RFR: 8255883: Avoid multiple GeneratedMethodAccessor for same NativeMethod… [v5]

[Hui Shi]

On Thu, 12 Nov 2020 12:23:36 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> @AlanBateman 
>> 
>>> What is the reason for using an int? I remember there was a suggestion for three states but two states seems okay so curious why it was changed from boolean to int.
>> 
>> shipilev suggested not to use sub-word CAS, so change compareAndSetBoolean to compareAndSetInt. Change field "generated" from boolean to int doesn't increase object size (no extra byte/boolean to fold into same word).
>> 
>>> The restoring to 0 in the event of failure should probably be a volatile-write. Might be clearer to declare it as a volatile.
>> 
>> "generated" field  is read once and CAS once in this method. It doesn't likely cached and no visibiliy order required.
>
> okay, although I think it would be clearer for maintainers to declare it as volatile because it is set with CAS.

@AlanBateman 

volatile attribute is added. As in common case, it only read and CAS at most once. And I see no regression on my testcase.

-------------

PR: https://git.openjdk.java.net/jdk/pull/1070