Proposal for adding O_DIRECT support into JDK 9

Lu, Yingqi at
Sat Aug 27 16:00:38 UTC 2016

The workload we have uses fis/fos/raf, that is why we started here following the example of other file open flags. We can surely look into filechannel extended open options to see if it fits better there. 


Sent from my iPhone

> On Aug 27, 2016, at 12:43 AM, Alan Bateman <Alan.Bateman at> wrote:
>> On 26/08/2016 23:31, Lu, Yingqi wrote:
>> Dear All,
>> This is a proposal for adding O_DIRECT support into JDK 9 for reading/writing from/to a file on Linux platform. O_DIRECT is a file-open flag to pass to OPEN (2). It tries to minimize cache effects of the I/O to and from this file. File I/O is done directly to/from user-space buffers. Please refer to for more details.
> FIS/FOS/RAF doesn't seem the right place for this. Have you looked at using extended open options with FileChannel instead?
> -Alan

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