Re: [Patch v8 12/12] RDMA/mana_ib: Add a driver for Microsoft Azure Network Adapter

Tom Talpey
2022-10-22T00:35:05Z

On 10/21/2022 6:55 PM, Long Li wrote:
>>> The upper 8 bits of an ib_mr remote token are reserved for use as a
>>> rotating key, this allows a consumer to more safely reuse an ib_mr
>>> without having to overallocate large region pools.
>>>
>>> Tom.
>>
>> Right, my point was that one cannot encode INT_MAX different MR
>> identifiers into 32 - 8 = 24 bits.
>>
>> Best,
>> Bernard.
>
> The hardware exposes the number of MRs that exceeds UINT32_MAX.
> There is no software stack limit from hardware perspective.
>
> In this case, maybe it's a good idea to set it to 0xFFFFFF. I'm making the change.

Actually, 2^24 MRs is enormous in itself. Does this driver
actually support that many? Without falling over?

Tom.