RFR: JDK-8077265 Modify assert to help debug JDK-8068448

[Stefan Karlsson]

On 2015-04-09 22:17, Eric Caspole wrote:
> Hi everybody,
> I updated this so the psOldGen part use a macro as Stefan suggested.
> The assert in psPromotionLAB.hpp is allocating out of an already 
> allocated PLAB, so I don't think that one will ever be hit but I want 
> it there just in case.
> And as Jesper suggested I made the message more helpful in the 
> original place.
>
>  http://cr.openjdk.java.net/~ecaspole/JDK-8077265/01/webrev/

I had hoped you would use the new define for all assert, but you've only 
used it for two out of four. If you're not going to use the same macro 
for all usages, it doesn't seem worth having.

http://cr.openjdk.java.net/~ecaspole/JDK-8077265/01/webrev/src/share/vm/gc_implementation/parallelScavenge/psOldGen.hpp.udiff.html

It seems to me that we could refactor allocate_noexpand and 
cas_allocate_noexpand to use a common function to do the assert and 
update the start array. That way you could get rid of the macro you added.

Thanks,
StefanK

>
> Passes JPRT.
> Thanks,
> Eric
>
> On 4/9/2015 10:01 AM, Stefan Karlsson wrote:
>> Hi Eric,
>>
>> On 2015-04-09 15:19, Eric Caspole wrote:
>>> HI everybody,
>>> Here is a webrev to add more asserts related to debugging 
>>> JDK-8068448. Beyond capturing more info in the original assert, 
>>> after looking at another core I added more asserts to make sure 
>>> there is no other place where old gen allocations would overrun the 
>>> start array.
>>
>> Why didn't these two new asserts get the same, more informative, 
>> error message as the first assert you changed? Maybe you could 
>> extract the check out to a helper macro that prints the relevant 
>> information?
>>
>> Another point that Bengt mentioned yesterday, is that we don't really 
>> need to print the old_gen part of the assert. It's already printed in 
>> the hs_err file.
>>
>> Thanks,
>> StefanK
>>
>>>
>>>  http://cr.openjdk.java.net/~ecaspole/JDK-8077265/00/webrev/
>>>
>>> Passes JPRT.
>>> Thanks,
>>> Eric
>>
>