Re: [RFC 0/8] Copy Offload with Peer-to-Peer PCI Memory

Logan Gunthorpe
2017-04-19T22:55:22Z

On 19/04/17 02:48 PM, Jason Gunthorpe wrote:
> On Wed, Apr 19, 2017 at 01:41:49PM -0600, Logan Gunthorpe wrote:
>
>>> But.. it could point to a GPU and the GPU struct device could have a
>>> proxy dma_ops like Dan pointed out.
>>
>> Seems a bit awkward to me that in order for the intended use case, you
>> have to proxy the dma_ops. I'd probably still suggest throwing a couple
>> ops for things like this in the dev_pagemap.
>
> Another option is adding a new 'struct completer_dma_ops *' to struct
> device for this use case.
>
> Seems like a waste to expand dev_pagemap when we only need a unique
> value per struct device?

I feel like expanding dev_pagemap has a much lower impact than expanding
struct device... dev_pagemap is only one instance per zone device region
so expanding it shouldn't be a huge issue. Expanding struct device means
every device struct in the system gets bigger.

Logan