RFR[XS]: 8238961 Assertion failure in new field layout code when ContendedPaddingWidth == 0.

[Frederic Parain]

Thank you Coleen.

Fred


> On Feb 13, 2020, at 10:39, coleen.phillimore at oracle.com wrote:
> 
> Looks good!
> Coleen
> 
> On 2/13/20 9:54 AM, Frederic Parain wrote:
>> Please review this very small fix in field layout code.
>> 
>> The issue is that option ContendedPaddingWidth can be set to zero,
>> causing an assertion failure when trying to create a padding block
>> of size zero. One site inserting padding blocks was protected against
>> zero padding width, but another site was not. This fix makes the
>> second site robust against this case.
>> 
>> CR: https://bugs.openjdk.java.net/browse/JDK-8238961
>> Webrev: http://cr.openjdk.java.net/~fparain/8238961/webrev.00/index.html
>> 
>> Testing:
>>   - tests test/hotspot/jtreg/runtime/contended manually run with ContendedPaddingWidth
>>     forced to zero (tests fails because they are not designed to support the case
>>     where the padding width is zero, but the VM doesn’t crash anymore because of the
>>     assert)
>>   - tier 1-3
>> 
>> Thank you,
>> 
>> Fred
>> 
>