From: Jason Gunthorpe <jgg@ziepe.ca>
To: Gal Pressman <galpress@amazon.com>
Cc: "Daniel Vetter" <daniel@ffwll.ch>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Christian König" <christian.koenig@amd.com>,
"Doug Ledford" <dledford@redhat.com>,
"open list:DMA BUFFER SHARING FRAMEWORK"
<linux-media@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
linux-rdma <linux-rdma@vger.kernel.org>,
"Oded Gabbay" <ogabbay@habana.ai>,
"Tomer Tayar" <ttayar@habana.ai>,
"Yossi Leybovich" <sleybo@amazon.com>,
"Alexander Matushevsky" <matua@amazon.com>,
"Leon Romanovsky" <leonro@nvidia.com>,
"Jianxin Xiong" <jianxin.xiong@intel.com>,
"John Hubbard" <jhubbard@nvidia.com>
Subject: Re: [RFC] Make use of non-dynamic dmabuf in RDMA
Date: Fri, 20 Aug 2021 11:32:48 -0300 [thread overview]
Message-ID: <20210820143248.GX543798@ziepe.ca> (raw)
In-Reply-To: <0fc94ac0-2bb9-4835-62b8-ea14f85fe512@amazon.com>
On Fri, Aug 20, 2021 at 03:58:33PM +0300, Gal Pressman wrote:
> Though it would've been nicer if we could agree on a solution that could work
> for more than 1-2 RDMA devices, using the existing tools the RDMA subsystem has.
I don't think it can really be done, revoke is necessary, and isn't a
primitive we have today.
Revoke is sort of like rereg MR, but with a guaranteed no-change to
the lkey/rkey
Then there is the locking complexity of linking the mr creation and
destruction to the lifecycle of the pages, which is messy and maybe
not general. For instance mlx5 would call its revoke_mr, disconnect
the dmabuf then destroy the mkey - but this is only safe because mlx5
HW can handle concurrent revokes.
> That's why I tried to approach this by denying such attachments for non-ODP
> importers instead of exposing a "limited" dynamic importer.
That is fine if there is no revoke - once revoke exists we must have
driver and HW support.
Jason
next prev parent reply other threads:[~2021-08-20 14:32 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-18 7:43 [RFC] Make use of non-dynamic dmabuf in RDMA Gal Pressman
2021-08-18 8:00 ` Christian König
2021-08-18 8:37 ` Gal Pressman
2021-08-18 9:34 ` Daniel Vetter
2021-08-19 23:06 ` Jason Gunthorpe
2021-08-20 7:25 ` Daniel Vetter
2021-08-20 12:33 ` Jason Gunthorpe
2021-08-20 12:58 ` Gal Pressman
2021-08-20 14:32 ` Jason Gunthorpe [this message]
2021-08-21 9:16 ` Gal Pressman
2021-08-23 10:43 ` Christian König
2021-08-24 9:06 ` Gal Pressman
2021-08-24 9:32 ` Christian König
2021-08-24 17:27 ` John Hubbard
2021-08-24 17:32 ` Jason Gunthorpe
2021-08-24 17:35 ` John Hubbard
2021-08-24 19:15 ` Dave Airlie
2021-08-24 19:30 ` Jason Gunthorpe
2021-08-24 19:43 ` Alex Deucher
2021-08-24 20:00 ` Xiong, Jianxin
2021-08-25 6:17 ` Christian König
2021-08-25 6:47 ` John Hubbard
2021-08-25 12:18 ` Jason Gunthorpe
2021-08-25 12:27 ` Christian König
2021-08-25 12:38 ` Jason Gunthorpe
2021-08-25 13:51 ` Christian König
2021-08-25 14:47 ` Jason Gunthorpe
2021-08-25 15:14 ` Christian König
2021-08-25 15:49 ` Jason Gunthorpe
2021-08-25 16:02 ` Oded Gabbay
2021-09-01 11:20 ` Gal Pressman
2021-09-01 11:24 ` Christian König
2021-09-02 6:56 ` Gal Pressman
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