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Date:   Wed, 12 Jul 2023 20:57:35 -0300
From:   Jason Gunthorpe <jgg@ziepe.ca>
To:     Mina Almasry <almasrymina@google.com>
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Subject: Re: Memory providers multiplexing (Was: [PATCH net-next v4 4/5]
 page_pool: remove PP_FLAG_PAGE_FRAG flag)
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On Wed, Jul 12, 2023 at 01:16:00PM -0700, Mina Almasry wrote:

> The proposal was that the uapi in step #1 allocates a region of GPU
> memory, and sets up a p2pdma provider for this region of memory.

Honestly that feels too hacky, which is why I've said a few times
you'd actually need to integrate p2p pages into a DRM driver properly.

> 2. The p2pdma semantics seem to be global to the pci device. I.e., 1
> GPU can export 1 p2pdma resource at a time (the way I'm reading the
> API).

All of this is just a reflection that you are trying to use it in a
wrong hacky way. The driver is supposed to create a p2p registration
for its entire BAR at startup. Not on demand and not in fragments.

Jason