[ofiwg] fork support and MR cache

[Gal Pressman]

On 12/10/2020 19:51, Gal Pressman wrote:
>> On Thu, Oct 08, 2020 at 07:28:50PM +0000, Hefty, Sean wrote:
>>>> Please don't recode the kernel interface outside rdma-core, that stuff
>>>> is hard to do right.
>>>
>>> I'm was referring to calling:
>>>
>>> mr->context->ops.reg_mr(...)
>>>
>>> instead of indirectly through ibv_reg_mr().
>>
>> I deleted those function pointers from the public header a long time
>> ago. It was leaking internal ABI.
>>
>>> I'm actually fine disabling the cache if fork is enabled.  But how can that be detected?
>>
>> If you wan to propose an verbs API to show if the fork support MADV
>> stuff has been enabled that seems reasonable to me.
> 
> When you say DONTFORK will be obsolete I assume you refer to:
> https://lore.kernel.org/lkml/20200925222600.6832-1-peterx@redhat.com/
> 
> Right?
> 
> How will userspace rdma-core know whether DONTFORK is needed or not? Are there
> any RDMA kernel changes I'm missing?

I think my message got lost, sending again.