	OP_READ/OP_WRITE
> 	OP_SEND/OP_RECV/OP_SEND_ZC
> 
> The other ublk patches cleans ublk driver and implement fused command
> for supporting zero copy.
> 
> Follows userspace code:
> 
> https://github.com/ming1/ubdsrv/tree/fused-cmd-zc-v2
> 
> All three(loop, nbd and qcow2) ublk targets have supported zero copy by passing:
> 
> 	ublk add -t [loop|nbd|qcow2] -z .... 
> 
> Basic fs mount/kernel building and builtin test are done, and also not
> observe regression on xfstest test over ublk-loop with zero copy.
> 
> Also add liburing test case for covering fused command based on miniublk
> of blktest:
> 
> https://github.com/ming1/liburing/commits/fused_cmd_miniublk
> 
> Performance improvement is obvious on memory bandwidth
> related workloads, such as, 1~2X improvement on 64K/512K BS
> IO test on loop with ramfs backing file.
> 
> Any comments are welcome!
> 
> V3:
> 	- fix build warning reported by kernel test robot
> 	- drop patch for checking fused flags on existed drivers with
> 	  ->uring_command(), which isn't necessary, since we do not do that
>       when adding new ioctl or uring command
>     - inline io_init_rq() for core code, so just export io_init_slave_req
> 	- return result of failed slave request unconditionally since REQ_F_CQE_SKIP
> 	will be cleared
> 	- pass xfstest over ublk-loop

Hello Jens and Guys,

I have been working on io_uring zero copy support for ublk/fuse for a while, and
I appreciate you may share any thoughts on this patchset or approach?


Thanks,
Ming


  parent reply	other threads:[~2023-03-17  8:16 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-14 12:57 [PATCH V3 00/16] io_uring/ublk: add IORING_OP_FUSED_CMD Ming Lei
2023-03-14 12:57 ` [PATCH V3 01/16] io_uring: increase io_kiocb->flags into 64bit Ming Lei
2023-03-14 12:57 ` [PATCH V3 02/16] io_uring: add IORING_OP_FUSED_CMD Ming Lei
2023-03-18 14:31   ` Jens Axboe
2023-03-18 15:24     ` Ming Lei
2023-03-18 16:00       ` Jens Axboe
2023-03-18 16:13       ` Ming Lei
2023-03-14 12:57 ` [PATCH V3 03/16] io_uring: support OP_READ/OP_WRITE for fused slave request Ming Lei
2023-03-14 12:57 ` [PATCH V3 04/16] io_uring: support OP_SEND_ZC/OP_RECV " Ming Lei
2023-03-14 12:57 ` [PATCH V3 05/16] block: ublk_drv: mark device as LIVE before adding disk Ming Lei
2023-03-14 12:57 ` [PATCH V3 06/16] block: ublk_drv: add common exit handling Ming Lei
2023-03-14 12:57 ` [PATCH V3 07/16] block: ublk_drv: don't consider flush request in map/unmap io Ming Lei
2023-03-14 12:57 ` [PATCH V3 08/16] block: ublk_drv: add two helpers to clean up map/unmap request Ming Lei
2023-03-14 12:57 ` [PATCH V3 09/16] block: ublk_drv: clean up several helpers Ming Lei
2023-03-14 12:57 ` [PATCH V3 10/16] block: ublk_drv: cleanup 'struct ublk_map_data' Ming Lei
2023-03-14 12:57 ` [PATCH V3 11/16] block: ublk_drv: cleanup ublk_copy_user_pages Ming Lei
2023-03-14 12:57 ` [PATCH V3 12/16] block: ublk_drv: grab request reference when the request is handled by userspace Ming Lei
2023-03-14 12:57 ` [PATCH V3 13/16] block: ublk_drv: support to copy any part of request pages Ming Lei
2023-03-14 12:57 ` [PATCH V3 14/16] block: ublk_drv: add read()/write() support for ublk char device Ming Lei
2023-03-14 12:57 ` [PATCH V3 15/16] block: ublk_drv: don't check buffer in case of zero copy Ming Lei
2023-03-14 12:57 ` [PATCH V3 16/16] block: ublk_drv: apply io_uring FUSED_CMD for supporting " Ming Lei
2023-03-16  3:13 ` [PATCH V3 00/16] io_uring/ublk: add IORING_OP_FUSED_CMD Xiaoguang Wang
2023-03-16  3:56   ` Ming Lei
2023-03-18 16:23   ` Pavel Begunkov
2023-03-18 16:39     ` Ming Lei
2023-03-21  9:17     ` Ziyang Zhang
2023-03-27 16:04       ` Pavel Begunkov
2023-03-28  1:01         ` Ming Lei
2023-03-28 11:01           ` Pavel Begunkov
2023-03-28  0:53       ` Ming Lei
2023-03-29  6:57         ` Ziyang Zhang
2023-03-29  8:52           ` Ming Lei
2023-03-25 14:15     ` Ming Lei
2023-03-17  8:14 ` Ming Lei [this message]
2023-03-18 12:59   ` Jens Axboe
2023-03-18 13:35     ` Ming Lei
2023-03-18 14:36       ` Jens Axboe
2023-03-18 15:06         ` Ming Lei
2023-03-18 16:51       ` Pavel Begunkov
2023-03-18 23:42         ` Ming Lei
2023-03-19  0:17           ` Ming Lei
2023-03-28 10:55           ` Pavel Begunkov
2023-03-28 13:01             ` Ming Lei
2023-03-29  6:59               ` Ziyang Zhang
2023-03-29 10:43               ` Pavel Begunkov
2023-03-29 11:55                 ` Ming Lei
2023-03-18 16:09 ` Jens Axboe
2023-03-18 17:01   ` Ming Lei
2023-03-21 15:56 ` Ming Lei

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