[ofa-general] Re: [PATCH for-2.6.27 1/2] RDMA/Core: Add local dma lkey support.
swise at opengridcomputing.com
Tue Jul 8 11:12:24 PDT 2008
Roland Dreier wrote:
> so I applied this, but now I'm starting to wonder about how ULPs would
> use this. As I understand things, this is really working around the
> fact that cxgb3's get_dma_mr() implementation is limited to 4G. But how
> can a ULP know if a given device has the 4G limitation? For every other
> device (modulo iw_nes's 1 TB limitation) get_dma_mr works fine for local
> DMA. Thoughts?
> - R.
RDS and NFSRDMA will use the local_dma_lkey if the device supports it.
If not, it will use a dma_mr with local access rights. So using the
local_dma_lkey is just an optimization to avoid allocating a
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