Hi Tom- On Jul 20, 2015, at 4:34 PM, Tom Talpey <tom@xxxxxxxxxx> wrote: > On 7/20/2015 12:03 PM, Chuck Lever wrote: >> All HCA providers have an ib_get_dma_mr() verb. Thus >> rpcrdma_ia_open() will either grab the device's local_dma_key if one >> is available, or it will call ib_get_dma_mr() which is a 100% >> guaranteed fallback. > > I recall that in the past, some providers did not support mapping > all of the machine's potential physical memory with a single dma_mr. > If an rnic did/does not support 44-ish bits of length per region, > for example. The buffers affected by this change are small, so I’m confident that restriction would not be a problem here. What might break with such restricted hardware is ALLPHYSICAL on large-memory systems. ALLPHYSICAL does rely on a single DMA MR that covers all of the NFS client’s memory. That would be a problem both before and after this patch, as far as I can tell. > Have you verified that all current providers do in fact support the > necessary physical address range for this, and that the requirement > is stated in the verbs going forward? -- Chuck Lever -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
