adding rsockets support into JDK

[Lu, Yingqi]

I already discussed with Sean on this specific issue. He mentioned that even he can propose a fix to the kernel librdmacm module, it would take years to get into majority of the distros. I would recommend to emulate the behavior inside JDK and make use of it.

I will quickly draft a patch and send here for review.

Thanks,
Lucy

>-----Original Message-----
>From: Alan Bateman [mailto:Alan.Bateman at oracle.com]
>Sent: Monday, December 17, 2018 10:54 AM
>To: Lu, Yingqi <yingqi.lu at intel.com>; Chris Hegarty
><chris.hegarty at oracle.com>
>Cc: nio-dev at openjdk.java.net; Viswanathan, Sandhya
><sandhya.viswanathan at intel.com>; Aundhe, Shirish
><shirish.aundhe at intel.com>; Kaczmarek, Eric <eric.kaczmarek at intel.com>
>Subject: Re: adding rsockets support into JDK
>
>On 17/12/2018 18:18, Lu, Yingqi wrote:
>> Hi Alan,
>>
>> Thank you for your suggestion. I just want to confirm that you meant all the
>RDMA based socket channels and server socket channels will be created as
>non-blocking initially? Later, if application sets them to be blocking, we then
>do the emulation.
>>
>> If this is the case, do we need to specify it in the Javadoc since the tcp based
>channels are created to be blocking?
>>
>This doesn't impact anyone using the API, this is just about emulating blocking
>behavior with an rsocket that is non-blocking. The rational is to keep the
>native code as simple as possible so that the native methods are a single
>syscall rather than many. Whether we need this of course depends on
>whether the bug in the Linux RDMA library will be fixed or not. Maybe we
>need to see if Sean can help progress the bug there before spending time on
>this.
>
>-Alan