RFR 8251118: BiasedLocking::preserve_marks should not have a HandleMark

[Daniel D. Daugherty]

On 8/11/20 4:27 PM, Patricio Chilano wrote:
> Hi Dan,
>
> Thanks for looking at this.
>
> On 8/11/20 4:53 PM, Daniel D. Daugherty wrote:
>> On 8/11/20 2:11 PM, Patricio Chilano wrote:
>>> Hi all,
>>>
>>> Please review the following small fix which involves removing the 
>>> added HandleMark in BiasedLocking::preserve_marks():
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8251118
>>> Webrev: http://cr.openjdk.java.net/~pchilanomate/8251118/v1/webrev/
>>
>> src/hotspot/share/runtime/biasedLocking.cpp
>>     No comments.
>>
>> As mentioned by Harold, adding a new test case to:
>>
>>     test/hotspot/jtreg/runtime/7158988/FieldMonitor.java
>>
>> that enables '-XX:+UseBiasedLocking' is a good idea.
> I suggested adding it to test TestFullGCALot.java instead because it 
> fails much more consistently.

I'm good with that also.


>
>> Also, Coleen added this note to your bug report:
>>
>>> Also in the patch for JDK-8249192 
>>> <https://bugs.openjdk.java.net/browse/JDK-8249192>, vframe.hpp 
>>> shouldn't include
>>> handles.inline.hpp (only cpp and inline.hpp files can include
>>> inline.hpp). It doesn't look like it needs handles.inline.hpp,
>>> only handles.hpp. 
>>
>> Were you planning on resolving that left over in this bug?
> Not really. I can change it here if you are okay though.

Your call on whether to fix it here or with a new bug. Seems
like fixing it here is less work... this bug is a follow-on to
the original and that comment is a follow-on to the original...

Dan


>
> Patricio
>> Dan
>>
>>
>>>
>>> I've inspected the callers of BiasedLocking::preserve_marks() and 
>>> they all have an assert that the current thread is the VMThread. 
>>> Since the VMThread creates a HandleMark object before executing a VM 
>>> operation the extra HandleMark added in 8249192 is not needed.
>>> I've run tiers1-3 in mach5 with -XX:+UseBiasedLocking and without 
>>> the patch I get several crashes in BiasedLocking::restore_marks(). 
>>> With the patch tests completed successfully.
>>>
>>> Thanks,
>>> Patricio
>>>
>>
>