From: Randy Dunlap <rdunlap@infradead.org>
To: Bagas Sanjaya <bagasdotme@gmail.com>, Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-doc@vger.kernel.org, linux-block@vger.kernel.org,
Christoph Hellwig <hch@lst.de>, Jonathan Corbet <corbet@lwn.net>,
"Richard W . M . Jones" <rjones@redhat.com>,
ZiyangZhang <ZiyangZhang@linux.alibaba.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Subject: Re: [PATCH] Docs: ublk: add ublk document
Date: Sun, 28 Aug 2022 08:17:02 -0700 [thread overview]
Message-ID: <e304cb66-4890-5770-fca3-156c3428bf3d@infradead.org> (raw)
In-Reply-To: <YwtiTr3E4b9c+Vcl@debian.me>
On 8/28/22 05:40, Bagas Sanjaya wrote:
> Zero copy
> ---------
>
> -Wrt. zero copy support, it is one generic requirement for nbd, fuse or
> -similar drivers, one problem Xiaoguang mentioned is that pages mapped to
> -userspace can't be remapped any more in kernel with existed mm interfaces,
> -and it can be involved when submitting direct IO to /dev/ublkb*. Also
> -Xiaoguang reported that big request may benefit from zero copy a lot,
> -such as >= 256KB IO.
> +Wrt. zero copy support, which is a generic requirement for nbd, fuse or
> +similar drivers, a problem Xiaoguang mentioned is that pages mapped to
> +userspace can't be remapped any more in kernel with existing mm interfaces.
> +This can occurs when destining direct IO to ``/dev/ublkb*``. Also
> +he reported that big requests (>= 256 KB IO) may benefit a lot from zero copy.
I suggest eliminating "Wrt." also.
--
~Randy
next prev parent reply other threads:[~2022-08-28 15:17 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-28 4:50 [PATCH] Docs: ublk: add ublk document Ming Lei
2022-08-28 12:40 ` Bagas Sanjaya
2022-08-28 15:17 ` Randy Dunlap [this message]
2022-08-30 8:53 ` Ming Lei
2022-08-28 15:09 ` Richard W.M. Jones
2022-08-29 3:58 ` Gao Xiang
2022-08-30 9:05 ` Ming Lei
2022-08-29 0:18 ` kernel test robot
2022-08-30 12:14 ` Bagas Sanjaya
2022-08-30 14:13 ` Ming Lei
2022-08-30 15:23 ` Stefan Hajnoczi
2022-08-31 6:31 ` Ziyang Zhang
2022-08-31 20:00 ` Stefan Hajnoczi
2022-09-01 1:34 ` Ming Lei
2022-09-01 2:47 ` Ziyang Zhang
2022-09-01 0:56 ` Ming Lei
2022-09-01 1:04 ` Jens Axboe
2022-09-01 1:35 ` Ming Lei
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