Messages in this thread | | | From | Logan Gunthorpe <> | Date | Tue, 18 Apr 2017 17:03:59 -0600 | Subject | Re: [RFC 0/8] Copy Offload with Peer-to-Peer PCI Memory |
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On 18/04/17 04:24 PM, Jason Gunthorpe wrote: > Try and write a stacked map_sg function like you describe and you will > see how horrible it quickly becomes.
Yes, unfortunately, I have to agree with this statement completely.
> Since dma mapping is a performance path we must be careful not to > create intrinsic inefficiencies with otherwise nice layering :)
Yeah, I'm also personally thinking your proposal is the way to go as well. Dan's injected ops suggestion is interesting but I can't see how it solves the issue completely. Your proposal is the only one that seems to be complete to me. It just has a few minor pain points which I've already described but are likely manageable and less than the pain stacked dma_ops creates.
Logan
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