Review request: 8025059: Metspace::should_expand mixes bytes and words in check against MaxMetaspaceSize

[Stefan Karlsson]

On 9/19/13 5:10 PM, Bengt Rutisson wrote:
>
> Hi Stefan,
>
> Given that we just want to get the byte/word conversion right I think 
> this change is fine. The bug JDK-8024547 contains a long list of 
> improvements so it is a bit difficult to tell, but the asymmetry with 
> using reserved memory for NonClassType and allocated memory for 
> ClassType will go away with some of the changes for JDK-8024547, right?
>
> 1345     size_t nonclass_allocated = 
> MetaspaceAux::reserved_bytes(Metaspace::NonClassType);
> 1346     size_t class_allocated    = 
> MetaspaceAux::allocated_capacity_bytes(Metaspace::ClassType);
> 1347     size_t real_allocated     = nonclass_allocated + real_allocated;

Yes. The current code we're working on calls 
MetaspaceAux::committed_bytes() directly.

StefanK
>
> Thanks,
> Bengt
>
>
> On 9/19/13 4:59 PM, Stefan Karlsson wrote:
>> http://cr.openjdk.java.net/~stefank/8025059/webrev.00/
>> https://bugs.openjdk.java.net/browse/JDK-8025059
>>
>> The following code in Metaspace::should_expand:
>>
>> if (!FLAG_IS_DEFAULT(MaxMetaspaceSize)) {
>>   size_t real_allocated = Metaspace::space_list()->reserved_words() +
>> MetaspaceAux::allocated_capacity_bytes(Metaspace::ClassType);
>>   if (real_allocated >= MaxMetaspaceSize) {
>>     return false;
>>   }
>>
>> doesn't convert Metaspace::space_list()->reserved_words() to bytes, 
>> as it should.
>>
>> Note that when JDK-8024547 gets fixed, this check will be rewritten 
>> to limit the amount of committed memory in both the Class and 
>> NonClass metaspaces. See:
>> https://bugs.openjdk.java.net/browse/JDK-8024547: MaxMetaspaceSize 
>> should limit the committed memory used by the metaspaces
>>
>> Testing: I've run our internal testing that sets the MaxMetaspaceSize.
>>
>> thanks,
>> StefanK
>