All of lore.kernel.org
 help / color / mirror / Atom feed
From: Shunsuke Mie <mie@igel.co.jp>
To: Leon Romanovsky <leon@kernel.org>
Cc: linux-rdma@vger.kernel.org, Takanari Hayama <taki@igel.co.jp>
Subject: Re: [RFC] RDMA with Continuous Memory Allocator
Date: Tue, 13 Jul 2021 15:57:53 +0900	[thread overview]
Message-ID: <CANXvt5pMnCeMjAH02LM0szoJz526DRMZ9wZMC4-v7s-e=N33iQ@mail.gmail.com> (raw)
In-Reply-To: <YO0iDpxD2pJYV3t+@unreal>

Hi Leon,
Thank you for your reply.

> Sorry for my question, but why do you need it?
I'd like to write data to the buffer, prepared by DRM (gpu) driver as
a frame buffer, using RDMA.
There is a similar project as follows.
https://www.openfabrics.org/wp-content/uploads/2020-workshop-presentations/303.-OFI-GPU-DMA-BUF-OFA2020v2.pdf
They prepare a mechanism to share a dmabuf fd between DRM driver and
RDMA driver, in order to update frame buffer using RDMA. I'm trying to
develop that in userland.

Some DRM drivers use CMA to allocate the buffer. I met the problem in
an environment that CMA used.

> From that I remember, CMA memory is used for the devices that doesn't
> support scatter-gather, while RDMA devices (umem) need SG.
Yes, the CMA memory is allocated for a device that doesn't support
scatter-gather.

Thanks,

  reply	other threads:[~2021-07-13  6:58 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-09 10:24 [RFC] RDMA with Continuous Memory Allocator Shunsuke Mie
2021-07-13  5:18 ` Leon Romanovsky
2021-07-13  6:57   ` Shunsuke Mie [this message]
2021-07-13  8:30     ` Leon Romanovsky

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CANXvt5pMnCeMjAH02LM0szoJz526DRMZ9wZMC4-v7s-e=N33iQ@mail.gmail.com' \
    --to=mie@igel.co.jp \
    --cc=leon@kernel.org \
    --cc=linux-rdma@vger.kernel.org \
    --cc=taki@igel.co.jp \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.