On May 5, 2015, at 11:44 AM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > On Fri, Mar 13, 2015 at 05:21:17PM -0400, Chuck Lever wrote: >> This is a series of client-side patches for NFS/RDMA. In preparation >> for increasing the transport credit limit and maximum rsize/wsize, >> I've re-factored the memory registration logic into separate files, >> invoked via a method API. > > Just curious if you ever though of moving this into the generic > rdma layer? Not really. The new files are really just shims that adapt the RPC/RDMA transport to memory registration verbs. There’s only a few hundred lines per registration mode, and it’s all fairly specific to RPC/RDMA. > I've been working on a rdma based storage driver recently, and the > various different memory registration methods are a complete pain in the > ass, and impossible to test in and ULD without havin access to all kinds > of different hardware. Agree that the test matrix grows exponentially in complexity and expense as more MR modes are introduced. We have strategies for managing this when there’s a community involved, but when there’s just one developer it’s a challenge. > And from I see we litterly dont use them much different from the generic > dma mapping API helpers (at a very high level) so it seems it should > be easy to move a slightly expanded version of your API to the core > code. IMO FRWR is the only registration mode that has legs for the long term, and is specifically designed for storage. If you are not working on a legacy piece of code that has to support older HCAs, why not stay with FRWR? -- Chuck Lever chuck[dot]lever[at]oracle[dot]com -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
