[PATCH v3 3/3] nvmet-rdma: support 16K inline data

[swise@opengridcomputing.com (Steve Wise)]

On 5/30/2018 5:13 PM, Sagi Grimberg wrote:
>
>> Its ugly because registering an MR for the inline pages requires a
>> connected QP to use the REG_MR WR.
>
> No, why MR?
>
>> Maybe I'll just split the needed
>> pages across the remaining recv sge entries available?? IE if the device
>> supports 5 recv sges, then 4 can be used for inline, and thus 4
>> non-contiguous pages could be used.
>
> That's what I had in mind...
>
>> cxgb4, however, only support 4 recv
>> sges, so it would only support 12K of inline with this implementation.
>
> :(
>
>> And perhaps there are rdma devices with even fewer recv sges?
>>
>> Do you have any other idea on how to avoid higher-order allocations?
>
> Not really. I guess that we should be able to recv the user
> inline_data_size. So maybe it would be ok if the we'd do that only if
> we must?

I'll explore this idea.?? I also thought about just reducing the inline
data size based on the number of sges available.? But I think the inline
data size has already been advertised to the host side at the time the
target is allocating these pages. :(

Steve.