RFR (XS): 8165860: workgroup classes are missing volatile qualifiers for lock-free code

[Erik Österlund]

Hi,

Mikael Gerdin noticed a compiler workaround could be done in a 
nicer-looking way.
So here goes a new webrev. Thanks, Mikael.

Incremental webrev: 
http://cr.openjdk.java.net/~eosterlund/8165860/webrev.00_01/
Full webrev: http://cr.openjdk.java.net/~eosterlund/8165860/webrev.01/

Tested with JPRT.

Thanks,
/Erik

On 2016-09-19 12:28, Erik Österlund wrote:
> Hi,
>
> This bug is a split out of the larger JDK-8033552 for adding volatile 
> qualifiers to lock-free code.
> The motivation is to make our implementation more robust since these 
> kind of issues have struck us a few times too many already.
>
> CR: https://bugs.openjdk.java.net/browse/JDK-8165860
> Webrev: http://cr.openjdk.java.net/~eosterlund/8165860/webrev.00/
>
> This specific CR handles the lack of volatile qualifiers in the 
> SubTasksDone and SequentialSubTasksDone classes in the workgroup.* files.
>
> SubTasksDone is missing volatile on the _tasks and _threads_completed 
> fields that are changed concurrently with atomics.
> SequentialSubTasksDone is missing volatile on the _n_claimed and 
> _n_completed fields that are changed concurrently with atomics.
>
> Testing: JPRT
>
> I will need a sponsor to push this.
>
> Thanks,
> /Erik