2009-05-14 13:40:55

by Steve Wise

[permalink] [raw]
Subject: Re: [ofa-general] Re: [PATCH 2.6.30] xprtrdma: The frmr iova_start values are truncated by the nfs rdma client.

Or Gerlitz wrote:
>> Trond Myklebust wrote
>>> All I should need to know is that I can advertise either dma handles
>>> or kernel VAs
>
> Maybe its obvious to some people here, but may I ask why there's a
> need to post either dma address or kernel virtual address? is it
> application need? hardware (e.g IB vs iWARP vs vendor implementation)
> specific? or something else?
>
> Or.
>
>

The NFSRDMA transport uses Fast Register Memory Regions. In this
particular section of code, the NFSRDMA client is building a fastreg
work request to bind a page list to a fastreg mr. You can read about
this in the IBTA spec on memory management extensions, or in the RDMA
Verbs draft.


Steve.


2009-05-14 13:45:34

by Or Gerlitz

[permalink] [raw]
Subject: Re: [ofa-general] Re: [PATCH 2.6.30] xprtrdma: The frmr iova_start values are truncated by the nfs rdma client.

Steve Wise wrote:
> The NFSRDMA transport uses Fast Register Memory Regions. In this
> particular section of code, the NFSRDMA client is building a fastreg
> work request to bind a page list to a fastreg mr. You can read about
> this in the IBTA spec on memory management extensions, or in the RDMA Verbs draft.

Hi Steve,

I was aware for the context being fastreg work request. I was thinking
that the spec mandates either dma addr or kva on the iova but from your reply
I assume to be wrong, thanks.

Or.