From: Jason Gunthorpe <jgg@ziepe.ca>
To: Zhiping Zhang <zhipingz@meta.com>
Cc: Leon Romanovsky <leon@kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
linux-rdma@vger.kernel.org, linux-pci@vger.kernel.org,
netdev@vger.kernel.org, Keith Busch <kbusch@kernel.org>,
Yochai Cohen <yochai@nvidia.com>,
Yishai Hadas <yishaih@nvidia.com>,
Bjorn Helgaas <helgaas@kernel.org>
Subject: Re: [RFC 0/2] Retrieve tph from dmabuf for PCIe P2P memory access
Date: Mon, 9 Feb 2026 14:13:03 -0400 [thread overview]
Message-ID: <20260209181303.GB943673@ziepe.ca> (raw)
In-Reply-To: <20260209175317.1713406-1-zhipingz@meta.com>
On Mon, Feb 09, 2026 at 09:53:10AM -0800, Zhiping Zhang wrote:
> Currently, the steering tag can be used for a CPU on the motherboard; the
> ACPI check is in place to query and obtain the supported tph settings. Here
> we intend to use the tph info to improve RDMA NIC memory access on a vfio-based
> accelerator device via PCIe peer-to-peer. When an applicantion register a
> RDMA memory region with DMABUF for the RDMA NIC to access the device memory,
> the tph associated with the memory region can be retrieved and used to set the
> steering tag / process hint (ph). The tph contains additional instructions
> or hints to the GPU or accelerator device for advanced memory operations,
> such as, read cache selection.
>
> Note this RFC is for the discussion on the direction and is not intended to be
> a complete implementation. Once the direction is agreed on, we will work on the
> implementation or a real patch set.
you didn't cc the DRM people who really need to look at any changes to
the dmabuf contract.
Jason
next prev parent reply other threads:[~2026-02-09 18:13 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-09 17:53 [RFC 0/2] Retrieve tph from dmabuf for PCIe P2P memory access Zhiping Zhang
2026-02-09 17:53 ` [RFC 1/2] Vfio: add callback to get tph info for dmabuf Zhiping Zhang
2026-02-09 17:53 ` [RFC 2/2] RMDA MLX5: get tph for p2p access when registering dmabuf mr Zhiping Zhang
2026-02-09 18:13 ` Jason Gunthorpe [this message]
2026-02-09 23:28 ` [RFC 0/2] Retrieve tph from dmabuf for PCIe P2P memory access Zhiping Zhang
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