RFR (S) 8227766: CheckUnhandledOops is broken in MemAllocator

[Lois Foltan]

On 7/17/2019 12:22 PM, coleen.phillimore at oracle.com wrote:
>
> Due to some concerns about MemAllocator performance, and to only 
> create handles when needed, I have retested smaller change:
>
> open webrev at http://cr.openjdk.java.net/~coleenp/2019/8227766.02/webrev

Looks good.

gc/shared/memAllocator.cpp
- line #373-375: Since obj is already initialized to NULL to you need 
the else clause?

Thanks,
Lois

>
> Coleen
>
> On 7/17/19 10:49 AM, coleen.phillimore at oracle.com wrote:
>> Summary: Save oop created in handle more eagerly, so 
>> CheckUnhandledOops doesn't bash it.
>>
>> Also added a test for the case that was failing.  There were a couple 
>> of changes needed to compile CHECK_UNHANDLED_OOPS with slowdebug, but 
>> I reverted the makefile changes for doing that because I don't think 
>> we want it for slowdebug.
>> Lastly, made some changes to make CheckUnhandledOops easier to debug, 
>> and removed an unnecessary clearing, since it's also done in the 
>> transition.
>>
>> Tested with hs-tier1-3 with -XX:+CheckUnhandledOops and without.
>>
>> open webrev at 
>> http://cr.openjdk.java.net/~coleenp/2019/8227766.01/webrev
>> bug link https://bugs.openjdk.java.net/browse/JDK-8227766
>>
>> Thanks,
>> Coleen
>