[9] RFR (XS): 8151623: Zap freed Metaspace chunks in non-product binaries

[Vladimir Ivanov]

Thanks, Dean.

Updated version:
   http://cr.openjdk.java.net/~vlivanov/8151623/webrev.01

On 3/10/16 10:43 PM, Dean Long wrote:
> This looks good.  I was experimenting with a similar change.  The
> comment nearby saying
> "Do not mangle freed Metachunks" made me wonder if it was safe. Could
> you update the
Good catch, fixed. Unless there's something useful stored after the 
header in a free chunk, it should be safe.

> comment if this is indeed safe?  Also, is there a Zap<something> flag we
> can use to turn
> this off and on?
Do you suggest a non-product or a diagnostic flag (to be able to turn it 
on in product binaries)?

Best regards,
Vladimir Ivanov

> On 3/10/2016 10:55 AM, Vladimir Ivanov wrote:
>> http://cr.openjdk.java.net/~vlivanov/8151623/webrev.00
>> https://bugs.openjdk.java.net/browse/JDK-8151623
>>
>> Zap freed Metaspace chunks in non-product binaries to catch stray
>> accesses to unloaded classes.
>>
>> Testing: JPRT, RBT (in progress): hotspot/test:hotspot_all,
>> jdk/test:tier1 & tier2, vm.parallel_class_loading.testlist,
>> vm.gc.testlist, BigApps w/ fastdebug binaries.
>>
>> Thanks!
>>
>> Best regards,
>> Vladimir Ivanov
>