From: Ming Lei <ming.lei@redhat.com>
To: Pavel Begunkov <asml.silence@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>,
io-uring@vger.kernel.org, linux-block@vger.kernel.org,
Miklos Szeredi <mszeredi@redhat.com>,
ZiyangZhang <ZiyangZhang@linux.alibaba.com>,
Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>,
Bernd Schubert <bschubert@ddn.com>,
ming.lei@redhat.com
Subject: Re: [PATCH V2 00/17] io_uring/ublk: add IORING_OP_FUSED_CMD
Date: Wed, 8 Mar 2023 09:08:06 +0800 [thread overview]
Message-ID: <ZAff9usDuyXxIPt9@ovpn-8-16.pek2.redhat.com> (raw)
In-Reply-To: <7e05882f-9695-895d-5e83-61006e54c4b2@gmail.com>
On Tue, Mar 07, 2023 at 03:37:21PM +0000, Pavel Begunkov wrote:
> On 3/7/23 14:15, 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.
>
> From a quick look through patches it all looks a bit complicated
> and intrusive, all over generic hot paths. I think instead we
Really? The main change to generic hot paths are adding one 'true/false'
parameter to io_init_req(). For others, the change is just check on
req->flags or issue_flags, which is basically zero cost.
> should be able to use registered buffer table as intermediary and
> reuse splicing. Let me try it out
I will take a look at you patch, but last time, Linus has pointed out that
splice isn't one good way, in which buffer ownership transferring is one big
issue for writing data to page retrieved from pipe.
https://lore.kernel.org/linux-block/CAJfpeguQ3xn2-6svkkVXJ88tiVfcDd-eKi1evzzfvu305fMoyw@mail.gmail.com/
Thanks,
Ming
next prev parent reply other threads:[~2023-03-08 1:09 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-07 14:15 [PATCH V2 00/17] io_uring/ublk: add IORING_OP_FUSED_CMD Ming Lei
2023-03-07 14:15 ` [PATCH V2 01/17] io_uring: add IO_URING_F_FUSED and prepare for supporting OP_FUSED_CMD Ming Lei
2023-03-07 14:15 ` [PATCH V2 02/17] io_uring: increase io_kiocb->flags into 64bit Ming Lei
2023-03-07 14:15 ` [PATCH V2 03/17] io_uring: add IORING_OP_FUSED_CMD Ming Lei
2023-03-07 14:15 ` [PATCH V2 04/17] io_uring: support OP_READ/OP_WRITE for fused slave request Ming Lei
2023-03-07 14:15 ` [PATCH V2 05/17] io_uring: support OP_SEND_ZC/OP_RECV " Ming Lei
2023-03-09 7:46 ` kernel test robot
2023-03-09 17:22 ` kernel test robot
2023-03-07 14:15 ` [PATCH V2 06/17] block: ublk_drv: mark device as LIVE before adding disk Ming Lei
2023-03-08 3:48 ` Ziyang Zhang
2023-03-08 7:44 ` Ming Lei
2023-03-07 14:15 ` [PATCH V2 07/17] block: ublk_drv: add common exit handling Ming Lei
2023-03-14 17:15 ` kernel test robot
2023-03-07 14:15 ` [PATCH V2 08/17] block: ublk_drv: don't consider flush request in map/unmap io Ming Lei
2023-03-08 3:50 ` Ziyang Zhang
2023-03-07 14:15 ` [PATCH V2 09/17] block: ublk_drv: add two helpers to clean up map/unmap request Ming Lei
2023-03-09 3:12 ` Ziyang Zhang
2023-03-07 14:15 ` [PATCH V2 10/17] block: ublk_drv: clean up several helpers Ming Lei
2023-03-09 3:12 ` Ziyang Zhang
2023-03-07 14:15 ` [PATCH V2 11/17] block: ublk_drv: cleanup 'struct ublk_map_data' Ming Lei
2023-03-09 3:16 ` Ziyang Zhang
2023-03-07 14:15 ` [PATCH V2 12/17] block: ublk_drv: cleanup ublk_copy_user_pages Ming Lei
2023-03-07 23:57 ` kernel test robot
2023-03-15 7:05 ` Ziyang Zhang
2023-03-07 14:15 ` [PATCH V2 13/17] block: ublk_drv: grab request reference when the request is handled by userspace Ming Lei
2023-03-15 5:20 ` kernel test robot
2023-03-07 14:15 ` [PATCH V2 14/17] block: ublk_drv: support to copy any part of request pages Ming Lei
2023-03-07 14:15 ` [PATCH V2 15/17] block: ublk_drv: add read()/write() support for ublk char device Ming Lei
2023-03-07 14:15 ` [PATCH V2 16/17] block: ublk_drv: don't check buffer in case of zero copy Ming Lei
2023-03-07 14:15 ` [PATCH V2 17/17] block: ublk_drv: apply io_uring FUSED_CMD for supporting " Ming Lei
2023-03-07 15:37 ` [PATCH V2 00/17] io_uring/ublk: add IORING_OP_FUSED_CMD Pavel Begunkov
2023-03-07 17:17 ` Pavel Begunkov
2023-03-08 2:10 ` Ming Lei
2023-03-08 14:46 ` Pavel Begunkov
2023-03-08 16:17 ` Ming Lei
2023-03-08 16:54 ` Pavel Begunkov
2023-03-09 1:44 ` Ming Lei
2023-03-08 1:08 ` Ming Lei [this message]
2023-03-08 16:22 ` Pavel Begunkov
2023-03-09 2:05 ` Ming Lei
2023-03-15 7:08 ` Ziyang Zhang
2023-03-15 7:54 ` Ming Lei
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