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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: "Christian König" <christian.koenig@amd.com>,
	"Leon Romanovsky" <leon@kernel.org>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	"Doug Ledford" <dledford@redhat.com>,
	"Vetter, Daniel" <daniel.vetter@intel.com>,
	"Xiong, Jianxin" <jianxin.xiong@intel.com>
Subject: Re: [RFC PATCH v2 0/3] RDMA: add dma-buf support
Date: Fri, 3 Jul 2020 10:14:45 -0300
Message-ID: <20200703131445.GU25301@ziepe.ca> (raw)
In-Reply-To: <CAKMK7uGqABchpPLTm=vmabkwK3JJSzWTFWhfU+ywbwjw-HgSzw@mail.gmail.com>

On Fri, Jul 03, 2020 at 02:52:03PM +0200, Daniel Vetter wrote:

> So maybe I'm just totally confused about the rdma model. I thought:
> - you bind a pile of memory for various transactions, that might
> happen whenever. Kernel driver doesn't have much if any insight into
> when memory isn't needed anymore. I think in the rdma world that's
> called registering memory, but not sure.

Sure, but once registered the memory is able to be used at any moment with
no visibilty from the kernel.

Unlike GPU the transactions that trigger memory access do not go
through the kernel - so there is no ability to interrupt a command
flow and fiddle with mappings.

Jason

  reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-29 17:31 Jianxin Xiong
2020-06-29 17:31 ` [RFC PATCH v2 1/3] RDMA/umem: Support importing dma-buf as user memory region Jianxin Xiong
2020-06-30 19:04   ` Xiong, Jianxin
2020-06-29 17:31 ` [RFC PATCH v2 2/3] RDMA/core: Expand the driver method 'reg_user_mr' to support dma-buf Jianxin Xiong
2020-06-30 19:04   ` Xiong, Jianxin
2020-06-29 17:31 ` [RFC PATCH v2 3/3] RDMA/uverbs: Add uverbs command for dma-buf based MR registration Jianxin Xiong
2020-06-30 19:05   ` Xiong, Jianxin
2020-06-29 18:51 ` [RFC PATCH v2 0/3] RDMA: add dma-buf support Jason Gunthorpe
2020-06-30 17:21   ` Xiong, Jianxin
2020-06-30 17:34     ` Jason Gunthorpe
2020-06-30 18:46       ` Xiong, Jianxin
2020-06-30 19:17         ` Jason Gunthorpe
2020-06-30 20:08           ` Xiong, Jianxin
2020-07-02 12:27             ` Jason Gunthorpe
2020-07-01  9:03         ` Christian König
2020-07-01 12:07           ` Daniel Vetter
2020-07-01 12:14             ` Daniel Vetter
2020-07-01 12:39           ` Jason Gunthorpe
2020-07-01 12:55             ` Christian König
2020-07-01 15:42               ` Daniel Vetter
2020-07-01 17:15                 ` Jason Gunthorpe
2020-07-02 13:10                   ` Daniel Vetter
2020-07-02 13:29                     ` Jason Gunthorpe
2020-07-02 14:50                       ` Christian König
2020-07-02 18:15                         ` Daniel Vetter
2020-07-03 12:03                           ` Jason Gunthorpe
2020-07-03 12:52                             ` Daniel Vetter
2020-07-03 13:14                               ` Jason Gunthorpe [this message]
2020-07-03 13:21                                 ` Christian König
2020-07-07 21:58                                   ` Xiong, Jianxin
2020-07-08  9:38                                     ` Christian König
2020-07-08  9:49                                       ` Daniel Vetter
2020-07-08 14:20                                         ` Christian König
2020-07-08 14:33                                           ` Alex Deucher
2020-06-30 18:56 ` Xiong, Jianxin

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