Re: [PATCH net-next] net/smc: add support for netdevice in containers.

Dust Li
2023-09-26T12:09:10Z

On Tue, Sep 26, 2023 at 02:41:04PM +0300, Leon Romanovsky wrote:
>On Tue, Sep 26, 2023 at 01:14:04PM +0200, Alexandra Winter wrote:
>>
>>
>> On 26.09.23 12:48, Leon Romanovsky wrote:
>> > This patch made me wonder, why doesn't SMC use RDMA-CM like all other
>> > in-kernel ULPs which work over RDMA?
>> >
>> > Thanks
>>
>> The idea behind SMC is that it should look an feel to the applications
>> like TCP sockets. So for connection management it uses TCP over IP;
>> RDMA is just used for the data transfer.
>
>I think that it is not different from other ULPs. For example, RDS works
>over sockets and doesn't touch or reimplement GID management logic.

I think the difference is SMC socket need to be compatible with TCP
socket, so it need a tcp socket to fallback when something is not working.

If SMC works with rdmacm, it still need a fallback-to-tcp socket, and
the tcp connection has to be established for each SMC socket before the
SMC socket got established, that would make rdmacm meaningless.

Best regards,
Dust

>
>Thanks