JVM/TI code review request (XS and M) (7182152)

[Daniel D. Daugherty]

On 2/4/13 10:16 AM, Coleen Phillimore wrote:
> On 2/4/2013 11:50 AM, Daniel D. Daugherty wrote:
>> Thanks for the additional comment. Reply below.
>>
>>
>> On 2/4/13 8:34 AM, Coleen Phillimore wrote:
>>> On 2/4/2013 10:15 AM, Daniel D. Daugherty wrote:
>>>> Adding back the missing aliases and people...
>>>
>>> Sorry, I meant to send this re-all.
>>>
>>> I missed something major in my earlier review.
>>>
>>> The metadata->is_valid() flag should only be enabled in debug mode.  
>>> It adds a word to all metadata.
>>
>> Yes, I'm aware that it adds a word to all meta data. My change to
>> src/share/vm/oops/metadata.hpp was intentional. Personally, I would
>> prefer that is_valid() remain in the product bits for at least one
>> release cycle (JDK8). I'm a fan of sanity checks in product bits so
>> I actually wouldn't mind if it stay there permanently.
>>
>> However, if you insist, I'll backout the change to
>> src/share/vm/oops/metadata.hpp and redo the RedefineClasses()
>> sanity check code to be appropriately #ifdef'ed.
>
> Thanks, Dan.  I do.  People are actively trying to reduce metadata 
> right now, so having this additional word will cause a regression that 
> will be noticed for a special case.  is_valid() is a bit of a hack 
> too.  It relies on metadata being returned and given a non-zero bit 
> pattern which is only enabled in debug (iirc).

I enabled the setting of the non-zero bit pattern also (iirc).
However, I will back out those changes. I don't want to cause
grief for the metadata reduction effort.


> There's also a f1_as_method and f2_as_vfinal_method calls that return 
> Method* which might make the logic of your if statements simpler in 
> check_no_old_or_obsolete_entries().

Yes, Karen mentioned one of those in her review and asked for
that cleanup to be tracked in a followup bug. I noticed quite
a few "type cleanups" in that area in HSX-24 and I love them.
I'm presuming that you did that work, but I haven't chased the
history to ground.

Dan


>
> Thanks,
> Coleen
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/attachments/20130204/07b8ec6d/attachment-0001.html