[ofa-general] rdma_listen() backlog

[Steve Wise]

Isaac Huang wrote:
> On Thu, Jul 09, 2009 at 11:25:59AM -0700, Sean Hefty wrote:
>   
>>> Maybe I've missed something, but the last time I checked it appeared
>>> to me that for kernel RDMA CM the 'backlog' parameter was not used at
>>> all unless for iWarp transport.
>>>       
>> It's not used for kernel IB connections.  Since connection requests are reported
>> through a callback, there's nothing to queue and it's unneeded.
>>     
>
> I see, thanks for the explanation. But then why would iWarp transport
> cares the 'backlog' while connection requests are also reported via a
> callback? iw_cm_listen() allocates resources based on 'backlog' and I
> saw this comment over it:
>
> @backlog: The maximum number of outstanding un-accepted inbound listen
>   requests to queue.
>
>   

The iWARP rnics also map this backlog to the tcp backlog used in 
listening for incoming tcp connections.