From: Alex Deucher <alexdeucher@gmail.com>
To: John Hubbard <jhubbard@nvidia.com>
Cc: Leon Romanovsky <leon@kernel.org>,
linux-rdma <linux-rdma@vger.kernel.org>,
Maling list - DRI developers <dri-devel@lists.freedesktop.org>,
Jason Gunthorpe <jgg@ziepe.ca>,
Doug Ledford <dledford@redhat.com>,
Daniel Vetter <daniel.vetter@intel.com>,
Christian Koenig <christian.koenig@amd.com>,
Jianxin Xiong <jianxin.xiong@intel.com>
Subject: Re: [PATCH v16 0/4] RDMA: Add dma-buf support
Date: Thu, 4 Feb 2021 08:50:38 -0500 [thread overview]
Message-ID: <CADnq5_M2YuOv16E2DG6sCPtL=z5SDDrN+y7iwD_pHVc7Omyrmw@mail.gmail.com> (raw)
In-Reply-To: <5e4ac17d-1654-9abc-9a14-bda223d62866@nvidia.com>
On Thu, Feb 4, 2021 at 2:48 AM John Hubbard <jhubbard@nvidia.com> wrote:
>
> On 12/15/20 1:27 PM, Jianxin Xiong wrote:
> > This patch series adds dma-buf importer role to the RDMA driver in
> > attempt to support RDMA using device memory such as GPU VRAM. Dma-buf is
> > chosen for a few reasons: first, the API is relatively simple and allows
> > a lot of flexibility in implementing the buffer manipulation ops.
> > Second, it doesn't require page structure. Third, dma-buf is already
> > supported in many GPU drivers. However, we are aware that existing GPU
> > drivers don't allow pinning device memory via the dma-buf interface.
> > Pinning would simply cause the backing storage to migrate to system RAM.
> > True peer-to-peer access is only possible using dynamic attach, which
> > requires on-demand paging support from the NIC to work. For this reason,
> > this series only works with ODP capable NICs.
>
> Hi,
>
> Looking ahead to after this patchset is merged...
>
> Are there design thoughts out there, about the future of pinning to vidmem,
> for this? It would allow a huge group of older GPUs and NICs and such to
> do p2p with this approach, and it seems like a natural next step, right?
The argument is that vram is a scarce resource, but I don't know if
that is really the case these days. At this point, we often have as
much vram as system ram if not more.
Alex
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next prev parent reply other threads:[~2021-02-04 13:50 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-15 21:27 [PATCH v16 0/4] RDMA: Add dma-buf support Jianxin Xiong
2020-12-15 21:27 ` [PATCH v16 1/4] RDMA/umem: Support importing dma-buf as user memory region Jianxin Xiong
2020-12-15 21:27 ` [PATCH v16 2/4] RDMA/core: Add device method for registering dma-buf based " Jianxin Xiong
2020-12-15 21:27 ` [PATCH v16 3/4] RDMA/uverbs: Add uverbs command for dma-buf based MR registration Jianxin Xiong
2020-12-15 21:27 ` [PATCH v16 4/4] RDMA/mlx5: Support dma-buf based userspace memory region Jianxin Xiong
2021-01-11 15:24 ` [PATCH v16 0/4] RDMA: Add dma-buf support Xiong, Jianxin
2021-01-11 15:42 ` Jason Gunthorpe
2021-01-11 17:44 ` Xiong, Jianxin
2021-01-11 17:47 ` Alex Deucher
2021-01-11 17:55 ` Xiong, Jianxin
2021-01-12 12:49 ` Yishai Hadas
2021-01-12 18:11 ` Xiong, Jianxin
2021-01-21 16:59 ` Jason Gunthorpe
2021-02-04 7:48 ` John Hubbard
2021-02-04 13:50 ` Alex Deucher [this message]
2021-02-04 18:29 ` Jason Gunthorpe
2021-02-04 18:44 ` Alex Deucher
2021-02-04 19:00 ` John Hubbard
2021-02-05 15:39 ` Daniel Vetter
2021-02-05 15:43 ` Jason Gunthorpe
2021-02-05 15:53 ` Daniel Vetter
2021-02-05 16:00 ` Jason Gunthorpe
2021-02-05 16:06 ` Daniel Vetter
2021-02-05 20:24 ` John Hubbard
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