RFR: JDK-8209389: SIGSEGV in WalkOopAndArchiveClosure::do_oop_work

[Jiangli Zhou]

Hi Ioi,

Thanks for the review and suggestions. I'll incorporate them.

Thanks,

Jiangli


On 8/14/18 6:05 PM, Ioi Lam wrote:
> Hi Jiangli,
>
> The changes look good. I think it's OK to exit the dumping VM because 
> normally we should not be archiving such large objects.
>
> For the various messages, I think we should include the object size 
> (in bytes).
>
> Also, for this message:
>
>  395       if (archived == NULL) {
>  396         ResourceMark rm;
>  397         tty->print("Failed to archive %s object " PTR_FORMAT " in 
> sub-graph",
>  398                    obj->klass()->external_name(), p2i(obj));
>  399         vm_exit(1);
>  400       }
>
> In addition to the size, I think we should also add obj->print_on(tty) 
> to help diagnosing the problems.
>
> Thanks
>
> - Ioi
>
> On 8/14/18 5:50 PM, Jiangli Zhou wrote:
>> Please review the following fix that addresses the issue for 
>> JDK-8209389. A Java object that's larger than one GC region cannot be 
>> archived as we currently don't support object spanning more than one 
>> archive heap region. The archiving code needs to check the 
>> MetaspaceShared::archive_heap_object return value and handle failure 
>> accordingly. Thanks Claes for finding the edge case and reporting the 
>> problem!
>>
>>   webrev: http://cr.openjdk.java.net/~jiangli/8209389/webrev.00
>>
>>   bug: https://bugs.openjdk.java.net/browse/JDK-8209389
>>
>> - java_lang_Class::archive_basic_type_mirrors
>>   Archived object returned by MetaspaceShared::archive_heap_object 
>> should not be NULL in these cases (basic type mirrors are not 
>> humongous). Added an assert.
>>
>> - HeapShared::archive_reachable_objects_from_static_field
>>   If the sub-graph entry object is too large, archiving is skipped 
>> for it’s referenced sub-graph and dumping process continues.
>>
>> - WalkOopAndArchiveClosure::do_oop_work
>>   Abort dumping when archiving failures due to extra-large object 
>> encountered during the sub-graph archiving.
>>
>> Tested with the new test case included in the webrev. Tier1 - tier4 
>> testing are in progress.
>>
>> Thanks,
>> Jiangli
>