Messages in this thread | | | From | Logan Gunthorpe <> | Date | Mon, 5 Dec 2016 12:27:20 -0700 | Subject | Re: Enabling peer to peer device transactions for PCIe devices |
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On 05/12/16 12:14 PM, Jason Gunthorpe wrote: > But CMB sounds much more like the GPU case where there is a > specialized allocator handing out the BAR to consumers, so I'm not > sure a general purpose chardev makes a lot of sense?
I don't think it will ever need to be as complicated as the GPU case. There will probably only ever be a relatively small amount of memory behind the CMB and really the only users are those doing P2P work. Thus the specialized allocator could be pretty simple and I expect it would be fine to just return -ENOMEM if there is not enough memory.
Also, if it was implemented this way, if there was a need to make the allocator more complicated it could easily be added later as the userspace interface is just mmap to obtain a buffer.
Logan
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