Proposal for adding O_DIRECT support into JDK 9

[Lu, Yingqi]

Hi All,

We are checking if you get any extra feedback on the DirectIO patch listed below. 

Just a FYI. I will be on vacation from Nov. 30th to Dec. 8th and will be back to office on Dec. 9th. 

Thanks,
Lucy

>-----Original Message-----
>From: Lu, Yingqi
>Sent: Monday, November 21, 2016 11:51 AM
>To: Lu, Yingqi <yingqi.lu at intel.com>; Philippe Marschall
><philippe.marschall at gmail.com>; nio-dev at openjdk.java.net; Alan Bateman
><Alan.Bateman at oracle.com>; Brian Burkhalter <brian.burkhalter at oracle.com>
>Cc: David Holmes <david.holmes at oracle.com>; Kaczmarek, Eric
><eric.kaczmarek at intel.com>; Thomas Stüfe <thomas.stuefe at gmail.com>;
>Kharbas, Kishor <kishor.kharbas at intel.com>
>Subject: RE: Proposal for adding O_DIRECT support into JDK 9
>
>Hi All,
>
>Just want to check if there is any other feedback on the most recent DirectIO
>patch which is available at
>http://cr.openjdk.java.net/~kkharbas/8164900/webrev.04/
>
>Thanks,
>Lucy
>
>>-----Original Message-----
>>From: nio-dev [mailto:nio-dev-bounces at openjdk.java.net] On Behalf Of
>>Lu, Yingqi
>>Sent: Thursday, November 17, 2016 9:06 AM
>>To: Philippe Marschall <philippe.marschall at gmail.com>; nio-
>>dev at openjdk.java.net
>>Cc: David Holmes <david.holmes at oracle.com>; Kaczmarek, Eric
>><eric.kaczmarek at intel.com>; Thomas Stüfe <thomas.stuefe at gmail.com>;
>>Kharbas, Kishor <kishor.kharbas at intel.com>
>>Subject: RE: Proposal for adding O_DIRECT support into JDK 9
>>
>>Hi Philippe,
>>
>>Thank you very much for your feedback. We can certainly change
>>FileStore.getBlockSize to default method. We will make this
>>modification into our next version of the patch.
>>
>>All,
>>
>>Besides this change, do you have any other feedback and comments?
>>
>>Thanks,
>>Lucy
>>
>>>-----Original Message-----
>>>From: Philippe Marschall [mailto:philippe.marschall at gmail.com]
>>>Sent: Thursday, November 17, 2016 6:02 AM
>>>To: nio-dev at openjdk.java.net
>>>Cc: Alan Bateman <Alan.Bateman at oracle.com>; Lu, Yingqi
>>><yingqi.lu at intel.com>; Kharbas, Kishor <kishor.kharbas at intel.com>;
>>>David Holmes <david.holmes at oracle.com>; Thomas Stüfe
>>><thomas.stuefe at gmail.com>; Kaczmarek, Eric <eric.kaczmarek at intel.com>
>>>Subject: Re: Proposal for adding O_DIRECT support into JDK 9
>>>
>>>Hi
>>>
>>>I'm just a lurker so excuse me when overstep some boundaries here.
>>>Assuming FileStore#getBlockSize stays:
>>>- Could that be changed into a default method? That would be a help
>>>for any file system implementer (eg myself) and would also simplify
>>>JrtFileStore and ZipFileStore.
>>>- Could the Javadoc be updated to state that throwing
>>>UnsupportedOperationException is valid?
>>>
>>>Cheers
>>>Philippe
>>>
>>>On Wed, Nov 16, 2016 at 11:14 PM, Lu, Yingqi <yingqi.lu at intel.com> wrote:
>>>> Hi All,
>>>>
>>>>
>>>>
>>>> Our most recent version of our DirectIO patch is available at
>>>> http://cr.openjdk.java.net/~kkharbas/8164900/webrev.04/
>>>>
>>>> In this version, we have modified the following items:
>>>>
>>>> 1.       Remove ByteBuffer.allocateDirectAligned() and
>>>> ByteBuffer.isAligned(). Instead, using existing APIs
>>>> alignmentOffset() and
>>>> alignedSlice()
>>>>
>>>> 2.       Use Block Size as the alignment value instead of OS page size
>>>>
>>>> 3.       Create a function named getBlockSize from FileStore class
>>>>
>>>> 4.       Implement DirectIO for Windows
>>>>
>>>> 5.       JTreg test passed for Windows, Linux and OS X with regarding to the
>>>> DirectIO changes we made
>>>>
>>>>
>>>>
>>>> Please let us know your comments and feedback. Thank you very much
>>>> for your consideration!
>>>>
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> Lucy
>>>>
>>>>
>>>>
>>>> From: nio-dev [mailto:nio-dev-bounces at openjdk.java.net] On Behalf Of
>>>> Lu, Yingqi
>>>> Sent: Sunday, November 06, 2016 9:37 AM
>>>> To: Alan Bateman <Alan.Bateman at oracle.com>
>>>> Cc: Kharbas, Kishor <kishor.kharbas at intel.com>; David Holmes
>>>> <david.holmes at oracle.com>; core-libs-dev at openjdk.java.net;
>>>> nio-dev at openjdk.java.net; Thomas Stüfe <thomas.stuefe at gmail.com>;
>>>> Kaczmarek, Eric <eric.kaczmarek at intel.com>
>>>> Subject: Re: Proposal for adding O_DIRECT support into JDK 9
>>>>
>>>>
>>>>
>>>> Hi Alan,
>>>>
>>>>
>>>>
>>>> Thank you very much for your suggestion. FileStore is a better home
>>>> for the alignment value. We will use It in our next version of the
>>>> patch and update here for review soon.
>>>>
>>>> Thanks,
>>>>
>>>> Lucy
>>>>
>>>> Sent from my iPhone
>>>>
>>>> On Nov 6, 2016, at 9:04 AM, Alan Bateman <Alan.Bateman at oracle.com>
>>>wrote:
>>>>
>>>> On 06/11/2016 15:51, Lu, Yingqi wrote:
>>>>
>>>> Another approach might be use ioctl to get the block size and use
>>>> that as the alignment value. I think ioctl is available on UNIX
>>>> based OSes (please chime in if I miss any OS here) and has a similar
>>>> call for Windows named DeviceIoControl. The request code of ioctl is
>>>> different from OS to OS, but we could address that in the native code.
>>>>
>>>>
>>>>
>>>> A possible approach (I think I mentioned this in one of the early
>>>> mails) is to have FileStore expose the block size that can be use to
>>>> align and size the buffer.
>>>>
>>>> -Alan