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

Long Li
2022-10-22T00:38:45Z

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

The hardware can support that much. I don't see this driver will enforce other
limitation on that.