From: "Christian König" <ckoenig.leichtzumerken@gmail.com>
To: Jason Gunthorpe <jgg@ziepe.ca>, Oded Gabbay <oded.gabbay@gmail.com>
Cc: "Gal Pressman" <galpress@amazon.com>,
sleybo@amazon.com, linux-rdma <linux-rdma@vger.kernel.org>,
"Oded Gabbay" <ogabbay@kernel.org>,
"Christoph Hellwig" <hch@lst.de>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
"Christian König" <christian.koenig@amd.com>,
"moderated list:DMA BUFFER SHARING FRAMEWORK"
<linaro-mm-sig@lists.linaro.org>,
"Doug Ledford" <dledford@redhat.com>,
"Tomer Tayar" <ttayar@habana.ai>,
"amd-gfx list" <amd-gfx@lists.freedesktop.org>,
"Greg KH" <gregkh@linuxfoundation.org>,
"Alex Deucher" <alexander.deucher@amd.com>,
"Leon Romanovsky" <leonro@nvidia.com>,
"open list:DMA BUFFER SHARING FRAMEWORK"
<linux-media@vger.kernel.org>
Subject: Re: [Linaro-mm-sig] [PATCH v3 1/2] habanalabs: define uAPI to export FD for DMA-BUF
Date: Tue, 22 Jun 2021 08:37:15 +0200 [thread overview]
Message-ID: <d358c740-fd3a-9ecd-7001-676e2cb44ec9@gmail.com> (raw)
In-Reply-To: <20210621232912.GK1096940@ziepe.ca>
Am 22.06.21 um 01:29 schrieb Jason Gunthorpe:
> On Mon, Jun 21, 2021 at 10:24:16PM +0300, Oded Gabbay wrote:
>
>> Another thing I want to emphasize is that we are doing p2p only
>> through the export/import of the FD. We do *not* allow the user to
>> mmap the dma-buf as we do not support direct IO. So there is no access
>> to these pages through the userspace.
> Arguably mmaping the memory is a better choice, and is the direction
> that Logan's series goes in. Here the use of DMABUF was specifically
> designed to allow hitless revokation of the memory, which this isn't
> even using.
The major problem with this approach is that DMA-buf is also used for
memory which isn't CPU accessible.
That was one of the reasons we didn't even considered using the mapping
memory approach for GPUs.
Regards,
Christian.
>
> So you are taking the hit of very limited hardware support and reduced
> performance just to squeeze into DMABUF..
>
> Jason
> _______________________________________________
> Linaro-mm-sig mailing list
> Linaro-mm-sig@lists.linaro.org
> https://lists.linaro.org/mailman/listinfo/linaro-mm-sig
next prev parent reply other threads:[~2021-06-22 6:37 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210618123615.11456-1-ogabbay@kernel.org>
2021-06-21 12:28 ` [PATCH v3 1/2] habanalabs: define uAPI to export FD for DMA-BUF Daniel Vetter
2021-06-21 13:02 ` Greg KH
2021-06-21 14:12 ` Jason Gunthorpe
2021-06-21 16:26 ` Oded Gabbay
2021-06-21 17:55 ` Jason Gunthorpe
2021-06-21 18:27 ` Daniel Vetter
2021-06-21 19:24 ` Oded Gabbay
2021-06-21 23:29 ` Jason Gunthorpe
2021-06-22 6:37 ` Christian König [this message]
2021-06-22 8:42 ` [Linaro-mm-sig] " Oded Gabbay
2021-06-22 12:01 ` Jason Gunthorpe
2021-06-22 12:04 ` Oded Gabbay
2021-06-22 12:15 ` Jason Gunthorpe
2021-06-22 13:12 ` Oded Gabbay
2021-06-22 15:11 ` Jason Gunthorpe
2021-06-22 15:24 ` Christian König
2021-06-22 15:28 ` Jason Gunthorpe
2021-06-22 15:31 ` Oded Gabbay
2021-06-22 15:31 ` Christian König
2021-06-22 15:40 ` Oded Gabbay
2021-06-22 15:49 ` Christian König
2021-06-22 15:24 ` Oded Gabbay
2021-06-22 15:34 ` Jason Gunthorpe
2021-06-22 12:23 ` Christian König
2021-06-22 15:23 ` Jason Gunthorpe
2021-06-22 15:29 ` Christian König
2021-06-22 15:40 ` Jason Gunthorpe
2021-06-22 15:48 ` Christian König
2021-06-22 16:05 ` Jason Gunthorpe
2021-06-23 8:57 ` Christian König
2021-06-23 9:14 ` Oded Gabbay
2021-06-23 18:24 ` Jason Gunthorpe
2021-06-23 18:43 ` Oded Gabbay
2021-06-23 18:50 ` Jason Gunthorpe
2021-06-23 19:00 ` Oded Gabbay
2021-06-23 19:34 ` Jason Gunthorpe
2021-06-23 19:39 ` Oded Gabbay
2021-06-24 0:45 ` Jason Gunthorpe
2021-06-24 5:40 ` Christoph Hellwig
2021-06-24 5:34 ` Christoph Hellwig
2021-06-24 8:07 ` Christian König
2021-06-24 8:12 ` Christoph Hellwig
2021-06-24 9:52 ` Christian König
2021-06-24 13:22 ` Christoph Hellwig
2021-06-22 16:50 ` Felix Kuehling
2021-06-21 14:20 ` Daniel Vetter
2021-06-21 14:49 ` Jason Gunthorpe
2021-06-21 14:17 ` Jason Gunthorpe
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